Hydrogen isotope extraction from liquid lead–lithium eutectic alloys is a critical separation challenge for liquid-metal breeder blankets in future deuterium–tritium fusion reactors. In these systems, tritium is generated and transported within a high-temperature PbLi flow and must be continuously removed to ensure fuel-cycle closure, minimize in-blanket inventory, and limit permeation losses. This review critically assesses the main technologies proposed for hydrogen isotope recovery from PbLi, including gas - liquid contactors, permeators against vacuum, liquid–vacuum contactors, and emerging membrane gas-liquid contactor concepts. The comparison is organized around the dominant separation mechanism, mass-transfer resistance, interfacial area generation, material compatibility, extraction performance, experimental validation level, scalability, and integration potential within tritium extraction and removal systems. Available evidence shows that gas-liquid contactors remain the most historically validated option, but their scale-up is constrained by multiphase hydrodynamics, gas handling, and uncertain liquid-side mass-transfer correlations. Permeators against vacuum currently offer the most favorable route for DEMO-oriented implementation because of their compactness, selectivity, and recent validation in flowing PbLi, although their performance remains strongly affected by membrane oxidation, surface recombination, PbLi-side transport, and vacuum-side limitations. Liquid-vacuum contactors and vacuum sieve tray concepts provide attractive membrane-free alternatives, but their technological maturity is limited by unresolved film or droplet stability, reabsorption, and scale-up issues. Emerging membrane gas-liquid contactors may provide process intensification by combining high interfacial area with compact equipment, but still require long-duration validation in flowing PbLi. Across all concepts, the decisive limitation is the lack of quantitatively comparable datasets obtained under representative thermal, hydraulic, chemical, and material conditions. Flexible PbLi loop facilities, including the HIXLO facility under development at ICSI Râmnicu Vâlcea, are therefore essential for identifying rate-limiting regimes, validating mass-transfer models, and benchmarking extraction technologies on a common basis.
Niculescu et al. (Fri,) studied this question.