ITER operational availability and fluence objectives

The ITER availability objective is to reach for the machine operation in H phase an inherent availability of 60% and an operational availability of 32% assuming three 8 h plasma shifts operating mode and typically 8-month major shutdown after each 16-month experimental campaign. A functional analysis of the overall ITER machine from highest level functions down to main operational functions has been developed. The inherent availability (A_I) objective of ITER has been defined on the basis of a bottom-up approach and using the results of reliability, availability maintainability and inspectability (RAMI) analyses. The ITER strategy in terms of operational availability (A_O), Plasma pulse availability (A_P) and fluence objectives is not only to improve reliability by optimizing the design but also to gain the maximum of operation time by decreasing the scheduled downtime for preventive maintenance and increasing the maintainability of the operational functions, thus decreasing the frequency and the time to maintain or/and to repair.