Analysis of the consequences of targets feeding pipe rupture in Wendelstein 7-X experimental nuclear fusion device

摘要

Wendelstein nuclear fusion device W7-X is a stellarator type experimental device, developed by Max Planck Institute for Plasma Physics. Rupture of one of the 40 mm inner diameter coolant pipes providing water for the divertor targets during the “baking” operation mode is considered to be the most severe accident in terms of the plasma vessel pressurization. “Baking” is non-plasma operation mode during which the plasma vessel structures are heated and cleaned to the level required for plasma ignition. This paper presents the model of W7-X divertors, main cooling and “baking” circuits developed using thermalhydraulic state-of-theart code RELAP5 Mod3.3, and model of the plasma vessel, developed using the lumpedparameter code COCOSYS. In this paper the performed analysis (guillotine break of 40 mm diameter feeder pipe, connecting single upper horizontal target module) is presented. The results of simulation, performed using both models, allowed to investigate the processes in “baking” circuit and to evaluate the increase of pressure in plasma vessel.