Test Method for Seismic Qualification of Equipment

All Category I nuclear power plant equipment must be tested or analyzed or both, for seismic qualification, that is both realistic and simple to perform. The use of floor spectra as a basis for testing procedures satisfies neither of these criteria. An alternate procedure is suggested which is based on the power spectral density concept. A discrete amplitude spectrum is derived from an assumed shape of the ground motion power spectrum and modal properties of the structure in which the equipment resides. The amplitude spectrum specifies the frequencies and amplitudes of the sinusoidal input motion to the equipment. Two methods of testing are available: (1) the sinusoids can be combined into one random motion; and (2) a sweep over the sinusoids can be made. Universal equipment certification can be made by running an upper-bound conservative test. The advantages of this method are: (1)dynamic properties of equipment are not required; (2) no post-processing of the amplitude spectrum is required; and (3) no time history analysis is needed.