4
The Common Themes Approach
A conceptual framework to guide future discussions and disposition decisions about challenging low-level radioactive waste (LLW) streams1 was explored in the final session of the workshop. Case studies presented earlier in the workshop were discussed and “common themes” that led to successful disposition of previously challenging LLW streams were identified. Those themes were organized into a “common themes approach,” which was initially presented by John Applegate, planning committee chair. Workshop participants were then divided into five subgroups, each focused on applying the common themes approach to a challenging LLW stream:
- Greater-Than-Class C (GTCC) waste and transuranic (TRU) waste
- Incident waste
- Sealed sources
- Very Low-level and Very Low-Activity Waste
- Depleted uranium (DU)
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1 “Challenging LLW streams,” as used in these proceedings, are LLW streams that have potentially non-optimal or unclear disposition pathways due to their origin or content and incompatibility with existing standards, orders, or regulations. This is an imperfect definition as demonstrated by several of the waste streams in the list on this page. For example, many sealed sources do have disposition pathways—this workshop focused on the waste streams that are difficult to dispose of. For example, very low-level waste streams can be disposed of in existing disposal facilities, but the level of protection is not commensurate with the hazard and is therefore not optimal.
These wastes are described later in this chapter and in Appendix D. The subgroups came together at the end of the session to report their results, and the common themes approach was updated during the final discussion.
4.1 THE COMMON THEMES APPROACH
Mr. Applegate opened the session by restating the purpose of the workshop: to identify key characteristics of LLW that govern its management and disposal and to explore how those characteristics are used within existing regulatory frameworks. The workshop planning committee was not charged with inventing a new regulatory framework for LLW. Rather, the workshop used case studies to highlight successful examples of LLW management and disposal within existing regulatory frameworks.
Common themes within the case studies that led to successful disposition of the wastes were identified such as: the use of existing regulations and standards—such as the U.S. Nuclear Regulatory Commission’s (USNRC’s) Class A, B, and C classification scheme—to provide an anchor for disposal decisions; the identification of lessons learned from similar or analogous approaches such as Canada’s or France’s approach to managing and disposing of very LLW; and acknowledgement that the disposal site characteristics are as important for safe disposal as the inherent characteristics of the waste. These common themes were organized into a common themes approach that could be used within the current LLW regulations as an aid to guide decisions and direct discussions. The approach has three key elements: anchors, analogies, and adjustments:2
- Anchors: The current regulatory framework that governs LLW disposal provides a starting point for decisions about the disposition of challenging LLW streams.
- Analogies: Learn from successful disposition of similar wastes. Examples of past decisions for successful disposition of challenging LLW streams offer additional guidance for future waste disposal decisions.
- Adjustments: Use flexibility within current regulatory frameworks for making decisions about disposing of challenging LLW streams.
Existing U.S. regulations, as well as regulations and standards from international organizations, offer valuable guidance for making decisions
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2 Current USNRC regulations and the Department of Energy (DOE) policies allow for additional analyses and variances to accommodate a variety of waste characteristics. The approach described above and in Figures 4-1 and 4-3 is intended as a clarifying tool, not as a new concept.
about dispositioning challenging LLW streams. One need not write on a blank slate when making such decisions.
The common themes approach also makes use of the roughly proportional relationship between the hazard of a LLW stream and the required protectiveness of the facility that will be used for its disposal. This graphical representation could aid in discussions on identifying the levels of protection for a given level of hazard. This relationship is illustrated conceptually in Figure 4-1. The inherent hazard of the waste stream is represented on the x-axis of Figure 4-1. These hazards arise from the physical, chemical, and radiological properties of the waste stream (e.g., radiation types, activities, half-lives, and chemical toxicity).
The protectiveness of the disposal system is represented on the y-axis of Figure 4-1. The protectiveness characteristics include disposal depth, length of protection, and the number and types of barriers. Barriers can be
engineered (e.g., the waste form, engineered caps to retard water infiltration into the facility) and natural (e.g., impermeable formations underlying a disposal facility that retard waste migration). Physical security barriers (i.e., guns, gates, and guards) can also be considered if a waste stream poses a security hazard.
The solid line in Figure 4-1 is intended to be a conceptual representation of the proportional relationship between waste hazard and required disposal facility protectiveness. Class A, B, and C wastes (shown in shaded circles in Figure 4-1) have, respectively, increasingly higher levels of hazard and therefore need to be disposed of in facilities having increasingly higher levels of protectiveness. Challenging LLW streams can also be plotted on the conceptual line based on their hazards and needed levels of disposal facility protectiveness.
This type of graphical representation could help guide disposition decisions for wastes without clear or potentially non-optimal disposition pathways and could also help explain disposal decisions to non-experts. This representation is risk informed—a concept advocated by reports from the National Academies and others (National Research Council 1997, 2000, 2001, 2005, 2006b, 2011a, and Omnibus, 2015)—and is relatively easy to comprehend because it uses a small number of readily understood characteristics and shows the relationship between hazard and protection measures. This representation can also help to improve decision-making consistency for challenging LLW streams.
Mr. Applegate noted that there are not an infinite number of unknown LLW streams. Most LLW streams have been identified after many decades of nuclear activities. The waste streams that have been identified are amenable to treatment using the conceptual representation in Figure 4-1.
Planning committee member Nina Rosenberg noted that the barriers in Figure 4-1 are both natural (e.g., site characteristics) and engineered (e.g., waste forms or facility covers). Committee member Larry Camper provided guidance to the subgroups in applying the framework during the breakout session: when determining where each challenging LLW stream falls on the line in Figure 4-1, consider how that location translates to protection criteria.
4.2 DISCUSSION: THE COMMON THEMES APPROACH
Mr. Applegate asked participants for comments, criticisms, changes, or refinements to the proposed common themes approach. Lisa Edwards, senior program manager at the Electric Power Research Institute (EPRI), wondered whether the list of challenging LLW streams developed by the committee was consistent with the wastes that Department of Energy (DOE) is facing. Is very low-activity waste (or “very low-level waste” [VLLW] as
previously described by Gérald Ouzounian, international director for ANDRA3) a big challenge for DOE, more so than for the commercial sector? Are there other volumetrically large waste streams that have not been identified for discussion in this workshop?
Doug Tonkay, director of waste disposal at DOE, stated that the list appeared to be representative of both DOE’s and the USNRC’s challenging waste streams. He also stated that VLLW is important to DOE because of its large volume and consumption of available disposal space. The goal for DOE is to find the best deal for the taxpayer for the safe disposal of waste.
Communications
Mr. Tonkay recalled the Session 2 discussions on communications, noting that it is very important for DOE to improve communications with its stakeholders. The tool proposed in Figure 4-1 could help. DOE has expanded communication with the state of Nevada over the past couple of years, meeting quarterly to share information about waste that is anticipated for disposal at the Nevada Nuclear Security Site (NNSS). DOE has also augmented the technical information provided in the waste profiles for potentially challenging LLW streams such as sealed sources; for example, describing how the wastes that need to be disposed of have benefitted society. Mr. Tonkay stressed that he sees communications as a key component of any future approach to guide decision making. LLW has been defined by a patchwork of laws and regulations, resulting in a wide variety of waste streams. Clear decision frameworks are needed to explain how disposal decisions are made to address the wide range of characteristics of the wastes.
Other participants also stressed the importance of communication and suggested that it be a third axis in Figure 4-1. Daniel Goode, research hydrologist at the U.S. Geologic Survey (USGS), commented on the importance for the public to understand the benefits derived from the activities that produced the waste and noted that value judgments and popular opinions within populations evolve over time.
Shape of the Line in Figure 4-1
Several participants questioned whether the shape of the line in Figure 4-1 was linear or nonlinear. Participants noted that if the curve was nonlinear, then extrapolations at its ends—where the challenging LLW streams would fall—would be difficult. Further, Class A, B, and C wastes might better be described by horizontal bars in Figure 4-1 rather than dis-
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3 ANDRA is the French acronym for National Radioactive Waste Management Agency.
crete points. One of the planning committee members noted that the figure is conceptual and intended to convey the message that the need for disposal system protectiveness increases as waste hazard increases. The common themes approach and the figure are helpful for explaining management and disposal decisions on challenging LLW streams.
Commercial Disposal Costs
Participants with commercial disposal experience noted that the costs for disposal will affect disposal decisions, particularly when there is more than one disposal option. For example, Class B waste is usually co-disposed with Class C waste, but Class B waste could potentially be disposed of separately to reduce costs. Disposal costs are a nontechnical constraint (similar to communication) that is not directly captured in Figure 4-1.
Dr. Ouzounian noted that France’s approach to managing and disposing of radioactive wastes is consistent with the common themes approach and sliding scale illustrated in Figure 4-1. France has separate facilities for disposal of VLLW and LLW. The site itself is considered protective enough for disposal of VLLW—no additional barriers or protections need to be added. This leads to the factor of 15 to 18 cost savings for disposal as discussed previously in the workshop. In contrast, the protectiveness of both the waste form and the site are considered for the disposal of LLW.
Compatibility with Performance Assessment
A participant noted that the proposed common themes approach might lead to confusion or questions about the legitimacy of using performance assessment to guide decisions. A planning committee member commented that the proposed approach is meant to also guide decision making and could be used in conjunction with (and help with the communications related to) performance assessment.
Use of Chemical Toxicity in Figure 4-1
There were several questions from workshop participants about chemical toxicity and how this characteristic might be represented in Figure 4-1. Dr. Crowley noted that toxicity is a function of oxidation state, for example, and is mutable. The committee agreed that toxicity was not useful as a key characteristic and agreed to remove it from the key characteristics list in Figure 4-1. However, another participant suggested that waste mobility be added instead.
4.3 CHALLENGING LOW-LEVEL WASTE STREAMS
Mr. Applegate moderated the session on challenging LLW streams that would be discussed by the subgroups: GTCC and TRU, sealed sources, very low-activity waste, incident waste, and DU. These waste streams were described by experts from each of the subgroups in plenary session.
Lawrence “Rick” Jacobi, Jr., president of Jacobi Consulting, introduced GTCC and TRU wastes. Tameka Taplin, federal program manager in the National Nuclear Security Administration (NNSA4), introduced sealed sources. Lisa Edwards, senior program manager for EPRI, discussed very low-activity waste. William “Will” Nichols, principal environmental engineer at INTERA, provided an introduction to incident waste. Scott Kirk, director of regulatory affairs at BWXT, introduced depleted uranium and its disposal challenges. The biographies for these experts can be found in Appendix E.
GTCC and Commercial TRU Waste Greater than 100 nCi/g
Mr. Jacobi’s overview focused mainly on technical challenges for disposing of GTCC and TRU waste. The USNRC defines GTCC waste as waste that is generally not acceptable for near-surface disposal (within 30 meters of the surface). Its waste forms and disposal methods must be more stringent than those for Class C waste. DOE has “GTCC-like” waste,5 which is waste that is generated and owned by DOE and includes non-defense TRU waste. This GTCC-like waste has characteristics similar to commercial GTCC waste that is regulated by the USNRC. In 2015, USNRC staff recommended to the Commissioners to allow the state of Texas to license the disposal of GTCC waste (USNRC, 2015c).
TRU waste is defined in the WIPP Land Withdrawal Act as waste containing alpha-emitting transuranic nuclides (transuranic nuclides are elements with an atomic number greater than 92 in the periodic table) at concentrations greater than 100 nanocuries per gram (nCi/g) and with half-lives greater than 20 years.
In January 2016, DOE estimated the volume and activity of GTCC and GTCC-like waste in the United States to be about 12,000 cubic meters and 160 million curies, respectively. This is not a volumetrically large waste stream, but it contains a lot of radioactivity. Most of the waste is activated
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4 The NNSA is a semi-autonomous agency within DOE.
5 GTCC-like waste is a descriptive term DOE adopted for purposes of the Environmental Impact Statement (EIS) for GTCC and GTCC-like waste. It is not a formal waste class within DOE order or U.S. regulation. This descriptive category includes both higher activity DOE LLWs and non-defense TRU wastes that do not currently have disposal pathways and that have characteristics similar to or meet the regulatory definition of GTCC LLW as defined in the 10 CFR 61 tables.
metals from the planned decommissioning of nuclear power reactors. This waste also includes sealed sources, sludge, resin, and contaminated soil. Mr. Jacobi noted that this waste inventory does not include a large number of sealed sources used by the oil and gas industries.
The DOE’s final environmental impact statement (EIS) for GTCC and GTCC-like waste (DOE, 2016) proposed several disposal options for GTCC, GTCC-like, and commercial TRU waste, which include:
- A deep geologic repository, such as WIPP.
- A near-surface trench with engineered barriers.
- Above-grade vaults.
- Intermediate-depth boreholes.
Intermediate-depth (more than 30 meters below the surface) disposal is also discussed in the International Atomic Energy Agency General Safety Guide (IAEA, 2009a). Mr. Jacobi suggested that intermediate-depth disposal is an appropriate option and that a better name for GTCC waste might be “intermediate-depth waste.”
Several participants mentioned the progressive improvement of disposal facilities over the past several decades. Early disposal practices were relatively primitive, waste forms were deficient, and performance assessment modeling was rudimentary. Waste was stored in boxes, drums, and sacks, which were dumped into trenches and covered with dirt. Modern-day disposal facilities are engineered to minimize waste. Operational practices are improved, and waste forms are more robust. Modeling capabilities and techniques are also much better.
As an example, the WCS facility in Andrews, Texas, is the United States’ newest LLW disposal facility. The facility is located in an arid environment with low rainfall and a deep groundwater table; the site has low seismicity; the facility is underlain by a low-permeability clay; and the region surrounding the facility has a low population density. Additional engineered barriers have been added to the disposal facility, including compacted clay, concrete sidewalls, geo-synthetic liners, and intrusion barriers. The waste is disposed of in concrete canisters with limitations on void space in the waste as well as waste stability requirements.
Mr. Jacobi proposed that the type of reanalysis required under the USNRC’s Branch Technical Position on Concentration Averaging and Encapsulation (BTP)6 (see Chapter 2) would likely result in the reclassification of some portion of GTCC to Class C waste. The remaining GTCC (and possibly TRU waste) could be disposed of in a facility comparable to the
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6 “USNRC: Branch Technical Position on Concentration Averaging and Encapsulation,” accessed February 26, 2017, https://www.nrc.gov/waste/llw-disposal/llw-pa/llw-btp.html.
WCS. He recommended that the United States should consider replacing “GTCC” nomenclature with “intermediate waste” following IAEA safety guidance (he noted that the rest of the world is using this nomenclature). He also recommended that future GTCC waste streams need to be considered and planned for—GTCC from Gen IV reactors is a good example. Finally, he recommended that performance assessments used to develop the USNRC waste classification system should be conducted with modern computer codes, newer standards, and data from modern LLW disposal facilities.
Sealed Sources
A sealed source is “[a] radioactive source in which the radioactive material is (a) permanently sealed in a capsule or (b) closely bounded and in a solid form” (IAEA, 2014, p. 423). There are thousands of sealed sources in use and in storage in the United States and around the world. Ms. Taplin explained that her role within the NNSA Off-Site Source Recovery Program (OSRP)7 is to collect disused sealed sources from domestic and international locations and store and dispose of them in the United States. As mentioned previously by Mr. Tonkay, DOE provides information about the beneficial uses of sealed sources to stakeholders so that these societal benefits are considered in making disposal decisions.
Sealed sources can be highly radioactive (e.g., tens to hundreds of thousands of curies for radiotherapy or radioisotope thermoelectric generators [RTGs]), so proper packaging and transportation is a very important part of managing their disposal. Sealed sources normally have adequate documentation about their manufacture and use; this documentation is useful for planning for the disposal of these sources.
As an example of a challenge for the program, Ms. Taplin noted that occasionally the transportation certification for the packaging of a sealed source is found to be expired. This adds some complication to the recovery and for communication (i.e., the description of the process to others). DOE engages and communicates with communities along the planned transportation routes for these sources, including information about the beneficial uses of these sources.
Exempt and Very Low-Activity Waste
Ms. Edwards framed her presentation in the context of VLLW and very low-activity waste instead of clearance or exempt waste. She suggested a rough definition of VLLW as waste containing less than or equal to 10 per-
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7 OSRP’s broader mission is to remove excess, unwanted, abandoned, and orphan radioactive sealed sources that pose a potential risk to national security, health, and safety.
cent of the Class A waste activity limits. She admitted that this was not a technically refined definition, but that it was a good-enough definition for the purposes of the workshop.
VLLW is a large-volume, low-activity waste stream with a low intrinsic hazard compared to other LLW streams, even most Class A waste streams. It falls on the lower part of the notional line on Figure 4-1 represented by the lower orange circle. VLLW is recognized in the IAEA radioactive waste classification scheme and in other countries as a formal waste classification. Dr. Ouzounian described how this waste classification has been successfully employed in France. Spain and other countries also use this waste classification.
One question to be discussed during the breakout session is whether the United States needs to develop a formal regulatory definition for VLLW. The USNRC exemption process (i.e., the 20.2002 exemption) is currently used to manage some VLLW streams. The exemption process allows lower-hazard waste to be disposed of in less-protective (but still adequately protective) disposal facilities than higher-hazard waste. However, the exemption process lacks transparency and can make it difficult to communicate with the public about waste-disposal decisions. The industry has asked the USNRC to publish the requirements it uses for making 20.2002 exemption decisions in a publicly available guidance document.
Some Agreement States have issued licenses to disposal facilities to accept certain VLLW streams. For example, some VLLW is approved for disposal in Resource Conservation and Recovery Act (RCRA) facilities.
Ms. Edwards argued that it would be preferable for the United States to develop a formal regulatory definition for VLLW (or very low-activity waste) that could be used to guide its disposal, rather than relying on the current exemption process. The regulatory definition would identify the key characteristics of this waste that could be used to determine its hazard for the purposes of selecting an appropriate disposal method. Having a formal regulatory definition would have a large economic impact. Ms. Edwards estimated that impact would be about $6 billion in cost savings for disposing of decommissioning wastes from U.S. nuclear plants (see Figure 2-3 in Chapter 2)—a cost savings that some have argued is a gross underestimation. The diversion of VLLW to other disposal facilities would free up capacity in LLW disposal facilities to dispose of higher-hazard waste. VLLW is expected to consume a large portion of currently available LLW disposal capacity in the United States, perhaps far into the future.
