ML041320547

Deficiency Report Re Potential Safety Hazard That Exists for Woodward Digital Reference Unit (Drus)

ML041320547
Person / Time
Site:	Wolf Creek, Seabrook
Issue date:	04/23/2004
From:	Collins T Fairbanks Morse Engine
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
Download: ML041320547 (1)

Text

FAIRBANKS MORSE Q 701 White Avenue Beloit, Wisconsin 53511 Tel: 608.364.8424 Fax: 608.364.8417 Ted .stevenson@fairbanksmorse.com April 23, 2004 Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Woodward Digital Reference Unit (DRU)

On April 21, 2004, Fairbanks Morse Engine evaluation determined a potential safety hazard exists for Woodward DRU's. The FM P/N is 12998236 and the Woodward P/N is 9903-439.

The defect exhibits erratic ramp up of speed and hence the inability to reach rated RPM and inability to apply load to the engine. The cause has been traced to a random contamination problem of an integrated circuit (IC) in DRU's manufactured by Woodward between November 2000 and January 2002.

The rate of occurrence is less than 10 in the US and approx 20 worldwide. There are approx 38,000 Woodward units worldwide that use this IC. Only one US nuclear utility has experienced this failure and the failure occurred during testing prior to declaration of operability. In all cases, the failure occurs within a very few hours of operation. Therefore, if a DRU has been installed and has been operating for many hours/years, it is not at risk for this failure.

The utilities that FM has supplied DRU's to in the timeframe identified that may be affected include the following:

Utility Site Year Shipped FP&L Seabrook 2001 WCNOC Wolf Creek 2001 The above utilities are also being notified and affected DRU's will have IC's replaced as necessary.

Sincerely, Todd Collins Manager, QA an EnPro Industries company