SPENT NUCLEAR FUEL SEPARATIONS AND TRANSMUTATION CRITERIA FOR BENEFIT TO A GEOLOGIC REPOSITORY

This paper describes the results to date from an ongoing study to establish the chemical separations and transmutation criteria for commercial spent nuclear fuel that would be of benefit to a geologic repository, as measured by the allowable reduction in repository size for a given capacity. The bases for determining the chemical elements to be separated are described, and include both thermal and dose rate criteria. The benefit to a repository is quantified as a function of the separation of certain chemical elements and the efficiency of the chemical separation, along with subsequent transmutation of some of the chemical elements. The proposed repository at Yucca Mountain is used as an example of a geologic repository for the purposes of illustrating the magnitude of the benefits that are possible and the implications for repository size and operation. This work is being done in support of the U.S. Department of Energy Advanced Fuel Cycle Initiative, where numerous reactor, processing, and recycling strategies are being examined to determine the impact on issues important to the viability of nuclear electricity generation, including the impact on the disposal of spent nuclear fuel and nuclear waste.