Reaction–diffusion simulations of hydrogen isotope trapping and release from cavities in tungsten, II: Array of cavities

Zibrov, M.; Schmid, K.

doi:10.1016/j.nme.2022.101219

Cited by 3 publications

(1 citation statement)

References 40 publications

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“…At most, the derived vacancy densities of about 0.4 at% can be used as an upper limit for first tritium loss calculations, as was done in [11]. However, this approach implies that vacancy-type defects dominate hydrogen isotope retention and that no macroscopic voids evolve at elevated temperatures that could retain tritium even in molecular form [97,98]. To address this issue, the same methodology is currently being applied to damaging at elevated temperature.…”

Section: Comparison With Literature Data and Discussionmentioning

confidence: 99%

A critical review of experiments on deuterium retention in displacement-damaged tungsten as function of damaging dose

Schwarz-Selinger

2023

Mater. Res. Express

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Experimental results from the literature on the evolution of deuterium retention in displacement-damaged tungsten as a function of damaging dose are presented. Except for a few outliers, retention is generally found to increase with the presence of displacement damage. However, total retention results scatter by three orders of magnitude for similar exposure temperatures and are difficult to compare, because they depend on experiment-specific parameters such as the irradiation energy used to produce the displacement damage or the deuterium exposure parameters such as fluence. Even local deuterium concentration measurements were found to scatter by more than one order of magnitude. An experimental methodology is proposed that allows robust conclusions about the evolution of deuterium retention with damage dose and the results are discussed in detail. Recrystallized tungsten is irradiated with 20.3 MeV self-ions at room temperature with different damage doses ranging from 0.001 to 2.3 displacements per atom. The defects are then decorated with a low flux, low-energy deuterium plasma at 450 K sample temperature. 3He Nuclear Reaction Analysis (NRA) shows that the deuterium concentration levels off from the linear increase already at very low damage dose of about 0.005 dpa. At a damage dose of 0.23 dpa a maximum deuterium concentration of about 1.4 at% is reached. Thermal Desorption Spectroscopy (TDS) shows that with damage increasing above 0.005 dpa, the overall shape of the desorption spectra does not change substantially, only their intensities increase. Total amounts derived from TDS are in quantitative agreement with results from 3He-NRA. Experimental results following this methodology also agree quantitatively with very recent parameter-free modeling of damage evolution.

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Section: Comparison With Literature Data and Discussionmentioning

confidence: 99%

A critical review of experiments on deuterium retention in displacement-damaged tungsten as function of damaging dose

Schwarz-Selinger

2023

Mater. Res. Express

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Surface-limited deuterium uptake of Ru films under plasma exposure

Wang

Zoethout

Kampen

et al. 2022

Journal of Applied Physics

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Blister formation has been an emerging research topic for extreme ultraviolet (EUV) mirrors exposed to hydrogen plasmas. Similar to plasma-facing materials in nuclear fusion reactors, it has been reported that blister formation in EUV mirrors is initiated by hydrogen uptake due to hydrogen ion or atom bombardment. However, the research so far has focused on Mo/Si multilayers exposed to only hydrogen ions or atoms, while the EUV mirror typically has a Ru capping layer facing hydrogen plasmas. We present experimental work to measure plasma-induced hydrogen uptake of Ru films. We bombarded our designed Ru-capped target with a low-temperature deuterium plasma and measured the deuterium retention using elastic recoil detection. Contrary to ion-driven deuterium uptake, the deuterium uptake rate of the Ru film had no dependence on the deuterium ion flux or energy after a period of plasma exposure. A reaction–diffusion model has been built to calculate the time evolution of deuterium retention, which well fits the experimental data. Based on this model, we conclude that the surface composition of the Ru film is the limiting factor for the deuterium uptake, which is seriously weakened when the surface is covered by Ru oxide. After the Ru oxide is reduced by the plasma, the uptake rate is predominantly driven by the deuterium surface coverage on metallic Ru. Our model also indicates that at the deuterium-populated Ru surface, deuterium has a low absorption barrier to penetrate the surface, which is supported by previously reported computational work.

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Cluster dynamics modeling of hydrogen retention and desorption in tungsten with saturation and multi-trapping effect of sinks

Chen,

Zhang,

Wei

et al. 2024

Nucl. Fusion

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Hydrogen (H) retention and desorption in tungsten (W)-based plasma-facing materials (PFMs) are still not well understood, largely due to the limitations of ex-situ observations in experimental detection methods like thermal desorption spectroscopy (TDS). In order to reveal the fundamental mechanisms behind H retention and desorption, we developed a cluster dynamics (CD) model, IRadMat-TDS, for theoretical modeling of depth distribution and TDS of deuterium (D) in polycrystalline W. The model newly includes the saturated absorption and emission of D in inherent sinks like grain boundaries (GBs), as well as the multi-trapping effect of D in various types of GBs with different trapping energies. The simulated TDS spectra are in agreement with experimental ones. For polycrystalline W under D ion irradiation within keV-energy range, two typical thermal desorption peaks in TDS at around 490 and 550 K are explicitly attributed to D emission from GBs and vacancies, respectively. And GBs play a major role in D retention. Moreover, the broad peaks in TDS come from the convolution of multi-trapping of D in sinks with different types of trapping sites rather than a single-site approximation.

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Reaction–diffusion simulations of hydrogen isotope trapping and release from cavities in tungsten, II: Array of cavities

Cited by 3 publications

References 40 publications

A critical review of experiments on deuterium retention in displacement-damaged tungsten as function of damaging dose

A critical review of experiments on deuterium retention in displacement-damaged tungsten as function of damaging dose

Surface-limited deuterium uptake of Ru films under plasma exposure

Cluster dynamics modeling of hydrogen retention and desorption in tungsten with saturation and multi-trapping effect of sinks

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