Irradiation of plutonium tributyl phosphate complexes by ionizing alpha particles: a computational study
Résumé
The PUREX solvent extraction process is widely used for recovering uranium and
plutonium from spent nuclear fuel, it uses an organic solvent made up of TriButyl
Phosphate (TBP). The emission of ionizing particles such as alpha particles, result-
ing from the decay of plutonium, make the organic solvent vulnerable to degradation.
Here, we study the ultra-short time alpha irradiation of tributylphosphate (TBP) and
Pu(NO3)4(TBP)2 complex formed in the PUREX process. Electron dynamics is prop-
agated by Real-Time Time-Dependent Auxiliary Density Functional Theory (RT-TD-
ADFT). We investigate the use of previously proposed Complex Absorbing Potentiel
(CAP) in energy space to treat secondary electron emission. Basis set and exchange
correlation functionals effects with CAP are reported as well as a detailed analysis of
the CAP parametrisation. Preliminary results on water molecule and then on TBP
show that the phenomenological nature of the CAP parameters induces an adapted
choice of their values for each studied system. Irradiation of free and complexed TBP
shows an influence of the ligands in the variation of atomic charges at the femtosecond
time scale. An accumulation of atomic charges in the alkyl chains of TBP is observed
in the case where the nitrate groups are predominantly irradiated.
Domaines
Chimie théorique et/ou physiqueOrigine | Fichiers produits par l'(les) auteur(s) |
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