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1 Introduction T he U.S. Nuclear Regulatory Commission (USNRC) requested that the National Academy of Sciences (NAS) provide an assessment of cancer risks in populations near USNRC-licensed nuclear facilities. This assessment is being carried out in two consecutive phases. The focus of the Phase 1 scoping study, which is the subject of this report, is to identify scientifically sound approaches for carrying out an assessment of cancer risks. The results of this Phase 1 study will be used to inform the design of the assessment, which will be carried out in Phase 2. The complete study task is shown in Sidebar 1.1. The USNRC-licensed nuclear facilities referred to in the statement of task are nuclear power reactors and nuclear fuel-cycle facilities that utilize uranium for the production of electricity.1 These facilities are described in Sidebar 1.2. A large number of nuclear facilities have been constructed in the United States during the past six decades. Presently licensed USNRC facilities include: • 104 operating nuclear reactors (35 boiling water reactors and 69 pressurized water reactors) at 65 sites in 31 states (Table 1.1). • 13 fuel-cycle facilities in operation in 10 states. The operating facilities include four in situ uranium recovery facilities, one con- ventional uranium mill,2 one conversion facility, two uranium en- richment facilities, and five fuel fabrication facilities. There are 1 These are referred to as nuclear plants and fuel-cycle facilities in this report; the more ge- neric term nuclear facilities is used to refer to nuclear plants and fuel-cycle facilities collectively. 2 Currently on standby (i.e., available for operations but not currently operating). 11
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12 ANALYSIS OF CANCER RISKS SIDEBAR 1.1 Statement of Task The National Academies will provide an assessment of cancer risks in popula- tions living near U.S. Nuclear Regulatory Commission-licensed nuclear facilities. This assessment will be carried out in two consecutive phases: A Phase 1 scoping study will identify scientifically sound approaches for car- rying out the cancer epidemiology study that has been requested by the U.S. Nuclear Regulatory Commission. It will address the following tasks: 1. Methodological approaches for assessing off-site radiation dose, including consideration of: • athways, receptors, and source terms P • vailability, completeness, and quality of information on gaseous and liquid A radioactive releases and direct radiation exposure from nuclear facilities • pproaches for overcoming potential methodological limitations arising A from the variability in radioactive releases over time and other confounding factors • pproaches for characterizing and communicating uncertainties. A 2. Methodological approaches for assessing cancer epidemiology, including con- sideration of: • haracteristics of the study populations (e.g., socioeconomic factors, all age C groups, children only, and nuclear facility workers) • eographic areas to use in the study (e.g., county, zip codes, census tracts, G or annular rings around the facility at some nominal distances) • ancer types and health outcomes of morbidity and mortality C • vailability, completeness, and quality of cancer incidence and mortality A data • ifferent epidemiological study designs and statistical assessment methods D (e.g., ecologic or case-control study designs) • pproaches for overcoming potential methodological limitations arising from A low statistical power, random clustering, changes in population characteris- tics over time, and other confounding factors • pproaches for characterizing and communicating uncertainties. A The results of this Phase 1 scoping study will be used to inform the design of the cancer risk assessment, which will be carried out in Phase 2.
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13 INTRODUCTION additional state-licensed3 conventional uranium milling facilities and in situ leaching facilities that are not shown on Table 1.2.4 Figures 1.1a and 1.1b show the locations of currently operating nuclear plants and USNRC-licensed fuel-cycle facilities in the United States. Appli- cations for 24 additional nuclear reactors were under active review by the USNRC while the present study was in progress.5 1.1 BACKGROUND ON THE STUDY REQUEST In the late 1980s, the National Cancer Institute (NCI) initiated an investigation of cancer risks in populations near 52 commercial nuclear power plants and 10 Department of Energy nuclear facilities (including research and nuclear weapons production facilities and one reprocessing plant) in the United States (Jablon et al., 1990). The investigation compared cancer mortality rates in “study” counties (i.e., counties that contained nuclear facilities) with rates in “control” counties (i.e., counties that were similar to the study counties in terms of population size, income, education, and other socioeconomic factors but did not contain nuclear facilities). The NCI investigation also compared cancer registration (i.e., cancer incidence) rates in study and control counties in two states: Connecticut and Iowa. No differences in cancer mortality or incidence rates were observed between study and control counties. The authors of the study concluded that “if nuclear facilities posed a risk to neighboring populations, the risk was too small to be detected by a survey such as this one” (Jablon et al., 1991). The USNRC has been using the results of this NCI investigation as a primary resource for communicating with the public about cancer risks near the nuclear facilities that it regulates. However, this study is now over 20 years old. There have been substantial demographic shifts in populations around some of these facilities, and the facility inventory itself has changed; some facilities have shut down and new facilities have started up. Addition- ally, at least one facility that was not included in the NCI investigation (Nuclear Fuel Services in Tennessee) has become a focus of public interest. The NCI investigation had several limitations: The investigation uti- lized county-level mortality and, when available, incidence data. The use 3 Section 274 of the Atomic Energy Act of 1954 authorizes the USNRC to enter into agree- ments with state governors to discontinue the Commission’s regulatory authority for byprod- uct materials (radioisotopes), source materials (uranium and thorium), and certain quantities of special nuclear materials. States that have assumed regulatory authority for these materials are referred to as agreement states. 4 A listing of these facilities as of 2010 can be found at http://www.eia.gov/uranium/ production/annual/. 5 See http://www.nrc.gov/reactors/new-reactors/col/new-reactor-map.html.
