Experimental evaluation of cold spray FeCrAl alloys coated zirconium-alloy for potential accident tolerant fuel cladding

Journal Article · 01 December 2019 · Nuclear Materials and Energy

DOI: https://doi.org/10.1016/j.nme.2019.100715 · OSTI ID:1575317

Dabney, Tyler  ^[1]; Johnson, Greg ^[1]; Yeom, Hwasung ^[2]; Maier, Ben ^[1]; Walters, Jorie ^[1]; Sridharan, Kumar ^[3]

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1. Univ. of Wisconsin, Madison, WI (United States). Dept. of Material Science and Engineering
2. Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics
3. Univ. of Wisconsin, Madison, WI (United States). Dept. of Material Science and Engineering; Univ. of Wisconsin, Madison, WI (United States). Dept. of Engineering Physics

Two FeCrAl alloy coatings with different Cr and Al contents were deposited on Zr-alloy substrates via the cold spray deposition method to study the efficacy of these coatings to improve the accident tolerance of Zr-alloy fuel cladding in light water reactors (LWRs). First, the coatings were tested in a 400 °C steam autoclave for 72 h as an accelerated method to simulate the normal LWR operating conditions. In these tests, both coatings resulted in notable improvements in oxidation resistance compared to the Zr-alloy, with the higher Cr containing coating exhibiting a thinner oxide layer. Both coatings provided good oxidation resistance when tested in 1200 °C ambient air environment; however, the formation of a low melting point eutectic (~928 °C) between Fe and Zr resulted in significant melting associated with inter-diffusion between Fe in the coating and the Zr in the substrate. Therefore, to take advantage of the superior oxidation resistance that FeCrAl coatings can provide, a Mo interlayer was deposited, also by the cold spray process, in-between the protective FeCrAl coating and the Zr-alloy substrate, thus creating a dual cold spray layer accident tolerant coated cladding concept. The wear resistance of the FeCrAl coating was superior to the Zr-alloy substrate based on pin-on-disk wear tests, providing an indication of the benefits of such coatings to reduce grit-to-rod fretting (GTRF) damage. The feedstock powders, microstructure, phases, hardness of coatings, as well as oxide and inter-diffusion layers of oxidized coatings were examined using SEM, XRD, and XPS characterization techniques.

• Research Organization: Westinghouse Electric Company LLC, Cranberry Township, PA (United States); Massachusetts Inst. of Technology (MIT), Cambridge, MA (United States)
• Sponsoring Organization: USDOE Office of Nuclear Energy (NE)
• Grant/Contract Number: NE0008222; NE0008416
• OSTI ID: 1575317
• Alternate ID(s): OSTI ID: 1801186
• Journal Information: Nuclear Materials and Energy, Vol. 21, Issue C; ISSN 2352-1791
• Publisher: ElsevierCopyright Statement
• Country of Publication: United States
• Language: English