National Academies Press: OpenBook
« Previous: 2 Transportation Package Safety
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

3
Transportation Risk

The original statement of task for this study (Sidebar 1.1) directs the committee to examine the “principal risks” for transporting spent fuel and high-level waste; determine how well these risks are understood; and compare them to other risks that confront members of society. Those tasks are addressed in this chapter.

As noted in Chapter 1, risk is a multidimensional concept: It includes health and safety risks that arise from exposures of workers and members of the public to radiation from shipments of spent fuel and high-level waste. It also includes social risks that arise from social processes1 and people’s perceptions,2 even in the absence of radiation exposures. The health and safety risks and social risks are collectively referred to as societal risks in the statement of task given in Sidebar 1.1.

A great deal of work has been carried out over the past four decades to understand the risks (Sidebar 3.1) arising from the transport of spent fuel, both in the United States and abroad. Although the principal focus of this

1  

Social process is defined as “a characteristic mode of social interaction” (Webster’s Third New International Dictionary). Social interactions shape the communities in which people live by, for example, influencing choices about where to purchase or rent a home, where to work, and where to send children to school.

2  

Perception is defined as the “integration of sensory impressions of events in the external world … as a function of nonconscious expectations derived from past experience” (Webster’s Third New International Dictionary). Perceptions can have a strong influence on peoples’ behavior, whether or not such perceptions are an accurate picture of reality.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

SIDEBAR 3.1
Background on Risk

Risks for spent fuel and high-level waste transportation arise from conventional vehicular accidents and exposures to ionizing radiation under both normal and accident conditions. Radiation risks are primarily a concern for people who live near, or travel on, spent fuel shipment routes.

Risk considers both the likelihood of occurrence of a specific hazard and its consequences. Frequently, one considers several scenarios that involve different kinds of hazards, each with a different likelihood of occurrence and consequence. One way in which risk can be expressed is in terms of a triplet (Kaplan and Garrick, 1981):

Where, for spent fuel shipments,

  • Scenarios represents transport conditions that can lead to an exposure to ionizing radiation from either routine operations or severe accidents,

  • Probability expresses quantitatively the likelihood that a scenario will actually occur during one shipment; it is expressed as a dimensionless quantity that ranges in value from 0 (impossible) to 1 (certain)—for example, a probability of 0.5 indicates that a particular scenario has a 50 percent chance of occurring, and

  • Consequences describe the undesirable results if the scenario does occur: for example, undesirable health effects.

The risks from spent nuclear fuel transport can be characterized by several measures. For example, risk can be expressed in terms of the expected number of deaths per quantity of spent fuel transported, per number of packages shipped, or per number of package shipments. It also could be expressed in terms of the number of deaths expected for a specific subpopulation exposed to ionizing radiation, for example, the subpopulation of transportation workers. Although they are difficult to quantify, consequences may also include socioeconomic outcomes.

The choice of scenarios and consequences selected for a risk calculation can make a difference in how that risk is understood by potentially affected populations. A risk may be understood as low by one measure in comparison to another, even though the same risk is being considered (NRC, 1996). This has implications for informing decision makers, for communicating about risks with non-experts, and for the legitimacy of risk comparisons in the eyes of interested and affected people (NRC, 1989, 1996). Comparing risks arising from fundamentally different activities also requires care in the selection of appropriate scenarios and consequences. This point is discussed in more detail elsewhere in this chapter.

report is on transportation in the United States, much can be learned from international experiences. Spent fuel and high-level waste are being transported in many other countries, in some cases in much greater quantities than in the United States. The committee has drawn upon the experiences

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

of foreign transportation programs to inform its judgments. This information has been acquired through the review of published documents and from first-hand experience.3

Transportation risks can arise both during normal transport operations and from accidents involving loaded spent fuel or high-level waste shipping packages.4Table 3.1 describes the transportation impacts for these two operational scenarios. These risks can also arise from incidents (e.g., terrorist attacks) involving packages containing spent fuel or high-level waste; such incidents are not addressed in this report (see Section 1.2).

The health and safety risks to be discussed in this chapter arise from exposures of people who travel, work, or live near transportation routes, and transportation workers themselves, to radiation (Sidebar 3.2) from loaded spent fuel and high-level waste transportation packages. During normal operations, such exposures can occur as the result of radiation shine5 from transportation packages loaded with spent fuel or high-level waste. Although the radiation doses to individuals near transport routes are likely to be very low, large numbers of individuals may receive exposures, producing a “collective dose” that can be used to estimate health impacts (see Sidebar 3.3). Degradation and/or loss of package containment in a severe accident has the potential to increase such radiation exposures and possibly result in the release of radioactive material from the package to the environment, although the committee notes in Chapter 2 that the robust design of transportation packages makes such releases unlikely.

Health and safety risks are frequently characterized in terms of human health effects: for example, injuries and loss of human life. Modern society generally considers such consequences to be the most severe harms that can

3  

Committee member Clive Young has extensive experience with the transport of spent fuel in the United Kingdom. In addition, a group of committee members visited Germany and the United Kingdom in September 2004 (see Appendix B) to obtain first-hand information about European transportation programs.

4  

International Atomic Energy Agency regulations for the safe transport of radioactive materials define three levels of severity for transportation conditions: routine conditions of transport, normal conditions of transport, and accident conditions of transport. Routine conditions are free of any transport mishaps; normal conditions can involve minor mishaps due to rough handling or exposure to weather. Accidents subject packages to severe conditions that well exceed normal conditions of transport.

5  

Transportation packages contain heavy shielding to protect workers and the public from the radiation emitted by the spent fuel or high-level waste contained within them. The packages are effective in shielding well over 99 percent of this emitted radiation, but a small amount (below regulatory limits) of radiation, primarily gamma rays, can escape from the interior of the packages and provide external doses to workers and the public. This report uses the term radiation shine to refer to this external radiation.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.1 Transportation Risks Examined in this Report

Transportation Conditions

Transportation Impacts

Health and Safety Risks

Social Risks

Normal

Health impacts arising from the emission of radiation (i.e., radiation shine) from transportation packages

Direct socioeconomic impacts: loss of economic or social well-being as a direct result of transportation program operations

 

 

Perception-based impacts: anxiety and associated illness; loss of property values; and reduced economic activity

Accidents

Health and environmental impacts arising from elevated radiation and/or the physical release of radioactive material as a result of the degradation or loss of package containment

Direct socioeconomic impacts: Temporary loss of transportation route use and associated business disruptions such as a loss of tourism

 

 

Perception-based impacts: social amplification of the normal impacts as a result of accidents; these can result in secondary or tertiary impacts, including stigmatization of people and places; loss of trust in transportation program management; moratorium on transportation program operations; and/or increased program costs

result from any hazard, especially anthropogenic hazards that can be controlled through regulation. Society places a high value on human life and routinely demands that governments strictly regulate life-threatening hazards. Reductions in severe injuries and loss of human life are generally considered to be primary measures of regulatory effectiveness. Because of this emphasis on protecting human life, risk assessment experts have developed methodologies to quantitatively estimate risks to human life. Sidebar 3.1 provides a description of one way in which such risks are estimated.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

Social risks can have both direct socioeconomic and perception-based impacts such as those shown in Table 3.1. These risks may reduce the desirability of living and working in communities associated with spent fuel and high-level waste transportation operations. The social risks of interest in this chapter are harder to measure than the corresponding health and safety risks, and even identifying cause-and-effect relationships can be difficult. The impacts of social risk occur within a much larger sphere of social and economic activities that can mask important effects. The measurement of perception-based impacts can be especially difficult, because it frequently requires the use of surveys to measure people’s anticipated, rather than actual, behaviors.

The health and safety risks and the social risks associated with spent fuel and high-level waste transportation can have significant interactions. Increases in radiation exposures or in the incidence of health effects from transportation operations (e.g., because of well-publicized mishaps, accidents, or fatalities) may, over time, increase the perception-based impacts. On the other hand, transportation operations that are carried out without demonstrable health impacts may, over time, reduce the perception-based impacts. A shipping incident or accident that leads to a moratorium on transportation operations might well change the entire profile of social risks associated with a transportation program.

There is another class of nonradiological impacts that are not considered in detail in this chapter: conventional vehicular impacts associated with the transportation of spent fuel and high-level waste. These include the health impacts of exhaust emissions from transport conveyances and vehicular accidents that result in fatalities, injuries, and property damage. While these impacts are real and predictable, they generally do not garner the same level of awareness or concern among members of the public as the radiation-based impacts described previously. Moreover, it could be argued that given the higher standards for driver training and equipment maintenance, and the conduct of vehicle and package inspections and operations for spent fuel and high-level waste transportation, conventional vehicular impacts associated with accidents would actually be lower than for other types of hazardous materials or heavy-freight transport. In any case, spent fuel and high-level waste transportation programs are a very small component of the overall transport system for hazardous materials, as measured both by load mass and by volume of traffic.

The committee provides an examination of health and safety risks of spent fuel and high-level waste transportation in Section 3.1. The social risks are examined in Section 3.2, and the risk comparisons called for by the study charge (see Sidebar 1.1) are described in Section 3.3. The committee’s findings and recommendations on transportation risks are provided in Section 3.4.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

SIDEBAR 3.2
Radiation Dose

Materials that are radioactive are unstable (i.e., the nuclei in the atoms of the material possess too much energy) and transform spontaneously (decay) through the emission of radiation. This radiation may be in the form of energetic particles, such as alpha particles, beta particles, or neutrons, or energy may be emitted in the form of electromagnetic radiation (e.g., gamma rays). Collectively these emissions are known as ionizing radiation because they are sufficiently energetic to directly or indirectly ionize the matter (i.e., remove electrons from the atoms) they travel through.

Absorption of radiation energy by a cell of a living organism can alter its chemical and physical state. The absorption of large amounts of radiation can produce short-term or “acute” effects in the cell. The most severe effect would be cell death. Small amounts of radiation (not sufficient to cause cell death) potentially can damage the cell’s genetic material (i.e., DNA contained in the chromosomes). If the cell’s natural repair mechanisms cannot repair this damage correctly, it may lead to the induction of cancer at some future time. Because of the long time periods involved in their development, such cancers are referred to as “latent.”

The following quantities are commonly used to characterize radiation exposures in living organisms:

  • Absorbed dose. The quantity of ionizing radiation deposited into an organ or tissue, expressed in terms of the energy absorbed per unit mass of tissue. The basic unit of absorbed dose is the rad or its SI (international system of units, also known as the metric system) alternative the gray (Gy; 1 Gy = 100 rad).

  • Equivalent dose. The absorbed dose averaged over the organ or tissue of interest multiplied by a weighting factor that accounts for the differences in biological effects (per unit of absorbed dose) for different types of radiation. The weighting factor ranges from 1 for X-rays and gamma rays to 20 for alpha particles and some neutrons. The equivalent dose is expressed in units of rem or its SI alternative the sievert (Sv; 1 Sv = 100 rem).

  • Effective dose. A measure of dose that accounts for the differences in biological effects of different types of radiation and for the varying sensitivity of different organs to the biological effects of radiation. Effective doses are also expressed in rem or sieverts.

Radiation and radioactivity can be found in nature in a number of different forms. The natural radiation environment consists of cosmic and solar radiation, external radiation from radioactive materials present in rocks and soil, and inhaled

3.1 HEALTH AND SAFETY RISKS

Two approaches are used in this section to estimate the health and safety risks of spent fuel and high-level waste transportation: (1) an examination of the worldwide record of spent fuel transport (Section 3.1.1); and

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

and ingested radioactive materials from air, food, and water. These sources have been present since the creation of Earth and provide an effective dose to all living organisms. The table below shows that, worldwide, the average annual effective dose to individuals is about 2.4 millisieverts (mSv; 240 millirem). This annual exposure is a good starting point to use in judging the magnitude of equivalent doses received from man-made sources. The National Council on Radiation Protection and Measurements (NCRP, 1987) estimates that man-made sources of radiation and radioactivity contribute an additional effective dose of 0.6 mSv (60 millirem) annually to an average person living in the United States. Most of this dose is due to medical procedures such as diagnostic X-rays and nuclear medicine procedures. Since the NCRP report was published, new diagnostic medical procedures that utilize ionizing radiation (especially computed tomography scanning) have come into wide use in the United States. Consequently, the average annual doses from medical procedures are probably increasing.

It is important to keep in mind that the effective dose statistics presented in this sidebar are averages. Individuals can receive much more or much less than the average depending on where they live (i.e., location as well as height above sea level), the type of house in which they reside, their occupation, the medical procedures they undergo, and many other factors determined by the individual life-style (e.g., air travel, watching television, diet).

TABLE Worldwide Exposure to Natural Sources of Radiation and Radioactive Material

Source of Exposure

Average Annual Effective Dose, mSv (millirem)

Typical Range of Effective Doses, mSv (millirem)

Cosmic radiation

0.39 (39)

0.3–1.0 (30–100)

External terrestrial radiation

0.48 (48)

0.3–0.6 (30–60)

Inhalation (U, Th, 222Rn, 220Rn)

1.26 (126)

0.2–10.0 (20–1,000)

Ingestion (40K)

0.29 (29)

0.2–0.8 (20–80)

Total

2.42 (242)

1.0–10.0 (100–1,000)

 

SOURCE: Adapted from UNSCEAR (2000, Annex B, Table 31).

(2) an examination of the principal quantitative risk analyses that have been carried out for spent fuel and high-level waste transport, including the analysis for transporting spent fuel and high level-waste to a federal repository at Yucca Mountain, Nevada (Section 3.1.2).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

SIDEBAR 3.3
Collective Dose and Latent Cancer Fatalities

Collective dose is defined as the sum of all radiation doses received by all members of a population at risk (NCRP, 1995). The units of collective dose are usually given as person-sieverts or person-rem. This concept is frequently used in radiation protection applications, both for controlling actual exposures and for estimating potential exposure risks. The use of the collective dose for radiation protection purposes assumes the following (NCRP, 1995):

  1. There is a direct proportionality between radiation dose and risk over their respective ranges of concern.

  2. Risk is independent of dose rate.

  3. A radiation dose leads to an identical risk whether it is administered to a single individual or to a population.

NCRP (1995, p. 1) notes that “[w]hile these assumptions may or may not be valid, they are considered to be conservative and have been generally accepted by the scientific community concerned with radiation protection.”

The Department of Energy (DOE) used the collective dose concept to estimate latent cancer fatalities (LCFs) in the final Yucca Mountain Environmental Impact Statement (EIS). These cancers are expected to be produced many years after a radiation dose is received (i.e., after a latency period) and are never traceable directly to the received dose. DOE calculated collective doses for populations of workers and the public from prospective exposures to radiation from its transportation program. These doses were calculated using computer programs such as RADTRAN (see Sidebar 3.4). DOE then estimated the number of latent cancer fatalities using the International Commission on Radiological Protection (ICRP, 1991) recommended conversion factors: 5 × 10−4 latent cancer fatality per person-rem (5 × 10−2 per person-sievert) of collective dose for the general public and 4 × 10−4 latent cancer fatality per person-rem (4 × 10−2 per person-sievert) of collective dose for workers; these factors were doubled when doses greater than 20 rem are received over short time periods. The conversion factor for the public is higher because it applies over an entire lifetime, whereas the factor for workers applies only for working ages.

Radiation is a weak carcinogen at the low doses involved in the routine transport of spent fuel and high-level waste. Consequently, the incremental increase in latent cancers from low doses of radiation is very small relative to the natural occurrence of this disease in human populations. Moreover, radiation-induced cancers do not have any special characteristics that allow them to be differentiated from cancers developed from other causes.

3.1.1 Historical Record of Spent Fuel Transport

Spent fuel has been transported routinely in more than a dozen countries, including the United States, for many decades. The quality of record keeping on these shipments varies significantly, especially between the mid-

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

1940s and 1970s. The committee first provides a brief review of the transportation experience in the United States and then examines experiences in some other countries.

U.S. Transportation Experience

The United States has been transporting irradiated nuclear fuel since World War II. The first irradiated fuel shipments were made by the Manhattan Project as part of the national effort to develop atomic weapons. More than 170,000 MTHM6 of irradiated fuel were transported within the Hanford (Washington) and Savannah River (South Carolina) sites as part of the nuclear weapons production effort between 1944 and the end of the Cold War in the late 1980s. Most of this transport occurred over very short distances (a few kilometers [miles]) on publicly restricted lands, mostly by rail.

By the early 1960s, civilian spent fuel was being transported routinely on the nation’s road and rail systems by the Atomic Energy Commission (AEC).7 In 1974, the AEC was reorganized,8 and authority for regulating the commercial transport of radioactive materials transportation was given to the newly established U.S. Nuclear Regulatory Commission (USNRC). The most complete records of spent fuel transportation date from the creation of this agency.

Most spent fuel transport across the nation’s public highways and private railroads has involved small-quantity shipments of commercial spent fuel. Estimates of quantities of commercial spent fuel shipments are available from several sources. Pope et al. (1991, 2001) provide commercial spent fuel shipping estimates since 1964. These estimates were developed from Department of Energy (DOE) and Department of Transportation (DOT) databases supplemented with data from the USNRC and private sources. Pope et al. (1991) note that their estimates do not include shipments from six commercial reactors because of the difficulty in obtaining data.

6  

Metric tons of heavy metal, where the heavy metal is uranium. This is a commonly used measure of fuel quantity. For comparison purposes, a typical reactor core contains about 100 MTHM (110 short tons) of nuclear fuel. A typical truck transport package typically holds between 0.5 and 2 MTHM (0.55 and 2.2 short tons) of spent fuel; a typical rail package holds between 10 and 18 MTHM (11 and 20 short tons).

7  

The AEC was created by the Atomic Energy Act (also known as the McMahon Act) in 1946 to control and promote the use of nuclear power.

8  

The Energy Reorganization Act of 1974 abolished the AEC and created two federal agencies in its place: the Nuclear Regulatory Commission and the Energy Research and Development Administration. The Energy Research and Development Administration became the Department of Energy after the Energy Reorganization Act of 1977.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.2 Commercial Spent Nuclear Fuel Shipments in the United States, 1964–2004

Time Period

Mass of Spent Fuel Shipped (MTHM)

Number of Shipments

Highway

Rail

Highway

Rail

1964–1978

473

348

1565

126

1979–1997

356

1097

1181

153

1998–2004

16

766

102

261

Totals

845

2211

2848

540

NOTE: MTHM = metric tons of heavy metal.

