Nuclear fusion offers an attractive future prospect for energy production with no carbon emissions. However, a viable nuclear fusion reactor has yet to be demonstrated. One of the factors limiting the development of such a device is the hostile environment that reactor materials will be exposed to. A combination of high-energy neutron fluxes, high temperatures, large temperature gradients, thermal shocks, transient loading events, and corrosion from coolants/tritium breeding materials creates a set of conditions that will be detrimental to materials performance. Several candidate materials for various reactor components exist, but they are all limited in some capacity. The aim of this project was to use a novel alloy development approach to produce a material that may be better suited for certain fusion applications, or otherwise may be able to inform the future development of such an alloy. One potential advantage of nuclear fusion power is its relative lack of radioactive waste products compared to nuclear fission. However, this imposes a restriction on the elements used in reactor materials: they must not produce radioactive waste that is long-lived. By using elements with favourable nuclear activation properties and adopting a similar development rationale used in high entropy alloys, a set of low-activation, multi-principal component alloys were produced. The alloy systems investigated, Ti-V-Cr-Mn and V-Cr-Mn, produced a microstructure that would be favourable for fusion applications after a homogenisation treatment, in contrast to some other, highly-concentrated alloys. Furthermore, the alloys generally showed no or limited microstructural evolution after ageing at fusion relevant temperatures. This kind of behaviour is essential for any candidate fusion material. The high temperature oxidation properties of the alloys were also assessed and were found to be improved relative to other fusion candidate alloys. Resistance to oxidation has important implications for the safety case of using a given material and may also aid in manufacturing. This work has examined two virtually unexplored alloy systems and found that they may hold promise for fusion applications. Further characterisation will be required to assess whether they are truly viable candidate materials. Regardless, this work will aid in the exploration of new alloy systems and may inspire further fusion alloy development.
- nuclear fusion
- high entropy alloys
- vanadium alloys
- alloy development
The development of low-activation, multi-principal element alloys for nuclear fusion applications
Barron, P. (Author). 1 Aug 2021
Student thesis: Phd