Helium leak detection in JET in the presence of high deuterium partial pressure
Leak detection in JET (--200 m/sup 3/ volume, --8000 m length of welds, --300 bolted vacuum connections, base pressure at room temperature 2 x 10/sup -9/ mbar) had originally been based on the use of helium (/sup 4/He) as a tracer gas. Later, high deuterium (D/sub 2/) partial pressures due to D/sub 2/ plasma operation made high-sensitivity leak testing by standard methods with /sup 4/He impossible; hence, alternative methods had to be developed. This eventually led to the use of a high-resolution Omegatron mass spectrometer able to separate D/sub 2/ and /sup 4/He. Additional compression and selective pumping provides a sensitivity of 10/sup -9/ mbar l s/sup -1/. The advantages of the Omegatron system compared with other alternative methods will be presented. The use of a fully tritium compatible Omegatron in conjunction with --400 tracer gas tubes during the active phase leak detection will be discussed.
- Research Organization:
- JET Joint Undertaking, Abingdon, OX14 3EA, United Kingdom
- OSTI ID:
- 6342625
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 5:4
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
JET TOKAMAK
LEAK DETECTORS
OPERATION
PERFORMANCE
DEUTERIUM
HELIUM
MASS SPECTROMETERS
MASS SPECTROSCOPY
SENSITIVITY
ELEMENTS
FLUIDS
GASES
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MEASURING INSTRUMENTS
NONMETALS
NUCLEI
ODD-ODD NUCLEI
RARE GASES
SPECTROMETERS
SPECTROSCOPY
STABLE ISOTOPES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing