1
Context and Setting

As described in previous review reports from the National Academies of Sciences, Engineering, and Medicine (the National Academies), the Hanford Nuclear Reservation is the site of the largest and most complex nuclear cleanup challenge in the United States (for background on the complexity of the cleanup challenge, see NASEM, 2020, 2022).

The U.S. Department of Energy’s Office of Environmental Management (DOE-EM) is responsible for managing and cleaning up the waste and contamination under a legally binding Tri-Party Agreement (TPA) with the Washington State Department of Ecology (the Department of Ecology) and the U.S. Environmental Protection Agency (EPA). DOE-EM has proposed to retrieve the waste from the Hanford Site’s tanks to produce two waste streams, high-level waste (HLW) and low-activity waste (LAW), by removing several specific radionuclides that constitute most of the radioactivity from the liquids and dissolved salt cake in the tanks, yielding liquid LAW, and then combining the removed radionuclides with the HLW solids. DOE-EM estimates that the HLW will contain more than 90 percent of the radioactivity and less than 10 percent of the total volume, while the LAW will consist of less than 10 percent of the radioactivity and more than 90 percent of the volume. This is primarily accomplished by removing “key radionuclides to the maximum extent practical” (DOE, 2011) during the processing of the waste streams in the Waste Treatment and Immobilization Plant (WTP), which has been under construction for the past two decades at the Hanford Site.

To treat these two waste streams, the current plan is to use vitrification, that is, immobilization in glass waste forms, for all of the HLW stream and for at least one-third of the direct (primary) LAW stream. Secondary LAW waste comprising liquid wastes, off-gas filters, and other internally generated wastes is expected to be grouted, that is, immobilized in a cementitious waste form. Because of capacity limits in the recently completed LAW vitrification facility portion of the WTP, DOE-EM anticipates that there will be substantial amounts of the LAW that the WTP cannot process. Note, the LAW facility is currently undergoing startup and commissioning.

To increase the LAW treatment capacity, DOE-EM intends to decide on a supplemental treatment approach and build another treatment facility to implement it. The supplemental LAW (SLAW) to be treated would be similar in composition to the LAW to be treated in the WTP. The immobilized LAW—whether from the WTP or the SLAW facility—is intended to be disposed of in the existing near-surface Integrated Disposal Facility (IDF) at Hanford, though more recently (NASEM, 2020) preliminary analysis has been done regarding off-site locations such as the Waste Control Specialists (WCS) facility near Andrews, Texas.

Presently, to keep the treatment of the HLW in the WTP on track over time to meet the amended TPA milestones, DOE’s plan is to have a supplemental treatment plant for the portion of the LAW that will exceed the capacity of the WTP (SLAW), because the SLAW must be treated concurrently to allow the HLW to be treated at the WTP’s full potential capacity. In DOE’s 2013 Record of Decision on Hanford tank waste management, DOE stated that it “does not have a preferred alternative regarding supplemental treatment for the LAW; DOE believes it is beneficial to study further the potential cost, safety, and environmental performance of supplemental treatment technologies” (DOE, 2013).

1.1 CONGRESSIONAL MANDATE TO CONTINUE THE ANALYSIS AND REVIEW OF SUPPLEMENTAL TREATMENT APPROACHES

DOE-EM has yet to formally select a supplemental treatment approach, although the Department of Ecology and some stakeholders assert that DOE has previously promised to use vitrification. To help

with the selection, Congress directed DOE in section 3125 of the Fiscal Year 2021 National Defense Authorization Act (Public Law 116-283) to enter a contract with a Federally Funded Research and Development Center (FFRDC) to “conduct a follow-on analysis to the analysis required by section 3134 of the National Defense Authorization Act for Fiscal Year 2017 (Public Law 114-328; 130 Stat. 2769) with respect to approaches for treating the portion of low-activity waste at the Hanford Nuclear Reservation, Richland, Washington, intended for supplemental treatment.” The analysis “shall be designed, to the greatest extent possible, to provide decision makers with the ability to make a direct comparison between approaches for the supplemental treatment of low-activity waste at the Hanford Nuclear Reservation based on criteria that are relevant to decision making and most clearly differentiate between approaches.” For the criteria that Congress wants considered, see Appendix A, which provides the complete texts of sections 3125 and 3134.

