Abstract
Accident tolerant fuel claddings seek to improve safety margins during loss-of-coolant accident (LOCA) scenarios by reducing cladding steam oxidation rates, hydrogen production, delaying or mitigating cladding burst, and reducing cladding deformation. After rapid and extensive progress in recent years, Cr coated Zr-based alloys, ferritic FeCrAl, and SiC/SiC ceramic matrix composites (CMCs) have emerged as the most promising cladding concepts, but there are few studies comparing the accident tolerance of all three concepts simultaneously. In this study, LOCA burst testing has been conducted on Cr high impulse power magnetron sputtered Zry-4 (Cr/Zry-4), C26M (FeCrAl), and SiC/SiC SiGA (CMC). Experimental observations indicate Cr/Zry-4 burst at higher temperatures than Zry-4 however the effectiveness of the coating on mitigating ZrO2 formation via Cr2O3 formation depended on physical proximity to the burst opening. No dramatic improvement in diametrical strain nor opening geometry was observed. C26M burst at higher temperatures than Zry-4 at lower pressures, exhibiting small amounts of strain and smaller openings, and formed slow-growing Al2O3 regardless of location. The CMCs did not burst or show any macroscopic signs of deformation, all the way up to an internal cladding pressure of 15.2 MPa. High temperature expanding Nb plug testing indicated that CMC room temperature strength may persist up to 1650°C, with an approximately 40% loss of strength at 1900°C. CMC steam oxidation was also compared to reference chemically vapor deposited SiC up to 1700°C, and CMCs were found to oxidize at slightly accelerated rates that were still orders of magnitude lower than bare Zry-4. Projected H2 generation during LOCA burst testing showed that when accounting for cladding burst exposing inner diameters to steam, Cr coated Zry-4 reduced H2 generation by a factor of two compared with bare Zry-4, while both C26M and SiC/SiC reduced H2 generation by orders of magnitude relative to bare Zry-4.
| Original language | English |
|---|---|
| Article number | 154152 |
| Journal | Journal of Nuclear Materials |
| Volume | 574 |
| DOIs | |
| State | Published - Feb 2023 |
Funding
The authors would like to acknowledge A. Nelson and K. Linton for programmatic support, B. Johnston, M. Howell, and A. Willoughby for technical assistance, T. Geer, C. O'dell, and V. Cox for metallography, and M. Ridley for technical manuscript review. This study was supported by the US Department Energy (DOE), Office of Nuclear Energy, for the Advanced Fuels Campaign of the Nuclear Technology R&D program and the Westinghouse Electric Corporation/General Atomics FOA program under contact DE-AC05-00OR22725 with ORNL, managed by UT Battelle, LLC. This manuscript has been authored by UT-Battelle, LLC under Contract No. DE-AC05-00OR22725 with the U.S. Department of Energy. The United States Government retains and the publisher, by accepting the article for publication, acknowledges that the United States Government retains a non-exclusive, paid-up, irrevocable, world-wide license to publish or reproduce the published form of this manuscript, or allow others to do so, for United States Government purposes. The Department of Energy will provide public access to these results of federally sponsored research in accordance with the DOE Public Access Plan (http://energy.gov/downloads/doe-public-access-plan).
| Funders | Funder number |
|---|---|
| V. Cox for metallography | |
| Westinghouse Electric Corporation/General Atomics | DE-AC05-00OR22725 |
| U.S. Department of Energy | |
| Office of Nuclear Energy | |
| Oak Ridge National Laboratory | |
| UT-Battelle |
Keywords
- Accident tolerant fuel cladding
- Burst testing
- Ceramic matrix
- Composite
- LOCA
- Steam oxidation
