Thermodynamic and kinetic modelling of iodine induced stress corrosion cracking in nuclear fuel sheathing.

摘要

Iodine induced stress corrosion cracking, I-SCC, is a recognized factor in the operation of nuclear reactors requiring the implementation of mitigation measures for the new Advanced CANDU Reactor (ACR) because of a higher burn-up and different refuelling scheme employed by the reactor design. I-SCC is believed to depend on certain factors such as iodine concentration, oxide layer type and thickness on the fuel sheath, irradiation history, metallurgical parameters related to the sheath like texture and microstructure, and the mechanical properties of zirconium alloys. This work develops a mechanistic kinetic model, accounting for the iodine chemistry and thermodynamics in the fuel-to-sheath gap, with a finite-element technique describing the mechanism of I-SCC, and its implementation using the COMSOL MultiphysicsRTM commercial software platform. This study also proposes remedies for I-SCC with suggested experimentation.