Summary

Section 3134 of the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328) (Sec. 3134) calls for a Federally Funded Research and Development Center (FFRDC) “to conduct an analysis of approaches for treating the portion of low-activity waste (LAW) at the Hanford Nuclear Reservation” intended for supplemental treatment.¹ The U.S. Department of Energy (DOE) has contracted with Savannah River National Laboratory (SRNL), an FFRDC, to provide the called-for analysis. SRNL then assembled a team of experts from SRNL and other national laboratories to perform the analysis. Sec. 3134 also calls for the National Academies of Sciences, Engineering, and Medicine (the National Academies) “to conduct a review of the analysis” performed by the FFRDC that is independent of and concurrent with the FFRDC’s analysis “to improve [its] quality….” The complete text of the congressional mandate in Section 3134 is provided in Appendix A, and the Statement of Task for the National Academies review is provided in Appendix B.

This review report, the second of four to be issued by the National Academies to address the congressional mandate, focuses on the Statement of Task’s study charge 4: “Results of the assessments, including the formulation and presentation of conclusions and the characterization and treatment of uncertainties.” The committee’s review is based on the FFRDC’s draft report of 197 pages submitted to the committee on July 16, 2018, and a set of about 200 slides produced by the FFRDC and presented at the public meeting on July 23-24, 2018, in Richland, Washington, as well as other public presentations at that meeting.

The committee’s overarching task is to provide a concurrent, independent peer review of the ongoing FFRDC analysis. The committee is neither charged to analyze the supplemental treatment approaches, nor to recommend any particular approach over another. Equally important, the committee notes what is not in the scope of the FFRDC’s analysis and the committee’s review, namely, tank waste management, high-level waste (HLW) processing and treatment, and the Waste Treatment and Immobilization Plant’s (WTP’s) design, construction, and operations. Indeed, the FFRDC itself will not identify a preferred option for supplemental treatment, but instead will evaluate the treatment alternatives against the baseline as well as against one another. It will provide (existing) data and analysis to enable DOE, with congressional oversight, to make an informed decision whether to use vitrification, grouting, fluidized bed steam reforming, or other identified treatment approaches to process supplemental LAW (SLAW) into waste forms for disposal.

Given that the FFRDC’s draft report has many chapters and sections for the summaries of the analytic results labeled “TBD,” and given other gaps in the draft report, this review report makes relatively few formal findings and recommendations. The bulk of this review, like the previous review, consists of observations and suggestions that are intended to provide the FFRDC team members with guidance and assistance—should they decide to take it—in developing their final report. In general, the committee intends for the suggestions to provide useful guidance for the FFRDC in the next phase of its analysis and for the recommendations to be actions that the FFRDC should definitely carry out to meet the congressional

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¹ According to DOE’s Radioactive Waste Manual, low-activity waste means the waste that remains after as much of the radionuclides as technically and economically practicable have been removed from the tank waste, and that when immobilized in waste forms, may be disposed as low level waste in a near surface facility, as long as the waste meets criteria in the Waste Incidental to Reprocessing determination. Supplemental treatment refers to processing of the low-activity waste that is excess to that portion to be treated as part of the WTP. See Chapter 1 for more details and Chapter 4 on details about the waste classification and Waste Incidental to Reprocessing determination.

mandate in Sec. 3134. This review also has some conclusions to show what the FFRDC needs to have in its final report to meet the congressional mandate.

THE NEED FOR A COMPARATIVE ANALYSIS

The committee’s fundamental conclusion at this juncture is that the FFRDC’s final report needs to provide a structured comparative analysis that can form the basis for selection among the treatment alternatives. Comparative analysis is the essence of the congressionally mandated task. The committee suggests that a useful final report be fundamentally structured around a common set of factors to guide decision-makers. In particular, the committee suggests that the FFRDC’s final report:

• Give consideration to the sources, consequences, and probabilities of the several types of risks (health, environment, social, and regulatory) posed and avoided by each alternative approach;
• Assess the reliability (the likelihood that it can be made to operate and then continue to produce waste forms of the intended quality, at the expected rate, on a sustained basis) of the technology underlying the approach;
• Estimate the full lifetime costs of approaches, as both present value and timeline estimates; and
• Prioritize the information and analysis for decision-makers by asking some relevant questions:
  • What information will be of most salience to DOE and its stakeholders?
  • What information would be “show-stoppers” or trigger no-go decisions?
  • What information makes little difference to the final decision, either because it is relatively unimportant, or because there is little meaningful difference between the alternatives in that respect?
  • Where do uncertainties overwhelm the results of the analysis?