As specified in section 3134, the SLAW treatment approaches considered should at a minimum include:

1. Vitrification, to produce glass waste forms either using Joule-heated melters, which are to be used in the WTP, or bulk vitrification;
2. Grouting, to produce cementitious waste forms; or
3. Fluidized bed steam reforming (FBSR), to produce calcined granules (often analogized to the consistency of puffed rice) or a monolithic crystalline ceramic waste form.

Section 3125 also asks for additional analysis of the grout treatment options identified in the FFRDC’s report for section 3134.

In the previous section 3134 study (NASEM, 2020), the FFRDC considered in its final report five cases: (1) vitrification for disposal at the IDF, (2) grouting for disposal at the IDF, (3) grouting for disposal at WCS, (4) FBSR for disposal at the IDF, or (5) FBSR for disposal at WCS. In addition, secondary wastes, which were assumed to be grouted in all cases, are produced in amounts that depend on the treatment alternative, and these can contribute significantly to the dose rate to a public receptor. To implement the alternatives, additional waste conditioning (pretreatment) might be needed, for example, to remove certain radionuclides, or adjust the composition of the waste to make it more suitable or less costly for treatment and disposal.

In parallel to selecting an FFRDC, DOE was directed in section 3125 to contract with the National Academies to conduct a concurrent, iterative review of the FFRDC report as it develops to inform and improve the FFRDC’s work.¹ DOE contracted with Savannah River National Laboratory (SRNL), an FFRDC, and then SRNL formed a team of experts from SRNL and other DOE national laboratories as well as from outside the laboratories’ network. The charge to the FFRDC team from section 3125 is in Appendix A. The Statement of Task (SoT) for the National Academies’ committee is in Appendix B.

The FFRDC team’s task is to provide DOE and Congress with a side-by-side comparison of the alternative treatment approaches and disposal options to aid decision making. The committee, as peer reviewer, does not offer or wish to imply that it is making any recommendation among alternative approaches.

1.2 STUDY PROCESS

In the first review report, this National Academies’ committee published a peer review of the FFRDC’s draft framework report of 74 pages, titled “Hanford NDAA 3125 FFRDC Working Draft Compilation,” dated September 30, 2021, and a set of 71 slides produced by the FFRDC and presented at the

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¹ For clarity, to the extent possible, this review report uses the nomenclature of team for the FFRDC’s investigators, committee for the National Academies’ committee, draft report for the FFRDC team’s work, and review or review report for the committee’s work.

public meeting on October 20-21, 2021.² The committee also took into account presentations at the two public meetings and comments submitted by stakeholders and other interested members of the public (NASEM, 2022). The committee’s review was published in January 2022 (NASEM, 2022). Following the publication, the sponsor of the study and other stakeholders were briefed by the co-chairs of the committee. The FFRDC team was also briefed to clarify the findings and recommendations and answer any questions concerning the review.

On April 12, 2022, the National Academies’ committee was provided with the second report from the FFRDC team for review. The report was titled “Follow-on Report of Analysis of Approaches to Supplemental Treatment of Low-Activity Waste at the Hanford Nuclear Reservation,” (Bates, 2022a) a 191-page report with 579 pages of supporting information (Bates, 2022b). It is also publicly available on the National Academies’ website.

A public meeting was held in Richland, Washington, on April 26-28, 2022. The full agenda and the list of presentations are provided in Appendix C. The meeting included an update from the DOE Hanford Office of River Protection and Washington River Protection Solutions, a restricted site tour of the Hanford Site to show the progress being made at several of their facilities, presentations from the FFRDC team, invited presentations from the U.S. Government Accountability Office, the Department of Ecology, the Oregon Department of Energy, and the Yakama Nation. Regional stakeholders were also given opportunities for presentations, and a 60-day public comment period was available from April 12 to June 12. The public comments are included in Appendix C. Note that section 3125 by reference to section 3134 specifies that “the National Academies of Sciences, Engineering, and Medicine shall provide an opportunity for public comment, with sufficient notice, to inform and improve the quality of the review.” Also, section 3134 highlights the necessity of consultation with Washington State and an opportunity for it to comment on the FFRDC’s draft reports. The committee appreciates the ongoing input from the Department of Ecology.

