The velocity dependent dissolution of spent nuclear fuel in a geologic repository

A model describing the dissolution of fission products and transuranic isotopes from spent nuclear fuel into flowing ground water has been developed. This model is divided into two parts. The first part of the model calculates the temperature within a consolidated spent fuel waste form at a given time and ground water velocity. This model was used to investigate whether water flowing at rates representative of a geological repository located at Yucca Mountain, Nevada, will cool a wasteform consisting of consolidated spent nuclear fuel pins. Time and velocity dependent temperature profiles were generated. These profiles were input into the second model, which calculates the dissolution rate of waste isotopes from a spent fuel pin. Two dissolution limiting processes were modeled; the processes are dissolution limited by the solubility limit of an isotopes in the ground water, and dissolution limited by the diffusion of waste isotopes from the interior of a spent fuel pin to the surface where dissolution can occur