Summary

The United States has declared more than 60 metric tons (1 MT is 1,000 kilograms) of weapons-grade plutonium as surplus (i.e., plutonium that has no programmatic use and does not fall into one of the categories of national security reserves). No single document describes disposition plans for the entirety of the U.S. surplus plutonium inventory.¹ Rather, disposition decisions depend on the form of the plutonium which can lead to different disposition pathways. Since the mid-1990s, disposition plans for the U.S. surplus plutonium inventory have evolved. Figure S-1 presents surplus plutonium amounts and varieties of surplus plutonium material and describes current disposition plans. Thirty-four metric tons are associated with the Plutonium Management and Disposition Agreement (PMDA, discussed later in this Summary) and have recently been proposed by the Department of Energy’s National Nuclear Security Administration (DOE-NNSA) for dilution and disposal in the Waste Isolation Pilot Plant (WIPP, also discussed later in this Summary). However, additional amounts are associated with DOE’s dilution and disposal plans, some of which are managed by DOE’s Office of Environmental Management (DOE-EM).² Therefore, this report reviews and assesses the viability of DOE’s plans to process up to 48.2 MT of surplus plutonium—the amount that is under consideration or slated for disposal—as diluted surplus plutonium transuranic (DSP-TRU) waste in WIPP.³

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¹ Disposition refers to the treatment of plutonium material to render it unusable for weapons, while disposal refers to the emplacement of waste in a geologic repository without the intention of retrieval.

² DOE-EM uses the term “downblend” while DOE-NNSA uses the term “dilute” to describe the process for mixing surplus plutonium with an adulterant to ensure that plutonium “is not recoverable without extensive reprocessing” (SRNS, 2016, p. 8). The committee uses “dilute” throughout this report.

³ Transuranic waste is defined in Section 2 of the Waste Isolation Pilot Plant Land Withdrawal Act (LWA), Pub. L. No. 102-579, 106 Stat. 4777-4796 (1992) (as amended in 1996 by Pub. L. No. 104-201, https://www.congress.gov/104/crpt/hrpt540/CRPT-104hrpt540-pt1.pdf, accessed March 29, 2020).

In 2000, 34 MT of the surplus were to be dispositioned through incorporation of oxidized plutonium into nuclear fuel rods (mixed oxide, or MOX fuel) for irradiation in commercial nuclear reactors. Additional surplus plutonium would be immobilized with high level waste (DOE, 2000).⁴ In both cases, high levels of radiation made recovery of the source plutonium difficult. The U.S. government later decided to pursue only the MOX approach (DOE, 2002).

In parallel to these actions, the United States and Russia each committed via the PMDA to disposition at least 34 MT of surplus plutonium. In 2000, Russia agreed to incorporate all 34 MT into MOX fuel to be irradiated in nuclear power reactors while the United States agreed to the dual-pathway approach. In 2010, the PMDA was renegotiated so that the United States and Russia would both disposition at least 34 MT of surplus plutonium as irradiated MOX fuel (DOS, 2000, 2010).

In the early 2000s, the U.S. government moved forward with plans to build a MOX fuel fabrication facility (MOX plant) in South Carolina at the Savannah River Site (SRS). The MOX project involved activities at DOE sites across the United States (i.e., the Pantex Plant in Texas and the Los Alamos National Laboratory [LANL] in New Mexico), but South Carolina would see the largest increases in the amount of plutonium that it would accept to execute the MOX plan. A 2002 federal law outlined schedules for the MOX plant operation with penalties to be paid to the State of South Carolina if not met.⁵

By the mid-2010s, the construction of the MOX plant was behind schedule and the costs for its completion had greatly increased. DOE-NNSA began exploring, through a set of studies, other options for dispositioning the 34 MT of surplus plutonium (DOE, 2014; Mason, 2015; Parsons, 2017). Those studies found that a dilute and dispose approach—diluting the oxidized plutonium material with an inert adulterant to a level that would meet PMDA requirements while meeting the waste acceptance criteria for disposal as TRU waste at WIPP—was the most viable and least expensive option.

WIPP is the nation’s only operational deep geologic repository for nuclear waste. It is licensed to receive only defense TRU waste and has a capacity established by law of 175,564 cubic meters (m³).⁶ WIPP is a salt bed repository (see Figure S-2). Panels each the size of several football fields are mined out of the salt bed more than 2,000 feet underground, and TRU waste is emplaced in rooms within the panels. After WIPP is full, the repository will close access to the underground panels and allow the salt to encase the TRU waste (defined as post-closure operations). Safety and performance analyses of WIPP for operations and for post-closure have shown that, if undisturbed, the probability of releases from the underground to the environment are extremely low.

