Influence of cladding on linear elastic RPV-analysis during loss of coolant accident

Abstract

This report is dealing with the influence of the cladding layer on linear elastic fracture mechanics analyses of reactor pressure vessels subjected to emergency core cooling situations. The American computer code OCA-I was modified in order to be able to solve the stress distribution produced by thermal and mechanical loading across an undisturbed cylinder wall which is composed of two different materials. A brief description of the analytical approach is given. Analyses of two typical loss-of-coolant accidents, the Large Break LOCA and the Small Break LOCA, in which long axial cracks have been assumed to exist prior to the transient were performed. The results are presented in form of comparisons between calculations without considering cladding effects, with thermal cladding effects included only, and with cladding accounted for in thermal as well as in stress analyses.