Incident Waste
For the purposes of this workshop, “incident waste” is defined as radioactive waste that would be generated from a nuclear accident or
nuclear/radiological terrorist attack, collectively referred to here as a nuclear/radiological emergency. Mr. Nichols recently participated in an IAEA consultancy that developed a technical guidance document on the management of large volumes of radioactive waste that would result from a nuclear/radiological emergency.8 He provided highlights from the draft IAEA guidance document to scope the workshop’s breakout discussions on incident waste.
Much can be learned about incident waste from previous nuclear/radiological. The most important examples are the Chernobyl and Fukushima accidents, but less well-known examples can also provide important insights. For example, the 1987 Goiânia accident in Brazil resulted in extensive environmental contamination after a teletheraphy source was removed from its protective housing in a device that was left behind in an abandoned clinic. The breached source contaminated several people and sites. The Chernobyl and Fukushima nuclear accidents further highlight the need for planning for the management of large quantities of incident wastes that would be very suddenly generated following such emergencies.
The nature, scale, and timing of nuclear/radiological emergencies cannot be predicted. However, one can plan for the impacts of such emergencies, including health and safety, environmental, societal, and financial impacts. A large-scale emergency would place instant demands on national resources and present key challenges for managing incident wastes. These include characterizing and managing the waste during the emergency response and responding to public concerns about those wastes. Mr. Nichols noted that the decision making and regulatory frameworks were severely strained in the nuclear/radiological emergencies studied during the IAEA consultancy, particularly when there was no pre-planning or regulatory framework to cope with incident wastes.
Key challenges for managing incident waste are the need for (1) rapid characterization to assess its hazard and (2) waste segregation by those characterized hazard levels. Incident waste must be segregated by hazard level to be managed effectively. Otherwise, all of the waste must be managed to the highest hazard level of any of its components. Mr. Nichols suggested that proposed regulatory framework illustrated in Figure 4-1 was a good way to quickly and clearly segregate incident wastes.
Incident waste management is unlikely to get much attention in the initial stages of a nuclear/radiological emergency. But early decisions and actions could potentially have long-term, unintended consequences for waste management and disposal if not considered in planning and preparation for such emergencies.
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8 This guidance report has not yet been released.
Depleted Uranium
DU is depleted in the isotope uranium-235 relative to uranium-238. It is produced during the uranium enrichment process. Mr. Kirk provided background and history on the DU waste stream in the United States. In 1982, the USNRC promulgated 10 CFR 61, which defined uranium-containing waste as Class A waste. The analysis supporting the rulemaking considered typical or expected waste streams that were in existence at that time, such as small quantities of DU from commercial generators. In 2003, Louisiana Energy Services (now URENCO USA) proposed construction of a national uranium enrichment facility near Eunice, New Mexico, which would produce much larger quantities of DU than previous generators. DU had been determined to be more hazardous than previously thought when this enrichment facility was proposed. The USNRC commissioners directed agency staff to determine whether DU could be safely disposed of in a near-surface (i.e., within 30 meters of the surface) disposal facility. The commissioners later directed agency staff to begin a rulemaking to develop requirements that would be site specific and could be used to demonstrate that disposal of large quantities of DU could be done safely (USNRC, 2008). The final rulemaking is expected to be sent to the USNRC commissioners in the near future.
The USNRC also developed guidance for Agreement States to process requests for disposal of DU received prior to the completion of the rulemaking. This guidance suggested that disposal of DU may be appropriate in a near-surface disposal facility under certain conditions, such as when robust engineered barriers were used and/or the uranium was disposed of at greater depths.9
Mr. Kirk explained why DU is more hazardous than previously thought. Figure 4-2 shows the activity ratio (i.e., the activity at the waste at some future time divided by its initial activity) for typical LLW streams (solid blue line in Figure 4-2). The activity of the typical LLW stream decays to 1/100th of its original value after approximately 1,000 years. The activity ratio for DU increases almost tenfold due to ingrowth of daughter products (dotted blue line in Figure 4-2).10 Therefore, the risk to public health and safety for disposal of depleted uranium is substantially different from other types of LLW.
The USNRC’s analyses show that disposal of DU in facilities located at arid sites is adequate to protect public health and safety if the DU is
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9 This guidance has been used by Waste Control Specialists, LLC (WCS) to amend its license to allow for DU disposal at increased burial depths (i.e., 100 feet). “License Amendment Enhances Disposal Options,” August 28, 2014, http://www.wcstexas.com/2014/license-amendment-enhances-disposal-options/.
10 The decay of uranium-235 and uranium-238 produces a number of radioactive daughter products that slowly build up (or grow into) the DU, increasing its activity ratio.
NOTE: Activity ratio is the activity of the DU at some future time divided by its initial activity. LLW = low-level waste.
SOURCE: Courtesy of James Scott Kirk, BWXT.
disposed of at appropriate depths using appropriate engineered barriers. The USNRC’s proposed rule for disposal of DU suggests three tiers of protection: a 1,000-year period of compliance, 1,000-to 10,000-year assessment period, and greater-than-10,000-ear period of performance. The rule requires performance assessments to demonstrate less than 25 millirem per year (mrem/yr) (less than 0.25 milliseivert per year [mSv/yr]) exposure, an intruder analysis to show less than 500 mrem/yr (5 mSv/yr), and an analysis to show site stability.
Mr. Kirk used the WCS license application for disposing of DU to highlight examples of natural and engineered barriers. The site characteristics in the application included red clay beds (nearly as impermeable as concrete and 600 to 800 feet [180-240 meters] in thickness), the water table (about 600 to 1,000 feet [183-305 meters] below grade), and annual rainfall (approximately 15 inches [38 centimeters]) per year, with a potential evapotranspiration of about 60 inches [150 centimeters] per year). The only expected exposure pathway after disposal is through intrusion. Engineered barriers include a cover system (about 33 feet [10 meters] in thickness to retard migration of radon) and a reinforced concrete barrier surrounding the disposal site. The Texas regulator mandated that WCS dispose of DU at the deepest depth possible—which is about 120 feet (37 meters) below grade.
