Effect of radiation damage on bwr core-shroud cracking

摘要

A model is presented that estimates the effect of radiation damage on stress corrosion cracking (SCC),resulting from microstructural evolution induced by irradiation.The model is based on the Ford-Andresen film -rupture and slip -dissolution model and on hte observation that the crack propagationrate increases as the mateiral hardens.The model relates the neutron and gamma exposure to the irradiation hardening and consequent increase in the crack tip strain rate.A chemical rate theory model was empolyed to deccribe the evolution of microstructure in stainless steel leading to radiation hardening.The increase in yield stress can be corelated to an increase in the crack tip strain rate,and thus to SCC behavior.This approach was used to evaluate the effects of irradiation hardenign on core shroud cracking.The results show that hardening can have a substantial effect on core shroud cracking.