Divertor Materials Evaluation System (DiMES)
- General Atomics, San Diego, CA (United States)
- Univ. of California, San Diego, CA (United States)
- Sandia National Labs., Livermore, CA (United States)
- Argonne National Lab., IL (United States)
- Sandia National Labs., Albuquerque, NM (United States)
The mission of the Divertor Materials Evaluation System (DiMES) in DIII-D is to establish an integrated data base from measurements in the divertor of a tokamak in order to address some of the ITER and fusion power reactor plasma material interaction issues. Carbon and metal coatings of Be, W, V, and Mo were exposed to the steady-state outer strike point on DIII-D for 4-18 s. These short exposure times ensure controlled exposure conditions, and the extensive arrays of DIII-D divertor diagnostics provide a well-characterized plasma for modeling efforts. Postexposure analysis provides a direct measure of surface material erosion rates and the amount of retained deuterium. For carbon, these results match closely with the results of accumulated carbon deposition and erosion, and the corresponding deuterium retention of long term exposure tiles in DIII-D. Deuterium retention of different materials was measured using the {sup 3}He(d,p) {sup 4}He nuclear reaction. For carbon, these measurements showed peak deuterium areal density of about 8 {times} 10 {sup 18} D/cm{sup 2} in a co-deposited layer about 6 {micro}m deep, mainly at the usually detached inboard divertor leg. That layer of carbon near the inner divertor strike point has an atomic saturation concentration of D/C {approx} 0.25, which is not significantly lower than the laboratory-measured saturation retention of 0.4. Under the carbon contaminated background plasma of DIII-D, metal coatings of Be, V, Mo, and W were exposed to the steady state outer strike point under ELMing and ELM-free H-mode discharges. The rate of material erosion and tritium retention were measured. As expected, W shows the lowest erosion rate at 0.1 nm/s and the lowest deuterium uptake.
- Research Organization:
- General Atomics, San Diego, CA (United States); Sandia National Labs., Albuquerque, NM (United States); Argonne National Lab., IL (United States); Univ. of California, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE Office of Energy Research, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER52153; AC04-94AL85000; W-31109-ENG-38; FG03-95ER54294
- OSTI ID:
- 642774
- Report Number(s):
- GA--A22743; CONF-971090--; ON: DE98002634
- Country of Publication:
- United States
- Language:
- English
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