Nanoindentation testing of high burn-up fast reactor mixed oxide fuel

Abstract

Continued research into the mechanical properties of nuclear fuel is necessary to improve modeling of the pellet-cladding mechanical interactions that occur in nuclear reactors during operation. Small scale mechanical testing with focused ion beam equipment can provide a means to study the mechanical properties of irradiated nuclear fuels by measuring their mechanical properties on minute volumes of material. In this work, room temperature nanoindentation measured the hardness and Young's modulus of fast reactor mixed oxide (MOX) fuel irradiated to 183 GWd/tHM. The hardness of the MOX fuel had a measured value of 11.2 ± 0.4 GPa. The Young's modulus of the MOX fuel had a value of 158 ± 6 GPa. The measured hardness and Young's modulus are discussed in the context of the available literature data. In addition, pathways toward elevated temperature testing and other mechanical properties are proposed.