Final Review of the Study on Supplemental Treatment Approaches of Low-Activity Waste at the Hanford Nuclear Reservation Review #4 (2020) / Chapter Skim
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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.
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The objective of the SLAW treatment is to ensure that the solidified wastes can be permanently disposed of in a near-surface land disposal site. Because these sites have "waste acceptance criteria," additional pre-treatment processing is sometimes required so that the final SLAW form or forms can be accepted for disposal.
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In addition, the FFRDC report notes that "the required time for construction and startup require an immediate start to allow completion by the required startup date" for some treatment alternatives, because DOE's current plan is a target date of 2034 for the SLAW treatment to begin (which is essentially the same time as the pre-treatment and HLW vitrification facilities in the WTP are scheduled to begin operations)
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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.
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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.
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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; c. 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; d.
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• 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.
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for iodine-129 and perhaps technetium-99 appears to be a key consideration in future decisions concerning the need for pretreatment to lower the concentrations of these two long-lived radionuclides and preferences for a particular waste form. This standard is based on radiation protection approaches dating from the 1950s and is no longer currently recommended by radiation protection authorities.
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A major driver of this concern is the potential hazard to drinking water and the river system, especially the Columbia River. Related to the concern about durability and waste retention of non-vitrified forms is the strongly held view among many commenters that vitrified waste forms would provide more protection for waste disposed at Hanford and is encapsulated in the saying "as good as glass." On the other hand, there is widespread interest in the potential for out-of-state disposal of non-vitrified waste forms.
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