|
Items in cart [0] |
Questions? Call 888-624-8373 |
| Copyright © 2009. National Academy of Sciences. All rights reserved. Terms of Use and Privacy Statement |
Below are the first 10 and last 10 pages of uncorrected machine-read text (when available) of this chapter, followed by the top 30 algorithmically extracted key phrases from the chapter as a whole.
Intended to provide our own search engines and external engines with highly rich, chapter-representative searchable text on the opening pages of each chapter.
Because it is UNCORRECTED material, please consider the following text as a useful but insufficient proxy for the authoritative book pages.
Do not use for reproduction, copying, pasting, or reading; exclusively for search engines.
OCR for page 13
1
Introduction
The charge to the committee was to study possible approaches for releasing
slightly radioactive solid material from U.S. Nuclear Regulatory Commission
(USNRC)-licensed facilities. Accordingly, the analyses in the first nine chapters
and the recommendations in Chapter 10 pertain primarily to slightly radioactive
solid materials currently under the regulatory control of the USNRC or agree-
ment states.1
The term "slightly radioactive solid material" (SRSM) refers to material that
contains radionuclides from licensed sources used or possessed by licensees of
the USNRC and agreement states. These materials typically contain low concen-
trations of radionuclides and, by virtue of these low concentrations, can be con-
sidered for disposition as something other than low-level radioactive waste
(LLRW).2
1Section 274 of the Atomic Energy Act (AEA) authorizes the Commission to enter into an effec-
tive agreement with the governor of a state to allow that state to assume the USNRC's authority to
regulate certain types of materials licensees only. Reactor licensees remain the exclusive domain of
the USNRC. Today there are 32 agreement states, which have implemented regulatory programs that
are compatible with the USNRC's programs. The materials licensees that a state can regulate include
those that use or possess source material, byproduct material, or special nuclear material in quantities
not sufficient to form a critical mass (e.g., less than 350 grams of uranium-235).
2LLRW is waste that contains concentrations of radioactive materials that are regulated under 10
CFR Part 61. There is no low-end cutoff for the concentrations of radioactive materials regulated as
LLRW.
13
OCR for page 14
14
THE DISPOSITION DILEMMA
This chapter begins with the historical context for current USNRC regula-
tions pertinent to the release of solid materials from licensed facilities. Next is a
review of approaches used by other agencies for release (removal) of radioactive
materials from regulatory control and a summary of the current process by which
the USNRC decides on the release of solid materials using a case-by-case ap-
proach. The chapter concludes with a summary of the committee's task (the full
text of the statement of work can be found in Appendix C) and a synopsis of the
role each chapter plays in fulfilling that task.
HISTORICAL CONTEXT
The USNRC's basic standards for protection against radiation are set forth in
10 CFR Part 20,3 a regulation intended ". . . to control the receipt, possession,
use, transfer, and disposal of licensed material...." This regulation was first
issued as a final regulation by the Atomic Energy Commission (AEC) in 1957
and was used for many years with minor amendments. The 1957 version of 10
CFR Part 20 contains a short section on waste disposal that provides the basis for
case-by-case review of disposal procedures not covered within the two succeed-
ing sections that deal with disposal of tritium and carbon-14 in sewerage systems
or in soil. The 1957 regulation did not include criteria specifying an amount or
concentration of a radionuclide in a solid material,4 below which the solid mate-
rial would be exempt from regulatory control or conditional clearance (Box 1-1~.5
However, pursuant to Section 2002 of 10 CFR Part 20, added in a later revision of
the regulation, the USNRC and agreement states evaluate requests by licensees
for permission to release solid materials on a case-by-case basis, using existing
regulatory guidance.6 The situation for gaseous and liquid materials is different,
3References to the United States Code of Federal Regulations (CFR) will be given using the
conventional format with the code title (here, Title 10) followed by the acronym CFR and the part or
chapter number(s).
4For two radionuclides, in one specific application, Part 20 does contain release criteria for solid
materials. These criteria allow disposal of volume-contaminated animal tissue containing less than
1.85 ksqlg of 3H or 14c as if it were not radioactive.
5The definitions of terms related to release of materials from regulatory control are presented in
Box 1-1. The committee notes much confusion about the common usage of terms in discussion of the
release of radioactive materials. Without necessarily affirming this approach, the committee decided
to use the terms as defined in the American National Standards Institute-Health Physics Society
(ANSI/HPS, 1 999) Standard N 13. 12-1999.
6The 1957 issue of Part 20 had a short section on waste disposal that included Part 20.302,
``Method for obtaining approval of proposed disposal procedures,,, the basis for case-by-case review
of disposal procedures not authorized by the two succeeding sections on disposal in sewerage sys-
tems or in soil. The original Part 20 gave general requirements for waste disposal of byproduct
material. The 1957 standard did not include any criteria for a floor to the amount or concentration of
controlled radionuclides, which criteria might be used as the basis for exemption of waste from
regulatory control.
OCR for page 15
INTRODUCTION
15
OCR for page 16
16
THE DISPOSITION DILEMMA
and Part 20 does set limits on the amount or concentration of a radionuclide in
such materials that may be released to the environment from a nuclear facility.
These concentration limits, which have been set for essentially all radionuclides
of concern (numbering in the hundreds), are based on calculated dose to the
general public. Volume-contaminated facility structures and soils that remain at
decommissioned sites are regulated under Part 20, Subpart E, which establishes
criteria for unrestricted use.
