Neutronic design space exploration for salt-cooled reactor system based on advanced gas-cooled reactor technology

Fluoride-salt-cooled High-temperature Reactors (FHRs) offer high power densities and operating temperatures. The current paper continues to explore the possibility to leverage the knowledge gathered in the operation of British Advanced Gas-cooled Reactor (AGR) fleet to expedite the FHR deployment. The paper looks into the neutronic performance of the potential fuel assembly inside the thermal-hydraulics optimised space. Neutronic simulations were performed at Beginning of Life conditions to identify design streams that demonstrated potential for the most favourable fuel cycle economic performance and other strategic advantages such as tritium-free NaF-ZrF₄ coolant. The study identified several possible assembly configurations with favourable neutronic performance (i.e., negative coolant temperature coefficient). The designs were considered best performing where no further modification of the design parameters led to simultaneous improvement in both k_∞ and CTC. The best performing configuration contained FLiBe, uranium-carbide fuel and a small volume fraction of graphite.