An investigation on the 2nd irradiation test of candidated materials of uranium high-density fuels for high performance research reactors

The second irradiation test plan of uranium high-density research reactor fuels was worked out to investigate the in-reactor performance of the selected fuel materials from the 1st irradiation test using the actual operating conditions of high performance reactors. In order to raise the irradiation test temperature of fuels, the thickness of fuel meats was adjusted from 0.5 mm to 0.7 mm. The irradiation hole in ATR was chosen from ''I'' holes to 'A' holes with higher neutron flux. The fuels with various Mo contents will be loaded to find the optimum U-Mo composition. In order to better understand the effects on microstructure of fuel material, Three kinds of fuels with different microstructure controls will be included. In order to increase uranium density using the third alloying elements of transition metals, which are known to be gamma phase stabilizer, three kinds of ternary alloys will be loaded. In this test, KAERI is considered to have a leading position in a viewpoint of the largest number of 22 fuel-plates supplied by KAERI. In comparing the in-reactor performance among three kinds of fuels fabricated by ANL, CERCA, and KAERI, the atomization fuel is assumed possibly to be better that the others from the previous results. In the next irradiation test of full size fuel, KAERI is expected to act as an important role in supplying fuel powder