Divertor materials evaluation system at DIII-D

Abstract

The divertor material evaluation system (DIMES) at DIII-D is a collaborative program between General Atomics, Sandia National Laboratories (SNL), and Argonne National Laboratory (ANL). This program was initiated in response to the need for understanding the interaction between the plasma and divertor surface materials in tokamaks. Material erosion, tritium retention, disruption effects and material transport are very important topics for the design of ITER. The first phase of the DIMES study is integral material exposure measurements. The second phase of the study is the installation of the DIMES sample changer mechanism. The mechanical design goal for the second phase is to allow the insertion of test materials and instrumented samples into the bottom divertor plate region of DIII-D without venting the tokamak. Various samples can then be exchanged overnight after exposures as short as one plasma shot. This paper presents the results of the integral experiments, the design of the DIMES sample changer mechanism and the planning of material evaluation experiments at DIII-D using the DIMES mechanism.