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Title: Trapping state of hydrogen isotopes in carbon and graphite investigated by thermal desorption spectrometry

Thermal desorption spectrometry (TDS) has been investigated to obtain fundamental information of tritium behavior in graphite and carbon materials especially at high temperatures. 29 brands of graphite, HOPG, glassy carbon and CFC materials charged with deuterium gas are tested up to the temperature of 1735 K with a heating rate of 0.1 K/s. TDS spectra have five peaks at 600-700 K, around 900 K, 1200 K, 1300-1450 K and 1600-1650 K. The amounts of released deuterium have been compared with crystallographic parameters derived from XRD analysis. The results can be summarized as follows. First, TDS spectra of deuterium were quite varied among the samples tested, such as existence of peaks, peak temperatures and release amounts of deuterium. Secondly, TDS spectra may consist of five peaks, which are peak 1 (600-700 K), peak 2 (around 900 K), peak 3 (around 1200 K), peak 4 (1300-1450 K) and peak 5 (1600-1650 K). Thirdly, the correlations between the estimated surface area of edge surface and the total amount of released deuterium could be observed for peaks 4 and 5. Fourthly, high energy trapping site (peak 5) may exist even at edge surface or a near surface region, not only for intercalary. And fifth,more » in order to obtain the lower tritium retention for graphite and CFC materials, the material should be composed of a filler grain with a smaller crystallite size or having the smaller net edge surface in its structure. It is shown that heat treatment does not reduce originally existing trapping sites but trapping sites generated by neutron irradiation for instance can be reduced in some degree.« less
Authors:
 [1] ;  [2] ;  [3]
  1. Department of Electric and Electronic Engineering, Kinki University, Higashiosaka (Japan)
  2. Interdisciplinary Graduat School of Engineering Sciences, Kyushu University, Fukuoka (Japan)
  3. Institute for Materials Research, Tohoku University, Sendai (Japan)
Publication Date:
OSTI Identifier:
22429689
Resource Type:
Journal Article
Resource Relation:
Journal Name: Fusion Science and Technology; Journal Volume: 67; Journal Issue: 2; Conference: TRITIUM 2013: 10. International Conference on Tritium Science and Technology, Nice Acropolis (France), 21-25 Oct 2013; Other Information: Country of input: France; 13 refs.
Country of Publication:
United States
Language:
English
Subject:
70 PLASMA PHYSICS AND FUSION TECHNOLOGY; 75 CONDENSED MATTER PHYSICS, SUPERCONDUCTIVITY AND SUPERFLUIDITY; CHLOROFLUOROCARBONS; DESORPTION; DEUTERIUM; GRAPHITE; HEAT TREATMENTS; HEATING RATE; NEUTRONS; SPECTROSCOPY; TEMPERATURE RANGE 0400-1000 K; TEMPERATURE RANGE 1000-4000 K; TRAPPING; TRITIUM; X-RAY DIFFRACTION