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Multiscale structural characterizations of mixed U(IV)-An(III) oxalates (An(III) = Pu or Am) combining XAS and XRD measurements
被引:9
|作者:
Arab-Chapelet, B.
[1
]
Martin, M.
[2
]
Costenoble, S.
[1
]
Delahaye, T.
[1
]
Scheinost, A. C.
[3
]
Grandjean, S.
[1
]
Abraham, F.
[4
]
机构:
[1] CEA, DEN, DRCP, SERA,Lab Convers Actinides & Radiolyse, BP 17171, F-30207 Bagnols Sur Ceze, France
[2] CEA, DEN, DEC, F-13108 St Paul Les Durance, France
[3] Helmholtz Zentrum Dresden Rossendorf, Inst Resource Ecol, D-01314 Dresden, Germany
[4] Univ Lille Nord France, Unite Catalyse & Chim Solide, UMR CNRS 8181, ENSCL USTL, BP 90108, F-59652 Villeneuve Dascq, France
关键词:
X-RAY;
FUEL FABRICATION;
UMACS PROCESS;
IONIC-RADII;
AMERICIUM;
PR;
LN;
COMPLEXES;
U(IV);
ND;
D O I:
10.1039/c5dt04312c
中图分类号:
O61 [无机化学];
学科分类号:
070301 ;
081704 ;
摘要:
Mixed actinide(III, IV) oxalates of the general formula M(2.2)U(1.8)(IV)An(0.2)(III)(C2O4)(5)center dot nH(2)O (An = Pu or Am and M = H3O+ and N2H5+) have been quantitatively precipitated by oxalic precipitation in nitric acid medium (yield >99%). Thorough multiscale structural characterization using XRD and XAS measurements confirmed the existence of mixed actinide oxalate solid solutions. The XANES analysis confirmed that the oxidation states of the metallic cations, tetravalent for uranium and trivalent for plutonium and americium, are maintained during the precipitation step. EXAFS measurements show that the local environments around U+IV, Pu+III and Am+III are comparable, and the actinides are surrounded by ten oxygen atoms from five bidentate oxalate anions. The mean metal-oxygen distances obtained by XAS measurements are in agreement with those calculated from XRD lattice parameters.
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页码:6909 / 6919
页数:11
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