Seismic response of gas-cooled fast breeder reactor core structural assembly via modal synthesis

Abstract

An investigation has been conducted to determine theoretically the dynamic response of the GCFR core support structural assembly when subjected to boundary excitation from seismic disturbances. The system analyzed consists of a thick grid plate to which many core elements are vertically attached. The dynamic problem was solved by synthesizing component modes of two substructures and treating them as continuous subsystems. The investigation is of practical significance in the sense that the radial responses of the core elements in axisymmetric motions cause reactivity change of the core, and therefore an accurate assessment of the dynamic response of the system is important to the core and core support structure design. Numerical system modal data and time-history response results are presented.