Evaluation of alternative halide coolants for lead-cooled Generation IV fast reactors via TALYS simulations

Abstract The lead-cooled fast reactor (LFR), one of the prominent concepts among Generation IV nuclear reactors, operates with a fast neutron spectrum and utilizes molten lead or lead-bismuth eutectic as coolant. Research on Generation IV reactors has recently gained significant momentum due to the increasing need for clean and sustainable energy sources to mitigate the environmental impact of fossil fuels. In this study, alternative coolant candidates for future nuclear reactors have been explored, including mercury, iron, thallium, tin, aluminum, and ferrite. The radiative capture cross-sections [(n, γ) reactions] of selected materials – namely Pb, Hg, Fe, and Sn – were calculated using the TALYS 1.95 nuclear reaction code. Certain materials were evaluated both in their elemental forms and as halide compounds or eutectic alloys. The neutron-induced gamma production (radiative capture) cross-sections were analyzed and compared to assess the viability of these substances as potential coolants. This comparative analysis aims to identify promising candidates that could offer improved neutron economy, thermal properties, and structural compatibility for next-generation fast reactor designs.