Nuclear aspects of diagnostics in RTO/RC ITER

ITER (international thermonuclear experimental reactor) will be the first f usion device where the design of the plasma diagnostic systems will make ex tensive use of the materials and techniques developed in the nuclear techno logy held. The designs have to satisfy stringent requirements for tritium c onfinement, nuclear shielding and vacuum integrity. This paper introduces t he requirements for diagnostics in the ITER long pulse, burning plasma envi ronment, and addresses the impact of the reactor environment on the diagnos tics and ancillary equipment. These systems necessarily require access to t he plasma or first wall, which generally conflicts with the requirements of the basic machine. Holes are required through the first wall, primary shie lding, containment boundaries and biological shielding. Components have a l imited life and require maintenance. This paper describes the effect of the radiation environment on diagnostic design at different locations. Ex-vess el and in-vessel remote handling, hot cell refurbishment and tritium confin ement are also described. (C) 2000 Elsevier Science B.V. All rights reserve d.