An updated schedule is shown in Table 1-1 for the FFRDC’s work, the committee’s review, the public meetings, and the briefings to stakeholders. The next public meeting, in Richland, Washington, and with an online connection option, is planned for January 2023. The National Academies will publicly announce the specific dates for the meeting once these have been determined.

To perform its peer review task, the National Academies formed a committee composed of 14 experts and 1 technical consultant whose expertise spans the issues relevant for reviewing the FFRDC’s analysis, including risk assessment, cost estimation, cost-benefit analysis, waste pretreatment, supplemental treatment approaches, legal and regulatory requirements, and large-scale nuclear construction projects. Several of the committee members have prior experience in studying cleanup activities at the Hanford Nuclear Reservation, as well as at other DOE-EM sites. Appendix D contains biographical information about the committee members’ qualifications and experiences. Any information learned by the committee during additional factfinding will be made available in the study’s Public Access File.³

The committee’s review is constrained by the SoT, which expressly calls for the committee to “evaluate the technical quality and completeness” of the FFRDC report on the treatment options for the SLAW. The SoT also requires that the committee’s report be “technical,” and the committee’s scope (along with the FFRDC’s) is the considered treatment approaches to the SLAW.

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² To access all these documents and presentations from the public meetings, please go to nationalacademies.org and enter the search terms “Review of the Continued Analysis of Supplemental Treatment of Low-Activity Waste at the Hanford Nuclear Reservation.” This search will show the hyperlinks to the public meetings and provide access to the recordings of the events as well as the FFRDC draft documents and other presentations.

³ To request information in the Public Access File for this project, see https://www8.nationalacademies.org/pa/managerequest.aspx?key=DELS-NRSB-21-01.

TABLE 1-1 Study Schedule

1.3 REVIEW REPORT ORGANIZATION

The remainder of this review consists of the committee’s assessment, findings, and recommendations to respond to the three questions in the SoT.

1. Does the FFRDC’s report clearly lay out a framework of decisions to be made among the treatment technologies, waste forms, and disposal locations?
2. Does the FFRDC’s report consider in its analysis all the elements, criteria, and factors specified in section 3125 of the National Defense Authorization Act of 2021?
3. Does the FFRDC’s report provide additional analysis for the grout treatment approach as identified in the FFRDC report for section 3134 of the National Defense Authorization Act of 2017?

These findings and recommendations are in Chapter 2. Developing the narrative for this consensus study, the review committee used the following outline for a structured approach to answer all of the requirements in the National Defense Authorization Act. Relevant experts proposed findings and recommendations in each of the areas below that were used to assemble the final study.

Statement of Task Question #1: Did the FFRDC lay out a framework of decisions that can be used to determine the proper treatment for SLAW?

1. Is it a framework of decisions?
2. Did the FFRDC select the appropriate criteria?
   1. Long-term effectiveness
   2. Implementation schedule and risk
   3. Likelihood of successful mission completion
   4. Life-cycle costs
   5. Regulatory approval
   6. Community and public acceptance
   7. Other criteria
3. Did the FFRDC select the appropriate alternatives?
   1. Vitrification 1: Single vitrification plant, on-site disposal
   2. FBSR 1A: Fluidized Bed Steam Reformer, on-site disposal
   3. Grout 4B: Off-site vendor for grouting, and off-site disposal
   4. Grout 6: Phased off-site and on-site grouting and disposal
4. Presentation/comparison of alternatives
5. The FFRDC’s Formal Recommendation

Statement of Task Question #2: Did the FFRDC consider all of the congressionally required elements?

Statement of Task Question #3: Did the FFRDC give “additional analysis” of grout?

Chapter 3 contains numerous additional observations by the committee. These are not formal findings or recommendations. Rather, in the spirit of a peer review, they are points for consideration by the FFRDC as it completes its final report.