Cost-Benefit Analysis

To meet the congressional mandate (see Appendix A), the final report is required to provide a cost-benefit analysis. The committee observes that the draft report provides cost-estimation analysis, which is one component, but does not discuss or list the benefits for consideration of each treatment option; thus, the draft report does not provide a cost-benefit analysis. (See Chapter 2 for more details.)

Finding 2-1

The information compiled by the FFRDC team does not guide the reader to the Sec. 3134 factors and criteria that are most likely to distinguish one treatment approach from another. Especially in view of the volume of information (in more than 150 pages of appendixes) and the number of approaches and variations, it will be difficult for DOE and stakeholders to make the most effective use of the report as presently configured, which has all of the “summary” chapters labeled as “To Be Determined.”

Finding 2-2

The FFRDC’s current draft report emphasizes information and analysis concerning the treatment approaches in isolation from each other, making a direct comparison of them difficult for decision-makers. The information presented in the draft report lacks meaningful integration for the purpose of comparison. For example, the approaches to supplemental waste treatment are presented separately and not as a comparative analysis. Because the fundamental purpose of the FFRDC analysis is to form the basis for making choices among alternatives, a direct comparison for each factor will greatly improve the utility of the report for decision-making.

Recommendation 2-1

In order to distinguish one treatment approach from another, in its final report the FFRDC should identify the distinctive aspects of the chosen approaches in a comparative analysis. Moreover, the FFRDC needs to present that information in a manner consistent with cost-benefit analysis practice, adapted to the case where benefits are presented in non-monetized terms.

Recommendation 2-2

The final report should emphasize and describe in detail the most important differences among the alternatives with respect to the decision-relevant attributes, and present the areas of difference in a parallel format that enables ready and accurate comparison for the purposes of the selection of a preferred alternative by the decision-maker.

ANALYSIS OF THE ALTERNATIVE TREATMENT APPROACHES

The FFRDC team presents three primary alternatives, together with variants on each: vitrification, grouting, and steam reforming. As discussed in Review #1, the committee observes that the FFRDC team has appropriately limited its analysis to these three alternatives and key variants. Therefore, as described in Chapter 2, the task for the FFRDC team is to gather the information and provide the analytical results necessary for a decision-maker to distinguish, weigh, and ultimately choose among these particular alternatives. As mentioned above, the draft report has major gaps, especially in the “summary” chapters.

Finding 3-1

As a compilation of information, the FFRDC draft report has collected and documented an impressive amount of material that is relevant to a decision regarding the treatment and disposal of SLAW. Nevertheless, there remain gaps in data and analysis results that have been acknowledged by the FFRDC team that will be required for DOE’s decision-making.

Finding 3-2

The FFRDC’s draft report limits its detailed consideration to three main approaches (vitrification, grout, and steam reforming)—those explicitly identified in Sec. 3134—and variations of those alternatives. The limitation to these three main approaches is justified by the current state of the relevant technologies, and the inclusion of variations takes into account opportunities to improve the effectiveness of each approach and to take advantage of opportunities created by each approach.

Recommendation 3-1

Before finalizing its report, the FFRDC should identify and provide the information and analysis that are critical for a decision by DOE. If it is impossible to gather the necessary information within the time permitted by the authorizing statute, the FFRDC team should clearly identify the gaps and assess their potential impact on the analysis.

Waste Form Performance Following Disposal

A fundamental issue is how well the disposal of the waste forms from the alternatives meets the performance requirements for the disposal sites. Each waste form would have to be understood in enough detail

(including materials description, location of key radionuclides and metals [as listed under the Resource Conservation and Recovery Act (RCRA)] in the waste form, radionuclides’ chemical form, and release mechanisms) such that a decision-maker would know the basis for the performance assessment (PA) in the relevant disposal site. DOE has finished its PA for the Integrated Disposal Facility (IDF) at Hanford, but as of the writing of this review report in mid-September 2018, the PA had not been made publicly available. Nonetheless, during the February 28, 2018, public meeting, the committee received a briefing about the PA and useful data on the inventory of iodine-129 and technetium-99. The PA is based on the assumptions that the LAW would be vitrified and the secondary waste generated from the LAW vitrification process would be grouted.

