To increase the safety and efficiency of nuclear reactors, U3Si2 fuel pellets are being considered as an alternative to traditional UO2. While U3Si2 offers advanced mechanical benefits compared to UO2, leakage fuel rod situations are still hazardous due to lack of resistance to steam from both U3Si2 and UO2. Therefore, to protect and lengthen the lifetime of the fuel pellets, effective corrosion barrier coatings and methods are being investigated.
Glass, sol-gel, and slurry coatings have been identified as plausible coating techniques. An emphasis has been placed on glass and sol-gel coatings due to their previous successes in similar applications. Candidates for coatings include boro-aluminosilicates, silicon carbide, DLC, low boron glasses, aluminum oxide, and zirconium oxide. In-house methods of deposition consist of dipping, while out-of-house, commercial methods of deposition are non-line-of-sight processes, such as PECVD, due to the geometry of the fuel pellets.
Preliminary examinations of the corrosion barrier coatings include SEM-EDS and XRD. Once the initial inspection is passed, the samples are subjected to steam autoclave test to simulate leakage conditions. The samples’ integrity is then re-evaluated with SEM-EDS, XRD and mechanical testing.
Future Work
- Procurement of various metallic PVD coatings
- In-house development and optimization of PVD coatings
- Continued autoclave testing of coating materials
Our collaborators on this project are Westinghouse Electric Company and Los Alamos National Lab
