Can small scale mechanical test data be used for structure critical design?' is it in collaboration with Culham Centre for Fusion Energy (CCFE) and my

Lead Research Organisation: University of Sheffield
Department Name: Materials Science and Engineering


This PhD project will investigate the effect of helium on the diffusion of hydrogen (used as an analogue for tritium), in Li-containing ceramic materials, and develop a conceptual model of helium bubble formation and thermal evolution. Li-ceramics are candidates for the tritium breeder blanket material surrounding a fusion reactor core, in which tritium is produced by the transmutation of lithium following capture of a fusion neutron. The production of tritium also results in the formation of helium atoms. This project will investigate whether, at predicted breeder blanket operating temperatures, helium atoms will agglomerate to form helium bubbles; helium bubbles preferentially nucleate at grain boundaries or at intrinsic defects; and if bubble formation and evolution is dependant on material microstructure and composition. The second part of the project will investigate if helium atoms/bubbles act as trapping sites for hydrogen, reducing hydrogen diffusion. If hydrogen retention is found to increase due to the interaction of helium, this could have implications for tritium diffusion. Reduction in tritium diffusion would reduce efficiency and affect the life-time of the breeder blanket. Candidate Li-ceramics will be produced by, for example, solid-state synthesis. Ion implantation will be used to incorporate helium and hydrogen into selected materials and material microstructure and ion implantation induced defects characterised by XRD, SEM/EDX and TEM. The effect of helium atoms/bubbles on hydrogen diffusion will be investigated using thermal desorption spectroscopy (TDS). This research will develop our fundamental understanding of gas ion interactions in ceramics, which is also relevant to nuclear fission applications e.g. the accommodation of fission gasses in nuclear fuels, and accommodation of helium in actinide containing ceramic wasteforms


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Studentship Projects

Project Reference Relationship Related To Start End Student Name
EP/P510634/1 01/10/2016 30/09/2021
1815976 Studentship EP/P510634/1 26/09/2016 25/12/2020 Victoria Brown
Description In general, small-scale testing cannot be used to measure the properties of bulk materials. This is a problem in the nuclear industry as there is often a very limited amount of material available for testing. By using finite element simulation in conjunction with small punch test data, it is possible to predict the macro scale plastic properties of a material.
Exploitation Route By using the method developed it may be possible to use it on new/untested materials. It would also be possible to further develop it to take into account sample defects and/or non-standard sample geometries.
Sectors Construction,Energy,Manufacturing, including Industrial Biotechology,Other