WIPP is located in the southeast corner of New Mexico, in the Permian Basin. This area was recently identified as having the largest gas and oil reserves in the United States (Gaswirth et al., 2018). Surrounding WIPP are an increasingly dense number of drill sites. WIPP’s post-closure safety analysis takes into account human intrusion scenarios (e.g., drilling) and indicates that the estimated releases are within regulatory maximums. Based on the independent review of these analyses, the Environmental Protection Agency (EPA, which regulates WIPP) has continued to certify WIPP since its operations began in 1999.

The vast majority of defense TRU wastes emplaced in WIPP are contaminated products that result from working with plutonium and other actinide elements including clothing, tools, rags, residues, debris, and soil. As of the end of September 2019, a total of 180,225 waste containers of various sizes and types have been emplaced in WIPP; the majority, about 70 percent, are 55-gallon drums (see Table 5-1). Three

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⁴ For definition, see https://www.nrc.gov/waste/high-level-waste.html (accessed March 8, 2020).

⁵ The MOX plant was expected to produce 1 MT of MOX fuel by December 31, 2009, and 34 MT by January 1, 2019. If not achieved, DOE would pay the State of South Carolina penalties not to exceed $100,000,000 per year until either the MOX objective is reached or DOE removes at least 1 MT of defense plutonium or plutonium materials from the state per year (Bob Stump National Defense Authorization Act for Fiscal Year 2003, Pub. L. No. 107-314, § 3182, 116 Stat. 2458, https://www.govinfo.gov/content/pkg/PLAW-107publ314/html/PLAW107publ314.htm, accessed March 29, 2020).

⁶ Waste Isolation Pilot Plant Land Withdrawal Act (LWA), Pub. L. No. 102-579, 106 Stat. 4777-4796 (1992) (as amended in 1996 by Pub. L. No. 104-201, https://www.congress.gov/104/crpt/hrpt540/CRPT-104hrpt540-pt1.pdf, accessed March 29, 2020).

types of 55-gallon drums are relevant to this report (see Figure S-3): the direct-loaded 55-gallon drum, the pipe overpack container (POC), and the criticality control container/criticality control overpack (CCC/CCO). Per DOE’s plans, DSP-TRU waste will be placed into a CCC, which is positioned inside of a CCO.

In fiscal year (FY) 2016, MOX plant construction continued to run over budget and timelines, and no commercial nuclear power plant had yet formally agreed to accept the fuel. That same year, Congress appropriated $5 million for DOE-NNSA to begin to develop a conceptual plan to dilute and dispose surplus weapons-grade plutonium. This plan, if finalized, would provide an alternative to the MOX option. In FY 2017, Congress appropriated additional funds to DOE-NNSA’s planning effort ($15 million) while also directing it to contract with the National Academies of Sciences, Engineering, and Medicine to independently review and assess the viability of its early dilute and dispose plans. Central to the plan’s concept is disposal of diluted surplus plutonium material as TRU waste in WIPP (see Figure S-4). The National Academies were asked to also explore the impact of DOE-NNSA’s plans on WIPP operations and the disposal of other TRU waste streams. Another important component of the tasking was to review how well the dilute and dispose plan met the PMDA (DOS, 2010).

An independent review of DOE-NNSA’s plan to dilute and dispose of 34 MT of surplus plutonium estimates that the effort will take 31 years and $18.2 billion to complete (in then-year dollars⁷), beginning with conceptual design in 2018 and ending with emplacement of the full amount of DSP-TRU waste in WIPP in 2049 (DOE, 2018b). First emplacements of DSP-TRU waste in WIPP derived from non-pit and pit plutonium material are FY 2023 and FY 2028, respectively.⁸

COMMITTEE’S ASSESSMENT

The committee issued an Interim Report in late 2018 summarizing its initial findings, conclusions, and recommendations and highlighting remaining issues to be addressed in this final report. A determination of the viability of DOE-NNSA’s plans was not made due to lack of sufficient information. The Interim Report highlighted concerns over the lack of concurrence with the PMDA requirements, statutory and physical capacities at WIPP, and the need for sustained support for the length of the planned effort (over 30 years). Having received additional information, the committee revisits those concerns and addresses its remaining tasks—review of transportation and of pre- and post-closure safety of WIPP.

