Risk and Decisions About Disposition of Transuranic and High-Level Radioactive Waste (2005) / Chapter Skim
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2 Why Consider Flexibility in Disposal Options?
2 Why Consider Flexibility in Disposal Options?
Pages 37-60
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From page 37... ...
These waste types are described in detail as case studies. This chapter establishes the basis for the committee's consideration of a process that could be applied to DOE's request for alternative disposition of some HLW and TRU waste by discussing the difficulties caused by the current definitions of HLW and TRU, and by describing three waste types containing waste streams that could be candidates for alternative disposal.
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From page 38... ...
High-Level Waste is (A) the highly radioactive waste material resulting from the reprocessing of spent nuclear fuel, including liquid waste produced directly in reprocessing and any solid material derived from such liquid waste that con tains fission products in sufficient concentrations; and (B)
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From page 39... ...
The recent legislation created exemption criteria for waste in South Carolina and Idaho based on the U.S. NRC's concentration limits and performance objectives for near-surface disposal of low-level radioactive waste and requirements that the waste be treated to remove highly radioactive radionuclides "to the maximum extent practical" (see Sidebar 1.4)
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From page 40... ...
has led to the creation of a series of different waste streams. Changes in treatment technology and other factors suggest to the committee that in certain limited cases a process could be considered for reclassification and disposal of HLW and TRU waste.
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From page 41... ...
, moving to the right reflects an increase in the concentration of long-lived radionuclides of concern (e.g., americium-243) and moving 5 Saltstone is DOE's name for the cementitious waste form used at the Savannah River Site to immobilize liquid waste from processing HLW that is being sent to the vitrification plant (see discussion on Waste in HLW Tanks at the Savannah River Site below)
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From page 42... ...
Low-activity waste from the treatment of HLW at the Savannah River Site already disposed of on-site -- the Saltstone -- is at the lower left portion of the HLW boundary.7 Vitrified HLW and calcined HLW are near the upper right. The waste grouted in two tanks that were declared closed at the Savannah River Site (tanks 17 and 20)
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From page 43... ...
2.2 WASTE STREAMS THAT MAY NOT WARRANT DEEP GEOLOGIC DISPOSAL Finding 2: Some waste currently classified as TRU or HLW may not warrant disposal in a deep geologic repository, either because (1) it is infeasible to recover and dispose of every last bit of waste that might conceivably be classified as TRU or HLW or (2)
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From page 44... ...
As case studies, the committee selected three waste types that are illustrative of the reasons for considering alternatives to disposition in a deep geologic repository for some HLW and TRU: 1. They appear to include wastes that are relatively low in radioac tivity and/or hazard compared to other HLW and TRU waste that DOE manages, and perhaps could be managed in some manner other than disposition in a deep geologic repository.
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From page 45... ...
HLW Remaining in Tanks (Heels) and Low-Activity By-Products from Treatment of HLW DOE is responsible for managing and disposing of wastes from nearly 250 tanks containing HLW at the Idaho National Engineering and Environmental Laboratory, the Savannah River Site, and the Hanford Site.
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From page 46... ...
. HLW must be retrieved from the tanks and immobilized for eventual disposal in a deep geologic repository.
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From page 47... ...
Supplemental treatment options include bulk vitrification, steam reforming, 10This view was not shared by some people who spoke before the committee, most notably some of the representatives from American Indian nations. 11Because of the difficulty of removing them, current treatment plans leave the fission products technetium-99 and iodine-129 in the low-activity waste stream.
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From page 48... ...
Sidebar 2.1: Plans for Tank Wastes The generic description of DOE's plans for processing and immobilizing leads to three wastes requiring disposal: 1. HLW glass logs produced by adding glass-making materials to the high-activity waste, melting this mixture to drive off water and some volatile anions such as nitrates, and pouring the molten glass-waste mixture into stainless steel cylinders where it solidi fies, these glass logs are to be stored on-site until they can be transported to and emplaced in a geologic repository presumed to be the proposed site at Yucca Mountain, Nevada; 2.
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From page 49... ...
DOE has not selected the material that would be used to fill the Hanford tanks. Waste in HLW Tanks at the Savannah River Site The Savannah River Site (SRS)
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From page 50... ...
The plan, under which DOE has processed its HLW, as approved by the State of South Carolina, would send all of the retrievable sludge to the Defense Waste Processing Facility. Some 300,000 m3 of salt waste, made up of the supernate and saltcake dissolved in water added to the waste, containing 207 MCi of radioactivity (including 201 MCi of cesium-137, or nearly 95 percent of the site's cesium-137)
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From page 51... ...
The Savannah River Site also has had difficulty developing the chemical processes to be used in the future Salt Waste Processing Facility. After it was found that the preferred approach, an in-tank precipitation process to remove cesium, unexpectedly generated large amounts of benzene, DOE asked the National Research Council (NRC, 2000a)
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From page 52... ...
The majority of Saltstone production has not begun because the Savannah River Site so far is processing and immobilizing only the sludge from its HLW tanks, and the vast majority of the salt waste will come from processing the saltcake and supernate from the tanks. DOE has shut down all work at the Saltstone facility pending resolution of the NRDC v.
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From page 53... ...
Another is that DOE can start processing some wastes now and bring the Salt Waste Processing Facility on-line later when DOE has fully developed the technology to make the facility accomplish its design goals. Waste in HLW tanks at INEEL DOE has 11 underground tanks used for storage of liquid radioactive waste in the Idaho Nuclear Technology and Engineering Center Tank Farm at the Idaho National Engineering and Environmental Laboratory (INEEL)
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From page 54... ...
This waste which currently contains about 44 MCi of radioactivity, is to be immobilized in a form suitable for disposal in a HLW repository and then shipped out of the state for disposal. For the roughly 500 kCi of radioactivity in 3600 m3 of liquid radioactive waste remaining at the Idaho Nuclear Technology and Engineering Center tank farm (INEEL, 2004)
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From page 55... ...
. Buried TRU at INEEL The Idaho National Engineering and Environmental Laboratory contains the Radioactive Waste Management Complex (RWMC)
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From page 56... ...
also poses toxicological hazards; a small portion is fissile material, which raises criticality concerns; and it is also possible that classified waste was mistakenly disposed of, which raises security concerns, although the Rocky Flats Plant assured INEEL that this is not the case. Waste from the post-1970 period appears to have been well documented when placed in storage, and its present configuration was designed to facilitate retrieval.
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From page 57... ...
likely constitute some of the most difficult technical challenges faced by DOE with respect to TRU waste at Hanford: The 618-10 and 618-11 Burial Grounds. This summary is based on information provided to a workshop of technical experts sharing experience in dealing with buried TRU waste (Hulstrom, 2003)
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From page 58... ...
, petroleum products, and organic chemicals. The wastes believed to be in the burial grounds include spent nuclear fuel, HLW, CH and RHTRU waste (some mixed)
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From page 59... ...
Litigation over authority and agreements about waste disposition left DOE's waste disposition program with substantial uncertainty concerning the path forward. Provisions in the Defense Authorization Act of 2005 create a process for addressing HLW at the Savannah River Site and at the Idaho National Engineering and Environmental Laboratory, although many details remain to be resolved and Hanford is not affected directly by the legislation.
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From page 60... ...
60 RISK AND DECISIONS ABOUT TRU AND HLW obstacles to DOE's working with others in South Carolina and Idaho to implement the approach recommended in this report.
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