Nuclear thermal design of high temperature gas-cooled reactor with SiC/C mixed matrix fuel compacts - 18410

Japan Atomic Energy Agency (JAEA) has started R and D on SiC/C mixed matrix fuel element of high temperature gas-cooled reactors (HTGRs) to improve oxidation resistance of fuel. Nuclear thermal design of HTGR with SiC/C mixed matrix fuel compacts was carried out as a part of above R and Ds. Nuclear thermal design was carried out based on a small sized HTGR for developing countries, HTR50S, which thermal power is 50 MW and burn-up period is 2 years. Maximum enrichment of uranium is set to be 10 wt%, because coated fuel particles with 10 wt% uranium have been fabricated in Japan. Numbers of kinds of enrichment and burnable poisons (BPs) were set to be same as those of original HTR50S (3 and 2, respectively). We succeeded in nuclear thermal design of a small sized HTGR which performance was equivalent to original HTR50S, with SiC/C mixed matrix fuel compacts. Based on nuclear thermal design, intactness of coated fuel particles was evaluated to against internal pressure increase by burnup. It was shown that intactness was kept for burnup condition of HTR50S. (authors)