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Title: Hydrogen Isotope Investigations in Metals.

Abstract

Abstract not provided.

Authors:
;
Publication Date:
Research Org.:
Sandia National Lab. (SNL-CA), Livermore, CA (United States)
Sponsoring Org.:
USDOE National Nuclear Security Administration (NNSA)
OSTI Identifier:
1373171
Report Number(s):
SAND2016-7138PE
646051
DOE Contract Number:
AC04-94AL85000
Resource Type:
Conference
Resource Relation:
Conference: Proposed for presentation at the Intern Symposium held July 27, 2016 in Livermore, CA.
Country of Publication:
United States
Language:
English

Citation Formats

Chao, Paul, and Rick Karnesky. Hydrogen Isotope Investigations in Metals.. United States: N. p., 2016. Web.
Chao, Paul, & Rick Karnesky. Hydrogen Isotope Investigations in Metals.. United States.
Chao, Paul, and Rick Karnesky. Fri . "Hydrogen Isotope Investigations in Metals.". United States. doi:. https://www.osti.gov/servlets/purl/1373171.
@article{osti_1373171,
title = {Hydrogen Isotope Investigations in Metals.},
author = {Chao, Paul and Rick Karnesky},
abstractNote = {Abstract not provided.},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = {Fri Jul 01 00:00:00 EDT 2016},
month = {Fri Jul 01 00:00:00 EDT 2016}
}

Conference:
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  • A technique is reviewed which has the capability of investigating the interaction of hydrogen with metals on an atomic scale so that the initial phases of hydrogen interaction may be studied directly. Known as Imaging Atom-Probe Spectroscopy (IAPS) this technique combines the ability of the low-temperature Field-Ion Microscope (FIM) to image a metal surface in atomic resolution, and the single atom detection capability of a time-of-flight mass spectrometer to detect all surface species, including hydrogen.
  • The recycling of hydrogen isotopes (H, D and T) from the first wall material in a fusion device, as well as its tritium inventory and permeation characteristics will depend to a great deal on the surface properties of the material under consideration. Historically, the surface of the first wall was initially composed of such metals as stainless steel and nickel (Ni, the main constituent of Inconel) because of their good outgassing properties as vacuum vessel components. Then graphite and beryllium (Be) were favored due to their low Z properties. Presently, high Z refractory metals, molybdenum (Mo) and tungsten (W), aremore » also being tested in the devices with the hope that control of the boundary plasma would reduce the incident energy low enough to prevent sputtering. Furthermore, vanadium (V) and its alloys are considered for DEMO reactors for their low activation. Or niobium (Nb) and tantalum (Ta) are potentially suitable for super-permeable membrane for separation and purification of hydrogen isotopes in the exhaust gas.« less
  • The separation performance of tritium by the thermal diffusion method with low inventory was simulated as an alternative method to the cryogenic distillation in Fusion Fuel Cycle. The separation performance of thermal diffusion method was evaluated by the ternary transport equations with isotope exchange reaction. In this paper, the results for HT {minus} H{sub 2} system, show the isotope exchange reaction, H{sub 2} + T{sub 2} = 2HT, plays and important role in the separation performance of tritium, even in a trace level of tritium.
  • Due to the large mass difference between the two isotopes, D/H ratios can be strongly affected by chemical processes. Thus, they can be sensitive monitors of fluid source, temperature, and fluid-rock interactions in geologic settings. The lack of confidence in fractionation factors has significantly hindered realization of the potential of D/H ratios in geochemical studies. The authors describe a new experimental method, relying on SIMS analysis, that allows the precise determination of mineral-water D/H fractionation factors, and the analytical considerations that are required to make both precise and accurate measurements. The development of this method is based on the factmore » that diffusion rates are markedly anisotropic in many hydrous minerals, varying by over five orders of magnitude depending on the crystallographic orientation. The diffusion rates can be determined by conducting controlled exchange experiments of fixed duration using isotopically labeled waters that are enriched (strongly) with D, and then measuring the depth profile by SIMS.« less
  • A rotatable collector probe was used to expose several graphite samples to a deuterium-to-hydrogen-to-deuterium exchange experiment in the Tokamak Fusion Test Reactor (TFTR) at the start of the 1988 operations period. This experiment proved the utility of helium conditioning discharges in accelerating the changeover process. Samples included portions of a tile taken from the inner bumper limiter (POCO AXF-5Q graphite) of TFTR during the recent machine opening, and coupons which had been conditioned in the Plasma Interactive Surface Component Experimental Station (PISCES) by exposure to a helium plasma. The samples were exposed to different groups of the {approximately}100 1.4 MAmore » discharges that comprised the experiment. They were removed and analyzed for retained deuterium and impurities by nuclear reaction analysis and Rutherford backscattering spectrometry. Codeposited carbon layers had been formed with thicknesses up to several tenths of a micron. The inferred percentages of trapped hydrogenic species were in general agreement with spectroscopic data. The computed carbon fluence per D{sup +} discharge, 1.2 {times} 10{sup 17}C/cm{sup 2}, is compared to recent measurements on limiter tiles removed from TFTR. 22 refs., 3 figs., 1 tab.« less