The main structural-phase states of interaction between model corium of a nuclear reactor and a sacrificial material based on Al2O3 and a lead layer

Abstract

This article presents the results of post-experimental studies of the interaction of model light water reactor corium with a candidate sacrificial material (SM) based on Al₂O₃ (corundum) and a lead layer. The purpose of the experiments was to study the features of the interaction of the sacrificial material with corium in the conditions of simulating a severe accident with core meltdown. An active interaction of corium with the sacrificial material was established as a result of the research. This is confirmed by the fact that part of the sacrificial material entered into physical and chemical interaction with the components of corium with the formation of liquid-phase reaction products and, as a result, creating different conditions for the crystallization of corium. The study of the phase composition showed that the microstructure of solidified corium in various areas after interaction with the sacrificial material is represented by a phase of the (U,Zr, …)O_2±x type with different types of crystal lattice. At the same time, the phase analysis showed a close correspondence of the composition of the solid solutions to the initial ratio of uranium and zirconium in the model corium charge. This allows us to conclude that liquid zirconium interacted with aluminum oxide during the experiment. Thus, it was concluded that the proposed sacrificial material is promising based on the results obtained and the identified features of the interaction of aluminum oxide with the lead layer and the corium of a nuclear reactor.