Impurity migration and effects on vacancy formation enthalpy in polycrystalline depleted uranium

JOURNAL OF NUCLEAR MATERIALS

卷:466

Article

Lund, K. R.¹  Lynn, K. G.¹  Weber, M. H.¹  Macchi, C.^2,3  Somoza, A.^2,4  Juan, A.^3,5,6  Okuniewski, M. A.⁷ 

[1] Washington State Univ, Ctr Mat Res, Pullman, WA 99163 USA

[2] CIFICEN CONICET UNCPBA, Inst Fis Mat Tandil, Tandil, Argentina

[3] Consejo Nacl Invest Cient & Tecn, RA-1033 Buenos Aires, DF, Argentina

[4] CICPBA, Buenos Aires, DF, Argentina

[5] UNS CONICET, Inst Fis Sur IFISUR, Bahia Blanca, Buenos Aires, Argentina

[6] Univ Nacl Sur, Dept Fis, RA-8000 Bahia Blanca, Buenos Aires, Argentina

[7] EG&G Idaho Inc, Idaho Natl Engn Lab, Idaho Falls, ID 83401 USA

关键词: Positrons;    Formation enthalpy;    Depleted uranium;    Antimatter;    Materials properties;    Annihilation;    Positron annihilation spectroscopy;   

DOI  :  10.1016/j.jnucmat.2015.08.014

来源: Elsevier

【 摘 要 】

We have used Doppler-broadening of the positron-electron annihilation radiation technique and VASP calculations to verify the previously reported vacancy formation enthalpy H-v(f) in polycrystalline depleted uranium. Experimentally we have confirmed a H-v(f) of (1.6+/-0.2) eV. VASP calculations using GGA and LDA approximations gave vacancy formation enthalpies values of 1.98 eV and 2.22 eV respectively. We found residual oxygen in the sample diminished these values by 50% or more. Our new experimental and theoretical data supports the notion that oxygen impurities in the sample are responsible for lower values of vacancy formation enthalpies. Measured and calculated vacancy formation enthalpies, as well as the obtained oxygen migration enthalpy of (0.6 +/- 0.1) eV, are compared and discussed with values reported in the literature. (C) 2015 Published by Elsevier B.V.

【 授权许可】

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