4.4 SUMMARIES FROM BREAKOUT SESSIONS
The discussion of breakout session summaries was moderated by Mr. Applegate. He first presented an update to and further explanation of the common themes approach in response to the earlier discussion. To recapitulate, the common themes approach consists of three steps:
- Consideration of four elements: anchors, analogies, adjustments, and anticipation, the latter element added after the earlier discussion,
- Use of an updated sliding scales graph (Figure 4-3) to connect the hazard of the waste to protectiveness of the disposal system, and
- And a new step: Review of “further dimensions,” which are not included in the sliding scales graph of Figure 4-3, such as communication.
“Anticipation” was added to the original three key elements (i.e., anchors, analogies, and adjustments) in recognition that surprises can be avoided through anticipation of future waste streams. The dotted lines in
the updated graph (Figure 4-3) reflect the flexibility of current LLW regulatory frameworks. Note that chemical toxicity was dropped from the x-axis of the figure, and the y-axis includes both inherent site characteristics and engineered barriers for site protections.
The y-axis label was also updated to reflect the fact that the protectiveness of the disposal facility can be adjusted (“tuned”) to match the waste hazard. In other words, the solid line in the graph becomes a sliding scale that can adjust waste hazard to disposal facility protectiveness.
The “further dimensions” are not shown on the updated figure. Nevertheless, they need to be considered when making disposal decisions. Such dimensions can include chemical hazards, sustainability, the beneficial activities that generated the waste (i.e., waste source), and political and public concerns.
Experts from each subgroup summarized the subgroup’s discussions on applying the common themes approach to the previously identified challenging LLW streams. Subgroup members offered additional comments and identified actions that could lead to finding management and disposal decisions for challenging LLW streams.
Subgroup 1: GTCC/TRU
Mr. Jacobi summarized the discussion of the GTCC/TRU subgroup. The subgroup recognized that the USNRC, state of Texas, and WCS are currently involved in the ongoing 10 CFR Part 61 rulemaking for GTCC/TRU wastes and that each of these entities has a different perspective and approach to the problem. The USNRC’s approach to updating Part 61 is to be generic in identifying characteristics and criteria, because the agency cannot create regulations with specific disposal sites in mind. However, a likely site for the GTCC/TRU wastes is WCS in Texas, which does have specific characteristics—both inherent and engineered—that make it potentially suitable for disposal of these wastes.
The subgroup concluded that Part 61 should strive to have specific technical criteria that form a baseline for analysis (i.e., the “anchor” in the common themes approach), but also that Part 61 needs to be as generic as possible—an admitted paradox. Once a site is selected, the “generic technical criteria” can be converted to site-specific technical criteria in a formal performance assessment. This would be the “adjustments” element of the common themes approach.
Several “further dimensions” were identified during the subgroup discussions. Communications and engagement with the public need to be part of the approach. Institutional challenges must not be overlooked, either. Charles Maguire, director of the Radioactive Materials Division within the Texas Commission on Environmental Quality, explained that the jurisdiction for
GTCC waste decisions in Texas has not yet been clarified by the USNRC. Until that happens, GTCC, GTCC-like, and/or TRU waste cannot be accepted at WCS.
There was a short clarifying discussion about the origin of the classification that specified the TRU waste 100 nCi/g activity level between Class C and GTCC waste. A lower threshold established in the early 1980s (10 nCi/g) was increased to the current value (100 nCi/g) because the lower value was difficult to measure and verify with then-existing survey equipment. Additionally, a “fudge factor” was added so that the application of the new threshold would result in very limited amounts of GTCC or TRU waste above the Class C threshold, or so it was thought at that time.
Mr. Kirk noted that it was recognized early on that a repository would suffice for GTCC and TRU disposal, but exceptions (described below) were provided so that a percentage of lower-hazard GTCC and TRU waste could be disposed of in a Part 61-like (i.e., near-surface) facility. Specifically, the Land Withdrawal Act for the Waste Isolation Pilot Plant defined TRU waste as waste containing transuranic elements that exceeded 100 nCi/g with a half-life longer than 20 years. But the Act provided three exceptions [WIPP, 1996, pp. 1-2]:
- High-level radioactive waste;
- Waste that the Secretary [of Energy] has determined, with the concurrence of the [Environmental Protection Agency] Administrator, does not need the degree of isolation required by the disposal regulations; or
- Waste that the [US] Nuclear Regulatory Commission has approved for disposal on a case-by-case basis in accordance with Part 61 of Title 10, Code of Federal Regulations.
Some participants pointed to the increasing complexity of the regulations as problematic for disposing of these wastes. There should be a calculation of the risk of “doing nothing” when updating or creating regulations, especially when the volumes of the wastes are significant. A few participants noted that there is no immediate pressure from nuclear power plants to dispose of their commercial GTCC wastes, but DOE is pursuing the disposal of these wastes. Regardless, the USNRC rulemaking needs to move forward because the commercially stored wastes will eventually need to be disposed of.
Mr. Camper and Theresa Klickzewski, DOE, identified the following near-term next steps. Mr. Camper’s suggestion was to provide comments on the GTCC rulemaking when requested by USNRC staff through Federal Register notices or public meetings. He made a similar suggestion for the expected (in the next year or so) rulemaking for TRU waste.
Ms. Klickzewski provided a few suggestions related to DOE’s next actions. A DOE report required by the Energy Policy Act of 2005 (EPAct of 2005)11 on GTCC disposal options will soon be delivered to Congress. The Act requires DOE to await Congressional action, but it does not specify what form that action will take. DOE and Congress have agreed to hold a meeting to determine how Congress will provide its recommendations to DOE (e.g., by letter, verbally). After the recommendation is received from Congress, DOE will be able to issue a record of decision (ROD) that defines the acceptable disposal pathway(s).
Another “next step” that DOE will take in parallel is to continue to work with the USNRC as part of the 10 CFR Part 61 update process. DOE will need to receive USNRC’s technical criteria for GTCC to be able to dispose of its GTCC waste.
Subgroup 2: Sealed Sources
Ms. Taplin provided a brief summary of the sealed sources subgroup discussions. Sealed sources are distinct from the other types of wastes discussed today. Sealed sources come in a variety of shapes, sizes, and activity levels. Those that contain very high-activity sources, for example sources used in irradiators, are usually doubly encapsulated and stored in heavily shielded containers. These containers can weigh thousands of pounds. The risks of radioactive material leakage from these very large sealed sources during normal handling and use is nearly nonexistent, and scenarios to calculate exposure risks are restricted to individuals with malicious intent.
