MSRE 계통 및 설비 내 핵분열생성물 거동 예비 평가

Abstract

A preliminary analysis of the Molten Salt Reactor Experiment (MSRE) facility, a key test site for molten salt reactor technology, was conducted to evaluate the behavior of fission products during a hypothetical accident scenario using the MELCOR code. The MSRE, an experimental molten salt nuclear reactor, operated at Oak Ridge National Laboratory (ORNL) in the U.S. from 1965 to 1969. In this study, several variables that can change under accident conditions in nuclear power plants were selected, and a sensitivity analysis was performed to assess aerosol concentrations in the containment based on these variables. The key variables analyzed included aerosol properties (such as diameter, concentration, and density), the failure time of the reactor vessel pressure boundary, and the deposition area within the containment. The analysis revealed that aerosol concentration and size within the containment were influenced by the failure time of the reactor vessel boundary. Furthermore, a delayed rupture of the boundary resulted in fission products from the reactor core depositing on the heat exchanger, leading to an increase in the exchanger's temperature and a heightened risk of its failure. Additionally, it was observed that an increase in the deposition area within the containment led to a reduction in airborne fission product aerosols, and containment gas temperatures were lower compared to other scenarios. These findings are expected to serve as foundational data for future accident management strategies, specifically when determining the optimal opening time and area for the reactor vessel's pressure relief valve.