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2 edition of Deuterium trapping in tungsten. found in the catalog.

Deuterium trapping in tungsten.

Michael Poon

Deuterium trapping in tungsten.

by Michael Poon

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  • 25 Currently reading

Published .
Written in English


About the Edition

Tungsten is one of the primary material candidates being investigated for use in the first-wall of a magnetic confinement fusion reactor. An ion accelerator was used to simulate the type of ion interaction that may occur at a plasma-facing material. Thermal desorption spectroscopy (TDS) was the primary tool used to analyze the effects of the irradiation. Secondary ion mass spectroscopy (SIMS) was used to determine the distribution of trapped D in the tungsten specimen. The tritium migration analysis program (TMAP) was used to simulate thermal desorption profiles from the D depth distributions. Fitting of the simulated thermal desorption profiles with the measured TDS results provided values of the D trap energies.Deuterium trapping in single crystal tungsten was studied as a function of the incident ion fluence, ion flux, irradiation temperature, irradiation history, and surface impurity levels during irradiation. The results show that deuterium was trapped at vacancies and voids. Two deuterium atoms could be trapped at a tungsten vacancy, with trapping energies of 1.4 eV and 1.2 eV for the first and second D atoms, respectively. In a tungsten void, D is trapped as atoms adsorbed on the inner walls of the void with a trap energy of 2.1 eV, or as D2 molecules inside the void with a trap energy of 1.2 eV.Deuterium trapping in polycrystalline tungsten was also studied as a function of the incident fluence, irradiation temperature, and irradiation history. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at 500 K. In general, D trapping is greater in polycrystalline tungsten than in single crystal tungsten. To simulate mixed materials comprising of carbon (C) and tungsten, tungsten specimens were pre-irradiated with carbon ions prior to D irradiation. Deuterium trapping could be characterized by three regimes: (i) enhanced D retention in a graphitic film formed by the C+ irradiation; (ii) decreased D retention in a modified tungsten-carbon layer; and (iii) D retention in pure tungsten.

The Physical Object
Pagination168 leaves.
Number of Pages168
ID Numbers
Open LibraryOL20339021M
ISBN 100612916669

  We show that tritium removal from tungsten can be enhanced by the isotope exchange mechanism by doing the baking in H atmosphere. The results show that the retained deuterium from 30 keV implantation can be expected to drop almost to zero after 24 h annealing at °C in H atmosphere. Annealing in vacuum requires temperatures above °C Cited by: 2. Deuterium Trapping in Tungsten by John Patrick Town Roszell Deuterium trapping in PCW and single crystal tungsten (SCW) was studied as a function of ion energy and substrate temperature. Deuterium retention was shown to decrease with Cited by: 2.

Tungsten carbide is exposed to deuterium plasmas in fusion reactors. In this context, studying of the interaction between deuterium and impurities originating from the plasma and tungsten carbide is of scientific interest. Molecular dynamics simulations of cumulative deuterium cobombardment with C, W, He, Ne, or Ar impurities on crystalline tungsten carbide were Cited by:   Transmission electron microscope is widely used to investigate the defects induced by heavy ion irradiation and deuterium plasma exposure in tungsten, however, results differ greatly between in situ and near-bulk irradiation experiments. Here we adopt the back-thinned electropolishing and re-electropolishing method to study the microstructure in the peak Author: Wangguo Guo, Shiwei Wang, Lin Ge, Engang Fu, Yue Yuan, Long Cheng, Guang-Hong Lu.

  Abstract. An investigation on mechanisms of hydrogen and deuterium trapping in tungsten during irradiation by hydrogen ion plasma with oxygen impurity using the methods of thermal desorption spectrometry (TDS) and secondary ion mass spectrometry (SIMS) is presented in this by: 1. v Masashi Shimada and Brad J. Merril Fusion Safety Program, Idaho National Laboratory Deuterium behavior in HFIR neutron- irradiated tungsten under US-Japan PHENIX program IAEA CRP 3rd Research Coordination Meeting on June, J


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Deuterium trapping in tungsten by Michael Poon Download PDF EPUB FB2

PAPER Deuterium trapping by deformation-induced defects in tungsten To cite this article: M. Zibrov et al Nucl. Fusion 59 View the article online for updates and by: 1. Deuterium trapping in polycrystalline tungsten also occurs primarily at vacancies and voids with the same trap energies as in single crystal tungsten; however, the presence of grain boundaries promotes the formation of large surface blisters with high fluence irradiations at K.

Most of the previous experimental studies on this subject employed annealing of as-received dislocation-rich W samples at various temperatures, which resulted in the decrease of dislocation density, and investigated its influence on deuterium (D) trapping [11–13].Cited by: 1.

Deuterium trapping by deformation-induced defects in tungsten Article   in   Nuclear Fusion 59(10)   August   with  91 Reads  How we measure 'reads'. Deuterium Trapping in Rolled Polycrystalline Tungsten Exposed to Low Energy Plasma Aleksandr RUSINOV, Mizuki SAKAMOTO1), Hideki ZUSHI2), Ryohei OHYAMA, Koichiro HONDA, Ikuji TAKAGI3), Tetsuo TANABE and Naoaki YOSHIDA2) Interdisciplinary Graduate School of Engineering Sciences, Kyushu University, KasugaJapan.

