Appendix A

Major Parts of Review of the Final Draft Analysis of Supplemental Treatment Approaches of Low-Activity Waste at the Hanford Nuclear Reservation: Review #3

CONTENTS

SUMMARY

1 CONTEXT AND SETTING

Proposed Treatment Plan and Congressional Mandate to Analyze and Review the Analysis of Supplemental Treatment Approaches

Study Process

Brief Historical Context of Tank Waste Treatment Approaches

Review Report Organization

2 THE COMMITTEE’S TECHNICAL REVIEW OF THE FFRDC’S FINAL DRAFT ANALYSIS

General Observations

Methods Used to Assess Risks, Costs, Benefits, Schedule, and Regulatory Compliance and How They Were Implemented

Waste Conditioning and Supplemental Pre-Treatment Approaches Considered in the Assessments, Including Any Approaches Not Identified by Congress

Other Key Information and Data Used in the Assessments

Presentation of Assessment Results

The Committee’s Findings

3 THE COMMITTEE’S ASSESSMENT OF THE USEFULNESS FOR DECISION-MAKERS OF THE FFRDC’S FINAL DRAFT ANALYSIS

Considerations for Decision-Makers

The Committee’s Recommendations

REFERENCES

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 third 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 an “overall assessment.” The committee’s overall assessment is divided into two parts: a technical review (based on the elements in the committee’s Statement of Task) of the FFRDC final draft analysis and a “guide” of the report to aid decision-makers. The committee’s comments in this review report are based on the FFRDC’s final draft report of 278 pages, dated April 5, 2019, and a set of 43 slides produced by the FFRDC and presented at the public meeting on May 16, 2019, in Kennewick, Washington, as well as FFRDC team members’ and others’ public presentations (see Appendix E) at that meeting.

This review report is the final opportunity for the committee to review the FFRDC’s work. It is anticipated that the FFRDC will produce a final report for publication in fall 2019 and that the FFRDC will make use of the committee’s review report in doing so. After publication of the committee’s review report, stakeholders and the interested public will have an opportunity to offer comments on that report and the FFRDC’s final draft report for a period of at least 60 days. The committee’s final task will be to produce a fourth review report that will provide a summary of public comments on the third committee review report and the committee’s views, if any, on these comments and whether they change any of the findings or recommendations in this, the third, review report.

The committee’s overarching task has been to provide a concurrent, independent peer review of the ongoing FFRDC analysis. The committee is neither charged to evaluate the supplemental treatment approaches nor recommend any particular approach. 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 does not identify a preferred option for supplemental treatment, but instead in its report, 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

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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.

construction to be followed by disposal of the resulting wastes in the Integrated Disposal Facility (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 another treatment approach 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 waste 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 process from pre-treatment through treatment to disposal that 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. 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 of 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 located in an arid and isolated region of western Texas, and it has become an active commercial low-level waste disposal facility in recent years, as well as being 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. The vitrification option would result in significant amounts of secondary waste, which, as mentioned above, would be grouted and proposed to be disposed of at the IDF, although the FFRDC also considers the possibility of disposal of this waste at WCS.

The FFRDC in its report concluded 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, and are based on costs from similar technologies, as well as assuming ideal funding conditions (i.e., no funding caps) and no redirection during a multi-year effort. Thus, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, but are unlikely to be much lower. The FFRDC team also concluded that a SLAW treatment and disposal option that meets regulatory requirements for disposal can be developed using any of the three treatment technologies evaluated. In addition, the FFRDC report (on p. 22) notes that for some treatment alternatives, “the required time for construction and startup require an immediate start to allow completion by the required startup date” because DOE’s current plan is a target date of 2034 for the SLAW treatment to begin in combination with the WTP.

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 generally been responsive to comments, and the most recent FFRDC report has improved considerably over its predecessors in focus, responsiveness to the congressional mandate, and technical analysis. Furthermore, in offering the suggestions in this review report, the committee recognizes that the FFRDC’s work is planned to end in fall 2019. Thus, the suggested improvements are included to aid the reader in interpreting the contents of the FFRDC report and for potential use in follow-on studies.

Based on the committee’s technical review (see Chapter 2 for details) of the FFRDC’s final draft report and the presentation materials from the May 16, 2019, public meeting, and based on the committee’s consideration of the usefulness of the final draft analysis for decision-makers (see Chapter 3 for details), the committee has reached consensus on the following findings and recommendations.

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 3-2

The committee did not have access to the 2017 IDF Performance Assessment (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 3-3

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 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.

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:

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.

1

Context and Setting

The nation’s biggest and most complex nuclear cleanup challenge is at the Hanford Nuclear Reservation. From 1944, when plutonium production began in the B Reactor during the Manhattan Project, to 1987, when the ninth and last plutonium production reactor was shut down, the Hanford Nuclear Reservation had produced about two-thirds—approximately 67 metric tons—of the nation’s plutonium stockpile for nuclear weapons. The massive scale of the production processes resulted in substantial amounts of radioactive and other hazardous wastes. Presently, 177 underground tanks collectively contain about 211 million liters (about 56 million gallons) of waste (WRPS, 2018). The chemically complex and diverse waste is difficult to manage and dispose of safely because of several factors. These include the use of three different methods for plutonium extraction from irradiated nuclear fuel, the mixing of wastes among tanks from transfers to optimize tank usage, the prior efforts to neutralize or otherwise alter the waste, the (incomplete) recovery of cesium-137 and strontium-90, which were placed in separately stored capsules, and the addition of materials to the tanks from auxiliary processes (Peterson et al., 2018). 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).

In its first and second review reports, the committee underscored in the introductory chapters the fundamental importance to the tasks of the congressional mandate in Section 3134 (Sec. 3134) of the National Defense Authorization Act of Fiscal Year 2017 (see Appendix C). As in the previous reviews by the committee, this chapter of the review report also provides a brief introduction to the congressional mandate to set the stage for this review and about the study process. In addition, it gives brief historical context about the waste treatment approaches considered or developed since 1989, when the TPA began. This context is important to highlight that past developments continue to influence the present treatment plan for the tank waste.

PROPOSED TREATMENT PLAN AND CONGRESSIONAL MANDATE TO ANALYZE AND REVIEW THE ANALYSIS OF SUPPLEMENTAL TREATMENT APPROACHES

DOE-EM has proposed to retrieve the waste from the tanks to produce two waste streams, high-level waste (HLW) and low-activity waste (LAW), by removing several specific radionuclides that contain 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, 2011b) during the processing of the waste streams in the Waste Treatment and Immobilization Plant (WTP), which is already under construction at Hanford.

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 and perhaps all of the direct (primary) LAW stream, depending on decisions yet to be made. Secondary LAW waste comprised of liquid wastes, off-gas filters, and other internally generated wastes is expected to be grouted, that is, immobilized in a

cementitious waste form. Due to capacity limits in the LAW vitrification facility portion of the WTP, which is also under construction, DOE-EM anticipates that there will be substantial amounts of the LAW that the WTP cannot process 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 consideration has been given to an off-site location such as the Waste Control Specialists (WCS) facility near Andrews, Texas.

DOE-EM has yet to formally select a supplemental treatment approach, though the Department of Ecology and some stakeholders believe that DOE has previously promised to use vitrification. To help with the final selection, Congress directed DOE-EM in Sec. 3134 to contract with a Federally Funded Research and Development Center (FFRDC) to perform analysis on treatment approaches. According to Sec. 3134, the 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 a calcined powder or a monolithic crystalline ceramic waste form.

Sec. 3134 also asks for identification by DOE of additional alternative treatment approaches, if appropriate. At this stage of the study, neither DOE nor the FFRDC has identified additional alternative primary approaches, though the FFRDC has identified some variants of the primary approaches. As discussed in the FFRDC’s final draft report, dated April 5, 2019, the FFRDC team is considering 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. In a previous draft analytic report, the FFRDC had considered nine variants of the three primary treatment alternatives. Also, to implement the five currently identified alternatives, additional waste conditioning (pre-treatment) 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. Notably, Sec. 3134 requires an analysis of “further processing of the low-activity waste to remove long-lived radioactive constituents, particularly technetium-99 and iodine-129, for immobilization with high level waste.”

In parallel to selecting an FFRDC, DOE was directed in Sec. 3134 to contract with the National Academies of Sciences, Engineering, and Medicine (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. The charge to the FFRDC team from Sec. 3134 is in Appendix C. The Statement of Task for the National Academies of Sciences, Engineering, and Medicine’s (the National Academies’) committee is in Appendix D.

The FFRDC team’s task is to provide DOE and Congress with facts and analyses regarding treatment approaches, but not a recommendation concerning a preferred alternative. Likewise, the committee, as peer reviewer, does not offer or imply a recommendation among alternative approaches.

This congressionally mandated study has come about in part due to a 2017 U.S. Government Accountability Office (GAO) report that indicated significant cost savings for the grout treatment approach as compared to vitrification, based on the experience of the Savannah River Site’s (SRS’s) use of grout for about

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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.

4 million gallons (as of the date of that report) of LAW (GAO, 2017). Because the chemical composition of the LAW at the SRS is not as complex as the LAW at Hanford, however, the cost and performance of using grout treatment at Hanford could differ significantly from the cost at the SRS. The GAO report, therefore, recommended:

In its report, GAO noted that “DOE agreed with both recommendations.”

STUDY PROCESS

In this third review report, the committee provides its peer review and discusses its observations of the FFRDC’s final draft report, dated April 5, 2019,² and the FFRDC’s presentations at the public meeting in Kennewick, Washington, on May 16, 2019.³Table 1-1 lists the FFRDC’s presentations from this meeting. The webcast videos of the public meetings are archived and available for viewing.⁴

During the most recent public meeting in Kennewick, Washington, the committee received briefings from some presenters who were not from the team, as listed in Appendix E. In addition, throughout the study, the National Academies has received comments submitted via e-mail and mail, which are available in the Public Access File. Sec. 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, Sec. 3134 highlights the necessity of consultation with the State of Washington and an opportunity for it to comment on the FFRDC’s draft report and the committee’s review of that report. The committee received invited presentations during the second, third, fourth, and most recent sixth public meetings from the Department of Ecology and has considered these presentations in its review.

Table 1-2 shows the current schedule for the FFRDC’s work, the committee’s review, the public meetings, and the briefings to stakeholders. While this schedule is subject to change, it is designed to allow adequate time for the FFRDC and the committee to do their work in the iterative fashion described in the Statement of Task, and for regulators, stakeholders, and the public to provide comments. The next public meeting, in Richland, Washington, is planned for October 31, 2019.

To perform the peer review task, the National Academies formed a committee composed of 13 experts and one technical adviser whose expertise spans the issues relevant for reviewing the FFRDC’s analysis, including risk assessments, cost estimation, cost-benefit analysis, waste processing, supplemental treatment approaches, legal and regulatory requirements, and large scale nuclear construction projects. A majority 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 F contains biographical information about the committee members’ qualifications and experiences. The committee also has found it necessary to perform additional fact finding, for example, by receiving briefings from experts outside the FFRDC team about aspects

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² To access the FFRDC’s final draft report, see http://dels.nas.edu/resources/static-assets/nrsb/miscellaneous/ffrdc2019-4.pdf.

³ For this public meeting’s presentations, see http://dels.nas.edu/Past-Events/Meeting-Supplemental-Treatment/DELS-NRSB-17-02/10052.

⁴ For the first public meeting’s video recording, see https://livestream.com/NASEM/DELS-NRSB; for the second public meeting’s video recording, see http://www.tvworldwide.com/events/nas/180228; for the third public meeting’s video recording, see http://www.tvworldwide.com/events/nas/180723; for the fourth public meeting’s video recording, see http://www.tvworldwide.com/events/nas/181129; for the fifth public meeting’s audio recording (no video was recorded), see http://www.tvworldwide.com/events/nas/190108; and for the sixth public meeting’s video recording, see http://www.tvworldwide.com/events/nas/190516.

of the supplemental pre-treatment, treatment, or analysis approaches. Any information learned by the committee during additional fact-finding will be made available in the study’s Public Access File.⁵

TABLE 1-1 List of the FFRDC’s Presentations, Given on May 16, 2019, in Kennewick, Washington

TABLE 1-2 Study Schedule

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⁵ To request information in the Public Access File for this project, see https://www8.nationalacademies.org/pa/ManageRequest.aspx?key=49905.

The FFRDC team was assigned a very large task in a short period of time, that is, to review a long history and large technical literature on three or more very different treatment technologies and, as the analysis developed, the permanent disposition of waste material in two (or potentially three) very different disposal sites. (As the committee has noted in previous reports, the choice among treatment approaches cannot meaningfully be made without consideration of the disposal environment.) The FFRDC team has, as the committee has also noted, worked very hard to grapple with the task it was assigned. It has gathered a large amount of information, performed analysis on it, and adjusted its approach and presentations in response to comments. Nevertheless, as Chapter 2 of this review demonstrates, there are significant technical limitations to the conclusions that can be drawn from the team’s work, especially regarding the analysis of costs and risks, as well as the uncertainties surrounding the technologies themselves, costs, and several important programmatic risks.

The committee’s review is constrained, it goes without saying, by the Statement of Task, which expressly calls for the committee to “evaluate the technical quality and completeness” of the FFRDC report on the treatment options for the SLAW. This is a double limitation: the committee’s report is to be “technical,” and the committee’s scope (along with the FFRDC’s) is to be on treatment approaches to the SLAW. Neither the FFRDC nor the committee was tasked to offer views on broader policy issues or on the overall system for managing tank waste at Hanford. While one may quite reasonably find such limitations frustrating and sometimes even question-begging, they represent Congress’s laudable effort to obtain a well-informed and reliable technical answer to a particular and important question before it.

