Acceptance criteria considerations for miscellaneous wastes
EPA standards set forth limitations regarding releases to the accessible environment adjacent to a geologic repository. The NRC criteria pertaining to waste form and engineered barrier performance place certain restrictions on the physical and chemical nature of the waste form and require substantially complete confinement of radioactivity until the high-heat-production period is past. After this period, the annual release of radionuclides from the waste package is normally limited to 1 part in 100,000 of the amounts calculated to be present at 1000-y decay. The regulation permits deviation from these criteria in exceptional circumstances. One such circumstance might be the absence of a significant perturbation in temperature around the stored waste. The lack of significant heat release will eliminate the hydrologic driving force for dispersal of radionuclides. Exceptional circumstances which potentially could justify a less stringent long-term release criterion are: small quantity of radioactivity, the nature of the radioactive species, and the nature of the geology in which the waste is to be emplaced. Because the MW after a suitable decay period have low heat release rates per unit volume, they apparently could be so emplaced in a repository that there would be no compelling need, according to the reasoning presented in 10 CFR 60, for a 1000-y container. Regarding attainment of the specified long-term release rate criterion, neither the solubility limits for the various waste forms nor the conductance of potential migration barriers are currently adequately characterized. The relatively small total heat generation rate for the MW in combination with the usual low volumetric heat generation rate apparently will allow application of migration barriers in a low temperature environment where barrier performance would be expected to be unchanged with time.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 6897076
- Report Number(s):
- CONF-870306-9; ON: DE87005343
- Resource Relation:
- Conference: Waste management '87, Tucson, AZ, USA, 1 Mar 1987; Other Information: Portions of this document are illegible in microfiche products
- Country of Publication:
- United States
- Language:
- English
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