Leon Butterworth
Postgraduate Researcher
University of Sheffield
Co-hort year: 2024 entry
I completed my integrated masters degree in Materials Science and Engineering at the University of Sheffield in 2024. Previous to this, in the summer of 2022, I carried out a placement at the UKAEA main site in Culham, where I worked within the Metallic Materials Group at the Materials Research Facility. During this placement, and my subsequent final year project at Sheffield, I carried out a thermal ageing study upon a selection of novel reduced activation ferritic martensitic (RAFM) steels. This process taught me necessary microstructural analysis techniques using hardness testing and electron microscopy (SEM and TEM). It was also during this final year that I decided on continuing this avenue of work into a PhD, and this is when I discovered the Fusion CDT.
Within the international effort to develop the first commercially viable fusion tokamak, the development of RAFM steels is one of the most necessary and time critical areas of research. These steels stand as the primary candidate materials to be used in the construction of the breeder blanket for STEP (the UK’s Spherical Tokamak for Energy Production), due to their manufacturing scalability, promising thermal stability, utilization of nano-preciptates to diminish the effects of radiation-induced point defects, and short time-to-low-level-waste once irradiated beyond use. However, current commercial RAFM steels, such as EUROFER97, lack the required properties for operation in a future tokamak, notably unable to exhibit deformation resistance at 650 °C (the upper bound temperature that a tokamak breeder blanket is expected to experience) when continually operating under the required 14 MeV neutron flux of 5 x 1013 neutrons/cm2/second.
During my PhD, my focus will be on understanding the nanoscale precipitation behaviour of tantalum within RAFM steels, then applying this knowledge through changes in thermomechanical processing and alloy design, in order to push RAFMs towards meeting their operating requirements. This PhD is cofunded by UKAEA, through NEURONE (NEUtron iRradiatiOn of advaNced stEels), a national programme that spans industry and academia, to develop an advanced RAFM steel that meets the requirements for commercial use in a tokamak reactor, over the next four years.
