Dynamic Analysis of LOFT Reactor Flow Skirt/Core Filler Assembly for LOCA + SSE

摘要

A detailed dynamic analysis of the LOFT reactor core support structures was performed to determine the ability of the flow skirt/core filler and hold-down springs to withstand Loss-of-Coolant Accident (LOCA) plus Safe Shutdown Earthquake (SSE) loadings. A double-ended offset shear occurring in 15 msec (5 msec break time + msec for offset to occur) in the intact loop at the reactor vessel nozzle provided the basis for LOCA loads. The flow skirt/core filler and lower core support structure separate from the core barrel approximately 0.068 in. as a result of the hot leg LOCA. This small displacement and the resulting impact loads produce stresses in the springs, core barrel, flow skirt/core filler, and shear pins within allowables as specified in Section III of the ASME Code for faulted conditions. (ERA citation 04:003372)