Structural aspect of corium spill on VVER-1000 reactor pit floor slab

Abstract

This paper provides a brief but pointed description of the possibly neglected structural aspect of corium spill on the concrete floor slab of the reactor pit. The corium-concrete interaction is by now a well-studied phenomenon which is considered the key parameter for determining the ablation rate in the floor slab. What has not been reported in the literature so far is the effect of the progressing ablation, the extremely high temperature and the uneven thermal gradient on the static performance of the reinforced concrete floor slab. It was discovered that the structural considerations lead to a different mode of failure as well as to much faster progress of the expected collapse of the reactor pit floor slab.