Importance of Scenario Development in Meeting 40 CFR Part 191

摘要

Scenario development and screening is a fundamental part of performance assessment, but its importance in satisfying a standard is sometimes underestimated. The first step in scenario development in support of performance assessment for the standard's containment requirements is to identify a set of potentially disruptive events and processes. This set must be broad enough to allow the identification, as required by the standard, of those processes and events that might affect the disposal system; data can then be collected on the scenarios identified in this step. The standard also requires that releases be estimated for all significant processes and events; thus the final step in scenario development is systematically screening the scenarios, on the basis of their probabilities and consequences, to select those that are important enough to be modeled in detail. In general, a few hundred scenarios for the release of radionuclides from a nuclear-waste repository can be identified, but only a few of these can or should be modeled in detail. Without a description of the broad suite of scenarios that were originally considered, the regulator and the public would have difficulty in determining whether consequence modeling has been carried out for the appropriate processes and events. 17 refs. (ERA citation 13:021108)