Influence of Gd Doping on the Structure and Electrochemical Behavior of UO₂

다국어 초록 (Multilingual Abstract)

<P><B>Abstract</B></P> <P>A series of (U<SUB>1−<I>y</I> </SUB>Gd<I> <SUB>y</SUB> </I>)O<SUB>2</SUB> materials (<I>y</I> =0, 0.01, 0.03, 0.05, 0.07 and 0.10) were characterized by X-ray diffractometry and Raman spectroscopy to determine the influence of Gd<SUP>III</SUP> doping on the structure of (U<SUB>1−<I>y</I> </SUB>Gd<I> <SUB>y</SUB> </I>)O<SUB>2</SUB> solid solutions. The XRD results show that, while the fluorite structure is maintained, Gd doping up to 10% leads to a contraction of the fluorite lattice. Raman spectroscopy shows Gd<SUP>III</SUP> doping distorts the fluorite lattice structure due to the formation of oxygen vacancies (O<SUB>v</SUB>) and, possibly, MO<SUB>8</SUB>-type complexes, as a consequence of the differences in both the oxidation state and the ionic radius of Gd<SUP>3+</SUP> compared to that of the U<SUP>4+</SUP>. The influence of Gd doping on the electrochemical reactivity of the (U<SUB>1−<I>y</I> </SUB>Gd<I> <SUB>y</SUB> </I>)O<SUB>2</SUB> specimens was shown to be minor, possibly due to a competition between the increase in the number of O<SUB>v</SUB> and the contraction of the lattice.</P>