Fixed illumination system

A series of eight fixed-illumination (FI) probes are proposed for to replace the presently used, manually inserted and operated illumination probes for the Tokamak Fusion Test Reactor (TFTR). Illumination probes are used in the inspection of the vacuum-vessel internal components and allow photographs to be made for permanent records. Inspection can be made either remotely with the plasma TV diagnostic system, or locally by visual observation through unobstructed vacuum windows. The present system (three probes) is labor intensive, time consuming, requires the presence of personnel in the test cell, possesses no interlocks, and is not compatible with the D-T radiation-shielding configuration. The proposed probes will be staggered around the top and bottom of the vacuum vessel, permanently mounted in 10-in circular ports in the vessel´s interior. Four lamps are mounted on a flat inconel plate and a cylindrically shaped pivoting shutter is used to protect the lamps from deposits during plasma operation. The shutter functions as a thermal radiation shield for the port during probe operation and is operated by a pneumatic linear actuator which has a stroke of 4 in. Motion is transferred from the actuator to the shutter by a stainless steel cable. Current is supplied to the lamps with vacuum feedthroughs. The probe is interlocked, preventing its use during machine operation. A prototype probe has been fabricated and is undergoing testing