Management of a water leak on actively cooled fusion devices

Abstract ITER will be the most important machine equipped with actively cooled plasma facing components (PFCs). In case of abnormal events during a discharge, the PFC will be submitted to localized transient phenomena (high power densities, run away electrons, etc.), leading, in the worst case, to the degradation of the PFC wall and possibly to a water leak. In any case, a leak will have important consequences for the PFCs and equipment located in the vacuum vessel or connected to the ports such as seals, pumping systems or diagnostics. Considerable experience of these events has been gained at Tore Supra over a period of more than 10 years [J.J. Cordier, Ten years of maintenance on Tore Supra actively cooled components, in: Proceedings of the 21th Symp. of Fusion Technology (SOFT), Madrid, Spain, September, 2000.], which will be useful for the next step machines. This paper describes for each leak size type the procedures for maintaining save conditions in the vacuum vessel. It also presents the methods used at Tore Supra to drain-off the primary loop circuits and to identify the leaky PFC.