Study on the Smoothness of the Flow Channel of Rapid Pressure Relief Pipeline in Severe Accident of HPR 1000

Both pipelines and the equipment experience extreme high temperature and pressure in sever accident of the nuclear power plant. As the only way to relieve pressure in case of severe accident, it is very important to ensure the smoothness of the flow channel of rapid pressures relief pipeline. In this paper, the study on the smoothness of the flow channel of rapid pressure relief pipeline in severe accident of HPR 1000 is carried out. Heat transfer analysis is done for rapid pressure relief pipeline and pressurizer in severe accident. The temperature changes of pipeline and pressurizer are obtained. The deformation process of rapid pressure relief pipeline in severe accident is simulated by elastic analysis method. The relationship between temperature and deformation is obtained. The 3D model is established, and the material non-linearity is introduced. The simulation study on the position of spring support and damper of rapid pressure relief pipeline is carried out, and the status of spring support and damper of pipeline under severe accident is obtained. The influence of high temperature creep on pipeline integrity is analyzed for the case of temperature higher than 450℃. 10 positions with the largest deformation on the rapid pressures relief pipeline are selected to study the residual area of the pipeline section, and the minimum residual area ratio and the minimum flow area of the pipeline under severe accidents are obtained. The research results show that the flow channel of the rapid pressures relief pipeline can still ensure the smoothness under the severe accident of HPR 1000, and the rapid pressures relief pipeline of HPR 1000 can ensure that the reactor core will not melt.