Hydrogen isotope exchange and conditioning in graphite limiters used in the Tokamak Fusion Test Reactor
Isotopic exchange experiments performed in the Tokamak Fusion Test Reactor (TFTR) are used to examine the outgassing and diffusive properties of graphite used as the plasma limiter. Changeover from hydrogen to deuterium for different periods ranges from approx.600 to 60 plasma discharges, which appears to be correlated in the limiter temperature. We present a simple analytical model that predicts a fast transient (approx.10 plasma discharges) changeover, where the deuterium fueling dilutes the adsorbed and near surface hydrogen, and a slowly changing term where bulk hydrogen diffuses to the surface. Using this model we can extract an activation energy for diffusion of 0.15 +- 0.02 eV. We hypothesize that interpore diffusion for this porous (approx.15%) material is consistent with our observations.
- Research Organization:
- Plasma Physics Laboratory, Princeton University, Princeton, New Jersey 08544
- DOE Contract Number:
- AC02-76CH03073
- OSTI ID:
- 5607470
- Journal Information:
- J. Vac. Sci. Technol., A; (United States), Vol. 4:3
- Country of Publication:
- United States
- Language:
- English
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Hydrogen isotope trapping on graphite collectors during an isotope exchange experiment in the Tokamak Fusion Test Reactor
Hydrogen isotope trapping on graphite collectors during an isotope exchange experiment in the Tokamak Fusion Test Reactor
Related Subjects
GRAPHITE
ATOM TRANSPORT
DEGASSING
SURFACE TREATMENTS
HYDROGEN
ADSORPTION
DIFFUSION
ISOTOPIC EXCHANGE
LIMITERS
TFTR TOKAMAK
DEUTERIUM
IMPURITIES
CARBON
ELEMENTAL MINERALS
ELEMENTS
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
MINERALS
NEUTRAL-PARTICLE TRANSPORT
NONMETALS
NUCLEI
ODD-ODD NUCLEI
RADIATION TRANSPORT
SORPTION
STABLE ISOTOPES
THERMONUCLEAR REACTORS
TOKAMAK TYPE REACTORS
700209* - Fusion Power Plant Technology- Component Development & Materials Testing