An example of a challenging sealed sources waste stream is high-activity cesium sources that contain greater than 130 curies of cesium-137. This waste stream is challenging because it requires additional analysis before a disposition can be made. The upcoming USNRC Branch Technical Position on Concentration Averaging and Encapsulation (BTP) for Class A, B, and C waste may affect how these types of sealed sources are managed and disposed of. The determination of final disposition for this type of sealed
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11 DOE has a statutory responsibility from the LLWPA amendment to site a GTCC LLW disposal facility and explicit direction to proceed with the EIS from the Energy Policy Act of 2005 (EPAct). From the EPAct, Sec. 631: “(B) ANALYSIS OF ALTERNATIVES.—Before the Secretary [of Energy] makes a final decision on the disposal alternative or alternatives to be implemented, the Secretary shall—
(i) submit to Congress a report that describes all alternatives under consideration, including all information required in the comprehensive report making recommendations for ensuring the safe disposal of all greater-than-Class C low-level radioactive waste that was submitted by the Secretary to Congress in February 1987; and
(ii) await action by Congress.”
For more details, see “Energy Policy Act of 2005,” accessed April 9, 2017, https://www.gpo.gov/fdsys/pkg/PLAW-109publ58/pdf/PLAW-109publ58.pdf.
source would be a good test of the common themes approach presented by Mr. Applegate. In fact, Figure 4-3 was used by the subgroup as a way to discuss risk reduction for a potential malicious intruder by increasing the disposal depth (but no specific depths were suggested).
Subgroup participants noted that site-specific characteristics and protections will ultimately determine whether disposal is allowable for a given type of sealed source. The subgroup agreed with the GTCC subgroup that specific technical criteria that form a baseline for analysis should be as generic as possible. For example, sealed source waste generators—hospitals, for example—would welcome an approach that did not require detailed, site-specific technical analysis for every disposal decision. If the regulations become too unwieldy for waste generators, the likelihood of the sealed sources remaining on site in storage increases, which also increases the potential risk that the sources could be stolen or weaponized in place.
Ms. Taplin and David Martin, a contractor for the NNSA, suggested a next step by the USNRC would be clear implementation guidance on the Branch Technical Position mentioned previously. It provides guidance on what can be disposed of at USNRC-regulated facilities. Sources that have activities above certain thresholds (e.g., 130 curies for cesium) require additional special analysis for disposition.
Mr. Martin noted that challenging sealed source waste streams are limited in number and identifiable (the “anticipation” step outlined in the updated common themes approach). He suggested the creation of a forum to review these challenging source waste streams and to identify what additional protections, such as inherent site characteristics, depth of disposal, and/or engineered barriers (i.e., the y-axis of Figure 4-3) would be necessary to allow these sources to be disposed of in near-surface facilities. Waste generators could use the information generated by the forum to guide disposal of these sources. Mr. Applegate suggested that disposal pathways for these sources could be explicitly identified by the forum.
Subgroup 3: Clearance or Very Low-Activity Waste
Ms. Edwards explained that this subgroup’s discussion focused on very low-activity waste (i.e., VLLW) and the current approaches to disposing of it, including an exemption process within current USNRC regulations (i.e., the 20.2002 exemption discussed in Chapter 2). The subgroup did not discuss clearance or exempt waste.12
The 20.2002 exemption is currently used by many Agreement States and their licensed disposal facilities to dispose of large volumes of VLLW
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12 To clarify terms, “exempt waste” is not waste that has been subjected to the 20.2002 exemption process. Further, the 20.2002 exemption process does not reclassify the waste—it remains LLW.
in RCRA-like facilities. For example, WCS is currently authorized through this exemption process to dispose of LLW by means other than those defined in 10 CFR Part 61 as long as certain requirements are met, such as the waste streams have very low activities. The process grants an exemption to RCRA facilities to receive VLLW, subject to certain requirements by the state regulator.
Other organizations have different ways of managing VLLW. DOE, which is self-regulating, uses the “authorized limits process” to dispose of wastes with low levels of radioactivity at on-site disposal cells. France has a separate classification and disposal process for VLLW as discussed earlier in the workshop.
One could point to the 20.2002 exemption, or the authorized limits process, as “anchors” for VLLW. Alternatively, the French classification system could be used as an “anchor” or “analogy” should the United States decide to add a classification level for VLLW. In fact, Ms. Edwards noted that the subgroup supported the idea of adding a new classification category for this waste type.
The subgroup thought it would be easier to describe VLLW disposal decisions to stakeholders and the public through a new classification than through the current exemption process, which is complicated, granted on a case-by-case basis, and lacks transparency. The terminology is also confusing: VLLW is reviewed through an exemption process for disposal at a RCRA facility, but the waste is not “exempt” waste. There is also the need to reserve space in LLW disposal sites for wastes that pose a higher hazard than VLLW as noted previously.
Dr. Goode suggested that an independent study be commissioned to review the current status and processes for disposing of VLLW. The study should identify the volumes and activities of VLLW in the United States and its possible disposal pathways. The study would provide a broad but thorough picture of the U.S. approach to the disposal of this waste and would inform the scientific community and the public.
Andrew Orrell, section head for waste and environmental safety at the IAEA, identified a slight tension between the interests of DOE and commercial parts of the disposal system, specifically with respect to the introduction of a new waste category versus anxiety by commercial facilities, for example, about changes to the current regulatory structure. He recommended the creation of a task force to help decide whether creating another waste category would actually result in cost savings for industry and enhance public understanding.
Subgroup 4: Incident Waste
Mr. Nichols summarized the subgroup’s discussion and attempted to link it directly to the common themes approach, outlined by Mr. Applegate at the start of the session. What are the characteristics of the anticipated waste? Incident waste is highly heterogeneous, including radioactively contaminated biological materials (e.g., plants, agricultural products, and animals), infrastructure (e.g., buildings, vehicles), liquids,13 and ion exchange resins used to remove contamination from liquids. The quantity of waste is potentially large, rapidly produced, and geographically distributed. Incident waste potentially covers the range of hazards in Figure 4-3.
