Project title: Understanding the role of hydrogen-dislocation interactions in the corrosion and hydrogen uptake of irradiated zirconium fuel cladding alloys
Supervisor: Dr. Mark Wenman, Dr Andrew Horsfield and Professor Adrian Sutton and Carrie Miszkowska (Rolls Royce)
Zirconium alloys are predominantly used in nuclear fuel cladding. The lifetime of these alloys is limited by the pickup of hydrogen from the surrounding water coolant, and subsequent formation of hydrides. In addition to the alloy composition, the defects, dislocations and dislocation loops caused by radiation damage affect the hydrogen pickup fraction and corrosion rate. The mechanistic understanding of the interactions between hydrogen and radiation damage (especially dislocation loops) requires computational modelling techniques able to simulate thousands of atoms. The empirical potentials available at the moment for the Zr-H system (most notably EAM) do not provide sufficient accuracy, and DFT calculations are too slow for use on the system sizes required. The aim of this project is a development of DFTB (Density Functional Tight Binding) potential for the Zr-H system, where electronic structure is included explicitly. This should provide a model much faster than DFT codes, but more accurate and more transferable than empirical potentials. This will allow for modelling of hydrogen in irradiated zirconium alloys.