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14 ANALYSIS OF CANCER RISKS SIDEBAR 1.2 Nuclear Fuel Cycle The nuclear fuel cycle comprises a set of industrial processes for producing elec- tricity from uranium. These processes are carried out in nuclear fuel-cycle facilities, as illustrated in Figure S.1. Facilities comprising the front end of the nuclear fuel cycle are involved in the extraction of uranium from the environment and its fabrication into fuel for nuclear reactors. The uranium fuel is utilized in nuclear power reactors to produce electricity. Modern reactors typically generate on the order of 3000 megawatts of ther- mal power and produce about 1000 megawatts of electrical power. Facilities comprising the back end of the nuclear fuel cycle are involved in managing this fuel after it has been utilized in reactors; fuel management activities can involve recycling, storage, and/or disposal. The only civilian back-end facilities currently in operation in the United States are interim storage facilities for managing used fuel, most of which are located at commercial nuclear power plants. In the United States, almost all of these fuel storage facilities are co-located with nuclear plants. The USNRC regulates five types of front-end fuel-cycle facilities: Mining facilities: Facilities that are used to extract uranium from the environment. Currently, uranium is extracted using either conventional mining or leaching methods. The former method involves the physical removal of uranium-bearing ores from the subsurface in underground and open-pit mines. The latter method includes in situ leaching, in which solutions are pumped into the subsurface to extract uranium, and heap leaching, in which solutions are sprayed onto piles of mined rock to extract ura- nium. This study is concerned only with in situ leaching facilities. (The USNRC did not ask the NAS to examine conventional mining facilities because these facilities are not regulated by that agency.) Milling facilities: Facilities that are used to process uranium ore or leach solutions to produce uranium oxide (U3O8) powder, or yellowcake. Mills can be standalone facilities, or they can be integrated into a uranium extraction operation. The former type of facil- ity is used for conventional mining operations, where a single mill can service several mines, whereas the latter type of facility is used for in situ leaching operations. Conversion facilities: Facilities that are used to convert yellowcake into a solid hexafluoride form (uranium hexafluoride, UF6). This compound sublimes to form a gas at about 56°C at standard atmospheric pressures. The gaseous form of this material is used in subsequent processing steps. Enrichment facilities: Facilities that are used to increase the concentration of of countywide data made it difficult to discern local effects around nuclear facilities, especially in geographically extensive counties. The investigation also focused primarily on cancer mortality, because good-quality cancer in- cidence data were largely unavailable at the time the study was conducted. (Incidence may be a better indicator of risk than mortality because advances in cancer treatments have lowered mortality rates for many types of cancer, including leukemia.)
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15 INTRODUCTION uranium-235 in uranium hexafluoride. Almost all natural uranium contains about 99.3 percent uranium-238 and about 0.7 percent uranium-235 by mass. Enrichment in- creases the mass percentage of uranium-235, the fissile (i.e., the component of the nuclear fuel that can be induced to fission with thermal [low-energy] neutrons) compo- nent of nuclear fuel, to between about 4 and 5 percent. In the United States, uranium enrichment is currently being carried out in gaseous diffusion and centrifuge plants. New plants that use laser enrichment technologies are under construction. Fuel fabrication facilities: Facilities that are used to convert enriched uranium hexa- fluoride into a uranium dioxide (UO2) solid and fabricate it into nuclear fuel for civilian reactors. Some of the fuel facilities being considered in this study have had or currently have dual civilian and defense missions. Prior to the USNRC assuming regulatory control, some of these facilities were previously regulated by the U.S. Department of Energy and its predecessor agencies. FIGURE S.1 Schematic depiction of the nuclear fuel cycle. SOURCE: USNRC. Figure S.1.eps bitmap The NCI investigation also did not attempt to estimate radiation expo- sures resulting from the operation of nuclear facilities. However, NCI inves- tigators noted that such exposures are likely to be “too small to result in detectable harm” (Jablon et al., 1991, p. 1407). Absent reliable information about radiation exposures, it is difficult to provide scientifically supportable explanations for any observed associations between a nuclear facility and cancer incidence or mortality.
