The 1st Irradiation Test Results of the High Burn-up Large Grain UO2 Pellets in HANARO

The large grain UO2 pellet developed for the high burn-up PWR fuel was finished the 1st irradiation test in the HANARO since July of 2002. The large grain UO2 pellets will be irradiated up to the burn-up higher than 70 MWD/kgU. To irradiate the UO2 pellets up to the burn-up 70 MWD/kgU, it will take about 60 months. Now the 1st irradiation test for about 30 months was finished. The burn-up of the fuel rods was 33.62 MWD/kgU for the upper three fuel rods and 37.39 MWD/kgU for the lower three fuel rods, as of the June of 2005 by which the effective irradiation time is 320.6 day at the OR-4 of HANARO. These test rods were burned the lower about 9 % against target burn-up because the control rod of HANARO was operated at the lower position than analysis condition. The lower test rod assembly is loading into the new non-instrument capsule for the 2nd irradiation test and the 2nd irradiation test will be started in time