Fuel Behaviour After a Loss of Coolant in an Irradiated Fuel Bay

Abstract

A loss of the water in an Irradiated Fuel Bay would cause fuel bundles stored on racks to accumulate heat. When the sheath reaches sufficient temperatures, the oxidation may become a self-sustaining 'breakaway' reaction and result in a zirconium fire. This work simulates the temperature increase of a fuel bundle exposed to air with the finite element solver COMSOL®. Fresh bundles with a decay heat greater than 2kWreached transition temperatures for post-breakaway kinetics within 20-55 minutes indicating potential for fuel damage. Determining the breakaway time more accurately and scaling to ascertain the safety of racks are next steps.