Ternary Phase Diagrams that Relate to the Plutonium Immobilization Ceramic

Ebbinghaus, B b ; Krikorian, O H ; Vance, E R ; Stewart, M W

Lawrence Livermore National Laboratory

关键词: Rutile;    Perovskite;    36 Materials Science;    Titanates;    12 Management Of Radioactive Wastes And Non-Racioactive Waster From Nuclear Facilities;   

DOI  :  10.2172/15013284
RP-ID  :  UCRL-ID-143170
RP-ID  :  W-7405-ENG-48
RP-ID  :  15013284

美国|英语

来源: UNT Digital Library

【 摘 要 】

The plutonium immobilization ceramic consists primarily of a pyrochlore titanate phase of the approximate composition Ca{sub 0.97}Hf{sub 0.17}Pu{sub 0.22}U{sub 0.39}Gd{sub 0.24} Ti{sub 2}O{sub 7}. In this study, a series of ternary phase diagrams was constructed to evaluate the relationship of various titanate phases (e.g., brannerite, zirconolite-2M, zirconolite-4M, and perovskite) to pyrochlore titanates, usually in the presence of excess TiO{sub 2} (rutile), and at temperatures in the vicinity of 1350 C. To facilitate the studies, U, Th, and Ce were used as surrogates for Pu in a number of the phase diagrams in addition to the use of Pu itself. The effects of impurity oxides, Al{sub 2}O{sub 3} and MgO, were also studied on pyrochlore (Gd{sub 2}Ti{sub 2}O{sub 7}) and zirconolite (CaHfTi{sub 2}O{sub 7}) mixtures. Either electron microprobe (at Lawrence Livermore National Laboratory) or quantitative SEM-EDS (at Australian Nuclear Science and Technology Organization) were used to evaluate the compositions of the phases.