Comparing CrN and TiN Coatings for Accident-Tolerant Fuels in PWR and BWR Autoclaves

Autor: Andrea Fazi, Pratik Lokhande, Denise Adorno Lopes, Krystyna Stiller, Hans-Olof Andrén, Mattias Thuvander
Jazyk: angličtina
Rok vydání: 2022
Předmět:
Zdroj: Journal of Nuclear Engineering, Vol 3, Iss 4, Pp 321-332 (2022)
Druh dokumentu: article
ISSN: 2673-4362
DOI: 10.3390/jne3040019
Popis: The development of coatings for accident-tolerant fuels (ATFs) for light water reactor (LWR) applications promises improved corrosion resistance under accident conditions and better performances during operation. CrN and TiN coatings are characterized by high wear resistance coupled with good corrosion resistance properties. They are generally used to protect materials in applications where extreme conditions are involved and represent promising candidates for ATF. Zr cladding tubes coated with 5 µm-thick CrN or TiN, exposed in an autoclave to simulated PWR chemistry and BWR chemistry, were characterized with SEM, EDS, and STEM. The investigation focused on the performance and oxidation mechanisms of the coated claddings under simulated reactor chemistry. Both coatings provided improved oxidation resistance in a simulated PWR environment, where passivating films of Cr2O3 and TiO2, less than 1 µm-thick, formed on the CrN and TiN outer surfaces, respectively. Under the more challenging BWR conditions, any formed Cr2O3 dissolved into the oxidizing water, resulting in the complete dissolution of the CrN coating. For the TiN coating, the formation of a stable TiO2 film was observed under BWR conditions, but the developed oxide film was unable to stop the flux of oxygen to the substrate, causing the oxidation of the substrate.
Databáze: Directory of Open Access Journals
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