T en different methods for the extraction of tritium from the purge gas of a ceramic blanket are described and evaluated with respect to their applicability for ITER and DEMO. The methods are based on the conditions that the purge gas is composed of helium with an addition of up to 0.1 % of H 2 or 0 2 and H 2 0 to facilitate the release of tritium, and that tritium occurs in the purge gas in two main chemical forms, i.e. HT and HTO. Individual process steps of many methods are identical; in

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... icular, the application of cold traps, molecular sieve beds, and diffusors are proposed in several cases. Differences between the methods arise mainly from the ways in which various process steps are combined and from the operating conditions which are chosen with respect to temperature and pressure. Up to now, none of the methods has been demonstrated to be reliably applicable for the purge gas conditions foreseen for the operation of an ITER blanket test module (or larger ceramic blanket designssuch as for DEMO}. These conditions are characterized by very high gas flow rates and extremely low concentrations of HT and HTO. Therefore, a proposal has been made (FZK concept} which is expected to have the best potential for applicability to ITER and DEMO and to incorporate the smallest development risk. ln this concept, the extraction of tritium and excess hydrogen is accomplished by using a cold trap for freezing out HTO/H 2 0 and a 5A molecular sieve bed for the adsorption of HT/H 2 . 4. JAERI Methods (AlB) 14 5. ENEA Methods (AIB/C) 17 6. Sulzer Methods (AlB) 23 7. Conclusions: FZK Concept 28 8. References 34 Recovery of tritium from the water molecules is carried out in a secondary loop (020-Loop) which is described in the next paragraph.