Analysis of an in-service rupture of the inner first wall of tore supra

The last experimental campaign of Tore Supra was also the last one with a set of plasma facing components mainly dating from the assembly of the machine in 1988. This campaign was interrupted a few days ahead of schedule because of the rupture of one coolant tube of the Inner First Wall (IFW). The rupture was observed by an abrupt increase of the pressure in the vessel. It was caused by a water leak which occurred 2 s after the end of the lower hybrid heating pulse during the current ramp-down. Investigations show that the accident is not related to the operation of the machine or a weaker element but rather to a localised heat flux exceeding the heat removal capability of the IFW.