Power deposition and margins on the Tore Supra pump limiter and fabrication of the high heat flux components

Abstract A complete toroidal pump limiter (TPL) is being built at Tore Supra. This limiter will cover 7.5 m2 of the bottom part in the vacuum inner vessel. It will be composed of 574 elementary high heat flux components facing the plasma, named fingers. Below the limiter in the pumping throat, 48 other fingers are positioned as neutraliser elements. All the fingers, made of CuCrZr alloy, are actively cooled by pressurised water and covered with carbon fiber composite (CFC). The limiter is designed to remove continuously (1000 s) a convective power of 15 MW and to exhaust a particle flow up to 4 Pa m3/s. The power deposition on all the elements of this limiter was predicted using the TOKAFLU code developed by CEA and taking into account the self-shadowing of the limiter. The heat flux on the standard finger remains below 10 MW/m2 whereas it reaches up to a peaked value of 15 MW/m2 for some neutraliser fingers. Margins with regard to critical heat flux (CHF), surface temperature and interface temperature between CFC and copper are studied. The fingers are now in fabrication. Before launching the manufacture, scale-one elements were fatigue tested and industrialisation processes were optimised in order to increase the manufacturing efficiency. As non-destructive controls are used all along the manufacturing process, a good reliability of the components is expected. Specific high temperature helium leak testing and infrared testing are used as a global acceptance test of each element. Up to now 100 fingers have been delivered.