Actinide incorporation in a zirconia based pyrochlore (Nd(1.8)An(0.2))Zr2O7+x (An = Th, U, Np, Pu, Am)
Journal article, 2009
Actinides (thorium, uranium, neptunium, plutonium, and americium) were infiltrated into a porous Nd1.8Zr2O6.7 matrix, prepared by gel-supported precipitation. (Nd(1.8)An(0.2))Zr2O7+x pyrochlores were formed after sintering in Ar/H-2 and the pyrochlore structure remains during oxidation at 800 degrees C in air. X-ray diffraction reveals a linear relationship between the pyrochlore lattice parameter and the ionic radii of the actinides. EXAFS measurements on actinide L-3-edge show a split shell of nearest neighbour oxygen atoms similar to that Surrounding of Nd. The actinide-oxygen bond distances decrease with the actinide ionic radii, which verifies that these actinides adopt the Nd site in the (Nd(1.8)An(0.2))Zr2O7+x pyrochlore. The oxidation susceptibility of Np is related to the availability of oxygen vacancies and in contrast to stabilised zirconia Np(V) can be obtained in zirconia based pyrochlore. (C) 2008 Elsevier Inc. All rights reserved.
transmutation
Minor actinides
Pyrochlore
x-ray-absorption
Transmutation
crystal-chemistry
uranium
Nuclear waste disposal
stabilized zirconia
nuclear-waste
spectroscopy
near-edge structure
plutonium
EXAFS
Zirconia
phase
Conditioning
Author
Catharina Nästrén
Chalmers, Chemical and Biological Engineering, Nuclear Chemistry
R. Jardin
European Commission Joint Research Centre, Institute for Transuranium Elements Karlsruhe
J. Somers
European Commission Joint Research Centre, Institute for Transuranium Elements Karlsruhe
M. Walter
European Commission Joint Research Centre, Institute for Transuranium Elements Karlsruhe
B. Brendebach
Karlsruhe Institute of Technology, Campus North
Journal of Solid State Chemistry
0022-4596 (ISSN) 1095-726X (eISSN)
Vol. 182 1 1-7DOI
10.1016/j.jssc.2008.09.017