PIRAT - An analytical tool for reliability assessment of reactivity control systems - Progress and applications to Sodium Fast Reactors

Overview & Synopsis

Reactivity Control Systems (RCS) are essential safety components for nuclear reactors. One of the most dicult situations these systems experience is seismic motion due to the large deformation and crucial responsibility to shutdown the reactor.This paper introduces a new method for dynamic modeling that accounts for the contact and free motion of the mobile part of the RCS with the guiding sleeve. The new method introduces springs with a gap to account for material interaction. This method is implemented into the DEBSE solver within PIRAT, a toolbox currently in development for RCS design. The work presented in this paper explores the dynamic eects on a model (tentatively representative) system to investigate the assumptions made in some previous works using a quasi-static simulation. Based on the frequency of excitation, various responses are seen that are not captured in the quasi-static simulations. This work gives evidence tothe importance of the dynamic modeling of RCS.