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16 ANALYSIS OF CANCER RISKS TABLE 1.1 Civilian Nuclear Power Plants in the United States Number of Active Name of Nuclear Power Operating Reactors Plant (USNRC-abbreviated Reactor License Shutdown State in State plant names) Unit Issue Date Date Alabama 5 Browns Ferry Nuclear Plant 1 1973 (Browns Ferry) 2 1974 3 1976 Joseph M. Farley Nuclear 1 1977 Plant (Farley) 2 1981 Arizona 3 Palo Verde Nuclear 1 1985 Generating Station (Palo 2 1986 Verde) 3 1987 Arkansas 2 Arkansas Nuclear One 1 1974 (Arkansas Nuclear) 2 1978 California 4 Diablo Canyon Power Plant 1 1984 (Diablo Canyon) 2 1985 San Onofre Nuclear 1 1967 1992 Generating Station (San 2 1982 Onofre) 3 1982 Humboldt Bay Nuclear 3 1963 1976 Power Plant (Humboldt Bay) Rancho Seco Nuclear 1974 1989 Generating Station (Rancho Seco) Colorado 1 Fort Saint Vrain Generating 1973 1989 Station (Fort Saint Vrain) Connecticut 2 Millstone Power Station 1 1970 1998 (Millstone) 2 1975 3 1986 Haddam Neck (Connecticut 1968 1996 Yankee) Florida 5 Crystal River Nuclear 3 1976 Generating Plant (Crystal River) St. Lucie Plant (St. Lucie) 1 1976 2 1986 Turkey Point Nuclear Plant 3 1972 (Turkey Point) 4 1973 Georgia 4 Edwin I. Hatch Nuclear Plant 1 1974 (Edwin I. Hatch) 2 1978 Vogtle Electric Generating 1 1987 Plant (Vogtle) 2 1989
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17 INTRODUCTION TABLE 1.1 Continued Number of Active Name of Nuclear Power Operating Reactors Plant (USNRC-abbreviated Reactor License Shutdown State in State plant names) Unit Issue Date Date Illinois 11 Braidwood Station 1 1987 (Braidwood) 2 1988 Byron Station (Byron) 1 1985 2 1987 Clinton Power Station 1 1987 (Clinton) Dresden Nuclear Power 1 1959 1978 Station (Dresden) 2 1969 3 1971 LaSalle County Station 1 1982 (LaSalle) 2 1983 Quad Cities Nuclear Power 1 1972 Station (Quad Cities) 2 1972 Zion Nuclear Power Station 1 1973 1997 (Zion) 2 1973 1996 Iowa 1 Duane Arnold Energy Center 1974 (Duane Arnold) Kansas 1 Wolf Creek Generating 1 1985 Station (Wolf Creek) Louisiana 2 River Bend Station (River 1 1985 Bend) Waterford Steam Electric 3 1985 Station (Waterford) Maine 0 Maine Yankee Nuclear 1972 1996 Power Plant (Maine Yankee) Maryland 2 Calvert Cliffs Nuclear Power 1 1974 Plant (Calvert Cliffs) 2 1976 Massachusetts 1 Pilgrim Nuclear Power 1972 Station (Pilgrim) Yankee Rowe Nuclear Power 1961 1991 Station (Yankee-Rowe) continued
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18 ANALYSIS OF CANCER RISKS TABLE 1.1 Continued Number of Active Name of Nuclear Power Operating Reactors Plant (USNRC-abbreviated Reactor License Shutdown State in State plant names) Unit Issue Date Date Michigan 4 Donald C. Cook Nuclear 1 1974 Plant (Cook) 2 1977 Palisades Nuclear Plant 1971 (Palisades) Fermi 1 1966 1992 2 1985 Big Rock Point Nuclear Plant 1962 1997 (Big Rock Point) Minnesota 3 Monticello Nuclear 1 1970 Generating Plant (Monticello) Prairie Island Nuclear 1 1974 Generating Plant (Prairie 2 1974 Island) Mississippi 1 Grand Gulf Nuclear Station 1 1984 (Grand Gulf) Missouri 1 Callaway Plant (Callaway) 1 1984 Nebraska 2 Cooper Nuclear Station 1974 (Cooper) Fort Calhoun Station (Fort 1 1973 Calhoun) New 1 Seabrook Station (Seabrook) 1 1990 Hampshire New Jersey 4 Hope Creek Generating 1 1986 Station (Hope Creek) Oyster Creek Nuclear 1969 Generating Station (Oyster Creek) Salem Nuclear Generating 1 1976 Station (Salem) 2 1981
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19 INTRODUCTION TABLE 1.1 Continued Number of Active Name of Nuclear Power Operating Reactors Plant (USNRC-abbreviated Reactor License Shutdown State in State plant names) Unit Issue Date Date New York 6 James A. FitzPatrick Nuclear 1974 Power Plant (FitzPatrick) R. E. Ginna Nuclear Power 1969 Plant (Ginna) Indian Point Nuclear 1 1962 1974 Generating (Indian Point) 2 1973 3 1975 Nine Mile Point Nuclear 1 1969 Station (Nine Mile Point) 2 1987 Shoreham Nuclear Power 1989 1992 Station (Shoreham) North 5 Brunswick Steam Electric 1 1976 Carolina Plant (Brunswick) 2 1974 McGuire Nuclear Station 1 1981 (McGuire) 2 1983 Shearon Harris Nuclear 1 1986 Power Plant (Harris) Ohio 2 Davis-Besse Nuclear Power 1 1977 Station (Davis-Besse) Perry Nuclear Power Plant 1 1986 (Perry) Oregon 0 Trojan Nuclear Power Plant 1 1976 1992 (Trojan) Pennsylvania 9 Beaver Valley Power Station 1 1976 (Beaver Valley) 2 1987 Limerick Generating Station 1 1985 (Limerick) 2 1989 Peach Bottom Atomic Power 1 1967 1974 Station (Peach Bottom) 2 1973 3 1974 Susquehanna Steam Electric 1 1982 Station (Susquehanna) 2 1984 Three Mile Island Nuclear 1 1974 Station (Three Mile Island) 2 1978 1979 Shippingport Atomic Power 1957 1982 Station Saxton 1962 1972 continued
