Rami analysis of the ITER cryoplant and cryodistribution systems

Abstract

The ITER cryogenic system is now entering the procurement phase in the framework of a large international collaboration. It will start operation with the first cool-down of the whole machine at Cadarache in southern France in 2019. A large cryoplant and cryodistribution system will allow the production of an equivalent refrigeration capacity of 65 kW at 4.5 K and 1300 kW at 80 K to superconducting magnets, cryostat thermal shields, cryopumps and pellet injection system. According to the project requirement document, ITER is designed to reach an overall inherent availability of 60 %. In order to reach this requirement, a specific reliability, availability, maintainability and inspectability (RAMI) analysis was performed. The risks related to the failure modes of the cryogenic subsystems were assessed, their contributions to ITER machine unavailability estimated and the necessary recommendations in terms of Design, Testing, Maintenance and Operation issued. Considering both inactive (hydrogen, deuterium) and active (deuterium-tritium) phases as defined by the ITER scientific program, this paper will present the RAMI results and mitigation actions applied. © 2012 American Institute of Physics.