Seismic analysis of fuelling machine bridge, carriage and column assembly of 500 MWe PHWR (in unclamped conditions)

摘要

This report deals with the seismic qualification of fuelling machine (FM) bridge, carriage and column assembly of 500 MWe Pressurised Heavy Water Reactors (PHWRs). FM bridge carriage and column assembly along with the fuelling machine head (FMH) performs the important task of on-power refuelling which is an essential feature of all PHWRs. Two fuelling machine heads home on to the opposite ends of a coolant channel to perform the refuelling operation. It is essential to refuel 2 channels for a full power day of a reactor. The fuelling machine can clamp onto 392 possible channel locations for a 500 MWe reactor. Hence it becomes very important to seismically qualify the fuelling machine since it becomes part of the pressure boundary during refuelling process. Because of the close proximity of FMH to the channels, it becomes necessary to seismically qualify the fuelling machine even in the unclamped condition. Present report gives the analysis for the uncoupled condition of FMH under both operating base earth quake (OBE) and safe shut-down earthquake (SSE) conditions using the response spectrum method. Based on the analysis it has been found that the components of FM bridge, carriage and column assembly can withstand the seismic forces generated and the stresses are within their allowable limits both under OBE and SSE loadings. This report gives in detail the input data used, mathematical modelling various boundary conditions, results and the conclusions arrived at. (author). 12 refs., 7 tabs., 14 figs., ills. (Atomindex citation 27:063112)