Author/Authors :
Gregg، نويسنده , , Daniel J. and Zhang، نويسنده , , Yingjie and Middleburgh، نويسنده , , Simon C. and Conradson، نويسنده , , Steven D. and Triani، نويسنده , , Gerry and Lumpkin، نويسنده , , Gregory R. and Vance، نويسنده , , Eric R.، نويسنده ,
Abstract :
The incorporation of plutonium (Pu) within lanthanum zirconate pyrochlore was investigated using air, argon, and N2–3.5%H2 sintering atmospheres together with Ca2+ and Sr2+ incorporation for charge compensation. The samples have been characterised in the first instance by X-ray diffraction (XRD), scanning electron microscopy (SEM) and diffuse reflectance spectroscopy (DRS). The results show Pu can be exchanged for La3+ on the A-site with and without charge compensation and for Zr4+ on the B-site. DRS measurements were made over the wavenumber range of 4000–19,000 cm−1 and the Pu in all air- and argon-sintered samples was found to be present as Pu4+ while that in samples sintered in N2–3.5%H2 was present as Pu3+. The Pu valence was confirmed for three of the samples using X-ray near-edge absorption spectroscopy (XANES). Pu valences >4+ were not observed in any of the samples.