In June 1974 the AEC issued Regulatory Guide 1.86, Termination of Oper-
ating Licenses for Nuclear Reactors (AEC, 1974~. This guide provides four
alternatives for retiring a reactor facility at the end of its operational life. After
the facility or equipment has been decontaminated and if the residual surface
radiation levels do not exceed the limits stated in Table I of Regulatory Guide
1.86, the licensee may release the equipment or the USNRC may authorize
termination of the facility license. Ever since the guide was issued, Table I has
been used as a basis for releasing surface-contaminated material from further
regulatory control when appropriate for example, when incorporated into the
conditions of a license.
In 1991 the USNRC, as the successor agency to the AEC for regulating
nuclear facilities, issued a major revision to 10 CFR Part 20. The stated purpose
of this revision was ". . . to modify the [US]NRC's radiation protection standards
to reflect developments in the principles and scientific knowledge underlying
radiation protection that have occurred since Part 20 was originally issued more
than 30 years ago" (USNRC, l991c). The revision also discusses its relationship
to the recommendations of the International Commission on Radiological Protec-
tion (ICRP) and its U.S. counterpart, the National Council on Radiation Protec-
tion and Measurements (NCRP). Information was provided about the revisions to
the Federal Radiation Protection Guidance on Occupational Exposure which
incorporate the philosophy and methodology of ICRP Parts 26 and 30 and the
recently issued revisions in NCRP Report 91 (NCRP,1987c) of the 1971 recom-
mendations on radiation protection limits. The recommendation in NCRP Report
91 for a negligible individual risk level of 1 mrem/yr (0.01 mSv/yr) was recog-
nized but not adopted by the USNRC for procedural reasons (NCRP Report 91
was issued after the proposed Part 20 rule, and there had been no opportunity for
public comment). Box 1-2 contains definitions of the units of measurement used
in this report.
The 1991 revision to 10 CFR Part 20 included other references on radiation
protection, including a 1988 report of the United Nations Scientific Committee
on the Effects of Atomic Radiation (UNSCEAR, 1988), reports by committees of
the National Research Council (NRC, 1990) on the Biological Effects of Ionizing
Radiation (BEIR), and the 1990 recommendations of the ICRP (ICRP, 1990~.
The 1991 revision also included allowable limits on the radiation dose that an
OCR for page 17
INTRODUCTION
17
individual could receive from exposure to radioactive materials (dose limits) and
the concentration limits for radioisotopes released in gaseous or liquid effluents.
Even before the 1991 revision to Part 20 was issued, the USNRC, interna-
tional governments, and non-U.S. agencies had agreed on a principal dose limit
for members of the public of 100 mrem/yr, rather than the old limit of 500 mrem/
yr. Although the USNRC has agreed to this dose limit set by the ICRP, the U.S.
Environmental Protection Agency (EPA) has not yet done so (ICRP, 1985;
USNRC, l991c). This exposure limit was chosen with the recognition that the
average exposure due to natural background radiation had been estimated at 240
mrem/yr by UNSCEAR and 300 mrem/yr by NCRP (UNSCEAR, 1982; NCRP,
1987a). In revising Part 20, the USNRC recognized that "when application of the
dose limits is combined with the principle of keeping all radiation exposures 'as
low as is reasonably achievable' [ALARA] the degree of protection could be
significantly greater than from relying upon the dose limits alone." Part 20 as
revised sets dose limits compatible with ALARA.
In issuing a standard for the uranium fuel cycle, the EPA allocated a public
exposure limit of 25 mrem/yr, whole-body effective dose,7 to the fuel cycle (40
CFR Part 190~. All of the regulatory bodies use these exposure limits in the
context of the three principles of radiation protection:
1. Justification of a practice;
2. Optimization (USNRC makes explicit use of ALARA exposures held
as low as is reasonably achievable);8 and
3. Limitation of individual risk through exposure limits.
In the text of the revised 10 CFR Part 20, the USNRC recognized that the ALARA
standard for reactor effluent releases, combined with the EPA fuel cycle standard,
in effect set a limit on exposure of the general public to radioactive effluents that
was only a few percent of the USNRC dose limit of 100 mrem/yr.
Optimization through an ALARA standard is central to the USNRC's radia-
tion protection strategy. The objective is not merely to meet the dose limit but to
go below it as far as is reasonably achievable. One way to address the possibility
of doses to some members of the general public arising from multiple exposures
to different clearance practices is to rely on the unquantified margin induced by
7Also included in this standard were limits of 75 mrem effective dose to the thyroid and 25 mrem
effective dose to any one organ. The system of effective dose predates the system of dose equivalent
now in widespread use, and the two are not directly comparable. The EPA has equated 25 mrem/yr
whole-body effective dose to 15 mrem/yr dose equivalent (58 Federal Register 66398-66416; De-
cember 20, 1993).
8The EPA does not apply the optimization principle in the same way that the USNRC does. The
EPA implements this principle broadly within its multistatute mission.
OCR for page 18
18
THE DISPOSITION DILEMMA
an ALARA standard.9 Another approach is to allocate a fractional part of the dose
limit to a practice, as EPA did in the facility standard for the uranium fuel cycle.