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20 ANALYSIS OF CANCER RISKS TABLE 1.1 Continued Number of Active Name of Nuclear Power Operating Reactors Plant (USNRC-abbreviated Reactor License Shutdown State in State plant names) Unit Issue Date Date South 7 Carolinas-Virginia Tube 1963 1967 Carolina Reactor Oconee Nuclear Station 1 1973 (Oconee) 2 1973 3 1974 H.B. Robinson Steam Electric 2 1970 Plant (Robinson) Virgil C. Summer Nuclear 1 1982 Station (Summer) Catawba Nuclear Station 1 1985 (Catawba) 2 1986 South Dakota 0 Pathfinder Atomic Plant 1964 1967 (Pathfinder) Tennessee 3 Sequoyah Nuclear Plant 1 1980 (Sequoyah) 2 1981 Watts Bar Nuclear Plant 1 1996 (Watts Bar) Texas 4 Comanche Peak Nuclear 1 1990 Power Plant (Comanche 2 1993 Peak) South Texas Project 1 1988 2 1989 Vermont 1 Vermont Yankee Nuclear 1972 Power Station (Vermont Yankee) Virginia 4 North Anna Power Station 1 1978 (North Anna) 2 1980 Surry Power Station (Surry) 1 1972 2 1973 Washington 1 Columbia Generating Station 1984 (Columbia) Wisconsin 3 Kewaunee Power Station 1973 (Kewaunee) Point Beach Nuclear Plant 1 1970 (Point Beach) 2 1973 La Crosse Nuclear 1969 1987 Generating Station (La Crosse)
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21 INTRODUCTION TABLE 1.2 USNRC-Licensed Facilities that Are Part of the Nuclear Fuel Cycle Site Name, Location Licensee Operational Status In situ Recovery Facilitiesa Crow Butte, NE Crow Butte Resources, Inc. Active Crownpoint, NM Hydro Resources, Inc. Not yet constructed Moore Ranch, WY Uranium One Active Smith Ranch and Highlands, Power Resources, Inc. Active WY Willow Creek, WY Uranium One Active Facilitiesa Conventional Uranium Mill Recovery Ambrosia Lake, NM Rio Algom Mining, LLC Decommissioning Church Rock, NM United Nuclear Corp. Decommissioning Homestake, NM Homestake Mining Co. Decommissioning Bear Creek, WY Bear Creek Uranium Co. Decommissioning Gas Hills, WY American Nuclear Corp. Decommissioning Gas Hills, WY Umetco Minerals Corp. Decommissioning Highlands, WY Exxon Mobil Corp. Decommissioning Lucky Mc, WY Pathfinder Mines Corp. Decommissioning Shirley Basin, WY Pathfinder Mines Corp. Decommissioning Split Rock, WY Western Nuclear, Inc. Decommissioning Sweetwater, WY Kennecott Uranium Corp. Stand-by Uranium Hexafluoride Conversion Facility Metropolis, IL Honeywell International, Inc. Active Uranium Fuel Fabrication Facilities Wilmington, NC Global Nuclear Fuels-Americas, Active LLC Columbia, SC Westinghouse Electric Company, Active LLC Columbia Fuel Fabrication Fac. Erwin, TN Nuclear Fuel Services, Inc. Active Lynchburg, VA AREVA NP, Inc. Mt. Athos Inactive Road Lynchburg, VA B&W Nuclear Operations Active Group Richland, WA AREVA NP , Inc. Active Mixed Oxide Fuel Fabrication Facility Aiken, SC Shaw AREVA MOX Services, Under construction LLC Gaseous Diffusion Uranium Enrichment Facilities Paducah, KY USEC Inc. Active Piketon, OH USEC Inc. In cold shutdown Gas Centrifuge Uranium Enrichment Facilities Piketon, OH USEC Inc. In construction Eunice, NM Louisiana Energy Services Active Idaho Falls, ID AREVA Enrichment Services Under review continued
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24 ANALYSIS OF CANCER RISKS Index Licensee, State 1 Crow Butte Resources, Inc., Nebraska Figure 1.1b.eps 2 Uranium One, Wyoming 3 Power Resources, Inc, Wyoming bitmap 4 Uranium One, Wyoming Kennecott Uranium Corp.,a Wyoming 5 6 Honeywell International, Inc, Illinois 7 Global Nuclear Fuels-Americas, LLC, North Carolina 8 Westinghouse Electric Company, LLC Columbia Fuel Fabrication Fac., South Carolina 9 Nuclear Fuel Services, Inc., Tennessee 10 B&W Nuclear Operations Group, Virginia 11 AREVA NP, Inc., Washington 12 USEC Inc., Kentucky 13 Louisiana Energy Services, New Mexico aStandby FIGURE 1.1b Currently operating USNRC-licensed nuclear fuel-cycle facilities in the United States. comparisons are made (e.g., for multiple cancer types) as well as “false negative” associations (i.e., associations not established because statistical power is low) because effect size is small. There is little way of knowing whether any such associations (or lack of associations) are anything more than statistical effects. On the other hand, epidemiologic studies provide the most direct evi- dence for associations between suspected risk factors (e.g., radiation) and disease (e.g., cancer). Perhaps for this reason, epidemiologic studies con- tinue to be used to assess cancer risks in populations near nuclear facilities in other countries (see Section 1.2 in this chapter and Appendix A). A well-
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25 INTRODUCTION designed epidemiologic study can be used to formulate or test hypotheses about cancer risks in populations around nuclear facilities. The committee received two somewhat conflicting messages from pre- senters at its information-gathering meetings (see Section 1.4 in this chap- ter) and peer reviewers for this report: (1) A Phase 2 epidemiologic study should be carried out; (2) the study will be a “political” rather than a “scientific” exercise. The committee has endeavored to recommend a tech- nically sound approach for carrying out an epidemiologic study while at the same time clearly identifying the challenges for assessing cancer risks at low doses. The committee hopes that the USNRC will be able to use this information to help make an informed decision about whether to undertake a new epidemiologic study and what type of study to conduct. 