BRIEF HISTORICAL CONTEXT OF TANK WASTE TREATMENT APPROACHES

To help explain why the Hanford waste treatment approaches are being considered, this section provides brief historical context about tank waste treatment at Hanford. Under the TPA, since 1989, DOE-EM (which was formed in 1989) has tried and discontinued or substantially modified several different approaches to treat and dispose of Hanford’s tank waste. In 1989, the initial approach was to treat only the waste in the double-shell tanks. The preferred alternative in the 1987 Defense Waste Environmental Impact Statement, the basis for the 1989 plan and for DOE’s 1988 Record of Decision on “Disposal of Hanford Defense High-Level, Transuranic, and Tank Waste,” was to pre-treat the existing and future double-shell tank waste into two fractions with the high-level fraction being processed in the High-Level Waste Vitrification Plant “and disposed of in a geologic repository, and the remaining low-activity fraction grouted and disposed of near-surface in preconstructed lined concrete vaults.” Regarding the single-shell tanks, in the 1988 Record of Decision, DOE, in selecting the preferred alternative, “decided to conduct additional development and evaluation before making decisions on final disposal” (DOE, 1988). The near-surface vaults would have been on-site and would have been covered by a protective barrier; these vaults would also have had a marker system to warn people about the disposal site. The facility would have been called the Hanford Grout Disposal Facility.

The 1988 DOE Record of Decision announced that all grouting and vitrification of the waste in the double-shell tanks would be completed in 2016 (DOE, 1988). Under that plan, DOE-EM would defer decisions on the single-shell tanks until about 2015. In November 1989, DOE awarded a $550 million construction contract to start building the High-Level Waste Vitrification Plant, and the TPA called for construction to begin in July 1991 (GAO, 1991). Pre-treatment was to be done in the World War II–era B Plant (DOE, 1988). Here, pre-treatment refers to separation of the tank waste into high-activity and LAW portions prior to the treatment stage that would produce the waste forms for each portion. B Plant would have used a process then being developed called Transuranic Extraction (GAO, 1991). By 1994, 14 grout vaults for the LAW portion were to be constructed (Dunning, 2016). Eventually, dozens of vaults would have to have been constructed.

In 1990, DOE determined that it could not defer a decision on treatment of the single-shell tanks because of various hazards associated with those tanks. Notably, the Defense Nuclear Facilities Safety Board (DNFSB) issued recommendations in 1990 to DOE to take corrective action on these tanks. DNFSB’s Recommendation 90-3 (issued in March 1990) called for DOE to develop a plan for responding to unexpected degradation of a tank or its contents and to an explosion in a tank (DNFSB, 1990a). Then in October 1990, because the DNFSB concluded that DOE’s proposed implementation plan was not adequately responsive, it issued Recommendation 90-7 that specified: “Immediate steps should be taken to add instrumentation to the single shell tanks containing ferrocyanide that will establish whether hot spots exist or may develop in the future in the stored waste.” In addition, that recommendation called for other sensors, instrumentation, and sampling to meet “the urgent need for a comprehensive and definitive assessment of the probability of a violent chemical reaction” (DNFSB, 1990b). The DNFSB’s nuclear safety oversight and action-forcing recommendations have continued to the present day.

In addition, in January 1991, Senator Ron Wyden of Oregon issued a watch list covering 56 single-shell tanks and detailing several hazards, including criticality, hydrogen gas, flammability, and organic chemicals. While these watch list problems were resolved by 2001, concerns have continued about the status of the tanks, leaks from some tanks, and the potential for additional leaks or structural failure (e.g., collapse of a tank roof). (All of these scenarios are included in the term “failure,” as used in this review report.) For example, Senator Wyden has underscored the urgency in dealing with the tanks, and in 2013, he called for an investigation by the GAO about the tank leaks and potential for further leaks (GAO, 2014). According to this GAO investigation, from 2012 to 2014, DOE assessed the physical condition of the tanks and “found them to be in worse condition than it assumed in 2011 when developing its schedule for emptying the tanks.” In addition, as of November 2014, when the GAO finished its investigation, “DOE’s current schedule for managing the tank waste does not consider the worsening conditions of the tanks or the delays in the construction of the Waste Treatment and Immobilization Plant” (GAO, 2014).

Because of the tank waste concerns of the early 1990s, DOE redesigned its cleanup plan to include treatment of all (single-shell and double-shell) tanks. This revised plan resulted in adjustment of the TPA milestones and changes in the earlier proposed pre-treatment and treatment approaches. In June 1991, for example, a GAO investigation pointed out that the B Plant for pre-treatment would not meet regulatory requirements. In particular, the GAO report stated that a 1989 DOE study found that

Subsequently, in December 1991, DOE decided against using the B Plant for this purpose. By late 1992, the plan to grout the LAW was also dropped because of technical problems, including pipes that clogged and leaked and the poor retention of technetium in the grout formulation being considered at that

time. Additionally, revised costs for the grout plant exceeded the projected costs for the vitrification plant for the LAW (Dunning, 2016).

In 1993, DOE’s strategy called for completing the treatment facility prior to fully developing all other aspects of the waste treatment program. But after DOE had spent about $418 million, it recognized that the planned treatment facility would not have the capacity to treat all of the waste within the time frame acceptable to EPA and the Department of Ecology (GAO, 2015). As a result, DOE proposed changes to the TPA. In 1994, after renegotiation, the TPA was amended to extend the target date for mission completion to 2028. Vitrification was to proceed as a two-stage process: first a pilot plant would treat 18 percent of the waste, and then a second facility would vitrify the rest. Concerns soon arose that, after construction of the first plant, there would not be enough money available to build the second (Dunning, 2016).

To try to implement a proposed cost-effective approach, in September 1995, Secretary of Energy Hazel O’Leary announced a privatization arrangement under which the contractor would finance, design, build, and operate the facilities, and would receive payment via a fixed price contract from DOE. DOE initially estimated that the first phase of the project would have a contract price of $3.2 billion to treat about 10 percent of the waste in the pilot-scale facility. From 1996 to 2000, the price increased to more than $14 billion. In June 2000, DOE cancelled the contract. About $300 million had been spent, mostly on plant design (GAO, 2015).

In December 2000, DOE awarded a cost-reimbursable contract with incentive fees to Bechtel National, Inc., the current contractor in charge of the WTP construction, to complete the facility that the previous contractor had started to design. The initial estimate was that this pilot-scale facility would cost $4.3 billion and would be completed in 2011. In October 2002, the contractor recommended and DOE then authorized design changes that would eliminate the pilot-scale facility and instead scale up the WTP capacity to accelerate the cleanup and save an estimated $20 billion. In April 2003, DOE completed the renegotiated contract to include these design changes for the WTP project (GAO, 2015). Since then, there have been several WTP project schedule slips: in 2003, the projection was to start hot operations in 2007; in 2005, the projection was to start in 2017; in 2007, it was to start in 2019; in 2012, it was pushed to 2022; and in 2016, it was moved to 2036 (Dunning, 2016).

Notably, even after the cancellation of the grout plant in 1992, DOE has considered ways to reduce costs and schedules by using methods other than vitrification. For example, on November 14, 2001, Assistant Secretary for Environmental Management Jessie Roberson sent a memorandum to the Director of the Office of Management, Budget, and Evaluation at DOE that outlined a plan that would not vitrify about 75 percent of the LAW, and would develop two alternative technologies that could include grout and FBSR waste forms (Roberson, 2001). In addition, DOE examined an alternative vitrification technology known as bulk vitrification, which uses electrodes to melt waste, soil, and glass forming chemicals in a one-time-use container shaped like a dumpster. Bulk vitrification at that time looked to be a cheaper and faster form of vitrification for the low-activity waste. But in 2008, the bulk vitrification project was terminated due to technical and cost concerns (Dunning, 2016).

Presently, to keep the treatment of the HLW in the WTP on track over time to meet the amended TPA milestones, the 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).

REVIEW REPORT ORGANIZATION

The remainder of this review report proceeds in two parts. In Chapter 2, the committee provides its technical review of the FFRDC’s final draft report, dated April 5, 2019, and the set of slides that the FFRDC presented at the public meeting on May 16, 2019. This technical review is based on the factors identified in the committee’s Statement of Task (see Appendix D). The committee’s findings are at the end of that

chapter and are intended to focus on potential improvements in any follow-on efforts. In Chapter 3, the committee poses questions that a decision-maker might ask when making a decision on the preferred alternative for the SLAW treatment and then addresses how the FFRDC’s final draft report does or does not provide an adequate technical basis for the decision-maker to choose among the alternatives considered. The chapter concludes with the committee’s recommendations.

2

The Committee’s Technical Review of the FFRDC’s Final Draft Analysis

For this review, the Statement of Task (see Appendix D) requires the committee to provide its overall assessment of the Federally Funded Research and Development Center’s (FFRDC’s) report in final draft form, as also required by Section 3134 (Sec. 3134) of the National Defense Authorization Act of Fiscal Year 2017 (see Appendix C). In this chapter, the committee gives its technical review of the FFRDC’s report dated April 5, 2019. That report’s chapters are listed in Table 2-1, and the report is available on the National Academies of Sciences, Engineering, and Medicine’s (the National Academies’) website.¹ The committee has also included in its review the set of slides presented by the FFRDC team at the May 16, 2019, public meeting in Kennewick, Washington. Those slides are available on the National Academies’ website.² The committee’s technical review follows the topical elements—specified in the major section headings—in study charges one through four in the Statement of Task.

TABLE 2-1 List of the Chapters and Appendixes in the FFRDC Final Draft Report, “Report of Analysis of Approaches to Supplemental Treatment of Low-Activity Waste at the Hanford Nuclear Reservation,” Dated April 5, 2019

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¹ See http://dels.nas.edu/resources/static-assets/nrsb/miscellaneous/ffrdc-2019-4.pdf.

² See http://dels.nas.edu/Past-Events/Meeting-Supplemental-Treatment/DELS-NRSB-17-02/10052.

GENERAL OBSERVATIONS

This section examines the FFRDC report as a whole and from the perspective of its intended audience. The committee notes favorably that the FFRDC has done a considerable amount of useful analytic work and that the FFRDC’s analysis has evolved and improved over the course of the team’s work. However, as may be evident from the list of chapters and appendixes (see Table 2-1), the report is lengthy (278 pages) and parts of it are highly technical.

It is understandable, and unavoidable, that the FFRDC report is lengthy and highly technical, because treatment of supplemental low-activity waste (SLAW) is a complicated and technically challenging matter. Several consequences, however, arise from the technical content and length of the FFRDC report. First, the lengthy technical content does not explicitly address the concerns that people in the Hanford region have faced in the past, face today, and will face in decades to come. In fairness to the FFRDC, its task was to review existing waste disposal technologies for supplemental treatment of low-activity waste (LAW). Moreover, to the credit of the report’s authors, they mention the urgency of the schedule for waste treatment and call this out in their Executive Summary. Even so, a reader easily could miss the pressing concerns about the waste tanks, the potential for future failures, and the hazards of the tank waste to current and future generations. Notably, extending tank cleanup schedules—whether it be the result of seeking better technologies, funding limitations, or technology or project management inadequacies—increases the chance that additional tanks will fail and release radionuclides and hazardous chemicals into the air or subsurface environment. Such an event is likely to cause even more delays and funding shortfalls as resources are diverted to address the consequences of the failure.

Second, as a consequence of the length and the technical nature of the report, the Executive Summary takes on increased importance as a means to guide the reader, especially a reader without extensive technical expertise in radioactive waste and disposal technologies. In all likelihood, the Executive Summary will be read by the largest number of people. Likewise, the report might also be improved by an introductory chapter or a “Reader’s Guide” (similar to what long technical documents such as Environmental Impact Statements have included), using to the extent possible laypersons’ terms.

In this chapter, the committee describes its primary findings concerning the FFRDC’s final draft analysis report. The narrative text of the chapter is organized to reflect the committee’s Statement of Task, but with formal findings collected at the end of the chapter because they often incorporate material from multiple parts of the Statement of Task and text. The analysis in this chapter’s text and findings are informed by the following questions:

• Does the FFRDC analysis rise to a level that it is useful to the decision-maker, and if so how?
• Does the FFRDC analysis describe a framework of decisions that need to be made?
• Does the FFRDC report provide a strong technical basis in support of the major decisions to be made?

This chapter is informed by the committee’s understanding of its fundamental task as a peer review of a report that describes alternative courses of action, and neither the FFRDC’s report nor the committee’s review is intended to select a preferred approach.

METHODS USED TO ASSESS RISKS, COSTS, BENEFITS, SCHEDULE, AND REGULATORY COMPLIANCE AND HOW THEY WERE IMPLEMENTED

Risk Analysis

Risk Assessment Methodology

The portion of the report on “Risks” (section 2.1, p. 23) includes the following statement on the FFRDC team’s methodology for risk analysis:

Appendix E of the report goes on to explain that it used expert elicitation with team members as the subject-matter experts in a process that “involved team brainstorming to systematically identify and characterize risks associated with each technology option.” The team’s intent was “to establish a basis for preliminary risk-informed comparison between options as currently defined.” Moreover, the team sought “to obtain approximate, comparative risk rankings of the technology options considered.”

