Enabling sustainable fusion fuel cycles: A comparative life-cycle assessment of emerging tritium extraction and removal technologies for liquid lithium systems

Sustaining deuterium–tritium (D–T) fusion systems critically depends on the ability to continuously recover and recycle tritium through a closed fuel cycle. Because tritium is scarce, in-situ breeding combined with tritium extraction and removal (TER) is a prerequisite for tritium self-sufficiency and, consequently, for the practical deployment of fusion power. The viability of fusion as a large-scale low-carbon energy source will therefore depend not only on plasma performance, but also on the efficiency, scalability, and environmental performance of TER systems. Despite their critical role, the energy requirements and environmental implications of TER technologies remain insufficiently characterized across breeder-blanket and tritium-carrier concepts. At the same time, existing life cycle assessment (LCA) studies of fusion energy are typically conducted at a highly aggregated level, limiting insight into how subsystem-level fuel-cycle configurations and engineering decisions influence overall environmental performance. Here, we present the first comparative cradle-to-gate LCA of four representative TER technologies for liquid lithium systems: Maroni oxidation, Maroni electrolysis, direct Li/T electrolysis, and the distillation column. Using a functional unit of 1 kg of tritium recovered, we evaluate each technology under alternative electricity-supply scenarios and plausible parameter cases to explore uncertainty associated with emerging TER technologies. The results reveal substantial variation in CO 2 -equivalent impact, cumulative energy demand, and material-resource indicators across TER pathways, showing that subsystem design choices shape the environmental performance of future fusion fuel cycles. These findings provide insights into environmental hotspots and sensitivity to key assumptions, supporting early-stage R&D prioritization and future system-level LCAs of fusion fuel cycles.