SOURCES: Pope et al. (1991, 2001); USNRC, written communication, 2005.

Additional unpublished information was made available to the committee from Energy Resources International (Supko, 2000; Supko, 2005, written communication) and the USNRC (USNRC, 2005, written communication). The latter communication provided shipping data for 1998–2004 based on shipper notifications required under regulation 10 CFR Part 73.9 This communication is an update of USNRC’s public circular on spent fuel shipments (USNRC, 1998). Updated information has not been released since the September 2001 terrorist attacks. The agency was preparing an updated version for public release when the present report was being finalized in December 2005.

Table 3.2 provides an estimate of commercial spent fuel shipments in the United States since 1964. The committee was not able to assess the completeness or accuracy of these data, except to note that the pre-1979 data are likely incomplete. Information on spent fuel shipments prior to 1964 is not available, although accident and incident reports dating back to the mid-1950s are available, as discussed elsewhere in this chapter.

One conclusion that can be drawn from these data is that the previous U.S. spent fuel shipping experience as measured by the total number of shipments or mass of spent fuel shipped is small compared with anticipated future transportation campaigns. The federal repository and Private Fuel Storage, LLC, programs, for example, plan to ship about 20 and 13 times, respectively, the amount of commercial spent fuel that has been shipped in the United States since 1964. Moreover, both programs plan to ship spent fuel primarily by rail. The planned number of rail shipments to a federal

9  

Code of Federal Regulations, Title 10, Part 73: Physical Protection of Plants and Materials.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

repository at Yucca Mountain under the mostly rail scenario (9600 shipments; see Table 3.8) is approximately 18 times the number of rail shipments that have occurred in the United States since 1964.

Spent nuclear fuel shipments in the United States are usually made under the USNRC’s or DOT’s exclusive use regulations (10 CFR 71.47(b)).10 Such shipments can be transported using public road and rail systems in the United States only if they do not exceed the following dose limits:

  • 2 millisieverts (mSv) per hour (200 millirem [mrem] per hour) (see Sidebar 3.2) on the external surface of the transport package11 and at any point on the outer surface of the vehicle.

  • 0.1 mSv per hour (10 mrem per hour) at any point 2 meters (6.5 feet) from the outer lateral surfaces (but not the top or bottom) of the vehicle.

  • 0.02 mSv per hour (2 mrem per hour) in any normally occupied space. This provision does not apply to private carriers if exposed personnel under their control wear approved radiation dosimetry devices.12

U.S. agencies do not collect records of radiation exposures resulting from the transportation of irradiated nuclear fuel as is done for personnel exposures in nuclear power plants. Private carriers will keep records for those workers who use radiation monitoring devices in accordance with regulations, but these records are not published. Consequently, the doses received by workers and the public associated with spent nuclear fuel shipments in the United States are not precisely known, although the committee judges that they are likely to be relatively small given the external dose limits allowed by regulations combined with the small numbers of shipments that have been made to date. Estimates of doses to populations and to hypothesized maximally exposed individuals in future shipments have been made by the USNRC, DOE, and DOT based on the projected number and characteristics of shipments and the populations that live in the proximity of planned transportation routes. These estimates have generally assumed that the dose rates from the packages are the maximum allowed

10  

Exclusive use is defined in 10 CFR 71.4 as “sole use by a single consignor of a conveyance for which all initial, intermediate, and final loading and unloading are carried out in accordance with the direction of the consignor or consignee. The loading and unloading must be carried out by personnel having radiological training and resources appropriate for the safe handling of the consignment.”

11  

A limit of 10 mSv per hour (1000 mrem per hour) applies when the shipment is made in a closed transport vehicle in which the package is secured so that its position remains fixed and there are no loading or unloading operations between the beginning and end of transportation.

12  

In this case, the normal occupational dose limits apply (see Table 3.10).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

under USNRC or DOT regulations. This is illustrated elsewhere in this chapter for the planned transportation program to a federal repository at Yucca Mountain.

Information on accidents and incidents involving spent fuel shipments in the United States has been reported since the late 1940s. Data for 1949–1971 are provided in AEC reports. In 1971, DOT established the Hazardous Materials Incident Reporting System (HMIS).13 This computerized database contains information on incidents involving the interstate transportation of hazardous (including radioactive) materials by air, highway, rail, and water. DOT regulations (49 CFR 171.15) require that all accidents and incidents involving radioactive materials transport that meet one or more of the following criteria be reported to it for inclusion in this database:

  • Deaths or injuries requiring hospitalization

  • Property damage in excess of $50,000

  • Evacuations of the public that last for one or more hours

  • Closure of major transportation arteries or facilities

  • Changes to flight patterns or routing of aircraft

  • Fire, breakage, spillage, or suspected contamination involving radioactive materials

  • Unintentional release from a package or any discharge during transportation

USNRC regulations (10 CFR 20.2201-2206; 10 CFR 73.71) also require that thefts, exposures, and releases of radioactive materials be reported.

In 1981, the Transportation Technology Center at Sandia National Laboratories established the Radioactive Material Incident Report (RMIR) database (Weiner and Tenn, 1999). This database contains information about radioactive materials transportation incidents that have occurred in the United States since 1971. It incorporates information from the HMIS in addition to information from the USNRC and other organizations such as state radiological authorities and the media.

The RMIR records accidents involving vehicles carrying radioactive materials that involve fatalities or injuries or that involve sufficient damage that the vehicle cannot move under its own power. It also records incidents that involve actual or suspected releases or surface contamination that exceeds regulatory limits. This database was discontinued in 1998 due to funding cutbacks. DOT’s HMIS is now the primary source of data on hazardous material transportation incidents in the United States.

13  

Information about this database can be found on the DOT Web site at http://hazmat.dot.gov/abhmis.htm.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.3 Summary of Spent Fuel Shipping Accidents and Incidents, 1949–1996

Time Period

Accidents or Incidents Reported

Radioactive Material Contaminationa

Surface Contaminationb

No Description

Vehicular Deathsc

1949–1970

14

6

None reportedd

2

1

1971–1996

58

2e

49

0

1

aAny detectable loss, dispersal, or escape of radioactive material from the package’s containment system.

bDetectable non-fixed contamination on external surfaces.

cDeaths caused by vehicular accidents, not the release of radiation.

dIt is unclear whether surface contamination was routinely tested for or reported during this period.

eOne incident (in 1984) involved an empty package; the other (in 1976) involved a pinhole leak of coolant or moderator on the outside jacket of the package, not the release of spent fuel.

SOURCE: Data compiled by DOE Office of Civilian Radioactive Waste Management.

A summary of available data on transportation accidents and incidents is provided in Table 3.3. These data were compiled by DOE’s Office of Civilian Radioactive Waste Management. According to DOE, the AEC reported radioactive material contamination incidents between 1949 and 1970. This contamination involved the package and/or the conveyance and in some cases the surrounding environment. Two additional radioactive material contamination incidents were reported between 1971 and 1996. One involved an empty package, and the other involved a pinhole leak of coolant or moderator. These older incidents apparently involved packages that were designed to transport spent fuel in water for cooling and shielding, and the leaks presumably involved the release of small amounts of this water through holes in pipes, valves, and seals. At present, only spent fuel cooled for more than five years is transported in the United States, and all spent fuel is transported in a dry state. However, some package designs still utilize water jackets for shielding neutrons, but these are physically separated from and are not in contact with the interior of the package.

Most of the reported incidents did not involve package leaks, but rather the detection of non-fixed surface contamination14 on the transport pack-

14  

Non-fixed contamination adheres to the outer surfaces of the package and can be detected by wiping. The limits for such contamination, which are established by international standards and U.S. regulations (49 CFR 173.443 and 10 CFR 71.87 (i) by reference to 49 CFR 173.443), are as low as reasonably achievable and not to exceed 4 becquerels per square

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

ages, and these incidents were described as minor. Such surface contamination typically results from inadequate decontamination of packages following the loading of spent fuel.15 However, there is no confirmation of cause of contamination in the database.

Table 3.4 provides a list of transportation accidents involving spent fuel transport packages between 1971 and 2005 in the United States. There were four accidents involving trucks and five accidents involving trains during this time.16 None of these accidents resulted in the release of radioactivity. It is important to recognize that all but the December 1971 accident were minor in that they did not result in severe impacts or fires that would test the integrity of transport package containment. However, claims about this safety record in the United States have to be interpreted carefully given that spent fuel transport quantities are quite limited, especially for rail transport.

The U.S. government opened a repository for the disposal of defense transuranic waste in New Mexico in 1999. This repository, the Waste Isolation Pilot Plant (WIPP), had, as of April 2005, received shipments of waste from eight DOE sites across the continental United States. About 3500 truck shipments traveling about 3.5 million truck-miles had been made to the repository as of April 200517 using Type B packages of a special design mounted on legal-weight trucks. To date, there have been three highway accidents involving WIPP shipments. None resulted in the release of radioactivity from the transportation package to the environment.

Worldwide Transportation Experience

There is no centralized database for the worldwide shipment of radioactive materials, nor is there an international mandate to collect such infor-

   

centimeter averaged over a 300 square centimeter sampling area for beta, gamma, and low-toxicity alpha emitters, and one-tenth that limit for other alpha emitters. The International Atomic Energy Agency (IAEA) recently issued a technical document resulting from a coordinated research project aimed at evaluating the adequacy of these limits under current radiological protection and transportation practices. The document notes (IAEA, 2005b, p. 84) that “the studies carried out under [the research project] indicate that the present limits on non-fixed contamination on the surfaces of packages and conveyances are conservative.”

15  

Contamination occurs when the package is placed into the spent fuel pool for loading and is contaminated with small amounts of radioactive material present in the pool water. The external surfaces of these packages are decontaminated to remove non-fixed contamination before shipment.

16  

It is interesting to note that while the number of rail accidents exceeded the number of truck accidents during this period, the number of truck shipments was much higher (Table 3.2). Between 1979 and 2004, for example, there were roughly three times more truck shipments than rail shipments.

17  

http://www.wipp.ws/shipments.htm. Accessed on April 18, 2005.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.4 Summary of Transportation Accidents Involving Commercial Spent Fuel Packages, 1971–2005a

Mode

Date

Location

Description

Truck

December 8, 1971

Tennessee

Package thrown free of trailer and landed in ditch following head-on collision with car. No package damage or release. Driver killed

Truck

February 2, 1978

Illinois

Trailer collapse while crossing railroad tracks. No package damage or release

Truck

August 13, 1978

New Jersey

Trailer collapse while empty package was being loaded. Package not damaged

Truck

December 9, 1983

Indiana-Illinois border

Trailer’s fifth wheel failed. No package damage or release

Train

March 29, 1974

North Carolina

Empty package struck by a derailed tank car on adjacent track. Superficial package damage. No release

Train

March 24, 1987

Missouri

Train-auto collision at grade crossing. No package damage or release

Train

January 9, 1988

Illinois

Train carrying empty packages derailed. No damage to packages

Train

December 14, 1995

North Carolina

Railway car carrying empty packages derailed. No damage to packages

Train

September 22, 2005

New York

Railcar carrying an empty spent fuel package derailed in a rail yard. Railcar tipped over. No release

aThis table lists only accidents involving loaded and empty spent fuel packages; it does not include all of the incidents listed in Table 3.3.

SOURCES: Weiner and Tenn (1999); data from the RMIR compiled by Energy Resources International (December 11, 1997) and DOE correspondence; media reports (for the 2005 accident).

mation. However, since 1980, the International Atomic Energy Agency (IAEA)18 has been collecting such data at the recommendation of its transportation advisory committee.19 The agency is developing databases on

18  

The IAEA was established under the United Nations in 1957 as part of the “Atoms for Peace” program to promote the safe, secure, and peaceful uses of nuclear technologies.

19  

The Standing Advisory Group on the Safe Transport of Radioactive Material was the predecessor body to the Transport Safety Standards Committee (TRANSSC). Committee member Clive Young is a past chairman of TRANSSC.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

radioactive materials shipments, accidents, and radiation exposure. Member states provide information to these databases on a voluntary basis. The response of member states to requests for information to populate these databases has been mixed. Consequently, the databases are incomplete and contain only a limited representation of available data.

As part of this database development effort, the IAEA launched a literature search and a series of informal contacts with 25 member countries in 2000 to obtain information on worldwide shipments of spent fuel20 and high-level radioactive waste. A summary of this information was provided in a paper published by IAEA staff (Pope et al., 2001; see Table 3.5). This information is characterized by Pope et al. (2001) as “informal and incomplete” because not all countries responded, and some respondents provided incomplete data or data that were inconsistent with other published sources.

Although the data are incomplete, they nevertheless allow several useful observations to be made about the worldwide spent fuel transportation experience. Spent fuel is being transported within and across the borders of many countries. Worldwide, a major purpose for shipping spent fuel is to reprocess it. Reprocessing facilities have been constructed in France (La Hague) and the United Kingdom (Sellafield) for reprocessing domestic and foreign spent fuel. Belgium, Germany, Italy, Japan, and Spain have shipped spent fuel to these facilities for reprocessing, and some return shipments of high-level waste have been made to some of these countries. Spent fuel from Finland also has been shipped to the USSR or Russia for reprocessing. Most of the other spent fuel shipments being made within or between countries are for the purpose of interim storage.

The total quantity of spent fuel shipped worldwide was estimated in the 2001 IAEA study (see Table 3.5) to be between about 73,000 and 98,000 MTHM. The amount of spent fuel shipped in the United States is small in comparison. The total quantity of spent fuel transported worldwide also exceeds the legislated capacity of Yucca Mountain (70,000 MTHM) and is about twice the planned capacity of Private Fuel Storage (40,000 MTHM). Moreover, a majority of the worldwide spent fuel shipments have been by rail, the preferred mode for shipping to Yucca Mountain and Private Fuel Storage. Shipments to reprocessing plants in France and the United Kingdom have been made for more than 35 years. In contrast, the shipment of the first 70,000 MTHM of spent fuel and high-level waste to a federal repository or interim storage facility would likely take place over periods of a little more than two decades.

Spent fuel rail shipments to France are made using general and dedicated trains, whereas shipments within the United Kingdom are made using

20  

The IAEA refers to this fuel as “irradiated nuclear fuel.”

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.5 Worldwide Spent Fuel Transportation Estimates

Country of Origin

Mass of Spent Fuel Shipped (MTHM)a

Number of Packages Shipped

Shipping Modes

Destination

Canada

100

187

 

Czech Republic

242

65

Rail

To and from Slovakia

Finland

233

65

Highway and rail

USSR or the Russian Federation

France

 

Domestic

11,700

2,600

Mostly rail

La Hague

Other Europe

10,000

2,500

Mostly rail

La Hague

Japan

2,940

660

Sea and highway

La Hague

Germany

>25

66

Highway and rail

Domestic

Hungary

258

72

 

Italy

81

52

Highway

Domestic

Japan

 

1995–1999

161

50

Sea and land

Domestic

2000–2004 (proj.)

1,700

 

Sea and land

 

Russian Federation

3,500

500

 

Domestic

Slovakia

239–380

635–700

 

Sweden

3,300

1,100

Sea

Domestic

Ukraine

1,300

300

 

United Kingdom

 

Domestic

20,900–43,200

11,300–28,900

Mostly rail

Sellafield

Other Europe

2,860

1,100

Rail

Sellafield

Japan

4,720

1,420

Sea and rail

Sellafield

United States

2,270

3,020

Highway and rail

Domestic

Approximate Totals

73,000–98,000

24,000–43,000

 

aNumbers are rounded to three significant figures.

SOURCE: Modified from Pope et al. (2001).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

dedicated trains.21 DOE recently announced that it planned to use dedicated trains when possible for shipments to a U.S. federal repository (see Chapter 5). The shipments in Europe share the rails with other freight and passenger trains. This is similar to current plans for spent fuel shipments in the United States. Moreover, trains carrying spent fuel in France and the United Kingdom are on routes that pass through large cities. This too is likely to be the case for spent fuel and high-level waste transport in the United States because many mainline rail routes pass through large cities. Some of the spent fuel being transported to La Hague and Sellafield is cooled for less than a year before being shipped.22 In contrast, current practice in the United States is to cool commercial spent fuel for at least five years before shipping it, and some of the spent fuel to be shipped to Yucca Mountain will have been cooled much longer than five years.23 Road and rail shipping distances to La Hague and Sellafield are generally 1000 kilometers (about 600 miles) or less, compared with the several thousand kilometers for shipping spent fuel from the eastern United States to interim storage or a federal repository in the United States. In the United Kingdom, the average transport package transport distance is about 300 miles (480 kilometers).

Data on accidents and incidents are kept by individual countries, but there is no standardized reporting format. In the United Kingdom, for example, accidents and incidents have been tracked since 1958 in the Radioactive Material Transport Events Database. Since 1989, annual reports of accidents and incidents have been issued. The latest report reviewed by the committee was issued in 2003 (Watson and Jones, 2004).

Since 1958, there have been 786 incidents involving the transport of radioactive materials in the United Kingdom. Approximately 24 percent of these have involved transport of spent fuel. These range from derailments of the conveyance to incidents involving non-fixed radioactive contamination above regulatory limits on the external surfaces of transport packages (see footnote 14). There have been no reported accidents involving spent fuel transport packages that have resulted in the release of radioactive material from the containment system to the environment.

The most recent significant spent fuel transport incidents in Europe occurred in 1997–1998, when inspections by the French nuclear safety

21  

As noted in Chapter 1, dedicated trains are trains that transport only spent fuel or high-level waste and no other cargo.

22  

As discussed in Chapter 5, decay heat production in spent fuel drops rapidly in the first five years after its discharge from a power reactor; see Figure 5.2.

23  

See, however, Section 5.2.4 for a discussion of the acceptance order for commercial spent fuel to be shipped to Yucca Mountain.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

regulator (Nuclear Installations Safety Directorate) showed that a high percentage of transport packages and conveyances at one reactor and at the rail terminal at Valognes (the receiving terminal for La Hague) contained non-fixed external contamination in excess of regulatory limits. The cause was eventually traced to inadequate decontamination of transport packages after they were loaded with spent fuel at reactors in France, Germany, and Switzerland. There was a three-year moratorium on spent fuel shipments in these countries while the incidents were investigated and new procedures were put into place to eliminate the contamination problems. A subsequent investigation by regulatory authorities concluded that no workers or members of the public had received radiation doses exceeding the relevant regulatory limits as a consequence of these incidents (HSK, 1998).

