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 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 Sec. 3134 is provided in Appendix C, and the Statement of Task for the National Academies review is provided in Appendix D.

This review report, the final of four to be issued by the National Academies to address the congressional mandate, focuses on the Statement of Task’s study charge for the committee to provide a summary of public comments on the third committee review report, which was published on August 15, 2019, and the committee’s views, if any, on these comments and whether they change any of the findings or recommendations in the third review report. The comment period began on August 15, 2019, and concluded on November 20, 2019. According to Sec. 3134, the comment period was to last for a minimum of 60 days. The period was extended to allow stakeholders and members of the public to submit comments in light of additional information that was received at the final public meeting on October 31, 2019, and the FFRDC final report, which is dated October 18, 2019. Notably, during this final phase of the study, the committee is neither required nor expected to perform a peer review of that final report.

As “ground rules” for this final review, first, the committee has considered all comments received during the comment period from August 15, 2019, to November 20, 2019; for the list of commenters and summaries of the comments, see Appendix E. Second, for potential revisions to the committee’s Review #3, the committee decided to revise where a correction is needed or where there is either an objective error or omission. (For completeness and as an aid to readers, Appendix A reproduces the essential parts of Review #3, including findings and recommendations as well as the committee’s review of the FFRDC final draft report and the committee’s advice for decision-makers.) Third, this final review acknowledges significant new information, which became available only after the committee’s Review #3 was published and which the committee considered in deciding whether to change or modify any of its findings and recommendations in Review #3. The new information involves (a) the performance assessment for the Integrated Disposal Facility (IDF) at Hanford was made available leading to an additional recommendation (Recommendation 5-1) on the drinking water standard; and (b) the final FFRDC report was published, and the committee received comments from the FFRDC on Review #3. Fourth, the committee does not respond in a one-to-one manner to each comment received. Instead, the committee has identified concepts and themes among these comments and has responded with observations on selected comment themes.

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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 by vitrification in the Waste Treatment and Immobilization Plant.

As a reminder, throughout this process the committee was neither charged to evaluate the supplemental treatment approaches nor to recommend any particular approach. Equally important, the committee notes that several important questions for the Hanford site were not in the scope of the FFRDC’s analysis (and thus not in the scope of the committee’s review), in particular, tank waste management, high-level waste (HLW) processing and treatment, treatment and disposal of LAW not considered SLAW, the proper definition or interpretation of high-level waste or other legal agreements or requirements, and the Waste Treatment and Immobilization Plant’s (WTP’s) design, construction, and operations.

Indeed, the FFRDC, quite properly, does not identify a preferred option for supplemental treatment in its report, but instead it separately evaluates the treatment alternatives against the baseline, as well as against one another, for a number of factors important to selecting a preferred alternative. The de facto baseline is vitrification of the LAW in the supplemental LAW (SLAW) treatment facility because it is the current expectation of many stakeholders and a similar facility (the WTP) is currently under construction to be followed by disposal of the resulting wastes in the IDF at Hanford. The FFRDC’s task is to provide data and analysis to enable DOE, with congressional oversight, to decide whether to use vitrification, grouting, fluidized bed steam reforming (FBSR), or other treatment approaches to treat the SLAW by converting it into a waste form for disposal.

Importantly, the committee notes that the evaluations of treatment options for the SLAW include more than just the solidification of the liquid LAW. The objective of the SLAW treatment is to ensure that the solidified wastes can be permanently disposed of in a near-surface land disposal site. Because these sites have “waste acceptance criteria,” additional pre-treatment processing is sometimes required so that the final SLAW form or forms can be accepted for disposal. Additionally, the primary treatment and pre-treatment processes produce “secondary wastes” that also need to be disposed of in a near-surface disposal site. It is this entire SLAW process, from pre-treatment through treatment to disposal, which the FFRDC evaluates and compares.

In addition to the three primary treatment options, the FFRDC also identified two near-surface land disposal options to analyze and compare. The existing IDF located at Hanford is considered as the “baseline” LAW disposal facility, again, because it is the current expectation (and has, in fact, been constructed). In this baseline option, the liquid LAW (including SLAW) would be solidified using vitrification, and the secondary waste would be grouted. While both types of waste are slated to be disposed at the IDF, the Washington State Department of Ecology has yet to approve waste acceptance criteria that would allow for the disposal of grouted secondary waste or even the primary vitrified LAW in the IDF. The second disposal site analyzed is operated by Waste Control Specialists (WCS), and located near Andrews, Texas. WCS is situated in a semi-arid and sparsely populated region of western Texas, and it has become an active commercial low-level waste disposal facility in recent years. It is also designated as a Federal Waste Disposal Facility. The FFRDC report describes the differing, and less restrictive, waste acceptance criteria for WCS as compared with what is anticipated for the IDF, and the effect that using the WCS site would have on the SLAW treatment. The FFRDC also mentions the possibility of disposal at the EnergySolutions site near Clive, Utah, and estimates that this site would require removal of almost all of the strontium-90 from the waste stream to meet its Class A low-level waste acceptance criteria.

