TORE SUPRA first-wall description and behaviour during the initial plasma experiments

TORE SUPRA is a large-size, high-field superconducting tokamak (BΦ=4.5 T, R=2.37 m, a=0.8 m). It has been completed in the beginning of 1988 and is starting its experimental operation. The plasma-wall interaction programme will be mainly devoted to obtaining very long pulses in the next future, i.e. the control of impurity content, power and particule exhaust. The design of the first-wall items takes this into account. The inner wall is made of graphite tiles brazed on stainless steel tubes, the outer wall of stainless steel panels. Moreover, three graphite limiters and six ergodic divertor modules have already been installed. Each of these elements is water-cooled (Twater=150-2300C, p=3.6 MPa). Vessel pumping is achieved by means of three turbomolecular pumps providing 9000 l/s H2 pumping speed. A 2500C baking capability of the vessel is also available. First operations were mainly devoted to conditioning and carbonizing the whole plasma chamber, with RG discharges, allowing to work in homogeneous conditions. The first tokamak discharges are studied for a better knowledge of plasma control and stability in this configuration. Then, power deposition will be particularly investigated so as to prepare for the next steps: additional power and pump limiter operation. (orig.)