Preclosure seismic hazards and their impact on site suitability of Yucca Mountain, Nevada

This paper presents an overview of the preclosure seismic hazards and the influence of these hazards on determining the suitability of Yucca Mountain as a national high-level nuclear-waste repository. Geologic data, engineering analyses, and regulatory guidelines must be examined collectively to assess this suitability. An environmental assessment for Yucca Mountain, written in 1986, compiled and evaluated the existing tectonic data and presented arguments to satisfy, in part, the regulatory requirements that must be met if the Yucca Mountain site is to become a national waste repository. Analyses have been performed in the past five years that better quantify the local seismic hazards and the possibility that these hazards could lead to release of radionuclides to the environment. The results from these analyses increase the confidence in the ability of Yucca Mountain and the facilities that may be built there to function satisfactorily in their role as a waste repository. Uncertainties remain, however, primarily in the input parameters and boundary conditions for the models that were used to complete the analyses. These models must be validated and uncertainties reduced before Yucca Mountain can qualify as a viable high-level nuclear waste repository.