Seismic Qualification of the Unconventional Valve by Shake Table Testing

Abstract

To make Nuclear Power Plants (NPP) more acceptable by the public, there is a need to conform to the stringent safety criteria evolved continuously. Among the several safety aspects, the seismically induced effects call more attention at the present scenario. But the adequate full scale testing of the critical components can render a more realistic simulation. Extensively shake table testing is used for the seismic qualification and research purposes. It provides the means to excite structures in such a way that they are subjected to conditions representative of true earthquake ground motions. The seismic qualification tests were conducted as per the test procedure given in IEEE STD 344-1987 standards: IEEE recommended practice for seismic qualification of class 1E equipment for Nuclear Power Generating Station. Valves are one of the active components in the SFR system. The seismic operability of active components can be established only by shake table testing. Shake table testing includes fixing of the equipment into the shake table, exiting the table with a seismic excitation equal to or larger than the design earthquake, resonance search test in all the three directions for 1 to 50 Hz to identify the system frequencies and assessment of the functionality and structural integrity of the valve during and at the end of the test. The valve that has been experimentally qualified completed type test for OBE & SSE cycles, the same will not be utilized in the reactor application. The methodology involved in the seismic qualification of the unconventional valve presented in this paper. Among the various shake table experiments carried out for the seismic qualification unconventional valves, the experiment carried out for the Inclined Fuel Transfer Machine (IFTM) Gate valve is referred in this paper for the above purpose. It is one of the unconventional type large in size and heavy gate valve available in the SFR system