Advanced shielding materials for next-generation nuclear fusion power reactors

Our communal goal of clean and sustainable energy could be met by progress in nuclear fusion technology. Depending on this is the development of improved fusion reactor shielding materials. Such materials are particularly critical for the promising spherical tokamak reactor, which is restricted in its space for neutron shielding. A class of advanced materials yielding increased attention are ceramic composites based on the carbides and borides of tungsten [1]. These materials have impressive properties compared to conventional candidate shields [2]. For example, they can be engineered to have high fracture toughness and good manufacturability due to the presence of a small volume fraction of ductile metallic binder. The binder also affords the ability to engineer oxidation resistant coatings, giving the materials impressive safety performance in accident scenarios [3].

Our lab is committed to the development of these materials for fusion power applications [1-3]. We work particularly on understanding the degradation mechanisms of these materials in extreme fusion reactor environments, including severe thermal and mechanical stresses, corrosion and irradiation. The ultimate goal of our work is to inform fusion reactor design and allow the development of materials with enhanced damage-tolerance. These aims are both critical in the eventual deployment of fusion power.

There is a vacancy in our team for an experimentalist in materials development, irradiation and mechanical properties. The applicant should have a background in materials science or show strong enthusiasm for learning the discipline. They should support collaboration in a team environment. Their project may consist of fabricating novel materials using powder processing techniques; irradiation experiments at national ion-beam irradiation facilities; and characterisation of irradiated samples. Such characterisation may include state-of-the-art micro-mechanical testing methods and electron microscopy.

The successful applicant will benefit from support by Tokamak Energy Ltd, a rapidly growing "technology pioneer" in fusion engineering. They will also benefit from interacting with a vibrant community of researchers and world-class facilities provided by the Centre for Advanced Structural Ceramics and the Centre for Nuclear Engineering.

References:
[1] S.A. Humphry-Baker et al, A candidate fusion engineering material, WC-FeCr, Scr. Mater. 155 (2018) 129-133.
[2] S.A. Humphry-Baker, George D.W. Smith, Shielding materials in the compact spherical tokamak, Philos. Trans. A. 377 (2019) 20170443.
[3] S.A. Humphry-Baker, K. Peng, W.E. Lee, Oxidation resistant tungsten carbide hardmetals, Int. J. Refract. Met. Hard Mater. 66 (2017) 135-143.

It cannot be overstated how important reducing CO2 emissions are in both electricity production for homes and industry but also in reducing road pollution by replacing petrol/diesel cars with electric cars in the next 20 years. These ambitions will require a large growth in electricity production from low carbon sources that are both reliable and secure and must include nuclear power in this energy mix. Such a future will empower the vision of a prosperous, secure nation with clean energy. To do this the UK needs more than 100 PhD level people per year to enter the nuclear industry. This CDT will impact this vision by producing 70, or more, both highly and broadly trained scientists and engineers, in nuclear power technologies, capable of leading the UK new build and decommissioning programmes for future decades. These students will have experience of international nuclear facilities e.g. ANSTO, ICN Pitesti, Oak Ridge, Mol, as well as a UK wide perspective that covers aspects of nuclear from its history, economics, policy, safety and regulation together with the technical understanding of reactor physics, thermal hydraulics, materials, fuel cycle, waste and decommissioning and new reactor designs. These individuals will have the skill set to lead the industry forward and make the UK competitive in a global new build market worth an estimated £1.2tn. Equally important is reducing the costs of future UK projects e.g. Wylfa, Sizewell C by 30%, to allow the industry and new build programme to grow, which will be worth £75bn domestically and employ tens of thousands per project.

We will deliver a series of bespoke training courses, including on-line e-learning courses, in Nuclear Fuel Cycle, Waste and Decommissioning; Policy and Regulation; Nuclear Safety Management; Materials for Reactor Systems, Innovation in Nuclear Technology; Reactor Operation and Design and Responsible Research. These courses can be used more widely than just the CDT educating students in other CDTs with a need for nuclear skills, other university courses related to nuclear energy and possibly for industry as continual professional development courses and will impact the proposed Level 8 Apprenticeship schemes the nuclear industry are pursuing to fill the high level skills gap.

The CDT will deliver world-class research in a broad field of nuclear disciplines and disseminate this work through outreach to the public and media, international conferences, published journal articles and conference proceedings. It will produce patents where appropriate and deliver impact through start-up companies, aided by Imperial Innovations, who have a track record of turning research ideas into real solutions. By working and listening to industry, and through the close relationships supervisory staff have with industrial counterparts, we can deliver projects that directly impact on the business of the sponsors and their research strategies. There is already a track record of this in the current CDT in both fission and fusion fields. For example there is a student (Richard Pearson) helping Tokamak Energy engage with new technologies as part of his PhD in the ICO CDT and as a result Tokamak Energy are offering the new CDT up to 5 studentships.

Another impact we expect is an increasing number of female students in the CDT who will impact the industry as future leaders to help the nuclear sector reach its target of 40% by 2030.
The last major impact of the CDT will be in its broadening scope from the previous CDT. The nuclear industry needs to embrace innovation in areas such as big data analytics and robotics to help it meet its cost reduction targets and the CDT will help the industry engage with these areas e.g. through the Bristol robotics hub or Big Data Institute at Imperial.

All this will be delivered at a remarkable value to both government and the industry with direct funding from industry matching the levels of investment from EPSRC.