Technical Implications of Aging Used Fuel Prior to Emplacement in a Deep Geologic Repository

Abstract

Delaying the disposal of used CANDU fuel can reduce the plan area and excavated volume of a deep geologic repository, and therefore the cost, because the decreased thermal power from radioactive decay would allow containers to be placed closer together. Potential negative effects of reducing the repository size include the increase in duration of elevated long-term temperatures for the used- fuel containers and the decreased structural stability of the excavations from the increased long-term thermal load. First, the factors affecting repository cost as a function of heat distribution and heat transfer are presented. Then the potential negative effects are discussed.