Fusion Programme - ENEA - Fusione

3. Technology Programme2007 Progress Report1×10 -9Apparent permeability (A m -1 s -1 Pa-1/2)Post oxidation app. permeabilityPermeability1×10 -101×10 -11Real permeability (mol m -1 s -1 Pa-1/2)1×10 -12 0/3 150/3 300/3 450/3 600/3 750/3 900/3 1050/3Ratio H 2 /H 2 OFig. 3.12 - Permeability of hydrogen through Inconel 718 for different H 2 /H 2 O ratiostimes (here 1-2 h). The focus will now be on Incoloy 800 HT, which is one of the reference materials forhigh-performance steam generators.The tritium extraction system (TES) and coolant purification system (CPS) are theConceptual design principal auxiliary circuits in any type of TBM to be tested in ITER. In the HCPBof auxiliary systems TBM, the main functions of the TES are to extract tritium from the lithiated ceramicfor HCPB-TBM breeder by gas purging, remove it from the purge gas and route it to the ITERtritium plant for its final recovery. The CPS has to process part of the TBM Hecoolant stream in order to remove tritium permeated from the TBM, removeincondensable impurities, and control the He chemistry.A preliminary design of both systems was proposed, starting from determination of the expected gascomposition at the TES and CPS inlet during the different ITER operational phases and taking into accountthe main requirements of ITER and TBM experimentation: small space and flexibility in operation. Thedesign included a 3D layout for a first assessment of the space required for installation of the systems onITER.For the TES, having considered and compared different technologies (cold traps, adsorption systems,selective membranes, getter beds), the proposed process consists essentially of an adsorption column,filled with a microporous material (zeolite or other) and operated at room temperature, for Q 2 O removal,and a temperature swing adsorption (TSA) system, operated at LN2 temperature in the adsorption phase,for Q 2 removal. The adsorption column for Q 2 O removal has been dimensioned to be substituted just aftera six-day back-to-back pulse series. The TSA is able to remove and deliver continuously all Q 2 extractedfrom the purge gas to the downstream ITER tritium systems. The process also contains a by-pass linewhich houses a U (or other metallic) getter, used as a scavenger bed. This means that the TSA system canbe excluded when, for example, only isolated standard pulses are foreseen and a relatively small amountof Q 2 has to be extracted, or during the TSA system maintenance.Part of the system, up to and inclusive of the adsorption column for Q 2 O removal, has to be placed in theport cell, while the downstream part, with the Q2-TSA, should be located in a suitable glove box in thetritium building. The estimated space needed in the port cell is 2.4×1.4×1.0 (L×W×H) m 3 and 2.0×1.4×2.5(L×W×H) m 3 in the tritium plant building.The CPS has been dimensioned to process 7 Nm 3 /h of He, corresponding to 0.025% of the total He mass49