Actinide incorporation in a zirconia based pyrochlore (Nd(1.8)An(0.2))Zr2O7+x (An = Th, U, Np, Pu, Am)
Artikel i vetenskaplig tidskrift, 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.

Zirconia

Pyrochlore

Transmutation

transmutation

near-edge structure

stabilized zirconia

x-ray-absorption

Nuclear waste disposal

crystal-chemistry

Conditioning

spectroscopy

plutonium

uranium

EXAFS

nuclear-waste

Minor actinides

phase

Författare

Catharina Nästrén

Chalmers, Kemi- och bioteknik, Kärnkemi

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

Karlsruher Institut für Technologie (KIT)

Journal of Solid State Chemistry

0022-4596 (ISSN) 1095-726X (eISSN)

Vol. 182 1 1-7

DOI

10.1016/j.jssc.2008.09.017