Using the criteria specified in Sec. 3134, including risks, benefits, costs, schedules, regulatory compliance, and obstacles to implementation, the FFRDC in its report analyzed five alternatives for treating the primary SLAW: (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, and (5) FBSR for disposal at the WCS site. (Because vitrification is already the expectation for the on-site IDF, there is no reason to consider WCS for vitrified waste.) The vitrification option would result in significant amounts of secondary waste, which, as mentioned above, would be grouted and is proposed to be disposed at the IDF, although the FFRDC also considers the possibility of disposal of this waste at WCS.

The FFRDC in its report estimated that:

• The vitrification technology would take 10 to 15 years to implement and would cost $20 billion to $36 billion.

• The grouting technology would take 8 to 13 years to implement and would cost $2 billion to $8 billion.
• The fluidized bed steam reforming technology would take 10 to 15 years to implement and would cost $6 billion to $17 billion.

The cost estimates are based on technologies that, for the most part, have not yet been fully developed or deployed with Hanford’s uniquely voluminous and heterogeneous tank wastes, and are based on costs from similar technologies, as well as assuming ideal funding conditions (i.e., sustained funding without caps) and no redirection during a multi-year effort. Thus, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, and are unlikely to be much lower. The FFRDC team also concluded that a SLAW treatment and disposal option that meets formal regulatory requirements for disposal can be developed using any of the three treatment technologies evaluated. In addition, the FFRDC report notes that “the required time for construction and startup require an immediate start to allow completion by the required startup date” for some treatment alternatives, because DOE’s current plan is a target date of 2034 for the SLAW treatment to begin (which is essentially the same time as the pre-treatment and HLW vitrification facilities in the WTP are scheduled to begin operations). Recent news reports suggest that this target date may slip by at least a few years (Cary, 2019).

The FFRDC and the committee have gone through multiple iterations of draft FFRDC analysis reports and committee review reports, with both formal and informal comments and responses. The committee finds that the FFRDC has been responsive to most comments, and the most recent FFRDC report, published on October 18, 2019, and stated as being the last while labelled as “predecisional,” has improved very considerably over its predecessors in focus, responsiveness to the congressional mandate, and technical analysis. As detailed in the following Findings and Recommendations, the committee believes that the FFRDC advances the overall understanding of the waste treatment options for SLAW by providing the basis for the kinds of detailed technical studies that would be required for reaching a final decision on the treatment and disposal of SLAW. Based on the committee’s review of comments received during the comment period and the new information received (specifically the IDF’s Performance Assessment [PA]) during this period, the committee has, for the most part, not changed its findings and recommendations from Review #3, which are reproduced here, but the committee notes that it has made additions to Recommendations 1-1 and 2-1. In addition, the committee has a new recommendation in this review report as the committee discusses in Chapter 2 and states in the final section of the Summary.

USING THE FFRDC REPORT

Overall Assessment

Finding 1-1

The purpose of the committee’s review is to advise whether DOE, Congress, regulators, and other stakeholders can rely on the FFRDC report to evaluate and decide on a treatment approach for the SLAW. The committee finds that, in its current iteration, the FFRDC’s analysis:

1. When taken alone, does not yet provide a complete technical basis needed to support a final decision on a treatment approach;
2. Does not yet clearly lay out a framework of decisions to be made among treatment technologies, waste forms, and disposal locations; but
3. Can form the basis for further work as described below in the committee’s findings and recommendations.

Analysis of Costs, Benefits, and Risks

Finding 2-1

The cost estimates in the FFRDC report are based on technologies that, for the most part, have not yet been fully developed, tested, or deployed for Hanford’s particular, and particularly complex, tank wastes, and instead use costs from similar technologies. As a result, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, but are unlikely to be much lower.

Finding 2-2

The cost estimates in the FFRDC report are based on continuing funding at and beyond current levels to optimize the waste treatment technologies and speed of progress. These involve very large annual appropriations, which are inevitably uncertain over the planned decades of activity, especially because current planning assumptions anticipate a two- or three-fold increase in expenditures at certain points in the SLAW treatment process. This, too, introduces the possibility that funding shortfalls will lead to longer schedules, increased total costs, and higher chances of additional tank leaks or structural failures, which will themselves increase costs as well as health and environmental risks.

