Uranium silicide exists in many phases, and has some properties that are attractive for fuel materials: most notably a high density and high thermal conductivity. These properties prompted irradiations in some research reactors, where significant swelling at higher burnups was observed. This is highly undesirable, and interest in the material waned. However, attention has recently focussed on the U3Si2 phase, which has not previously been widely studied because it occupies a very small region in the phase diagram and was thought to be difficult to manufacture. Early work at Manchester and elsewhere has shown that manufacture of this phase can be achieved without undue difficulty, and that it has attractive properties as a potential fuel material. The purpose of this Task is to explore the effects of manufacturing parameters on the properties of U3Si2 fuel pellets, using a range of microstructural, compositional, and thermo-physical characterisation techniques. In addition, we plan to undertake testing of the pellets, focussing on their resistance to reactions with steam under conditions representative of a failed fuel rod. If resources permit, ion beam irradiation of pellet samples will be undertaken at DCF in order to explore the resilience of the microstructure to protons (as an analogue for neutrons) and heavy ions that are representative of fission products.
Accident Tolerant Fuels in Recycling