The challenges for disposing of incident waste are many:
- Characterization and segregation of the waste will be challenging given its volume and distribution. Waste management will not be the highest priority during the initial response to a nuclear/radiological emergency, but early decisions on segregation could have long-term impacts on disposal options.
- Identifying the disposition endpoints (i.e., how clean is clean enough?) will require input from stakeholders and will help determine what areas are cleaned up and to what extent.
- Waste storage sites will need to be found or designated until the waste can be disposed of.
- The capacity of existing LLW disposal sites could easily be overwhelmed by a single large-scale nuclear/radiological emergency.
The subgroup identified preplanning as a critical component in addressing these challenges. The wastes would initially be characterized and segregated by activity level to manage the threat/hazard, but it should not be subject to waste classification at this initial stage. In fact, some in the subgroup thought that “incident waste” ought to be established as a separate waste classification and that performance assessment be used to guide its management.
Mr. Tonkay noted that the right of eminent domain should be added to the challenges for management of incident waste—or perhaps to the “further dimensions” step. Citizens’ property could become contaminated as a result of the event. Initially, it might be clear that property owners and citizens should evacuate, but preplanning could help to clarify when they can be allowed to return and how their contaminated property will be dispositioned.
Mr. Nichols suggested that a next step would be to consider creating a special category for incident waste, recognizing of course that such wastes
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13 For example, contaminated liquid wastes from building decontamination and waste removal activities.
would have to be managed using a risk-informed approach. Also, a regulatory analysis needs to be included in the emergency planning to determine how the classification might hinder or help recovery actions.
Dr. Crowley added a few comments. He noted that the Environmental Protection Agency (EPA) has done significant work on Protective Action Guidelines (PAGs), which at least provide a conceptual understanding of what to do from a protective standpoint. However, there is less understanding of how to deal with the waste itself. There have been a couple of unintentional experiments, the Chernobyl and Fukushima accidents. A next step, if not already done, would be to see how incident waste from those accidents was handled and what lessons could be learned. This information could be used to develop guidance for policy makers in the United States about how to respond to future nuclear/radiological emergencies. He also noted that incident waste is not likely to be a problem for DOE unless there was an accident at a DOE site. Rather, an accident/attack was more likely to occur in the civilian sector, for example a nuclear plant accident or a terrorist attack on a major city.
Mr. Orrell noted that the IAEA is almost ready to release two publications on incident waste: a safety guide and a technical document on preparing for and managing incident waste. Dr. Ouzounian noted that in France they have prepared and practiced a concept for managing waste from emergency situations, a concept that has been in place for a few years.
Subgroup 5: Depleted Uranium
Mr. Kirk noted that there is a well-known amount of DU and that work has focused on identifying the right waste form. Most DU is in the form of uranium hexafluoride (UF6)14 in cylinders. DOE recognized early on that UF6 would have to be converted into a more stable solid such as uranium oxide (e.g., U3O8) to make it suitable for disposal.
Mr. Kirk noted that the newly added dashed lines in Figure 4-3, representing the flexibility of existing regulatory frameworks, were also appropriate “anchors” for DU, which grows more radiotoxic (from Class A waste to higher classes) as daughter products grow in over time (Figure 4-2). Pathways for disposition of a significant amount of DU have already been determined—for example, DU has been disposed of at the EnergySolutions LLW disposal facilities at Hanford, Washington, and Barnwell, South Carolina. DU may also be appropriate for disposal at more modern LLW disposal facilities, for example the WCS facility in Andrews, Texas—subject to the completion of the final 10 CFR Part 61 rulemaking.
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14 At atmospheric temperature and pressure, UF6 is a solid. It will sublime into a gas at 134°F (57 °C) and ambient pressure.
Existing regulatory protection standards were discussed as “analogies” within the common themes approach. For example, the WCS license contains a general prohibition against disposal of large quantities of DU, but there was also an activity limit of 10 nCi/g—meaning that DU could be disposed of if its activity is less than 10 nCi/g.
The rulemaking poses some regulatory hazard to facilities that have already disposed of DU. It is possible that the rulemaking will require that additional protections be added at older facilities that have disposed of DU as Class A waste. (The rulemaking could affect other waste streams that have been disposed of as Class A waste.) Mr. Garmaszeghy noted that the wastes currently disposed of at disposal facilities are subject to changes in regulations. Daniel (Dan) Shrum, senior vice president of regulatory affairs at EnergySolutions, noted that facilities have to comply with changes in USNRC regulations, even for waste that has already been disposed of, on a case-by-case basis.15
Mr. Kirk suggested two steps that could be taken to advance the decision-making process for disposal of DU. The first is for DOE to complete its National Environmental Policy Act (NEPA) review16 and, second, for the USNRC to finish the 10 CFR Part 61 rulemaking. The NEPA review is a requirement before federally owned DU can be disposed of at commercial facilities. The facilities will need to review the updated Part 61 rulemaking to determine its meaning and impacts. Mr. Shrum noted that the EnergySolutions LLW Disposal Facility in Clive, Utah, is working on a DU performance assessment to amend its existing license to accept large quantities of DU. The assessment had been dropped to a lower priority, but there is renewed focus by EnergySolutions to finish the assessment so that the state regulator can evaluate it.
Mr. Camper commented that 10 CFR Part 61 is based on an EIS that was prepared at the time the regulation was created, but the EIS has never been updated. Facility design and operation assumptions that were used in the original EIS may be different from modern facility designs and operations. For example, the EIS did not envision disposal facilities like WCS in Texas or EnergySolutions in Clive, or even the changes to facility designs and operations that have occurred at the EnergySolutions LLW disposal facility in Barnwell, South Carolina. Also, the volumes and types of LLW
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15 See USNRC 10 CFR 61.1: “(a) … Applicability of the requirements in this part to Commission licenses for waste disposal facilities in effect on the effective date of this rule will be determined on a case-by-case basis and implemented through terms and conditions of the license or by orders issued by the Commission.” Accessed March 29, 2017, https://www.nrc.gov/reading-rm/doc-collections/cfr/part061/part061-0001.html.