Two major conclusions can be drawn from the historical record of worldwide transport of spent fuel. The first is that there have been no recorded instances of which the committee is aware of any releases of radioactive material exceeding regulatory limits from any transport package in Western Europe, Japan, or the United States. There are, however, well-documented instances of exposures to radioactivity from inadequate decontamination of the external surfaces of transport packages after they are loaded with spent fuel. However, these releases have been small, and the committee is not aware of any documented instances in which exposures to workers or the public exceeded regulatory limits.

3.1.2 Quantitative Analyses

The AEC and its successor agencies have conducted several assessments of radioactive materials transport risk in the United States. These assessments have used numerical models, informed by expert judgment, to estimate the performance of transportation packages under normal and accident conditions. These studies are summarized in Table 3.6 and are described in this section. Two of these assessments have produced quantitative estimates of risks to workers and members of the public from such transport activities.

The committee was not charged to perform an in-depth technical review of these studies to assess the technical quality of the assumptions, models, results, and uncertainties. The committee does, however, provide comments where appropriate on the assumptions used in these studies and their impact on the resulting consequence estimates. All of these studies have undergone some level of technical review by the issuing organizations, but there are differences in assumptions and approaches among the studies that must be considered when comparing results.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.6 Description of the Analytical Assessments of Transportation Risk Described in This Chapter

Study Reference

Objective

Summary of Results

 

WASH-1238

Estimate doses to workers and public from spent fuel transport

Risks due to radiological effects from transportation accidents are small

AEC (1972)

Transportation EIS

Estimate radiological effects from land, water, and air transport of radioactive materials

Impacts of normal transport and accidents are sufficiently small to allow continued shipments of radioactive materials by all modes

USNRC (1977)

Modal study

Improve understanding of spent fuel package performance under severe accident conditions

Risks from severe accidents involving spent fuel were lower by at least a factor of three than estimated in the transportation EIS

Fischer et al. (1987)

Reexamination study

Update the modal study using improved models and data

Risks from severe accidents are comparable to or lower than modal study estimates

Sprung et al. (2000)

Final Yucca Mountain EIS

Estimate spent fuel and high-level waste shipping risks for transportation of spent fuel and high-level waste to Yucca Mountain, Nevada

Expected transportation impacts are small given the size of the transport program

DOE (2002a)

WASH-1238 Study (1972)

The first analytical study of the health effects of spent fuel transportation in the United States was undertaken by the AEC in 1972 (AEC, 1972). This study is known as the “WASH-1238” study after its report identification number. This study estimated doses to workers and the general public from nuclear fuel and solid radioactive waste transport both under normal transport conditions and for severe accidents. The study’s main conclusion was (AEC, 1972, p. 2) that “[w]hen both the probability of occurrence and extent of the consequences are taken into account, the risk to the environment due to radiological effects from transportation accidents is small.”

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

The study has limited applicability to modern-day spent fuel transport programs: It examined highway transport of spent fuel along routes with very different population densities than present-day routes using transportation packages that do meet current regulatory requirements.

Transportation Environmental Impact Statement (1977)

A transportation Environmental Impact Statement (EIS) was undertaken by the USNRC to evaluate the effectiveness of its regulations for the transport of radioactive materials by air and other modes (USNRC, 1977). This EIS provided a more complete analysis of the radiological consequences for land, water, and air transport of radioactive materials than WASH-1238 and has become the “baseline” analysis for assessing radioactive materials transportation risk in the United States.

The 1977 transportation EIS characterized environmental impacts in terms of fatalities, expressed as an annual probability of occurrence for two types of transport: incident-free transport, where the main health impact is expected to be cancer fatalities due to exposure of workers and the general public to small doses of radiation from the shipping containers; and accidents that produce either conventional traffic fatalities or, for more severe conditions, latent cancer fatalities resulting from the release of radioactive materials from a damaged transport package.

Sandia National Laboratories performed this study. A computer code (RADTRAN 1; Sidebar 3.4) was developed to estimate radiation doses and latent cancer risks of transporting (including temporary storage and modal transfers) 25 different radioactive materials by plane, truck, train, ship, or barge. One of the 25 categories of materials considered was spent power reactor fuel. The study estimated risks to workers involved in shipping the materials and to members of the general public who lived near or traveled on the transportation routes. Latent cancers during incident-free transport were assumed to arise solely from external radiation doses from the transport packages. Latent cancers during accidents were assumed to arise from both internal and external exposure pathways.

The study estimated risks for transport of spent fuel on a generic highway route and a generic rail route. The study provided only a limited consideration of accidents in highly urbanized areas—one analysis was carried out for an accident in New York City. Additional analyses of releases in highly urbanized areas were undertaken in a subsequent series of studies known as the “urban studies” (DuCharme et al., 1978; Finley et al., 1980; Sandoval et al., 1983; Sandoval, 1987). Public circulation of all but one of the unclassified versions of these reports (Sandoval et al., 1983) was restricted after the September 11, 2001, terrorist attacks; consequently, these reports were not available for review by the committee.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

SIDEBAR 3.4
RADTRAN

RADTRAN is a computer code that can be used to estimate radiological exposures and consequences under both incident-free and accident conditions. It can provide estimates of collective dose as well as doses to maximally exposed individuals. The code was first developed by Sandia National Laboratories for use in the 1977 transportation EIS (USNRC, 1977). The code has been expanded and refined several times and is now in version 5 (RADTRAN 5). This code, which is written in FORTRAN 77, is available from Sandia National Laboratories. It has become a worldwide standard for assessing incident-free radiological transportation risks.

The program allows risks to be estimated for seven different transport modes (two highway modes, rail, barge, ship, and two air modes) using a series of models that account for the following:

  • Sources and isotopic contents of transport packages,

  • Transportation routes and stops,

  • Population distributions of workers, residents who live along transportation routes, and vehicle occupants on transportation routes,

  • Number and severity of accidents,

  • Releases of radioactivity from packages in accidents,

  • Dispersion of released radioactivity in the environment,

  • Radiation exposure pathways for inhalation, ingestion, resuspension, cloud-shine, and ground-shine exposures,

  • Radiological fatalities using a dose-response model,

  • Nonradiological fatalities, including vehicular fatalities and fatalities from vehicle emissions.

Like all computer codes, the validity of the results is only as good as the information used as input to the various models and embedded assumptions in the models themselves. Of particular importance in this regard is the input information for population densities, accident numbers and severities, radiation releases, and dispersion in the environment.

INTERTRAN 2 is a development of RADTRAN for international application. It was developed by the Swedish Nuclear Power Inspectorate (SKI) for the IAEA.

The 1977 transportation EIS concluded that the average radiation doses to at-risk populations from radioactive materials transportation were a small fraction of the limits recommended for the general public from all anthropogenic sources of radiation other than medical sources. The USNRC determined that the “environmental impacts of normal transportation of radioactive material and the risks attendant to accidents involving radioactive material shipments are sufficiently small to allow continued shipments by all modes” (USNRC, 1977, p. viii). The Commission concluded that

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

“present regulations are adequate to protect the public against unreasonable risk from the transport of radioactive materials” (46 FR 21629, April 13, 1981).

The applicability of the 1977 transportation EIS for estimating risks for current and potential future transport of spent nuclear fuel is limited, owing mainly to the simple models and limited data used in the analysis. Since the issuance of this EIS, the USNRC has sponsored two additional studies to improve its understanding of the risks from commercial spent nuclear fuel transportation by road and rail. Those studies are discussed in the following sections.

Modal Study (1987)

The modal study (Fischer et al., 1987) was undertaken to improve understanding of spent fuel shipping package performance under severe accident conditions. The study examined the response of generic truck and rail spent fuel packages to both severe impact and fire conditions. As part of the analysis, historical data on real accidents were compiled from government and private databases to develop accident scenarios and their probabilities (see Figure 2.3). The scenarios are displayed as “event trees.” These trees provide a graphic illustration of the sequence of events leading to an accident along with the probability of each event. Each branch of the tree depicts a sequence of events that leads to the accident outcome depicted at the end of the branch. The probability of an accident is equal to the product of the probabilities of each segment along the branch.

Historical data also were used to estimate the magnitudes of impacts and fire loads associated with each scenario. These were calculated from records of accident speeds and angles, the hardness of the objects involved in the impacts, and the frequency and duration of accident-associated fires. A total of 31 truck accident scenarios and 24 train accident scenarios were developed for the analysis. The 1977 transportation EIS, in contrast, defined only eight accident severity categories based on expert judgment.

Analyses were carried out to assess the effects of these accident scenarios on generic rail package and truck packages. The design of these packages was based on analyses of the features of rail packages and truck packages in service at the time of the study and accounted for typical built-in safety margins (see Sidebar 2.4).

The analysis involved a two-stage screening process. Phase 1 screening used dynamic linear and standard transient heat-transfer models to identify those accident scenarios in which the impact and fire conditions would not exceed the regulatory requirements in 10 CFR Part 71 (see Sidebar 2.1). For these scenarios, any releases from the packages are presumed to be below regulatory limits. Approximately 99.4 percent of truck accidents and

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

99.7 percent of the rail accident scenarios analyzed fell into this category (Fischer et al., 1987, p. 9-2).

Phase 2 screening involved more sophisticated analyses of package responses and radiological releases for those accident scenarios that exceeded the 10 CFR Part 71 limits. This screening employed dynamic nonlinear models to estimate package deformation and transient thermal models that took into account the phase change that accompanied the melting of lead shielding at high temperatures. The analyses assumed that the packages contained five-year-cooled pressurized water reactor fuel having a burn-up of 33,000 megawatt days per metric ton, typical of spent fuel for that day.24 The analyses considered breaches of the spent fuel cladding due to both impact and thermal creep (see Sidebar 2.5). The radiological effects considered included releases of radioactive materials from the package as well as increased radiation doses from a loss of package shielding.

Based on the Phase 2 screening, the authors concluded that roughly 0.39 percent of severe accidents involving truck or rail packages would result in radioactive material releases or doses that approached or slightly exceeded the regulatory limits in 10 CFR Part 71. The report concluded that fewer than 0.001 percent of the truck and 0.012 percent of the rail accident scenarios could actually produce hazards that would likely exceed regulatory limits.25 No attempt was made to model the radioactive releases for the most severe accidents, because these conditions pushed the capabilities of modeling programs. Instead, estimates of the releases for these very severe accidents were simply extrapolated from the release behavior during less severe accidents (see Fischer et al., 1987, Table 8.3).

The 1987 study did not include “consequence calculations” to estimate risks to workers and the public from exposure to radiation as was done in the 1977 transportation EIS. However, a comparison of the frequencies and magnitudes of radiological releases from the two studies led the authors of the 1987 study to conclude that their risk estimates for both truck and rail were at least three times lower that those documented in the 1977 transportation EIS (Fischer et al., 1987, p. 9-11). There are several possible reasons

24  

Present-day fuel burn-ups are typically between 50,000 and 60,000 megawatt-days per metric ton. High-burn-up fuel produces more decay heat than low-burn-up fuel of the same age, which has implications for internal package heating in an accident involving fires. However, the generic packages used in the modal study analysis probably would not be suitable for transporting high-burn-up fuel.

25  

To place these numbers in perspective, consider that the planned transportation program to a federal repository at Yucca Mountain by the “mostly rail” scenario (described later in this chapter) would, according to DOE, involve about 9600 rail shipments and 1100 truck shipments (see Table 3.8). Multiplying these shipment numbers by the number of modal study scenarios that result in radiation releases above regulatory limits results in about 0.01 truck release and 1.1 rail releases during the life of the repository transportation program.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

for this difference, including reductions in accident rates in the decade between this study and the 1977 transportation EIS.

Resnikoff (1994, unpublished paper) criticized several aspects of the modal study. These included the transport package designs used in the analyses; the failure to model the end closures of the packages; and the methods and data used to estimate impact and fire conditions. He provides an analysis of 38 severe accidents that he claims shows that the 1977 transportation EIS and 1987 modal study underestimate severe impact and fire conditions and probabilities. He provides his own estimates of releases based on a reanalysis using the RADTRAN 4 code. He concludes that these releases are many times higher than estimated by the 1977 transportation EIS.26 Resnikoff’s analysis prompted Sandia researchers to perform additional historical accident reconstructions (described in Chapter 2), for which they concluded that spent fuel packages would likely maintain their containment integrity in all but possibly the most severe accidents involving long-duration fires.

Reexamination of Spent Fuel Shipment Risk Estimates (2000)

In 2000, Sandia National Laboratories published a reexamination of spent fuel shipment risk estimates (Sprung et al., 2000) using updated models and data. Since this is the most current generic study and has been used as the basis for a more recent analysis of transportation to a Yucca Mountain repository, as discussed later in this chapter, it is described in some detail in this section.

The 2000 reexamination study utilized an updated version of RADTRAN (RADTRAN 5; see Sidebar 3.4) to estimate population doses to workers and the general public during both incident-free transport and severe accidents involving releases of radioactivity or loss of shielding. Estimates were obtained for five potential exposure pathways (direct inhalation, resuspension inhalation, ingestion, cloud shine, and ground shine; see glossary in Appendix D) versus the single direct inhalation pathway considered in the 1977 transportation EIS.

The 2000 study considered transport of spent fuel along 741 truck and 741 rail routes: 249 truck routes and 249 rail routes developed in a previous routing study (Cashwell et al., 1986), as well as 492 truck and 492 rail routes developed specifically for this study. The latter routes connect the 79 spent fuel storage sites in existence when the study was initiated with six hypothetical interim storage sites located in different regions of the United States (474 routes), and those interim storage sites to three hypothetical

26  

The committee did not undertake a detailed review of Resnikoff’s claims.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

permanent repository sites (18 routes). One of the permanent repository sites considered was Yucca Mountain.

To make the analyses tractable, these routes were sampled to obtain a smaller set of routes having representative characteristics. The samples were generated as follows. First, distributions were constructed of route lengths; fractions of those lengths that contain urban, suburban, and rural population densities; and the actual population densities for each of those length fractions for the 741 truck and 741 rail routes. Next, these distributions were sampled using Monte Carlo methods to generate two sets of “representative” routes: 200 highway routes and 200 rail routes. These representative routes were used in the RADTRAN calculations.

The 2000 reexamination study used slightly modified versions of the accident event trees from the 1987 modal study (Figure 3.1). An additional branch was added to the rail event tree to account for accidents involving fires that did not result from either collisions or derailments. Additionally, new estimates of route wayside hardness were developed based on surveys of selected transportation routes and Department of Agriculture data on near-surface locations of coherent rock formations. This information was used to estimate how “yielding” these surfaces would be in accidents involving impacts of truck and rail transportation packages.

Truck and train accident rates used in the study were estimated separately from state-level data for the 48 contiguous U.S. states. These data represent heavy-truck accidents on interstate highways and train accidents on mainline rail routes. The heavy-truck data were detailed enough to support the development of accident rate distributions for suburban and rural routes as well as a single average accident rate for urban routes. The rail data were only detailed enough to support the development of a single accident rate distribution by combining all of the state-level data.

The study modeled the performance of four generic package types whose physical specifications were based on a review of data on packages in use at the time of the study: steel-lead and steel-depleted uranium truck packages and steel-lead and monolithic steel rail packages. The packages were assumed to contain total activities equivalent to three-year-cooled pressurized water reactor (PWR) fuel with a burn-up of 60,000 megawatt-days per metric ton, or three-year-cooled boiling water reactor (BWR) fuel with a burn-up of 50,000 megawatt-days per metric ton. These estimates are characterized in the study as conservative.27 The rail package was

27  

The study characterizes the total activities used in the RADTRAN calculations as being conservative by about a factor of 4. While these high burn-up levels are now achieved routinely in U.S. power reactors, most stored spent power reactor fuel has much lower burn-ups. Moreover, spent fuel is generally expected to be stored for at least five years before being moved from pools to dry casks for storage or transport, and some of it will have been stored for several decades.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

FIGURE 3.1 Accident event trees for rail accidents from the 2000 reexamination study, slightly modified from the modal study (see Figure 2.3). The numbers shown at each branch are probabilities for the accident branch based on an analysis of historical data. The accident scenarios that are marked with an asterisk were determined to produce consequences that would approach or exceed regulatory limits. SOURCE. Sprung et al. (2000, Figure 7.4, p. 7-12).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

assumed to contain 24 PWR or 52 BWR assemblies. The truck package was assumed to contain between 1 and 3 PWR or 2 and 7 BWR assemblies.

External package surface dose rates were also important inputs to the model. These were estimated for commercial spent fuel discharged from reactors in the United States. These dose rates depend on fuel burn-up, time since discharge (or cooling time), and package shielding. For conservatism, the dose rate distribution estimates were rescaled upward so that their upper limits were equal to the regulatory dose limit of 0.1 mSv (10 mrem) at 2 meters (about 6.5 feet) from the package surface.

Analyses of package behavior in severe accidents were carried out using a standard finite element code (PRONTO 3D). This computer code is commonly used to model high strain rates in nonlinear materials. Although material failure is not included explicitly in this code, such failure can be estimated based on the calculated deformation of package components such as lid bolts. This code was used to estimate package deformations resulting from impacts onto unyielding surfaces (see Sidebar 2.2) at speeds of 30, 60, 90, and 120 miles per hour (48, 96, 144, and 192 kilometers per hour). To make the results conservative, the impact limiters were assumed to be attached to the package but fully crushed before impact.

The analyses indicate that even at the highest of these impact speeds, strains were well below the levels needed to fail or penetrate the package body or lid. The analyses also indicate that the truck package seals would not fail in any impact orientation at any impact speed. Nevertheless, it was arbitrarily assumed that seal leaks having a cross section of 1 square millimeter would result from impacts of these packages onto unyielding surfaces at speeds of 120 miles per hour (193 kilometers per hour). The analyses also suggest that for rail packages, some seal leakage could occur for some impact orientations at impact speeds onto unyielding surfaces as low as 60 miles per hour (97 kilometers per hour) and possibly at all orientations at speeds of 120 miles per hour (193 kilometers per hour).

