ENS 40699
ENS Event | |
|---|---|
05:00 Apr 21, 2004 | |
| Title | Fairbanks Morse Engine Has Determined a Potential Safety Hazard with the Woodward Digital Reference Unit (Dru) |
| Event Description | 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.
Fairbanks Morse Engine evaluation has determined a potential safety hazard exists for Woodward Digital Reference Units (DRUs). The FM P/N is 12998236, and the Woodward P/N is 9903-439. A list of specific affected S/N's is identified in the letter dated 01/12/06. 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 interaction between solder flux and integrated circuit (IC) material causing chip delamination. This condition is further described in Woodward Service Bulletin 01363, dated December 2005. This same problem had been previously reported on 4/23/04, and at that time was thought to only affect DRU's manufactured between November 2000 thru January 2002. The manufacturer thought they had purged their stock of the specific IC chips that manifested the problem, but additional chips have been found in their system that now extends the affected time period to December 2005. DRU's that have had IC chips replaced per the earlier 10 CFR 21 notification are not affected due to the use of a different solder flux that does not introduce the problem. The utility that FM has supplied DRU's to in the timeframe identified that are affected Include the following: Utility Site Detroit Edison Fermi First Energy BV-2 SCE&G VC Summer The above utilities are also being notified and affected DRU's will have IC's replaced as necessary. Notified R1DO (Conte), R2DO (Munday), R3DO (O'Brien), NRR EO (Mayfield), and emailed and faxed to Part 21 Coordinator (Tabatabai) |
| Where | |
|---|---|
| Fairbanks Morse Engine Beloit, Wisconsin (NRC Region 3) | |
| Organization: | Fairbanks Morse Engine |
| Reporting | |
| 10 CFR 21.21 | |
| Time - Person (Reporting Time:+55.68 h2.32 days <br />0.331 weeks <br />0.0763 months <br />) | |
| Opened: | Todd Collins 12:41 Apr 23, 2004 |
| NRC Officer: | Chauncey Gould |
| Last Updated: | Jan 12, 2006 |
| 40699 - NRC Website | |
Fairbanks Morse Engine with 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | |
WEEKMONTHYEARENS 465232010-11-16T06:00:00016 November 2010 06:00:00
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