Investigation of fluid flow through ITER relevant leak geometries and relevance to ITER leak localization

► Simple model of water and helium flow through ITER relevant leak geometries is proposed. ► Validation of ITER concept of leak localization based on flow water flow restrictors presented. ► Viable concept scheme for ITER blanket leak localization proposed. Operational leaks into the main vacuum vessel from actively cooled in vessel components are expected to account for a significant loss of operational availability if timely localization and repair of the leak cannot be performed. Due to the complexity of the machine, and the progression to an active environment, traditional methods of leak localization may not be applicable to ITER. In order to place boundary constraints on the design of leak localization systems the conditions at the leak exit, and fluid expansion into the vacuum vessel, must be characterized. In turn, to understand the fluid conditions at the leak exit the mechanism of fluid flow through the leak must be understood. Simulations have been performed to study the flows of fluids (water and helium) through ITER relevant leak geometries. The simulations are supported by an experimental program described herein. The simulations, results and comparison with empirical data are presented in this paper. Application of the results to the design of leak localization systems is given and details of a proposed leak localization method based on the real time modification of a leak flow characteristics is presented.