Surfaces along transportation routes (e.g., soils, concrete structures) are likely to be partially yielding and will absorb some impact energy in severe accidents. Consequently, the finite element results for impacts onto unyielding surfaces must be adjusted to account for this energy loss. This was done by calculating the impact speeds onto three types of yielding surfaces (soil, concrete, hard rock) that would result in the same peak contact forces on the package as the equivalent impact onto an unyielding surface. This calculation took into account the energy-absorbing effects of the package impact limiters.

If the package seal was determined to fail in an accident, the release of radioactive material (noble gases, volatiles, and particulates), collectively referred to as the accident source term, was calculated. These calculations took into account several phenomena: rod cladding failures; radionuclide

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

inventory releases from the failed rods; partial deposition of radionuclides on internal surfaces in the package; pressurization of the package interior from failed rods or package heating; and leakage of radionuclides through package seal failures driven by package depressurization (see Sidebar 2.5). The estimates of particulate releases and behavior were based on actual experiments performed on spent fuel rods subjected to burst failure.

For accidents involving fires, package heating calculations were carried out using a commercial code (PATRAN/PThermal), which can be used to model heat convection, conduction, and radiation transport processes. Calculations were made for each of the four generic packages for a fully engulfing, optically dense hydrocarbon fire that would heat the package sufficiently to cause the pressurized rods to fail by burst rupture. The calculations included the effects of internal package heating from radioactive decay of three-year-cooled spent fuel.28 Package seal leakage and accident source terms were estimated in a manner similar to that described previously for severe accidents.

Several sets of RADTRAN calculations were performed in this study:

  • Calculations for the 200 truck and 200 rail routes obtained by Monte Carlo sampling as described previously;

  • Calculations for 5 truck and 5 rail routes selected from the 1977 transportation EIS or from the 474 routes that connect spent fuel storage sites to the locations of the hypothetical interim storage facilities considered in this study—the latter calculations were carried out to demonstrate that results for real routes would fall within the envelope of results for the representative 200 rail and 200 truck routes;

  • Calculations comparing the consequences and risks for RADTRAN 1 with RADTRAN 5 for a single transportation route; and

  • Calculations comparing the risks and consequences using the package inventories and assumptions about radionuclide releases developed for the 1977 transportation EIS, 1987 modal study, and this study.

The study provided RADTRAN calculations for both incident-free and severe accident scenarios. The conservative assumptions used in these analyses (e.g., the packages contain three-year-old spent fuel with high burn-ups; the external package dose rate distribution estimates were rescaled upward so that their upper limits were equal to the regulatory dose limits; package

28  

The use of three-year-cooled spent fuel in the calculations yielded external steady-state package surface temperatures as high as 194°C (Sprung et al., 2000, Table 6.4). This would have exceeded the regulatory limits in 10 CFR 71.43(g), which restricts external surface temperatures to 85°C for exclusive-use shipments. The authors described these temperatures as “conservative” for the purposes of the analysis.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

deformation estimates were made using fully crushed impact limiters; truck package seals were assumed to have small leaks at high-impact speeds even though the analyses did not indicate seal failure) are reasonable for producing bounding estimates of accident consequences or radiological exposures. However, the 200 rail and 200 truck routes selected through Monte Carlo techniques for use in the analyses were based on realistic, not bounding, characteristics. Consequently, the overall results of the Sandia analyses are likely to be neither realistic nor bounding and probably overestimate the transport risks.29

One result is discussed below for the sake of illustration: Population risk estimates for severe accidents involving rail transport of PWR spent fuel in a steel-lead rail package. This example was selected because PWR fuel is the most common fuel used in U.S. power reactors and because train transport is the preferred mode for shipping to a federal repository and to Private Fuel Storage (see Chapter 2).

The population risk estimates for each of the 200 route calculations for the rail package are displayed as complementary cumulative distribution functions (CCDFs), which are also sometimes referred to as “risk curves” (Figure 3.2). The horizontal (x-axis) is referred to as the accident consequence value. Simply put, this is the collective dose that would be received by the population defined in the model as a result of the assumed accident scenario calculated by the model. The vertical (y-axis) is the probability that the collective dose will exceed that accident value on a per-shipment basis. This probability is given in dimensionless units ranging from 0 to 1. The right vertical axis is the expected number of years between accidents exceeding the accident consequence value when 100 shipments per year are assumed.

The total set of 200 CCDFs would produce a plot like that shown in the inset in Figure 3.2. To improve the visual utility of such plots, compound CCDFs can be constructed that represent certain statistical properties of the 200 individual CCDFs. For the compound CCDFs shown in Figure 3.2,

  • The mean compound CCDF is computed by averaging the 200 CCDFs;

  • The 50th percentile compound CCDF represents the median value of the 200 CCDFs; and

  • The 95th and 5th percentile compound CCDFs represent the 190th highest and 10th lowest of the 200 CCDFs.

29  

The committee hedges this statement with the word “probably” because there are a great many other uncertainties in the input data to the calculations, especially with respect to local accident rates and route wayside conditions, that could affect the realism of the calculations.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

FIGURE 3.2 Compound CCDF (complementary cumulative distribution function) for train transport of PWR fuel using steel/lead packages. The left vertical axis is the probability expressed on a per-shipment basis; the right vertical axis represents the expected years between accidents assuming 100 shipments per year. Inset: Plot showing individual CCDFs for 200 routing calculations of the type used to derive the compound CCDFs shown in the main figure. SOURCE: Sprung et al. (2000, Figure 8.7).

Two general observations can be made from this plot. First, the estimated risk of exposure from an accident that is severe enough to compromise fuel rod and package seal integrity is very small on a per-shipment basis. For example, the expected (mean) probability of receiving a population dose of 1 person-rem (i.e., 100 person-rem in the figure) is about 1 in 100 million (10−8) per package shipment. Assuming a shipment frequency of 100 packages per year, the expected mean time between such accidents is estimated to be about 1 million years.

Second, the spread of probability (left vertical axis) values of the compound CCDFs at a given consequence value (horizontal axis), which is represented by the vertical distance between the 5th and 95th percentile compound CCDFs, reflects the sensitivity of the calculations to route characteristics (e.g., route length, wayside hardness, traffic conditions). The variability is about an order of magnitude at low consequence values and increases to more than 5 orders of magnitude at high consequence values.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

The collective dose risk30 for all of the RADTRAN 5 calculations displayed in the figure is equal to 9.4 × 10−6 person-rem on a per-shipment basis. If an accident has a 1 in one million probability of occurrence (i.e., 1 × 10−6), the mean collective dose received by the population (the size of which must be specified) would be about 9 rem per accident. The mean collective dose risks are most useful as a tool to compare different accident risks as shown in Table 3.7.

The population (collective) dose risks for all of the packages modeled in the 2000 reexamination study are shown in Table 3.7. The authors of this study also calculated the collective dose risks using the source terms from the 1977 transportation EIS and the1987 modal study. Two observations are particularly noteworthy. First, estimated population dose risks for the reexamination study are on the order of 10−6 to 10−7 person-rem per shipment for all of the packages and scenarios examined in the study. Given the uncertainties in the parameters used in the calculations, these values are essentially identical. Second, estimated population dose risks from the 2000 reexamination study are about three orders of magnitude lower than estimates calculated using the source terms in the1977 transportation EIS and the 1987 modal study. These differences are probably significant and may reflect a lack of realism in some of the assumptions used in the earlier analyses, especially with respect to package release behavior in a severe accident. As noted previously, this behavior was based largely on expert judgment in the 1977 transportation EIS. Release behavior was modeled explicitly in the 2000 reexamination study.

Final Yucca Mountain EIS (2002)

DOE has prepared an EIS (DOE, 2002a) as part of a larger effort to site and construct a federal repository for spent fuel and high-level waste at Yucca Mountain, Nevada. This EIS provides estimates of spent fuel and high-level waste transportation risks. The EIS considers two scenarios for transporting spent nuclear fuel and high-level radioactive waste from 72 commercial and 5 defense sites to the proposed repository at Yucca Mountain, Nevada: a mostly truck scenario that would involve transporting most of the spent fuel and high-level waste by legal-weight truck across the

30  

The mean collective dose risk is the collective dose that is received by the population from an accident times the probability of occurrence of that accident. This follows from the general risk equation, risk = probability x consequences, where consequences = collective dose. The collective dose is conditional because it will be received only if the accident occurs. In that case, the collective dose can be calculated by dividing the risk by the probability that the accident will occur, or consequences = risk ÷ probability. The mean collective dose risk is most useful as a comparative tool.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.7 Population (Collective) Dose Risks for Severe Accidents from the 2000 Reexamination Study

Package Type

Population Dose Risk (person-rem)a

Truck

Rail

PWR

BWR

PWR

BWR

2000 reexamination study

 

Steel-lead

8.0 × 10−7

3.3 × 10−7

9.4 × 10−6

9.2 × 10−6

Steel-DU

2.3 × 10−6

1.1 × 10−6

 

Monolithic steel

 

2.0 × 10−6

1.5 × 10−6

Calculated using 1977 transportation EIS and 1987 modal study sources terms

1.3 × 10−2 to 1.3 × 10−4

 

1.9 × 10−2 to 4.9 × 10−4

 

NOTE: Numbers are rounded to two significant figures; BWR = boiling water reactor; DU = depleted uranium; PWR = pressurized water reactor.

aExpected values per shipment.

SOURCE: Sprung et al. (2000, Tables 8.4, 8.5, E.2).

nation’s highways, and alternatively, a mostly rail scenario that would involve transporting most of this material using commercial railroads and a railroad spur to be constructed in Nevada. The numbers of truck and rail shipments under each scenario are shown in Table 3.8.

DOE considered the impacts of two repository scenarios in this EIS. The first assumes that Yucca Mountain would receive the legislatively mandated limit of 70,000 metric tons of spent fuel and high-level waste over a period of 24 years. The second assumes that the repository would operate for 38 years and would receive between 119,000 and 125,000 metric tons of spent fuel, high-level radioactive waste, and other special requirements waste (e.g., greater-than-class-C waste).

DOE’s analysis of transportation impacts examined several classes of hazards for workers and the general public, two of which are of particular interest in this discussion:

  1. Incident-free transportation in which populations in proximity to transportation routes would receive small radiation doses during the routine transport of spent fuel and high-level waste. These doses would be the result of radiation shine from the transport packages.

  2. Accidents that involve a loss of transport package shielding, which could result in more severe radiological exposures. The EIS analyzed a

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.8 Transportation Scenarios, Collective Doses, and Radiological Impacts from the 2002 Yucca Mountain Repository EIS for Routine Transport and Accidents

 

Mostly Truck Scenario

Mostly Rail Scenario

Comment

Scenario Definitions

Operational period (years)

24

 

Repository capacity (MTHM)

70,000

Number of legal-weight truck shipments

 

Commercial SNF

41,000

1100

 

DOE SNF

3500

 

DOE HLW

8300

Number of rail shipments

 

Commercial SNF

300

7200

 

DOE SNF

 

770

DOE HLW

 

1700

Radiological Impacts, Routine Transporta

Worker collective dose (person-rem)

29,000

7900–8800

Collective dose received over 24 years assuming specified crew sizes for loading, transport, and inspections; total numbers of workers not specified

Dose to maximally exposed worker (rem)

48

48

Assumes that worker receives the DOE occupational administrative dose limit of 2 rem per year for 24 yearsb

Estimated number of worker latent cancer fatalities

12

3.2–3.5

 

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

 

Mostly Truck Scenario

Mostly Rail Scenario

Comment

Dose to maximally exposed member of the public (rem)

2.4

0.29

Maximally exposed person for mostly truck is a service station worker; mitigation would be required to keep doses below 0.1 mSv (100 mrem) per year. Maximally exposed person for mostly rail is resident near a rail stop

Public collective dose (person-rem)

5000

1200–1600

Distributed across 10.4 million people for mostly truck scenario and 16.4 million people for mostly rail scenario over 24 years

Estimated number of public latent cancer fatalities

2.5

0.6–0.8

 

Total estimated number of latent cancer fatalities

14

3.8–4.3

Radiological Impacts, Maximally Reasonably Foreseeable Accident (MRFA)c

Accident scenario

Long-duration fire that leads to breach of a package and dispersal of a portion of its contents

Long-duration fire that leads to breach of a package and dispersal of a portion of its contents

 

Annual probability that the accident will occur

2.3 in 10 million

2.8 in 10 million

During each year of the 24-year shipping campaign

Dose to maximally exposed individual assuming the accident does occur (rem)

3

29

Maximally exposed individuals are located downwind of the package and receive dose from a cooling plume of radioactive particles released from the package

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

 

Mostly Truck Scenario

Mostly Rail Scenario

Comment

Collective dose assuming the accident does occur (person-rem)

1100

9900

Analysis assumes that the accident occurs in an urban area, and that populations up to 50 miles (80 kilometers) from the release point could receive a dose. Population densities used in the calculations were based on 1990 census data extrapolated to 2035 for 21 large urban centers in the United States. Accident was assumed to occur at the center of the population zone

Total number of latent cancer fatalities assuming accident does occur

0.6

5

Calculated by multiplying the collective dose by the nominal probability coefficient

Annual collective dose risk (rem)

2.5 × 10−4

2.8 × 10−3

See footnote 30

Nonradiological Impacts

Total fatalities from vehicular collisions, industrial accidents, and air emissions

6.8

3.1–4.2

 

NOTE: Numbers are rounded to two significant figures.

aThe dose estimates shown in this section of the table have a probability of occurrence of 1; that is, it is certain that these doses would be received by workers and members of the public if the Yucca Mountain transportation program were carried out as described in Appendix J of the final Yucca Mountain EIS.

bThe final Yucca Mountain EIS also notes that if a lower administrative dose limit is imposed on transportation workers in the future, maximally exposed worker doses would be correspondingly lower.

cDose estimates shown in this section of the table are conditional upon the actual occurrence of the accident, which has a very low probability of occurrence.

SOURCES: DOE (2002a, Table 6-1, Table J-1, Table J-16, table on p. S-69, table on p. S-80).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

“maximum reasonably foreseeable accident”31 to provide some perspective on the largest expected transportation impacts on populations that live along potential transportation routes. The EIS analyzed the consequences of accidents that are expected to occur with a frequency greater than 10−7 (i.e., with a likelihood greater than 1 in 10 million times per year).

The EIS estimated the consequences of these hazards to several groups of individuals: workers involved in loading, transporting, inspecting, and escorting the shipments; members of the public in vehicles that share transportation routes with the shipments; members of the public who live in proximity to transportation routes; and members of the public who are exposed while shipments are stopped en route to Yucca Mountain.

Appendix J of the final Yucca Mountain EIS provides a detailed discussion of the models, data, and assumptions that were used to produce these estimates. In developing these analyses, DOE used the RADTRAN 5 code developed by Sandia National Laboratories (see Sidebar 3.4) for estimating collective radiological doses under both incident-free and accident conditions. DOE relied heavily on the accident scenarios and the transport package release mechanisms developed in the 2000 reexamination study. The RISKIND32 computer code was used to calculate radiological doses to

31  

According to DOE, maximally reasonably foreseeable accidents are characterized by extremes of mechanical and thermal forces, and other conditions not specified, that lead to the “highest reasonably foreseeable consequences” (DOE, 2002a, p. 6-45). The thermomechanical forces in these accidents would exceed regulatory limits and would be applied to a package in such a way as to cause the greatest damage and would lead to the release of radioactive materials. DOE defines any accident that has the chance of occurring more than 1 in 10 million times per year as being reasonably foreseeable. The Final Yucca Mountain EIS analyses of maximally reasonably foreseeable accidents were based on an examination of the accident scenarios presented in the reexamination study (Sprung et al., 2000). The analyses are described in Appendix J of the EIS. The scenario determined to be most severe for both rail and truck packages is a long-duration fire.

32  

The RISKIND code was developed in 1993 by Argonne National Laboratory to estimate local, scenario-specific radiological doses to maximally exposed individuals. This code performs similar calculations for incident-free exposures as the RADTRAN code. However, the two codes use different mathematical representations for external dose rate as a function of the distance between the source and receptor (Steinman and Kearfoot, 2000). Steinman et al. (2002) compared the estimates from these models against experimental measurements on moving conveyances containing radioactive materials. They found that both the RADTRAN and the RISKIND models predict doses to within an order of magnitude of the experimentally measured values. The RISKIND model estimates agreed more closely with the measured values at short distances (within a few meters) from the package, whereas RADTRAN provided better agreement at distances that the authors characterized as more typical of residential populations alongside of roads.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

maximally exposed individuals for incident-free transportation and to populations and maximally exposed individuals for maximally reasonably foreseeable accident conditions.

To make incident-free radiological impact assessments, DOE assumed that each transportation package would have the maximum external dose rate allowed under DOT transport regulation 49 CFR 173.441(b) (as well as USNRC regulation 10 CFR 71.47(b)(3)): 0.1 mSv per hour (10 mrem per hour) at 2 meters (6.5 feet) from the lateral surfaces of the transport vehicles. This is a conservative assumption when the packages contain aged spent fuel.33

Estimates of the number of shipments were based on information on current inventories of spent fuel at reactor sites as well as projections of future inventories based on industry trends. The analysis took into account factors such as package handling capabilities34 at each site and package capacities to meet heat generation and criticality requirements. In some cases, these requirements would necessitate the shipment of partial packages. The analysis used 31 shipping package configurations: 9 for legal-weight truck and 22 for rail.

Highway routing selections were made using actual highway data and DOT rules for Highway Route-Controlled Quantities of Radioactive Materials in 49 CFR 397.101. Population densities within 800 meters (0.5 mile) of the routes were used to calculate incident-free doses.35 These densities used data derived from the 1990 and 2000 census data and were extrapolated to the year 2035 based on Bureau of the Census forecasts.

Rail routing selections were made using rules based on the historical routing practices of U.S. railroads from a database of 94 rail networks representing current railroad conditions. Rail routes were determined by minimizing shipping “impedance,” which is accomplished by reducing travel distances and the number of railroad companies involved and by using main line (i.e., generally better maintained) tracks. Population densities within 800 meters (0.5 mile) of the routes were used to calculate incident-free doses. These densities used data derived in the same manner as for highway shipments. Route selections were made for all but six sites that do not have the capacity to load or handle rail packages.

33  

However, as discussed in Chapter 5, the first fuel shipped to Yucca Mountain might not be thermally and radiologically cool.