Along with establishing a dose limit for individual members of the public,
the Part 20 revision for decommissioning allocated a significant fraction of the
general limit to individual facilities. This approach appears reasonable, since it is
difficult to envision that more than a few facilities would simultaneously be the
source of significant exposure to any member of the public because the facilities
are at fixed sites.
The USNRC has tried previously to set standards for release of SRSM from
regulatory control. A proposed rule (45 Federal Register 70874; October 27,
9The USNRC regularly applies ALARA with protection limits but recognizes that the margin
induced by ALARA can vary widely from case to case for example, the contrast in site decommis-
sioning between users of sealed sources and users of unsealed quantities of radioactive materials (59
Federal Register 43208). Also, the ALARA concept would become irrelevant at the proposed de
minimis levels of clearance standards.
OCR for page 19
INTRODUCTION
19
1980) to exempt residual levels of radionuclides in smelted alloys from licensing
was withdrawn in 1986 (51 Federal Register 8842; March 14, 1986~. A more
sweeping policy issued by the USNRC, as directed by the Low Level Radioactive
Waste Policy Amendments Act of 1985 (LLWPAA), declared materials with low
concentrations of radioactivity contamination to be "below regulatory concern"
(BRC) and hence deregulated (55 Federal Register 27522; July 3, 1990~. How-
ever, Congress intervened to set aside the BRC policy in the Energy Policy Act of
1992 after the USNRC's own suspension of the policy (56 Federal Register
36068; July 30, 1991~. Circumstances considered for clearance (unrestricted re-
lease) include materials in which radioactive contamination is so low that clear-
ance is warranted. In contrast to the release of a material from regulatory control,
exemption from control may be considered in some circumstances, for example,
when a small amount of radioactive material is added to a product deliberately to
serve some justified purpose.
To account for different possible exposures, the exposure limit set for clear-
ance (i.e., unrestricted release) or exemption of a material would have to be a
OCR for page 20
20
THE DISPOSITION DILEMMA
small fraction of the 100 mrem/yr total limit. The revised Part 20 did not include
specific standards for exemption; for case-by-case review, it is identical to the
previous version. The 1991 version of Part 20 contains no regulatory statement
defining a floor for regulated radionuclide content, other than the reference (noted
above) to the NCRP recommendation on negligible individual risk of 10 pSv/yr
(1 mrem/yr).
RADIATION PROTECTION STANDARDS DEVELOPED BY
ORGANIZATIONS OTHER THAN THE USNRC
Organizations in Europe have developed basic radiation safety standards.
Beginning in 1982, the International Atomic Energy Agency (IAEA) published a
number of recommendations. Appendix C reviews IAEA Safety Series 89 along
with safety standards developed by a number of other agencies. All of these
standards recommend an individual dose on the order of 10 pSv/yr (1 mremlyr) as
the basis for clearance of materials from regulatory control.
Dose Comparisons
Standards for releasing SRSM are often based on a small percentage of the
dose that a member of the U.S. population receives from what is termed back-
ground radiation (see definitions in Box 1-1~. Table 1-1 lists the average annual
dose to an individual in the United States from both natural and anthropogenic
~ . . . .. .
sources of Ionizing ramahon.
The values in Table 1-1 are averages, and the levels of background radiation
are not uniform for individuals in different locations and having different life-
styles (see Table 1-2~. A person living at higher altitudes receives more cosmic
radiation than someone living near sea level. (For example, a person living in
Denver, Colorado, receives 200 pSv/yr [20 mrem/yr] more than a person living
on the Atlantic Seaboard, but when all natural sources are included the difference
is 600 pSv/yr [60 mrem/yr] [NCRP, 19931.) A person living in a brick house
receives an annual dose that is 70 pSv (7 mrem) higher than the dose for a person
living in a frame house. An individual flying across the country receives a dose of
about 25 pSv (2.5 mrem) per flight.
THE U.S. AND GLOBAL CONTEXTS OF
RADIOACTIVE WASTE GENERATION
The ionizing radiation from radioactive materials has been used for more
than a century. X rays and radium were soon used in the radiation treatment of
cancer. Nuclear medicine followed, when radioactive tracers became available in
1931, after the development of the cyclotron. Nuclear weapons were developed
during World War II, and the industrial processes involved also produced large
quantities of radionuclides with long half-lives. Nuclear power plants to generate
OCR for page 21
INTRODUCTION
TABLE 1-1 Average Annual Amounts of Ionizing Radiation to Which
Individuals in the United States Are Exposed
21
Dose
Source mSv/yr mrem/yr Percent of Total Dose
Natural
Radon 2.0 200 55
Cosmic 0.27 27 8
Terrestrial 0.28 28 8
Internal 0.39 39 11
Total Natural 3.0 300 82
Anthropogenic
Medicala
X-ray diagnosis 0.39 39 11
Nuclear medicine 0.14 14 4
Consumer products 0.10 10 3
Occupational <0.01 <1.0 <0.03
Nuclear fuel cycle <0.01 < 1.0 <0.03
Nuclear fallout <0.01 < 1.0 <0.03
Miscellaneous <0.01 <1.0 <0.03
Total anthropogenic 0.63 63 18
Total natural and anthropogenic 3.6 360 100
SOURCE: NCRP (1987a).
tries.
