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Management of Commercially Generated Radioactive Waste - U.S. ...

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5.23<br />

sorption properties (for fission products and actinides), to significantly reduce radionu-<br />

clide migration through the backfill barriers.(a) The capability <strong>of</strong> the backfill materials<br />

to prevent or delay ground-water flow through the backfill is also being evaluated. Other<br />

properties <strong>of</strong> interest being evaluated (Neretnieks 1977 and Nowak 1979) are thermal conduc-<br />

tivity, mechanical support strength, swelling, plastic flow, and forms and methods for<br />

emplacements (DOE Statement <strong>of</strong> Position to NRC (DOE/1980).<br />

5.2.3 Repository System<br />

The repository system will provide for the receipt, inspection, transfer to the under-<br />

ground, emplacement, and containment after closure <strong>of</strong> radioactive wastes. Performance cri-<br />

teria stipulating the minimum acceptable behavior for an engineered system are required in<br />

evaluation <strong>of</strong> the design. Criteria for the performance <strong>of</strong> the mined repository during the<br />

operational phase have not yet been established; however, such criteria are expected to be<br />

similar to those for other nuclear packaging and storage facilities.<br />

The surface facilities <strong>of</strong> a repository are similar to those now used in the nuclear<br />

industry. Radiation protection practices in the repository, therefore, will be similar to<br />

those used in other nuclear facilities and are not discussed here. Repository support<br />

facilities and underground workings are also similar in many ways to those common to the<br />

mining industry. Therefore, issues not uniquely related to radioactive waste repositories,<br />

such as the construction <strong>of</strong> support facilities, are not discussed here.<br />

For the purpose <strong>of</strong> assessing the long-term containment and isolation integrity <strong>of</strong> a<br />

geologic repository, disruption phenomena which represent potential waste release mechanisms<br />

have been postulated. This analysis is discussed in detail in Section 5.5. Existing stud-<br />

ies show no compelling environmental reasons, including public health, that should preclude<br />

disposal <strong>of</strong> waste in deep geologic repositories.<br />

Other scenarios and variations <strong>of</strong> the scenarios presented in this Statement have been<br />

analyzed and published (Claiborne and Gera 1974). The conclusions <strong>of</strong> the published studies<br />

are in agreement with those provided above. However, this is a complex and extensive area<br />

<strong>of</strong> ongoing research which is generally being examined by scenario analysis, study <strong>of</strong> waste<br />

form release rate and radionuclide transport phenomena, and consequence analysis. Specific<br />

R&D projects in risk assessment are listed in Appendix L.<br />

Discussion <strong>of</strong> potential adverse impacts <strong>of</strong> constructing and operating a repository<br />

will be limited to the following factors:<br />

* Excavation and underground development<br />

* Thermal effects<br />

* Radiation effects<br />

* Repository penetrations.<br />

(a) Such materials are sometimes referred to as "getters" due to their ability to retard the<br />

movement <strong>of</strong> certain materials.

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