Neutron-physical characteristics modeling of light water reactors critical corium slurry in water

Abstract

In this paper, the idea of modifying the benchmark by increasing effective multiplication factor value in the considered system without increasing the number of particles under consideration and fuel enrichment is discussed. The technology of data transmission, processing and comparison of the results of neutron-physical calculations using three modern codes developed in different countries and implementing the Monte Carlo method has been worked out. For the corium and water mixture parameters search, the method conventionally called the gradient descent method is used. The search method for areas of critical state corium slurry in water is described. This method can be used to justify nuclear safety in the corium extraction and transportation processes. The methodology is based on the combined use of 1-D and 3-D criticality calculations capabilities of the SCALE 6.2 program pack. Fall of corium particles in water simulation benchmark version is formulated. The possibility of using the algorithm to find the parameters of a corium and water mixture is demonstrated. This benchmark includes the critical state of corium slurry in water and assumes the use of regular structures in the formation of geometric models. The proposed version of the critical benchmark for the corium particles in water state contains 55% fuel.