Study of the KV-1 facility core burnup using results of numerical simulations and gamma scanning of fuel assemblies
The paper describes a numerical simulation and experimental procedure used to study the fuel burnup in the KV - 1 facility reactor core. The study was carried out in two steps. In the first step, a detailed simulation model of the reactor was developed and simulation of the fuel burnup with representation of real core campaign was performed. The simulation results were used to calculate the pinwise power distribution and fission product buildup. In the second step, the axial distribution of 134Cs and 137Cs (reference radionuclides) activities in spent fuel assemblies was measured concurrently with out-of-reactor detection of damaged spent fuel assemblies. The key feature of the procedure is direct simulation of experiments with measurement of 134Cs and 137Cs activities, based on the pinwise calculation of fission product buildup that was carried out at the first step of the study. Direct comparison between the simulation and experiment results ensures reliable verification of the simulation model within measurement error limits. The paper presents numerical simulation and simulation model verification results against measurement results.