Browsing the NRC Event Reports page this morning, I found an item about refurbished parts for emergency diesel generators.
Engine Systems, Inc. (ESI) in Rocky Mount, North Carlina, issued a final report on a problem encountered at the Perry nuclear power plant in Ohio. Perry had ordered four refurbished piston assemblies for its emergency diesel generators. After the assemblies were installed, operators discovered that “large portions of the tin plating were flaking or smearing off.” (Bear with me. I know that Nuclearese can be an effective sleep aid.)
ESI determined that the “delamination was attributed to residual oil impregnated in the ductile cast iron base material of the skirts.”
The company also said that “ESI is not aware of any absolute methods for ensuring all oils have been removed (or at least to the point that it will not interfere with tin plating adhesion.)” Therefore, “it is ESI’s recommendation that piston skirts which have been in service should no longer be re-tin plated.”
A large focus of this blog is to ask the obvious questions in cases like this:
1. How many reactors use refurbished pistons supplied by ESI?
2. Is there any likely damage to diesel generators that have tin flaking off inside the mechanism?
3. ESI said in the Event Report that the company had found the piston delamination “to be a reportable defect as defined by 10CFR21.” Does that mean that ESI is recommending that defective parts continue to be used in violation of the Code of Federal Regulations section cited?
4. Are there other companies that can provide the refurbised pistons and guarantee that they won’t fall apart inside the generators?
5. What is the Nuclear Regulatory Commission going to do about this issue? Could they require that new piston assemblies be used in the generators rather than refurbished ones?