Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 46523 | 16 November 2010 06:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Part 21 Report for Potential Safety Hazard on Speed Switch Installed on Emergency Diesel Generator (Edg) | The following was received via fax: (Fairbanks Morse (FM) determined) that when the speed switch assembly was mounted on a conductive surface, the voltage regulator grounded out the 24 volt direct current power through the heat sink preventing the speed switch from operating. This condition was not detected prior to the first speed switch being shipped to Hope Creek in September, 2010. It was never installed on the EDG prior to being recalled. The unit was returned to FM and has since been reworked and verified to be in compliance with the latest design to eliminate the deficiency. | Emergency Diesel Generator | |
| ENS 40699 | 21 April 2004 05:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Fairbanks Morse Engine Has Determined a Potential Safety Hazard with the 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.
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) | ||
| ENS 40610 | 25 March 2004 06:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Part 21 Notification Involving Potential Safety Hazard for Blowers on Op Engines | Subject:Roots Blower on OP Engines On March 23, 2004, Fairbanks Morse Engine evaluation determined a potential safety hazard exists for blowers (P/N 16609294) on OP engines. It is possible that the aluminum rotors can slip on the steel shaft and cause rotor-to-rotor or rotor-to-housing contact which could cause blower failure and inability of engine to perform its safety function. The defect was caused by improper cleaning of the shaft prior to casting the rotor onto the shaft. This causes an inadequate bond and allows the aluminum rotor to move axially on the steel shaft. Sample testing of rotors has found this condition to exist to varying degrees on approximately 75% of rotors produced between 1998 and 2003. (4) blowers were shipped to nuclear utilities that may be affected: Utility Site Blower S/N Exelon Limerick (RB813A, RB3871, RB816) Entergy ANO-2 (RB814) To date, no engine failures have been experienced as a result of this problem. However, the potential exists. All slipped rotors have been found during routine maintenance inspections. This condition has been found to manifest itself within a low number of hours of operation. Therefore, the longer the rotors run and maintain proper clearance, the less likely they are to be affected by this condition. The affected utilities will be notified to evaluate inspection results and replace as necessary. | ||
| ENS 40524 | 16 February 2004 06:00:00 | 10 CFR 21.21, Notification of failure to comply or existence of a defect and its evaluation | Part 21.21 Notification of Potential Safety Hazard Associated with Use of Turbocharger | On February 12, 2004, Fairbanks Morse Engine evaluation determined a potential safety hazard associated with the use of ABB turbocharger model VTC-304 on OP engines only. Torsional resonance has been found in the rotating assembly which is excited by exhaust pulses. The resonance manifests itself as either a bent or broken shaft, slipped compressor wheel, cracked compressor wheel or complete rupture of the compressor set. Once failure occurs, engine power cannot be sustained. This condition is corrected by machining the rotating assembly to tune the natural frequency away from operating conditions. The only affected site is Crystal River 3. (6) turbos have been shipped to this site. None of the turbos have been installed and all are in storage. The FM parts department will arrange to have the turbos returned to the factory to have the necessary machining performed. |