Field installed brazed thermocouple feedthroughs for high vacuum experiments

Conference · Thu Dec 01 04:00:00 EST 1983

OSTI ID:6730801

Anderson, P M; Messick, C

In order to reduce the occurrence of vacuum leaks and to increase the availability of the DIII vacuum vessel for experimental operation, effort was applied to developing a vacuum-tight brazed feedthrough system for sheathed thermocouples, stainless steel sheathed conductor cables and tubes for cooling fluids. This brazed technique is a replacement for elastomer O ring sealed feedthroughs that have proven vulnerable to leaks caused by thermal cycling, etc. To date, about 200 feedthroughs have been used. Up to 91 were grouped on a single conflat flange mounted in a bulkhead connector configuration which facilitates installation and removal. Investigation was required to select a suitable braze alloy, flux and installation procedure. Braze alloy selection was challenging since the alloy was required to have: (1) Melting temperature in excess of the 250/sup 0/C (482/sup 0/F) bakeout temperature. (2) No high vapor pressure elements. (3) Good wetting properties when used in air with acceptable flux. (4) Good wettability to 300 series stainless steel and Inconel.

• Research Organization: GA Technologies, Inc., San Diego, CA (USA)
• DOE Contract Number: AT03-76ET51011
• OSTI ID: 6730801
• Report Number(s): GA-A-17225; CONF-831203-165; ON: DE84013556
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
700209* -- Fusion Power Plant Technology-- Component Development & Materials Testing
BRAZING
CONTAINERS
DOUBLET REACTORS
ELECTRIC PROBES
FABRICATION
JOINING
LANGMUIR PROBE
MEASURING INSTRUMENTS
PRESSURE VESSELS
PROBES
THERMAL CYCLING
THERMOCOUPLES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
WELDING
WIRES