Nuclear technology aspects of ITER vessel-mounted diagnostics

ITER has diagnostics with machine protection, basic and advanced control, and physics roles. Several are distributed on the inner and outer periphery of the vacuum vessel. They have reduced maintainability compared to diagnostics in ports. They also endure some of the highest nuclear and EM loads of any diagnostic for the longest time. They include: - Inductive sensors for time-integrated and raw inductive measurements; - Steady-state magnetic sensors to correct drifts of the inductive sensors; - Bolometer cameras to provide electromagnetic radiation tomography; - Microfission chambers and neutron activation stations to provide fusion power and fluence; - MM-wave reflectometry to measure the plasma density profile and the plasma-wall distance and; - Wiring to service magnetics, bolometry, and in-vessel instrumentation. This paper summarises the key technological issues these diagnostics arising from the nuclear environment, recent progress and outstanding R&D for each system.