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⁷ The estimate excludes $20 million in sunk costs. All cost estimates were developed in FY 2017 dollars and converted to then-year dollars using escalation rates found in DOE, 2018b.

⁸ The remaining 8.2 MT, from a total of 42.2 MT, is not included in the current schedule; see Figure 3-1 in Chapter 3.

The committee determined that DOE-NNSA’s early-stage plans to dilute and dispose at least 34 MT of surplus plutonium provide a technically viable disposition alternative to the MOX plan, provided that implementation challenges and system vulnerabilities that currently exist within the plan are resolved. The rationale for this conclusion is that the individual process steps of the DOE-NNSA dilute and dispose plan have nearly all been demonstrated by a variety of different DOE programs. For example, the plan utilizes the existing MOX plans to process surplus plutonium into plutonium oxide. Equipment and resources will be shared with DOE-EM’s current efforts to dilute and dispose of 6 MT of surplus plutonium (see Figure S-1). The plan uses existing and well-established transportation programs such as the Office of Secure Transportation and TRU waste transport for moving the material or waste between sites. Finally, DOE references previous emplacements of similar wastes (diluted and undiluted plutonium) in WIPP.⁹

However, all of the steps described in the dilute and dispose plan have not been sequentially demonstrated from start to end, posing a risk because even well-established capabilities run into unforeseen problems when integrated. Additionally, the process steps have been demonstrated at prototype levels, not at the scale that DOE-NNSA’s plans propose. For example, DOE-EM’s efforts to process up to 6 MT are less mature than previously understood. Only a very small amount of material (0.052 MT, as of the end of September 2019) has been processed by DOE-EM, and that material has not yet been transported from SRS to WIPP. Furthermore, DOE-EM’s plans indicate a completion date of 2046—meaning that DOE-EM’s and DOE-NNSA’s dilute and dispose activities will concurrently operate for nearly the full duration of DOE-NNSA’s dilute and dispose program.

Also, DOE-NNSA’s plan to disposition the surplus plutonium via dilute and dispose is neither recognized nor approved by the existing PMDA. This assessment has not changed since the committee issued its Interim Report. Furthermore, international monitoring and verification of the dispositioned surplus plutonium is a requirement of the PMDA but its adherence by DOE’s plans is unclear. Although nearly all of the processing steps for the dilute and dispose plans have been previously demonstrated by other DOE programs, as noted above, the details of monitoring and verification of the diluted and emplaced waste have not been defined for the DOE-EM or the DOE-NNSA dilute and dispose plans.

RECOMMENDATION 5-1: Plans for the International Atomic Energy Agency (IAEA) or other monitoring and inspection protocols have not yet been established for the disposition of the material identified in the Plutonium Management and Disposition Agreement (i.e., 34 metric tons of surplus plutonium) as diluted surplus plutonium transuranic (DSP-TRU) waste in the Waste Isolation Pilot Plant. Prior to emplacement of the DSP-TRU waste by the Department of Energy’s (DOE’s) Office of Environmental Management or DOE’s National Nuclear Security Administration (DOE-NNSA), DOE-NNSA and higher-level DOE officials should clarify their intent with respect to whether there will be IAEA monitoring and inspections for this material (and preferably before DSP-TRU waste is disposed of).

WIPP’s disposal capacity limits are defined by several different laws, agreements, and permits. As noted above, the LWA limits TRU waste disposal capacity to no greater than 175,564 m³ of defense-related TRU waste, a limit that is overseen by EPA. WIPP’s Hazardous Waste Permit, overseen by the State of New Mexico through its Environment Department (NMED) under the Resource Conservation and Recovery Act (RCRA), may also limit waste volumes through the size limitation of the underground waste panels. Until recently, the capacity limits for LWA and RCRA (Hazardous Waste Permit) were measured by the gross internal volume of the outermost disposal containers and were equivalent.

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⁹ The committee was initially told that 4.8 MT of plutonium had been downblended/diluted and disposed of at WIPP but was later told that the majority was not a waste form analogous to the DSP-TRU waste currently proposed by DOE. Using the Waste Data System/WIPP Waste Information System, the committee identified 61 kg of diluted plutonium within a total of 666 POCs that have been emplaced in WIPP.

Shortly after the release of the Interim Report, NMED approved a WIPP permit modification that distinguishes between reporting against the LWA capacity limits and the RCRA TRU mixed waste (TMW) capacity limits and allows for a recalculation of the volumes of emplaced and future wastes.