As discussed in the FFRDC’s draft report, waste acceptance criteria are the primary means to determine if a waste form is acceptable for a disposal site. The FFRDC recognizes that while the waste acceptance criteria have been established for the off-site facility at Waste Control Specialists (WCS) near Andrews, Texas, at this time, there are only draft waste acceptance criteria for the IDF at Hanford, and those draft criteria are only for a vitrified LAW waste form. To make a comparison among the various waste forms for the IDF, the FFRDC proposes on page 27 of its draft report that it will perform an analysis that will include “documentation of the waste form release mechanisms, waste form and disposal site assumptions including configuration, inventory of key contaminants, recharge/infiltration, barrier life, waste form release rate parameters, values, and basis, and modeling/assessment tools employed.” The committee agrees with this analytic approach and suggests that the FFRDC’s final report provide a clear description of this analysis (including assumptions and approximations) for the different waste forms. (See Chapter 3 for more details.)

Costs of Waste Form Processes

In the draft report, the FFRDC discusses that it has selected specific facilities as analogies for the cost estimation for the three treatment approaches and their variants. The analogous facilities are the Defense Waste Processing Facility at Savannah River Site and the WTP’s LAW treatment facility for vitrification, the Saltstone processing at Savannah River Site for grouting, and the Integrated Waste Treatment Unit (IWTU) at Idaho National Laboratory for fluidized bed steam reforming (FBSR). The committee observes that the draft report does not list references for the cost-estimation data and does not provide much detail as to why these analogous facilities were chosen. For example, while the FFRDC acknowledges that the IWTU produces a different mineralized waste form than what would be produced with Hanford waste if FBSR were used, the FFRDC does not discuss other FBSR facilities that might be better analogies or at least mention other facilities it may have considered. Thus, the committee suggests that the FFRDC’s final report provide more details into the rationale for selecting the best analogous facilities for the FFRDC’s cost estimation and provide a list of references to the cost data. The committee also suggests any discussion of uncertainty in the report’s cost estimates address the question of asymmetry in the uncertainty, for example, what percentage error around the base estimate can be expected in the upward and downward direction. In addition, and particularly important, the committee suggests the FFRDC try to identify whether those ranges of uncertainty are larger for some of the options than for others. Doing so would more clearly allow decision-makers to gain insight to the robustness of the individual cost estimates. (See Chapter 3 for more details.)

Regulatory Compliance

For obvious reasons, regulatory compliance is a fundamental requirement for any treatment approach that DOE chooses. An analysis of compliance is also mandated by Sec. 3134, which requires the FFRDC to analyze the compliance of the various treatment approaches “with applicable technical standards associated with and contained in” relevant regulations. (See Appendix A for the list of regulations.) The

committee observes and appreciates that the draft report’s Appendix J has an extensive discussion of regulatory compliance issues and that Appendix H on Disposal Site Considerations and Appendix I on Transportation Considerations include discussions of relevant regulations affecting these issues.

As mentioned above, based on the outline in pages 27 and 28 of its draft report, the FFRDC proposes to perform an analysis of the various waste forms for the IDF. In order to have meaningful comparisons, it is important that similar degrees of conservatism in data and assumptions be used in these comparison analyses. It is also important in the FFRDC’s final report to describe and discuss the conceptual models and supporting data underpinning the treatment of barriers. The committee also suggests that in the FFRDC’s assessment of alternatives that require transportation of nuclear wastes through multiple states, the team consider concerns of potential opposition of local stakeholders along the transportation routes. (See Chapter 3 for more details.)

Finding 3-3

The regulatory environment for the Hanford tank waste is complex and contested. While the committee does not express an opinion on the correct legal interpretations and policy choices, especially with respect to the “as good as glass” issue, it finds that contested regulatory standards represent a significant program risk to any approach.

