Summary

Section 3134 of the National Defense Authorization Act for Fiscal Year 2017 (P.L. 114-328) 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. Section 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 first of four to be issued by the National Academies to address the congressional mandate, focuses on study charges 1-3 in the Statement of Task. The committee’s comments in this review report are based on about 70 pages of draft working documents made publicly available on February 14, 2018; a set of about 140 slides produced by the FFRDC and presented at the public meeting on February 28-March 1, 2018, in Richland, Washington; and public presentations at that meeting and presentations at the first public meeting on December 12-13, 2017, in Washington, DC.

Crucially, the FFRDC’s analysis is at an early stage, and much additional work remains to be done. Accordingly, this review provides the committee’s observations about the publicly available work, as of March 1, 2018, and suggestions for the forthcoming analytic report by the FFRDC.² The committee’s overarching task is to provide a concurrent, independent peer review of the ongoing FFRDC’s 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 design, construction, and operations. Indeed, the committee understands from the first public presentation by the FFRDC on December 12, 2017, that 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 to one another.

RISK ASSESSMENT METHODOLOGIES

The FFRDC plans to use three types of risk assessment techniques in its analysis: probabilistic risk assessment (PRA), semi-quantitative expert elicitation, and qualitative hazards assessment. The committee suggests that the FFRDC specify and explain in its forthcoming report what type of PRA will be used, the parts of the supplemental LAW (SLAW) system to which it will be applied, and the basis for not applying it to other parts of the SLAW system, as well as the basis for selecting the risk analysis techniques applied

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¹ According to DOE, 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. Supplemental treatment refers to processing of the low-activity waste that is excess to that portion to be treated as part of the Waste Treatment and Immobilization Plant (WTP). See Chapter 1 for more details.

² Because the FFRDC’s analysis is at such an early phase, the committee’s review is necessarily preliminary and incomplete. The committee uses the terms observations and suggestions, rather than the more familiar consensus-study terms findings and recommendations to recognize the preliminary nature of this review.

to other parts of this system. It will also be useful for the FFRDC to discuss which risks can be quantified and which can be analyzed using qualitative assessments, e.g., legal and regulatory risks. The FFRDC has stated that it will mostly use expert elicitation to help assess the supplemental treatment options and will have its team members serve as the elicitation’s subject matter experts; however, the FFRDC has not fully described how it will carry out this elicitation. The committee also suggests that the FFRDC consider a complete set of risks associated with shipping waste forms off the Hanford Site. See Chapter 2 for additional details.

COST ESTIMATION

The core reference document for the FFRDC’s cost-estimation analysis is the latest revision (Revision 8) of the River Protection Project System Plan produced by DOE’s Office of River Protection in consultation with the Washington State Department of Ecology (this document is often referred to as System Plan 8). The cost estimation figures based on System Plan 8 are not detailed or precise enough for decision-making. The committee notes that the FFRDC plans to use cost data from analogous treatment facilities at other sites, as well as data from System Plan 8. The committee suggests that the FFRDC team in its forthcoming analysis discuss how order of magnitude (which is significantly uncertain) cost estimates could be useful to decision-makers. See Chapter 2 for additional details.

SCHEDULE ASSESSMENTS

Schedule assessments can involve the examination of timelines for completing tasks such as processing and treatment of SLAW waste streams. The committee suggests that the FFRDC’s forthcoming analysis examine the important interrelationships among technical and schedule risks as well as safety and costs. In particular, a better understanding of scheduling risks could include considering an incremental approach that would have the SLAW treatment choice be made after the Waste Treatment and Immobilization Plant (WTP) at Hanford is operational, keeping in mind the WTP’s start date, in order to take advantage of the additional knowledge gained from experience with the actual operation of the waste transport, pre-treatment, and treatment technologies and facilities. It is also worth considering performance of a sensitivity analysis of the likely downtimes or failures of essential equipment as well as of the potential for using modular equipment that could be switched out in the event of equipment breakdown. See Chapter 2 for additional details.

REGULATORY COMPLIANCE ASSESSMENT

Significant disagreements about fundamental aspects of the regulatory environment could render any SLAW treatment options highly uncertain. One important uncertainty is departure from the widely assumed use of vitrification for producing glass waste forms unless the alternatives are shown to be “as good as glass,” a standard that is widely repeated but not formally adopted or defined by state or federal governments. As to the disposal site, there also appears to be a time-of-compliance disagreement between DOE’s Order 435.1, which has a compliance period of 1,000 years, and the Washington State Department of Ecology’s assessment, which focuses on the time when the calculated dose will reach its peak—as much as several thousand years after disposal depending on the waste form. Resolution of this disagreement might affect the selection of the final treatment technology. It is unclear whether there are parallel differences concerning the point of compliance.