34  

For the mostly rail scenario, the analysis assumed that sites that had insufficient crane capacity to handle rail packages would be upgraded after the plant shut down.

35  

Calculating doses out to 800 meters is a very conservative approach. If the dose rate at 2 meters (6.5 feet) is 0.1 mSv per hour (10 mrem per hour), then the dose rate at 800 meters (0.5 mile) is 6.25 x 10−7 mSv per hour (6.25 x 10−5 mrem per hour). This is a negligible exposure and becomes trivial when the conveyance is moving.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

For the mostly truck scenario, DOE assumed that all shipments would be made by legal-weight truck except for naval spent fuel, which would be shipped by rail. For the mostly rail scenario, DOE assumed that all sites would ship by rail except for the six commercial sites that do not have the capability to load rail packages. DOE assumed that these sites would ship by legal-weight truck until the sites shut down. They would then be upgraded to load rail packages and would ship by direct rail (or heavy-haul truck or barge). Another 24 commercial sites that do not have rail access would ship by heavy-haul truck or barge to railheads.

Table 3.8 provides a summary of the EIS analyses for Yucca Mountain for a 24-year transportation program involving the movement of 70,000 metric tons of spent fuel and high-level waste to the repository. The table provides several types of consequence estimates:

  • Estimates of radiation exposures during incident-free transport. Two types of exposures are estimated: the collective dose (see Sidebar 3.3) to workers and to members of the public during incident-free transport, and doses to the maximally exposed worker and member of the public.

  • Estimates of the annual probabilities of the maximally reasonable foreseeable accident.

  • Estimates of collective doses and the maximally exposed individual if the maximally reasonably foreseeable accident does occur.

  • Estimates of latent cancer fatalities from these exposures calculated as described in Sidebar 3.3.

  • Estimates of the annual collective dose risk.

For comparison purposes, the estimated number of fatalities from nonradiological exposures are given at the bottom of the table. These fatalities are estimated to arise from vehicular collisions, industrial accidents during loading and handling of the transport packages, and air emissions from the transport vehicles.

Several observations from Table 3.8 are noteworthy. First, and perhaps most important, a Yucca Mountain transportation program will not be risk free. Workers and members of the public who are exposed to radiation from the transportation packages could have an elevated risk of developing fatal cancer. However, the absolute risk, as measured by the total number of fatalities, will be very small for either rail or truck transport for both incident-free and accident scenarios.

It is important to recognize that these risk estimates are based on a large number of parameter estimates having varying degrees of uncertainty. In view of these uncertainties, it is unclear whether the estimates of radiological fatalities for either the mostly truck or the mostly rail scenarios are significantly different. Also, the estimates of fatalities represent averages for

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

all shipments over all routes. There may be individual routes, shipments or persons that could have risks that are significantly higher or lower than those shown in Table 3.8.

The maximally foreseeable reasonable accident probabilities are similar for both truck and rail accidents (on the order of 10−7 occurrences per year [i.e., 1 occurrence every 10 million years]). This is a very low recurrence rate compared to other kinds of transportation accidents that result in the release of hazardous materials to the environment. The collective dose estimates shown in Table 3.8 are also based on some conservative assumptions: for example, the accidental releases are assumed to occur at the center of a large urban area having a population density extrapolated to 2035. Also, the collective doses are calculated out to a distance of 50 miles (80 kilometers) from the release point and would include large numbers of people who receive very small doses. The resulting collective dose risks shown in the table (2.8 × 10−3 to 2.5 × 10−4) reflect these conservative assumptions.

It is worth emphasizing the differences between the dose estimates shown in Table 3.8 for incident-free transport and the maximally reasonably foreseeable accident. The incident-free estimates have a probability of occurrence of 1 (i.e., the hazard is always present during transport) if the transportation is carried out as described in Appendix J of the final Yucca Mountain EIS (DOE, 2002a). The dose estimates for the maximally reasonable foreseeable accident, on the other hand, are conditional on the occurrence of that accident. The probability of occurrence of such an accident is estimated to be very low, on the order of 1 chance in 10 million each year the program is in operation. This is a very low probability, so these doses are very unlikely ever to be received by workers or the public. This low probability is reflected in the small collective dose risk estimates shown in the table.

The State of Nevada provided extensive commentary on the Yucca Mountain draft EIS estimates of transportation risk (Nevada, 2000). The state believes that incident-free transportation risks based on truck transport have been underestimated and that the models and scenarios used for the accident consequence estimations are also unrealistic, echoing earlier criticisms by Resnikoff (1994). As noted previously, the final EIS for Yucca Mountain relied heavily on the data and modeling approaches used in the 2000 reexamination study. The State of Nevada has criticized this approach because the 2000 study was performed by a contractor and was not subjected to the public review and comment process used for the 1977 transportation EIS.

Some participants at the committee’s information-gathering meetings suggested that the accident statistics used in these analytical studies needed to be reanalyzed in light of increased truck traffic and vehicular speed limits

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

on interstate highways. Participants also raised concerns about whether these studies have appropriately analyzed the consequences of the very low frequency but high-magnitude accident scenarios that could result in releases from spent fuel packages.

The committee has not performed an in-depth analysis of the methods used in the final Yucca Mountain EIS to estimate the radiological impacts shown in the table. The calculation of maximum incident-free impacts can be made if reliable data on shipments, routes, and populations can be obtained. The State of Nevada’s specific concerns about incident-free exposures for the mostly truck scenario would have limited relevance for a mostly rail scenario, which DOE has announced as its preferred scenario for shipments to a federal repository. Many fewer total shipments would be required under this scenario (see Table 3.8), and in general there are likely to be greater distances between packages and members of the public along main line railways. To the extent that truck shipments are made under this scenario, however, the likelihood of exposure to radiation will depend to a great extent on the routing of these shipments through populated areas. Since routing decisions have not yet been announced, the committee cannot evaluate these potential impacts.

3.2 SOCIAL RISKS

As defined by the committee, social risks arise from both social processes and human perceptions (see footnotes 1 and 2 in this chapter). They can arise during the construction of transportation facilities, during routine transportation operations, and as a result of transportation accidents. Social risks are associated with the two types of impacts shown in the right-most column of Table 3.1: direct social and economic (i.e., socioeconomic) impacts,36 and perception-based impacts. These two types of impacts can be difficult to separate in practice because they can have similar manifestations, as described below.

A number of direct socioeconomic impacts can result from the transport of spent fuel and high-level waste. Routine transport operations, for example, might result in increased visual impacts (i.e., increased numbers of visually conspicuous shipments of spent fuel through communities), especially from large-quantity shipping programs at the “funnel end” of a transportation system where large numbers of conveyances would be expected to travel along a single route. These activities may have direct impacts on

36  

These kinds of “standard” socioeconomic impacts are included as factors that must be considered in environmental impact statements under the National Environmental Policy Act: for example, see Chapter 8 of the final EIS for Yucca Mountain (DOE, 2002a).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

quality of life, property values, and/or business activities, especially if they persist over extended periods of time. Severe accidents involving loaded transportation packages might lead to the temporary loss of use of a transportation route, which could result in business disruptions and other inconveniences with economic and quality-of-life impacts.

These direct socioeconomic impacts arise from generally well understood social processes. For example, most people prefer to live in neighborhoods with roads that carry low volumes of mostly local vehicular traffic. Such neighborhoods tend to be quieter and safer for unsupervised children. The preference for such neighborhoods is reflected by their higher property values compared with nearby neighborhoods along major roads. Similarly, most people prefer to shop at stores that offer easy access by foot, public transportation, or (in most suburban areas) automobile. People will tend to avoid stores along highly congested routes if comparable but more easily accessible alternatives are available. These preferences are examples of social processes in action.

Perception-based impacts arise from people’s beliefs and values concerning the consequences of transportation activities on their well-being and that of their communities (Sidebar 3.5). Such perceptions can shape

SIDEBAR 3.5
Well-being and Social Risk

The general proposition that peoples’ well-being changes systematically as events interact with beliefs and values has been central to economic and social theories for generations. Broadly speaking, these processes take place around us (and to us) continuously. Except for truly isolated hermits, people’s well-being is inevitably affected by the behavior of others; this is why being treated respectfully so often matters, cell phone use is unwelcome in concert halls, and social ostracism hurts.

Social rules governing behaviors that affect people’s well-being are often informal and subject to change over time (this explains why Ann Landers, an expert in informal rules governing behaviors that impinge on the well-being of others, had such a hugely successful career). When there is broad agreement that a behavior damages the well-being of a sufficient number of others, it is often proscribed by formal rules: Noise ordinances in some cities preclude the too-enthusiastic sharing of music, zoning rules forbid certain kinds of property use, nudity is illegal in most public places, and smoking is heavily regulated. Many arguments can be (and are) made about the nature and extent of the losses associated with these behaviors, but in common they reflect a sense of lost well-being on the part of affected people. The bottom line remains that in a representative political system, if enough people perceive a loss of well-being, rules regulating the offending behavior are likely to be forthcoming.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.9 Examples of Impacts of Social Risks

Social Risk Impacts

Reference Examples

Increased stress and anxiety (psychosocial risks)

NCRP (2001); Slovic (2001a,b); Tuler (2002); Webler (2002)

Loss of sense of security and safety

NCRP (2001); Slovic (2001a,b); Williams et al. (1999)

Loss of trust and confidence in government and government agencies

Freudenberg (1993); Slovic (1993); Satterfield and Levin (2002); Tuler (2002); Rosa and Clark (1999)

Reduced desirability as a place to live

Hunsperger (2001); Slovic et al. (2001)

Reduced economic activity (e.g., tourism and other business activities)

Easterling (1997); Easterling and Kunreuther (1993); Hunsperger (2001); Slovic et al. (2001); UER (2001, 2002)

Reduced property values

UER (2000); Gawande and Jenkins-Smith (2001); Hunsperger (2001)

peoples’ behaviors and can materially affect both individual and community welfare.37 The impacts of social risks may be manifested in different ways, ranging from stress or depression to more direct socioeconomic impacts including losses in jobs or wealth and to sociopolitical impacts that include loss of institutional trust, but in common they result from the ways in which people understand and then respond to the effects of a hazard on their well-being.

While these perception-based impacts can produce a systematic reduction in people’s sense of well-being (or utility), the mechanism of loss can vary. Table 3.9 provides examples of some of the potential consequences resulting from actual or feared exposures to radioactive materials or beliefs about the ways such materials are managed. Previous research suggests that while such consequences may result from concerns about radiation, these kinds of consequences are not guaranteed to result; the social dynamics of how perceptions and consequences emerge is complex and incompletely understood.

Perception-based impacts arise in many different contexts. With respect to a spent fuel and high-level waste transportation program, risks might arise as follows. The advent of a program for transporting spent fuel and high-level waste—perhaps even in the planning stages—might produce im-

37  

Another term used to describe these effects is “special impacts.” Appendix N of the final EIS for Yucca Mountain (DOE, 2002a) includes a section that evaluates these potential impacts.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

agery and messages (i.e., signals) about the program’s impacts on local communities (Slovic et al., 1991). The signals originate from an array of sources, including the program’s implementing organization, opposition groups, government agencies, and others. These signals are typically transmitted to individuals though the news media (Kasperson et al., 1988), but also through public meetings and government reports.

These signals are discerned (filtered, interpreted, and evaluated) by members of affected communities in light of their prior beliefs and values (Jenkins-Smith and Smith, 1994). Given that signals and images of nuclear waste are usually very negative (Slovic, 1987; Slovic et al., 1991), it is not surprising that the prospect or advent of a transport program through a community may widely be perceived to be threatening.

The discernment of a threat posed by spent fuel and high-level waste shipments—regardless of whether it is consistent with technical estimates of risk—has real implications for affected individuals. The threat can diminish individuals’ sense of well-being, sometimes in an acute manner, as the understood threat undermines health expectations and increases emotional and physical stress (MacGregor and Flemming, 1996; but see Renn, 1997). The sense of loss can be exacerbated by a sense that the imposition of the risk is unjust or inequitable. When a community—for example, a low-income or minority community—has historically been subjected disproportionately to harms emanating from industrial and other undesirable activities, is less endowed with the resources needed to manage the risks, or holds values that are unusually susceptible to infringement by additional discerned threats (e.g., cultural or spiritual beliefs attached to a place), the loss is likely to be seen as unjust.

This “substantive” injustice can also be matched by “procedural injustice”: that is, a sense of injustice stemming from the belief that the process by which the threat was imposed is unfair (Gusterson, 2000). The losses potentially associated with a pervasive sense of injustice are numerous and may include loss of trust in government institutions, reduced faith that citizen involvement can result in appropriate public policy (i.e., a sense of disempowerment), and a reluctance to participate in planning processes (e.g., public meetings) (Kasperson, 1983; Fischer, 2001; Bradbury et al., 2003).

Federal (e.g., EO, 1994; CEQ, 1997; EPA, 1998a; DOE, 1995a; DOT, 2002), some state (American Bar Association, 2004) and city governments, and a growing number of other organizations (e.g., NCHRP, 2004) have recognized the importance of environmental justice38 impacts, and some

38  

Environmental justice is the fair treatment and meaningful involvement of people regardless of race, gender, national origin, or level of attained education in the development of laws, regulations, and policies that affect them (see IOM, 1999).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

have enacted laws, regulations, and policies to address them. Additionally, a rich literature on environmental justice has developed over the past 20 years (e.g., GAO, 1983; United Church of Christ, 1987; Bullard, 1990a,b; Bryant and Mohai, 1992). It has many thrusts, such as identifying and characterizing the causes of disproportionate harms (Adeola, 1994), often through community-based participatory research (Shepard et al., 2002); investigating the effects of scale of measurement (e.g., census tract, block group) on disproportionate impacts on communities (Eady, 2003); and developing mitigating tools, such as good neighbor and community benefits agreements.

Should the perceived threat become broadly associated with a place or community, it could have a potentially lasting stigmatizing39 effect (Kasperson et al., 2001; Slovic et al., 2001). For spent fuel and high-level waste shipments, concern about stigma would be associated chiefly with severe accidents, but it could also result from frequent and widely publicized shipments or minor vehicular accidents involving spent fuel or high-level waste shipments.

Publicity about transportation incidents, even minor incidents, can result in the social amplification of risk in which “the consequences of risk and risk events … often exceed the direct physical harm to human beings and the ecosystems to include more indirect effects on the economy, social institutions, and well-being associated with the amplification-driven impacts” (Kasperson et al., 2001, p. 18; see also, Slovic et al., 1991). Discerned risks from hazards such as spent fuel and high-level waste shipments also can change behaviors. A perceived threat to health may modify the way people use residential properties (Berrens et al., 2002) or change the attractiveness of areas for residency, vacations, and conferences (Easterling and Kunreuther, 1993).

Changed perceptions of places resulting from discerned threats may result in changes in perceived values of residential and commercial properties (Ketkar, 1992; Mendelsohn et al., 1992; Kiel, 1995; Hunsperger, 2001). These perceived losses may translate into reductions in market values as sellers become more eager to leave and buyers more wary of the affected locale.

Because perception-based impacts derive from the manner in which individuals recognize and understand the hazard, social risks are sometimes mistakenly treated by technical experts and policy makers as imaginary, or less real, than the health and safety risks discussed in Section 3.1. The general difficulty in quantifying social risks no doubt contributes to this

39  

Stigma marks a person, place, product, or technology as deviant, flawed, or undesirable. When the particular stigmatizing characteristic is observed, the person, place, product, or technology may be denigrated or avoided.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

view. Nevertheless, it is clear from social science research, some of which is described in the next section of this chapter, that social risks are as real and important to many people as the associated health and safety risks. They can impact individuals and communities in ways other than injury or death. In addition, social risks may exacerbate concerns about the likelihood of future, unanticipated health and safety risks. For example, an erosion of trust in a program or the agency overseeing such a program can arise from frequent minor problems; these continuing problems may lead people to conclude that the agency lacks the capacity to effectively manage the program over the long term. Left unaddressed, these risks could diminish the ability of implementers to mobilize the necessary resources for managing the health and safety risks of transportation systems.

Technical experts and policy makers sometimes attribute the concerns about social risks expressed by others as based on misinformation about or ignorance of the “real” (i.e., health and safety) risks. This attribution is frequently coupled with calls for better public education about risk, with the unspoken implication that such education would encourage the public to behave more rationally (i.e., more like technical experts). Although there is no doubt that the public would benefit from more accurate information about transportation risks, one should not expect that such information would result in a widespread change of public behavior. Such “information deficit” approaches to behavior change have largely been discredited (e.g., Kollmuss and Agyeman, 2002).

In fact, people may be acting rationally if they oppose spent fuel and high-level waste transportation on health and safety grounds even if they agree with the experts that the estimated health and safety risks are low. Most people recognize that transportation programs are run by fallible institutions and that institutional and human errors play a large role in determining transportation risks. There are many examples of technological systems where the experts were wrong or overly optimistic (Schrader-Frechette, 1995; Perrow, 1999; Freudenburg, 2003). They also recognize that the risk of an accidental release from a spent fuel shipment, while low, is not zero and, moreover, that such a release can have a range of consequences: health, safety, and social. Rational people care about all consequences that can impact their lives and communities, not just health and safety consequences that are the main concern of technical experts (NRC, 1996).

3.2.1 Research on Social Risk

There is a large body of research on social risk that focuses on the perceptions of and responses to nuclear power, nuclear weapons, and radioactive waste disposal. This research has shown that perceptions of risk

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

can have gender, racial, and cultural predispositions. A brief review of this research is provided below.

Studies have found that men tend to “rate a wide range of hazards as lower in risk than do women” including nuclear technologies (e.g., Finucane et al., 2000, p. 169). Flynn et al. (1994, p. 1101) found that white men have been found on average to perceive risks, including technologies such as nuclear power and waste “as much smaller and much more acceptable” than other people (also see Finucane et al., 2000). Vaughan (1995; see also Vaughan and Nordenstam, 1991) found that African Americans, when compared with others, tend to perceive risks as higher and support stricter regulatory actions for issues involving nuclear power plants or the disposal of radioactive waste. These predispositions may be related to the sociocultural contexts within which people live, including their beliefs about the trustworthiness of risk management institutions. Vaughn (1995, p. 175) notes:

Because prior beliefs about risk, perceptions about the trustworthiness of various government agencies and beliefs about risk management process evolve within sociocultural contexts, they likely are not independent of broader social experiences that bound and structure perspectives and worldviews…. Different patterns of belief and value systems relevant to risk management are likely to be observed across diverse ethnic and socioeconomic communities to the degree to which these communities’ social and cultural contexts have varied.

