Structural characterization of Nd-doped Hf-zirconolite Ca1-xNdxHfTi2-xAlxO7 ceramics

被引:52
作者
Caurant, Daniel [1 ]
Loiseau, Pascal [1 ]
Bardez, Isabelle [1 ]
机构
[1] Chim ParisTech ENSCP, CNRS, Lab Chim Mat Condensee Paris, UMR 7574, F-75231 Paris, France
关键词
LEVEL NUCLEAR-WASTE; RADIATION-DAMAGE; PU DISPOSITION; SIO2-AL2O3-CAO-ZRO2-TIO2; GLASSES; CANDIDATE TITANATES; ACTINIDE FRACTION; LANTHANIDES CE; PLUTONIUM; CRYSTALLIZATION; IMMOBILIZATION;
D O I
10.1016/j.jnucmat.2010.09.033
中图分类号
T [工业技术];
学科分类号
08 ;
摘要
Because of its high incorporation capacity and of the high thermal neutron capture cross-section of hafnium Hf-zirconolite (CaHfTi2O7) ceramic can be envisaged as a potential waste form for minor actinides (Np Am Cm) and plutonium immobilization In this work Nd-doped Hf-zirconolite Ca1-xNdxHfTi2-xAlxO7 (x = 0 001 and 0 2) ceramics have been prepared by solid state reaction Neodymium has been used as trivalent actinide surrogate The ceramic samples structure has been studied by X-ray diffraction and refined by the Rietveld method This revealed that Nd3+ ions only enter the Ca site whereas part of Hf4+ ions substitute titanium into) sites and Al3+ ions mainly occupy the Ti(2) split sites and Ti(3) sites of the zirconolite structure Using various spectroscopic techniques (electron spin resonance optical absorption and fluorescence) the environment of Nd3+ canons in Hf-zirconolite has been studied and compared with that of Nd3+ cations in Zr zirconolite (CaZrTi2O7) Different local environments of Nd3+ canons have been detected in Hf-zirconolite that can be attributed to the existence of an important disorder around Nd in the Ca site probably due to the statistical occupancy of the next nearest cationic site of neodymium (a split Ti site) by Ti4+ Al3+ cations and vacancies No significant differences were observed concerning Nd3+ cations environment and distribution in Hf- and Zr-zirconolite ceramics (C) 2010 Elsevier B V All rights reserved
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页码:88 / 99
页数:12
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