Simulation of Branch Pipes Fracture Condition in Low-Pressure Safety Injection System of PWR. Issue 1 (1st February 2023) - Deng, Chunyin
Abstract: In the low-pressure injection system (LHSI) of the PWR unit, two branch pipes of the recirculation pipeline are vulnerable to fracture during minimal-flow operation. Flowmaster was used to create a hydraulic model for the LHSI minimal-flow operation and to simulate the branch double-end shear fracture condition in order to predict the leakage flow volume and the water level drop rate of the refueling water storage tank (RWST) in order to analyze the impact of branch pipe fracture on the water leakage of the RWST. According to the study results, there is very little deviation between the operating condition of the system as it actually is and the Flowmaster model, and the leakage volume following branch pipe fracture is considerably less than that of the RWST. Leakage volume per minute is around 0.025% of the RWST's overall volume, which has negligible influence on the unit's safety. Based on the results of the simulation, this study suggests LHSI system operation recommendations.