These sociocultural predispositions have been the topic of numerous studies (e.g., Dake, 1991, 1992; Jenkins-Smith and Smith, 1994; and Peters and Slovic, 1996).

There is also quantitative and qualitative evidence (e.g., United Church of Christ, 1987; GAO, 1983; Zimmerman, 1993; Goldman and Fitton, 1994) that not all people and communities bear the burden of environmental problems equally, including those arising from transportation of hazardous materials. This disproportionate burden has been associated particularly with minority and low-income communities (Bryant and Mohai, 1992). The imposition of preexisting risks on these communities may affect their conceptualization and framing of risk problems and make them even more vulnerable to risks from new activities (Sidebar 3.6).

A large body of published work has examined public perceptions concerning the proposed federal repository at Yucca Mountain, Nevada; much of the initial work was supported by the State of Nevada (e.g., Kasperson et al., 2001; see also, NRC, 1984; Slovic et al., 1991, 1994; Gregory et al., 1995). Consistent with the Nevada-sponsored studies, a National Research Council committee that examined the development of geologic repositories noted that the “[g]eneral public in almost every nation where data have

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

SIDEBAR 3.6
Publics, Affected Communities, and Vulnerable Communities Defined

There is a temptation to talk of “the public” or “the community” when thinking of risk estimates or tasks such as communication or the provision of information. However, the situation is far more complex than this. There are many publics (Jacobson, 1999) differentiated by both demographic (ethnicity, income) and interest-based criteria, and many groups or communities differentiated by numerous criteria of which demographics is just one.

In addition, for any project with potentially adverse consequences, such as those that might result from the transportation of spent nuclear fuel and high-level waste, there are affected groups and vulnerable groups. Affected groups are all communities within an influence zone of a transportation project. This is a hypothetical zone, which, for spent fuel and high-level waste transportation, would extend out some distance on either side of designated shipping routes. Within these affected communities will be vulnerable groups who, because of disproportionate exposures to other health-affecting substances, or because of ethnic, linguistic, or socioeconomic issues, may be less able to read or understand information from the authorities, to act in a first-responder role, to exit the area in a timely manner in an emergency, or to otherwise cope with an emergency. The 2005 Hurricane Katrina disaster in New Orleans is an unfortunate illustration of this point: many poor, mostly black, New Orleans residents had no means to evacuate the city and were stranded in their homes or in shelters of last resort. These vulnerable groups may have to be identified and given special consideration by the authorities, including—but not limited to—translated materials, emergency warnings in different languages, and appropriate first-responder training.

been collected perceives nuclear technologies and radioactive wastes as the riskiest of all hazards and expresses great concern about them” (NRC, 2003, p. 56).

There is a smaller body of research that specifically examines the potential social risks of transporting radioactive waste. This research has generally followed one of two approaches. The first and most common approach relies on survey interviews taken from systematic samples of people (adults) from the affected populations. The second approach, often referred to as “hedonic studies,” relies on direct measures of behaviors that reflect responses to the transportation of nuclear waste.

Survey research has the immediate advantage of obtaining individuals’ responses to specific questions about their own risk perceptions, beliefs, preferences, and anticipated behaviors. Of course, anticipated behaviors do not always match real behaviors. Surveys can be targeted to respondents of particular relevance to the transportation program. Quite a num-

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

ber of surveys have focused on nuclear waste transport, many of which are accessible on the Nevada Nuclear Waste Project Office Web site (http://www.state.nv.us/nucwaste/). Some of the most directly relevant survey research is summarized in the following paragraphs.

The University of New Mexico (UNMIPP, 2004) reported on a decade-long series of surveys on public perceptions of the risks associated with the Waste Isolation Pilot Plant among New Mexico residents. One survey item asked respondents to indicate whether they believed the facility was safe to open or was slightly, somewhat, or very risky. Over time, support gradually increased, and it appeared to increase significantly once the first shipments of transuranic waste reached the facility without incident.

A DOE-sponsored telephone-based survey of South Carolina residents living near the Savannah River Site examined residents risk perceptions of radioactive waste cleanup and disposal activities at the site, including the transport of radioactive waste (not explicitly including spent fuel) to and from the site. The study authors (Williams et al., 1999, p. 1028) noted that respondents were also more than four times more likely to believe that transport of waste from the site posed a fair to certain chance of harm than a small or no chance of harm. Truck was seen as being the most risky mode of transport. The study found that heightened risk perceptions among these residents were based upon their expectation of economic loss, their financial security, proximity to the site, and their trust in Savannah River Site officials (Williams et al., 1999, p. 1033).

The State of Nevada is located at the end of the transportation funnel for shipments to the planned Yucca Mountain repository. Consequently, larger numbers of spent fuel and high-level waste shipments will pass through communities in that state than anywhere else in the country if a federal repository at Yucca Mountain is opened. Two surveys—one of residents, the other of bankers and appraisers—were undertaken by the Urban Environmental Institute, LLC (UER) in 2000 to assess potential transportation-related impacts in Clark County, Nevada, which includes the city of Las Vegas. More than 70 percent of the respondents to UER’s residential survey indicated that they would not consider purchasing residential property near a highway designated for spent fuel transport. The UER survey of appraisers and bankers indicates that under routine transport conditions, residences 1 mile from transportation routes may see property value decreases of 2.0 to 3.5 percent, while commercial-office properties and industrial properties might decline in value from 0.5 to 3.0 percent. The study found that significant and adverse impacts on property values are likely to extend up to at least 3 miles from planned transportation routes (UER, 2000, p. 71).

UER also has studied the potential impacts of spent fuel transport near Moapa tribal lands in Nevada (UER, 2001). These lands are located near

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

Interstate 15, a route identified for possible truck shipments to Yucca Mountain. Tribal lands are located within 5 miles of I-15, and the major revenue source for the tribe is a gaming center located near the interstate. The UER concluded that an accident near Moapa lands would put the “tribe in an extremely vulnerable position in terms of economic well-being since that enterprise generates 90 percent of the tribe’s revenues” (UER, 2001, p. 40). The tribe has plans for future economic developments along I-15, including a truck stop and sales of agricultural produce. The study concluded that an accident involving a spent fuel shipment near the Moapa exit along I-15 may cause declining property values and lost revenues, resulting in potentially severe adverse economic impacts on the tribe.

The UER has also conducted a survey to identify the potential impacts of spent fuel transportation on the Las Vegas and Moapa Paiutes (UER, 2002; see also, Nevada, 2002). Survey respondents noted that they were concerned not only with economic impacts, but also with what they termed the “moral” issue of transporting nuclear waste through Indian communities that have already experienced exposure to radioactivity from atomic bomb tests at the Nevada Test Site.

Intertech Services Corporation completed a study for Lincoln County, Nevada, on the potential adverse impacts to Caliente, Nevada, from a Yucca Mountain transportation program (Intertech Services Corporation, 2001). Caliente is the planned site for a rail spur junction to Yucca Mountain. The development of this junction is supported by city and county leaders. The study concluded that the transportation program would have “negative impacts on community cohesion, population driven effects, emergency management, highway accident risk, radiation exposure risk, and impacts from stigma that may reduce the desirability of Lincoln County as a place to live and as a destination for tourists” (Intertech Services Corporation, 2001, ES-2). The report notes (p. 51) that although “scientific estimates of risk for an accident resulting in a release of radiation into the environment may be quite low, the risk is not zero.” The report also notes (p. 51–52), “To the degree that media amplifies the incident, even when there is no radiation release, the economic and fiscal consequences can be expected to be much greater than from a similar accident without nuclear waste.”

Transportation-related surveys taken in other parts of the country are broadly consistent with these results. A national survey of 972 people, which was part of the University of Maryland 1997 Omnibus Survey (Flynn et al., 1998), examined the perceived risks and property value losses resulting from the transportation of spent fuel. The survey found that nearly two-thirds of the respondents thought the value of properties located along spent fuel transportation routes would be lowered. Seventy percent of respondents thought that terrorist groups could successfully attack spent fuel

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

shipments. Most respondents stated an unwillingness to live near a spent fuel transportation route, and a majority of the respondents reported that they considered the transport of spent fuel to be more risky than the transport of industrial chemicals or gasoline.

There are fewer hedonic studies of people’s reactions to nuclear waste transport, in part because these studies are more expensive and more difficult to carry out. Only one study, which is described below, was available for review by the committee.

A DOE-sponsored study of real estate transactions in South Carolina (Gawande and Jenkins-Smith, 2001) measured the effects of a series of highly publicized shipments of foreign spent fuel to the Savannah River Site (research reactor spent fuel shipments to the Savannah River Site are described in more detail in Chapter 4). The authors found no correlation between the spent fuel shipments and property values in rural Aiken County, where there is a long experience with nuclear materials management. In urban and populous Charleston County, however, “the net gain in value associated with being 5 miles away from the route relative to a property on the route was nearly 3 percent of the average home value” (Gawande and Jenkins-Smith, 2001, p. 229) once the shipments were under way. The authors caution about making generalizations concerning the effects of hazardous material shipments based on this survey, however, because of data limitations.

During the scoping process for the draft EIS for Yucca Mountain, DOE received many public comments about the need to address risk perceptions and the potential stigmatization of Nevada, in particular the Las Vegas area, due to the transportation and disposal of spent fuel and high-level waste. In response, DOE sponsored a review of relevant perception-based impacts and stigma effects literature, in which qualitative assessments were made of the likelihood of these impacts. The literature reviewed included studies sponsored by DOE, Nevada, and others. The report resulting from this review concluded (O’Connor, 2001, p. 2):

… absent accidents, there is no reason to expect impacts to property owners in areas beyond the transportation corridors. Even absent accidents, however, two studies report that, at least temporarily, a decline in residential property values of approximately 3 percent may be expected in transportation corridors in urban areas…. More research on whether property values have fluctuated with the transportation of radioactive materials would be beneficial, although the research would not allow analysts to know with certainty whether there would be any impacts from perceptions of shipments of spent nuclear fuel and high-level waste to a Yucca Mountain Repository, or how long such impacts would persist.

The final EIS for Yucca Mountain reached a similar conclusion (DOE, 2002a, p. N21):

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

There is a consensus among social scientists that a quantitative assessment of the potential impacts from risk perceptions of the proposed repository and the transportation of spent nuclear fuel and high-level radioactive waste is impossible at this time and probably unlikely even after extensive additional research. The implication is not that impacts would probably be large, but simply difficult to quantify.

In summary, scientific research has generally shown the following:

  • The public generally perceives nuclear-related activities to carry a higher risk than non-nuclear activities.

  • These risks are not perceived in isolation, but in a broader context of social experiences and risk management processes—for example, in the context of proposals for increasing reliance on nuclear energy that would also require transportation of additional spent fuel.

  • Social processes have the potential to amplify or attenuate social risks arising from the transport of spent fuel and high-level waste.

  • Risk perceptions may have gender, cultural, and ethnic predispositions.

  • Social risks are difficult to quantify and there are no universally agreed-upon metrics for comparing them.

  • Trust and confidence can play important roles in modulating these risks.

The last point about trust and confidence suggests that risk perceptions can be modulated (i.e., amplified or dampened) by the actions of organizations involved in implementing or opposing a transportation program. On the one hand, the publics’ trust of groups that seek to mobilize opposition to a transportation program may increase the perceived risks of transportation. On the other hand, public trust and confidence in government agencies that manage and regulate transport (e.g., DOE, USNRC, and their contractors) may amplify or dampen these effects. In other words, trust and confidence serves to amplify or dampen the publics’ response to signals sent by those who make claims and counterclaims about the risks of transportation (Freudenberg, 2003; Frewer, 2003).

Responses to programs for transporting spent fuel and high-level waste among members of the public will depend to a great extent on perceptions about the need for such transport as well as the risks involved. Those responsible for implementing transport programs can take several steps to inform public understanding of needs, options, risks, and benefits. They can also benefit from a better understanding of the reasons for public responses, whether in the form of support or opposition to a proposed program. Improved understandings of these issues by the public and transportation implementers can support better planning and operational deci-

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

sions, improve confidence in transportation management, improve safety, and potentially reduce conflict.

3.3 COMPARATIVE RISK

The statement of task for this study (Sidebar 1.1) directs the committee to provide a comparison between the principal risks for transporting spent fuel and high-level waste and other risks that confront members of society. In this section, the committee provides a comparison of the health and safety risks of spent fuel and high-level waste transportation with other types of risks to address this charge.

The committee made no attempt to compare social risks because of the difficulties in quantifying such risks. The committee has followed the common approach for risk comparisons by comparing risks on dimensions for which the most information currently exists. The committee is well aware that these dimensions may not represent the outcomes that are most important to some people. However, data are lacking to make meaningful quantitative or qualitative social risk comparisons, and there are no agreed-upon metrics for making such comparisons.

The committee’s objective in presenting this comparison is to inform readers’ understanding about the risks of spent fuel and high-level waste transportation, not to persuade readers that such risks are—or are not—acceptable. The committee recognizes that acceptability is a normative judgment; that is, there is no basis in science for judging the acceptability of transportation risks. Societal acceptability of risk is ultimately a public policy decision and may vary over time and among different societies. Individual acceptability is based on personal judgments.

There is a rich literature on risk comparisons that informed the committee’s work (Sidebar 3.7). An important finding from research on risk communication is that different audiences frequently find different information and comparisons more (or less) informative and relevant; some may be critical of a particular comparison, while others will find it helpful for understanding particular risks. At best, comparisons can help to improve people’s understandings about the risks of a given activity, which may or may not change their views about its acceptability. At worst, such comparisons can be seen as trying to manipulate public opinion or to “sell” a particular technology or approach. People can reasonably disagree about the “best” comparisons to use because each comparison will privilege some aspects of the risk context at the expense of others (Vaughan and Seifert, 1992; NRC, 1996). In short, there is no single “right” comparison that will satisfy and be understood by all audiences or that will convey all of the relevant information associated with a complex risk.

The committee was guided by two principles in developing compari-

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

SIDEBAR 3.7
Comparative Risks

A growing body of research has been used to inform the practice of risk comparisons (e.g., NRC, 1989, 1996; Roth et al., 1990; MacGregor et al., 2002a, 2002b; Johnson, 2003, 2004; Johnson and Chess, 2003). Key insights from this research include the following:

  • Comparisons can have subtle effects on judgments about relative risks and their significance.

  • Comparisons on multiple dimensions can be more helpful than comparisons on a single dimension.

  • Comparisons of different risks on a single dimension can be problematic when the risks are viewed as qualitatively different (e.g., voluntary vs. involuntary, familiar vs. unfamiliar).

  • Use of point estimates can be misleading when uncertainties are large.

  • Risk denominators (e.g., periods of exposure, population base) to the risk should be defined.

  • Risks should be meaningful to those presented with the comparisons.

Choices about which risk comparisons to make involve personal judgments about which risk outcomes are important (Crouch and Wilson, 1982; Vaughan and Seifert, 1992; NRC, 1996): for example, human fatalities, human morbidity, ecological impacts, economic costs, procedural fairness, distributional equity, intergenerational effects, personal rights, effects on institutional trust and risk management regimes. It may also be important to consider benefits alongside such outcomes to fully inform understandings and decisions. Choices about which outcomes to use in the comparison are not only technical or scientific; rather, they also reflect values—implicitly or explicitly—about the characteristics of the risks that are important to people. They are embedded in and reflect social values.

There are a potentially large number of competing outcomes and measures that may be relevant in a risk comparison. Meaningful comparison of risks need not consider all possible outcomes or measures. Instead, decisions must be made about what will be most useful and relevant. A previous National Research Council committee offers some cautionary advice in this regard (NRC, 1989, p. 172).

Risk comparisons can be helpful, but they should be presented with caution. Risk comparisons must be seen as one of several inputs to risk decisions, not as determinants of decisions. There are proven pitfalls when risks of diverse character are compared, especially when the intent of the comparison can be seen as that of minimizing a risk (by equating it to a seemingly trivial risk). More useful are comparisons of risks that help convey the magnitude of a particular risk estimate, that occur in the same decision context (e.g., risks from flying and driving to a given destination), and that have a similar outcome. Multiple comparisons may avoid some of the worst pitfalls.

There is a frequent tendency to compare risks on dimensions that can be quantified (e.g., estimates of fatalities). These dimensions do not always represent the outcomes that may be most important to people, but they may be the outcomes for which most information exists. Other outcomes—for example, those for the social risks described in Section 3.2—may be equally important, but data may be lacking to make meaningful comparisons.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

sons of health and safety risks. First, the committee considered it important to compare risks associated with like physical causes. Radiation is the primary hazard of concern in spent fuel and high-level waste transportation. Thus, the committee’s comparisons focus on risks associated with radiological exposures.

Second, the committee considered it important to compare risks associated with similar outcomes. Human exposure to radiation can lead to undesirable health outcomes. The primary health effect of concern from exposure to ionizing radiation is cancer.40 Exposure to low and moderate levels of radiation can lead to the induction of cancer, usually years to decades after the exposures occur; some of these induced cancers will be fatal. Exposure to high levels of radiation can result in radiation sickness and death in a much shorter period of time. Thus, the committee separates comparisons of doses associated with routine radiological transport risks, which have the potential to provide chronic exposures, and severe accident risks, which have the potential to provide acute exposures.

Risk estimates for cancer incidence and mortality from exposure to radiation and radionuclides are available (e.g., EPA, 1999; NRC, 2005a). Some individuals may find cancer incidence to be a more meaningful factor for risk comparisons given the dread that is often associated with this disease. Nobody welcomes a cancer diagnosis, even if the cancer is treatable. Cancer incidence is also used as the basis for U.S. compensation programs for workers, veterans, and members of the public exposed to radiation from national defense activities (NRC, 2005b). Moreover, the incidence of health effects (including cancer) is commonly used in risk assessments for chronic exposures to hazardous chemicals.

