Response of Two Nuclear Power Plant Valves to Dynamic Excitation

Abstract

To formulate more suitable testing criteria for safety-related equipment in nuclear power plants, new investigations of equipment behavior under dynamic loading are required. Currently used guidelines and their applicability are summarized and several major problems to be solved by new investigations are described. Experimental and analytical studies conducted on two typical valves exemplify the type of investigation required. A 4-in. and 6-in. globe valve were investigated to determine characteristic structural dynamic-response relationships among various magnitudes of swept-sine, sine-dwell, random, and shock excitation. Different directions of acceleration were applied to each type of excitation. Finite element models of the valves were used to determine the dominant eigenvalues and eigenvectors. The experimental measurements were analyzed by the introduction of suitable dimensionless response parameters and appropriate excitation intensity measures that clearly indicate the presence of nonlinear response phenomena. Some guidelines are given for the qualifications testing of similar equipment and some areas of concern are pointed out.