Development of the fuel behavior analysis code for mechanical fuel cladding failure during reactivity insertion event in pwr

Pellet-Cladding Mechanical Interaction (PCMI) failure is the one of failure mode which must be evaluated in the nuclear fuel safety. PCMI is caused by the mechanical load to cladding due to the fuel pellet expansion. Under the high fuel burnup condition, the fuel cladding may become degraded by embrittlement under the neutron-induced irradiation and hydrogen accumulation due to the waterside corrosion. In order to consider the further deterioration of the material with higher burnup, the evaluation using mechanical indicators, e.g. strain and stress, might be required. In this study, a transient model is developed, which can mechanistically evaluate the PCMI behavior, in particular, for fuel rods under the higher burnup condition. The model is incorporated in a fuel behavior analysis code and verified by benchmarks with other similar codes. The PCMI predictability of this code is validated using the experimental test data.