Seismic Test Results of the Main Steam Isolation Valve for Japanese Boiling Water Reactor Nuclear Power Plants

Abstract

The functional requirements of Main Steam Isolation Valves (MSIVs) provided in the Boiling Water Reactor (BWR) nuclear power plants in Japan have been previously evaluated via seismic tests and so forth. However, since the response acceleration has increased in line with a recent reassessment of standard earthquake ground motions, it is necessary to evaluate seismic operability with respect to high acceleration. In addition, from the viewpoint of equipment fragility in seismic PRA, it is necessary to determine practical seismic operability limits. We used a resonant shaking table in the Central Research Institute of the Electric Power Industry (CRIEPI), which is capable of seismic tests at acceleration levels previously unachievable, and in seismic tests carried out on an MSIV, we obtained results confirming that validated seismic operability was possible even at response accelerations as high as 15 × 9.8 m/s2. The seismic operability results obtained for this MSIV will be applied to a fragility analysis of seismic PRA.