1.2 PREVIOUS STUDIES OF CANCER RISKS Concerns about the potential health impacts from living near nuclear facilities are not new or unique to the United States. A British television program in 1983 reported a cluster of childhood leukemia in Seascale, a village located on the coast of the Irish Sea about 3 kilometers from the nuclear fuel reprocessing facility at Sellafield. The television program re- ported on seven childhood leukemia cases in the village over the previous 30 years, whereas fewer than one case was expected (Urquhart et al., 1984). Given the proximity of the village to Sellafield, and the absence of other obvious causative agents, radioactive discharges from the reprocessing plant were hypothesized to be responsible for the excess leukemia. The British government appointed an independent advisory group to investigate these claims. The group (Black, 1984) confirmed the leukemia cluster but could not link it to radioactive discharges. A governmental Com- mittee on Medical Aspects of Radiation in the Environment (COMARE) was subsequently established in 1985 to undertake further investigations. To date, this committee has published 14 reports using data from the na- tional registry of children’s tumors (see Appendix A for literature review). Since 1985, epidemiologic studies of cancer risks in populations near nuclear facilities have been carried out in at least 11 countries.6 The major- ity of these studies investigated rates of cancer deaths or cancer occurrence in populations living in various-size geographic areas including counties and municipalities, zones of increasing distance, or zones based on models of dispersion of releases from the nuclear facilities (see Table 4.2, Chap- ter 4). These studies have come to different conclusions, with some suggest- ing a positive association between living in proximity to a nuclear facility 6 Canada, Finland, France, Germany, Great Britain, Israel, Japan, Spain, Sweden, Switzer- land, and the United States.
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26 ANALYSIS OF CANCER RISKS and cancer risk. However, studies have been unable to attribute positive associations to radioactive releases from the facilities. A widely publicized study with a positive finding is the German Kinder- krebs in der Umgebung von Kernkraftwerken (KiKK) study, which was carried out by researchers from the German Childhood Cancer Registry in Mainz on behalf of the Federal Office of Radiation Protection. Study re- sults were published in 2008 (Kaatsch et al., 2008; Spix et al., 2008). They indicated that for a child of age 0-5 years, the risk of developing leukemia doubles if that child lives in close vicinity of a nuclear plant. However, the methodology, presentation, and interpretation of results from the study have been strongly criticized by others (COMARE, 2011; Kinlen, 2011). Additional information about these studies is provided in Appendix A. Results from two other epidemiologic studies were published during this Phase 1 study: the 14th report of COMARE, which provided further consideration of the incidence of childhood leukemia around nuclear plants in Great Britain (COMARE, 2011), and a study on the risk of childhood leukemia and all childhood cancers in the vicinity of Swiss nuclear plants (Spycher et al., 2011). Neither provided significant evidence of a positive association between distance from nuclear plants and cancer risk. A third report from France showed that children living within 5 kilo- meters of nuclear plants are twice as likely to develop leukemia compared to those living 20 kilometers or farther away from the plants. However, analysis of the same population of children using a dose-based geographic zoning approach, instead of distance, did not support the findings. The authors suggest that the absence of any association with the dose-based geographic zoning approach may indicate that the observed association of distance and cancer risk may be due to some unidentified factors other than the releases from the nuclear power plants (Sermage-Faure et al., 2012). Current joint efforts from France and Germany are focusing on develop- ing studies that would improve understanding of the positive associations between childhood leukemia and distance from nuclear power plants by improving current knowledge on the etiology of the disease. Epidemiologic studies of cancer risks in populations near nuclear facili- ties have used a number of approaches to assess exposures of study popu- lations to radiation from facility releases (see Section 4.2.1 in Chapter 4). In most cases, exposures are based on surrogate measures (e.g., distance from a facility) that are not related to quantifiable radiation doses. How- ever, some recent studies have attempted to obtain dose estimates based on facility effluent releases. Evrard et al. (2006) grouped communes within 40 kilometers of nuclear plants in France into five categories based on esti- mated doses based on airborne radioactive effluent discharges (see Chapter 2) and local climate data. The Nuclear Safety Council and the Carlos III
