Analysis of a Segmentation Approach to Breeder Blanket Design and the Utilisation of FLiBe as a Novel Neutron Reflector

Tritium production in a fusion reactor is a requirement for a deutrium-tritium based plasma source and the design of a lithium containing breeder blanket is essential to a closed fuel cycle in a electricity to grid style power plant. Tritium is also a rare resource currently only produced in a few fission reactors and other low output facilities. Due to the shortfall in experimental data in this area, neutronics calculations will lead the design of the first generation fusion blankets tasked with the production of the fuel. Without such maximised breeding potential, the start up time of reactors may need to be postponed due to a low global inventory of tritium. Within this study a description of an optimisation design process which segments an EU-DEMO style blanket to provide freedom in material allocation, along with the necessary validation steps required for repeatable results. This segmented blanket is used within OpenMC to test the performance of a hybrid liquid metal and molten salt breeder. Molten salts are proposed as a possible lithium source in a fusion environment. The presentation will highlight how FLiBe can be used as a novel reflector due to its ability to breed tritium and reflect lower energy neutron back to the bulk of the breeding section. This indicates that TBR can be improved with differing material configurations rather than more conventional, single breeding methods providing optimum solutions that allow for more cost effective, and compact, blanket region while maintaining high TBR values.