DocumentCode :
3594197
Title :
Fabrication and installation of the DIII-D radiative divertor structures
Author :
Hollerbach, M.A. ; Smith, J.P.
Author_Institution :
Gen. Atomics, San Diego, CA, USA
Volume :
1
fYear :
1997
Firstpage :
377
Abstract :
Phase 1A of the Radiative Divertor Program (RDP) is now installed in the DIII-D tokamak located at General Atomics. This hardware was added to enhance both the Divertor and Advanced Tokamak research elements of the DIII-D program. This installation consists of a divertor baffle enveloping a cryocondensation pump at the upper outer divertor target of DIII-D. The divertor baffle consists of two toroidally continuous Inconel 625 water-cooled rings and a toroidal array of discontinuous radiatively-cooled plates. The water-cooled rings are each comprised of four quadrants, mechanically formed, chem.-milled, and resistance and TIG welded Inconel 625 panels. The supports attaching the panels to the vessel wall are designed to accommodate the differential thermal expansion between the rings and vessel during bake and to react the electromagnetic loads induced during disruptions. They are made from either Inconel 625 or Inconel 718 depending on the stress levels predicted in Finite Element Analysis. Gas seals are designed to limit the leakage from the baffle chamber back to the core plasma to 2,500 l/s and incorporate plasma sprayed alumina to minimize currents flowing through them. The bulk of the water-cooled ring fabrication was performed by a vendor, however, the final machining of penetrations in the conical ring for diagnostic access was performed in-house using a unique machining configuration. This configuration, and the machining of the diagnostic cutouts is described. Graphite tiles were machined from ATJ graphite to form a smooth plasma-facing surface. The installation of all divertor components required only four weeks. This divertor installation included electro-discharge welding studs, accurately locating the supports using a toroidally continuous tooling plate and local fixtures, and mounting the structures. Tooling was used during ex-vessel test assembly to greatly simplify the installation process. This process is reviewed
Keywords :
Tokamak devices; finite element analysis; fusion reactor design; DIII-D radiative divertor structures; DIII-D tokamak; Finite Element Analysis; Inconel 718; Radiative Divertor Program; TIG welded Inconel 625 panels; baffle chamber; bake; conical ring; core plasma; cryocondensation pump; diagnostic cutouts; discontinuous radiatively-cooled plates; disruptions; divertor baffle; electro-discharge welding studs; electromagnetic loads; ex-vessel test assembly; fabrication; gas seals; graphite tiles; installation; leakage; local fixtures; plasma sprayed alumina; smooth plasma-facing surface; thermal expansion; toroidally continuous Inconel 625 water-cooled rings; toroidally continuous tooling plate; upper outer divertor target; vessel wall; water-cooled ring fabrication; Atomic measurements; Fabrication; Hardware; Joining processes; Machining; Plasma diagnostics; Thermal expansion; Thermal spraying; Tokamaks; Welding;
fLanguage :
English
Publisher :
ieee
Conference_Titel :
Fusion Engineering, 1997. 17th IEEE/NPSS Symposium
Print_ISBN :
0-7803-4226-7
Type :
conf
DOI :
10.1109/FUSION.1997.687059
Filename :
687059
Link To Document :
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