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27 INTRODUCTION Institute of Health (2009) estimated effective doses in populations living in municipalities at various distances from nuclear facilities in Spain. More detailed dose reconstructions have been carried out for other ap- plications. These include reconstruction of doses for World War II atomic bombing survivors in Japan; U.S. military personnel exposed to radiation from atmospheric nuclear-weapons testing; U.S. Department of Energy workers who were exposed to occupational radiation at nuclear weapons production and testing facilities and residents in nearby states who were exposed to radiation that was released from these facilities; and individuals who responded to the 1986 Chernobyl accident. These dose reconstruction efforts are described in a number of reports; see, for example, NCRP (2009) and NAS (1995). 1.3 STRATEGY TO ADDRESS THE STUDY CHARGE This study was carried out by a committee of experts appointed by the NAS. The committee consists of 20 members with expertise that spans the disciplines relevant to the study task: biostatistics, contaminant fate and transport, environmental exposure monitoring, epidemiology, medicine, public health, radiation dosimetry, radiobiology, social science and risk communication, and toxicology. In selecting the committee, the NAS sought to obtain a balance between experts in the design and execution of risk as- sessment studies for low-dose radiation exposures and experts with relevant disciplinary expertise but no direct experience with low-dose radiation risk assessment. Biographical sketches of the committee members are provided in Appendix B. The committee was tasked to recommend appropriate study design(s) to assess cancer risks associated with living near nuclear facilities. The selec- tion of suitable study designs primarily involved judgments about scientific soundness, data availability and accessibility, and level of effort versus likely scientific return. The committee’s judgments were also informed by information that it received from technical experts (see Appendix C) and comments from the public (see Chapter 5). The committee attempted to identify study approaches that were scientifically sound and that addressed public concerns. The focus for this study is on cancer risks arising from exposures to radiation from nuclear plants and fuel-cycle facilities past and present in the course of their ordinary day-to-day operations. The study is not focused on risks arising from nuclear accidents (e.g., Chernobyl or, more recently, Fukushima). Nevertheless, the committee recognizes that public percep- tions about the risks related to nuclear plants and fuel-cycle facilities may be shaped by these events.
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28 ANALYSIS OF CANCER RISKS One of the scientific challenges for carrying out assessments of cancer risks in populations near nuclear facilities is the lack of sufficient statistical power7 to detect relatively small associations between cancer incidence or mortality and exposures to radiation from facility releases. This is primarily the result of the small radiation doses that are typically received by indi- viduals living near nuclear facilities as a result of normal operations at those facilities (see Chapter 3). As a consequence, epidemiologic assessments of cancer risk require the study of very large populations to have any hope of having adequate statistical power to detect positive associations between cancer and radiation exposure. Modest improvements in the statistical power can be achieved by examining dose-response gradients, especially when the population under study is exposed to a range of doses. Tables 1.3 and 1.4 show the populations living within 5 and 30 miles of currently operating nuclear facilities in the United States as determined in the 2010 census.8 As can be seen in this table, there was a wide variation in the numbers of persons living near nuclear facilities in 2010: • Approximately 1 million people lived within 5 miles of operating nuclear plants in 2010; over 45 million people lived within 30 miles. • Approximately 116,000 people lived within 5 miles of USNRC- licensed operating fuel-cycle facilities in 2010; over 2 million peo- ple lived within 30 miles. • Approximately 210 people lived within 5 miles of a USNRC- licensed operating in situ recovery or conventional uranium mill recovery facility in 2010; about 11,000 lived within 30 miles.9 The committee decided to focus most of its efforts in this Phase 1 study on nuclear plants because of their large associated populations. The com- mittee decided not to consider mining and milling facilities in this Phase 1 study because of their low associated populations. The committee recog- nizes that people who live near these mining and milling facilities may be just as concerned about cancer risks as people who live near nuclear plants. However, epidemiologic studies of cancer risk would have no statistical 7 That is, the ability of a statistical test to detect a predetermined difference in risk (e.g., a doubling in cancer mortality associated with radiation exposure) if it exists. In this context, statistical power depends on the risk in the control population, the smallest increase in risk the investigator wants to be reasonably sure of finding (if it is present), and the acceptable probabilities of a false positive result (if there is no increase) and a false negative result (if there is an increase of at least the size to be sought). 8 The 2010 census data are used here simply to illustrate population differences for various facilities. The 2010 data do not reflect the population distribution around sites in prior years. 9 Note: These are median estimates for individual in situ recovery or conventional uranium mill recovery facilities, not total populations for all facilities.