Appendix E identifies the scenarios that were considered in the exercise and reports their qualitative likelihoods. However, it does not provide any narrative explaining what the overall evaluation results mean for readers who are not familiar with risk analysis methods. Instead, it quickly follows the listing of the scenarios with a list of reasons to consider the exercise incomplete. In Appendix E, the FFRDC team describes two principal reasons why the scope of the scenarios it considered were incomplete (as paraphrased and quoted from p. 148 of the FFRDC report):

• Intended scope limitations, or known unknowns, mean that the convened experts did not have the ability to assess certain classes of risk. For example, a class of risks includes those beyond the control of the project. These classes of risk were mentioned in a list of programmatic risks, for example, the risk that there is inadequate funding appropriated for the project, but not analyzed further.
• Unintended scope limitations, or unknown unknowns, refer to possible scenarios that could adversely affect the tank waste cleanup mission but that the FFRDC did not identify. Such limitations are inherent in any risk assessment. However, “the strength of risk assessment as a specific approach resides in its ability to provide a systematic and transparent basis for decision-making in light of the information and knowledge available.”

The committee notes that the list of known unknowns, or system risks (in Table E-3 on pp. 150-151 of the report) could cause the reader to question the usefulness of the analysis done under constraints, and that the reader’s questions could unnecessarily undermine the insights from this part of the FFRDC’s work. The committee also notes that, setting aside the unavoidable presence of intended and unintended scope limitations, the list of scenarios that would reasonably fall within the intended scope may not be as complete as it could have been. For example, while Appendix E does consider the scenario where the grout formulation does not meet the performance expectations and permitting requirements of the state regulator, it does not appear to consider the scenario that the regulator rejects the Performance Assessment (PA) performed by the U.S. Department of Energy (DOE) for the vitrified LAW per se and the grouted secondary waste for

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³ In this context, “risk” is used in its general sense: “A probability or threat of damage, injury, liability, loss, or any other negative occurrence that is caused by external or internal vulnerabilities, and that may be avoided through preemptive action” (www.businessdictionary.com). It is not used in the context of human health risk.

the Integrated Disposal Facility (IDF). This gap in the analysis is problematic, because such a rejection would affect the ability to dispose of vitrified LAW or SLAW, and the associated grouted secondary waste in the IDF. The committee does not discount the usefulness of the FFRDC’s risk evaluation, but believes that the report would benefit from better integrating the risk assessment insights into a discussion of uncertainties in the main report.

Discussion of Uncertainties

The FFRDC has not properly presented the uncertainties elicited in the team’s risk assessment. Uncertainties are large and fundamental to nearly every aspect of the risk analysis, yet the report is relatively terse in identifying the various sources of uncertainty and, especially, the probability distributions that characterize each source. Given the high degree of sensitivity to risk in Hanford decision-making, it is important to understand, even if only in qualitative terms, whether the uncertainty is clustered around a central value, or whether it ranges across a wide spectrum of values. Similarly, it is also important to understand whether the uncertainty is symmetrically distributed above and below a central value, or whether the range is wider to the high or low side of the central value.

In the FFRDC report, after listing the risk scenarios evaluated, and assigning them qualitative likelihoods and consequences, the only summary provided in Appendix E is in Figure E-4 (on p. 150). This figure is a bar chart of expected values for the cost and schedule risks of each of the five technology options.⁴ The committee notes that the purpose of a risk assessment is to characterize the full range of uncertain values and the relative likelihood of outcomes over that full spectrum. Expected values are summary metrics that mask all of that subsumed information on uncertainty and risk, and so they are only useful when making decisions on a risk-neutral basis (i.e., when making a decision that is insensitive to the scale or tendency of the risks as compared to other factors). Risk neutrality has certainly not been a defining attribute of decision-making regarding the disposition of wastes at Hanford. Table E-2 and the cost-risk equation below this table on p. 146 of the report indicate how the FFRDC used the elicitation results quantitatively to develop the expected values presented in Figure E-4. It would, in addition, have been useful in Figure E-4 to indicate the full range of potential cost and schedule outcomes around those expected values, for example, in the form of a diagram that indicates the minimum, lower quartile, median, upper quartile, and maximum values (a box-and-whisker plot).

The committee also notes that the information in Appendix E mentions the potential that each technology option may cost more than one would estimate from the standard engineering-based evaluation that is presented in the cost section of the report (which is the source of the cost ranges in Table 2 of the report), and it is likely that these cost risks would have to be layered onto the cost ranges presented in the summary tables, Tables 2 and 10 of the report. The same is true of the schedule uncertainties.⁵ However, the report provides no acknowledgment of the presence of greater uncertainty than is reported as apparent cost and schedule uncertainties in Tables 2 and 10. Thus, the FFRDC report does not represent the full range of uncertainties in costs and schedules that the FFRDC team has actually assessed.

Analysis of Costs and Benefits

Full Consideration of Benefits

In Section 2.2 of the report (p. 24), the FFRDC mentions the assessed benefits or advantages of each approach to treating Hanford SLAW, including waste form volume of both primary and secondary wastes,

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⁴ The chart in the FFRDC report uses the term “expectation values,” which is a term more common to physics than to risk analysis, and itself lends to the overall opacity of the discussion. The committee prefers to use the more common term “expected value.”

⁵ During a question-and-answer session at the May 16, 2019, public meeting, the FFRDC confirmed that the cost ranges in Table 2 do not reflect the cost uncertainties explored in Appendix E.

pre-treatment requirements, ease of operation, and flexibility, and notes that the “benefits of the individual treatment options are summarized in Section 3.0 and detailed in Appendices A-D.”

For the benefits of vitrification of the SLAW, Section 3.2.4 (p. 38 of the report) mentions (a) that design of the SLAW facility can be leveraged from the existing design for the primary LAW treatment facility in the WTP and thus is the “most technically mature technology;” (b) the waste form “has been studied extensively, so minimal further research is required;” (c) the high-temperature process destroys land disposal requirement (LDR) organics and most nitrates; and (d) the primary waste volume is comparatively low. The committee questions the claim that LAW vitrification is the most mature of the three treatment technologies. While it will undoubtedly be possible to capitalize on the research and design work underpinning the WTP LAW vitrification facility, this facility has itself neither been completed nor has it operated, and its scale is greater than any other experience with waste similar to Hanford LAW. In contrast, the Savannah River Site (SRS) has been grouting and disposing of similar LAW at an industrial scale for years with apparent success.

For the benefits of grouting of the SLAW, Section 3.3.4 on pp. 43-44 mentions that (a) it is the least complex process of the three options; (b) the process occurs at ambient temperatures and thus would not have the safety hazards to workers that high-temperature processes have; (c) it has the capability for relatively quick startup and shutdown that would more effectively accommodate variations in the SLAW feed rate; and (d) it has the lowest volume of secondary waste volume because the low operating temperature results in minimal off-gas. The committee notes that having start/stop capability may be particularly important because the SLAW is planned to receive the excess LAW that WTP cannot process and the receipt rate is projected to be highly variable (see Figure J-7 on p. 267 in the FFRDC report).

For the benefits of steam reforming of the SLAW, Section 3.4.4 on p. 50 mentions that (a) this process can tolerate variations in the SLAW feed rate and compositions and thus could give the flexibility to shut down temporarily or be operated with reduced feed rate; (b) it can efficiently destroy hazardous organics, nitrates and nitrous oxides, and ammonium compounds; (c) recent waste form durability tests indicate that this process can produce a durable waste form that would not increase waste volume during treatment and would not have liquid secondary wastes; and (d) because this process has a somewhat lower temperature as compared to vitrification, it reduces the amount of semi-volatiles that would be sent to off-gas and thus minimizes the recirculation in the treatment system of volatile and semi-volatile effluents. The committee notes that a high-temperature process such as steam reforming would entail an extensive off-gas processing system that would still produce some “secondary wastes” (e.g., see Figures D-2 and D-7 in the report). The report states that technetium and iodine will be completely removed by scrubbing and internally recycled (see Figure D-1); no separation process is complete. Also, the FFRDC analysis assumed that the carbon sorbents and high-efficiency particulate air (HEPA) filters do contain some technetium and iodine, even considering the effect of the recycle loop of the off-gas technology.

Section 4.1.2 on (pp. 57-58) provides the FFRDC’s high-level summary and comparison of the benefits of these options, which addresses an observation in the committee’s previous review (NASEM, 2018b) by “discuss[ing] or list[ing] the benefits for consideration of each treatment option,” which the previous FFRDC draft report did not do.

Consideration of Costs

The FFRDC report on p. 25 states that cost estimates for each SLAW technology “are full life-cycle costs, which include technology development, construction, operations, transport, and deactivation and decommissioning.” Sections 3.2.5, 3.3.5, and 3.4.5 provide summaries of the cost estimates for vitrification, grouting, and steam reforming. Appendix H provides a detailed discussion of cost estimation methodology. Section 4.1.3 on (pp. 58-59) has a brief discussion about cost comparison among the technology options. Cost and schedule estimation ranges are listed in Tables 2 and 10. The FFRDC’s final draft analysis concluded 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, and are based on costs from similar technologies, as well as assuming ideal funding conditions (i.e., no funding caps) and no redirection during a multi-year effort. Thus, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, but are unlikely to be much lower. However, as discussed in this review’s section on “Risk Analysis,” these cost ranges provide the reader with a potentially incomplete view of the full range and nature of cost uncertainty.

Cost-Benefit Reasoning

Sec. 3134 (see Appendix C) calls for an “analysis” of the “benefits and costs of such [treatment] approaches,” but not a cost-benefit analysis per se. As the committee has noted in prior reports (NASEM, 2018a,b), Sec. 3134 does not call for a comprehensive comparative analysis that would identify a preferred alternative. The distinction is important, as the preferred alternative analysis requires crucial judgments by decision-makers that are in no way factual, but rather involve values, legal and regulatory compliance, policies, and many other considerations. This is beyond the scope of Sec. 3134 and thus the task set out for the FFRDC and the committee. Moreover, a comprehensive preferred-alternative analysis would invade the province of the elected and administrative bodies (DOE, state regulators, and Congress) that are established to make such choices on behalf of the public.

The FFRDC team made some initial steps along the lines of performing a preferred-alternative analysis in an earlier report, but withdrew them from the current draft after the committee cautioned against it. Instead, the committee recommended (NASEM, 2018b) and the FFRDC team provided a qualitative comparison of relevant considerations. It is summarized in a large table (see Table 10, p. 61 of the FFRDC report), whose contents are drawn from the report and appendixes. What is currently missing, however, which would help to inform the ultimate selection of a preferred alternative by decision-makers using the FFRDC report is a summary of findings in a format that reflects the “marginal analysis” perspective that is fundamental to the logic of cost-benefit analysis. A cost-benefit optimum occurs when the marginal cost of “doing more” is equal to or greater than the marginal benefit gained by that increment in cost. Such an analysis is particularly appropriate when selecting among SLAW treatment alternatives that represent a discrete part of a larger system that is mostly well established (e.g., Hanford tank cleanup), and the differences in their costs are very large. This is a perfect setting for “cost-benefit thinking” of the type called for by Sec. 3134. For example, as one considers adopting a higher-cost option over a lower-cost option, one should ask how much the benefits of the higher-cost option are improved, and furthermore, to directly consider whether those incremental benefits are significant enough to be “worth” the incremental cost that would be absorbed. In addition, because the differences in benefits among the technology options at issue here are not along a single continuum, but have multiple attributes [as discussed in “Full Consideration of Benefits” above], an incremental approach to comparison of options could be extremely useful in bringing clear insight to a complex and uncertain situation.

Ultimately, a preferred-alternative analysis will be required by decision-makers, who are the ultimate audience of the FFRDC report. It will be for them to choose and explain the reasoning for a particular technology (or technologies), and an analysis of costs and benefits, as required by Sec. 3134, will be an essential component of that preferred alternative analysis. More could be done to summarize the information in the FFRDC report in a manner that would be consistent with that decision process, even if it is to

be initiated by and completed in the future under the oversight of the decision-makers using the FFRDC report as input.

Schedule

Schedule Considerations

In Section 2.4 (p. 25), the report states: “Schedules were developed in conjunction with cost estimates for each case. The schedules reflect team experience in process development and recent DOE capital projects.” In Section 3.0, the team provides its summaries of the schedule estimates for each technology option. For vitrification in Section 3.2.6 (p. 39), the estimated time is 10 to 15 years considering the time to complete additional research and development, design, construction, and cold and hot start up. For grouting in Section 3.3.6 (p. 44) the estimated time is 8 to 13 years considering the same factors. For steam reforming in Section 3.4.6 (p. 51), the estimated time is 10 to 15 years, and that section points out that the technology maturation plan and full-scale design are expected to benefit greatly from the experience at Idaho National Laboratory (INL) in developing the Integrated Waste Treatment Unit, “though that potential benefit is not assumed in the current cost and schedule estimates.” Likewise, comparison with previous Hanford high-level waste (HLW) vitrification plant time estimates and actual results (see “Brief Historical Context” section in Chapter 1 of this review) could be informative of the potential gap between expectations and reality.

Impact of System Integration Failures

While the FFRDC has provided a rationale for its schedule estimates based on recent DOE capital projects, it has not considered the effects on the schedule of a technology functioning well as an individual component and not as a part of the larger integrated system. For example, an efficient and cost-effective method for removing iodine from the LAW being fed to the SLAW may exist or be found, but it could introduce chemicals into the product stream that are incompatible with the selected immobilization process. Given the complexity, interdependencies, and relative novelty of Hanford processes, system integration would have to be considered a significant technology risk.

