Speaker
Description
Tokamaks, as complex technical devices, need regular maintenances to insure optimal operational conditions. The major 2012-2016 shutdown, dedicated to the upgrade of Tore Supra, was the opportunity to engage important maintenance actions, preparing the restart and insuring the optimal sustainability of the future subsystems of the WEST tokamak. An overall maintenance plan, based on a risk analysis and the use of the criticality matrix inspirited by the ITER RAMI approach, was established.
Following this long shutdown, the WEST tokamak is now facing a new ten years operation period. The larger access for international partners requires reaching the adequate reliability and availability. Having a direct impact on the scientific program execution, but also representing more than half of the hardware financial effort of the overall operation budget, maintenance activities evolved in 2017, leading to an evolution of methods, tools and organization.
From the maintenance point of view, a tokamak is a common industrial device, where an availability level is targeted, not to meet financial or industrial objectives, but to support the experimental program requirements. Consequently, standard maintenance tools and methods can be adopted. Management of technical activities had been adapted to clearly distinguish operation, curative and preventive maintenances, and upgrade projects, all these activities being not driven by the same objectives and constraints. For each WEST technical subsystems, a maintenance plan review is annually organized, focusing on current engaged activities and on the forecast maintenance actions. Working through this annual plan, all the technical incidents, notably occurring during experimental sessions, are monitored.
The method used for such analysis leading to an optimized balance between curative and preventive maintenance, and the development of conditional maintenance using continuous monitoring will be described. The evolution of the criticality versus the resources engaged will be highlighted for each major subsystems of WEST.
