Post-irradiation examinations and high-temperature tests on undoped large-grain UO2 discs

摘要

Within the Nuclear Fuel Industry Research (NFIR) programme, several fuel variants -in the form of thin circular discs - were irradiated in the Halden Boiling Water Reactor (HBWR) at burn-ups up to similar to 100 GWd/t(HM). The design of the fuel assembly was similar to that used in other HBWR programmes: the assembly contained several rods with fuel discs sandwiched between Mo discs, which limited temperature differences within each fuel disc. One such variant was made of large-grain UO2 discs (3D grain size = similar to 45 mu m) which were subjected to three burn-ups: 42, 72 and 96 GWd/t(HM).