The committee was asked to review additional TRU waste streams and to assess DSP-TRU waste’s potential impact on them as well as the impact on LWA capacity limits. To reassess these impacts against the new volume of record (VoR) calculations, the committee updated the volumes of specific waste streams noted in its Interim Report: Greater-Than-Class-C-like wastes, tank wastes, and TRU waste generated by pit production. Recent DOE-reported volumes for emplaced and future TRU wastes were used (DOE-CBFO, 2018a, 2019a; see Table 3-2). The results shown in Figure S-5 highlight two main issues:

• Under the VoR recalculation, the LWA volume of the DSP-TRU waste generated by processing 48.2 MT of surplus plutonium is reduced from 33,740 m³ to 2,056 m³, which is approximately 1 percent of the LWA capacity, yet the physical volume is substantial (approximately the physical space of two panels); and
• When additional TRU wastes volumes are taken into account, the LWA capacity will still be challenged—primarily due to initial estimates with potentially large uncertainties of TRU waste from pit production.

RECOMMENDATION 3-1 (modified from Interim Report RECOMMENDATION 1): Capacity at the Waste Isolation Pilot Plant (WIPP) should be treated as a valuable and limited resource by the Department of Energy (DOE). DOE is able to prioritize national security mission waste streams for WIPP (i.e., pit production transuranic [TRU] waste). Because emplacement in WIPP is critical to both DOE’s Office of Environmental Management’s (DOE-EM’s) and DOE’s National Nuclear Security Administration’s (DOE-NNSA’s) dilute and dispose plans, the DOE-NNSA Administrator, in consultation with the DOE-EM Assistant Secretary, should prioritize and reserve Land Withdrawal Act capacity in WIPP for the full amount of diluted surplus plutonium TRU waste (2,057 cubic meters). Otherwise, the DOE-NNSA and the DOE-EM programs are at risk of not being able to disposition the full amount of 48.2 metric tons of surplus plutonium via dilute and dispose.

Acknowledging these updates from the Interim Report, the final report focuses on program execution challenges and discusses two types of findings, conclusions, and recommendations: One set focuses on programmatic implementation challenges and another on system vulnerabilities.

IMPLEMENTATION CHALLENGES

DOE-NNSA’s dilute and dispose option is likely to face implementation challenges (see Chapter 4) during its inception and lifetime of more than three decades including space and resource competition with pit production activities at LANL and SRS, and TRU waste emplacement in WIPP. Implementation challenges that are not addressed could lead to extended timelines and increased costs. None of the implementation challenges identified threaten the technical viability of the plan and many of these challenges could be addressed through improved project plans (as they mature and with independent review) and sufficient, steady funding from Congress. However, such straightforward approaches may not be adequate for some challenges, for example, the ability to hire and qualify sufficient staff or the resilience of the nuclear facilities.

A major implementation challenge is the scaling up of current individual operations to a future processing system that can safely and securely generate, transport, and dispose of the DSP-TRU waste within the desired schedule. Other challenges are maintenance of the infrastructure and expanded trained workforce that will be required for at least 30 years.

Security of the surplus plutonium and DSP-TRU waste was a major concern of the committee and can be summarized by the fact that DSP-TRU waste is not characteristically like the vast majority of previous TRU waste streams, and the standard operating procedures developed for traditional TRU waste may not be sufficient for DSP-TRU. The committee determined that the diluted plutonium does not meet the spent fuel standard and the dilute and dispose option has fewer barriers to recovery than the MOX option, including the loss of a radiation barrier. Furthermore, once emplaced and without monitoring in place,¹⁰ DSP-TRU waste could be retrieved and reprocessed by the United States (in fact, retrieval of emplaced waste post-closure is a WIPP recertification requirement). With sufficient mining expertise (which is becoming more common) and resources, non-state or third-state actors could retrieve emplaced DSP-TRU waste during the post-closure period with its absence left undetected (Tracy, 2019). Other concerns include the increased number of transports of pits, plutonium oxide, and DSP-TRU wastes as well as security concerns over DSP-TRU waste and WIPP operating procedures (including aboveground storage and inventory control of classified waste streams of significant quantity¹¹). DOE-NNSA will need

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¹⁰ WIPP does not currently have plans for underground sensors to monitor the emplaced waste after closure (i.e., after the underground is sealed and the facility is decommissioned).

