Click for next page ( 14


The National Academies | 500 Fifth St. N.W. | Washington, D.C. 20001
Copyright © 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 13
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 13
INTRODUCTION 15

OCR for page 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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 13
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.