Corrosion on underwater usage for SAE 660 Bronze Bushings, Need Alternatives

[AnthonyJ777]

Forum,

I need help trying to determine why the SAE 660 bronze bushings in our underwater nuclear fuel handling tool are experiencing aggressive corrosion rates. The two pictures below are just two examples of some of the types of corrosion we're seeing. From my understanding the blue color is Patina, a rust specific for bronze/copper metals. The red color looks like a traditional rust on carbon based metals. Why we're seeing two different types of rust in a span of a few months when other equipment using similar bushing material have been in the pool for years, we're currently investigating.

This may be more for the chemical engineering forum, if so, I can move.

 

[MikeHalloran]

ISTR reading that copper-bearing steels were prohibited from use in nuclear pressure vessels, because the copper severely reduced the fatigue life in the presence of radiation.

The tactic would have worked well, except that the vessels were then welded with wire that was coated with copper for corrosion protection. Meaning that the resulting welded vessels had a severely limited fatigue life.

I.e., it occurs that the copper is suffering from the radiation.
Have you evaluated the various plastic bearing materials that are available?


Mike Halloran
Corinth, NY, USA