Novel Plutonium Titanate Compounds and Solid Solutions Pu₂Ti₂O₇‐Ln₂Ti₂O₇: Relevance to Nuclear Waste Disposal

Abstract

The compounds SrPu2Ti4O12, Pu2Ti3O8.79, and Pu2Ti2O7, where plutonium is in the (III) oxidation state, were prepared and identified via X‐ray diffraction (XRD). The solid solubility limit of Pu2Ti2O7 in Ln2Ti2O7 (Ln = Gd, Er, or Lu) was also studied via XRD; it was determined that the solubility of Pu2Ti2O7 increased as the radius of the lanthanide ion in the host compound decreased. Attempts to synthesize Sr2Pu2 Ti5O16 and Sr2Ce2–yPuyTi5O16 solid solutions, where plutonium is in the (IV) oxidation state, were unsuccessful.

Ion beam irradiation of U-, Th- and Ce-doped pyrochlores

“…Isometric pyrochlores, A 2 B 2 O 7 , have been proposed as potential hosts for the immobilization of actinides, particularly Pu, due to their chemical durability and their ability to accommodate a wide variety of waste stream compositions [1][2][3][4][5][6][7]. The self-irradiation effects from the ␣-decay events of the incorporated actinides in the transplutonium-zirconate pyrochlores An 2 Zr 2 O 7 (An = Am, Cf) have recently been reported [8].…”

Energy band gap and dispersive optical parameters in Bi1.5Zn0.92Nb1.5O6.92 pyrochlore ceramics

“…For example, Cd 2 Nb 2 O 7 and Ln 2 Ti 2 O 7 pyrochlore ceramics are used in the design of electronic devices. Moreover, due to their refractory properties and good chemical resistivity, they have been used as nuclear waste matrices [8,9]. Furthermore, Due to their temperature stability, low-loss and high permittivity, bismuth-based pyrochlore ceramics, are reported to be promising materials to be used as highfrequency filters and multilayer devices [10][11][12][13][14][15].…”

The solubility of cerium in La2Ti2O7 by DFT + U calculations

“…Furthermore, the solubility of Pu in titanate pyrochlores has been studied by Shoup et al [8].They prepared and identified Pu 2 Ti 2 O 7 via X-ray diffraction and estimated the solubility limit of Pu 2 Ti 2 O 7 in A 2 Ti 2 O 7 (A=…”

“…Numerous experimental and theoretical efforts have been made to investigate the properties and the radiation resistance of them [3,5,7,8,13,[19][20][21][22][23][24].…”

“…In recent years, there has been great interest in using materials with fluorite-related structures as host phase for the immobilization of plutonium and "minor" actinides [2,[4][5][6][7][8][9][10][11][12]. Pyrochlore compounds are closely related to the fluorite-structure (AX 2 ), except that there are two cation sites and one-eighth of the anions are absent.…”