Finding 2-3

The report’s analysis of costs does not enable the reader to analyze key trade-offs among specific alternatives or variations of major alternatives.

Disposal Risk Assessment

Finding 3-1

Assessment of waste form performance would have to include consideration of the characteristics of the disposal sites and the transport pathways to receptors over relevant periods of time, as well as be based on the inherent characteristics of the waste form.

Finding 3-2²

The committee did not have access to the 2017 IDF PA that has been prepared by DOE or to the Performance Evaluation (PE) data and analysis prepared by the FFRDC. Therefore, it was impossible for the committee to critically review the differences in the performance of the three waste forms and their associated disposal systems over time. Additionally, the technical bases for waste degradation models and mechanisms used in the PE analyses for the IDF by the FFRDC team are not well documented and justified.

Finding 3-3³

Without the proper supporting documentation for the FFRDC’s PE, or the IDF PA on which it was based, the committee is unable to assess the potential significance of mobile, long-lived fission products such as iodine-129, technetium-99, and other long-lived radionuclides (possibly selenium-79 and others). It would have been useful for the FFRDC to include the human health risk estimates (dose) over time for

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² The committee notes that subsequent to publication of Review #3, it received access to the PA. See the discussion in Chapter 2 of this review report for the committee’s observations about relevant aspects of the PA and about what was available in the FFRDC final report on the PE.

³ See the previous footnote about the committee’s views on the PA and the PE as discussed in Chapter 2.

all of the long-lived radionuclides that are listed in Table F-2 of their report, not just iodine-129 and technetium-99.

Finding 3-4

The FFRDC report gives little consideration in its analysis to the environmental, health, and safety consequences of hastening or further delaying remediation of the Hanford waste storage tanks, which is related to the probability that additional tank leaks or structural failures will occur over the long period of time expected for the removal and treatment of the waste in the tanks.

Pre-Treatment to Remove Iodine-129 and Technetium-99

Finding 4-1

The FFRDC performed an analysis of whether removal of iodine-129 and technetium-99 was needed to comply with the disposal waste acceptance criteria, and examined the status of technologies for removing these radionuclides from the SLAW feed stream, but the FFRDC report does not respond fully to the congressional direction (in Sec. 3134) because the report does not address immobilization of the iodine-129 and technetium-99 recovered from the LAW as part of the separate high-level glass waste form to be produced in the WTP.

Other Observations

Finding 5-1

The report makes little use of the experience with grouting and other technologies at other DOE sites and commercial operations. While there are unquestionably meaningful differences among the waste forms, technologies, and disposal environments as compared to Hanford, the extensive experience gained at Savannah River Site, in particular, is an invaluable source of insight.

Finding 5-2

The committee was repeatedly told that the selection and implementation of an approach to treat tank waste would be hampered by the insistence by the State of Washington and some other stakeholders that any approach other than vitrification must be “as good as glass.” The term “as good as glass” is not defined in law, regulation, or agreement, and it is only tentatively defined by its advocates. The analysis in, and the public presentations of, the draft FFRDC reports offer a follow-on opportunity for DOE to engage with its regulators and stakeholders to identify performance standards based on existing regulatory requirements for waste form disposal and to pursue a holistic approach to selecting a treatment technology.

Comparisons

Finding 6-1

Over multiple iterations, the FFRDC report has increasingly enabled side-by-side comparisons among the SLAW treatment approaches, exemplified by the table of alternatives and criteria. It remains difficult, however, for the reader to see comparisons and trade-offs in the supporting narrative.

The FFRDC Report’s Steps Forward

Finding 7-1

The report represents useful steps forward by:

1. Confirming that versions of vitrification, grouting, and steam reforming are treatment technologies that merit further consideration for the SLAW;
2. Establishing the likelihood that vitrification, grouting, or steam reforming are capable of meeting existing or expected regulatory standards for near-surface disposal albeit with varying amounts of pre-treatment being required;
3. Highlighting the important contribution of the iodine-129 in the secondary waste streams disposed at the IDF to the total estimated radiation dose rate to the receptors;
4. Underscoring the regulatory and acceptance uncertainties regarding approaches other than vitrification technology for processing the SLAW; and
5. Opening the door to serious consideration of other disposal locations, specifically the WCS facility near Andrews, Texas, and possibly the EnergySolutions facility near Clive, Utah.

