Radiation damage of UO 2 by high-energy heavy ions

Abstract

In connection with the rim effect of high-burnup light water reactor (LWR) fuel, a series of experimental studies on the radiation damage of UO 2 was conducted by irradiation of high energy heavy ions in the order of 100 MeV. Sliced UO 2 pellets for LWR were irradiated at ambient temperatures below 200°C, with 100–300 MeV iodine and 100 MeV nickel ions over a fluence range of 2 × 10 −17 − 1.8 × 10 20 ions/m 2. The lattice parameter changes (Δa/a 0) at the surface, 100 MeV iodine and nickel irradiations were reasonably scalled by the displacement per atom (dpa), which accounted the nuclear energy deposition only. The changes, Δa/a 0, however, could not be scaled by the electronic energy deposition at the surface. In the 100–300 MeV iodine irradiation, the lattice parameter slightly increased with increasing incident ion energy. The above ersults suggest in total that the defect formation corresponding to the lattice parameter change was mainly due to the nuclear energy deposition under the present experimental conditions, with an additional contribution of the electronic energy deposition.