NSTX High Temperature Sensor Systems
H.W. Kugel, B. McCormack, R. Kaita, P. Goranson, L. Guttadora, R. Hatcher, T. Holoman, D. Johnson, B. Nelson, C. Neumeyer, and A.L. Roquemore
Date of PPPL Report: November 1999
Presented at: The 18th IEEE/NPSS (Institute for Electrical and Electronics Engineers/Nuclear and Plasma Science Society) Symposium on Fusion Engineering (SOFE) which was held in Albuquerque, NM,on October 25-29, 1999.
The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 °C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 °C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 °C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed.