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First-Principles Study of the Hydrogen Resistance Mechanism of PuO2
- Source :
- ACS Omega, Vol 5, Iss 13, Pp 7211-7218 (2020), ACS Omega
- Publication Year :
- 2020
- Publisher :
- American Chemical Society, 2020.
-
Abstract
- The in-depth investigation of hydrogen behaviors in Pu-oxide overlayers (mainly PuO2 and α-Pu2O3) is critical for modeling the complex induction period of Pu hydriding. Within density functional theory (DFT) + U + D3 schemes, our systematic first-principles calculations and ab initio thermodynamic evaluations reveal that the hydrogen incorporation, dissolution behaviors, and diffusion mechanism in PuO2 are quite different from those in α-Pu2O3, among which the highly endothermic incorporation and dissolution of hydrogen are the primary hydrogen resistance mechanism of PuO2. Since its difficult recombination, atomic H is the preferred existence state in PuO2, but H will recombine spontaneously in α-Pu2O3. In PuO2, H diffusion is always clinging to O anions, whereas in α-Pu2O3, H2 prefers to migrate along O vacancies with higher barriers. H dissolution in intact PuO2 is very difficult, which can only be driven by extremely high pressure PH2 and temperature. Based on a series of theoretical studies, we conclude that the main interactions between hydrogen and Pu-oxide overlayers are not involved with chemical reactions, and intact PuO2 can effectively inhibit hydrogen permeation.
Details
- Language :
- English
- ISSN :
- 24701343
- Volume :
- 5
- Issue :
- 13
- Database :
- OpenAIRE
- Journal :
- ACS Omega
- Accession number :
- edsair.doi.dedup.....30e2af98d2874f8ae9406acee2c3885c