Design Improvement of Reactor Internals Lift Rigs for Shin-Kori Nuclear Power Plant Units 3 4

摘要

The designs of Optimized Power Plant 1000 (OPR1000) reactor internals lift rigassemblies (RILR) include all necessary functions to handle OPR1000 reactor internals. The RILR, however, is composed of relatively flexible members such as channel arms, tie rods and clevis nuts which make difficult to assemble. The design improvements present a simplification of RILR and explanatory features of design changes followed by structural integrity evaluation. The cross-bracing structure of OPR1000 RILR is replaced by a series of rigid channel rings to simplify its structure. The design simplification of RILR gives the manufacturer a simple process to assemble RILR. The response spectrum analysis was performed in order to evaluate the support reactions and the stress levels of the improved RILR under safe shutdown earthquake (SSE) loading condition. The RILR was modeled with three dimensional beam element, which analyzed the lift rig with the control element assembly support plate lowered and the supports bolted down position. The results of seismic response spectrum analysis and sizing analysis were satisfied with requirement of KEPIC and the improved model can be incorporated standard shapes of RILR SKN units 3 & 4