Separate management of high-heat radionuclides ({sup 90}Sr and {sup 137}Cs) from high-level waste
High-level waste (HLW) is produced from defense reprocessing and commercial reprocessing of spent nuclear fuel (SNF). It has been assumed that HLW should be disposed of as a single waste form. However, HLW contains high-heat radionuclides (HHRs) and low-heat radionuclides (LHRs), which impose different requirements on a geological repository as follows: (1) The HHRs ({sup 90}Sr and {sup 137}Cs) generate most of the heat but have short half-lives ({approximately}30 yr) with minimal requirements for long-lived waste packages; and (2) The LHRs (all other nuclides) include the long-lived radionuclides that require (a) long-lived, expensive waste packages and (b) low repository temperatures to ensure long-term performance of the repository. In HLW where the HHRs and LHRs are combined, their different disposal requirements create conflicting design objectives. to ensure long-term isolation of the LHRs, the repository temperatures must be limited to minimize the degradation of the waste form, waste package, and local geology. Long-lived waste packages are expensive; thus, the number of waste packages should be minimized. However, HHRs control repository temperature. To minimize repository temperature, the HLW must be spread over many waste packaged with significant spacing between waste packages. These different requirements suggest that there could be advantages to (a) separating HLW into HHR and LHR wastes and (b) then separately disposing of these materials. This option is described herein, assuming that the HHR and LHR wastes are disposed of in separate sections of the proposed Yucca Mountain repository.
- Research Organization:
- Oak Ridge National Lab., TN (US)
- OSTI ID:
- 20005732
- Journal Information:
- Transactions of the American Nuclear Society, Journal Name: Transactions of the American Nuclear Society Vol. 81; ISSN 0003-018X; ISSN TANSAO
- Country of Publication:
- United States
- Language:
- English
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