The numerical relationship between cancer incidence and cancer mortality varies with cancer site within the human body.41 Average lifetime lung cancer mortality in males, for example, is about 100 percent of cancer incidence. On the other hand, average lifetime prostate cancer mortality in males is about 22 percent, and average lifetime breast cancer mortality in females is about 25 percent. The average lifetime mortality for all solid cancers42 in the U.S. population is about 48 percent of cancer incidence. For leukemia, the average lifetime mortality rate is closer to 85–90 percent.

40  

Radiation exposure may have other health effects besides cancer. For example, recent research suggests that such exposures can contribute to the development of cardiovascular disease.

41  

Average lifetime risk estimates for non-radiation-induced cancer incidence and mortality for several cancer sites are available for the U.S. population. See NRC (2005a, Table 12-4) for example.

42  

Solid cancers (cancers manifested by the formation of tumors) constitute more than 98 percent of all human cancers in the U.S. population. Leukemia (cancer of the blood or blood-forming organs) constitutes the remaining cancers.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

Cancer incidence is most readily used for comparing chronic radiation exposures during routine transport to chronic radiation exposures from other activities. Alternatively, one can compare the magnitudes of the chronic exposures for different activities directly. People who are concerned about exposures to any anthropomorphic radiation, regardless of its health effects, may find this sort of comparison useful. For those interested in how these exposures relate to cancer incidence and mortality, the appropriate multiplicative conversion factors (see Sidebar 3.3) can be applied. The committee uses exposures in its comparisons for routine transport but also provides examples of how these exposures relate to cancer incidence and mortality.

The committee uses mortality in its comparative assessments for transportation accidents. This allowed the committee to compare cancer mortality from exposures to ionizing radiation in a spent fuel transportation accident with other types of hazardous material accidents—for example, deaths from an accident involving releases of chlorine from a rail tanker car.

The committee has used a wide range of comparison factors, some of which are more directly comparable than others. As noted previously, different individuals will find different measures to have more or less meaning. The committee hopes that its presentation of a large range of factors will provide most individuals with comparisons that are helpful.

3.3.1 Risks for Normal Transport

As described elsewhere in this chapter, transportation packages do not completely shield the radiation emitted by the spent fuel or high-level waste contained within them. Consequently, individuals who travel, work, and live along the routes used for shipping spent fuel and high-level waste might receive small radiation doses when loaded packages are transported in their vicinity. The dose received by given individuals will vary as the inverse square of their distances from the packages43 and directly in proportion to their exposure times. Individuals closest to the packages will receive comparatively larger doses for a given exposure time. Doses will drop off quickly, however, as the distance between the individual and the package increases.

The doses received by any one individual may be very small, but a large number of individuals may receive radiation doses over the life of a transportation program. The collective dose to the population of people exposed

43  

That is, doubling the distance results in one-fourth of the exposure. The inverse square law assumes that the radiation emanates from a point source. A transportation package is not a point source, however, so the inverse square law is only a rough approximation at close distances to it.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

to radiation, which is obtained by summing the doses received by all individuals within the population, can be used to estimate radiological risks from normal transport (Sidebar 3.3). The outcome of principal concern for routine exposures is cancer incidence and cancer mortality.

Quantitative risk assessment models that describe the association between radiation dose and cancer incidence or cancer mortality have been deduced from epidemiological and biological studies. A linear no-threshold association between dose and cancer risk from exposure to ionizing radiation such as X-rays and gamma rays44 is consistent with current epidemiological and biophysical understanding (NRC, 2005a). That is, the risk of radiation-induced cancer rises linearly with dose with no threshold below which the risk falls to zero. The relationship between radiation dose and radiation-induced cancer can be expressed as a straight-line function that passes through zero risk at zero dose.45 The slope of the line, referred to as the nominal probability coefficient, is between about 4 × 10−2 and 5 × 10−2 fatal cancer per sievert (4 × 10−4 to 5 × 10−4 fatal cancer per rem; ICRP, 1991). These estimates have high uncertainties at the low doses typical of normal transport conditions (NRC, 2005a).

This risk model is a probabilistic function. It expresses the average number of fatal cancers that would be expected to occur in a population of individuals having a typical age and gender distribution for workers or the U.S. population for a given level of radiation exposure. Such risk models are used for setting standards for radiation exposure in the United States and many other countries. These models are also used for estimating risks to populations from specific activities involving the use of radiation. For example, such models were used to estimate latent cancer fatalities in the final Yucca Mountain EIS (DOE, 2002a; see Table 3.8) for the transport of spent fuel and high-level waste.

The routine radiological risks to a given population are scenario specific. That is, the risks depend on factors such as the number of packages transported; package inventories; shipping modes and routes; and population densities along shipping routes. The most complete estimate of scenario-specific routine radiological risks for spent fuel and high-level waste transportation is provided by the planned Yucca Mountain transportation program. Those estimates, which are provided in the final Yucca Mountain EIS and described in Section 3.1.2, were used by the committee for some of the comparisons in this section.

44  

This radiation is sometimes referred to as low energy transfer (LET) radiation.

45  

While the risk of developing a radiation-induced cancer is zero at zero dose according to the linear no-threshold model, the risk of developing cancer from other causes is much greater than zero. As noted elsewhere in this chapter, about 42 percent of the U.S. population will develop some form of cancer in their lifetimes due to causes other than radiation exposure.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

The final Yucca Mountain EIS (DOE, 2002a) provides estimates of routine radiological risks for both the mostly truck and mostly rail transport scenarios (see Section 3.1.2 and Table 3.8). While DOE has announced its preference for the mostly rail scenario, the committee provides estimates of radiological risks for both scenarios to help readers put these risks in perspective.

The estimated collective dose for the mostly rail scenario is 1200 to 1600 person-rem (Table 3.8), which applies to the public. Multiplying this dose by the nominal probability coefficient for fatal cancers produces an estimated average of about one latent cancer fatality among the 16.4 million people estimated to be exposed to radiation during the 24-year operational life of the transportation program. The estimated collective dose for the mostly truck scenario is 5000 person-rem, which would be expected to produce on average about three latent cancer fatalities out of the 10.4 million people that are estimated to be exposed to this radiation during the 24-year transport program. Of course, this comparison does not address some associated issues that people may care about, such as the voluntariness of the exposures.

To put these numbers in perspective, it is instructive to compare them to average cancer incidence and mortality in the U.S. population. Approximately 42 out of 100 people in the United States will be diagnosed with solid cancers during their lifetimes, and about 20 of those cancers will be fatal (NRC, 2005a, Table 12-4). Thus, of the 10.4 million to 16.4 million people who are estimated to be exposed to radiation (in almost all cases at very small levels) from transport of spent fuel and high-level waste to Yucca Mountain, approximately 4 million to 6 million would be expected to be diagnosed with solid cancers during their lifetimes for causes unrelated to the transportation program; about 2 million to 3.3 million of those cancers would be expected to be fatal. The estimated cancer fatalities from exposure to radiation during incident-free transport to Yucca Mountain—one for the mostly rail scenario and about three for the mostly truck scenario—would not be detectable in this much larger population of fatal cancers.

Other comparisons based directly on radiation dose46 are also possible. In Table 3.10 and Figure 3.3, the committee compares the estimated doses for maximally exposed workers and members of the public to radiation from the Yucca Mountain transportation program (DOE, 2002a, Chapter 6 and Appendix J), to three other types radiation exposures:

  1. Permissible maximum doses to workers and the public under current radiation standards and regulations

46  

Dose and risk are interchangeable in an arithmetic sense by multiplying or dividing by the nominal probability coefficient.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
  1. Doses received by members of the U.S. public from natural background radiation

  2. Doses received from selected medical diagnostic procedures that utilize radiation

Radiation standards and regulations establish ceilings for the maximum permissible radiation doses that workers and members of the public are allowed to receive from anthropogenic activities involving ionizing radiation. International standards are developed by international groups of radiation experts and health practitioners. These standards do not have the force of law but are frequently used as starting points by U.S. authorities (and authorities in other nations) for establishing national regulations.

U.S. regulations have been developed by the federal government through an elaborate administrative procedure47 that provides opportunities for public input. As such, these regulations represent a kind of social contract between the government and its citizens to protect worker and public health and safety. These standards set limits on what are often involuntary exposures to radiation, especially for members of the public. The exposures from spent fuel transport to a Yucca Mountain repository also will be largely involuntary for the individuals who receive them.

Natural background radiation consists of cosmic and solar radiation, external radiation exposure from radioactive materials present in rocks and soil, and radioactivity that is inhaled or ingested (see Sidebar 3.2). The committee presents four different estimates of natural background radiation in Table 3.10 (see also Figure 3.3): (1) the annual natural radiation background dose in Florida, the state with the lowest estimated annual natural background dose; (2) the annual natural radiation background dose in South Dakota, the state with the highest estimated annual natural background dose; (3) the average annual natural radiation background dose in the United States; and (4) the galactic cosmic background radiation dose received in a single round-trip airline flight between New York and Tokyo and also between St. Louis and Tampa.48

Natural background radiation is usually viewed as an involuntary and

47  

This procedure is specified by the Administrative Procedures Act: United States Code, Title 5, Part I, Chapter 5, SubChapter II.

48  

Airline travel subjects passengers to elevated doses of cosmic radiation originating from stars and galaxies. Radiation exposure increases with altitude and latitude and can also increase significantly during solar disturbances. The Federal Aviation Administration has developed a computer program (CARI-6) that calculates the effective dose of cosmic radiation received by individuals flying in aircraft on great circle routes between two airports. See http://www.faa.gov/education_research/research/med_humanfacs/aeromedical/radiobiology/cari6/index.cfm.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

TABLE 3.10 Radiation Dose Comparisons

Estimated Radiation Doses Received by Yucca Mountain Transportation Workers and the Public for Routine Transportation Operationsa

Maximum Radiation Doses Allowed by International Standards and U.S. Regulationsb

 

DOE annual occupational dose limit established in 10 CFR Part 835

Approximate annual dose to maximally exposed transport worker, mostly truck and mostly rail scenarios (DOE, 2002a, Tables 6-9, 6-12)

ICRP recommended annual occupational dose limit (ICRP, 1991, Table 6)

 

Current DOE annual occupational administrative dose limit (DOE, 1999)

 

All-pathways annual dose limit to reasonably maximally exposed individual near Yucca Mountain at time periods greater than 10,000 years after repository closure (70 FR 49014, August 22, 2005)

Approximate annual dose to maximally exposed service station worker, mostly truck scenario (DOE, 2002a, Table 6-9)

ICRP recommended annual public dose limit (ICRP, 1991, Table 6)

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

Examples of Natural and Anthropogenic Radiation Exposures

Radiation Dose Limits or Exposures, mSv (mrem)

Notes

 

50 (5000)

 

20 (2000)

ICRP standards are for doses averaged over defined periods of 5 years, not to exceed 50 mSv (5000 mrem) in any one year

20 (2000)

Maximally exposed transport worker is assumed to receive the maximum allowable DOE occupational administrative dose

Single whole-body CT scan (Brenner and Elliston, 2004)

12 (1200)

Weighted average dose to major organs

Approximate annual natural background radiation dose in South Dakota (Mauro and Briggs, 2005)

9.6 (960)

Includes doses from exposure to radon

 

3.5 (350)

EPA draft standard (40 CFR Part 197)

Average U.S. annual natural background radiation dose (NCRP, 1987)

3 (300)

Includes doses from exposure to radon

Approximate annual natural background radiation dose in Florida (Mauro and Briggs, 2005)

1.3 (130)

Includes doses from exposure to radon

 

1 (100)

Maximally exposed worker is assumed to receive the maximum allowable dose under ICRP guidelines and 10 CFR Part 20

 

 

ICRP guideline is for doses from all sources except natural, medical, and accidental exposures

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

Estimated Radiation Doses Received by Yucca Mountain Transportation Workers and the Public for Routine Transportation Operationsa

Maximum Radiation Doses Allowed by International Standards and U.S. Regulationsb

 

All-pathways annual dose limits for release of radiation to the environment from land disposal facilities (10 CFR Part 61)

 

All-pathways annual dose limit to reasonably maximally exposed individual near Yucca Mountain for first 10,000 years after repository closure

Approximate annual dose to maximally exposed resident near rail stop, mostly rail scenario (DOE, 2002a, Table 6-12)

 

 

Maximum hourly dose allowed at 2 meters (about 6.5 feet) from the lateral surfaces of a transport vehicle carrying spent fuel or high-level waste (49 CFR 173.441(b) and 10 CFR 71.47(b)(3))

Approximate annual dose to maximally exposed resident along rail route, mostly rail scenario (DOE, 2002a, Table 6-12)

 

NOTE: EPA = Environmental Protection Agency; ICRP = International Commission on Radiological Protection.

aAnnual doses were calculated by dividing the total estimated dose given in DOE (2002a) by the 24-year length of the transportation program.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

Examples of Natural and Anthropogenic Radiation Exposures

Radiation Dose Limits or Exposures, mSv (mrem)

Notes

X-ray of human hip joint (Ngutter et al., 2001)

0.60 (60)

 

 

0.25 (25)

 

 

0.15 (15)

EPA standard 40 CFR Part 197

Round-trip airline flight between New York and Tokyo (Friedberg and Copeland, 2003)

0.145 (14.5)

45-year average (1958–2002) dose calculated using the CARI-6 computer program, which estimates the effective dose of galactic cosmic radiation

 

0.12 (12)

Applies to maximally exposed residents who live near rail yards and crew change stops

Single chest X-ray (NRC, 2005a)

0.1 (10)

 

Single X-ray of a human extremity (Mettler et al., 2000)

0.01 (1)

 

Round-trip airline flight between St. Louis, Mo. and Tampa, Fla. (Friedberg and Copeland, 2003)

0.009 (0.9)

45-year average (1958–2002) dose calculated using CARI-6 computer program, which estimates the effective dose of galactic cosmic radiation

 

0.0007 (0.07)

 

bRadiation protection standards and regulations also include an ALARA (as low as reasonably achievable) requirement that usually results in doses to workers and the public that are well below the limits in this table. Moreover, constraints are sometimes placed on individual sources of radiation or practices involving the use of radiation to limit worker and public exposures.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

FIGURE 3.3 Graphical illustration of the radiation dose comparisons shown in Table 3.10. The dose data are plotted on a logarithmic scale to better illustrate the spread of values. Doses shown in the figure are annual limits (for standards and regulations) or exposures except for medical procedures and round-trip airline flights, which are one-time exposures. Black bars depict doses to workers or residents for the Yucca Mountain (YM) transportation program (SS = service station).

uncontrollable risk. In principle, people do have some control over the background dose they receive based on where they choose to live. In practice, however, the great majority of people probably do not explicitly include radiation dose considerations in decisions about where to live. Most people probably do not even know the average background radiation dose in their current location of residence.

Similarly, the radiation received by members of the public from a Yucca Mountain transportation program is also frequently viewed as involuntary and uncontrollable. Again, this is not completely true in principle; people have some control based on where they choose to live. In practice, however, it would be very difficult to make such a choice, given that transportation routes and schedules have not been established by DOE (see Chapter 5).

There is also a qualitative difference between natural background radiation and radiation from a Yucca Mountain transportation program. The former is natural, whereas the latter is the result of human activities. Although exposures to radiation from these two sources have identical bio-

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

logical effects on living organisms, the committee recognizes that some people may view the acceptability of these exposures differently given their different origins.

Under the linear no-threshold risk model, background doses would be expected to elevate the risk of a fatal cancer.49 The use of background radiation in risk comparisons has been criticized by some (e.g., MacGregor et al., 2002a,b) because it implicitly suggests that anthropogenic exposures of the same magnitude as background radiation are acceptable to society and it does not address the possible effects of cumulative exposures. The committee uses natural background radiation to give interested readers an established benchmark for making comparisons and makes no value judgments about the acceptability of doses at background levels.

Table 3.10 and Figure 3.3 also present the radiation doses received from a small number of common medical treatments. Comparisons using medical diagnostic procedures might be viewed by some people as inappropriate because the circumstances under which they are received are qualitatively different from spent fuel and high-level waste transportation: medical diagnostic procedures are voluntary and familiar and are widely perceived as having positive health benefits. The committee acknowledges these differences, but nevertheless decided to use medical procedures in its comparisons precisely because they would be familiar to many readers. The committee selected medical diagnostic procedures that represent relatively high, medium, and low radiation exposures to aid readers in making comparisons.

The entries in Table 3.10 and Figure 3.3 are arranged from high to low dose to provide a visual comparative ranking. This “risk ladder” is commonly used to display comparative information (Covello et al., 1989). Several noteworthy observations can be made. First, according to analyses presented in the final Yucca Mountain EIS (DOE, 2002a), maximally exposed workers (primarily transportation crews, escorts, and inspectors) for the Yucca Mountain transportation program (first column in Table 3.10) are assumed to receive annual doses at the limits of the current international standards and DOE administrative limits shown in the second column of the table. The final EIS (DOE, 2002a, p. 6-43) notes that “individual crew members who operated legal weight trucks and escorts for rail shipments could be exposed to as much as 48 rem over 24 years of operation (maximum exposure of 2 rem each year).” In practice, this probably means that DOE will monitor worker doses to ensure that they do not exceed these limits. These exposures will be about seven times higher than average annual natural background radiation doses and about twice as high as the dose received in a whole-body CT (computed tomography) scan.

49  

However, epidemiologic studies have not observed an association between background exposures and latent cancer incidence or fatalities.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

According to the final EIS, under the mostly truck scenario, the maximally exposed service station worker could receive a dose of about 1.3 mSv (130 mrem) per year, which would exceed current allowable dose limits to members of the public of 1.0 mSv (100 mrem) per year from all anthropogenic, nonmedical sources. The final Yucca Mountain EIS (DOE, 2002a, p. 6-40) notes that measures would be taken to keep this dose at or below the 1.0 mSv (100 mrem) limit. It should be noted that this worker dose estimate is very conservative: it assumes that every spent fuel and high-level waste truck shipment bound for Yucca Mountain stops at the service station during the 1800 hours the worker is on duty each year for 24 years.

Maximally exposed members of the public are estimated to receive substantially lower annual radiation doses from a Yucca Mountain transportation program as shown by the two bottom-most entries in the first column of the table. The maximally exposed resident near a rail stop (for the mostly rail scenario) would receive an annual dose of about 0.12 mSv (12 mrem). This is roughly equivalent to the dose from about one chest X-ray or one round-trip airline flight between New York and Tokyo. The maximally exposed resident near a rail route (again for the mostly rail scenario) would receive about 0.0007 mSv (0.07 mrem), which is about 6 percent of the dose received in an X-ray to a human extremity (e.g., hand or foot).

