Seismic Test Results of Air-Operated Valve Actuators for Nuclear Power Plants (Air-Operated Butterfly Valve (Direct-Coupled Type))

The functional requirements of air-operated valves provided in nuclear power plants during an earthquake 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 functional maintenance with respect to high acceleration. It is also necessary to determine practical functionality from the viewpoint of equipment fragility in seismic Probability Risk Assessment (PRA) Here, we used a resonant shaking table (see Ref. [1]) in the Central Research Institute of the Electric Power Industry (CRIEPI), which is capable of seismic tests at acceleration levels that have been unachievable until now. From the results of seismic tests on air-operated valve actuators, the operability of active components used with an existing design was confirmed to be more than 15 × 9.8 m/s2 (horizontal directions (X and Y)) and more than 20 × 9.8 m/s2 (vertical direction (Z)).