This report is the product of a congressional request1 to the National Academies of Sciences, Engineering, and Medicine for an evaluation of the general viability of the Department of Energy’s National Nuclear Security Administration’s (DOE-NNSA’s) conceptual plans to disposition surplus plutonium material at the Waste Isolation Pilot Plant (WIPP). Dispositioning 34 metric tons (MT) of surplus plutonium is part of the Plutonium Management and Disposition Agreement (PMDA), an agreement between the United States and the Russian Federation. DOE-NNSA’s conceptual plans call for diluting the surplus plutonium material with a classified adulterant, declaring the diluted material as transuranic (TRU) waste, and emplacing the waste in WIPP. Specifically, the National Academies were asked to review DOE-NNSA’s plans to ship, receive, and emplace surplus plutonium in WIPP and to assess DOE-NNSA’s understanding of the impacts of these plans on WIPP and WIPP-bound waste streams. Ultimately, the National Academies were asked to evaluate the general viability of these conceptual plans. See Box 1-1 for the full Statement of Task.
1 The mandate appears in the Energy and Water Development Appropriations Bill (U.S. Congress, House, 2016, p. 114).
In 2018, DOE Secretary Perry announced the cancellation of the mixed oxide (MOX) fuel fabrication facility (Perry, 2018). As an alternative to disposition of surplus plutonium material through irradiated MOX fuel (as was agreed to under the PMDA; DOS, 2010), DOE-NNSA is preparing to use the dilute and dispose approach to disposition 34 MT, and conceivably up to 48.2 MT. The development of the plan was motivated by the need to identify a less costly alternative to the disposition of surplus plutonium material through its incorporation into MOX fuel and later irradiation in commercial nuclear reactors (i.e., the MOX approach). The Defense Nuclear Nonproliferation office within DOE-NNSA developed and is managing the dilute and dispose conceptual plan.
The committee released an Interim Report in November 2018 in order to meet congressionally mandated timelines; it is reproduced in full as Appendix H of this report (NASEM, 2018). The Interim Report provided a high level review of the proposed dilute and dispose process, discussion of the then-current understanding of WIPP capacity, and requirements of the PMDA. At the time of its release, several key planning documents and information such as National Environmental Policy Act strategies and decisions, WIPP criticality and performance assessments, plans for international monitoring and verification, and programmatic information contained within DOE-NNSA’s Life-Cycle Cost Estimate (LCCE) were not publicly available for the committee’s review. The committee has since received this information and additional briefings (see Appendix B).
This final report fully addresses the Statement of Task (see Box 1-1). Consequently, some text and content from the Interim Report are included. However, several topics that were not covered in the Interim Report will be described in greater detail than other topics in this final report. Specifically, these topics are the viability of DOE-NNSA’s conceptual plans on transportation safety, security, and regulatory compliance (Task 2.a), and pre- and post-closure safety and performance of WIPP (Task 2.d). The advice provided in the Interim Report is revisited and updated in this final report, with any changes noted. Advice in the final report supersedes any conflicting advice in the Interim Report.
The National Academies appointed a committee of 14 technical experts to carry out this evaluation; their biographies are provided in Appendix A. A subset of the committee and Academies staff with appropriate clearances were briefed on the classified aspects of the dilute and dispose plan; the subset of the committee did not produce a classified report. The committee held 18 meetings to gather information for this evaluation and prepare the Interim Report and this final report; agendas for the committee’s information-gathering meetings are provided in Appendix B.
1.1 INTERPRETATION OF THE STATEMENT OF TASK
The dilute and dispose program is a new program proposed by DOE-NNSA. Funding to allow DOE-NNSA to develop a preconceptual plan for dilute and dispose was allocated in 2016 (U.S. Congress, House, 2016, p. 115). DOE-NNSA has followed several guidance documents including the Government Accountability Office’s (GAO’s) Cost Estimation and Assessment Guide (GAO, 2009) and the DOE Directive for Program and Project Management for the Acquisition of Capital Assets (DOE Order 413.3B; DOE, 2010). The LCCE for the dilute and dispose plan was developed following GAO’s guide; planning documents from the LCCE were provided to the committee in late 2018.2 An independent review of the LCCE reports a cost estimate of $18.2 billion (in then-year dollars; DOE, 2018b3) for the disposition of 34 MT of surplus plutonium at WIPP (SRNS, 2018a). The amount is less than half the cost of the LCCE for the MOX approach, allowing DOE to cancel the MOX facility construction and move forward with dilute and dispose (Perry, 2018).
2 The full set of LCCE documents were not provided to the committee; the committee received only LCCE documents that were relevant to the committee’s tasking.
3 The estimate excludes $20 million in sunk costs. All cost estimates were developed in fiscal year 2017 dollars and converted to then-year dollars using escalation rates found in DOE, 2018b.