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29 INTRODUCTION TABLE 1.3 Populations in the 5- and 30-Mile (Approximately 8- and 50-Kilometer) Zones around Currently Operating Nuclear Power Plants Based on the 2010 U.S. Census Data Index State Name 5 Mile 30 Mile 1 Alabama Browns Ferry Nuclear Plant 6,098 530,011 2 Joseph M Farley Nuclear Plant 2,534 186,768 3 Arizona Palo Verde Nuclear Generating Station 1,117 273,806 4 Arkansas Arkansas Nuclear One 14,177 137,107 5 California Diablo Canyon Power Plant 1,648 338,602 6 San Onofre Nuclear Generating Station 23,525 2,410,113 7 Connecticut Millstone Power Station 53,321 667,492 8 Florida Crystal River Nuclear Generating Plant 6,142 271,625 9 St. Lucie Plant 34,017 584,465 10 Turkey Point 7,963 1,838,689 11 Georgia Edwin I. Hatch Nuclear Plant 2,063 135,568 12 Vogtle Electric Generating Plant 1,941 398,181 13 Illinois Braidwood Station 16,834 971,587 14 Byron Station 12,339 600,581 15 Clinton Power Station 1,643 419,698 16 Dresden Nuclear Power Station 22,872 1,815,892 17 LaSalle County Station 3,211 345,966 18 Quad Cities Nuclear Power Station 6,252 451,281 19 Iowa Duane Arnold Arnold Energy Center 12,180 351,236 20 Kansas Wolf Creek Generating Station 1,690 75,810 21 Louisiana River Bend Station 5,647 536,645 22 Waterford Steam Electric Station 13,774 1,119,079 23 Maryland Calvert Cliffs Nuclear Power Plant 18,438 443,962 24 Massachusetts Pilgrim Nuclear Power Station 23,108 1,245,016 25 Michigan Donald C. Cook Nuclear Plant 16,977 563,815 26 Palisades Nuclear Plant 7,693 288,716 27 Fermi 18,035 2,230,762 28 Minnesota Monticello Nuclear Generating Plant 21,107 964,863 29 Prairie Island Nuclear Generating Plant 6,650 789,039 30 Mississippi Grand Gulf Nuclear Station 1,657 87,677 31 Missouri Callaway Plant 1,620 225,301 32 Nebraska Cooper Nuclear Station 892 54,338 33 Fort Calhoun Station 9,305 829,567 34 New Seabrook Station 47,004 1,667,009 Hampshire continued
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30 ANALYSIS OF CANCER RISKS TABLE 1.3 Continued 35 New Jersey Hope Creek Generating Station 5,681 1,512,768 36 Oyster Creek Nuclear Generating Station 44,156 1,010,661 37 Salem Nuclear Generating Station 5,434 1,490,771 38 New York James A. Fitzpatrick Nuclear Power 10,838 615,046 Plant 39 R.E. Ginna Nuclear Power Plant 14,788 894,227 40 Indian Point Nuclear Generating 88,189 5,695,758 41 Nine Mile Point 6,729 307,622 42 North Carolina Brunswick Steam Electric Plant 13,398 315,360 43 McGuire Nuclear Station 51,561 2,014,369 44 Shearon Harris Nuclear Power Plant 29,445 1,567,691 45 Ohio Davis-Besse Nuclear Power Plant 3,390 733,031 46 Perry Nuclear Power Plant 24,164 810,777 47 Pennsylvania Beaver Valley Power Station 16,181 1,656,510 48 Limerick Generating Station 97,649 4,453,399 49 Peach Bottom Atomic Power Station 11,326 1,787,122 50 Susquehanna Steam Electric Station 15,462 664,767 51 Three Mile Island Nuclear Station 48,714 1,520,777 52 South Carolina Oconee Nuclear Station 15,616 634,339 53 H.B. Robinson Steam Electric Plant 11,927 292,920 54 Virgil C. Summer Nuclear Station 2,940 663,629 55 Catawba Nuclear Station 50,337 1,768,246 56 Tennessee Sequoyah Nuclear Plant 29,485 714,473 57 Watts Bar Nuclear Plant 5,152 362,142 58 Texas Comanche Peak Nuclear Power Plant 6,842 285,159 59 South Texas Project 1,691 66,066 60 Vermont Vermont Yankee Nuclear Power Station 12,737 345,863 61 Virginia North Anna Power Station 6,903 507,945 62 Surry Power Station 13,081 984,927 63 Washington Columbia Generating Station 407 282,505 64 Kewaunee Power Station 2,974 324,911 65 Wisconsin Point Beach Nuclear Plant 3,297 304,151 Total: 934,488 45,020,247 NOTE: Plants in close geographic proximity may have overlapping populations, so persons living near those plants could be included (i.e., counted) in more than one plant population. The population total shown at the bottom of the table corrects for multiple counting (i.e., each person living near a plant is only counted once). As a consequence, the sum of the popula- tions for the individual plants does not equal the population total at the bottom of the table.
