Preparation and characterization of cerium-gadolinium monazites as ceramics for the conditioning of minor actinides. (May 2016)

• Record Type: Journal Article
• Authors: Meng, Cheng; Ding, Xingeng; Zhao, Junchuan; Li, Wenqi; Ren, Chunrong; Yang, Hui
• Is Part Of: Progress in nuclear energy. Volume 89(2016:May)
• Page Start: 1
• Page End: 6
• Publication Date: 2016-05
• Subjects: Phosphates -- Rietveld refinement -- Crystal structure -- Waste forms -- Minor actinide immobilization; Nuclear energy -- Periodicals; Nuclear engineering -- Periodicals; 333.7924
• DOI: 10.1016/j.pnucene.2016.01.021
• Languages: English
• ISSNs: 0149-1970

Abstract

Abstract: Monazites are of considerable interest for immobilization of minor actinides. In this work, the Gd1-x Cex PO4 (0 ≤ x ≤ 1) series is synthesized via conventional solid–state reaction using Ce as the surrogate for minor actinide americium (Am), with microstructure/phase structure characterized by XRD, HRTEM, μ-Raman, and SEM as well. The optimized temperature for preparation of monazite-type Gd0.4 Ce0.6 PO4 solid solution is more than 1300 °C. At 1400 °C, the GdPO4 ceramic is essentially monazite with little metastable xenotime phase. The metastable xenotime (GdPO4 ) to monazite transformation occurs during the immobilizing phase of Ce element. The formation of monazite-type Gd1-x Cex PO4 solid solutions in the range 0.1 ≤ x ≤ 1 is confirmed by the Rietveld refinement and Raman spectra. The change of Ce content has no significant influence on the morphology of the monazite-type Gd1-x Cex PO4 compounds. Highlights: The optimized condition for synthesis of Gd0.4 Ce0.6 PO4 solid solution is investigated. Xenotime (GdPO4 ) to monazite transition occurs during the immobilization of Ce element. Monazite-type Gd1-x Cex PO4 solid solutions form in the range 0.1 ≤ x ≤ 1. Monazite could be considered as a plausible host for minor actinide americium.