Safety of Advanced Nuclear Fuel Cycles

Closing the nuclear fuel cycle, as studied in the frame of international programmes will be a major step in reducing the long term radiotoxicity of high level waste while optimizing the sustainability of uranium resources. The Joint Research Centre (JRC) has almost 50 years experience in safety studies associated with thermal and fast reactor fuels and corresponding reprocessing cycles. In the past, these studies were focused to a large extent on carbide and nitride compounds. Ongoing programmes are mainly dedicated to advanced oxide and metal alloy fuels bearing minor actinides (MA). Homogeneous MA recycling envisages a small addition of MA to the fuel, while heterogeneous recycling concepts include UO2-based targets and inert matrix fuels for fast and sub-critical reactor systems. The safety driven research activities cover most stages of the fuel cycle: dust-free liquid conversion processes; advanced techniques for the study (before and after irradiation) of key-safety-relevant aspects, such as thermal conductivity, mechanical properties, density, micro- and macro-structural evolution due to irradiation, phase diagrams, vapour pressure, fission product behaviour, fuel-cladding interactions, and basic properties and process investigations to assess safe and efficient aqueous and pyrometallurgical reprocessing routes. This paper highlights significant progress obtained so far and future perspectives.JRC.E.2-Hot cell