|About this Abstract
||Materials Science & Technology 2019
||Materials Issues in Nuclear Waste Management
||P3-71: Multi-scale Structural Response of Pyrochlore Oxides to Swift Heavy Ion Irradiation
||Eric O'Quinn, Igor Gussev, William Cureton, Devon Drey, Alex Solomon, Joerg Neuefeind, Maik Lang
|On-Site Speaker (Planned)
A major obstacle to the disposal of high-level nuclear waste is the fabrication of durable materials that can safely immobilize radionuclides. Materials proposed for usage as waste forms in underground repositories must demonstrate stability against self-irradiation of the incorporated actinides as well as chemical durability such that radioisotopes are not leached into the environment. Some proposed ceramic waste forms that adopt the isometric pyrochlore structure (A2B2O7) exhibit excellent radiation tolerance due to accommodation of atomic-scale disordering, yet it is not yet understood how this disordering mechanism proceeds over the sub-nanoscale. Total scattering experiments provide fundamental insight into the multi-scale structural responses of swift-heavy ion irradiated pyrochlores including crystalline-amorphous and order-disorder transformations. Ion-irradiated pyrochlores are characterized by a high degree of local order with similar atomic arrangements in disordered and amorphous cases. These results provide a framework by which pyrochlore oxides can be accurately modeled for the immobilization of nuclear wastes.