Funding Risks

On pp. 24-25, the report provides information about annual funding requirements to complete the Hanford tank waste treatment mission beginning with current funding levels. This information shows the substantial increase in projected funding requirements to complete the WTP, to build tank farm infrastructure required to retrieve the tank waste and move it to the WTP via pipeline, and to build the SLAW facility using vitrification technology. In a nutshell, the estimated funding requirements increase from the current approximately $1.3 billion per year to a maximum of about $4.7 billion per year. Figure 2-1, reprinted from the FFRDC’s report, shows the stacked estimated costs for the annual estimated budget. These costs are almost totally driven by the capital costs for the WTP, tank farm infrastructure, and the SLAW treatment plant. The FFRDC report states that meeting the funding requirements is one of the major challenges in successfully treating the SLAW, and the committee agrees. The committee also notes that these annual funding requirements do not include requirements to continue aspects of Hanford cleanup other than tank waste, such as facility decontamination and decommissioning, managing contaminated subsurface water plumes, and maintaining and operating common site infrastructure (e.g., water, roads, electricity, effluent treatment, waste evaporators), with costs that vary but are around $1 billion per year.

The FFRDC’s analysis assumes that funding would be made available to meet the schedule’s order and scale of operations indicated in the annual funding requirement graph. However, on p. 24, the report points out “project funding has often been ‘capped,’ i.e., annual funding limited, independent of the project estimate.” If this continues to be the case, SLAW technology development, facility design, and facility construction would compete for priority and funding with other large capital expenditures at Hanford including Direct Feed Low-Activity Waste treatment, WTP’s major construction projects, tank waste retrieval, and other operations involving the tanks. Thus, the duration of the Hanford tank cleanup mission would inevitably be substantially increased.

Regulatory Compliance

The FFRDC report (see Section 3.2.7, p. 39; Section 3.3.7, p. 45; Section 3.4.7, pp. 51-52; and corresponding sections in Appendixes B, C, and D) considers the three waste form options from the perspective

of their capabilities to meet applicable regulatory standards.⁶ For disposal in the IDF, the regulatory drivers for determining compliance are groundwater concentration limits for radionuclides developed by the U.S. Environmental Protection Agency (EPA) under the Safe Drinking Water Act, which are part of the DOE orders under which the IDF is regulated. Such requirements are not applicable at the Waste Control Specialists (WCS) site because this site is licensed under the U.S. Nuclear Regulatory Commission’s regulations (10 CFR part 61), which do not require compliance with the Safe Drinking Water Act. Both sites will be required to meet disposal standards (LDRs) under the Resource Conservation and Recovery Act (RCRA) concerning wastes containing hazardous chemicals. Meeting the RCRA requirements typically requires waste treatment to destroy or immobilize hazardous chemicals. The FFRDC team in its report did not directly discuss environmental and human health risks but in effect considered these in its analysis of regulatory compliance.

The use of the radionuclide drinking water concentration limits is a reasonable surrogate for human health risk as a first order of approximation. Moreover, for any of the alternatives to be feasible, it must be capable of complying with the applicable regulations such as drinking water standards. A thorough risk assessment and cost-benefit analysis would need to evaluate other exposure pathways (even if only to assure that the drinking water concentration is at least as protective), and to evaluate the benefits to be gained from additional protective actions or lost by other alternatives.

WASTE CONDITIONING AND SUPPLEMENTAL PRE-TREATMENT APPROACHES CONSIDERED IN THE ASSESSMENTS, INCLUDING ANY APPROACHES NOT IDENTIFIED BY CONGRESS

Sec. 3134 directed the FFRDC to perform an analysis of the risks, benefits, costs, schedules, and obstacles for removal of iodine-129 and technetium-99 from the SLAW for immobilization with the HLW. This highlights the fact that the identified approaches—vitrification, grouting, and steam reforming—are part of a larger system that provides the LAW feed and considers multiple potential disposal locations. In addition to the LAW feed from other parts of the tank waste remediation system, the SLAW facility will produce and have to manage its own secondary wastes and may include pre-treatment to make the SLAW more suitable for treatment or disposal. While these aspects precede and follow the central treatment approach, respectively, they can have a profound impact on the risk, cost, and benefit of the central approach.

Broader Waste Management System

The SLAW treatment technology is a relatively small part of a large, interrelated system that includes subsystems for treatment of the HLW and primary LAW, as well as tank operations. Following the congressional mandate, the FFRDC has focused its analysis within this relatively narrow scope of supplemental treatment of the LAW. The FFRDC team has analyzed three immobilization technologies identified in Sec. 3134: vitrification, grouting, and steam reforming.

Vitrification

This is a high-temperature technology that blends the SLAW with glass forming materials at about 1,150 °C, incorporating most of the radionuclides and metals into a glass waste form. The vitrification and off-gas systems destroy the LDR organics and some of the nitrates. Water is not incorporated into the glass, so it is treated in an effluent management facility to yield a large volume of grouted secondary waste. Solid secondary wastes (e.g., off-gas filters) that are generated are grouted (see separate discussion of secondary wastes below).

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⁶ See Appendix A of this review report for the list of relevant standards as specified in the congressional mandate and Appendixes F and I of the FFRDC report for more detailed information.

Grouting

Grouting technology operates at room temperature (≈25 °C) and blends the liquid SLAW with dry inorganic materials to produce a cementitious waste form. All radionuclides, metals, and organics are incorporated into the grout, producing a very small amount of secondary wastes from filters and used equipment. Pre-treatment (see separate discussion below) to remove or destroy LDR organics may be needed.

Steam Reforming

This high-temperature technology blends the liquid SLAW with dry inorganic materials at 750 °C, forming dry granular mineral particles with a chemical structure that retains the radionuclides and metals. The particles can be mixed with additives to produce a monolithic solid waste form. This process also generates secondary wastes that the FFRDC assumed would be grouted.

In previous reviews, the committee accepted the FFRDC’s choice to study only these three primary treatment options. As implied by the congressional directive to study these particular technologies, they are familiar and relatively well understood—which is not to say completely understood—technologies, and so the FFRDC’s choice has merit especially given the looming Tri-Party Agreement milestones. At the same time, it is inevitable that further use of these technologies over time, whether at Hanford or elsewhere, will result in better understanding and improvements in the process and output—all the more so because the Hanford cleanup project is to last for decades. Moreover, given the need for waste disposal in many settings (beyond DOE, beyond nuclear), it is entirely possible, even likely, that entirely or partially new technologies will emerge that would be useful for the SLAW. Therefore, because new technologies, improved existing technologies, or new combinations of existing, improved, and new technologies may represent the best way to address the SLAW as the project develops over the next decades, it would behoove DOE to make choices now that do not foreclose the testing and adoption of treatment approaches that are not apparent or whose large-scale adoption is not yet warranted.

In addition to the three primary treatment options, the FFRDC also identified two near-surface land disposal options to analyze and compare. The IDF located at Hanford is considered as the “baseline” LAW disposal facility. In this baseline option, the liquid LAW will be solidified using vitrification, and the secondary waste will be grouted. DOE plans to dispose of both types of waste at the IDF, but the Washington State Department of Ecology (the Department of Ecology) has yet to approve waste acceptance criteria that would allow disposal of grouted secondary waste or even the primary vitrified LAW. The second disposal site analyzed is operated by WCS, located near Andrews, Texas. WCS is sited in an arid and isolated region of western Texas and has become an active commercial low-level waste disposal facility in recent years. Also, the report briefly mentions (see Appendix F, p. 155) the possible use of the EnergySolutions facility near Clive, Utah, especially if pre-treatment to remove sufficient strontium-90 can produce Class A waste, which is required for acceptance at that facility.

The Major Role of Pre-Treatment

Sec. 3134 directed the FFRDC to perform an analysis of the risks, benefits, costs, schedules, and obstacles for removal of iodine-129 and technetium-99 from the SLAW for immobilization with the HLW. (See sidebars on iodine-129 and technetium-99 for contextual discussion about characteristics of these radionuclides.) Instead, the FFRDC performed an analysis of whether removal of these radionuclides is needed to comply with the relevant waste acceptance criteria and examined the status of technologies for removing these radionuclides from the SLAW feed stream. Section 3.1 and Appendix A of the FFRDC report has a fairly complete review of the pre-treatment techniques and options that are available for these waste streams.

Besides the possibility of pre-treatment to remove technetium (Tc) and iodine (I) as specified by Sec. 3134, there is discussion of the need to pre-treat for organic materials to meet the LDR for waste acceptance of grouted SLAW, as well as the pre-treatment of the SLAW to remove strontium-90 to reclassify as Class A low-level waste for off-site disposal to possibly reduce disposal cost at the WCS site.

During the information-gathering meeting on May 16, 2019, slide #37 presented by the FFRDC team concluded:

• Treatment for LDR organics may be required for some of the waste for both on-site and out-of-state disposal.
• Technetium and iodine removal is not needed for out-of-state disposal of grouted or steam reformed waste forms.
• Technetium and iodine removal is not needed for on-site disposal of grouted or steam reformed waste forms, assuming high-performing grouted and steam-reformed waste forms.

For radioactive waste disposal, the committee notes that the two mobile and long-lived radionuclides iodine-129 and technetium-99 are consistently important risk contributors. Two important questions for this analysis are (1) whether it makes sense to remove these two radionuclides from the SLAW and immobilize them with the HLW streams, and (2) whether technetium and iodine will meet EPA’s drinking water standard and, presumably, the yet to be determined waste acceptance criteria for the IDF.

Both the unpublished IDF PA and the FFRDC’s Performance Evaluation (PE) attempted to answer the second question. According to the PA results described by Pat Lee of Orano Federal Services at the information-gathering meeting on February 28, 2018 (Lee, 2018), and the summary of those results in the FFRDC report (see p. 166), the immobilized (vitrified) low-activity waste form “is projected in the PA to contain the majority of ⁹⁹Tc and ¹²⁹I.” Moreover, the report (p. 166) notes: “No performance objectives or measures were exceeded within the 1,000-year DOE compliance period.” However, according to the PA’s simulations, the release of iodine-129 would exceed the drinking water standard approximately 7,000 years after site closure. In comparison, the FFRDC’s PE concluded that on-site IDF disposal would not require the removal of these radionuclides. The differing conclusions in the PA and PE analyses concerning iodine-129 point to the importance of revealing the modeling assumptions. In particular, the committee believes there are large uncertainties associated with the unvalidated waste form degradation models and data used in the FFRDC’s PE analysis. Furthermore, what differentiates a “low-performing grout” from a “high-performing grout” from a “projected best” grout would have to be specified. Therefore, the conclusions from the FFRDC’s PE that removal of iodine-129 and technetium-99 for on-site IDF disposal are not necessary would benefit from further evaluation and validation. If it turns out that iodine-129 can be removed from the current LAW or otherwise mitigated by engineered disposal barriers such as getters (which are added materials that can retain contaminants of concern) or isotopic dilution, resulting in much more benign LAW streams, other disposal options may open up for the disposal of these radionuclides as well as the waste from the treatment process.

Similarly with respect to selenium-79 (see sidebar for contextual discussion), without the proper supporting documentation for the FFRDC PE, or the IDF PA on which the PE was based, the committee is unable to assess the potential significance of ⁷⁹Se and any other long-lived fission products. It would have been useful for the FFRDC to include the risk over time for ⁷⁹Se and all of the long-lived radionuclides that are indicated in Table F-2 of the report.

The Major Role of Secondary Waste

While the FFRDC report mentions the challenges of secondary waste in the Executive Summary and explains its origins in Appendix F, the committee believes that the FFRDC does not emphasize strongly enough to decision-makers the central role that secondary waste plays in meeting disposal waste acceptance criteria. Secondary waste is produced during the treatment (and pre-treatment if used) of the SLAW in differing amounts depending on the treatment method used and can include solid (such as HEPA filters) and liquid wastes produced during primary processing which are then assumed to be grouted. In particular, high-temperature processes volatize iodine and a small fraction of it is present in the grouted secondary waste forms.

Indeed, the grouted secondary waste has a disproportionate impact on the IDF performance and results in it being the dominant contributor to calculated dose during a 10,000-year period. Specifically, long-lived and mobile iodine-129 dominates the long-term health risks for all three treatment technologies. As shown in Lee’s presentation from the February 28, 2018, public meeting on the IDF PA, the time of peak dose for iodine-129 occurs in the 7,000 to 8,000 year period after emplacement in the IDF (Lee, 2018). Thus, the production of secondary waste streams for high-temperature processes (vitrification and steam reforming)—if left unmitigated—becomes an important decision factor among the alternatives.

Given the fact that the grouted secondary waste streams drive IDF performance (except for grout, where less iodine is in the secondary wastes and the dose from the primary waste dominates), it is surprising that the FFRDC did not spend more time analyzing mitigation actions both on the secondary waste form, but also in the IDF design (which, for example, takes no credit for using engineered fill materials as a radionuclide migration barrier). Accomplishing either of these mitigation actions could have a significant impact on performance of the IDF LAW disposal system (including waste form, fill material, liners, and caps) and potentially streamline the decision-making process. However, the FFRDC’s report does mention

the possibility of shipping grouted secondary waste to WCS while keeping vitrified primary waste at the IDF. Waste acceptance criteria at WCS are less restrictive than at the IDF because, in contrast to the IDF, WCS lacks an aquifer containing potable water under the disposal site.

