D retention in Be exposed to fusion relevant mixed species D<mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" altimg="si1.gif" overflow="scroll"><mml:mrow><mml:msub><mml:mrow/><mml:mn>2</mml:mn></mml:msub><mml:mo>−</mml:mo></mml:mrow></mml:math>He plasma

Baldwin, M.J.; Schwarz-Selinger, T.; Doerner, R.

doi:10.1016/j.nme.2017.02.006

Cited by 11 publications

(8 citation statements)

References 22 publications

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“…The appearance of the sharp low-temperature D release peak for the Be-D layers deposited at 2.7 Pa and 8 Pa is in agreement with the observations by Baldwin et al [13]. Such a peak has also been observed in TDS spectra from bulk Be after keV D ion implantation above a critical fluence (around 10 21 Dm −2 ) [47][48][49][50], as well as after exposure to low-energy D ions from a plasma [51,52]. The presence of two closely located sharp peaks (like in the present study) or a sharp peak and a shoulder has also been observed in some studies with bulk Be [47][48][49][50][51].…”

Section: Discussionsupporting

confidence: 89%

Deuterium retention in mixed Be-W-D codeposited layers

et al. 2020

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Mixed beryllium-tungsten-deuterium (Be-W-D) layers (4.4-28.4 at.% W) were codeposited in a magnetron discharge in D 2 -Ar atmosphere at pressures of 0.8 Pa, 2.7 Pa, and 8 Pa and a substrate temperature of 373 ± 15 K. The composition of the layers was determined using nuclear reaction analysis and Rutherford backscattering spectrometry. D trapping states in the layers were examined using thermal desorption spectroscopy. At all pressures used, the D concentration in the layers has a nonmonotonic dependence on the W concentration, with the maximum occurring at 4.4-7.3% W. In this case, the D concentration is about two times greater than that in a Be-D layer; in W-D layers the D concentration is more than one order of magnitude smaller. Increase of pressure during deposition results in an increase of the D concentration in Be-D and Be-W-D (4.4-7.3% W) layers and is linked with the appearance of sharp low-temperature D release peaks near 450 K and 500 K. Increase of pressure also results in steeper decrease of the D concentration with increasing W concentration beyond 7.3%. It is concluded that for the layers deposited at 450 K and above, the effect of the presence of W (4.4-28.4%) on the D retention becomes small.

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Section: Discussionsupporting

confidence: 89%

Deuterium retention in mixed Be-W-D codeposited layers

et al. 2020

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“…This temperature is significantly higher than temperatures around 420 K (147 °C) associated with the hydrogen-isotope desorption peak from the external beryllium surface as observed both after deuterium implantation 34 or thermal loading with tritium 35 . Implantation experiments like the ones performed in the aforementioned publication, but also in other investigations 36 , 37 are often performed with BeO covered surfaces since beryllium oxidizes quickly in air. Experiments on atomic deuterium exposure of oxygen covered external beryllium surfaces by Lossev and Küppers 38 have revealed two major D 2 desorption peaks at 320 K and 450 K ascribed to the desorption from oxygen covered and clean beryllium surfaces, respectively.…”

Section: Resultsmentioning

confidence: 99%

Hydrogen and helium trapping in hcp beryllium

et al. 2023

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Even though hydrogen-metal surface interactions play an important role in energy technologies and metal corrosion, a thorough understanding of these interactions at the nanoscale remains elusive due to obstructive detection limits in instrumentation and the volatility of pure hydrogen. In the present paper we use analytical spectroscopy in TEM to show that hydrogen adsorbs directly at the (0001) surfaces of hexagonal helium bubbles within neutron irradiated beryllium. In addition to hydrogen, we also found Al, Si and Mg at the beryllium-bubble interfaces. The strong attraction of these elements to (0001) surfaces is underlined with ab-initio calculations. In situ TEM heating experiments reveal that hydrogen can desorb from the bubble walls at T ≥ 400 °C if the helium content is reduced by opening the bubbles. Based on our results we suggest the formation of a complex hydride consisting of up to five elements with a remarkably high decomposition temperature. These results therefore promise novel insights into metal-hydrogen interaction behavior and are invaluable for the safety of future fusion power plants.

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“…T D S N R A s c a l i n g l a w ( m e a n ) s c a l i n g l a w ( u n c e r t a i n t y ) The study by Baldwin et al [15] showed that the admixture of He in D plasma reduces D retention in bulk Be. A threefold reduction of D retention was measured in the case of exposure at 300 K and 10% of He in the plasma.…”

Section: Discussionmentioning

confidence: 99%

“…A low concentration of He (up to 6% of He in ITER [13]) will be present in the vessel as an ash from the D-T fusion reaction and moreover, ITER will operate with He/H plasma mixture during the Pre-Fusion Power Operation (PFPO) phase [14]. It has been shown that inclusion of He in D plasma reduces D retention in bulk Be exposed to D − He plasma mixture [15,16]. The aim of the current study is to investigate the influence of He on D retention in Be-D-He co-deposits.…”

Section: Introductionmentioning

confidence: 99%

The influence of helium on deuterium retention in beryllium co-deposits

Založnik¹,

Baldwin²,

Doerner³

et al. 2018

Journal of Nuclear Materials

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Tritium co-deposition with materials from the plasma-facing components is expected to be the main contributor to tritium retention in ITER. Since He will also be present in the plasma as fusion ash during the DT campaign, this study focuses on the effect of He on D retention in Be co-deposits. The PISCES-B linear plasma device was used to create co-deposited BeD He layers for various deposition temperatures (295 K-475 K) and He concentrations in D − αHe plasma mixtures (0 ≤ α ≤ 0.1). Thermal desorption spectroscopy and nuclear reaction analysis were used to determine the D concentration in co-deposits. For the lowest He concentration (1%) an increase of D retention was observed for the deposition at room temperature, whereas for higher He concentrations a declining trend of D retention was found. Including 10% of He in the plasma is found to reduce D retention at deposition temperatures below 425 K and have a negligible effect at higher deposition temperatures.

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D retention in Be exposed to fusion relevant mixed species D2−He plasma

Cited by 11 publications

References 22 publications

Deuterium retention in mixed Be-W-D codeposited layers

Deuterium retention in mixed Be-W-D codeposited layers

Hydrogen and helium trapping in hcp beryllium

The influence of helium on deuterium retention in beryllium co-deposits

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