PhD Studentship: Interfacial Interactions Between Fusion Structural Materials & Tungsten-based Shielding Ceramics in Extreme Environments for Spherical Tokamak Centre-column Shields

A 3.5-year UK PhD studentship is available at the University of Birmingham with a tax-free stipend. The project is collaborated with world-leading institutes and private fusion: Tokamak Energy, Forschungszentrum Jülich in Germany, CNRS-Orsay in France, and Oak Ridge National Lab/University of Tennessee in the US.

Background:

Spherical Tokamaks (ST) combined with high-temperature superconducting (HTS) magnet technology is emerging as a key commercial fusion solution promising pilot plant concepts that can be deployed by the 2040s. Tokamak Energy, a leading private fusion company in the UK and the UK Atomic Energy Authority’s STEP pilot plant programme are both based on a spherical tokamak concept. A key challenge with STs is its limited volume that brings the fusion plasma closer its life-limiting “centre-column” component, which houses the highly sensitive high temperature superconducting (HTS) magnets. HTS being susceptible to damage from neutron irradiation and heat means they must be protected by spatially efficient shielding materials – which are largely based on the tungsten carbide WxCy and/or WxBy tungsten boride systems. Such shields also require metallic support and/or cooling structures enforcing several metal-ceramic interfaces. While the ceramic shield choices are fairly limited, the support or cooling structures can range from a variety of metallic alloys – with leading candidates being austenitic steels, reduced activation ferritic-martensitic steels or vanadium alloys. Regardless of which metallic structure is down selected, a key degradation mechanism in the shield configuration is anticipated to be physical- and chemical interaction at the interfaces/joints under the effects of accelerated diffusion under irradiation, high temperature and high heat flux – the knowledge of which is currently largely missing in the fusion community.

The Project:

This PhD project will evaluate the effect of high temperature, irradiation, high-heat flux and thermo-mechanical stress on microstructural, physical and chemical degradation of metal-ceramic interfaces and/or joints envisaged in the Tokamak Energy’s centre-column shield design. Using long-term thermal ageing, mechanical loading, irradiation testing and high heat flux testing, the study will focus on the following key questions:
(i) Understanding chemical interactions at high temperatures and stress between WxCy and WxBy ceramic shields, and metallic support/cooling structures.
(ii) Understanding the microstructural evolution of metal-ceramic interfaces under irradiation.
(iii) Mapping metal-ceramic interface failure when exposed to steady-state (up to ~50 MW/m2) and transient heat loads (>1 GW/m2) via high heat flux testing.

Supervision and International Collaborations:

You will be based at the University of Birmingham and will be co-supervised by industry leaders from Tokamak Energy (https://tokamakenergy.com/ ). You will have access to state-of-the-art facilities at the university, at the industry partner and with several partnering institutions worldwide. This project will involve multi-national collaborators, and so you will have a unique opportunity to engage with fusion leaders from Forschungszentrum Jülich in Germany, Oak Ridge National Lab/University of Tennessee in the US and CNRS-Orsay in France. You will also interface with key industrial material manufacturers to provide experimental data for improving manufacturing processes.

Who we are looking for:

A first or upper-second-class degree in an appropriate discipline such as, materials science and engineering, nuclear engineering, fusion energy, chemical engineering, physics, or mechanical engineering. No prior experience is mandatory. Some knowledge of fusion basics and/or microstructural characterisation would be advantageous. A driven individual with an inquisitive mind.

Contact:

Informal inquiries should be sent to Professor Arun Bhattacharya (a.bhattacharya.1@bham.ac.uk ). Please include your CV and transcripts.