EU DEMO CRYOGENIC SYSTEM AND CRYODISTRIBUTION Pre-conceptual design for an optimal cooling of the superconducting magnets and the thermal shields
Résumé
With the construction of ITER in progress, the European demonstrator of a fusion reactor plant (EU DEMO) would be a device with lies between ITER and a commercial power plant able to demonstrate the production of electricity and the operation in a closed fuel cycle. CEA has been involved in the EU DEMO pre-conceptual design of the superconducting magnets, of the cryogenic system and the cryo-distribution. In the framework of the EUROfusion collaboration, significant engineering and technological results have come out and paved the way towards the conceptual design of the cryogenic users and the associated cooling system. The nominal design parameters of the cryogenic system for the superconducting magnets at around 4.5 K, for the High Temperature Superconducting Current Leads at about 50 K and for the thermal shields at about 80 K, have been varied (temperature, pressure, mass flows) to study their impact on the refrigerator concept and the helium distribution to the cryogenic users. This design methodology, which was not conducted for previous cryogenic systems (K-STAR, JT-60SA, ITER), is an innovative approach to find an optimized process. It relies on the interactions between designers, cryogenic experts and industry to explore potential ways to optimize the overall cryo-magnetic system including the superconducting magnets and the thermal shields. The preliminary specifications of the future cryogenic system and the cryodistribution have led to the estimation of the overall refrigeration requirement of around 100 kW equivalent at 4.5 K. After trade-off studies on several process options, one baseline solution has been detailed, using a novel pre-cooling refrigeration with a He-Ne mixed gas cycle. This option enables a potential gain in terms of efficiency of about 5% compared to conventional helium process of large cryoplants. The maturity of the technologies and the R&D strategy are discussed with industry.
Domaines
Sciences de l'ingénieur [physics]Origine | Fichiers produits par l'(les) auteur(s) |
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