3.3.2 Transport Accident Risks

Given the robust construction of spent fuel transportation packages and the rigorous regulatory requirements for transporting them (Chapter 2), significant releases of radioactive material are very unlikely except possibly in extreme accidents, as indicated by the studies in Section 3.1.2. The final Yucca Mountain EIS estimates that the probability of such accidents is very low: 2.3 in 10 million per year for trucks to 2.8 in 10 million per year for trains (Table 3.8). This EIS also estimates exposures from releases in such accidents (Table 3.8): Estimated exposures in a maximally reasonably foreseeable accident would range from about 1100 person-rem for truck accidents to 9900 person-rem for train accidents. The maximally exposed individual is estimated to receive between 3 and 29 rem of radiation, which would be insufficient to cause acute radiation sickness or death. This exposure is estimated to produce between 0.5 and 5 latent cancer fatalities.

The committee provides a comparison of the potential consequences of extreme accidents involving spent fuel transportation packages with those for other types of hazardous materials transport using cumulative complementary distribution functions. The construction of these functions for accidents involving a loaded spent fuel package is described in Section 3.1.2.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

For this comparison, the committee used the mean CCDF for accidents involving rail transport of PWR spent fuel that was analyzed in the reexamination study (Sprung et al., 2000) and is shown in Figure 3.2. The committee compared this mean CCDF to those for accidents involving rail transport of three other kinds of hazardous materials: a flammable liquid (methanol), a flammable gas (propane), and a toxic gas (chlorine). These materials were selected because they behave differently under accident conditions and produce a wide range of consequences.

The CCDFs for these hazardous materials were estimated using a computer model that was designed to study the risks of hazardous materials shipments by rail.50 The model was a joint effort of the Chemical Manufacturers Association (now the American Chemistry Council), the Association of American Railroads, and the Railway Progress Institute. The model was designed to be used by the participating associations and their member companies to evaluate changes to rail hazardous material transportation equipment, routings, and operating practices and to evaluate the effectiveness of options for reducing the risk of accident-caused hazardous material releases from tank cars through such changes. The model has not been published in the open literature, but it was peer reviewed during its development.

The overall model has two main components:

  1. A frequency submodel that provides an estimate of the probability of occurrence and size of a release as a function of railroad operating factors (e.g., speed, track class) and tank car type

  2. A consequence submodel that provides estimates of the consequences of a release of a defined volume of a specific chemical for human and/or environmental impact51

The model also has an extensive database that contains accident rates, benefits of risk reduction options, release probabilities, ignition probabilities, spill size distributions, basic sets of weather conditions, chemical properties for eight preselected materials, and other information needed to run the model. The eight materials included in the model are acetaldehyde, ammonia, chlorine, ethylene oxide, methanol, propane, sodium hydroxide, and styrene.

50  

Inter-Industry Rail Safety Task Force’s Detailed Rail Model, Version 2.0, 1996.

51  

SuperChems™ is the consequence modeling package used within the model to generate the hazard zones for potential human impacts.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

The model is designed to run “projects.” A project is defined by

  • A hazardous material of interest,

  • A designated type of railcar,

  • A specified number of trips (trains) of interest, and

  • A route, which includes information on length, track class, train speed, train length, number of hazardous material cars of interest per train, population density (for human impact) and/or soil type (for environmental impact).

Each route is generally subdivided into pieces, called segments, within which the variables listed above are essentially constant.

This model was used to calculate CCDFs for a single railcar carrying 20,000 gallons of three types of hazardous materials (chlorine, propane, and methanol) being transported in a general train with typical train speeds, track conditions, and train lengths. The number of shipments (100), the route lengths (about 1600 miles), and the population densities along the shipping routes were approximately the same for these three types of hazardous material shipments and the spent fuel shipments. The results should not be taken as exact estimates, but they are useful for comparison purposes.

The results of the calculations are plotted in Figure 3.4. The horizontal axis represents the number of expected fatalities from an accident having an annual frequency shown on the vertical axis. The CCDF for spent fuel shown on the figure was plotted by multiplying the mean CCDF curve shown in Figure 3.2 by a nominal probability coefficient of 5.75 × 10−2 fatal cancer per sievert (5.75 × 10−4 fatal cancer per rem)52 (EPA, 1998b, Table 7.3).

Several features of this plot are noteworthy: First, the mean CCDF for chlorine has a relatively flat shape and has the highest accident frequencies and fatalities of the four cases examined. Chlorine gas is highly toxic and can be fatal if inhaled. Once released, gas can be dispersed widely by wind and can have adverse consequences even at relatively low concentrations. Thus, accidental releases can have adverse consequences even in lightly populated areas and can produce many casualties in densely populated areas.

Accidental releases of flammable gases such as propane can have similar consequences to toxic gas releases, but the expected number of fatalities is lower. The primary consequence of concern in a flammable gas release is an explosion or large fire. This requires an ignition source to be present when the proper fuel-air mixture is attained following the accident. The

52  

For low-dose, low linear energy transfer radiation, assuming uniform irradiation of the body. This nominal probability coefficient is age and gender averaged.

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

FIGURE 3.4 Complementary cumulative distribution functions showing expected fatalities from hypothesized accidents during transport of three types of hazardous materials and spent fuel. Calculations are explained in the text.

consequences of an explosion or fire will be more localized than a toxic gas release; hence, the expected fatalities from accidental releases are lower.

Accidental releases of flammable liquids such as methanol would be expected to have even fewer consequences. These consequences will generally be more localized to the area of the spill, and not all releases will yield fatalities. The mean CCDF is truncated at about three fatalities due to these localized effects.

The mean CCDF for accidental releases of radioactive material from spent fuel packages has the same general shape as the CCDF for propane. However, the frequency of accidents that lead to such releases is expected to be four to five orders of magnitude lower because of the robust construction of the transportation packages. Figure 3.4 shows that on a comparative basis, the likelihood of extreme accidents that would lead to fatalities is several orders of magnitude lower for spent fuel than for the other hazardous materials shown in the figure. In Section 3.1.2, the committee notes

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

that the risk estimates provided in the reexamination study (Sprung et al., 2000) from which this CCDF was taken are likely to be neither realistic nor bounding and may overestimate the risks. In other words, the risk estimates for accidents involving spent fuel shown in Figure 3.4 may be higher than is actually the case.

3.4 TRANSPORTATION RISKS: FINDINGS AND RECOMMENDATIONS

The committee concludes this chapter with findings and recommendations in response to the first three charges of its original statement of task shown in Sidebar 1.1:


FINDING: There are two potential sources of radiological exposures from transporting spent fuel and high-level waste: (1) radiation shine from spent fuel and high-level waste transport packages under normal transport conditions; and (2) potential increases in radiation shine and release of radioactive materials from transport packages under accident conditions that are severe enough to compromise fuel element and package integrity. The radiological risks associated with the transportation of spent fuel and high-level waste are well understood and are generally low, with the possible exception of risks from releases in extreme accidents involving very long duration, fully engulfing fires. While the likelihood of such extreme accidents appears to be very small, their occurrence cannot be ruled out based on historical accident data for other types of hazardous material shipments. However, the likelihood of occurrence and consequences can be reduced further through relatively simple operational controls and restrictions and route-specific analyses to identify and mitigate hazards that could lead to such accidents.


RECOMMENDATION: Transportation planners and managers should undertake detailed surveys of transportation routes to identify potential hazards that could lead to or exacerbate extreme accidents involving very long duration, fully engulfing fires. Planners and managers should also take steps to avoid or mitigate such hazards before the commencement of shipments or shipping campaigns. (See also the recommendation to transportation regulators in Chapter 2 on operational controls and restrictions on spent fuel and high-level waste shipments to reduce the chances that such hazards might be encountered in actual service.)


The finding that “radiological risks … are well understood and are generally low” is based on a large set of observational data and studies described in this chapter and in Chapter 2. These include the following:

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
  • Rigorous international standards and U.S. regulations for the design, construction, testing, and quality assurance of spent fuel packages, including the built-in safety margin requirements for package designs (see Chapter 2); and more than four decades of worldwide experience in transporting spent fuel (Section 3.1). Although there have been accidents and incidents, to the committee’s knowledge there has never been a large-scale release of radioactive materials reported from the failure of a spent fuel package during an accident. The broad sharing of information on experiences and best practices by transportation planners, implementers, and regulators through organizations such as the IAEA promotes the continued maintenance of this safety record.

  • Full-scale crash testing of transport packages under severe accident conditions (Section 2.3). These tests show that properly constructed spent fuel packages can withstand severe accidents without a loss of containment that would result in releases of radioactive material that exceed regulatory limits. These tests also illustrate that the regulatory requirements for spent fuel packages (e.g., free-drop tests) produce in many cases more severe tests of package integrity than do severe accidents.

  • A series of increasingly sophisticated analytical and computer modeling studies of spent fuel transport package performance (Section 3.1.2). The most recent of these studies (Sprung et al., 2000; DOE, 2002a) have attempted to estimate risks using actual spent fuel transport package, fuel, route, and severe accident characteristics and generally conservative assumptions and models.

  • Other studies that examine the mechanical and thermal loading conditions from severe accidents that did not involve spent fuel transport (Section 2.2.3). These studies have shown that with the possible exception of very long duration fires, the loading conditions from these accidents would not have exceeded regulatory limits.

Of course, spent fuel transportation is not risk-free, and past experience is not necessarily a useful predictor of future performance. The fact that spent fuel transportation risks have been low in the past does not necessarily mean that risks will also be low in the future. Future risks depend on a number of factors including the quantities and ages of spent fuel transported, associated scaling issues related to the overall size of the transport program, transport modes, and the care taken in fabricating and maintaining transport packages and executing transportation operations. Ongoing vigilance by regulators and shippers will be essential for maintaining low-risk programs in the future, especially for the scale-up and operation of large-quantity shipping programs. Any accident or terrorist attack that results in the large-scale release of radioactive material into the environment would likely have worldwide implications and could result in a

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

temporary or even permanent halt to ongoing transportation programs for spent fuel in the United States.

The recommendation calls for transportation implementers to survey the routes they plan to use for spent fuel and high-level waste to identify hazards that could lead to very long duration fires. This recommendation arises from the finding in Chapter 2 that very long duration, fully engulfing fires might produce thermal loading conditions sufficient to compromise package containment effectiveness. The recommended survey would involve traveling the route in advance of a shipment (or shipping campaign if several shipments are planned) to identify

  • Facilities close to the route that use or store large quantities of flammable materials (e.g., refineries, petroleum and gas storage tanks);

  • Large-volume flammable hazardous material shipments along the routes to be used; and

  • Other route conditions (e.g., the presence of multitrack tunnels, bridges, rail yards, and sidings, as well as remote locations) that could make it difficult to deploy an effective firefighting capability.

Once these conditions have been identified, implementers can take steps to avoid or mitigate these hazards. For example, routes can be altered to avoid multitrack train tunnels, and time spent in rail yards and sidings, where packages could be exposed to other trains carrying large amounts of flammable materials, can be minimized. Where such hazards cannot be avoided completely, shipments can be scheduled to minimize encounters with other hazardous materials trains, or emergency response preparedness can be improved along specific route segments of concern.

The committee judges that none of these recommended survey and mitigation actions would be difficult or expensive to implement. Transportation implementers and regulatory authorities now routinely survey routes to identify other safety and security concerns prior to shipping spent fuel. This recommended action simply represents an expansion of an activity that many implementers already carry out on a routine basis.


FINDING: The social risks for spent fuel and high-level waste transportation pose important challenges to the successful implementation of programs for transporting spent fuel and high-level waste in the United States. Such risks, which can result in lower property values along transportation routes, reductions in tourism, and increased anxiety, have received substantially less attention than health and safety risks, and some are difficult to characterize. Current research and practice suggest that transportation planners and managers can take early proactive steps to characterize, communicate, and manage the social risks that arise from their operations. Such

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

steps may have additional benefits: they may increase the openness and transparency of transportation planning and programs; build community capacity to mitigate these risks; and possibly increase trust and confidence in transportation programs.


RECOMMENDATION: Transportation implementers should take early and proactive steps to establish formal mechanisms for gathering high-quality and diverse advice about social risks and their management on an ongoing basis. The committee makes two recommendations for the establishment of such mechanisms for the Department of Energy’s program to transport spent fuel and high-level waste to a federal repository at Yucca Mountain: (1) expand the membership and scope of an existing advisory group (Transportation External Coordination [TEC] Working Group; see Chapter 5) to obtain outside advice on social risk, including impacts and management; and (2) establish a transportation risk advisory group that is explicitly designed to provide advice on characterizing, communicating, and mitigating the social, security, and health and safety risks that arise from the transportation of spent fuel and high-level waste to a federal repository or interim storage. This group should be comprised of risk experts and practitioners drawn from the relevant technical and social science disciplines and should be convened under the Federal Advisory Committee Act or a similar arrangement to enhance the openness of its operations. Its members should receive security clearances to facilitate access to appropriate transportation security information. The existing federal Nuclear Waste Technical Review Board, which will cease operations no later than one year after the Department of Energy begins disposal of spent fuel or high-level waste in a repository, could be broadened to serve this function.


This finding and recommendation spring from several factors: Social risk is a poorly understood phenomenon; expert opinion frequently differs; DOE does not, to the committee’s knowledge, have any precedent to guide its understanding and management of social risks; and most transportation program staff are not likely to be well acquainted with either theory or practice on this issue. Consequently, the committee concluded that broad input and advice on social risks will be essential to the establishment and ultimate success of programs to transport spent fuel and high-level waste to a federal repository or interim storage.

The recommendation represents pragmatic steps that transportation implementers can take immediately and at relatively low cost to better understand and (working with affected communities) manage the social risks from their programs. These groups are not intended to undertake research on risk. Instead, the committee intends that they have a practical, problem-solving focus and be committed to working closely with program

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×

staff to help it become more effective in carrying out the program’s mission. One of the most important functions of these advisory groups would be to foster continuous learning and improvement.

The recommendation to expand the scope and membership of the TEC Working Group builds on and complements existing public participation and communication activities within DOE’s transportation program for Yucca Mountain. The TEC Working Group is now comprised of state, tribal, local, and industry representatives, and it provides a conduit for communication and advice on topics such as emergency response, inspection and enforcement, training, and public information. The committee recommends that the membership of TEC be expanded to include social risk experts and representative stakeholders from affected communities to provide information on social risks of DOE’s transportation operations and their management.

The committee also recommends the establishment of a separate transportation risk advisory group that would advise DOE on characterizing, communicating, and mitigating the social, security, and health and safety risks to communities near transportation routes. The suggestion that the Nuclear Waste Technical Review Board could be broadened to serve this function is intended to take advantage of an established capability within the federal government. This group is independent of DOE and its membership is drawn from the scientific and technical communities. The procedures for nominating and appointing members to this board (i.e., presidential appointments based on nominations by the National Academy of Sciences) are designed to ensure that it is balanced and credible to carry out its mission.

Finally, although this recommendation is focused primarily on DOE, it also applies to any large-quantity shipping program, including the program to ship commercial spent fuel to centralized interim storage (e.g., Private Fuel Storage, LLC, in Utah).

Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 109
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 110
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 111
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 112
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 113
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 114
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 115
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 116
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 117
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 118
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 119
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 120
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 121
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 122
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 123
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 124
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 125
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 126
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 127
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 128
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 129
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 130
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 131
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 132
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 133
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 134
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 135
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 136
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 137
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 138
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 139
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 140
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 141
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 142
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 143
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 144
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 145
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 146
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 147
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 148
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 149
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 150
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 151
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 152
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 153
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 154
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 155
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 156
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 157
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 158
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 159
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 160
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 161
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 162
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 163
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 164
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 165
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 166
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 167
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 168
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 169
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 170
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 171
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 172
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 173
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 174
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 175
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 176
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 177
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 178
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 179
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 180
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 181
Suggested Citation:"3 Transportation Risk." Transportation Research Board and National Research Council. 2006. Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States. Washington, DC: The National Academies Press. doi: 10.17226/11538.
×
Page 182
Next: 4 Transport of Research Reactor Spent Fuel to Interim Storage »
Going the Distance?: The Safe Transport of Spent Nuclear Fuel and High-Level Radioactive Waste in the United States Get This Book
×
Buy Hardback | $53.00 Buy Ebook | $42.99
MyNAP members save 10% online.
Login or Register to save!
Download Free PDF

This book looks to provide an independent, objective, and authoritative analysis of the transportation of spent nuclear fuel and radioactive waste in the United States, while simultaneously examining risks and identifying current and future technical and societal concerns for such specialized transportation. Going the Distance? also gives comparisons between health and safety risks for transporting spent fuel and radioactive waste and other risks that confront members of society. Comparisons are provided for routine radiological transport, which has the potential to produce chronic radiation exposures and latent cancer, and severe accident risks, which have the potential to produce acute radiation sickness and death, as well as latent cancer. This book will inform readers about the risks of spent fuel and high-level waste transportation.

  1. ×

    Welcome to OpenBook!

    You're looking at OpenBook, NAP.edu's online reading room since 1999. Based on feedback from you, our users, we've made some improvements that make it easier than ever to read thousands of publications on our website.

    Do you want to take a quick tour of the OpenBook's features?

    No Thanks Take a Tour »
  2. ×

    Show this book's table of contents, where you can jump to any chapter by name.

    « Back Next »
  3. ×

    ...or use these buttons to go back to the previous chapter or skip to the next one.

    « Back Next »
  4. ×

    Jump up to the previous page or down to the next one. Also, you can type in a page number and press Enter to go directly to that page in the book.

    « Back Next »
  5. ×

    Switch between the Original Pages, where you can read the report as it appeared in print, and Text Pages for the web version, where you can highlight and search the text.

    « Back Next »
  6. ×

    To search the entire text of this book, type in your search term here and press Enter.

    « Back Next »
  7. ×

    Share a link to this book page on your preferred social network or via email.

    « Back Next »
  8. ×

    View our suggested citation for this chapter.

    « Back Next »
  9. ×

    Ready to take your reading offline? Click here to buy this book in print or download it as a free PDF, if available.

    « Back Next »
Stay Connected!