The stresses applied in the butterfly valve were calculated under a combined load, that is, an equivalent static force, defined as Grade D by the KEPIC MFA.
The procedure for response spectrum analysis is provided in the KEPIC END .
The structural analysis that was used to estimate the responses of stress took into account all three load conditions suggested in the KEPIC MFA, that is, RRS (required response spectrum), DRS (design response spectrum), and RIM (required input motion).
In this study, the structural safety analysis of a 200A butterfly valve for use in a nuclear power plant was performed in static and dynamic ways according to the KEPIC MFA.
These values were under the allowable strength for the materials used in the manufacture of the butterfly valve, and, therefore, its structural safety met the requirements of the KEPIC MFA.
 M-16 KEPIC MFA, Qualification of Mechanical Equipment-General Requirements, Korea Electric Power Industry Code, 2010.
 E-5 KEPIC END, Nuclear Electrical and I&C--Equipment Qualification, Korea Electric Power Industry Code, 2010.