Crystal Chemistry of Immobilization of Tetravalent Ce and Se in Ceramic Matrix of Sodium Zirconium Phosphates

Sodium zirconium phosphate (here after NZP) is a typical host material capable of converting the intermediate level waste resulting from light water reactor (LWR) fuel reprocessing into a single-phase material with good stability, high integrity and long durability. The crystal chemistry of NaZr1.9Ce0.1P3O12 and NaZr1.9Se0.1P3O12 phases has been investigated using general structure analysis system programming. The Se/CeNZP phases crystallize in the space group R-3c and Z = 6. Powder diffraction data have been subjected to Rietveld refinement to arrive at a satisfactory structural convergence of R-factors. The Phosphate counter ions stretching and bending vibrations in the infrared (IR) region have been assigned. SEM and EDAX analyses provide evidence of Ce and Se in the matrix.