Recommendation 3-2

The FFRDC report should define to the extent possible the contested regulatory issues with regard to each approach it considers, and describe to the extent possible the impact of the likely outcomes on the choice of approach and program schedule.

ADDITIONAL PROCESSES AFFECTING THE ALTERNATIVE TREATMENT APPROACHES

Among the challenges for the FFRDC team is that the alternative treatment technologies or approaches for SLAW interface with an existing and planned system that begins with waste in tanks that is itself characterized by numerous uncertainties, and ends with a number of different disposal configurations and locations. The system in which the treatment technology is embedded impacts the choice of technology, and at the same time the choice of technology determines the characteristics and performance requirements of the system. Consideration of the alternative SLAW approaches in isolation from the systems in which they would operate could lead to poor decisions and is almost certain to miss opportunities to adjust other aspects of the SLAW and the system to achieve a faster, safer, more reliable, and less expensive tank remediation. (See Chapter 4 for more details about the specific additional processes that affect the alternative treatment approaches.)

Finding 4-1

It is reasonable to bound the FFRDC’s scope by having it begin with a pre-treated feed stream from the Waste Treatment and Immobilization Plant’s pre-treatment plant or the Low-Activity Waste Pretreatment System because it is impractical to re-invent the numerous system-wide studies of the Hanford tank waste situation. However, it is important to recognize that some changes external to the FFRDC’s scope could have important downstream impacts on SLAW that are essential to understand when deciding on the preferred SLAW approach.

Recommendation 4-1

The FFRDC report should consider the impact of these four processes—pre-treatment, off-gas treatment, secondary waste generation treatment, and load leveling and waste blending—on the treatment rate, reliability, performance of secondary waste following disposal, and cost of alternative approaches to SLAW treatment.

THE ANALYTIC HIERARCHY PROCESS AND EXPERT ELICITATION

The Analytic Hierarchy Process (AHP) is a well-known process to help decision-makers create a structured numerical framework reflecting their objectives in choosing an option from among several where the choice involves trade-offs among multiple attributes or “criteria.” The hallmark of AHP is that once the structuring steps are completed, AHP guides each decision-maker through a sequence of one-on-one comparisons of the criteria, eliciting from the decision-maker what he or she feels is the relative importance of each criterion in maximizing the defined objective. Once all possible pairwise ratings are completed, the AHP software computes a set of relative weights that it will apply to the scores on each criterion (which are assigned in the following step of the process) to produce a rank-ordering of the decision options in terms of how well they meet the overall objective for the decision. Importantly, these weights—and the resulting rank-ordering—necessarily reflect the preferences of the decision-maker. The expressed purpose of the FFRDC’s expert elicitation, consistent with use of AHP methodology, was to identify the specific treatment and disposal options to be considered, and to establish a ranking of these options based on consideration of multiple different attributes.

The question of concern to this committee’s review is whether AHP is a useful tool for responding to the requirements of Sec. 3134. On that question, the critical point is that the AHP method is intended for use by the decision-makers themselves, perhaps with supporting input from technical experts, to rank alternatives to support making a specific choice among them. The role of the FFRDC team is not to choose or recommend an option but only to provide decision-relevant information about the costs, benefits, risks, and uncertainties of the options. However, in its use of AHP, the FFRDC team has had to incorporate its own set of preferences into the process. (See Chapter 5 for more details.)

Finding 5-1

The FFRDC’s role in the Sec. 3134 congressional mandate is to produce a comparison of the costs, benefits, and risk trade-offs necessary to support a well-informed public policy decision-making process by DOE and others, but the implementation of the AHP did not lead to a defensible ranking of the alternatives.

Recommendation 5-1

In its final report, the FFRDC should focus on the decision factors identified by Sec. 3134 as the basis for its analysis. The remainder of the main body of the final report should be structured so as to permit direct comparison of the approaches (including SLAW treatment and pre-treatment variants) according to direct estimation of what is known about each of those factors.

Recommendation 5-2

While ranking alternative approaches according to individual criteria, as the FFRDC has done in the draft report, may inform the decision-maker, the FFRDC’s final report should refrain from attempting or presenting a single or unified ranking of alternatives, or assigning priorities or weights to the criteria—and thus avoid supplanting the role of the decision-maker.