To date, DOE-NNSA’s dilute and dispose activities at the Savannah River Site (SRS) (i.e., dilution; see Chapter 2) have completed the Critical Decision 0 (CD-0), CD-1, and CD-3A process steps within the DOE 413.3B framework. The CD-0 milestone indicates that the mission need has been approved by DOE, demonstrating that “[t]here is a need that cannot be met through other than material means” (DOE, 2010, p. A-1). DOE’s approval of CD-1 in late 2019 indicated that “the selected alternative and approach is the optimum solution” (DOE, 2010, p. A-1); approval of CD-3A, phase 1, which allows DOE to begin required construction activities at SRS’s K Area prior to CD-2 approval, was granted in mid-February 2020.4
The level of maturity of DOE-NNSA’s plans is an important factor in the committee’s ability to assess viability. It has been a challenge to address the tasking at a detailed level because the plans are not yet fully developed. As the program evolves, the plans for dilute and dispose are expected to mature as additional details become better defined and incorporated into the planning.5 Therefore, in addition to evaluating the plans as they currently exist, the committee has identified areas or concepts that are either not included or insufficiently developed in the DOE-NNSA plans. Advice on how to incorporate these ideas into future development is provided.
After the release of its Interim Report, several technical documents and reports, such as the LCCE summary report (SRNS, 2018b), the WIPP post-closure criticality report (Saylor and Scaglione, 2018), and a draft performance assessment (Zeitler et al., 2018), were made available to the committee.6 The committee determined that comprehensive independent technical review of the same reports was outside of this committee’s Statement of Task (and the time and budget allowed for the project). Nevertheless, reasonable doubt or concern over stated assumptions or assessments within the reports may be noted by the committee. Finally, the committee recognizes that the authority and responsibility for the determination of pre- and post-closure safety rests with the Environmental Protection Agency (EPA), the State of New Mexico, DOE, or others, and that this report is advisory only.
The committee approached its tasking recognizing that the MOX approach is not an option for surplus plutonium material disposition and that continued storage as material is also not under consideration (but might be under an environmental impact assessment as a no-action alternative). Instead, it focused on currently planned approaches for dilution followed by disposal in WIPP, while noting that at some point in the future the United States may develop other geologic repositories for nuclear waste, which might be used for disposal of material of this type.
1.2 REPORT ROADMAP
This report is organized into five chapters. Each chapter was written to be read by itself so that readers who are interested in particular topics can focus their attention on an individual chapter. Chapters 2 and 3 provide background information and details of DOE’s dilute and dispose plans. Readers familiar with those topics might choose to read Chapters 4 and 5, in which the committee provides the majority of its assessments via findings, conclusions, and recommendations. Content in Chapters 4 and 5 refers back to details and diagrams found earlier in the report.
- Chapter 1 (this chapter) provides information about, and the committee’s interpretation of, the tasking for this study.
4 CD-2/3 will follow CD-3A approval.
5 As noted in the Surplus Plutonium Disposition Technical Baseline Description (SRNS, 2018d, p. 8): “This Guide recognizes that the ‘technical baseline tends to evolve as requirements become better defined.’”
6Zeitler et al. (2018, p. 13) make clear in their report that it is not a substitute for evaluating compliance: “The analysis is not in support of a planned change request (PCR) or planned change notice (PCN) to be submitted by the DOE to the EPA, and was not performed as a compliance calculation. Instead, the planned use of the analysis is as input into a National Environmental Policy Act (NEPA) analysis.”
- Chapter 2 provides background on topics that will be referenced throughout the report, including a summary of the U.S. surplus plutonium inventory; history and background on regulations and management of WIPP and TRU wastes; discussion of the PMDA between the United States and the Russian Federation; and a description of risk assessment.
- Chapter 3 describes DOE-NNSA’s dilute and dispose plan by location (Pantex, Los Alamos National Laboratory, SRS, and WIPP) and activities including transportation between the sites. Plans for scaling up operations and risks that have been identified are also discussed.
- Chapter 4 describes and assesses the viability of DOE-NNSA’s plans. Implementation challenges are identified and advice is provided to address the challenges, referencing the background in Chapter 2 and the plan description in Chapter 3.
- Chapter 5 identifies system vulnerabilities within the current plan and provides suggestions and advice on how to address these risks, which could threaten the successful, full completion of the program as planned. In its analysis, the committee refers to background in Chapter 2 and the plan description in Chapter 3.
The report has several appendixes that contain additional background and details including Appendix A: Committee and Staff Biographies; Appendix B: Meetings; Appendix C: How Salt Repositories Work; Appendix D: Legal and Regulatory Requirements for Transportation; Appendix E: States’ Active Partnership Role in Safe Transportation; Appendix F: High-Risk Items Within the Risk and Opportunity Analysis Report; and Appendix G: Acronyms and Abbreviations. The Interim Report is recreated in its entirety in Appendix H.
The committee distinguishes between findings, conclusions, and recommendations using the following criteria:
- Findings: Summary statements about the evidence with which no reasonable person could argue without rejecting the evidence—no judgment is involved.
- Conclusions: Judgments based on one or more findings or analysis of the evidence—never contain the word “should.”
- Recommendations: Proposed actions based on one or more conclusions—usually contain the word “should” and indicate an actor and an action.