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 A). 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

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 requiements 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:

1. Selection of a technology that will produce an effective waste form. This has two parts:
   • The treatment (immobilization) technology:
     • How well will it work? Is the technology well understood, tested or used under real-world conditions, dependent on other technologies, or relatively simple?
     • What types and volumes of secondary waste are created by each technology?
     • What is the lifetime cost and duration and uncertainties therein?
     • What are the risks (e.g., programmatic and safety) and uncertainties therein?
   • The waste forms and associated disposal sites:
     • How effective is each waste form in immobilizing the waste (e.g., the materials science of the incorporation, corrosion, and release processes) and over what time periods?
     • What is their performance under the expected disposal conditions (e.g., release from the disposal facility and transport through the geosphere to a receptor)?
     • How do the waste form performances actually differ? This goes further than simply demonstrating compliance, but rather demonstrates an understanding of how the waste forms and disposal environments actually interact.
2. Selection among available disposal sites. The report describes the IDF and WCS, and it briefly mentions the EnergySolutions facility near Clive, Utah. Selection requires an understanding of how each site will “work” over time in providing a barrier to the release and migration rate of key radionuclides, especially and specifically technetium-99 and iodine-129.
   • What is the role of the hydrogeology at each site (the IDF and WCS) in preventing/slowing radionuclide release and migration?
   • How might the disposal facility design be modified to enhance the performance of each waste form?

Important site related-issues include regulatory compliance, public acceptance, cost, safety, expected radiation dose to the maximally exposed individual over time, and differences among the disposal environments.

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.