3
Report Strengths
The final federally funded research and development center (FFRDC) report has been through many iterations in response to the present National Academies committee’s reviews and the preceding consensus studies (NASEM, 2020, 2022a, b). The FFRDC responded constructively to all of the committee’s recommendations and suggestions and took most of them into account. The technical rigor and clarity of the presentation of the ideas in the report have greatly improved over the course of the iterative process, an approach that could serve as a model for other challenging programs and analyses. The appendices in the FFRDC report contain detailed and careful analysis of technical factors related to the different processes that are analyzed at a high level, and the logic presented in the report for the down-selection to the processes subjected to more detailed analysis is clear.
As discussed above, the FFRDC identified six major considerations (“decision forming criteria”) that should determine the decision on the treatment and disposal of low-activity waste (LAW). However, responding in part to comments by the committee and as previously mentioned in this review, the FFRDC chose not to include the fifth and sixth criteria (regulatory approval and public acceptance) in their comparative analysis of options, citing their inherent unpredictability from a technical perspective. Instead, FFRDC treated them as “uncertainties,” which are described (in the case of regulatory standards, in considerable detail) but not otherwise considered in the comparison. This National Academies review refers to the remaining criteria (1-4) as “technical.”
Finding 8. The result of the iterative process is a stronger report that will be useful to decision makers in understanding the issues and trade-offs and ultimately determining how and where the supplemental low-activity waste (SLAW) will be managed. It has gathered together a great deal of relevant technical material from a variety of domains in one place.
Finding 9. The FFRDC has made a strong technical case (1) that off-site disposal of grout is for the most part a valid option, and may be a technically valid option with on-site disposal, depending on the results of a performance assessment for the on-site disposal facility; (2) that there is a clear and persistent difference between grout and the other two alternatives (vitrification and fluidized bed steam reforming [FBSR]) on virtually all technical criteria that the FFRDC evaluated; and (3) that grout dominates the other two alternatives on the basis of cost and time to operational start-up.
Finding 10. The committee notes multiple studies that have been done to demonstrate that the FBSR product is as stable as vitrification and has equivalent immobilization of the radionuclides (NASEM, 2020, 2022b). The
FFRDC report notes the same: that FBSR is less expensive than vitrification but has a much higher technical risk than grout or vitrification in the context of Hanford SLAW. On this basis the FFRDC concludes that that FBSR is not an attractive alternative for treating Hanford SLAW. The committee agree with the FFRDC assessment on this point based on the evidence given.
Finding 11. The FFRDC has made a technical case that grout treatment and disposal of SLAW could occur at locations other than the Hanford site—and in various combinations of function, location, and time (e.g., Grout 4B)—and thus articulated a clear rationale for disposing off-site if that is the choice of the relevant decision makers. The addition to the analysis of off-site treatment and/or disposal has created a new set of SLAW options for decision makers, noting the off-site locations do not reside near potable water or above aquifers.
Finding 12. The FFRDC recommendation, based on the importance of speed, flexibility, and cost in the disposition of SLAW, recognizes that time both is and is not a friend. It is not a friend in the sense that the longer the cleanup process goes on, the greater the risks (worker and public exposure, accidents, leaks, etc.) and costs. At the same time, it recognizes the value of time in allowing multiple pathways for resilience (NASEM, 2022b) and that a decades-long program offers opportunities for learning and the deployment of new technologies (NASEM, 2022a, b).
Finding 13. The analysis of the extent to which organic chemicals subject to land disposal restrictions could impede the use of grout is a valuable addition to the assessment of on-site disposal because it touches on something that will have a significant role in seeking regulatory approval of grout.
Finding 14. Volume 2, Appendix I of the FFRDC report provides an excellent overview of the regulatory issues for SLAW, especially when used in conjunction with Appendix J, which is the detailed position of the Washington State Department of Ecology. However, as FFRDC emphasizes, Appendix I does not attempt predictions about actual approval of specific options, the permitting process, and other aspects of regulatory approval.
Finding 15. The Conclusions and Recommendation section of the FFRDC report is a helpful guide to the significance of the details in the main body of the report and its appendices. This section also improves the transparency of the report, in that it clearly sets out the inferences that the FFRDC team has drawn from their analysis. (As stated above, however, assessment or endorsement of the substance of the recommendation is beyond the scope of the National Academies committee’s Statement of Task.)
Recommendation B. DOE faces many uncertainties inherent in decisions with long-term completion horizons, challenging materials, complex technology, evolving technology, and an unpredictable regulatory and stakeholder environment. Under these circumstances, it should emphasize flexibility in its overall approach, allowing for multiple, redundant options and pathways, as well as the ability to change over time. (Grout 6 is an example of such an approach because it allows for changes in treatment and disposal location during the long-term mission.)
