COLLECTION AND ANALYSIS OF PARTICULATE FROM THE DIII-D TOKAMAK

Particulate (i.e. Tokamak dust) has been collected from the III-D Toka mak located at General Atomics in San Diego, CA, USA. Two methods were used to collect particulate with the goal of preserving the particle size distribution and physical characteristics of the particulate. Vac uum collection on substrates and adhesion removal with metallurgical r eplicating tape were chosen as non-intrusive sampling methods. Samplin g was completed in four toroidal locations of the machine; the 0-90 de grees area, the 90-180 degrees area, the 180-270 degrees area, and the 270-360 degrees area. The 0 degrees direction designates the north si de of the DIII-D machine. Four tiles in each area were sampled; the fi rst vertical tile above the floor on the centerpost, a floor tile next to the center post, a tile on the isolated ring, and the first tile u p from the isolated ring on the divertor. In addition, samples were co llected from underneath the floor tiles at the 275 and the 75 degrees locations. The count median diameter of the samples ranged from 0.50 t o 0.86 mu m, with geometric standard deviations ranging from 2.0 to 3. 5. Diameters of average mass calculated from Hatch-Choate equations ba sed upon log normal distribution characteristics ranged from 2.8 to 7. 5 mu m. (C) 1998 Published by Elsevier Science S.A. All rights reserve d.