Validation of TRACE Simulation of Small-Break LOCA Test (SB-CL-18) in the Large-Scale Test Facility

Abstract To evaluate the safety of a nuclear power plant, several accident sequences including design basis accidents are calculated using a plant simulation code, and the performance of the safety measures of the plant is evaluated according to whether it satisfies safety criteria. To demonstrate that these calculations using the simulation code are valid, it is important to validate both the simulation code and the input data. We present our approach to PWR accident analysis based on simulations of a small-break LOCA test (SB-CL-18) in the Large-Scale Test Facility (LSTF) using the three-dimensional thermal hydraulics simulation code TRACE. To show the applicability of TRACE to small-break LOCA, the simulation of the SB-CL-18 was carried out using TRACE and the simulation results were compared with the measurements for several parameters. Furthermore, the loop seal clearing phenomenon that occurs in small-break LOCAs was investigated through a detailed analysis of measured data and TRACE simulation results.