The committee suggests that the FFRDC’s analysis discuss what would be required for the non-vitrified waste forms being assessed to be considered “as good as glass” in the context of the current state of technology for waste forms other than glass from a technical and human health risk perspective. Concerning stakeholders’ acceptance of non-vitrified waste forms, the committee recognizes that an additional evaluation of the applicable regulations that would be used to determine legal compliance of alternative

waste forms would be useful. The committee also suggests that the FFRDC’s analysis discuss how consideration of pre-treatment processing alternatives to remove radionuclides such as technetium-99 and iodine-129 could expand on-site and off-site disposal options, taking into account compliance with applicable laws and regulations, and the extent to which various treatment (immobilization) options affect the need for pretreatment to remove key radionuclides. See Chapter 2 for additional details.

WASTE CONDITIONING AND SUPPLEMENTAL TREATMENT APPROACHES

The FFRDC’s draft working documents and presentations discuss the three primary supplemental treatment technologies: vitrification, grouting, and fluidized bed steam reforming. The FFRDC has not identified any other primary SLAW treatment technology, and the committee is not yet aware of any other primary technologies that are sufficiently developed or likely of success to warrant detailed analysis. The committee offers the following observations about these three technologies:

• Vitrification, while a known technology, is still technologically challenging and thus technologically risky, especially when applied to complex and heterogeneous chemical mixtures and to the large scale of waste processing at Hanford, both of which exceed parameters encountered elsewhere.
• The grouting treatment approach would require high-quality constituent materials that could become less available or more expensive at the time when the SLAW treatment plant would become operational (in several years) and during the decades’ long duration of operations.
• In the fluidized bed steam reforming process (FBSR), the Integrated Waste Treatment Unit at Idaho National Laboratory may not be a very useful model for steam reforming at Hanford because it has yet to work at scale and has experienced several technical and management problems since 2012, though as the FFRDC notes, experience at some commercial facilities might be applicable. Also, the source of high-quality coal for the coking process in FBSR might pose a supply chain concern.

The committee suggests that the FFRDC include its assessment of the potential problems and technical challenges of each of these treatment technologies as well as the potential barriers to acceptance of any of these technologies and the resulting waste forms for disposal sites under consideration.

The FFRDC’s working documents and presentations indicate that there are opportunities for better SLAW treatment performance by making certain upstream flowsheet changes for conditioning (pretreatment) of SLAW. The committee suggests that it would be useful for the FFRDC to identify promising upstream technologies or processes and use them to perform a sensitivity analysis on their effect on treatment flowsheets. Consideration can be given to removal of particular radionuclides of concern, such as technetium-99, iodine-129, and strontium-90, as well as methods of blending tank wastes. The analysis would benefit by having clear explanations of the reasons for such pre-treatment, for example, to remove certain radionuclides and other hazardous chemicals to meet waste acceptance criteria at certain disposal sites or to produce a releasable effluent. The committee also suggests that the team could usefully consider, at least briefly, whether certain combinations of immobilization technologies could confer particular advantages. See Chapter 3 for more details.

KEY INFORMATION AND DATA SOURCES BEING USED

The FFRDC has stated that its analysis will rely substantially on the One System Integrated Flowsheet and System Plan 8. This flowsheet and plan have numerous assumptions and uncertainties. The committee suggests that the FFRDC explicitly identify, discuss, and document the underlying assumptions that could impact its analysis. The committee also suggests that the team, if it has not yet done so, obtains and analyzes credible existing studies and data on long-term waste form performance to inform analysis of the “as good as glass” issue. See Chapter 4 for more details.

Comments Received from Stakeholders and Interested Members of the Public

The committee appreciates the many informed presentations and comments received from stakeholders and members of the public during its public meetings. A major underlying theme of the comments appears to be safety, especially in safely processing the wastes, protecting the public (including future generations), and protecting the Columbia River and the surrounding environment. Several stakeholder and public commenters noted that, in their view, vitrification is the “agreed-to” treatment option for high-level waste and LAW, and that SLAW treatment should meet the concept of “good as glass,” which has been interpreted in different ways. Some commenters stated that the peoples living on the land and fishing the rivers in the Hanford region for several thousand years do not look at timelines in the same way as DOE and emphasized that their priority is safe access to their traditional foods. See Chapter 5 for more details.

General Comments

The committee suggests that the FFRDC’s forthcoming analytic report include:

• An accessible organizational structure of the analytic approach that presents clear choices and their consequences to decision-makers, with the recognition that the FFRDC will not select a preferred supplemental treatment option.
• A complete and consistent set of supplemental treatment alternatives specifying clearly whether just the major three supplemental treatment approaches are being assessed or whether there are any variations on these three to consider, including the processing, transportation, and disposal options in each alternative. Likewise, the committee suggests that the FFRDC consider identifying and describing opportunities to improve the performance, cost, and rate of implementation of the alternatives through pre-treatment to disposal, even if some are strictly speaking outside of the scope of the SLAW facility.
• Lines of inquiry to include, among other issues:
  • Safety (including nuclear safety, chemical safety, and physical safety of workers and the public)
  • Technical readiness of each option
  • Waste form performance for each option
  • Secondary wastes and effluents produced for each option
  • Cost of each option
  • Schedule of each option
  • Overall regulatory compliance
• A characterization of uncertainties for each line of inquiry.
• The use of appropriate assessment methodologies implemented using best practices for the comparisons within the lines of inquiry.