Deuterium diffusion in γ-LiAlO2 pellets irradiated with He+ and D2+ ions

JOURNAL OF NUCLEAR MATERIALS

卷:538

Article

Jiang, Weilin¹  Wang, Tianyao²  Wang, Yining¹  Zhu, Zihua¹  Shao, Lin²  Senor, David J.¹ 

[1] Pacific Northwest Natl Lab, Richland, WA 99354 USA

[2] Texas A&M Univ, Dept Nucl Engn, College Stn, TX 77843 USA

关键词: Deuterium diffusion;    Ion irradiation;    Tritium breeder material;    LiAlO2;   

DOI  :  10.1016/j.jnucmat.2020.152357

来源: Elsevier

【 摘 要 】

Sequential irradiations of polycrystalline gamma-LiAlO2 pellets were performed at 573 K with He+ and D-2(+) ions to overlap the deuterium (D) profile with the He+ ion damage peak. The D depth profiles were measured using time-of-flight secondary ion mass spectrometry before and after thermal annealing steps. A linear concentration gradient approximation model is proposed to estimate the diffusion coefficient. The combined isothermal and isochronal data are used to determine the activation energy for D migration. At and above 1 x 10(17) He++D+/cm(2), a double-peak structure in the D profile is observed probably due to isotope exchange reactions with H2O and H2. The D diffusion coefficient in the irradiated gamma-LiAlO2 pellets is on the order of 10(-12) cm(2)/ s at 773 K for the first 2min annealing and the average values between 5 and 60 min tend to decrease to 10(-13) or 10(-14) cm(2)/s, depending on the ion fluence. The activation energy for D migration is determined to be 1.0 +/- 0.3 eV at 2 x 10(16) He++D+/cm(2) and 0.6 +/- 0.3 eV at 1 x 10(17) He++D+/cm(2). The results from this study may help better understand and predict tritium diffusion behavior during neutron irradiation of gamma-LiAlO2 pellets. (c) 2020 Elsevier B.V. All rights reserved.

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