Combined Effects of Light Gas and Damage Accumulation in Beryllium

Lead Research Organisation: University of Huddersfield
Department Name: Sch of Computing and Engineering

Abstract

Beryllium has applications in various environments which will (or already do) expose it to radiation which will result in the accumulation of helium gas and cause the displacement of atoms from their crystal lattice sites. Beryllium will be the material facing the plasma in the ITER magnetic-confinement nuclear fusion reactor currently under construction in France and titanium beryllide is being developed for use in the "pebble bed" design concept for the tritium-breeding blanket of the DEMO power plant which will follow ITER. In high-energy accelerator research, beryllium is being considered for components in proton-driven particle sources where it will experience even higher rates of helium accumulation than in nuclear fusion environments.

This project will explore the effects of gas accumulation and displacement damage in beryllium and titanium beryllide using transmission electron microscopy with in-situ ion irradiation to simultaneously observe the microstructure whilst bombarding with an ion beam. By varying the temperature, ratio of gas implantation to atomic displacement rates and the irradiation dose, this project will build up a three-dimensional matrix of experimental data.

Changes in the microstructure of a material determine how the performance of components change under the extreme environments described above. Therefore, these results will allow the ways in which the microstructure evolves under these conditions to be better understood and thus support the development of these important technologies.

Planned Impact

Economic and societal impact of an increased understanding of the microstructural evolution of beryllium due to the accumulation of displacement damage and gas atoms will be made through the realisation of commercial energy generation from nuclear fusion. The barriers to viable fusion power are largely the materials challenges and so this project will be an important step along that journey.

This will have impact for the power industry by providing a route they can take to a secure, reliable, clean, sustainable, low-carbon electricity supply. In doing so, it will be highly disruptive to the existing hydrocarbon-based energy sector - the shrinking of which will have dramatic impact on our net carbon emissions.

The economic impact of this will be felt not only on the supply side but also by energy consumers both industrial and domestic. The aforementioned characteristics of electricity from nuclear fusion will ensure ample provision in an otherwise uncertain future whilst enabling us to fulfil our responsibilities to reduce our carbon emissions and avert the more acute consequences of human-driven global warming. This will deliver economic gains by powering industrial growth and societal benefits by meeting the energy requirements of modernity with increasing quality of life.

Further economic impact will be achieved by supporting the development of nuclear fusion technology here in the UK which can then be exported around the world. This project will not only generate knowledge in the UK but also add to the skills base to enable this area to expand.

Beyond avoiding the worst ravages of climate change, the natural world will also gain from the impacts described above through reduced harmful activities required to extract fossil fuels including mining, drilling and fracking. Consequently, as well as benefiting the planet, society will enjoy a greener better-protected world in which to live.
 
Description Titanium and chromium beryllides, TiBe12 and CrBe12, are materials of potential future importance as neutron multipliers for tritium breeding in nuclear fusion reactors. Understanding how these materials will perform in the extreme environments associated with such applications is key to their successful deployment. The conditions they will face include irradiation resulting in the displacement of atoms and the accumulation of helium gas inside the materials whilst being exposed to elevated temperatures.

The project has explored the microstructural evolution of these materials to help in developing such understanding. This has included detailed characterisation of defects known as "bubbles" and "faults" which were found to be induced under irradiation at temperatures of 600°C and 900°C.
Exploitation Route The insights into the microstructural evolution of these materials will enable others to advance these materials upwards on the Technological Readiness Level scale.

Within academia, this will help researchers exploring the fundamental response and performance of beryllides under extreme conditions typical of nuclear environments.

Beyond this, engineers and scientists working to realise the goal of clean energy from nuclear fusion will be better equipped to design and develop the systems required to "breed" the tritium which is essential to the operation of these reactors but otherwise not readily accessible in nature in insufficient quantities.
Sectors Energy