PhD Studentship: Radiation Induced Degradation of Advanced Tungsten Borides 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 co-funded by Tokamak Energy as part of the University’s Prosperity Partnership and will be collaborated with world-leading institutes in Germany, France and the US.

Background:

Fusion energy presents a significant opportunity for generating safe, reliable, carbon-free, and virtually endless power. Tokamak Energy, a private UK-based fusion enterprise, and the UK’s Spherical Tokamak for Energy Production (STEP) initiative, seeks to illustrate the feasibility of commercial fusion by integrating spherical tokamak with high-temperature superconducting (HTS) magnets. However, the compact design of a spherical tokamak places the fusion plasma in close proximity to a critical component known as the “centre-column,” which houses highly heat- & radiation-sensitive HTS magnets. Therefore, these magnets must be protected by spatially efficient shielding materials. These shielding materials will then themselves degrade when exposed to fusion’s extreme conditions - intense neutron exposure, temperature variations ranging from cryogenic levels to over 1000 °C, high plasma particle bombardment in plasma-facing regions and intense heat fluxes that may reach from tens of MW/m² to several GW/m² during plasma disruptions. Consequentially, the HTS magnet lifetime and, by extension the reactor lifetime, is intertwined with the lifetime of shields in a fusion environment. Currently, very little is known regarding how novel tungsten-based shielding materials will degrade when exposed to fusions irradiation environment – especially at cryogenic temperatures. Tokamak Energy has developed a new high performance proprietary material, di-tungsten pentaboride (W2B5) which promises to provide a game changing impact on shielding efficacity. However, essentially nothing is known regarding the radiation-induced microstructural evolution and thermo-mechanical degradation of W2B5 and the entire WxBy system when exposed to fusion-relevant conditions – which this PhD will reveal.

The Project:

This PhD will study the effect of fusion-relevant irradiation conditions on degradation of tungsten boride materials, with a focus on W2B5. The study will evaluate, but not limited to, the following key questions

1. Understanding the effect of cryogenic temperatures on radiation induced degradation such as crystalline to amorphous transformation, structural integrity loss etc.
2. Understanding the low- & intermediate temperature volumetric instabilities due to amorphization and anisotropic lattice parameter swelling
3. Quantifying radiation-induced micro-cracking problem and benchmarking W2B5 behaviour with other anisotropic ceramic crystal structures.

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/). This project will involve multi-national collaborators. You will specifically engage with and travel to the French National Centre for Scientific Research (CNRS) at Orsay in France to use the world-renowned JANNuS in-situ/ex-situ ion irradiation facility (https://jannus.in2p3.fr/). Additionally, you will collaborate with the University of Birmingham and Tokamak Energy’s Prosperity Partnership team, which collaborates with key fusion leading institutes such as Oak Ridge National Lab/University of Tennessee in the US and Forschungszentrum Jülich in Germany. You will work as part of team in a diverse, inclusive, multi-cultural and collaborative environment that nurtures excellence and innovation. We will provide you the mentorship you need for a prosperous post-PhD career.

Who we are looking for:

A first or upper-second-class degree in an appropriate discipline such as, materials science, engineering, physics, data science. Knowledge of fusion basics and/or microstructural characterisation would be advantageous.

Please contact Professor Arun Bhattacharya (a.bhattacharya.1@bham.ac.uk) for information enquiries, including your CV and transcripts.

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