Morning Report for March 28, 2006
Headquarters Daily Report
Part 21 2006-0004-00 - Turkey Point Auxiliary Feed Pump Drive End Journal Bearing Was Installed Incorrectly
| Licensee/Facility: |
| Notification: |
MR Number: H-2006-0006
Source Document: Letter
The Turkey Point Nuclear (TPN) Plant Auxiliary Feed Pump drive end (DE) journal bearing was installed incorrectly (radial orientation) which resulted in internal oil passage blockage and the possibility of premature bearing failure due to lack of lubrication.
The plant reported to Sulzer on 11/8/05 that the DE journal bearing in one of the repaired pumps had been installed incorrectly so that the oil passage between the housing and journal obstructed the free flow of lube oil to the bearing journal. It was postulated the premature bearing failure was due to the lack of lubrication as a direct result of improper assembly of the journal bearing. Sulzer had generated an assembly procedure based on input from an Florida Power & Light (FP&L) supplied procedure, and enhanced the assembly procedure; however, neither the FP&L nor Sulzer procedure included a verification of bearing radial orientation. Regardless, the installation of the journal bearing should have been performed properly. The improper installation of the bearing (radial orientation) was due to human error. Sulzer had repaired two other identical TPN Auxiliary Feed pumps using the same procedure, and subsequent inspections confirmed the journal bearing had been correctly installed in the other pumps Sulzer had repaired. This was an isolated case of human error coupled with a procedure that, viewed in hindsight, can be updated to include a verification of bearing orientation (barrier). Given the obvious oil passage design configuration coupled with the proper assembly of the other two pumps, this is not believed to be a generic issue.
Sulzer is not aware of the existence of a like condition. The turbine end bearing assembly is not subject to a similar assembly error due to its configuration difference. As previously mentioned Sulzer and other manufacturer's pump designs incorporate features and instructions to preclude incorrect assembly. The only other pump component where similar improper assembly is possible is ball bearing installation. In designs that incorporate duplex pairs of ball bearings the assembly instructions specify proper orientation (i.e. face-to-face or back-to-back).
The improper assembly of the subject pump resulted in the potential for premature bearing failure. However, Sulzer believes this was an isolated case involving human error for failing to detect the oil passage would be obstructed. An inspection verification (barrier) to confirm correct bearing assembly orientation would prevent future occurrences.
|Accession No ||Accession Date |
|ML060830114 ||03/21/2006 |
|Name ||Office Abbrev ||Phone No ||E-Mail |
|TABATABAI, OMID ||NRR ||(301) 415-6616 ||OTY@nrc.gov |
|WERTZ, TRENT L ||NRR ||(301) 415-1568 ||TLW4@nrc.gov |
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