¹¹ WIPP has emplaced classified TRU waste in the past but of limited quantities (see April 17, 2019, committee discussion, DOE [NNSA and EM] Follow-up to Address Unanswered Questions from Day One, https://vimeo.com/showcase/6028445/video/338029961, accessed May 20, 2020).

to ensure that a security program is in effect and is appropriate to DOE’s assessment of the attractiveness of the diluted plutonium material—and is periodically reassessed and updated.

Details of security assessments or updates were not available to the committee for two reasons: the full committee did not hold clearances for access to classified information and, more importantly, the security and risk assessments were not yet complete. As a result, the committee developed the following recommendation:

RECOMMENDATION 5-4 (updated Interim Report RECOMMENDATION 4): In addition to and separate from the independent review organization representing the State of New Mexico described in Recommendation 5-3, periodic reviews for Congress and the Department of Energy (DOE) by a team of independent technical experts should be required until classified aspects of DOE’s National Nuclear Security Administration’s and DOE’s Office of Environmental Management’s dilute and dispose plans, including the safety and security plans, are completed and implemented. Because DOE’s plans and decisions are expected to mature and evolve, these independent reviews would provide a mechanism to review classified aspects of the programs and would improve public trust in those decisions.

SYSTEM VULNERABILITIES

Several system vulnerabilities exist within the current plan (see Chapter 5). If not addressed, they could have serious consequences for the program and its mission to dispose of at least 34 MT—and as much as 48.2 MT—of surplus plutonium in an efficient, safe, and secure manner. System vulnerabilities include

• WIPP as the single point of failure for the disposal of DSP-TRU waste;
• the changing nature of WIPP with the full amount of DSP-TRU emplacement and shifting public opinion; and
• plans that span multiple DOE sites, offices, functions, and priorities without clear crosscutting leadership support.

An inability of WIPP to accept and emplace TRU wastes is a single point of failure for the dilute and dispose programs as well as for other DOE TRU waste programs. Future accidents resulting in lengthy shutdowns, such as those that occurred in 2014, pose a risk to access for the dilute and dispose programs but so do agreements and priorities of other programs (Idaho National Laboratory shipments or pit production) or other state legal requirements. The risks associated with conflicting priorities of other programs were not captured in DOE-NNSA’s Risk and Opportunity Analysis Report (SRNS, 2018c). Additionally, two significant changes in WIPP’s operations will be needed to allow for the emplacement of the DSP-TRU waste streams: expansion of underground configuration and an extension of the lifetime of WIPP. These changes have not yet been reviewed or approved by NMED and EPA.

When WIPP was being constructed and undergoing licensing in the 1990s, a social contract was established between DOE and the citizens of New Mexico in which WIPP’s mission and the types of wastes that were to be emplaced were outlined. A change in that understanding needs to be recognized even if the proposed DSP-TRU waste inventory is expected to meet the WIPP waste acceptance criteria (WAC) and EPA regulations. Senator Pete Domenici, who was a central figure in successfully bringing WIPP to New Mexico, wrote in a letter to Secretary of Energy Abraham:

By virtually any measure (see Table S-1), the proposal to dilute up to 48.2 MT of surplus plutonium and dispose of the DSP-TRU waste in WIPP represents substantial changes to the physical, radiological, and chemical composition of emplaced wastes and the “social contract” for WIPP and the State of New Mexico. No previous waste stream has affected the technical measures of WIPP performance at the same levels. While the initial analyses indicate that the WIPP repository will maintain regulatory compliance with the increased amount of plutonium in its inventory, the potential for such substantive changes raises technical, social, and political questions that translate to additional system vulnerabilities if not addressed. These differences must be recognized in their entirety to have a transparent and complete assessment of the DSP-TRU waste’s impact on WIPP and its associated operations (including transportation).

To improve transparency and understanding of DOE’s future plans for dispositioning of surplus plutonium as DSP-TRU in WIPP, the committee recommends the following:

RECOMMENDATION 5-7: The Environmental Protection Agency, the Department of Energy, and the State of New Mexico should engage in developing a mutually agreed-upon strategy for vetting the effects of the dilute and dispose inventory, in its entirety (and as added to the rest of the projected and emplaced inventory), on the Waste Isolation Pilot Plant. This vetting could be through a special demonstration of compliance and certification, or other means all agree to, but should occur before committing the substantial resources that will be needed to implement an integrated (48.2 metric tons of surplus plutonium) dilute and dispose program.

To further improve transparency and public trust in DOE decisions, the committee recommends reinstatement of the Environmental Evaluation Group (EEG).

