Design and analysis of the cryopump for the DIII-D advanced divertor
- General Atomics, San Diego, CA (United States)
- Oak Ridge National Lab., TN (United States)
A cryocondensation pump for the DIII-D advanced diverter program is to be installed in the vacuum vessel in the fall of 1992. The purpose of the cryopump is to remove gas from the diverter, reduce recycling to the plasma, and to provide reduced density plasmas for experimental study. The pump is designed for a pumping speed of 50,000 l/s at 0.4 mtorr. The major pump components are toroidally continuous to minimize inductive voltages, thereby greatly reducing the risk of any electrical breakdown during disruptions. The cryopump consists of a 25mm Inconel tube, 10m long, cooled by liquid helium. It is surrounded by liquid nitrogen-cooled shields and a segmented ambient temperature radiation/particle shield. The outer nitrogen shield has a toroidally discontinuous copper coating to enhance thermal conductivity while maintaining a high toroidal electrical resistance to minimize electromagnetic loads during disruptions. The pump is cooled by 10 g/s of liquid helium at an inlet pressure of 115 kPa and temperature of 4.35 K. The pump is subjected to a steady-state heat load of <10 W due to conduction and radiation heat transfer. The helium tube will be subjected to Joule heating of <182J due to induced current and a particle load of <20 W during plasma operation. Thermal analysis and tests show that the helium tube can absorb a transient heat load of up to 100 W for 10s and still pump deuterium at 6.3 K.
- Research Organization:
- General Atomics, San Diego, CA (United States)
- Sponsoring Organization:
- USDOE, Washington, DC (United States)
- DOE Contract Number:
- AC03-89ER51114
- OSTI ID:
- 10184606
- Report Number(s):
- GA-A-21016; CONF-920930-7; ON: DE93001357
- Resource Relation:
- Conference: 17. symposium on fusion technology (SOFT-17),Rome (Italy),14-18 Sep 1992; Other Information: PBD: Sep 1992
- Country of Publication:
- United States
- Language:
- English
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