aUNSCEAR (2000) reports 1.2 mSv as the average medical dose for health care level I coun-
TABLE 1-2 Common Sources of Radiation to Which the Public Is Exposed
Source
Dose Equivalent
(,uSv) (mrem)
One-way, transcontinental or trans-atlantic airplane flight at mid-latitudes
Gas mantles (containing thorium), 1 year's typical use
Additional annual dose received from residence in a brick house, versus a
wooden frame house
Annual dose from nuclear power plant to maximally exposed person
(airborne effluents)
Pressurized water reactor
Boiling water reactor
Annual dose received from natural levels of potassium-40 in the body
Additional annual dose from cosmic rays received in Santa Fe, New
Mexico, versus sea level
Additional annual dose from natural background received in Denver,
Colorado, versus Atlantic Seaboard due to all natural sources (cosmic
rays, terrestrial deposits of radionuclides, etc.)
25 (2.5)
2 (0.2)
7o (7)
6 (0~6)
1 (0.1)
180 (18)
450 (45)
600 (60)
SOURCES: NCRP (1987a, 1987b, 1993); NRC (1999).
OCR for page 22
22
THE DISPOSITION DILEMMA
electricity soon followed, and over a period of about 30 years the power industry
added nuclear capacity to coal, natural gas, and other sources of energy used to
generate electricity. In the United States, 103 nuclear power reactor units now
produce about 20 percent of the nation's electricity.
Soon after the United States developed nuclear weapons and nuclear power
reactors, the developed nations in Europe and Asia followed with their own
nuclear development programs. Nuclear power reactors are now used widely to
generate electricity in many countries. (In France, approximately 80 percent of
the electric power requirements are generated with nuclear fuel.) With the global
spread of nuclear weapons and nuclear power, large quantities of radioactive
materials have been generated in both developed and developing countries, and
the global distribution of radioactive material raises important considerations.
With global trade, at least trace amounts of radioactive materials will certainly be
shipped across many borders. Detailed discussion of the international aspects of
clearance regulations can be found in Chapter 7.
Radioactive waste is generated by many different industries and is regulated
within the United States by several federal agencies, with the general exception
of naturally occurring radioactive material (NORM) and naturally occurring and
accelerator-produced radioactive material (NARM).10 The larger sources (gen-
erators) of regulated radioactive materials are listed below:
1. Licensees of the USNRC and agreement states,
2. U.S. Department of Energy (DOE),
3. U.S. Department of Defense (DoD), and
4. Domestic nonnuclear industriesll that nevertheless accumulate process
wastes with significant radioactive material content.
The control and release practices of each of these generators (or generator
categories) are discussed in subsequent subsections. These practices are impor-
tant to considerations of alternative disposition approaches.
The USNRC System
The USNRC regulates radioactive materials through licenses. Among the
licensees are many thousands of small users of sealed sources,l2 about a thousand
10DOE guidance applies to the management of NORM at its own facilities, but the regulation of
NORM and NARM is otherwise performed only by states under applicable state law.
1lBy "nonnuclear industry," the committee means an industry whose processes are neither based
upon nor designed to make use of radionuclide decay or fission reactions. Thus, an industry in which
radioactive material may accumulate as an unsought concomitant of the industrial processes being
used, such as petroleum drilling or phosphate mining, is a nonnuclear industry.
12Sealed sources are byproduct material encased in a capsule to prevent leakage. They typically
contain a concentrated form of one radionuclide (e.g., 137Cs).
OCR for page 23
INTRODUCTION
23
hospitals, 104 licensed nuclear power reactor units (of which 103 are operating),
36 operating nonpower reactor units, 49 fuel cycle facilities, and 5,288 materials
licensees. Agreement states have issued an additional 15,512 materials licenses
(SCA, 2001~. Generation of SRSM is generally not an issue for licensees using
sealed sources provided the sources are maintained in a safe condition and
location.l3 For all licensees, the primary disposal issue is access to disposal
options at reasonable cost. For USNRC licensees, most of the SRSM inventory
(metals, concrete, soils, equipment, etc.) that may undergo clearance is associated
with operating or decommissioning the 104 nuclear power reactor units at 65
sites, which are distributed across the country, with 32 states having one or more
units.
In principle, the schedule for decontaminating and decommissioning a
nuclear power reactor unit is established by the terms of its operating license.
However, because the economics of nuclear power production in the United
States have changed dramatically in recent years for a variety of reasons, the
trend among licensees is to apply for extensions to their licenses. Because the
development of these power plants was closely regulated from the industry's
inception, the location, types, and amounts of contamination associated with
these plants are known.
Procedures for decommissioning reactors have already been established,
based on three options: decontamination, safe storage, or entombment. Some of
the alternative approaches to the disposition of SRSM could facilitate decommis-
sioning by markedly reducing costs.
The DOE System
Inventories of contaminated metal scrap have been identified at 13 DOE
sites. Although not licensed by the USNRC, DOE manages and disposes of a
significant portion of the nuclear material within the United States and is dis-
cussed here to show the broader context for the handling and disposition of such
material. Because most DOE sites were involved in producing enriched uranium
and plutonium, the radioactive materials contain long-lived radionuclides, in-
cluding actinides such as neptunium and americium. DOE operated 14 plutonium
production reactors at the Hanford Site and the Savannah River Site, producing
about 100 tons of 239Pu, which has a half-life of 24,390 years. Chemical separa-
13Although contamination from maintained sealed sources is not an issue, some sealed sources are
lost. If these lost sources, known as orphan sources, enter the scrap metal stream, they pose a serious
problem for the steel industry. Orphan sources in the scrap stream are difficult to detect. If by
accident they are melted into the production stream, major sections of a steel mill can be contami-
nated, causing tens of millions of dollars of damage.
