The proposed research will accelerate the development of advanced ceramic breeder materials for compact spherical tokamaks. As the limiting step in the tritium recovery process for solid breeders is tritium release from the crystal, this proposal will examine the atomic scale mechanisms responsible for tritium diffusion in a leading candidate ceramic, building on successful previous work.
An understanding of the tritium mobility will enable the development of strategies to limit tritium retention, thereby ensuring maximum tritium production to sustain the plasma. The subtle interactions between tritium atoms and defects present in the ceramic matrix will ultimately determine the rate of tritium release from the crystal. However, the nature of the defects in the material will change as the material ages and so it is critical that we understand the tritium release process across the material’s lifetime.
Development of ceramic breeder materials for ITER and DEMO has focused on two key candidate materials, lithium metatitanate (Li2TiO3) and lithium orthosilicate (Li4SiO4). However, recent work has indicated that the high lithium density and excellent tritium release characteristics (at least in the stoichiometric material) mean that octalithium plumbate (Li8PbO6) is an interesting possible replacement for Li2TiO3 and Li4SiO4 for use in spherical tokamaks.
Therefore, this study will employ a mixture of atomistic simulation techniques (DFT and MD) to explore tritium release in Li8PbO6. The project will develop a tritium release model for Li8PbO6 similar to fission gas release models used in fission reactors.
CDT name: GREENCDT
The programme is funded by EPSRC, industrial partners and participating institutions