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31 INTRODUCTION TABLE 1.4 Populations in the 5- and 30-Mile (Approximately 8- and 50-Kilometer) Zones around Currently Operating USNRC-Licensed Facilities that Are Part of the Nuclear Fuel Cycle Based on the 2010 U.S. Census Data Index State Licensee Type 5 mile 30 mile 1 Nebraska Crow Butte Resources, Inc Mining 196 10,796 2 Wyoming Uranium One Mining 237 5,986 3 Power Resources, Inc Mining 72 14,378 4 Uranium One Mining 123 5,340 Kennecott Uranium Corp.a 5 Wyoming Milling 21 1,438 6 Illinois Honeywell International, Conversion 11,334 184,442 Inc 7 North Carolina Global Nuclear Fuels- Fuel 35,854 349,780 Americas, LLC Fabrication 8 South Carolina Westinghouse Electric Fuel 14,512 796,391 Company, LLC Fabrication Columbia Fuel Fabrication Fac. 9 Tennessee Nuclear Fuel Services, Inc. Fuel 12,765 432,825 Fabrication 10 Virginia B&W Nuclear Operations Fuel 21,810 280,396 Group Fabrication 11 Washington AREVA NP , Inc. Fuel 33,253 276,038 Fabrication 12 Kentucky USEC Inc. Enrichment 7,370 190,772 13 New Mexico Louisiana Energy Services Enrichment 934 48,631 Total: 116,282 2,308,747 NOTE: Facilities in close geographic proximity may have overlapping populations, so persons living near those facilities could be included (i.e., counted) in more than one facility popula- tion. The population total shown at the bottom of the table corrects for multiple counting (i.e., each person living near a facility is only counted once). As a consequence, the sum of the populations for the individual facilities does not equal the population total at the bottom of the table. aStandby
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32 ANALYSIS OF CANCER RISKS power to detect associations between radiation and cancer because of these small populations. With respect to the other types of fuel-cycle facilities, the committee focused most of its efforts on one facility, Nuclear Fuel Services in Erwin, Tennessee, primarily because of the public interest in cancer risks resulting from radioactive releases from that facility. The methodology proposed by the committee for assessing cancer risk at this facility is applicable to other fuel-cycle facilities as well. 1.4 INFORMATION GATHERING AND REPORT ORGANIZATION The committee held five information-gathering meetings to receive briefings from subject-matter experts, including experts in the fields of epidemiology, dosimetry, and social science; representatives of the USNRC and the nuclear industry; representatives of cancer registries; and interested members of the public. Small groups of committee members visited the Dresden Nuclear Power Station (Illinois) in April 2011, the San Onofre Nuclear Generating Station (California) in July 2011, and the Nuclear Fuel Services facility (Tennessee) in October 2011 to learn about the design and operation of these facilities’ radioactive effluent release and environmental monitoring programs. A list of committee meeting briefings is provided in Appendix C. The committee’s information-gathering sessions were webcast in an effort to enhance public awareness and participation in the study. Cop- ies of these webcasts are available at http://www.nationalacademies.org/ cancerriskstudy. The committee received a large number of oral and written comments from nongovernmental organizations and other members of the public. These were helpful for informing the committee about public concerns related to the study and for uncovering data sources and documents that were useful to the committee. This report is organized into five chapters that address the statement of task (Sidebar 1.1) in its entirety: • Chapter 1 (this chapter) provides background on the study. • Chapter 2 describes the effluent releases from nuclear facilities. • Chapter 3 describes methods to estimate radiation exposure and dose from radioactive effluent releases and other sources. • Chapter 4 describes epidemiologic study designs that could be used to investigate whether populations near nuclear facilities are at an increased risk of developing cancer. • Chapter 5 describes the public engagement process used in this Phase 1 study and suggests how it can be extended for Phase 2.
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33 INTRODUCTION Definitions of terms and acronyms are provided in Appendixes N and O, respectively. REFERENCES Black, D. (1984). Investigation of the possible increased incidences of cancer in West Cumbria. London: Her Majesty’s Stationary office. COMARE (Committee on Medical Aspects of Radiation in the Environment) (2011). Four- theenth report: Further consideration of the incidence of childhood leukemia around nuclear power plants in Great Britain, Health Protection Agency, may 2011. Evrard, A. S., D. Hemon, et al. (2006). Childhood leukaemia incidence around French nuclear installations using geographic zoning based on gaseous discharge dose estimates. Br J Cancer 94(9):1342-1347. Jablon, S., Z. Hrubec, J. D. Boice, Jr., and B. J. Stone (1990). Cancer in populations living near nuclear facilities, Volumes 1-3, NIH Publication No. 90-874. Jablon, S., Z. Hrubec, et al. (1991). Cancer in populations living near nuclear facilities. A survey of mortality nationwide and incidence in two states. JAMA 265(11):1403-1408. Kaatsch, P., C. Spix, et al. (2008). Leukaemia in young children living in the vicinity of German nuclear power plants. Int J Cancer 122(4):721-726. Kinlen, L. (2011). A German storm affecting Britain: Childhood leukaemia and nuclear power plants. J Radiol Prot 31(3):279-284. NAS (National Academy of Sciences) (1995). Radiation dose reconstruction for epidemiologic uses. Washington, DC: National Academy Press. NCRP (National Council on Radiation Protection and Measurements) (2009). Ionizing radia- tion exposure of the populations of the United States. Report 160. Nuclear Safety Council and the Carlos III Institute of Health (2009). Epidemiological study of the possible effect of ionizing radiations deriving from the operation of Spanish nuclear fuel cycle facilities on the health of the population living in their vicinity, Spain. ORISE (Oak Ridge Institute for Science and Education) (2009a). Protocol for an analysis of cancer risk in populations living near nuclear-power facilities, Rev. 1, September 30. ORISE (2009b). Cancer incidence feasibility study, October 22. Sermage-Faure, C., D. Laurier, S. Goujon-Bellec, M. Chartier, A. Guyot-Goubin, J. Rudant, D. Hémon, and J. Clavel. Childhood leukemia around French nuclear power plants—the Geocap study, 2002-2007. Int J Cancer. [Epub ahead of print] Spix, C., S. Schmiedel, et al. (2008). Case-control study on childhood cancer in the vicinity of nuclear power plants in Germany 1980-2003. Eur J Cancer 44(2):275-284. Spycher, B. D., M. Feller, et al. (2011). Childhood cancer and nuclear power plants in Swit- zerland: a census-based cohort study. Int J Epidemiol 40(5):1247-1260. Urquhart, J., M. Palmer, et al. (1984). Cancer in Cumbria: The Windscale connection. Lancet 1(8370):217-218. USNRC (U.S. Nuclear Regulatory Commission) (2011). 2011-2012 Information Digest. NUREG-1350, Vol. 23.
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