Oxygen Potentials of Pyrochlore‐Type Am₂Zr₂O_7+y

Abstract

The relations between the oxygen potentials and the excess oxygen-nonstoichiometry (y) of the pyrochlore-type Am 2 Zr 2 O 7+y at 1333 K were measured by the electrochemical method using a zirconia solid electrolyte and the change of mass by oxidation and reduction. The oxygen potentials at 1333 K smoothly increased from À516.5 to 0.00 kJ/mol with increasing y from 0.00 to 0.56. It was found that the oxygen potentials of Am 2 Zr 2 O 7+y were higher than those of AmO 2Àx and Am 0.5 Np 0.5 O 2Àx measured in our previous studies at 1333 K. The results were discussed with the valence state and ionic radius of cations as well as the phase relations.C. Jantzen-contributing editor Manuscript No. 28742.

Preparation and chemical stability evaluation of Ln2Zr2O7‐SrZrO3 novel composite ceramics cured simultaneously with An and 90Sr

“…Zirconium-based pyrochlore A 2 Zr 2 O 7 (A = Ln or An) is recognized as the most ideal candidate for immobilization of An nuclide due to its strongest radiation resistance, good chemical durability, and large nuclide encapsulation capacity. [1][2][3][4] The successive synthesis of 241 Am 2 Zr 2 O 7 5,6 and 238 Pu 2 Zr 2 O 7 [7][8][9] and the experimental results that the structure of 241 Am 2 Zr 2 O 7 10 without degenerate at 0.21 dpa self-irradiation dose further confirmed that A 2 Zr 2 O 7 was the best host of An nuclide. To reveal the mechanism of excellent comprehensive perfor-mance of A 2 Zr 2 O 7 , the irradiation stability of waste form in the Gd 2 (Ti x Zr 1-x ) 2 O 7 system was evaluated through irradiation experiments.…”