Shear Punch Testing of Nuclear Materials (Materials strand project)

Supervisors: David Armstrong (University of Oxford), Hannah Wilcox (NNL) and Mike Gorley (CCFE)

With the advent of next generation nuclear power systems including GEN IV, Small Modular Reactors and Fusion Reactors there is a drive to develop a better mechanistic understanding of the effects of irradiation damage on key structural materials. Due to the expense of producing neutron irradiated samples nonstandard test methods which minimise the volume of material needed to conduct a test are being developed. Two similar and promising methods are shear punch and small punch testing, which use either a spherical cap or flat punch to push into a thin 8mm or 3mm diameter disc shaped sample. Using these methods it has been shown that mechanical properties can be measured, but much further understanding on the deformation mechanisms operating and how this compares to traditional (ASTM standard) testing is needed if they are to be adopted by industry.

This project is in collaboration with National Nuclear Lab (NNL) and UKAEA and will focus on understanding the failure mechanisms that operate during shear/small punch testing, comparing these with conventional mechanical tests and finally assessing the ability of these tests to be performed on irradiated samples. Potential materials to be studied include key steels for use in the nuclear industry including P91 which has applications for GENIV and SMR technology, 316 stainless steel which is widely used in the fission and fusion industry and legacy neutron irradiated material from decommissioned reactors, including samples with welds. The major characterisation methods used will be TEM, EBSD and SEM fractography. Due to the nature of the funding this project is only suitable for UK nationals.

This project is offered by University of Oxford. For further information please contact david.armstrong@materials.ox.ac.uk