OCR for page 24
24
THE DISPOSITION DILEMMA
tion processes for the recovery of plutonium and uranium generated more than
100 million gallons of radioactive wastes, which are currently stored at several
DOE sites (SCA, 2001~.
The DOE sites are large often measured in hundreds of square miles. For
example, the Hanford Site is about 560 square miles and the Savannah River Site
is approximately 310 square miles. Production facilities at these large sites oc-
cupy only a small fraction of the total site area. Because many of the sites are well
removed from populated areas, long-term on-site storage or burial has been one
option employed for handling wastes. In addition, the Savannah River Site and
the Nevada Test Sitei4 are currently used for disposal of DOE-generated LLRW.
The facilities at most DOE sites are large relative to most industrial plants.
For example, the K-25 gaseous diffusion plant, built in 1943 at Oak Ridge,
Tennessee, is a three-level building that occupies 44 acres. In many instances, the
DOE facilities are no longer functioning but still contain significant amounts of
SRSM. Also, some of the equipment used to produce weapons-grade materials is
classified and must be Reconfigured at secure sites before disposal.
Production activities at many of the DOE sites began in 1943, when the
dangers of ionizing radiation were less well understood or perhaps not of greatest
concern. In a climate of wartime urgency, creating an entirely new and huge
production complex and running it at full capacity were the critical concerns.
Materials were disposed or stored on-site, with limited attention to the safeguards
now taken for granted. Today, cleaning up discarded radioactive materials from
the 1940s and 1950s at many DOE sites poses major problems for the contractors
involved. The projected costs are enormous. Due to the complex history of de-
fense-related operations at DOE facilities, material and waste management prac-
tices varied widely over the past half-century. This history often complicates the
application of criteria for the release of solid materials during decommissioning
of DOE facilities.
The DoD System
The DoD system includes both USNRC-licensed operations, covering a spec-
trum of operations similar to those found in the civilian world, and assets related
to the nuclear Navy. The DoD facilities licensed by the USNRC include hospi-
tals, laboratories, proving grounds, some nuclear reactors, weapons facilities, and
missile launch sites. The USNRC does not license the nuclear Navy's assets,
which include naval nuclear reactors and associated propulsion units. When
nuclear-powered vessels are decommissioned, the reactor compartments are cut
from the hull, sealed, and shipped to the DOE Hanford Site for burial. The ship
i4This site, formerly used for nuclear weapons tests, is the largest in the DOE complex and
occupies about 1,350 square miles in a remote area about 65 miles northwest of Las Vegas.
OCR for page 25
INTRODUCTION
25
hulls are scrapped. The guidelines followed for clearing materials for reuse or
recycle are classified. As of April 1999 the U.S. Navy had shipped 79 reactor
compartment packages (representing 77 submarines and 1 cruiser) to the Hanford
Site for disposal. There are about 2,800 tons of various types of recyclable metals
in a submarine and 6,000 tons in a cruiser (SCA, 2001~. Thus, more than 220,000
tons of steel, aluminum, copper, lead, and other metals have been recycled or
reused from the Navy's decommissioning efforts.
About 115,000 cubic feet of LLRW is generated annually from DoD facili-
ties. Most of this waste is from cleanup efforts rather than operations. As a group,
the USNRC-licensed facilities of DoD appear to raise no unique inventory issues.
Non-USNRC-Licensed Industries
Among the U.S. industries that generate radioactive solids are several that
can be described as nonnuclear because the processes employed do not intention-
ally use nuclear decay or nuclear fission reactions. Among these industries are
petroleum production and refining, phosphate and phosphate fertilizer produc-
tion, coal-fired power plants, and mining. The wastes generated contain NORM
or technically enhanced NORM (TENORM). The USNRC estimates that more
than 2 million metric tons of TENORM are generated annually (USNRC, 2001a).
Much of this material contains significant concentrations of uranium, thorium,
and radium radionuclides, all of which have long half-lives.
There are no federal statutes that specifically establish regulatory control of
TENORM, although some waste streams fall under the jurisdiction of the EPA.
Control of TENORM has been left to the states, and some agreement states
regulate TENORM under their general rules governing the possession of radioac-
tive materials. In many states with agreement state authority, the regulation of
NORM, TENORM, and NARM comes under the same program used to regulate
radioactive materials controlled under the Atomic Energy Act (AEA).
About 75 Superfund sites are contaminated with radioactive wastesl5
(Wolbarst et al., 1999~. Many of these are DoD and DOE sites, but more than 20
were created by commercial industrial waste disposal.
STATUS OF THE CURRENT USNRC PROCESS
FOR CLEARING SOLID MATERIALS
The USNRC has statutory responsibility for the protection of public health
and safety related to the use of source material, byproduct material, and special
15''Superfund'' is the commonly used term for the Comprehensive Environmental Response, Com-
pensation, and Liability Act.
