Westinghouse BWR Coated Cladding Development
Year: 2026
Type: conference-paper
Abstract: The development of coated cladding for pressurized water reactors (PWR) has progressed far, but the developed Cr coatings cannot withstand the more oxidizing environment of boiling water reactors (BWR), resulting in their dissolution into the coolant. This calls for the development of new coating solutions, with compositions and microstructures specifically tailored to combat the harsher conditions while maintaining key performance-enhancing properties. Potential oxidation resistant candidate materials include the well-known and readily applied TiN and CrN, but autoclave testing has revealed them to also rapidly degrade. Westinghouse has further developed CrN - where coatings based on CrNbN have proven especially promising, with minimal oxide growth in autoclave testing at high levels of dissolved O2. Testing at high O2 levels raises the electrochemical corrosion potential (ECP) of the coated cladding, much like during the operation of a BWR, but it does not cover the effects of other oxidizing species formed through water radiolysis - particularly the relatively long-lived hydrogen peroxide, H2O2. While the resulting ECP may not differ much between a high-O2 environment and a more prototypical O2/H2O2 mixed environment, the oxidation reaction paths can qualitatively differ, resulting in more severe degradation of the coatings in the mixed environment. In the present work, analysis results from coatings exposed to various autoclave environments are compared and benchmarked against results from in-reactor testing. This comparison highlights the need for high-precision control of the testing environment to maximize the reliability and applicability of the results as a predictor of the coating performance under reactor conditions.
Language: English
Subfield: Materials Chemistry
Field: Materials Science
Domain: Physical Sciences
Open Access status: green
OpenAlex ID: W7213489332