NSUF 10-269: High Temperature In-pile Irradiation Test of Single Phase U3Si2
High density uranium inter-metallic compound uranium silicide (U3Si2) has attracted much attention as a potential nuclear fuel due to several advantages it demonstrates in thermophysical properties, chemical and irradiation stability. It has a high density of 12.2 g/cm3, high thermal conductivity (15 W/m.K at 27°C), reasonable melting point (~1665°C), adequate water corrosion resistance, and low radiation induced swelling rate (~5% at a fission density of 2x10^21/cm3). Due to these advantages, U3Si2 has been used in research and test reactors and operated at a temperature usually lower than 200°C. Since the commercial power reactors are operating at a much higher temperature than research and test reactors, the high temperature in-pile irradiation behavior of U3Si2 becomes a key evaluation factor for the utilization of U3Si2 as nuclear fuel. Therefore, the research goal for the proposed work is to characterize and understand the high temperature in-pile irradiation behavior of U3Si2. Specifically, the areas that need to be studied and understood in the proposed work are listed here: high temperature swelling behavior of U3Si2, irradiation induced microstructural evolution, mechanical integrity and fuel pellet cracking, fission gas release, changes in stoichiometry and hardness of U3Si2 after radiation, chemical stability against water during irradiation, and behavior under ramp test conditions. Based on the project objectives, we propose to perform in-pile irradiation test of U3Si2 at the three different temperatures: 300, 750 and 1200°C. The temperature of the fuel will be controlled both by the Ar/He ratio and the gap size between the cladding and the fuel pellets. Through enrichment adjustment, the U3Si2 fuel pellets will be irradiated at various power rates from 5 to 30 kW/ft. The target fission density is between 7.59 and 9.49x10^20 fissions/cm3. In order to accomplish the objectives in the proposed work, the following PIE methods are suggested: Neutron Radiography, Element/capsule Visual Inspection, Element Contact Profilometry, Metallography, Scanning Electron Microscopy (SEM/EDS/WDS), Fission Gas Measurement and Analysis, Microhardness Measurement, Chemical Analysis, and Transmission Electron Microscopy (TEM/EDS). The knowledge gained on the high temperature in-pile irradiation behavior of U3Si2 from the proposed work is of importance to the fundamental study of material science. Because the high temperature in-pile irradiation behavior of U3Si2 has never been studied, this proposed work will fill the gap. It is anticipated that the pellets will swell under irradiation. The swelling of U3Si2 will be correlated to the fission gas formation and fission products retention, as well as microstructural and structural evolution. It is expected that the depletion of uranium through fission will affect the U/Si ratio in U3Si2. Such an effect has not yet been investigated at LWR reactor conditions for U3Si2, but will be studied and addressed as one of the key issues in this proposed work. Furthermore, no one has yet generated performance data using U3Si2 in a single phase pellet form, but only as small particles in an aluminum matrix; in the proposed work, the irradiation performance of single phase U3Si2 fuel will be studied and contrasted to the dispersed type U3Si2 fuel performed by previous researchers. The proposed experiment and subsequently obtained results will indeed improve the current understanding of irradiation behavior of U3Si2.
Additional Info
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|---|---|
| Abstract | High density uranium inter-metallic compound uranium silicide (U3Si2) has attracted much attention as a potential nuclear fuel due to several advantages it demonstrates in thermophysical properties, chemical and irradiation stability. It has a high density of 12.2 g/cm3, high thermal conductivity (15 W/m.K at 27°C), reasonable melting point (~1665°C), adequate water corrosion resistance, and low radiation induced swelling rate (~5% at a fission density of 2x10^21/cm3). Due to these advantages, U3Si2 has been used in research and test reactors and operated at a temperature usually lower than 200°C. Since the commercial power reactors are operating at a much higher temperature than research and test reactors, the high temperature in-pile irradiation behavior of U3Si2 becomes a key evaluation factor for the utilization of U3Si2 as nuclear fuel. Therefore, the research goal for the proposed work is to characterize and understand the high temperature in-pile irradiation behavior of U3Si2. Specifically, the areas that need to be studied and understood in the proposed work are listed here: high temperature swelling behavior of U3Si2, irradiation induced microstructural evolution, mechanical integrity and fuel pellet cracking, fission gas release, changes in stoichiometry and hardness of U3Si2 after radiation, chemical stability against water during irradiation, and behavior under ramp test conditions. Based on the project objectives, we propose to perform in-pile irradiation test of U3Si2 at the three different temperatures: 300, 750 and 1200°C. The temperature of the fuel will be controlled both by the Ar/He ratio and the gap size between the cladding and the fuel pellets. Through enrichment adjustment, the U3Si2 fuel pellets will be irradiated at various power rates from 5 to 30 kW/ft. The target fission density is between 7.59 and 9.49x10^20 fissions/cm3. In order to accomplish the objectives in the proposed work, the following PIE methods are suggested: Neutron Radiography, Element/capsule Visual Inspection, Element Contact Profilometry, Metallography, Scanning Electron Microscopy (SEM/EDS/WDS), Fission Gas Measurement and Analysis, Microhardness Measurement, Chemical Analysis, and Transmission Electron Microscopy (TEM/EDS). The knowledge gained on the high temperature in-pile irradiation behavior of U3Si2 from the proposed work is of importance to the fundamental study of material science. Because the high temperature in-pile irradiation behavior of U3Si2 has never been studied, this proposed work will fill the gap. It is anticipated that the pellets will swell under irradiation. The swelling of U3Si2 will be correlated to the fission gas formation and fission products retention, as well as microstructural and structural evolution. It is expected that the depletion of uranium through fission will affect the U/Si ratio in U3Si2. Such an effect has not yet been investigated at LWR reactor conditions for U3Si2, but will be studied and addressed as one of the key issues in this proposed work. Furthermore, no one has yet generated performance data using U3Si2 in a single phase pellet form, but only as small particles in an aluminum matrix; in the proposed work, the irradiation performance of single phase U3Si2 fuel will be studied and contrasted to the dispersed type U3Si2 fuel performed by previous researchers. The proposed experiment and subsequently obtained results will indeed improve the current understanding of irradiation behavior of U3Si2. |
| Award Announced Date | 2010-06-09T00:00:00 |
| Awarded Institution | Center for Advanced Energy Studies |
| Facility | Microscopy and Characterization Suite |
| Facility Tech Lead | Alina Zackrone, Yaqiao Wu |
| Irradiation Facility | None |
| PI | Darryl Butt |
| PI Email | [email protected] |
| Project Type | Irradiation/PIE |
| RTE Number | 269 |