OTHER KEY INFORMATION AND DATA USED IN THE ASSESSMENTS

Performance Assessment and Performance Evaluation of Waste Disposal

The compliance of primary (WTP) vitrified LAW disposal at the IDF relies on PA calculations (as specified in DOE Order 435.1; DOE, 2011b). The PA evaluated the performance of vitrified primary waste and grouted secondary wastes in the IDF, but did not address the performance of the IDF containing waste from the grouting and steam reforming alternatives. The report on p. 166 states the PA results for vitrified LAW as follows:

• No [DOE] performance objectives or measures were exceeded within the 1,000-year DOE compliance period. The highest calculated dose projected was for the chronic inadvertent intruder scenario where interception of four ILAW [immobilized low-activity waste] glass cylinders occurs from well drilling at the end of the institutional control period. In this case the dose is <50% of the 100 mrem/yr [milli-roentgen equivalent man/year] maximum dose rate performance objective.
• For the air and groundwater exposure pathways, the predicted dose during the DOE compliance period, is dominated by the air pathway for gaseous radionuclides, but is a factor of 50 below the 10 mrem/yr performance objective.
• Only the groundwater protection measure (beta-gamma dose equivalent) is exceeded during the post-compliance period (>1,000 years), where dose calculated using the EPA dosimetry method projects a dose rate of 4.9 mrem/yr (versus 0.4 mrem/yr beta-gamma standard) resulting from ⁹⁹Tc and ¹²⁹I within solid secondary waste, specifically the grouted granular activated carbon (GAC) and HEPA filters solid secondary waste (SSW).

To assess potential compliance of the SLAW and secondary waste disposal at the IDF from the grouting and steam reforming options, the FFRDC team conducted PE analyses that are similar to the PA methodology, and they validated the PE against the PA. The FFRDC team also conducted a PE of vitrified SLAW and secondary waste disposal using its own waste form models and assumptions. As discussed on p. 166 of the report, the results of the PE for all three waste disposal systems at the IDF extending to 500,000 years were that the calculated peak dose was less than 50 percent of the 100 mrem/yr dose rate performance objective. “After more than 200,000 years, radium-226 becomes a dominant dose contributor, but less so than the earlier peak doses from technetium-99 and iodine-129.”⁷ Thus, iodine-129 and technetium-99 were the only significant contributors to the peak dose, which occurred several thousand years after disposal site closure. The committee notes that preparation and release of PAs is beyond the scope of the FFRDC’s charge or resources. However, it is evident from the most recent report that the FFRDC has had access to draft PA analyses and results. The committee did not have access to the PA data and analyses, thereby, making it impossible for the committee to critically review the disposal performances of the three waste disposal systems. Moreover, 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.

Consideration of Experience at Relevant Sites

In a number of places the report mentions experience relevant to the SLAW, especially at DOE sites other than Hanford. Examples include the vitrification and grouting at the SRS, vitrification at the West

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⁷ Page 166 of the FFRDC report.

Valley Demonstration Project, and the steam reforming unit under development at INL. However, the mentions are just that. There is no analysis of what aspects of the experience are relevant to the SLAW or not, why this is the case, and the implications for the readiness of the various technologies for deployment. For example, extensive information exists on the design, cost, production, and performance of Saltstone at the SRS accumulated over nearly three decades. This information was used by the FFRDC to inform their cost estimates for the grout alternative. Because of the similarities in some of the wastes, the committee believes that there are lessons to be learned from the activities at other sites that are not reflected in the FFRDC report, not only regarding the design and operation of these similar facilities, but also regarding the performance of the grout waste form, which has been widely used to immobilize radioactive and chemically hazardous wastes. Discussion of this experience would help inform decision-makers. In addition, it would help to consider other useful, relevant experience at non-DOE sites to include commercial facilities, such as the operating steam reforming facility in Erwin, Tennessee. This would include analysis of pre-treatment and treatment alternatives for operations similar to those being consider for treatment of SLAW at Hanford.

While there undeniably are relevant differences among the sites’ respective waste streams, physical environments, regulatory requirements, and other factors, there are also similarities. Success or lack of success at another site does not directly translate to the same outcome at Hanford, but every experience offers lessons to be learned, and the FFRDC report would be strengthened by a candid assessment of such lessons. The committee recognizes that there is often cultural resistance to assessments, but DOE, like all other organizations, would benefit from learning from its own experiences across the DOE complex. Moreover, as suggested in Recommendation 3-1 (see Chapter 3), the long duration of the Hanford cleanup lends itself to a concerted effort to learn from experience at other DOE sites, at locations in other countries where these technologies are used, and from Hanford’s own experience over multiple decades.

In a similar vein, the report has a brief comparative discussion of differences among the current efforts and previous performance assessments (see Appendix F.4.3.3) and a very brief acknowledgment of previous comparative evaluations of technologies relevant to the SLAW treatment (Sec. 3.5). A few documents in both categories are referenced in the report. The committee believes that there is a need to systematically and transparently identify and compare the differences among the various historical documents at both levels to provide the basis for determining the credibility and shortcomings of the current analysis.

Other Needed Information

Meeting the Requirements of the Resource Conservation and Recovery Act of 1976

An important aspect of regulatory compliance is meeting the requirements of the RCRA. Some metals and organic chemicals that are known or suspected to be in the SLAW waste stream are regulated under the RCRA, which sets stringent land disposal restrictions for these materials based on their potential to leach into groundwater. Other chemicals suspected to be in the SLAW, such as nitrates, are regulated to prevent groundwater contamination. If these materials are destroyed or removed during the processing of the waste, or adequately immobilized in waste form, then near-surface disposal is not an LDR issue. However, if they remain, the LDRs represent a regulatory hurdle, and one which is in the control of state regulators under the terms of the Federal Facilities Compliance Act. Although the FFRDC report mentions the possibility that the LAW might require pre-treatment to meet LDR, its analysis of mitigation options is terse, and it is unclear whether or when mitigation will be needed and how the need will be assessed.

Enhanced Engineered Barriers for Iodine-129

Because of its characteristics (see sidebar), iodine-129 poses a particular challenge for disposal in either a near-surface facility or a geologic repository. Over the very long term, iodine-129 becomes an important contributor to dose calculations. For this reason, there has been a substantial amount of research, mostly funded by DOE, to investigate new materials for the selective removal of iodine from the HLW

waste streams, its incorporation into durable waste forms, and the development of getters to capture released iodine in the near-field of the disposal environment.

Although the report raises the possibility of using getters in the grout, the report does not provide an explanation or analysis of the materials that would be used, nor is the possibility of isotopic dilution discussed. Finally, the report does not consider a strategy for augmenting the design of the disposal site, for example, the IDF, to use getters in the fill material as a barrier to iodine release.

PRESENTATION OF ASSESSMENT RESULTS

Comparative Assessment of Waste Form Performance

In Review #2, the committee emphasized the need for a comparative assessment (NASEM, 2018b). One distinct element of the decision-making process will be to answer the question of whether the performance of the different waste forms has a significant impact on the performance of the disposal system. The answer to this question lies in an evaluation of the comparative material properties of the waste forms, their performance in the near-surface, disposal environment, and an understanding of how all of the elements of the disposal system actually functions individually and how they interact.

The FFRDC’s final draft analysis attempts to do this, but there are deficiencies to the FFRDC’s approach. Most noteworthy is the lack of a truly parallel analysis of the three waste forms. A parallel, comparative analysis would consist of three clearly presented and discussed steps:

• A clear definition of the waste feed stream (also called a feed vector) for each waste form. Although some data are given (e.g., Tables F-1 and F-2), these data represent examples at a specific time or global averages. In order to understand waste form performance, particularly of key radionuclides like iodine-129 and technetium-99, the analysis has to provide envelopes of composition that capture variations in the waste stream during processing. This may be important in determining whether the waste form can incorporate or encapsulate the waste stream’s radionuclides. More importantly, the type of processing, such as high-temperature vitrification versus low-temperature grouting, can change the immobilized waste stream composition. In the case of vitrification, small fractions of volatile elements, such as I (a few to 25 percent) and Tc (a fraction of a percent), are projected to be in the secondary waste streams, which are assumed to be grouted. Thus, the final disposal evaluation needs to consider not only the performance of the three waste forms, but also the performance of radionuclides in the secondary waste streams. Options for the treatment of the secondary waste streams also need to be described and evaluated.
• A comparison of material properties of the three waste forms. This should consist of four types of information:
  • A description of the basic waste form properties (e.g., waste loading and density), particularly properties that will affect performance, such as the composition of the glass, whether additional engineered barriers will be used in the grout, the permeability of the grout, and the microtexture of the glass ceramic that will result from steam reforming.
  • A description of the distribution and chemical speciation of key radionuclides within each waste form, particularly their redox state and the identification of other components that may change or control the redox state within the waste form.
  • A description of the radionuclide release mechanisms for each waste form, and a discussion of alternative mechanisms and why they were not adopted. The understanding of the mechanisms of release and retardation is a critical aspect of the models that were used in the PA.
• The last step in the comparison is the performance assessments of the waste forms in the disposal environment. If the PA and the PE calculations for the IDF had been available for the committee’s review, four issues would have been of critical interest:

The committee notes the following key points:

• A modeled demonstration of compliance is only the first step in a performance assessment or a performance evaluation. One also needs to develop a strong understanding of how the disposal system functions as a whole and be able to make a compelling argument for the selection of one waste form over another (what is sometimes known as the safety case). Even if all three waste forms comply with the regulations, that still does not mean that the differences in waste form performance have been captured by the analysis. Other parameters, such as the time to reach the peak radiation dose rate and the time for dose rates to diminish, may be relevant to the decision-maker’s consideration of the three technologies and their waste forms. The committee acknowledges that the FFRDC has made a valiant effort to compile and compare data on the different waste forms. Still, the lack of a fully transparent comparison between the three waste forms hinders the analysis.
• As noted above, the FFRDC report has very limited discussion of the Saltstone that is in use at the SRS (see pp. 93-94 in Appendix C). More details on the similarities and differences between the grout to be used at Hanford and the Saltstone at SRS would have added greatly to understanding how the grout is being modeled at the IDF at Hanford.

In summary, the FFRDC report fails to muster the extensive data in the literature on the different waste forms and present a comparison that highlights the pros and cons of each. The committee notes that this is attempted, as an example for grout (p. 92 in Appendix C), but this bulleted list is really just composed of assertions without reference to data or citations to relevant literature.

The “As Good as Glass” Conundrum

Much has been made, particularly by the Department of Ecology, of a supposed commitment by DOE that any treatment technology for the SLAW be “as good as glass.” While not found in so many words in federal or state law or regulation, the “as good as glass” concept has taken on a life of its own at Hanford. Some stakeholder groups advocate for it; the Department of Ecology and others have developed a set of legal arguments for “as good as glass”; and the Department of Ecology has offered some tentative criteria (see the presentation of Alex Smith, Washington State Department of Ecology, at the July 23, 2018, public meeting) by which another technology might be determined to be as good as (or not as good as) glass. In theory, the “as good as” formulation would allow DOE to pursue a treatment technology other than glass (vitrification). In practical terms, however, “as good as glass” forces DOE to adopt vitrification because the content and contours of the concept are undefined. The conundrum is that “as good as glass” can mean different things—often without a clear awareness of the differences by users of the term. The committee has heard discussions during its information-gathering meetings that imply at least three different meanings, as follows:

• First, in its narrow technical sense, it refers to the waste isolation capacity of the SLAW immobilization medium (e.g., glass or grout). This is fundamentally a question of materials science and chemistry. It is informed by laboratory experiment and mechanisms of isolation, and it can be evaluated based on a considerable technical literature with varying degrees of uncertainty.
• Second, in a technical but broader sense, “as good as glass” refers to the disposal system—not just the waste form itself, but the waste isolation effectiveness of the waste form, packaging, fill material surrounding the packages in the disposal trenches, the engineered barriers such as liners and caps that surround the trenches, and the natural environment surrounding this engineered system. Thus, the engineering of the waste disposal facility is relevant, as is the geology, geochemistry, climate, and hydrology of the environment in which the disposal facility is located.
• Third, “as good as glass” can refer to the overarching decision that DOE has to make among treatment technologies and disposal locations. That is, it can refer to the comparison of the baseline alternative involving vitrified SLAW, grouted secondary waste, and disposal in the IDF to grouting and steam reforming alternatives with disposal in the IDF and/or WCS on a multi-attribute basis. This, however, requires consideration of not only the physical characteristics of the waste, its form, and its placement, but all of the factors that will be considered by the decision-makers when selecting a preferred alternative. This means that, in addition to physical characteristics of the waste form and disposal site identified in the previous two bullets, one has to consider a range of quasi-technical factors including cost, reliability of technology, technological readiness, schedule, and safety, and their relative importance, i.e., “all things considered.” Additionally, it is important to note that there are secondary wastes from the vitrification and steam reforming processes that were projected to contain significant amounts of ⁹⁹Tc and ¹²⁹I, so this waste stream is the most important contributor to calculated dose rate as compared to the immobilized SLAW per se. In other words, “as good as glass” could mean the primary and secondary waste forms.

As can be understood from the above steps in the analysis of waste form performance, the judgment of whether other waste forms are “as good as glass” may be made at different levels: (1) the evaluation and comparison of the release rates from each of the waste forms based on laboratory data; (2) the waste form performance in the disposal system modeled over time; and (3) multi-attribute comparison of alternative disposal systems that include consideration of quasi-technical factors. At each step, the factors to be considered are different and increase in number.

The committee believes that waste form performance would have to be based on the comparison of waste form performance in the disposal sites over relevant periods, e.g., out to the time of the peak dose rate. All other points of comparison, e.g., materials properties, are components of the larger PA analysis. It is essential that the analyses supporting the selection of a preferred treatment alternative clearly distinguish among, and provide the necessary information for, analyzing all of these meanings of “as good as glass.” The technical assessment of the waste form per se and the technical assessment of the waste form in situ are essential elements of the larger decision but are far from the only elements that need to be considered.

