Ten years of maintenance on Tore Supra actively cooled components

Tore Supra, the only superconducting Tokamak equipped of actively water cooled plasma facing components, has now completed 10 years of operation (1988-1998). The associated primary pressurised water cooling loop (4 MPa at 150 degreesC) is able to exhaust a 20 MW convected or radiated power during long pulses of 200 s. The first part of this paper is devoted to an inventory and analysis of the water leaks from the plasma facing and their consequences, such as the optimisation of the pressurised water loop emptying sequence. The experience gained during 10 years by maintenance operations has also led to an improvement of the water leak detection procedure, in order to identify as accurately as possible the location of the leak. The second part of the paper describes the improvements made on quality control of Plasma Facing Components during these last 10 years. Quality Control has been increased right through the technological developments and the manufacturing process of mock-up, prototypes and series production. A specific helium tightness procedure dedicated to water cooled components has been established, consists mainly of several validation tests under pressure and temperature operating conditions. Hence reliability of the components has been largely increased. (C) 2000 Elsevier Science B.V. All rights reserved.