JRC testing facilities and experimental tools for study of radiation damage

Most of the properties of nuclear fuels are modified during their reactor irradiation due to the numerous fissions and thermal gradient. The safe operation of nuclear fuels especially in abnormal conditions or to increased burnups to optimize their economics and environmental impact requires a thorough knowledge of their in-reactor aging. The formation of radiation damage is a complex process due to the nature of the different sources like fission fragments, alpha-decaying actinides or beta-decaying fission products. Single effect studies to tackle specifically radiation damage effects from these different sources are performed using ion-implantations but also doping with radioactive elements. The effect of radiation damage on the thermal-conductivity degradation of nuclear fuel could be demonstrated using UO2 samples doped with 238Pu.. The microstructure evolution of the nuclear fuel towards the high burnup structure could be partly explain by ion- implantation studies. Aging of waste conditioning matrices like zirconolite or pyrochlore has been accelerated by doping these ceramics with 244Cm or 238Pu. Characterization tools like Transmission or Scanning Electron Microscopy, X-ray diffraction, thermal diffusivity or heat capacity measurement have been used on irradiated fuel samples as well as on doped or ion irradiated samples to study the elastic or inelastic energy losses and their effect in various type of ceramics.