[3O09-12] Reactor Design and Seismic Evaluation

[3O12] Effect of Bi-Directional Excitation on Scrammability

*Yugo Hyotani¹, Yoshihiro Goto¹ (1. HGNE)

Keywords:scram, scrammability, bi-directional excitation, aseismic engineering, numerical analysis

Boling Water Reactor (BWR) has the safety shutdown function to automatically insert Control Rods (CRs) into reactor cores at large seismic events. Evaluation of seismic scrammability, which means CR insertability at seismic events, is one of the most important design criteria for ensuring seismic safety of BWR. It is estimated that contact behavior between fuel assemblies and a CR in case of seismic input in two horizontal directions can be different from that in case of seismic input in one horizontal direction, which would affect scram time.
In this study, we compared the relationships between trajectories of fuel assembly and the scram time by inputting pares of sine waves in two horizontal directions using a numerical analysis technology that evaluates the scrammability of BWR.