Seismic Response Spectrum Analysis on Advanced PWR Coolant System

The pressure boundary of reactor coolant system (RCS) consists of reactor vessel, pressurizer, steam generators, coolant pumps, main pipes and other crucial equipments. During operating, the RCS and its equipments withstand mechanical loads, pressure fluctuations, even earthquakes and other extreme loads, which shows that the vibration characteristics and seismic response are significant for the safe operation. In this paper, the RCS of advanced passive pressurized water reactor (PWR) is studied. The three-dimension finite element model, consisting of one reactor vessel, pressurizer, two steam generators and four coolant pumps, is constructed to simulate the seismic response. Based on modal analysis, the deformation and stress response of RCS under Safety Shutdown Earthquake (SSE) loads is analyzed under three orthogonal directions with multi-angle. In each case, the two horizontal input spectra are rotated on z axis with 30 degrees. The variation of seismic response with spectrum input angle shows the best and worst orientation for anti-earthquake and provides basis for the design, installation and improvement of RCS. Moreover, compared with static analysis of RCS, the stress under extreme condition is linearized and assessed with ASME standards. The result shows that all the values satisfy the stress criteria and the structure and material of the RCS meet the design requirements. More work on the parameters sensitivity analysis will be done in further study.