Crystalline compounds for remediation of rare-earth fission products: A review
Rare-earth (RE) containing crystals have been investigated as media for the immobilization of RE fission products. During reprocessing of spent nuclear fuels, various fission products including REs, alkalis, and alkaline earths are found after the extraction of actinides. One viable option to immobilize the RE fission products is to incorporate them into chemically durable crystalline phases in specific waste forms. This study summarizes the crystal structures and synthesis methods of six RE-containing compounds that have applications in remediation of RE fission products. These compounds include oxyapatite [Ca2RE8(SiO4)6O2], oxychloride [REOCl], borosilicate [RE3BSi2O10], pyrochlore [RE2A2O7], monazite [REPO4], and perovskite [REAO3] where A denotes transitional metals. This review provides an overview of literature on the usage of these six compounds for immobilizing RE fission products and summarizes different synthesis methods for producing these compounds. Comparisons of structural parameters with different REs in each compound are also discussed.
Published: June 16, 2022
Chong S., B.J. Riley, and Z.J. Nelson. 2022.Crystalline compounds for remediation of rare-earth fission products: A review.Journal of Rare Earths 40, no. 3:365-380.PNNL-SA-156271.doi:10.1016/j.jre.2021.01.016