Investigations on physical vapor deposition chromium coatings on Zircaloy-4 cladding using magnetron sputtering for accident tolerant fuel applications

During the operation of nuclear power plants, safety is of paramount importance. It is important to implement engineering barriers to help reduce risk in the event of an accident, such as in the Fukushima nuclear accident. To this end, the development of accident tolerant fuels is an important task. While numerous types of accident tolerant fuels are being developed, a near term solution is to create chromium coatings on Zircaloy claddings to help increase their oxidation resistance. In this work, chromium was physical vapor deposited onto a Framatome Zircaloy-4 cladding utilizing a custom magnetron sputtering chamber with three sputtering guns. The number of guns, power of each gun, and sputtering time was varied in an attempt to generate a coating that was uniform within 10% of the average thickness over a span of 4.25 inches. During the experiment, seven batches of cladding were coated. Before coating, the samples were cut into smaller segments and weighed, as to provide a means to determine the mass gained during the sputtering process. The thickness of the coating deposited on each sample was calculated and plotted against the distance from the center of the sputtering chamber, and the uniformity of the coating was evaluated. In most batches, the coating was uniform across the full desired length. The adhesion of the coating was investigated to determine if the chromium was successfully sputtered onto the cladding samples. Despite technical issues with the sputtering guns, the adhesion was found to be mostly acceptable. Finally, characterization was performed on the samples. Select samples were investigated with x-ray diffractometry, verifying the coating was BCC chromium. Another sample was characterized by scanning electron microscopy to observe the columnar grains deposited. During the x-ray diffractometry, it was found that the chromium peaks and zirconium peaks could be seen on the samples with thinner coatings. However, the zirconium peaks had a degree of overlap with the chromium peaks, making drawing conclusions difficult. On the samples with thicker coatings, the zirconium peaks dropped away to reveal well aligned chromium peaks only, evidencing a grown layer of textured BCC chromium.

Name thesis:degree_name

M.S.

Level thesis:degree_level

Thesis

Discipline thesis:degree_discipline

Nuclear, Plasma, Radiolgc Engr

Grantor

University of Illinois at Urbana-Champaign

Year dc:date

2024

Author dc:creator

• Evans, Anthony

Contributors dc:contributor

• Heuser, Brent J
• Vergari, Lorenzo

• Chromium Coatings
• Magnetron Sputtering
• Physical Vapor Deposition
• Accident Tolerant Fuels

Statement dc:rights

• Copyright 2024 Anthony Evans

Language dc:language

en, eng

Handle dc:identifier

https://hdl.handle.net/2142/127300

OAI record oai:identifier

https://www.ideals.illinois.edu/oai-pmh?verb=GetRecord&metadataPrefix=etdms&identifier=oai%3Awww.ideals.illinois.edu%3A2142%2F127300