NSUF 16-602: Plastic Deformation and Compositional Changes within Irradiated Alpha-Uranium Metal Particles in ZirconiumHydride Matrix Fuels
Reactor irradiation is known to induce restructuring, phase changes, and defect formation in alpha uranium. The early-time volume change of hydride fuel, as reported many decades ago (Balooch and Hamza, 1996) suggests large increases at temperature greater than 700°C as determined by density measurements of the irradiated specimens. The microscopic examination of the swollen hydride fuel revealed large cavities adjacent to uranium particles. These cavities were believed to be true voids, not fission-gas bubbles, presumably generated by the irradiation damage created by escaping fission fragments. This so-called “early” swelling is to be avoided here by the LM filled gap that reduces the maximum temperature. However, long-term swelling due to solid-fission product accumulation has still been reported to be three times faster in hydride fuel than oxide fuel. This is potentially a very disadvantageous feature of hydride fuels compared to oxides. These changes may be investigated readily with TEM and with the added capability of FIB-SEM slice and view, specific regions of interest can be easily examined. These radiation induced processes will also occur in the U-particles in the Zr-hydride fuel and may play a role in subsequent behavior in-reactor. With shorter irradiations, damage can be less visible and requires more specialized tools, such as SEM-FIB and TEM. Initial SEM results from the examination of irradiated metal micro-particles show little obvious changes. Although analysis of the entire specimen revealed a number of interesting findings, including, Zr-LM interaction and LM phase separation. With TEM we will examine fission product accumulation, defects, or voids. We propose over a period of three months to examine the U-particles and the interface between the U-particles and the Zr-hydride matrix material and compare the results to predictions. The research will result in research papers that will be published in the Journal of Nuclear Materials. Explain and predict U-particle performance and validate predictions. The proposed experiments have not been conducted previously on these types of materials and would highlight innovative concepts for characterizing and examining nuclear materials. The work would enable development of more fundamental understanding of the irradiation behavior of metal particulate fuel and would be relevant to other fuel forms including dispersion fuels. The data produced will be published in the scientific literature.
Additional Info
| Field | Value |
|---|---|
| Abstract | Reactor irradiation is known to induce restructuring, phase changes, and defect formation in alpha uranium. The early-time volume change of hydride fuel, as reported many decades ago (Balooch and Hamza, 1996) suggests large increases at temperature greater than 700°C as determined by density measurements of the irradiated specimens. The microscopic examination of the swollen hydride fuel revealed large cavities adjacent to uranium particles. These cavities were believed to be true voids, not fission-gas bubbles, presumably generated by the irradiation damage created by escaping fission fragments. This so-called “early” swelling is to be avoided here by the LM filled gap that reduces the maximum temperature. However, long-term swelling due to solid-fission product accumulation has still been reported to be three times faster in hydride fuel than oxide fuel. This is potentially a very disadvantageous feature of hydride fuels compared to oxides. These changes may be investigated readily with TEM and with the added capability of FIB-SEM slice and view, specific regions of interest can be easily examined. These radiation induced processes will also occur in the U-particles in the Zr-hydride fuel and may play a role in subsequent behavior in-reactor. With shorter irradiations, damage can be less visible and requires more specialized tools, such as SEM-FIB and TEM. Initial SEM results from the examination of irradiated metal micro-particles show little obvious changes. Although analysis of the entire specimen revealed a number of interesting findings, including, Zr-LM interaction and LM phase separation. With TEM we will examine fission product accumulation, defects, or voids. We propose over a period of three months to examine the U-particles and the interface between the U-particles and the Zr-hydride matrix material and compare the results to predictions. The research will result in research papers that will be published in the Journal of Nuclear Materials. Explain and predict U-particle performance and validate predictions. The proposed experiments have not been conducted previously on these types of materials and would highlight innovative concepts for characterizing and examining nuclear materials. The work would enable development of more fundamental understanding of the irradiation behavior of metal particulate fuel and would be relevant to other fuel forms including dispersion fuels. The data produced will be published in the scientific literature. |
| Award Announced Date | 2015-12-16T00:00:00 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Stuart Maloy |
| Irradiation Facility | None |
| PI | Edgar Buck |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 602 |