OCR for page 26
26
THE DISPOSITION DILEMMA
nuclear material, as defined by the ALA. The USNRC's regulations in fulfill-
ment of these goals include those on protection against radiation (10 CFR Part 20
et seq.), licensing of byproduct material (10 CFR Part 30 et seq.), licensing of
source material (10 CFR Part 40), licensing of production and utilization facili-
ties (i.e., nuclear reactors; 10 CFR Part 50 et seq.), licensing of special nuclear
material (10 CFR Part 70 et seq.), and so forth.
As noted, the regulations on protection against radiation, 10 CFR Part 20, do
not set predetermined levels on amounts or quantities of radionuclides in solid
materials below which these materials can be released from further regulatory
control. Solid materials potentially available for release from regulatory control
include metals, building concrete, on-site soils, equipment, and furniture used in
routine operation of licensed nuclear facilities. Most of this material will have no
radioactive contamination, but some of it may have surface or volume contami-
nation. Licensees continue to request permission from the USNRC and agree-
ment states to release such solid materials when they are no longer useful or when
the licensed facility is decommissioned, pursuant to Section 2002 of 10 CFR Part
20. In addition, as noted, Regulatory Guide 1.86 (AEC, 1974) contains limits
applicable to surface contamination that are incorporated into license conditions
and allow clearance of SRSM.
The USNRC allows licensees to release solid material according to preestab-
lished criteria. For reactors, if surveys for surface residual radioactivity per-
formed by the licensee on equipment or material indicate the presence of radioac-
tivity above natural background levels, then release is not permissible.~7 If no
such surface activity is detected, then the solid material in question need not be
treated as radioactive material. This approach sometimes leads to subsequent
problems, when detectors of greater sensitivity than were used in the initial
survey detect radioactivity above the natural background threshold in previously
released material (USNRC, 2001b).
For surface-contaminated SRSM possessed by a materials licensee, the
USNRC usually authorizes its release through specific license conditions or tech-
nical specifications (USNRC,2001b). In the case of volume-contaminated SRSM
held by reactor and materials licensees, the USNRC has not provided guidance
similar to that found in Regulatory Guide 1.86 for surface contamination. These
situations are decided instead on an individual basis pursuant to Section 2002 of
10 CFR Part 20, typically by evaluating the doses likely to be associated with the
proposed disposition of the material. The case-by-case approach has some dis-
tinct advantages and disadvantages, as discussed in Chapter 2 and Chapter 9.
The Commission directed the USNRC staff in June 1998 to consider a
rulemaking for establishing a dose-based standard for release of SRSM (USNRC,
i6Chapter 2 discusses the AEA definitions of these materials.
i7Reactor licensees can apply to UNSRC for approval for clearance of solid materials with small
but detectable levels of radioactivity pursuant to section 2002 of lo CFR Part 20.
OCR for page 27
INTRODUCTION
27
1998a). The intent was to provide for consistent disposition of SRSM while
protecting public health and safety. The USNRC staff was also directed to ensure
that opportunities would be provided under the proposed standard for enhanced
public participation. The USNRC subsequently published an issues paper outlin-
ing possible courses of action were it to proceed with a rulemaking (64 Federal
Register 35090-35100; June 30, 1999~. As a first option, according to the issues
paper, the USNRC could restrict the release of SRSM only for certain authorized
uses or disposition options, in which the potential exposure to the public would
be small (conditional clearance). For example, restricting the options to disposal
of the SRSM in Resource Conservation and Recovery Act (RCRA) Subtitle D
landfillsl8 is a conditional clearance that would significantly reduce the number
of exposure pathways, relative to a situation in which the material is recycled into
consumer products. As a second option, the USNRC could permit the release of
solid materials for unrestricted use if the potential for exposure to the public from
projected uses were less than a specified dose level (clearance). Unrestricted use
might include recycle or reuse of SRSM in consumer or industrial products or any
other use. As a third option, the USNRC could prohibit both unrestricted and
restricted release of SRSM from a licensed facility. Instead, it could require that
such material go to an LLRW facility. For each of these alternatives, the impacts
on public health and the environment, as well as on cost-benefit factors, should
be considered. Consideration of the means of implementing each alternative and
its practicality would also be important if a rulemaking is undertaken.
The issues paper notes that consideration of rulemaking alternatives for solid
material release would cause the USNRC to examine the existing policies of
international bodies, other federal agencies, state governments, and other stan-
dard-setting bodies. The IAEA and the Commission of European Communities
have made significant efforts to set standards for the release of SRSM. These
bodies have adopted sets of standards based on an annual dose of 10 ,uSv/yr (1
mrem/yr), which is broadly accepted by the radiation protection community as a
de minimis dose.l9 Consistency among standards is an important concern be-
cause of the potential import or export of released materials between the United
States and other countries.
The issues paper further notes the importance of coordination with other
federal agencies, such as the EPA. In regulating its licensees, the USNRC imple-
18RCRA defines under separate subtitles the land disposal requirements for categories of waste at
different levels of potential health or environmental hazard. Subtitle D covers the lowest level of
potential hazard wastes equivalent to general municipal waste. Landfills meeting these require-
ments are called Subtitle D landfills. Similarly, landfills suitable for most common hazardous materi-
als generally used in or produced by industry are regulated under Subtitle C and are called Subtitle C
landfills.
