Development of Coupled Simulations for Critical Dual Purpose Canisters in a Saturated Repository

Abstract

This report details ongoing work in the development of simulations and techniques for critical dual-purpose canisters (DPCs) in a saturated repository with a focus on canisters that reach an equilibrium at a low, quasi-steady state power level that could be sustained for thousands of years. This report describes an effort to expand the initial methodology for predicting the quasi-static power level for individual DPCs to the entire inventory of spent fuel currently captured by the UNF-ST&DARDS database. Efforts using high fidelity computational fluid dynamics results to verify the accuracy of RELAP5-3D for critical DPCs is also presented. Finally, this report describes ongoing work performing high-fidelity CFD simulations to verify a RELAP5-3D modeling methodology for two-phase boiling inside DPCs. This appears to be the most promising approach for expanding the analysis of critical DPCs beyond those that reach steady-state conditions in a saturated repository prior to boiling.