Use the FFRDC Report as a Pilot or Scoping Study

Recommendation 1-1

The committee recommends that the “Preliminary Draft” FFRDC report reviewed by the committee (that is, the document dated April 5, 2019) be accepted as a pilot or scoping study for a full comparative analysis of the SLAW treatment alternatives, including:

• Vitrification, grouting, and steam reforming as treatments for the SLAW;
• Pre-treatment to remove iodine-129, technetium-99, and other long-lived radionuclides (e.g., selenium-79) to ensure that regulations are met or reduce cost, and pre-treatment to assure that the waste product meets land disposal requirements;
• Pre-treatment of strontium-90, if it is not removed during the cesium-137 pre-treatment process; and
• Disposal at the IDF, WCS, and (possibly) the EnergySolutions facility.

The draft report should either be substantially revised and supplemented (though the committee understands that the FFRDC team’s funding may not permit this), or be followed by a more comprehensive analysis effort and associated decisional document, which needs to involve the decision-makers or their representatives. This comprehensive analysis should adopt a total systems approach (one that includes addressing relevant externalities to SLAW that were outside the FFRDC’s scope) to provide a substantially complete basis for decision-making.

Organize the Report or Decisional Document Around Four Interrelated Areas

Recommendation 2-1

The final FFRDC report or follow-on decisional document should include technical data and analyses to provide the basis for addressing four interrelated areas, as follows:

• DOE’s proposed reinterpretation of the definition of HLW waste could change the SLAW size and performance requirements by altering the feed volume and composition depending on how the reinterpretation is implemented;
• Thorough consideration of the experience at other DOE sites (e.g., Savannah River Site) and relevant commercial facilities; and
• Outcomes of DOE’s proposed Test Bed Initiative, the second phase of which would have involved (and perhaps still could involve) grout treatment of 2,000 gallons of LAW and shipment to WCS (the first phase involved a proof of concept treatment of 3 gallons of LAW that was sent to WCS and was completed in December 2017). The future of the second phase of the Initiative is now in doubt due to DOE’s withdrawal in late May 2019 of the state permit application.

Need Direct Comparisons of Alternatives to Aid Decision-Making

Recommendation 3-1

The analysis in the final FFRDC report and/or a comprehensive follow-on decisional document needs to adopt a structure throughout that enables the decision-maker to make direct comparisons of alternatives concerning the criteria that are relevant to the decision and which most clearly differentiate the alternatives.

Consideration of Parallel Approaches

Recommendation 4-1

The FFRDC report could also provide the springboard for serious consideration of adopting an approach of multiple, parallel, and smaller scale technologies, which would have the potential for:

1. Faster startup to reduce risks from tank leaks or structural failures if adequate funding is available to support parallel approaches;
2. Resilience through redundancy (like the parallel uranium enrichment and plutonium separation methods during the Manhattan Project);
3. Taking positive advantage of the unavoidably long remediation duration to improve existing technologies and adopt new ones; and
4. Potentially lower overall cost and program risk by creating the ability to move more quickly from less successful to more successful technologies, with less stranded cost in the form of large capital facilities that are inefficient or shuttered before the end of their planned lifetime.

CONCLUDING OBSERVATIONS

Based on its review of relevant aspects of the performance assessment of the IDF, the committee notes that the U.S. Environmental Protection Agency (EPA) drinking water standard (DWS) for iodine-129 and perhaps technetium-99 appears to be a key consideration in future decisions concerning the need for pretreatment to lower the concentrations of these two long-lived radionuclides and preferences for a particular waste form. This standard is based on radiation protection approaches dating from the 1950s and is no longer currently recommended by radiation protection authorities.

Recommendation 5-1

It would behoove DOE to consult with its regulators (particularly EPA and Washington State Department of Ecology) to determine whether risk-informing the current drinking water standard in terms of its

underlying dosimetry and the assumed point-of-compliance is appropriate for application to SLAW disposal, or whether a more up-to-date standard for drinking water should be adopted. In view of the extent to which disposal decisions are driven by this standard, such a re-assessment would be well worth the effort.

The committee concludes the Summary with noting key points from the stakeholder’s and members of the public’s comments. Many commenters expressed concern about placing long-lived radionuclides such as iodine-129 and technetium-99 in non-vitrified waste forms for near-surface disposal in the IDF at Hanford. A major driver of this concern is the potential hazard to drinking water and the river system, especially the Columbia River. Related to the concern about durability and waste retention of non-vitrified forms is the strongly held view among many commenters that vitrified waste forms would provide more protection for waste disposed at Hanford and is encapsulated in the saying “as good as glass.” On the other hand, there is widespread interest in the potential for out-of-state disposal of non-vitrified waste forms. Finally, representatives of tribal nations and many members of the concerned and engaged public have clearly stated that decision-makers need to consider the entire ecosystem at Hanford and the potential for major climatic changes, massive flooding, and seismic activity, which might adversely affect waste disposal at Hanford.