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Title: A cryocondensation pump for the DIII-D Advanced Divertor Program

Abstract

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 analysismore » 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.« less

Authors:
; ; ;
Publication Date:
Research Org.:
General Atomics, San Diego, CA (United States)
Sponsoring Org.:
USDOE, Washington, DC (United States)
OSTI Identifier:
10136446
Report Number(s):
GA-A-20851; CONF-920607-8
ON: DE92011490
DOE Contract Number:  
AC03-89ER51114
Resource Type:
Conference
Resource Relation:
Conference: 10. topical meeting on technology of fusion energy,Boston, MA (United States),7-12 Jun 1992; Other Information: PBD: Mar 1992
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; DOUBLET-3 DEVICE; CRYOPUMPS; DESIGN; DIVERTORS; PLASMA DENSITY; SHIELDING; TESTING; FABRICATION; 700420; PLASMA-FACING COMPONENTS

Citation Formats

Smith, J P, Baxi, C, Reis, E, and Sevier, L. A cryocondensation pump for the DIII-D Advanced Divertor Program. United States: N. p., 1992. Web.
Smith, J P, Baxi, C, Reis, E, & Sevier, L. A cryocondensation pump for the DIII-D Advanced Divertor Program. United States.
Smith, J P, Baxi, C, Reis, E, and Sevier, L. 1992. "A cryocondensation pump for the DIII-D Advanced Divertor Program". United States. https://www.osti.gov/servlets/purl/10136446.
@article{osti_10136446,
title = {A cryocondensation pump for the DIII-D Advanced Divertor Program},
author = {Smith, J P and Baxi, C and Reis, E and Sevier, L},
abstractNote = {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.},
doi = {},
url = {https://www.osti.gov/biblio/10136446}, journal = {},
number = ,
volume = ,
place = {United States},
year = {1992},
month = {3}
}

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