16 “DEPARTMENT OF ENERGY Notice of Intent To Prepare a Supplemental Environmental Impact Statement for Disposition of Depleted Uranium Oxide Conversion Product Generated From DOE’s Inventory of Depleted Uranium Hexafluoride,” posted August 26, 2016, https://energy.gov/sites/prod/files/2016/08/f33/EIS-0360-S1-NOI.pdf.
being disposed of at these facilities are remarkably different from original assumptions. The USNRC should update the EIS to represent actual waste streams and disposal facility designs and operations. The existing EIS is difficult to amend, and a new EIS is expensive to develop. If a new EIS is not feasible, then an independent study or analysis could be carried out to more accurately capture modern LLW disposition practices. Such a study could be funded from DOE, USNRC, and possibly industry. The general public, as well as other countries, would also benefit from this analysis.
4.5 FINAL THOUGHTS: REVIEW OF THE COMMON THEMES APPROACH
Mr. Applegate asked the participants for final thoughts on using the decision framework (or, as he referred to it, the Common Themes approach). Ms. Klickzewski’s comment was that federal agencies should do something. They should take an action to show movement and progress. Whether it is the BTP from the USNRC, or a ROD from DOE on GTCC waste, or the NEPA for DU, action is needed. Mr. Applegate agreed with her comment. He was surprised at the activity that has already taken place for many of the waste streams and wondered why they are seen as “challenging” by DOE and the USNRC. He hypothesized that perhaps the final disposition decisions are actually close to being made—or closer than it was assumed when the workshop was requested by DOE.
Mark Yeager, division of waste management at South Carolina’s Department of Health and Environmental Control, noted that states deal with multiple regulatory regimes: DOE, the USNRC, and the EPA. He suggested that these three agencies come together to develop an integrated approach for regulation of LLW, perhaps using the Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) as a model. He stressed that until there is a consistent and complete regulatory framework across the regulatory agencies, it will continue to be difficult to gain confidence from the public. Ming Zhu, acting budget director for DOE’s Office of Environmental Management, agreed with the need for integration across agencies and noted that this was a key finding from a recent omnibus risk review,17
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17 The Consolidated Appropriations Act, 2014 (referred to as the “Omnibus”) (Omnibus, 2015, p. v) directed DOE to “retain a respected outside group . . . [to] undertake an analysis of how effectively [DOE] identifies, programs, and executes its plans to address risks [to public health and safety from the DOE’s remaining environmental cleanup liabilities], as well as how effectively the Defense Nuclear Facilities Safety Board (DNFSB) identifies and elevates the nature and consequences of potential threats to public health and safety at the defense environmental cleanup sites.” See “A Review of the Use of Risk-Informed Management in the Cleanup Program for Former Defense Nuclear Sites,” accessed March 2, 2017, http://www.tri-cityherald.com/news/local/hanford/article33023001.ece/BINARY/Omnibus%20Risk%20Review%20Report_FINAL.
which also concluded that within EPA there is need to integrate regulatory requirements, policies, and guidance under Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA, known also as Superfund) and RCRA (Omnibus, 2015, pp. viii-ix). Dr. Zhu further commented that agencies are already actively engaging in the use of performance assessments to guide risk-informed decisions on managing wastes. He noted that agencies have come together in recent years to compare processes and develop lessons learned and best practices in conducting performance and risk assessments for supporting decision making, including on disposal facility operations.
Ms. Edwards agreed that a comprehensive picture of the regulations across agencies would be valuable. To be able to show that there is a single framework guiding decisions on LLW disposal would be useful. Such a framework might also be able to show how different rules and regulations across the agencies work (or do not work) together.
4.6 FINAL THOUGHTS: COMMUNICATION
Mr. Applegate started the discussion about communications by talking about the meaning of the term “stakeholder.” He noted that there are many people involved with or affected by LLW disposal who have many different perspectives, levels of understanding of the issues, and objectives. He asked participants to describe what steps could be taken to improve communications with these different groups.
Ms. Edwards responded that communication and transparency with the public are important throughout the entire lifecycle of LLW. We are deficient in communicating about LLW not only because the system is difficult to explain, but also because radioactive waste is portrayed as a “boogeyman.” One approach is to avoid public discussion altogether, but this is a very short-sighted perspective. It may be difficult to communicate about the good protective measures that are being taken with radioactive waste, but it is our job to do so.
She recalled Dr. Goode’s comments about the public’s perception of a waste being affected by the perception of how the waste was generated or stored. For example, there may be more public support for disposal of radioactive waste from medical treatments than from weapons development or for the disposal of sealed sources to reduce terrorist threats. Even if the waste characteristics and hazards are similar, the fact that it was generated from different processes influences public perceptions. Perhaps there is an opportunity to communicate with the public about wastes it perceives as being generated from processes that are acceptable or valuable. It would at least open the possibility of a discussion of actual hazards and technical solutions that could be used to address those hazards. One could then
explain how waste from other processes could be managed. It would also be an opportunity to discuss disposal options that are commensurate with the level of hazard posed by the wastes.
Dr. Crowley noted that we have to change the way we talk to our stakeholders, as he explained earlier in the workshop (i.e. “educating the public”). He provided several suggestions. The first is to understand that there is not a public, there are publics. There are many different people at different levels that we need to communicate with, for example state legislators, city councils, concerned citizens, or even the League of Women’s Voters. We have to understand who those audiences are, and then we have to understand what they are interested in. And to do that, we have to go out and ask them. Communication begins with discussions with the publics to find out what their interests are and what their questions are. And then you have to try to answer those questions. A true dialogue is needed.
These concepts are well understood but difficult to implement. Dr. Crowley explained that the National Academies try to implement this approach for communicating with the public in some of the studies that they carry out, and he knows from these experiences that this type of communication is very difficult to do because we operate in a very low-trust environment, particularly with respect to the government. Dr. Crowley suggested that improving communications will be a long-term effort, and that it will take a long time to establish sufficient trust to have a useful dialogue.
Mr. Garamszeghy noted that the use of the term “talking to the public,” which has repeatedly been raised throughout the workshop, is indicative of the wrong attitude. Talking “at the public” or “to the public” turns people off. As mentioned by Dr. Crowley, it is necessary to talk with members of the public to understand what their concerns and issues are. Ask them what their needs are. Communication is a two-way street. Members of the public want to know and feel that they are being respected, their views are respected, and their input is valued.
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