Experience Feedback of a Pressurised Cast Stainless Steel Header Used in the Tore-Supra Tokamak

L. Doceul (Sp), J.J. Cordier, A. Durocher, F. Faisse, L. Gargiulo, P. Chappuis, CEA-Cadarache, Saint Paul lez Durance (France) 
The Tore-Supra tokamak is a fusion device in operation since 1988, its main features are its super conducting toroidal magnets and its actively cooled first wall. Tore-Supra is focused to the study of physics and technology devoted to long plasma discharge.
The major upgrade of the Tore-Supra in-vessel components, the CIEL project is in operation since 2001. The main component of this project consists in a flat toroidal pump limiter constituted of elementary high heat flux components protected by CFC flat tiles, cooled by pressurized water at 150°C and linked to a 316L SS supporting structure. This structure acts as a pressurised water manifold and as a mechanical ring (5m diameter). The whole assembly, is designed to sustain 15MW of convective power and electromagnetic loads, it must be helium tight at a pressure of 6MPa and ensure 0.1mm flatness and 0.1mm circularity accuracies.
Each sector (12 in total) of the ring (rectangular section 160mm x 160mm) is drilled by two parallel curved main collector holes (60mm diameter). The casting process was chosen to deal with such a complex design, to reduce cost and to avoid unreparable welds. This type cast stainless steel structure with build-in pressurized cooling loops is representative of some technological choices to be made in the in-vessel components of ITER.
In spite of successful tightness reception tests in the factory, during the assembly of the CIEL’s components on site, micro leaks were detected in a generic way on the sectors. This paper deals with the feed back from the manufacturing and the reparability of this 316L SS cast structure, the following items will be developed:
- Specifications associated,
- Tightness reception test,
- Problems occurring during fabrication,
- Analyse of defaults occurring in the material and weld repairing
- Alternative solutions.

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