A cryocondensation pump for the DIII-D Advanced Divertor Program

Conference · Sun Mar 01 04:00:00 EST 1992

OSTI ID:5476355

Smith, J P; Baxi, C; Reis, E; Sevier, L

A cryocondensation pump was designed for the baffle chamber of General Atomics DIII-D tokamak and will be installed in the fall of 1992. The purpose of the pump is to study plasma density control by pumping the divertor. The pump is toroidally continuous, approximately 10 m long and located in the lower outer corner of the vacuum chamber of the machine. It consists of a 1 m{sup 2} liquid helium-cooled surface surrounded by a liquid nitrogen-cooled shield to limit the heat load on the helium-cooled surface. The liquid nitrogen-cooled surface is surrounded by a radiation/particle shield to prevent energetic particles from impacting and releasing condensed water molecules. A thermal enhancement coating was applied to the nitrogen shell to lower the maximum temperature of the shell. The coating is non-continuous to keep the toroidal electrical resistance high. The whole pump is supported off the water-cooled vacuum vessel wall. Supports for the pump were designed to accommodate the thermal differences between the 4 K helium surface, the 77 K nitrogen shells, and the 300 K vacuum vessel supporting the pump and to provide a low heat leak structural support. Disruption loading on the pump was analyzed and a finite element structural analysis of the pump was completed. A testing program was completed to evaluate coating techniques to enhance heat transfer and emissivity of the various surfaces. Fabrication tests were performed to determine the best method of attaching the liquid nitrogen flow tubes to their shield surfaces and to determine the best alternative to fabricating the different shells of the pump. A prototype sector of the pump was built to verify fabrication and assembly techniques.

• Research Organization: General Atomics, San Diego, CA (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: AC03-89ER51114
• OSTI ID: 5476355
• Report Number(s): GA-A-20851; CONF-920607--8; ON: DE92011490
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700420* -- Fusion Technology-- Plasma-Facing Components-- (1992-)
CLOSED PLASMA DEVICES
CRYOPUMPS
DESIGN
DIVERTORS
DOUBLET-3 DEVICE
EQUIPMENT
FABRICATION
LABORATORY EQUIPMENT
PLASMA DENSITY
PUMPS
SHIELDING
TESTING
THERMONUCLEAR DEVICES
TOKAMAK DEVICES
VACUUM PUMPS