The committee also notes that there may be opportunities to engage productively with the Department of Ecology to reach an agreement on the “as good as glass” issue. While this issue falls outside the scope of the FFRDC’s mandate, it is germane to the committee’s scope because Sec. 3134 requires the National Academies to “provide an opportunity for public comment, with sufficient notice, to inform and improve the quality of the review.” The Department of Ecology is a major stakeholder and a decision-maker because of its role as the state regulator with the authority to issue permits for the Hanford Site’s facilities such as the IDF, the WTP, and the SLAW treatment—or not. Department of Ecology representatives have provided substantive comments at every public meeting that the committee has held in the Hanford area. At the most recent public meeting on May 16, 2019, Suzanne Dahl, section manager of tank waste for the Department of Ecology, described the FFRDC’s final draft report as a “feasibility study” and as a “potential first stepping stone to changing SLAW treatment.” She also noted several new pieces of information in the report, including the “cost of nearly complete LAW vitrification plant,” (sic) “WCS as new candidate waste disposal site,” “new high performance grout waste form performance data,” and “new FBSR [fluidized bed

steam reforming] crystalline ceramic waste form performance data.” As to the high performance grout, she noted that the report indicates that this type of grout performs “better than the vitrification waste form performance.” She mentioned that these “results are contrary to 30 years of previous results” and that “Ecology has no comment on these results. Ecology has not completed evaluation of underlying studies and would need to complete a significant effort before concurring with the latest results.” The committee observes that Ms. Dahl’s remarks suggest an opportunity for DOE and the Department of Ecology to work together to take the next steps that she has outlined.

THE COMMITTEE’S FINDINGS

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

Finding 3-2

The committee did not have access to the 2017 IDF Performance Assessment (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 performances 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 3-3

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 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 time period 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 tank waste was 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.

3

The Committee’s Assessment of the Usefulness for Decision-Makers of the FFRDC’s Final Draft Analysis

The Federally Funded Research and Development Center (FFRDC) team was assigned a very large task in a short period of time, that is, to review a long history and large technical literature on three or more very different treatment technologies and, as the analysis developed, the permanent disposition of waste material in two (or potentially three) different disposal sites. As the committee has noted in previous reports and above, the choice among treatment approaches cannot meaningfully be made without consideration of the disposal environment and the quasi-technical factors identified earlier. The FFRDC team has, as the committee has also noted, worked very hard to grapple with the task it was assigned. It has gathered a large amount of information, performed various analyses on it, and adjusted its approach and presentation in response to comments. Nevertheless, as Chapter 2 demonstrates, there are significant technical limitations to the conclusions that can be drawn from the team’s work, especially regarding the analyses of costs and risks, as well as the uncertainties surrounding the technologies themselves, costs, and several important programmatic risks.

The committee’s review is constrained, it goes without saying, by the Statement of Task, which expressly calls for the committee to “evaluate the technical quality and completeness” of the FFRDC report on the treatment options for supplemental low-activity waste (SLAW). This is a double limitation: the committee’s report is to be “technical,” and the committee’s scope (following the FFRDC’s) includes treatment approaches to the SLAW plus the directly related ancillary processes such as pre-treatment and secondary waste management. Neither the FFRDC nor the committee was tasked to offer views on broader policy issues or on the overall system for managing tank waste at Hanford. While one may quite reasonably find such limitations frustrating and sometimes even question-begging, they represent Congress’s commendable effort to obtain a well-informed and reliable technical answer to a particular and important question before it.

Within the committee’s task of technical review, it may also be helpful to identify the ways in which the extensive information and analysis in the FFRDC report may best be used by Congress, the U.S. Department of Energy (DOE), and stakeholders, together with additional considerations that users should bring to the analysis. The committee’s overarching assessment is that the FFRDC report is a valuable feasibility or scoping (in a non-technical sense) report, which identifies the key alternatives as of now, and paves the way for more detailed evaluations. It also paves the way for adopting a more iterative approach to technology at Hanford, taking advantage of the distant time horizons to build in flexibility and learning. Such an approach could help to avoid the tank waste management project finding itself, in 2030, at the outer limits of available funding and schedule and yet bound by vintage technologies of 2020 with decades of waste management and disposal to go. Put another way, the high degree of difficulty and uncertainty in the FFRDC’s analysis at this point in time ought to counsel caution and humility in making expensive or even irrevocable choices for the long-term future.

This chapter focuses on the usefulness of the FFRDC’s final draft report to decision-makers. In effect, this congressionally mandated study resulted in an FFRDC report that provides an assessment of three major alternatives for supplemental treatment of low-activity waste (LAW) derived from material in the Hanford tanks as described in the FFRDC’s mandate. As mentioned earlier, the FFRDC team did not identify a preferred option by design, because it was not in their mandated scope, and the committee agrees with the team’s decision. The committee envisions that decision-makers will ask themselves a series of questions

during the decision-making process. This chapter provides the committee’s views on questions that decision-makers are likely to ask and the committee’s assessment of information available from the FFRDC’s April 5, 2019, report, and the FFRDC presentation slides from the public meeting on May 16, 2019, that could address these questions and what additional information is needed.

The committee assumes the decision-makers are senior policy-makers in the federal government (Congress and DOE’s executive management) and the state regulator (the Washington State Department of Ecology [the Department of Ecology]). They are also the primary audience of the FFRDC report, and that their decisions will be at the policy level. That is, they will be examining the relative priorities of the factors (decision criteria or “lines of inquiry”) analyzed in the report in the context of broader government priorities and available resources leading to identification of a preferred alternative or guidance on additional analyses needed to allow such an alternative to be pursued. Thus, what follows is essentially a guide to the report from the standpoint of decision-makers.

CONSIDERATIONS FOR DECISION-MAKERS

At the end of this chapter, the committee offers four recommendations: first, a general recommendation on the best way to understand and thus make productive use of the FFRDC report; second, specific issues around which a full decisional document should be organized; third, organizational structure to improve its usefulness to decision-makers; and fourth, using the FFRDC report as the basis for considering a more flexible approach to the SLAW (and possibly other aspects of tank waste management) that makes productive use of the long time horizon for cleanup.

While Congress did not specify that either the FFRDC team or the committee undertake formal risk assessments or cost-benefit analyses, such formal analyses, conducted with rigor, would greatly help to elucidate the relevant issues, choices, and uncertainties for well-defined paths forward. There are, and DOE and others have calculated them in the past, baseline risks and costs of the current situation with the Hanford tanks. That is, the risks, costs, and uncertainties of maintaining the waste at a level that minimizes the likelihood of release of tank waste to the extent feasible in their current configuration.

These baseline results provide a point of comparison with other pathways for waste management, specifically moving and treating the waste so as to achieve greater reduction of risk than is allowed by leaving the wastes in their present configuration. Additionally, DOE and others have performed analyses to support conclusions concerning the amount of waste that can be left in the tanks; this is the justification for constructing the multi-billion-dollar facilities to retrieve, store, and treat the tank waste. DOE has made the further decision to construct the multi-billion-dollar facilities on the basis of separating high-activity waste and LAW streams, and the particular flowchart on which these facilities are based requires the separate treatment of the SLAW.

The decision to adopt an approach that not only divides tank waste into high-activity wastes and LAWs, but also requires separate treatment of the SLAW, is the starting point of the FFRDC team and thus of the committee. As complex as the SLAW treatment question is, it is far less complex than the overall question of what to do about tank waste as a whole in its current configuration. Accordingly, it should be possible for a manageable number of pathways for treating and disposing of the SLAW to be identified and rigorously analyzed. The techniques of risk assessment, cost-benefit analysis, and uncertainty analysis are well suited for this task.

As stated in Chapter 2 of this review, the FFRDC team addresses the elements of such analyses for a reasonable selection of alternative pathways, but there are important gaps and omissions. Moreover, because the team was not directed to, and did not, perform rigorous analyses of risk, cost, benefit, and uncertainty, a decision-maker is not in a position to make a decision among pathways (technology approach and disposal site) solely on the basis of the FFRDC report. The following considerations therefore highlight the specific areas that a decisional analysis would need to address in detail and with rigor and, where possible, with quantification.

Are the Alternatives Adequately Defined and Described?

The FFRDC in its report considers three waste treatment immobilization processes (vitrification, grouting, and steam reforming) for the primary SLAW stream, and further possible pre-treatment processing to remove technetium-99 and iodine-129 to meet the requirements stated in the congressional mandate (see Appendix C). Additionally, during the course of the FFRDC’s work, the FFRDC identified the possibility of SLAW disposal at the Waste Control Specialists (WCS) near-surface disposal site near Andrews, Texas, and this is considered in the FFRDC report. The committee believes that this was a desirable addition to the scope of the analysis.

The committee has a number of concerns about the definition and description of the alternatives, as follows:

• There are many possible combinations of pre-treatment, treatment (immobilization), and disposal options. This fact, combined with waste acceptance criteria that differ at the two disposal sites considered (the Integrated Disposal Facility [IDF] and WCS) and, in the case of the IDF, are not yet approved, results in a confusing array of alternatives. In particular, the committee believes it will not be clear to the reader when and what type of pre-treatment is required or desirable for the various waste form-disposal destination combinations.
• The two high-temperature technologies (vitrification and steam reforming) produce secondary wastes (e.g., high-efficiency filters, liquids not suitable for release, and charcoal adsorbent beds) separate from the primary SLAW stream. In comparison, as a low-temperature process, grouting produces relatively minimal amounts of secondary waste; see p. 103 of the FFRDC report. The secondary wastes are assumed to be grouted and disposed of in the IDF in these alternatives, although the FFRDC does briefly discuss the possibility of sending this grouted secondary waste to WCS. In its report, the FFRDC mentions that vitrification produces the largest volume and the highest radioactivity content of secondary waste of the high-temperature primary treatment technologies, and that this secondary waste is the dominant source of radiation doses to a public receptor according to calculations examining a 10,000-year period at the IDF.
• The congressional mandate to the FFRDC calls for the analysis to include consideration of “Further processing of the low‐activity waste to remove long‐lived radioactive constituents, particularly technetium‐99 and iodine‐129, for immobilization with high level waste.” As noted in Chapter 2 of this review, further processing (pre-treatment) to remove these radionuclides is considered only from the perspective of SLAW regulatory compliance or changing the SLAW classification from the U.S. Nuclear Regulatory Commission’s Class B or C to Class A to reduce disposal costs at the WCS facility or possibly make the SLAW acceptable for disposal at the EnergySolutions facility near Clive, Utah. The possibility of moving these two radionuclides into the high-level waste (HLW) stream was not evaluated by the FFRDC in the report. In addition, doses from other long-lived, mobile radionuclides were not provided—selenium-79, in particular.

Taking these concerns together, decision-makers will need to carefully read the main report and possibly selected appendixes to understand the comparative advantages and disadvantages of the alternatives. This is especially the case when one considers the many externalities that are outside the FFRDC’s scope (see FFRDC report p. 11, “Significant Funding Needs,” and p. 13, “Emergent Studies and Future Scenarios”), but which could profoundly affect decisions on the SLAW treatment.

What Is the Level of Confidence That Each Treatment Alternative Will Meet Performance Requirements?

The FFRDC, in its final draft analysis, discusses the level of confidence that each alternative will meet its performance requirements in terms of its “technical maturity,” which is typically measured on a scale of technology readiness levels beginning with basic research and ending with commercial deployment of the

technology (DOE, 2011a). The FFRDC’s discussion is presented briefly, in qualitative terms, and without reference to an established scale. Some key aspects of the FFRDC’s discussion are discussed below.

The FFRDC report has neither a side-by-side comparison of the technical maturity of the major alternatives, nor a comparative discussion of the technical maturity assessment process used. If work on the analysis continues, it would be useful to include such discussion. The summary comparison tables (Table 2, p. 14, and Table 10, p. 61) state that vitrification is the most mature, FBSR the least mature, and, by inference, grout is intermediate. The committee offers the following observations on the FFRDC’s views:

• Technical maturity is an imprecise measure of the level of confidence as to how well a technology will perform. Whether a technology will perform depends on the competence of the designers, constructors, and operators, as well as the inherent characteristics of the technology. At this point, the committee believes technical maturity is not an appropriate measure, because there is no design, construction, or operation.
• The committee questions the FFRDC’s assessment that vitrification is the most technically mature technology for Hanford LAW. The FFRDC cites the Waste Treatment and Immobilization Plant (WTP) LAW vitrification facility as evidence. However, this facility has neither been completed, nor has it been operated. Radioactive waste has been vitrified at “industrial scale” at the Savannah River Site (SRS), with a somewhat different and more homogenous feed composition than at Hanford; it has also been vitrified at a few reprocessing plants around the world with a significantly different feed composition. The committee believes that the best evidence of the technical maturity for LAW immobilization is at SRS, where large volumes of low-activity alkaline salt-laden waste have been immobilized using grouting in near-surface vaults for years. Thus, the committee points to this evidence that grouting similar LAW appears more mature than vitrification but agrees with the FFRDC that fluidized bed steam reforming (FBSR) is the least mature immobilization technology.
• The FFRDC’s “bottom line” assessment of technical maturity is focused on the immobilization technology per se. However, the maturity of other aspects of each alternative needs to be taken into account. In particular, each alternative treatment technology requires pre-treatment of the feed stream and management of secondary wastes to varying degrees. The maturing of the necessary pre-treatment technologies does not seem to have been taken into account in the FFRDC’s assessment. The maturity of candidate pre-treatment technologies is summarized in Section (Sec.) 3.1 and detailed in Appendix A of the FFRDC report. In general, the committee believes that the pretreatment methodologies are less mature than vitrification and grouting, and perhaps even FBSR. However, while many component technologies to implement these pre-treatment options have been the subject of some research and development, the committee notes that the most challenging part of completing the WTP at Hanford has been the LAW pre-treatment facility.
• In addition to technical maturity (the current development state of the process), an important consideration when assessing whether a technology that has not been implemented can succeed is the technology’s complexity. Complexity is basically measured by how many things must simultaneously function properly for the technology to operate. The FFRDC does address complexity in its summary tables: vitrification is the most complex, grout the least complex, and FBSR intermediate. The committee accepts that grout is least complex. However, as with technical maturity, there is no side-by-side discussion of how complexity was assessed. Additional information on the complexity assessment would be useful.
• Finally, technical maturity is informed by experience elsewhere with similar materials. For the Hanford tank waste, the obvious analogy is the reprocessing waste at SRS. Indeed, the progress at SRS is a driver of Congress’s interest in an assessment of alternative approaches for Hanford SLAW. SRS has used both vitrification and grouting, and Idaho National Laboratory (INL) has used steam reforming. Careful analysis of each of these experiences is essential to a thorough review of technical maturity—with the important caveat that success or failure elsewhere is unlikely

• to be absolutely determinative of results at Hanford. For example, the composition of the vitrification feed stock at SRS was relatively uniform as compared to Hanford, and it is quite possible that each new batch at Hanford will have a different composition that will require individual adjustment. Moreover, the sheer complexity of the vitrification system operations mandates a lower technical maturity level than is currently projected. Likewise, the difficulties that steam reforming have encountered with INL’s calcined waste may suggest a fundamental difficulty with the technology, or after careful analysis, may be less relevant to Hanford’s waste or may be, in effect, the pilot phase of the technology that enables problems to be identified and resolved. In sum, technical maturity will be usefully informed by other, similar experiences, but will require careful analysis to assess.

How Will Each Waste Form Perform in Isolating Constituents of Concern?

The performance of each waste form as such depends on the materials science of the incorporation, corrosion, and release mechanisms. There are sizable technical literatures on each waste form based on theoretical work, laboratory testing, and experience in the field. It is not clear how the FFRDC used the available literature in its analysis or how they modeled the waste form performance. The committee also reminds the reader of the earlier discussion in this review that the waste form is just one component of the waste disposal system that includes other barriers to radionuclide transport.

How Will Each Waste Form Perform Over Time in the Expected Disposal Environments?

The FFRDC team identified two disposal options, and suggested the possibility of a third option at the facility near Clive, Utah. These represent a range of geologic, hydrologic, and other qualities that will have an effect on the transport and fate of any radionuclides that the waste form fails to isolate permanently. For each waste form, the decision-maker needs to understand how each disposal system will function over time in providing a barrier to the release of key radionuclides to the accessible environment, including technetium-99 and iodine-129. The FFRDC essentially concludes that all of the waste forms and their associated waste disposal systems can meet regulatory requirements with varying degrees of pre-treatment that have not yet been determined.

What Are the Estimated Costs? How Reliable Are They? and How Do They Compare to Other Known Costs at Hanford?

The FFRDC report has estimated costs for the alternatives (three treatment technologies, two disposal sites, five cases in all). The “bottom-line” results are in the summary tables of the FFRDC report (see Table 2, p. 14, and Table 10, p. 61) and in this review (see earlier section on “Consideration of Costs”); some discussion is in the main body of the report (Sec. 2.3); and more details are provided in Appendix H. However, the committee observes that additional cost uncertainty was characterized in the “semi-quantitative risk assessment,” described in Appendix E, but finds that these uncertainties have not been incorporated into these cost ranges. The reported cost ranges, as wide as they are, therefore appear to be more certain than the FFRDC team has actually determined. In Chapter 2 of this review, the committee has some detailed comments on the cost analysis. To make the most (or best use) of the FFRDC report, the committee offers the following points:

• The cost estimates are based on technologies that, for the most part, have not yet been fully developed or deployed at Hanford, and are based on costs from similar technologies, and assuming ideal funding conditions (i.e., no funding caps) and no redirection during a multi-year effort. Thus, there are large attendant uncertainties, suggesting that costs could be much higher than estimated, but are unlikely to be much lower.

• The FFRDC cost estimates (see pp. 11-12 of the report and Figure 2-1 of this review) indicate that Hanford tank waste cleanup (Office of River Protection budget) funding would have to increase two to three times the current budget level of approximately $1.3 billion per year to support any of the alternatives analyzed. In addition to this, the budget for non-tank-related cleanup (Richland Office budget) at Hanford typically adds almost $1 billion per year to expenditures at Hanford.
• Operational idiosyncrasies in the treatment processes are an important consideration in estimating costs. The assumed feed stream rate and composition to the SLAW treatment facility is currently projected to be highly variable and thus requires the facility to operate at varying levels or even be in standby mode for significant periods. The vitrification process must be “always on” to keep the glass in the melter from solidifying, whereas grouting and FBSR can be readily shut down and restarted as the situation demands.

Do the Alternatives Meet Safety Requirements?

Whether an alternative meets safety requirements is a false dichotomy. Engineered systems can virtually always be made to meet safety requirements, as they are expected to be, albeit at a cost that may include very high expenses, system complexity, and occupational risks. Thus, while the report concludes that “A viable SLAW treatment and disposal option can be developed for each of the three technologies evaluated” (p. 15, first bullet), and “all three primary waste forms can meet applicable DOE requirements for disposal at IDF or WCS” (Sec. 4.1.5)—this is not an especially useful conclusion. The real issue, as noted in the section in Chapter 2 of this review on cost-benefit analysis, is the cost and risk of the additions and their alternatives.

Therefore, some caveats have to be attached to the claims that fall into the category of the “additional cost” mentioned in the previous paragraph, as follows:

• All three alternatives involving disposal at the IDF may require mitigation measures for iodine-129 in the secondary wastes to meet U.S. Environmental Protection Agency (EPA) groundwater requirements. This is not an issue for disposal at WCS because this site is not classified as having a drinking water aquifer.
• Mitigation measures to meet EPA land disposal restrictions (LDRs) for organic chemicals may be required for a grouted waste form. This is not an issue for high-temperature processes such as vitrification and steam reforming because the organic chemicals are destroyed.
• The grouting and steam reforming alternatives that involved disposing of the primary SLAW waste at the IDF would need to overcome the stated preference of the Department of Ecology for a glass waste form (see the subsection in Chapter 2 on the “As Good as Glass” Conundrum).

What Are the Schedules for Implementation and the Uncertainties?

The FFRDC report has estimated schedule ranges for the time period to construct and to ready for operations for the three treatment technologies. As summarized in the report’s Tables 2 and 10, the estimated schedule ranges are 10-15 years for vitrification, 8-13 years for grouting, and 10-15 years for steam reforming. The report notes that: “The window to startup of any Hanford SLAW immobilization facility is 15 years (to 2034).” That is, according to the amended milestones of the Tri-Party Agreement, the WTP’s HLW treatment should begin by 2034 and the SLAW treatment should start concurrently. As this review states in Chapter 2, the subsection on “Schedule,” the FFRDC based these estimates on similar DOE capital projects. The ranges of the estimated schedules suggest that there are significant uncertainties in these estimates. Notably, the committee observes that additional schedule uncertainty was characterized in the “semi-quantitative risk assessment” described in Appendix E, but finds that these uncertainties have not been incorporated into the cost ranges that have some dependency on the duration of cleanup. The schedule ranges, as wide as they are, therefore appear to be more certain than the FFRDC team has actually determined.

The SLAW facility would be an integral part of the overall tank cleanup effort and, as a consequence, the nominal schedule for the SLAW is determined by its relationship to a number of other facilities and activities. The FFRDC adopted System Plan 8 (DOE-ORP, 2017) as its baseline for the schedule of major tank cleanup facilities and activities (see bullet points in the report on p. 12). For this baseline—which assumes that primary SLAW waste is vitrified—the planned start date of the SLAW operations would be 2034.

However, for the purposes of the FFRDC report—providing information to support a decision on the SLAW treatment alternative to be pursued—the more relevant information is the comparative time that would be required to bring each alternative from its current state of development to deployment in a facility ready to operate. The FFRDC developed information concerning the time required to bring each alternative to the point that it was ready for operation as part of its risk assessment using expert elicitation (see the report on p. 278 and Appendix E), which are summarized at the beginning of this section.

There are many attendant uncertainties in the schedule estimates, as follows:

• The estimates assume the tank cleanup program is fully funded as shown in Figure 2-1 of the report. Schedules will increase to the extent that the program is less than fully funded (see programmatic risks below).
• As noted above, the SLAW facility would be part of an integrated system of facilities and activities. To the extent that other facilities are delayed for whatever reason, this could affect the schedule for the SLAW treatment facility directly or by diverting funding.
• All three of the waste immobilization technologies per se (vitrification, grouting, steam reforming) require further research and development (R&D) to varying degrees. The time required to complete this R&D is unpredictable and, while this unpredictability was considered in the expert elicitation, it introduces uncertainty into the schedule. While grout may appear to be the most mature technology based on experience at SRS, vitrification and steam reforming have also been used in analogous settings. The differences among settings inevitably creates a level of uncertainty.
• Uncertainties remain concerning the extent to which pre-treatment will be needed to address LDR organic chemicals, LDR metals, iodine-129, and possibly other constituents. As described in the report (see Appendix A) most of the required processes will require further R&D to be ready for deployment.
• Regulatory issues introduce uncertainties into the schedules. Examples are permitting the IDF for disposal of primary and secondary treated LAW wastes, the acceptability of waste forms other than glass for disposal in the IDF, and the continued acceptability of the SLAW wastes for transport to and disposal at WCS.

The committee notes that the schedule uncertainties are likely to be biased toward being longer rather than shorter, i.e., do not count on events that would significantly reduce the schedule. The report briefly addresses schedule urgency, i.e., when decisions have to be made on which SLAW alternative to pursue. The FFRDC’s view on p. 22 of the report is: “For some [alternatives], the required time for construction and startup require an immediate start to allow completion by the required startup date” with the target startup date being 2034 based on System Plan 8. This means that delays in selecting and pursuing some alternatives would result in a commensurate increase in the startup date.

What Are the Major Programmatic Risks?

This question addresses major programmatic risks, which are defined as non-technical risks outside the control of the DOE program. In the committee’s view, the major programmatic risks are:

• Funding needs: The annual funding needs to develop, design, and build SLAW facilities, plus the future annual costs for the other components of Hanford tank waste cleanup, are estimated by the

• FFRDC to increase from the current approximately $1.3 billion per year to more than $4.5 billion per year (see p. 11 in the report). This is due to the simultaneous capital costs to complete the WTP, build the SLAW facilities, and build tank farm infrastructure to deliver wastes to the WTP. While there are significant uncertainties in the magnitude of the increase, it is clear that a substantial and possibly unrealistic increase in annual spending would be required. The cost estimates shown assume that the LAW is treated by vitrification, which is the most expensive of the three treatment alternatives. Treatment by grouting or FBSR could reduce the annual cost requirements through 2034 somewhat, but the SLAW construction cost is estimated by the FFRDC to be a significant fraction of the total annual spending requirements. The committee estimates the peak annual expenditure might be reduced by approximately $0.5 billion per year if the least expensive treatment option (grouting) were adopted. Building the necessary facilities sequentially could lower the peak funding requirements but at the cost of substantially increasing the duration and life-cycle cost of Hanford tank cleanup, as well as the increased chance of failures in tanks that are already beyond their design lifetime. Notably, the funding requirement profile in the FFRDC report does not include the annual cleanup cost for the Hanford site’s other waste legacies, such as decontamination and decommissioning of buildings, waste burial ground cleanup, and subsurface plume management, which has typically been about $1 billion per year.¹

• Waste disposal impediments: The SLAW facility plans to produce two major immobilized wastes: the SLAW in the form of glass, grout, or a steam reformed product; and grouted secondary wastes. Currently, the SLAW glass is planned to be disposed of in the IDF, and grouted SLAW and steam reformed SLAW could be disposed of at the IDF or WCS. IDF disposal is planned for grouted secondary waste generated during vitrification of the primary LAW at the WTP and the SLAW, although this grouted waste could ultimately be sent to WCS or elsewhere. However, there are existing or potential impediments to any of these plans:

  WCS is presently an operating waste disposal site that has waste acceptance criteria approved by the state of Texas. Although there are no major technical or safety issues regarding transportation to WCS, there is the potential for stakeholders in Texas or along transportation routes from Hanford to Texas to block the large-scale shipments or disposal of the waste by WCS. Thus, the committee believes that it would benefit DOE to address these stakeholder concerns early in the project.

  The IDF, a disposal facility planned for Hanford-treated SLAW and secondary waste, is presently not accepting any wastes. The IDF safety analyses and related documentation are based on vitrified SLAW and grouted secondary wastes. However, the Department of Ecology has not issued the permits required for either of these wastes. Furthermore, in multiple public meetings during the course of this study, Department of Ecology representatives have indicated resistance to considering any waste form other than glass for the SLAW, based on their belief that DOE committed to a glass waste form for the SLAW many years ago. (See the subsection on the “As Good as Glass” Conundrum in Chapter 2 of this review for details on the Department of Ecology’s most recent views.) This situation poses two impediments. The first is that primary and secondary SLAW cannot be disposed of at the IDF until the permits are issued. The second is that the Department of Ecology could decline to issue permits if decision-makers choose to treat the SLAW by grouting or FBSR. In either case, the SLAW facility would not be able to operate. Notably, the first impediment would also affect the operation of the WTP, which is planned to send vitrified LAW and grouted secondary wastes to the IDF.