The deuterium trapping behaviors in tungsten damaged by light ions with lower energy (10 keV C + and 3 keV He +) or a heavy ion with higher energy ( MeV Fe 2+) were compared by means of TDS to understand the effects of cascade collisions on deuterium retention in by: To understand the deuterium trapping in damaged tungsten in more detail, it is important to measure the deuterium depth distributions.

The purpose of this work is to investigate the deuterium behavior such as retention and depth distributions in tungsten damaged by Cited by:   Deuterium permeation studies for polycrystalline tungsten foil have been conducted to provide data for estimating tritium transport and trapping in tungsten-clad divertors proposed for advanced fusion-reactor by: The vacancies trap deuterium atoms, and the long positron lifetime decreases, as per the tendencies observed in previous experiments and simulations [ 11, 12, 22 ].

The long positron lifetime did not change so significantly in the present study. Since positrons penetrate to depths of approximately µm, Cited by: 5.

Deuterium Retention and Trapping in Polycrystalline Tungsten under Simultaneous Implantation of Deuterium with Helium and with Neon Tamara Finlay (PCW) and recrystallized tungsten (RCW) irradiated with deuterium ions (D-only) or deuterium and Author: Tamara Jean Finlay.

The trapping of plasma-induced deuterium in tungsten single crystal pre-irradiated with high-energy ions of H, D and He and then annealed at K has been studied by thermal desorption. Deuterium trapping at defects created with neutron and ion irradiations in tungsten. The effects of neutron and ion irradiations on deuterium (D) retention in tungsten (W) were investigated.

tests for the specimens irradiated with 20 MeV W ions showed that the defects which play a dominant role in the trapping at high temperature were Cited by: For the W crystal pre-irradiated by He ions below 10 21 He / m 2, defect accumulation, trapping and thermal release behavior of D atoms were similar to those in a crystal implanted by 5 keV D ions without He pre-irradiation.

This suggests that trapping mechanism of D atoms is identical for both energetic D and He by:   The trapping and release of deuterium are investigated by means of re-emission and thermal desorption spectroscopy. The results have been compared with previous data from graphite and from tungsten prepared by various methods.

It is found that a few percent of carbon impurities strongly increases the deuterium inventory in by: The effect of ion damage on deuterium trapping in tungsten: Authors: Abstract A systematic study investigating the effect of ion-induced damage, due to prior ion implantation, on deuterium retention in tungsten has been performed.

Implantations with keV D 3 + ions. the type of pre-existing defects (deuterium trapping sites) and ob- tain the change in the PAL of vacancies by deuterium trapping. Thermal desorption spectra of deuterium were also obtained af- ter deuterium charging.

The trapping sites and peak temperatures of deuterium release from tungsten were identified from these re- sults. by: 5. Deuterium trapping at defects created with neutron and ion irradiations in tungsten Y.

Hatano1, M. Shimada2, T. Otsuka3, Y. Oya4, The effects of neutron and ion irradiations on deuterium (D) retention in tungsten (W) were trap occupancy by D sensitively depends on the concentration of D in the solid solution state. MODELING OF TRAPPING/DETRAPPING OF HYDROGEN ISOTOPES IN TUNGSTEN MATERIALS WHISCI modeling TEAM (CS Becquart, R Bisson, N Fernandez, Y Ferro, Predict and control Tritium/Deuterium trapping/degasing Coordinator: Regis Bisson (PIIM Laboratory) “Macroscopic rate equation modeling of trapping/detrapping of hydrogen isotopes in tungsten.

The trapping of plasma-induced deuterium in tungsten single crystal pre-irradiated with high-energy ions of H, D and He and then annealed at K. In combination of the reduction of S parameter in the non- and pre-annealed tungsten, it is implied that deuterium trapping ability of vacancy-type defects is constrained in the non-annealed tungsten.

And this confinement effect concentrates on the top surface and it becomes weaker with increasing by: 2. Molecular Dynamics Simulations of Deuterium Trapping and Re-emission in Tungsten Carbide† Katharina Vo¨rtler* and Kai Nordlund Association EURATOM-Tekes, Department of Physics, P.O.

FIN UniVersity of Helsinki, Finland ReceiVed: J ; ReVised Manuscript ReceiVed: January 5, Tungsten carbide is exposed to deuterium plasmas in fusion .The effects of neutron and ion irradiations on deuterium (D) retention in tungsten (W) were investigated. Specimens of pure W were irradiated with .Using specimens of polycrystalline tungsten (PCW) and recrystallized tungsten (RCW) irradiated with deuterium ions (D-only) or deuterium and helium ions simultaneously (SIM D-He) at K, the effects of W grain size on D retention in the presence of He was : Tamara Jean Finlay.