SIMPLIFIED INELASTIC ANALYSIS METHODS APPLIED TO FAST BREEDER REACTOR CORE DESIGN

摘要

The paper starts with a review of some currently available simplified inelastic analysis methods used in elevated temperature design for evaluating plastic and thermal creep strains. The primary purpose of the paper is to investigate how these simplified methods may be applied to fast breeder reactor core design where neutron irradiation effects are significant. One of the problems discussed is irradiation induced creep and its effect on shakedown, ratcheting, and plastic cycling. Another problem is the development of swelling induced stress which is an additional loading mechanism and must be taken into account. In this respect an expression for swelling induced stress in the presence of irradiation creep is derived and a model for simplifying the stress analysis under these conditions is proposed. As an example, the effects of irradia¬tion creep and swelling induced stress on the analysis of a thin walled tube under constant internal pressure and intermittent heat fluxes, simulating a fuel pin, is presented.