Helium-Hydrogen Synergistic Effects in Structural Materials Under Fusion Neutron Irradiation

Huang, Jia; Liu, Haochen; Gao, Zhiying; Su, Yue; Li, Qingyuan; Ge, Wei; Luo, Fengping; Xia, Songqin; Cao, Liuxuan; Xue, Jianming; Wang, Yugang; Wang, Chenxu

doi:10.3389/fmats.2022.849115

Cited by 11 publications

(3 citation statements)

References 63 publications

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“…Among these irradiation damage effects, one pivotal concern is the swelling of structural materials, which stems from the generated cavities, severely threatening the integrity of nuclear structural materials and the operational safety of nuclear reactors. Herein, the term cavity refers to a small volume consisting of vacancies and (or) hydrogen (H) and (or) helium (He) gas atoms as a generic term for void and bubble [5]. Cavity swelling rate has been utilized as one of the pivotal criteria for material designing and screening in the reactor design [6,7].…”

Section: Introductionmentioning

confidence: 99%

Dynamic investigations on hydrogen–helium interaction around the vacancy in BCC iron from ab-initio calculations

Luo

Huang²,

Li³

et al. 2023

Nucl. Fusion

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Coexistence of hydrogen (H) and helium (He) under vacancy (V) supersaturation in the fusion environment alters the dynamic evolution of cavities and ultimately influences the swelling of structural materials. Herein, we investigate H-He interaction around a vacancy as one prototype trapping site for H and He in body-centered cubic (BCC) iron (Fe) utilizing ab-initio calculations from the thermal dynamics. First, we demonstrate the significantly stronger He-V interaction than H-V interaction by comparing the dynamic trapping and de-trapping of H with those of He. Furthermore, we confirm the repulsive H-He interaction around the vacancy by examining their hopping around H-He-V complexes. The prior He in the vacancy imposes weak influence on the dynamic trapping of H, while enhances H de-trapping. Due to the prior He, more H atoms can be accommodated in the vacancy resulting from larger H-H distances to attenuate repulsive H-H interaction. The dynamic trapping of He by the vacancy is weakly influenced even though the vacancy is densely coated by the prior H. There exists a critical density of the prior H in the vacancy, below which the prior H enhances He de-trapping. Above this critical density, He de-trapping is inhibited by the prior H. This work provides significant dynamic insights at the atomic scale towards a better understanding of the cavity nucleation and H-isotopes/He retention in structural materials in the fusion environment.

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Section: Introductionmentioning

confidence: 99%

Dynamic investigations on hydrogen–helium interaction around the vacancy in BCC iron from ab-initio calculations

Luo

Huang²,

Li³

et al. 2023

Nucl. Fusion

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“…The high radiation tolerance of nanoscale multilayer Zr/Nb systems has been demonstrated in recent studies, including helium ion irradiation [ 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 ]. Helium atoms are produced in materials as a result of nuclear reactions (n, α) [ 26 ] and tend to accumulate in vacancies and interstitials with the formation of helium bubbles, leading to changes in the macroscopic properties of the irradiated material [ 27 , 28 , 29 , 30 , 31 , 32 , 33 ]. However, the accumulation of helium atoms at the Zr/Nb interface and their effect on the atomic and electronic structure of metals remain incompletely understood.…”

Section: Introductionmentioning

confidence: 99%

Features of Helium–Vacancy Complex Formation at the Zr/Nb Interface

Svyatkin

Laptev

2023

Materials

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A first-principles study of the atomic structure and electron density distribution at the Zr/Nb interface under the influence of helium impurities and helium–vacancy complexes was performed using the optimised Vanderbilt pseudopotential method. For the determination of the preferred positions of the helium atom, the vacancy and the helium–vacancy complex at the interface, the formation energy of the Zr-Nb-He system has been calculated. The preferred positions of the helium atoms are in the first two atomic layers of Zr at the interface, where helium–vacancy complexes form. This leads to a noticeable increase in the size of the reduced electron density areas induced by vacancies in the first Zr layers at the interface. The formation of the helium–vacancy complex reduces the size of the reduced electron density areas in the third Zr and Nb layers as well as in the Zr and Nb bulk. Vacancies in the first niobium layer near the interface attract the nearest zirconium atoms and partially replenish the electron density. This may indicate a possible self-healing of this type of defect.

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“…There is also a discrepancy regarding the specific effects of H and He on cavity behaviors, which may be related to differences in irradiation temperatures, material systems, damage rates, etc. [17]. However, the effects of damage rate in MSIB irradiation have not often been reported, especially when both H and He are present.…”

Section: Introductionmentioning

confidence: 99%

Effect of Damage Rate on the Cavity Swelling of Pure Nickel Irradiated with Triple Ion Beams

Huang

Gao

Liu

et al. 2022

Metals

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He-H synergistic effects influence the performance of structural materials in fusion reactors. Due to the lack of high-intensity fusion neutron sources, multiple ion beam irradiation has been widely used as an emulation method to study its synergistic effects. However, the damage rate under multiple ion beam irradiation is three to four orders of magnitude higher than that under fusion neutron irradiation, and its effect on the cavity swelling is still unclear. In this study, pure nickel was irradiated with single and triple ion beams to ~1 displacements per atom (dpa) at 450 °C. The damage rate ranged from 1.4 × 10−4 to 1.4 × 10−3 dpa/s, with the identical gas-dose ratios of ~400 H appm/dpa and 100 He appm/dpa. Large and isolated cavities formed under single ion irradiation, while triple ion irradiation induced smaller and denser cavities and higher swelling. As the damage rate increased, the cavity size, density, and swelling decreased, due to the constraint of cavity nucleation and growth processes. The effect of damage rate on cavity evolution under triple ion irradiation strongly depends on two competing factors: the enhancement of aggregation and binding of H/He/vacancies, and the enhancement of vacancies–interstitials recombination with increasing damage rate.

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Helium-Hydrogen Synergistic Effects in Structural Materials Under Fusion Neutron Irradiation

Cited by 11 publications

References 63 publications

Dynamic investigations on hydrogen–helium interaction around the vacancy in BCC iron from ab-initio calculations

Dynamic investigations on hydrogen–helium interaction around the vacancy in BCC iron from ab-initio calculations

Features of Helium–Vacancy Complex Formation at the Zr/Nb Interface

Effect of Damage Rate on the Cavity Swelling of Pure Nickel Irradiated with Triple Ion Beams

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