Sensitivity Analysis of Safety Injection Tanks for LOCA scenarios

Abstract

The Safety Injection Tank (SIT) is a main component of the emergency core cooling system in the APR1400. It passively injects borated water into the system due to pressure difference in accident scenarios. A system analysis was done altering parameters that affect the performance of the safety injection tank. The SIT functions based on its initial conditions. Pressure and water level are the two factors that may be altered; the pressure loss coefficients are affected by the initial conditions. Therefore, a total of four factors can be altered for analysis: pressure, water level, high flow loss coefficient, low flow loss coefficient. Using Latin Hypercube Sampling, we can sample the cases to be examined more efficiently. With these samples, the APR1400 is analyzed for a Loss Of Coolant Accident (LOCA) scenario. MARS-KS code is used for the system analysis. Regulations require that the pressure and water level of the APR1400 to be maintained within a certain band at all times. Calculation results show that within the band, the system integrity stays intact for LBLOCA scenarios. However, we may further test the case for various scenarios and can find what factors affect the system integrity the most in various LOCA scenarios. This can become the basis for regulations regarding the SITs.