RECOMMENDATION 5-3 (updated Interim Report RECOMMENDATION 3): If the Department of Energy’s (DOE’s) National Nuclear Security Administration’s dilute and dispose plan moves forward, DOE should reinstate the Environmental Evaluation Group (EEG), representing the concerns of the State of New Mexico, throughout the lifetime of processing up to 48.2 metric tons of surplus plutonium material. The independence of the EEG should be supported through mechanisms similar to those established in its original founding. Members of the technical review organization should be technically qualified to address the health and safety issues and a subset should have access authorizations that will allow thorough review of classified aspects of the plans and their implementation.

To address concerns related to plans spanning multiple DOE sites, offices, functions, and priorities without crosscutting leadership support, the committee recommends the following:

RECOMMENDATION 5-5: The Department of Energy should implement a new comprehensive programmatic environmental impact statement (PEIS) to consider fully the environmental impacts of the total diluted surplus plutonium transuranic waste inventory (up to an additional 48.2 metric tons) targeted for dilution at the Savannah River Site and disposal at the Waste Isolation Pilot Plant (WIPP). Given the scale and character of the diluted surplus plutonium inventory, the effect it has on redefining the character of WIPP, the involvement of several facilities at several sites to prepare the plutonium for dilution, a schedule of decades requiring sustained support, and the environmental and programmatic significance of the changes therein, a PEIS for the whole of surplus plutonium that considers all affected sites as a system is appropriate to address the intent and direction of the National Environmental Policy Act and would better support the need for public acceptance and stakeholder engagement by affording all the opportunity to contemplate the full picture.

TABLE S-1 Characteristics and Relevant Amounts and Volumes for Contact-Handled (CH) TRU and Diluted Surplus Plutonium (DSP) TRU Wastes Compared to Wastes in Other 55-Gallon Drum Containers

	Other TRU Waste	TRU Waste in Pipe Overpack Containers (POCs)	DSP-TRU Waste in Criticality Control Containers/Criticality Control Overpacks (CCC/CCOs)
Composition	Variable: contaminated clothing, tools, rags, residues, debris, soil, and other items	Plutonium residues, heterogeneous debris, salts, and sealed sources	Predictable composition of DSP-TRUa
Physical volume (outer container)	0.21 m3	0.21 m3	0.21 m3
LWA volume (inner container)	0.21 m3	0.046 m3	0.013 m3
Current total number of waste streams	202b	48b	3c
Total number of emplaced containers	97,928 (emplaced)d	27,025 (emplaced)d	160,667 (anticipated)e
Total amount of plutonium-239	1.6 MT (emplaced)	3.2 MT (emplaced)	48.2 MT (anticipated)
Percentage of plutonium-239 in total inventory at closure (10,000 years)f	15	[included in “Other TRU Waste”]	85
Average amount of plutonium-239 per container/fissile gram equivalent (FGE) limitg	14.4 g/£ 200 g	117 g/≤ 200 g	300 g (nominal)/ ≤ 380 g
Material attractiveness levelh	Level E	Varied	Level Di
Classification	Unclassifiedj	Unclassifiedj	Classified aspects (i.e., adulterant)i

^a Technical Baseline Description, SRNS, 2018b.

^b Number of waste streams derived from WDS/WWIS as of September 30, 2019, from https://wipp.energy.gov/WDSPA, accessed May 20, 2020.

^c SR-KAC-PuOx, SR-KAC-PuOx-1, SR-KAC-SPD (DOE-CBFO, 2019b; Dunagan et al., 2019).

^d Emplaced 55-gallon, direct loaded containers or POCs through September 30, 2019; see Table 5-1.

^e Assumes nominal 300 g per container.

^f Dunagan et al., 2019.

^g Per WIPP WAC, table 1, DOE-CBFO, 2018c.

^h See Box 3-2 for a description of attractiveness levels.

ⁱ See System Requirements, DOE-NNSA, 2018.

^j A small number of emplaced containers are known to be classified (Sahd, 2019); no further details are available.

To address concerns of shifting public opinion of DOE-NNSA’s plans and its handling of plutonium stockpiles and surplus inventory, the committee recommends the following:

RECOMMENDATION 5-6: The Department of Energy’s (DOE’s) National Nuclear Security Administration, DOE’s Office of Environmental Management, and DOE higher-level officials should take additional actions beyond those defined by the National Environmental Policy Act toward transparency and stakeholder engagement on the whole of the potential scope of surplus plutonium under consideration (48.2 metric tons) for disposal at the Waste Isolation Pilot Plant. Such actions include completing and publicizing the outcome of relevant safety analyses and cost estimates.