NSUF 19-1743: High-burnup U-Mo pore morphology analysis as a function of fission density and rate
Fission product swelling of the nuclear fuel causing closure of the coolant gaps is one of the main failure modes of these material systems. Solid fission product swelling has shown linear relationship with irradiation yet only empirical models exist for the role of fission gasses in swelling. This project proposes characterizing a nuclear fuel plate at several locations of a single irradiated U-Mo fuel plate with varying fission density using 2D and then future 3D methods to have an increase in understanding of the role of fission density/rate on pore morphology in a γ matrix. An edge on high burnup U-Mo fuel plate creates a unique opportunity to isolate the role of fission density/rate on pore morphology due to its stable γ-U phase, uniform temperature and power. At high burnup, LEU fuel plates have completed recrystallization to a nano-grain microstructure. This increase in grain boundary density, increases the fission gas mobility in the γ matrix, removing grain-boundary preferential nucleation of pores. This allows the characterization of pore morphology solely as a function of fission rate/density and not as a function of grain position. Comparisons to other fuel types where fission gas mobility is higher due to higher operating temperature can also be compared. Therefore, the goal of this work is to take advantage of the fission density variation in U-Mo fuel plates to characterize pore morphology solely as a function of fission density/rate. From this data, observations of nucleation rate and pore mobility can be obtained and can give insight on possible failure modes in these areas. FIB cubes will be taken in these locations to do tomography analysis. SE and BSE images and EDS scans will be conducted around the FIB cube locations. Taking FIB cubes in these locations will allow for three-dimensional (3D) microstructures to be obtained to enhance the data. 3D microstructure analysis will help fully understand the pore morphology due to the anisotropy of interconnected porosity. Therefore, future work will be done on the FIB cubes such as synchrotron tomography analysis at APS for three-dimensional porosity characterization.
Additional Info
| Field | Value |
|---|---|
| Abstract | Fission product swelling of the nuclear fuel causing closure of the coolant gaps is one of the main failure modes of these material systems. Solid fission product swelling has shown linear relationship with irradiation yet only empirical models exist for the role of fission gasses in swelling. This project proposes characterizing a nuclear fuel plate at several locations of a single irradiated U-Mo fuel plate with varying fission density using 2D and then future 3D methods to have an increase in understanding of the role of fission density/rate on pore morphology in a γ matrix. An edge on high burnup U-Mo fuel plate creates a unique opportunity to isolate the role of fission density/rate on pore morphology due to its stable γ-U phase, uniform temperature and power. At high burnup, LEU fuel plates have completed recrystallization to a nano-grain microstructure. This increase in grain boundary density, increases the fission gas mobility in the γ matrix, removing grain-boundary preferential nucleation of pores. This allows the characterization of pore morphology solely as a function of fission rate/density and not as a function of grain position. Comparisons to other fuel types where fission gas mobility is higher due to higher operating temperature can also be compared. Therefore, the goal of this work is to take advantage of the fission density variation in U-Mo fuel plates to characterize pore morphology solely as a function of fission density/rate. From this data, observations of nucleation rate and pore mobility can be obtained and can give insight on possible failure modes in these areas. FIB cubes will be taken in these locations to do tomography analysis. SE and BSE images and EDS scans will be conducted around the FIB cube locations. Taking FIB cubes in these locations will allow for three-dimensional (3D) microstructures to be obtained to enhance the data. 3D microstructure analysis will help fully understand the pore morphology due to the anisotropy of interconnected porosity. Therefore, future work will be done on the FIB cubes such as synchrotron tomography analysis at APS for three-dimensional porosity characterization. |
| Award Announced Date | 2019-05-14T16:15:44.22 |
| Awarded Institution | None |
| Facility | None |
| Facility Tech Lead | Alina Zackrone |
| Irradiation Facility | None |
| PI | Alejandro Figueroa |
| PI Email | [email protected] |
| Project Type | RTE |
| RTE Number | 1743 |