United States Nuclear Regulatory Commission - Protecting People and the Environment

Morning Report for March 31, 2004

Headquarters Daily Report

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REGION III

Part 21 - 2004-0005-00 - Potential Slippage of Blowers on Opposed Piston Engines

Licensee/Facility:

FAIRBANKS MORSE ENGINE
FAIRBANKS MORSE ENGINE
BELOIT, Wisconsin
Dockets:

License No:
Notification:

MR Number: H-2004-0009
Date: 03/25/2004


Source Document: Fax

Reviewer: HODGE, VERNON

Discussion:

Part 21 - 2004-0005-00 - Potential Slippage of Blowers on Opposed Piston Engines

On March 25, 2004, Fairbanks Morse Engine, a vendor of emergency diesel engines, reported that the aluminum rotors of the Roots blowers (Part No. 16609294) may slip on the steel shaft and cause rotor-to-rotor or rotor-to-housing contact that could cause blower failure and inability of the engine to perform its safety function. These blowers are rotary positive-displacement devices for removing exhaust gases from each engine cylinder.

The defect is caused by an inadequate bond produced by improper cleaning of the shaft prior to casting the rotor onto the shaft. This allows the aluminum rotor to move axially on the steel shaft. Sample testing of rotors has found this condition to exist on about 75 percent of rotors produced between 1998 and 2003. Affected nuclear power plants include Limerick, Units 1 and 2, and Arkansas Nuclear One, Unit 2. To date, all slipped rotors have been found during routine maintenance inspections and no inservice engine failures have been experienced as a result of this problem.

Information for this issue as well as other Part 21s is available at the NRC's Operating Experience web page at:
http://www.nrc.gov/reading-rm/doc-collections/event-status/part21/.

Contacts:

Name Office Abbrev Phone No E-Mail
HODGE, VERNON NRR (301) 415-1861 CVH@nrc.gov
Page Last Reviewed/Updated Thursday, March 29, 2012