Degradation Mechanisms of Copper and Copper Alloys

As more of the world turns to nuclear energy as a source of low-carbon electricity, the demand for safe and economical nuclear materials grows. Canada has been a world leader in nuclear energy since the inception of nuclear science, and today is taking on ever more ambitious nuclear projects, including the design of small modular reactors, and the permanent disposal of nuclear waste in deep geological repositories.This document addresses the degradation methods that can affect materials used in the nuclear energy industry, both for electricity production and waste disposal. The applications and limitations of copper alloys used for nuclear energy production are discussed. This work is compiled as a paper-based thesis addressing the central theme of degradation of copper and copper alloys. As such, it is split into four individual papers, each structured in a typical journal article format. A mechanism for dealloying and intergranular attack of Monel 400, a Ni-Cu alloy used as a steam generator tubing material, is proposed. Dealloying of Monel is contingent on the accumulation of Cu2+, which stabilizes metallic copper. This is achieved in the nuclear steam generator by accumulation of corrosion products within hideout regions. The roles of steam generator impurities on the corrosion of Monel 400 are probed using electrochemical methods, and corrosion character is observed by electron microscopy and secondary ion mass spectrometry. The mechanical properties of high purity electrodeposited copper which is intended for use in the disposal of nuclear waste are evaluated. Hydrogen embrittlement was observed in electrodeposited copper. Internal hydrogen dynamics were studied using high temperature thermal desorption analysis, which provide insights into the trapping and storage of hydrogen within copper. Hydrogen embrittlement of electrodeposited copper was sensitive to both strain rate and temperature, and a mechanism of embrittlement contingent on the mobility of hydrogen is discussed.

Department dc:contributor.department

Chemical Engineering Applied Chemistry

Year dc:date.issued

2025

Author dc:creator

• Williams, Desmond Donald Cook

Advisor dc:contributor.advisor

• Newman, Roger C

• Corrosion
• Hydrogen Embrittlement
• Nuclear Materials

Handle dc:identifier.uri

https://hdl.handle.net/1807/150186

OAI identifier oai:identifier

oai:utoronto.scholaris.ca:1807/150186