High-temperature Mechanical Analysis of Discharge Pipeline of Pressurizer

Abstract

The severe accident is the beyond basis design accident due to several initial faults. The discharge pipeline of pressurizer is mainly used for pressure relief and evacuation of hydrogen in the primary circuit in severe accident. It can reduce the possibility of high-pressure core melt and the explosion of hydrogen. But in severe accident, the highest temperature of gas in the pipeline can reach 1200℃, which far exceeds the design temperature of pressurized water reactor. So it may cause the buckling or rupture of the pipeline. The pipeline may loss its discharge function. In this passage, we study the resistance of the discharge pipeline to high temperature in severe accident from the aspects of severe accident situation, high-temperature mechanical properties of pipeline material, the temperature field and stress of the pipeline, the evaluation of the stress and so on. In order to demonstrate the function of a certain nuclear power plant discharge pipeline, RCC-MR which is suitable for the high-temperature evaluation, is choose to evaluate the stress, the creep and the buckling of the pipeline. The results of the evaluation show that the discharge pipeline in this nuclear power plant can meet the functional requirements in the severe accidents.