FRACTURE-MECHANICAL PROPERTIES AND NEUTRON-IRRADIATION EFFECTS OF FUEL COMPACTS FOR THE HTTR

To simulate the nuclear fuel for High Temperature Engineering Testing Reactor (HTTR), fuel compact models using SiC-kernel coated particles instead of UO2-kernel coated particles were prepared under the same co nditions as those for the real fuel compact. The mechanical and fractu re mechanics properties were studied at room temperature. The thermal shock resistance and fracture toughness for thermal stresses of the fu el compact were experimentally assessed by means of arc discharge heat ing applied at a central area of the disk specimens. These model speci mens were then neutron irradiated in the Japan Material Testing Reacto r (JMTR) for fluences up to 1.7 X 10(21) n/cm2 (E > 29 fJ) at 900-degr ees-C +/- 50-degrees-C. The effects of irradiation on a series of frac ture mechanical properties were evaluated and compared with the cases of graphite IG-110 used as the core materials in the HTTR.