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Fatigue Behavior of Cold Spray-Coated Accident Tolerant Cladding

This paper investigates the fatigue behaviour of cold spray coated Zircaloy cladding, a major advancement in Accident Tolerant Fuel (ATF) cladding for nuclear reactors. By examining the durability of coatings such as FeCrAl, Cr and Mo under normal and extreme conditions, the study highlights the importance of coating integrity in enhancing the safety and operational reliability of nuclear fuel cladding.


Type of Work: Conference Publication

Main Author: Martin Sevecek

Affiliation: MIT

Co-Authors: Mohamed Shahin, Jakub Krejci, Jan Petrik, Ronald G. Ballinger, Koroush Shirvan

Date: 2018

Conference: TopFuel 2018

Online: Research Gate

The study uses a comprehensive experimental set-up to evaluate the fatigue behaviour of Zircaloy-4, a standard substrate, coated with FeCrAl, Cr and Mo using cold spray techniques. Samples were fatigue tested in both air at room temperature and in normal water conditions (NWC), simulating reactor operating environments. This dual-environment approach provided a nuanced understanding of the performance of the coatings under different conditions. Unique to this research was the use of an experimental system designed to ASTM standards for fatigue testing, incorporating a dynamic autoclave for high temperature, high pressure scenarios, and using the Direct Current Potential Drop (DCPD) method for accurate crack growth measurement.
The results show that coated specimens exhibited early crack initiation compared to uncoated Zircaloy-4, with variations in behaviour between different coatings and test environments. For example, FeCrAl coatings showed improved fatigue life in air, whereas Cr coatings showed susceptibility to early cracking under NWC conditions. These differences in performance highlight the complex interplay between coating materials, substrate properties and environmental conditions. The results of the study caution against a one-size-fits-all approach to ATF cladding and underscore the need for tailored coating strategies to optimise cladding performance.