Analysis of an in-service rupture of the Inner First Wall of Tore Supra

TL;DR

This paper analyzes the rupture of the Inner First Wall of Tore Supra, caused by localized heat flux exceeding cooling capacity, leading to an abrupt coolant tube failure during plasma operation.

Contribution

It provides a detailed investigation into the specific cause of the rupture, highlighting the role of heat flux and component aging in plasma-facing components.

Findings

Rupture caused by localized heat flux exceeding cooling capacity

Failure occurred during plasma current ramp-down

Component aging contributed to vulnerability

Abstract

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 two seconds 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.