NSUF 20-4163: Secondary Phase Formation in Irradiated Metallic Fuels: Understanding Phase Structure, Chemistry and Light-Element Stabilization
Metallic fuels remain relevant to the DOE mission due to the fact that several different formulations of UxPuyZrz fuels are intended to be used in Versatile Test Reactor. Despite the long history of metallic fuel use, certain features of these fuels have not been studied with modern analytical microscopes. Secondary phase precipitation of LnxPdyRhz-like phases and UxNpyPuzZr2-like phases in particular have the potential to impact the safety and extended use behavior of metallic fuels through reducing lanthanide transport to the cladding (the LnxPdyRhz-like phase) and altering thermal conductivity (the UxNpyPuzZr2-like phase). This study will analyze these phases in an irradiated U-Pu-Zr fuel with added minor actinides. Shielded electron probe microanalysis (EPMA) will measure chemical composition, including N and O of the secondary phases. Correlation microscopy will be used between the EPMA and the focused ion beam microscope (FIB) so that extracted lamella will come from the analyzed phases. Transmission electron microscopy (TEM) will be used to determine the crystal lattice parameters while scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) will be used to determine the local bonding environment for the light elements in the phases and determine whether the phases are N or O stabilized. To date, light element stabilization of these phases in nuclear fuel has not been demonstrated conclusively. This study will remedy this deficit and increase our understanding of how metallic fuels evolve during irradiation. It will require three weeks of instrument access at Idaho National Laboratory.
Additional Info
| Field | Value |
|---|---|
| Abstract | Metallic fuels remain relevant to the DOE mission due to the fact that several different formulations of UxPuyZrz fuels are intended to be used in Versatile Test Reactor. Despite the long history of metallic fuel use, certain features of these fuels have not been studied with modern analytical microscopes. Secondary phase precipitation of LnxPdyRhz-like phases and UxNpyPuzZr2-like phases in particular have the potential to impact the safety and extended use behavior of metallic fuels through reducing lanthanide transport to the cladding (the LnxPdyRhz-like phase) and altering thermal conductivity (the UxNpyPuzZr2-like phase). This study will analyze these phases in an irradiated U-Pu-Zr fuel with added minor actinides. Shielded electron probe microanalysis (EPMA) will measure chemical composition, including N and O of the secondary phases. Correlation microscopy will be used between the EPMA and the focused ion beam microscope (FIB) so that extracted lamella will come from the analyzed phases. Transmission electron microscopy (TEM) will be used to determine the crystal lattice parameters while scanning transmission electron microscopy-electron energy loss spectroscopy (STEM-EELS) will be used to determine the local bonding environment for the light elements in the phases and determine whether the phases are N or O stabilized. To date, light element stabilization of these phases in nuclear fuel has not been demonstrated conclusively. This study will remedy this deficit and increase our understanding of how metallic fuels evolve during irradiation. It will require three weeks of instrument access at Idaho National Laboratory. |
| Award Announced Date | 2020-07-14T14:10:53.75 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Alina Zackrone |
| Irradiation Facility | None |
| PI | Karen Wright |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 4163 |