Licensing a geologic repository: Types of uncertainties

Abstract

This paper provides a summary of the regulatory background for the U.S. geologic repository program, describing the history of the congressional actions that established the program and the allocation of responsibilities within the program. The current status of actions by the U.S. Department of Energy (DOE) to investigate a potential repository site, located at Yucca Mountain in Nye County, Nevada, is then reviewed. The U.S. Nuclear Regulatory Commission has provided guidance to the DOE for characterizing potential repository sites, and the DOE's approach to implementing that guidance is described. One of the purposes of intensive characterization of a potential repository site is to reduce uncertainties about key aspects of the site that are relevant to protection of public health and safety. However, the link between measurable site characteristics and demonstrations of compliance with regulatory criteria promulgated by the responsible federal agencies are often complex. A discussion of types of uncertainties points out that the potential licensee (DOE) and the regulator (NRC) may have differing views of the nature and importance of uncertainties.