Absorption and desorption of hydrogen, deuterium, and tritium for Zr--V--Fe getter

Journal Article · Sun Jul 01 00:00:00 EDT 1984 · J. Vac. Sci. Technol., A; (United States)

DOI:https://doi.org/10.1116/1.572406· OSTI ID:6436778

Ichimura, K; Inoue, N; Watanabe, K; Takeuchi, T

Nonevaporable getters have wide applicability for developing the tritium handling techniques for thermonuclear fusion devices. From this viewpoint, mechanisms of the absorption and desorption of hydrogen isotopes and the isotope effects were investigated for a Zr--V--Fe alloy (St-707) by means of the mass analyzed thermal desorption spectroscopy. It was observed that the absorption rate was proportional to the first power of the pressure, indicating that the rate limiting step is the dissociative adsorption of hydrogen isotopes on the surface. The activation energy was very small, in the order of magnitude of a few tens of calories per mole in a temperature range from -196 to 200 /sup 0/C. The desorption rate was proportional to the square of the amount of absorption, indicating that the rate limiting step is the associative desorption reaction of hydrogen atoms or ions diffused to the surface from the bulk. The rate constants for hydrogen and deuterium were determined as k/sub d/(H/sub 2/) = (5.3/sup +2.6//sub -1.7/)exp(-(28.0 +- 0.7) x 10/sup 3//RT) and k/sub d/(D/sub 2/) = (5.0/sup +2.7//sub -1.7/)exp(-(28.6 +- 0.8) x 10/sup 3//RT) in (1/Pa 1 s), respectively, where R is in (cal/mol deg). With regard to tritium, the rate constant was evaluated as k/sub d/(T/sub 2/) = (5.0/sup +20//sub -4.0/)exp(-(29.3 +- 3) x 10/sup 3//RT), however, the frequency factor will have to be corrected by knowing the relative sensitivity factor of the mass spectrometer for tritium (T/sub 2/).

• Research Organization: Tritium Research Center, Toyama University, 3190 Gofuku, Toyama 930, Japan
• OSTI ID: 6436778
• Journal Information: J. Vac. Sci. Technol., A; (United States), Vol. 2:3
• Country of Publication: United States
• Language: English

Related Subjects

70 PLASMA PHYSICS AND FUSION TECHNOLOGY
36 MATERIALS SCIENCE
DEUTERIUM
ADSORPTION
DESORPTION
GETTERS
SORPTIVE PROPERTIES
HYDROGEN
IRON ALLOYS
TRITIUM
VANADIUM ALLOYS
ZIRCONIUM ALLOYS
ACTIVATION ENERGY
KINETICS
MASS SPECTROSCOPY
ALLOYS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
ELEMENTS
ENERGY
HYDROGEN ISOTOPES
ISOTOPES
LIGHT NUCLEI
NONMETALS
NUCLEI
ODD-EVEN NUCLEI
ODD-ODD NUCLEI
RADIOISOTOPES
SORPTION
SPECTROSCOPY
STABLE ISOTOPES
SURFACE PROPERTIES
YEARS LIVING RADIOISOTOPES
700209* - Fusion Power Plant Technology- Component Development & Materials Testing
360104 - Metals & Alloys- Physical Properties