Programmatic risks also include some factors outside the scope of or are not explicitly mentioned in the congressional mandate in Sec. 3134 that would affect the selection of a technology and waste form. These include:

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¹ However, in the current budget cycle, this amount has dropped to about $800 million.

• The increased chance of tanks failing (all 149 single-shell tanks have exceeded their design life);
• DOE’s proposed reinterpretation of the definition of the HLW waste could change the SLAW size and performance requirements by altering the feed volume and composition depending on how the reinterpretation is implemented; and
• DOE has also proposed expanding the Test Bed Initiative, which would have the next phase 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) (DOE-EM, 2018).

Are There Opportunities for Innovation in Hybrid SLAW Treatment Approaches?

Even during the pendency of the FFRDC report and committee review, several new opportunities for managing SLAW came to light, including the potential of the WCS facility near Andrews, Texas, and the EnergySolutions facility near Clive, Utah. These opportunities remind decision-makers that technologies and waste management options will not stand still during the decades that managing the Hanford tank waste will take, even under the most optimistic estimates. While the length of the cleanup period is undoubtedly frustrating, it also offers opportunities to learn from experience and new information to improve the effectiveness, efficiency, and possibly the speed and cost of the Hanford tank waste management effort.

In this connection, the committee observes that some of the treatment approaches may be considered to be hybrids even though only a single treatment (immobilization) process is involved. For example, treatment by grouting may require pre-treatment (processing) to destroy or remove organic chemicals to meet EPA land disposal restrictions, and additional pre-treatment to remove strontium may be cost-effective if the SLAW disposal at WCS or at the EnergySolutions facility is pursued. However, in this section, the focus is on hybrid treatment approaches involving multiple immobilization technologies, and the combination of treatment and pre-treatment options is addressed in earlier subsections on Broader Waste Management System and The Major Role of Pre-Treatment.

A hybrid approach to treating the SLAW would involve deploying more than one treatment alternative and routing a portion of liquid SLAW (e.g., from a single tank) to the alternative that is most appropriate for that particular waste composition. Thus, the advantage of hybrid approaches is that they are better able to accommodate the highly variable waste compositions in the Hanford tanks (see discussions of variability on pp. 11, 37, 93, and 109 of the FFRDC report), perhaps by routing wastes containing higher concentrations of hazardous or difficult-to-process wastes to a low-capacity but relatively expensive treatment (e.g., more extensive pre-treatment and vitrification) process and lower-hazard wastes through a high-capacity but relatively inexpensive process (e.g., grouting).

The disadvantage of a hybrid approach is that more than one process must be developed, built, and operated, which means increased system complexity as well as increased cost in what may be a cost-constrained situation. More extensive and detailed analyses based on more accurate knowledge of the composition of the wastes in the various Hanford tanks would be needed to provide adequate information to decide whether such approaches should be pursued and which alternatives to include in the hybrid approach.

It is a truism, but also an important truth, that the perfect can become the enemy of the good. The search for the one best solution can take on a life of its own, excluding other important practical or corollary considerations. This observation has particular force when the relevant timeline is very long, as at Hanford, where the most optimistic cost estimates run to many billions of dollars in capital and operating costs and the most optimistic scenarios for tank waste remediation stretch for decades. Even if one were to identify the perfect waste treatment for the SLAW today, it may appear far less than perfect in a decade or less, so leaving DOE with a sub-optimal approach and an enormous stranded investment in that approach. For example, DOE and others may learn things about that technology that render it far from perfect, or even unworkable or otherwise unacceptable. Also, fundamental improvements or new technologies may be developed that render the chosen approach and its huge fixed costs outdated. In an environment that contains many substantial uncertainties, as described in Chapters 2 and 3 of this review, it is a virtual certainty that important new information will emerge—at least some of it from experience in implementing the very decisions made today—that will call into question or alter what appeared at one time to be the best decision.

Moreover, intervening external occurrences—lower funding, further tank failures that demand urgent management, problems with other parts of an extremely complex system (waste retrieval, the HLW and the LAW, the WTP vitrification in the WTP, and the WTP pre-treatment, to mention only the most obvious)—could similarly render the selected SLAW approach redundant, undesirable, sub-optimal, or even obsolete. The longer the time between selection and completion, the more likely such scenarios are to occur.

Indeed, one could take a lesson from the Manhattan Project itself. In order to assure the production of sufficient fissile material for an atomic bomb that could be deployed before an anticipated Nazi bomb, the Manhattan Project created facilities for gaseous diffusion and electromagnetic separation to produce highly enriched uranium, and nuclear reactors coupled with a series of chemical separation processes to produce plutonium. The development of parallel tracks for waste treatment at Hanford could minimize the impact of disappointing results, which is not an unknown phenomenon in the Environmental Management program or any complex and novel engineering program; it could also maximize the likelihood that cleanup will at least proceed at some level, which is of great importance in view of the risks of tank failure. It would be extremely unrealistic to think that the nature of the Hanford tank waste easily or inexpensively lends itself to multiple treatment options; on the other hand, the uncertainty of current technologies and the length of time of the management project suggest, respectively, the need for and the opportunity to experiment with parallel, sequential, or hybrid approaches.

Could Developments Outside the Scope of This Study Affect the Use of the FFRDC’s Report and the Committee’s Review?

The report notes on p. 13 and Sec. 1.4, subsection 7, that “numerous alternative concepts for tank waste processing at Hanford have been proposed in various levels of detail, which, if adopted, could impact the SLAW assumptions used to perform this analysis. Examples include:

• Direct Feed HLW,
• At-Tank Treatment Alternatives,
• HLW Definition Clarifications, [and]
• Improved LAW glass or process models.

Any of these examples would result in direct or indirect impacts on the assumptions in this analysis. It is not possible in this study to evaluate each potential future scenario as many of the scenarios have not been defined sufficiently well to allow a definitive impact evaluation. If these scenarios progress, the impact on the SLAW mission needs to be considered.”

The committee observes that if any of these developments were to occur, the scope and scale of the SLAW treatment could be profoundly affected, and the need for treating the SLAW could be eliminated albeit at a cost of unknown magnitude and duration. The committee suggests that decision-makers view these possible developments as uncertainties to be considered when deciding how to proceed with the SLAW treatment.

THE COMMITTEE’S RECOMMENDATIONS

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 (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 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.

Organize the Report or Decisional Document Around Four Interrelated Areas

Recommendation 2-1

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

3. Determining how much and what type of pre-treatment is needed to meet regulatory requirements regarding mobile, long-lived radionuclides and hazardous chemicals, and possibly to reduce disposal costs. The congressional charge specifically mentions technetium-99 and iodine-129, but other long-lived radionuclides, such as selenium-79, may be relevant. The analysis should consider both:
   • Leaving the technetium (Tc), iodine (I), and other long-lived radionuclides in the waste form for the SLAW, with possible use of enhanced engineered barriers such as getters, which are added materials that can better retain the contaminants of concern; and
   • Removing the Tc and I (and possibly other radionuclides) to create a new waste stream with its own (and possibly different) form of immobilization and final disposition, including incorporating it into the separate vitrified HLW stream.
4. Other relevant factors. Other factors that would affect the selection of a SLAW treatment alternative include:
   • The costs and risks of delays in making decisions or funding shortfalls in terms of additional resource requirements and the increased chance of tank leaks or structural failures over time and the need to address the consequences (notably, all 149 single-shell tanks have exceeded their design life and the 28 double-shell tanks will have exceeded their design life before the waste is slated to be removed);
   • 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 of other DOE sites (e.g., the SRS) 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 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 period 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.

References

Cotton, F.A., G. Wilkinson, C.A. Murillo, and M. Bochmann. 1999. Advanced Inorganic Chemistry, 6th ed. New York: John Wiley and Sons.

Croff, A.G., and S.L. Krahn. 2015. A Simple Improved Measure of Risk from a Geologic Repository. Proceedings of the 15th International High-Level Radioactive Waste Conference, Charleston, South Carolina, April 12-16, 2015.

Darab, J.G., and P.A. Smith. 1996. The chemistry of technetium and rhenium species during low-level radioactive waste vitrification. Chemistry of Materials 8(5):1004.

DNFSB (Defense Nuclear Facilities Safety Board). 1990a. DNFSB Recommendation 90-3, “Future Monitoring Programs at Hanford’s HLW Tanks.” Federal Register Notice Vol. 55, No. 62, March 30, 1990.

DNFSB. 1990b. DNFSB Recommendation 90-7, “Implementation Plan for Recommendation 90-3 at the Department of Energy’s Hanford Site, WA.” Federal Register Notice Vol. 55, No. 202, October 18, 1990.

DOE (U.S. Department of Energy). 1988. Disposal of Hanford Defense High-Level, Transuranic, and Tank Waste, Hanford Site, Richland, Washington. Record of Decision (ROD) for DOE/EIS-0113, April 8, 1988.

DOE. 2011a. Technology Readiness Assessment Guide, DOE G 413.3-4A, September 15, 2011.

DOE. 2011b. Radioactive Waste Management Manual, DOE M 435.1-1, Change 2.

DOE. 2013. Final Tank Closure and Waste Management Environmental Impact Statement for the Hanford Site, Richland, Washington. Record of Decision. Federal Register Notice Vol. 78, No. 240, December 13, 2013.

DOE-EM (U.S. Department of Energy’s Office of Environmental Management). 2018. Hanford Test Bed Initiative. Fact Sheet and FAQ. July 2018.

DOE-ORP (U.S. Department of Energy’s Office of River Protection). 2017. River Protection Project System Plan, Revision 8, ORP-11242, Prepared for the U.S. Department of Energy’s Assistant Secretary for Environmental Management, October 2017.

Dunning, D. 2016. History of Vitrification at Hanford. Presentation to Oregon Hanford Cleanup Board. May 16, 2016.

Fuhrmann, M., and A.L. Schwartzman. 2008. Corrected Kd values for selenium. Health Physics 94(2):192.

GAO (U.S. General Accounting Office). 1991. Nuclear Waste: Pretreatment Modifications at DOE Hanford’s B Plant Should Be Stopped, Report to the Chairman, Environment, Energy, and Natural Resources Subcommittee, Committee on Government Operations, House of Representatives, GAO/RCED-91-165, June 1991.

GAO (U.S. Government Accountability Office). 2014. Hanford Cleanup: Condition of Tanks May Further Limit DOE’s Ability to Respond to Leaks and Intrusions, Report to the Honorable Ron Wyden, U.S. Senate, GAO-15-40, November 2014.

GAO. 2015. Hanford Waste Treatment: DOE Needs to Evaluate Alternatives to Recently Proposed Projects and Address Technical and Management Challenges, Report to the Committee on Armed Service, U.S. Senate, GAO-15-354, May 2015.

GAO. 2017. Nuclear Waste: Opportunities Exist to Reduce Risks and Costs by Evaluating Different Waste Treatment Approaches at Hanford, Report to Congressional Addressees, GAO-17-306, May 2017.

Helton, J.C., C.W. Hansen, and C.J. Sallaberry. 2014. Expected dose for the nominal scenario class in the 2008 performance assessment for the proposed high-level radioactive waste repository at Yucca Mountain, Nevada. Reliability Engineering and System Safety 122:267-271.

Lee, P. 2018. “Overview of the 2017 IDF Performance Assessment for LAW,” Washington River Protection Solutions, Public Meeting, Richland, Washington, February 28, 2018. http://dels.nas.edu/resources/static-assets/nrsb/miscellaneous/Hanford2/hanford8.pdf (accessed August 9, 2019).

Lukens, W., D.K. Shuh, N.C. Schroeder, and K.R. Ashley. 2004. Identification of the non-pertechnetate species in Hanford Waste Tanks, Tc(I)-carbonyl complexes. Environmental Science & Technology 38:229-233.

NASEM (National Academies of Sciences, Engineering, and Medicine). 2018a. Review of the Analysis of Supplemental Treatment Approaches of Low-Activity Waste at the Hanford Nuclear Reservation: Review #1. Washington, DC: The National Academies Press.

NASEM. 2018b. Review of the Draft Analysis of Supplemental Treatment Approaches of Low-Activity Waste at the Hanford Nuclear Reservation: Review #2. Washington, DC: The National Academies Press.

Peterson, R.A., E.C. Buck, J. Chun, R.C. Daniel, D.L. Herting, E.S. Ilton, G.J. Lumetta, and S.B. Clark. 2018. Review of the scientific understanding of radioactive waste at the U.S. DOE Hanford Site. Environmental Science & Technology 52(2):381-396.

Roberson, J. 2001. Memorandum from Assistant Secretary for Environmental Management Jessie Roberson sent a memorandum to the Director of Office of Management, Budget, and Evaluation, Department of Energy. November 14, 2001.

Sattelberger, A.P. 2005. Technetium Compounds. In Multiple Bonds Between Metal Atoms, 3rd ed. F.A. Cotton, C.A. Murillo, and R.A. Walton, editors. New York: Springer. Chapter 7.

Schroeder, N.C., S.D. Radzinski, K.R. Ashley, A.P. Truong, and P.A. Sczcepaniak. 1998. Technitium Oxidation State Adjustment for Hanford Waste Processing. In Science and Technology for Disposal of Radioactive Tank Wastes, W.W. Schulz and N.J. Lombardo, editors. New York: Plenum Press. P. 301.

Sheppard, M., and D.H. Thibault. 1990. Default soil solid/liquid partition coefficients, Kds, for four major soil types: A compendium. Health Physics 59:471-482.

WRPS (Washington River Protection Solutions). 2018. “The Tanks.” https://wrpstoc.com/tank-operations/the-tanks (accessed June 12, 2019).