On February 9th, 2018, the copper rods from the Deer Island Round D testing were visually analyzed. Pictures of each side of the copper rod and relevant unique corrosion features were taken. The colors of corrosion, degree of corrosion, and specific characteristics were recorded in notes below. The corrosion classification was not done by any standardized method.

Interesting preliminary findings are that Day 3 was the most corroded, but its field duplicate did not reflect the same degree of corrosion. Days 4 and 5 were all far less corroded than Days 2 and 3. Possible reasons behind this are that the sanding process may not have been fully complete thus not removing the anti-corrosion layer completely. Other features of the corrosion are noted throughout this note.

Hopeful next steps include analyzing these rods using the scanning electron microscope (SEM) and energy dispersive x-ray spectrometer (EDS) to analyze the corrosion layers. The SEM will show what the corrosion layers look like at microscopic levels and may answer some of the issues noted above. EDS will be used to characterize the specific corrosion products found on these rods.

Considerations for next time will be to standardize the copper rod preparation process, particularly the sanding process. There seems to be differences between the samples, which are likely due to uneven sanding. Another consideration is to move away from the copper rod method and moving towards a copper sheet method for reasons that are explained in this research note. A method has been developed here and is currently being used for testing.

Color of corrosion corresponds to suspected corrosion compounds. Lionel Milberger explained these suspected compounds in his TEST Magazine article. Below is a list of color and suspected compounds based on his findings.

Corrosion Color Guide

Red-reddish colors = copper oxides

Dark blue, dark purple, black= copper-sulfur compounds

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Day 1

Colors: Copper, Black

Degree of Corrosion: Mild

Characteristics:

• The corrosion has formed only on one side (note the side with the string overlying the copper pipe), the other side is clear.
• The corrosion spread as if a viscous liquid was dropped on top and oozed down the sides to create a wavy line of corrosion.

Day 2

Colors: Copper, black, steely grey, magenta reddish, gold, purple, light blue and green

Degree of Corrosion: Medium

Characteristics:

• The corrosion is far more pronounced than Day 1
• There is still the wavy line of corrosion that is similar to Day 1
• The green to purple has somewhat of a rainbow effect, sort of like the reflection of oil in a puddle of water in a parking lot.
• There is also small spots of no corrosion surrounded by grey corrosion. Please reference the bottom image above.

Day 3

Colors: Copper, steely grey, purple, light blue

Degree of Corrosion: Medium

Characteristics:

• Similar degree of corrosion to Day 2
• Less colorful than Day 2, but more colorful than Day 1
• Less wavy and more spiky line of corrosion
• There are darker borders of corrosion along the uncorroded/corroded interface. Please reference the bottom image above.

Day 3 Field Duplicate

Colors: Copper, steely grey, purple

Degree of Corrosion: Mild

Characteristics:

• Less corrosion and not as many colors than the other Day 3 copper rod
• Shares the similar dark border along the corrosion and uncorroded interface
• There is a spot on this rod that completely resisted corrosion. It seems that the spot is an area that wasn't sanded, so the corrosive layer on the pipe was not removed. Please reference the bottom image above.

Day 4

Colors: Copper, steely grey, dark orange, red

Degree of Corrosion: Mild

Characteristics:

• Much less corrosion than either Day 3 copper rods. This could be because the anti-corrosive layer was not fully sanded off.
• There is uneven corrosion on this pipe, which supports the issue of incomplete sanding. Please reference the bottom image above.
• The corrosion of this rod doesn't have the same characteristics of the others with the seemingly liquid effect.
• Not as much of a dark border on the corrosion/uncorroded interface

Day 5

Colors: Copper, steely grey, light blue, and purple

Degree of Corrosion: Mild

Characteristics:

• There is similarly less corrosion as Day 1-3 but more colors than Day 4.
• The corrosion is still uneven.
• There are darker borders of corrosion on the corrosion/uncorroded interface.
• There is this interesting double border corrosion on the copper pipe. Please reference the bottom image above.

Day 6

Colors: Copper, steely grey, and purple

Degree of Corrosion: Mild

Characteristics:

• Similar corrosion and coloring to Day 5 without any blue
• The corrosion is still uneven
• Not very much pronounced dark borders along the corrosion/uncorroded interface
• There is lettering on this copper rod. It doesn't seem to affect the corrosion at all, but is something to note. Please reference in the bottom image above.

Control Room Away From CC

Color: Copper

Degree of Corrosion: None

Characteristics:

• No corrosion whatsoever

Control Room Near CC

Colors: Copper

Degree of Corrosion: None

Characteristics:

• No corrosion except for a few dots. They do not seem to be caused by similar conditions that the test rods were exposed to. Please refer to the third image.
• Tape was on the copper rod. Please refer to the top image above.

Side-by-side comparison