多目的高温ガス実験炉の炉床部黒鉛ブロック間に生じるすき間と流れに関する試験

Abstract

In order to minimize the leak flow rate of an experimental VHTR (a multi-purpose very hightemperature gas-cooled reactor), the graphite blocks are tightened to reduce the gap distance between blocks by core restrainers surrounded outside of the fixed reflectors of the bottom-core structure and seal elements are placed in the gaps.By using a 1/2.75-scale model of the bottom-core structure, the experiments on the following items have been carried out: a relationship between core restraint force and block gap, a relationship between core restraint force and inclined angle of the model, leak flow characteristics of seal elements etc.The conclusions derived from the experiments are as follows:(1) Core restraint force is significantly effective for decreasing the gap distance between hot plenum blocks, but ineffective for the gap between hot plenum block and fixed reflector.(2) Graphite seal element reduces the leak flow rate from the top surface of hot plenum block into plenum region to one-third.