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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 A). 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 A. The Statement of Task for the National Academies of Sciences, Engineering, and Medicine’s (the National Academies’) committee is in Appendix B.

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:

Congress should consider specifically authorizing DOE to classify Hanford’s supplemental LAW based on risk, consistent with existing regulatory authorities … [and] that DOE develop updated information on the performance of treating LAW with alternate methods, such as grout, before it selects an approach for treating supplemental LAW. (GAO, 2017)

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 C. 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.

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

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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.

TABLE 1-2 Study Schedule

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 D 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 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

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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 recommendaton 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

B Plant’s embedded pipes did not comply with DOE design criteria and concluded that the pipes would be almost impossible to replace. This study also pointed out that B Plant process tanks did not comply with federal double containment requirements and, recommended that DOE request a variance from the regulator to permit the use of these tanks for pre-treatment. A January 1990 study, directed by DOE Richland [Operations Office], concluded that the problem with the process tanks remained unresolved. (GAO, 1991)

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 B). 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.