@article{oai:repo.qst.go.jp:00085488,
 author = {Iwakiri, Hirotomo and Watanabe, Yoshiyuki and Sato, Koichi and Kato, Daiji and Yoshiyuki, Watanabe},
 journal = {Nuclear Materials and Energy},
 month = {Mar},
 note = {To understand the interaction of hydrogen isotopes with VC and Cr23C6 precipitates, in reduced-activation
ferritic/martensitic steel (F82H), we have performed first-principles calculations based on density functional
theory. Energy calculations and electron density analysis were performed with a focus on the hydrogen retention
by vacancies in precipitates. The H atoms in the C vacancy in the VC crystal are bound to the surrounding Cr
atoms by relatively weak covalent forces and Coulombic attraction, and up to four H atoms are trapped. In the
case of a Cr vacancy, H atoms are strongly covalently bonded to neighboring C atoms as well as to an interstitial
H atom, capturing up to six H atoms. H atoms in vacancies in Cr23C6 have a weak bonding force with the Cr atom
but a strong repulsive force with the C atom. As a result, H atom is not trapped in the Cr(4a) vacancy, and H
atoms are trapped only at a distance from the C atom in the Cr(48H) and Cr(32f) vacancies. The Cr(8c) and C
vacancies are relatively far from the C atoms and have higher hydrogen trapping energies. The Cr23C6 precipitate
containing vacancies may be a dominant trapping site in the temperature range when H atoms immediately
dissociate from vacancies. In addition, the VC precipitate may be the only trapping site for hydrogen isotopes at
higher temperatures when Cr23C6 precipitates cannot trap them.},
 title = {Interaction of primary precipitates in reduced -activation ferritic/ martensitic steel F82H with hydrogen atoms: Atomistic calculation based on the density functional theory},
 volume = {31},
 year = {2022}
}