19A de minimis dose is one at or below which statutory or regulatory controls would not apply. The
legal term "de minimis" is shorthand for de minimis non coral lex, which is Latin for the common law
doctrine stating, in free translation, that "the law does not concern itself with trifles."
OCR for page 28
28
THE DISPOSITION DILEMMA
meets the environmental standards set by the EPA. In the absence of EPA stan-
dards in areas such as the release of SRSM, the USNRC has the authority to set
standards. If proposed USNRC actions are not closely coordinated with the EPA,
problems could develop if the EPA later adopted conflicting standards. A major-
ity of the states have entered into agreements with the USNRC to assume regula-
tory authority over small quantities of byproducts, sources, and nuclear material.
Other standard-setting bodies such as the NCRP could play important roles in
setting dose standards for release of solid materials. The NCRP, a nonprofit
corporation chartered by the U.S. Congress, makes recommendations regarding
acceptable levels of radiation exposure to the general public, including levels
considered to present a de minimis health risk.
THE STUDY TASK AND APPROACH
The USNRC is considering whether to establish a new regulation that would
set specific limits for the release of solid materials with low levels of radioactiv-
ity (64 Federal Register 35090-35100; June 30, 1999~. The primary reason for a
new regulation would be to provide consistency in USNRC's regulatory frame-
work for releases of solid materials, including materials with volume contamina-
tion. Standards for the release of radioactively contaminated gaseous and liquid
materials have already been established.
The USNRC has sought public input in contemplation of such a rulemaking.
Two-day meetings were held in Chicago, San Francisco, Atlanta, and Rockville,
Maryland, in late 1999. Hundreds of written and electronic comments from the
public at large were received. Following the public meetings, the USNRC con-
tracted with the National Academy of Sciences to study several critical issues
related to the release of solid materials with low levels of radioactive contamina-
tion. The statement of work, which appears in excerpted form below, outlines
five tasks, to be performed by a committee appointed in accordance with the
procedures of the National Research Council (see Appendix C for the complete
statement of work):
1. As part of its data gathering and understanding the technical basis for the
Nuclear Regulatory Commission's (USNRC's) analyses of various alter-
natives for managing solid materials from USNRC-licensed facilities, the
committee shall review the technical bases and policies and precedents
derived therefrom set by the USNRC and other Federal agencies, by
States, other nations and international agencies, and other standard setting
bodies.
2. The committee will review public comments and reactions received so far
on current and former USNRC proposals to develop alternatives for con-
trol of solid materials. The committee will explicitly consider how to
address public perception of risks associated with the direct reuse, re-
OCR for page 29
INTRODUCTION
29
cycle, or disposal of solid materials released from USNRC-licensed fa-
cilities. The committee should provide recommendations for USNRC con-
sideration on how comments and concerns of stakeholders can be inte-
grated into an acceptable approach for proceeding to address the release
of solid materials.
3. The committee shall determine whether there are sufficient technical bases
to establish criteria for controlling the release of slightly contaminated
solid materials. This effort should include an evaluation of methods to
identify the critical groups, exposure pathways), assessment of individual
and collective dose, exposure scenarios, and the validation and verifica-
tion of exposure criteria for regulatory purposes (i.e., decision making
and compliance). As part of this determination, the committee should
judge whether there is adequate, affordable measurement technology for
USNRC-licensees to verify and demonstrate compliance with a release
criteria. What, if any, additional analyses or technical bases are needed
before release criteria can be established?
4. Based on its evaluation and its review, the committee shall recommend
whether USNRC (1) continue the current system of case-by-case deci-
sions on control of material using existing, revised, or new (to address
volumetrically contaminated materials) regulatory guidance, (2) establish
a national standard by rulemaking, to establish generic criteria for con-
trolling the release of solid materials, or (3) consider another alternative
approach~es).
If the committee recommends continuation of the current system of
case-by-case decisions, the committee shall provide recommendations on
if and how the current system of authorizing the release of solid materials
should be revised.
If the committee recommends that USNRC promulgate a national stan-
dard for the release of solid material, the committee shall: (1) recommend
an approach, (2) set the basis for release criteria (e.g., dose, activity, or
detectability-based), and (3) suggest a basis for establishing a numerical
limiters) with regard to the release criteria or, if it deems appropriate,
propose a numerical limit.
5. The committee shall make recommendations on how the USNRC might
consider international clearance (i.e., solid material release) standards in
its implementation of the recommended technical approach.
Limitations of the Study
In response to the USNRC request, the National Research Council estab-
lished the Committee on Alternatives for Controlling the Release of Solid Mate-
rials from Nuclear Regulatory Commission-Licensed Facilities (hereafter, the
OCR for page 30
30
THE DISPOSITION DILEMMA
TABLE 1-3 Risk Assessment Based on a Linear, No-Threshold Model with a
Probability of Developing a Fatal Cancer of 5 x 10-2 /Sv (5 x 10~/rem)
Hypothetical
Incremental Hypothetical Lifetime Risk
Incremental Dose Lifetime Risk (If dose received each year for 70 years)
1.0 mSv (100 mrem) 5 x 10-5 3.5 x 10-3
0.1 mSv (10 mrem) 5 x 10-6 3.5 x 10-4
0.01 mSv (1.0 mrem) 5 x 10-7 3.5 x 10-5
0.001 mSv (0.1 mrem) 5 x 10-8 3.5 x 10-6
"committee"~. In completing the five tasks listed above, the committee has worked
under several limitations and constraints that are worth noting at the outset. First,
for determination of the risk assessments on the health effects of incremental
doses, the committee has relied on assessments by UNSCEAR (1988), the Na-
tional Research Council Committee on the Biological Effects of Ionizing Radia-
tion (NRC, 1990) and the NCRP (1993~. These assessments found that a lifetime
risk20 of developing a fatal cancer from low dose or low dose rate irradiation is
estimated to be 5 x 10-2/Sv (5 x 10~/rem) for an individual in the general
population. Table 1-3 shows the risk estimates developed by NCRP (1993) by
applying the linear, no-threshold hypothesis to various incremental annual doses.
Second, the committee did not independently explore the relative validity of
various biological risk assessments associated with radiation dose. Such assess-
ments for low doses are controversial. They are subject to the assumptions made
according to the model employed. Independent evaluation of the validity of the
various risk assessments was beyond the scope of the task before the committee.
A third limitation was the exclusion of soils from major consideration. The
amount of soil involved in decommissioning the nuclear power plants is gener-
ally small relative to the quantities of concrete and metals as shown in Chapter 3
(Table 3-6~. On the other hand, the amount of contaminated soil at DOE facilities
can be significant.
Study Process
The committee organized three information-gathering meetings, at which
speakers were invited to make presentations before the committee on a range of
technical issues. Several stakeholder groups presented their views to the commit-
20Lifetime risk is the likelihood of an adverse health effect occurring (fatal cancer, in this instance)
at any time in the future due to exposure to radiation.
OCR for page 31
INTRODUCTION
31
tee. Views from industries affected by proposed clearance of SRSM were also
presented. Meetings in which information was presented to the committee were
open to the public, and when time permitted, either the speakers or members of
the committee addressed questions from the audience. Speakers were encouraged
to provide written statements or to provide the audience with copies of their
visual aids. Appendix B gives a detailed account of the speakers who provided
information to the committee at these meetings.
Certain members of the study committee visited two waste brokers, ATG in
Richland, Washington, and Duratek, Inc., in Oak Ridge, Tennessee. The mem-
bers observed and studied the methods currently used to release solid materials
with low concentrations of radioactive contamination from regulatory control.
Report Content
The regulatory framework for controlling the release of solid materials with
radioactive contamination is described in Chapter 2, which is organized into three
main sections. The first deals with the technical assumptions underlying radiation
standards and includes a review of the important concepts employed in establish-
ing radiation standards. The second section discusses the historical evolution of
regulatory practices and controls in greater technical detail than the introductory
account in this chapter. The third section provides a comparative assessment of
existing regulatory regimes in the United States.
Chapter 3 discusses the inventory of radioactively contaminated solid mate-
rials from USNRC licensees, DOE, DoD, and various industrial sources. The first
section of the chapter deals with waste streams from nuclear reactors. The second
section presents a much broader view of the accumulated inventory, including
licensed fuel cycle and non-fuel cycle facilities, DOE, DoD, EPA Superfund
sites, NORM, and TENORM.
Chapter 4 defines major alternatives for the disposition of solid materials
with low concentrations of radioactivity. A decision diagram with decision points
and disposition pathways is described. Estimated costs for various disposition
alternatives are discussed because disposal costs are markedly affected by the
disposal options available to a licensee for example, which disposal sites can be
used by a licensee for different categories of solid materials.
Chapter 5 reviews the technical basis for developing dose-based standards.
Implementing a dose-based standard requires a conversion from a concentration
of radioactivity in a solid matrix, as measured before release, to estimated doses
resulting from exposure of an individual in a critical group to that material. The
critical pathways and the assumptions made in performing these conversions are
discussed, as are the uncertainties in determining the factors for converting be-
tween measurable radioactivity levels and a dose standard.
Chapter 6 discusses the difficulties in quantitatively determining the identity
and activity of the radionuclides present in SRSM. It reviews the capability and
OCR for page 32
32
THE DISPOSITION DILEMMA
costs of instrumentation and measurement procedures to conduct the determina-
tion at various proposed screening levels. Also discussed are current measure-
ment practices of waste brokers and approaches to develop an appropriate sam-
pling program.
Chapter 7 reviews the efforts to develop international clearance standards.
The final section of the chapter summarizes the status of several countries in
establishing clearance standards for the release of SRSM.
Chapter 8 reviews stakeholder concerns and issues regarding past and recent
efforts of the USNRC to establish a clearance standard for SRSM. The chapter
emphasizes the importance of effective risk communication and establishing trust
in building stakeholder acceptance. Consensus-building processes to involve
stakeholders are presented.
Chapter 9 presents the committee's version of a decision framework for
considering alternatives for controlling the release of solid materials with radio-
active contamination. First, the problems with the current USNRC approach are
described. Then a systematic decision framework for considering the alternatives
for release of radioactive material is presented. The chapter also addresses issues
of public perception. A section on process considerations provides options for
obtaining enhanced participation from the public and possibly proceeding to a
rulemaking.
Chapter 10 contains key findings from the report that serve as a foundation
for the committee's recommendations. The committee's recommendations are
presented as well.
Representative terms from entire chapter:
radioactive materials
