ENS 53037
ENS Event | |
|---|---|
04:00 Oct 25, 2017 | |
| Title | Part 21 - Speed Switch Issue Results in Emergency Diesel Generator Failure to Start |
| Event Description | The following information was received by facsimile from the vendor:
Component: Speed switch P/Ns ESl50267C, ESl50267E, ESl50267H, and ESl50267K. Summary: Engine Systems Inc. (ESI) began a 10CFR21 evaluation on September 12, 2017 upon notification of a potential issue with speed switch P/N ESl50267K supplied to Hope Creek Nuclear Generating Station. The speed switch had reportedly failed in service which resulted in a failure to start of the emergency diesel generator (EDG). An analysis performed by Exelon Powerlabs determined the failure was due to a shorted capacitor that is installed on the speed switch's relay output contacts to ground. The evaluation was concluded on October 25, 2017 and it was determined that this issue is a reportable defect as defined by 10CFR Part 21. The speed switch output contacts are utilized in the engine's start circuitry and failure to function properly could adversely affect the safety-related operation of the emergency diesel generator set. Impact on Operability: If the resistance path to ground were sufficiently low, the ability of the relay output contacts to pick-up and/or drop-out associated components would be compromised. The speed switch relays are used in safety-related EDG start circuitry to control various electrical relays. Failure to properly control any of these components could adversely affect the safety-related operation of the emergency diesel generator. Root cause evaluation: The root cause of the failure is a deficiency in the design and selection of the EMC (Electromagnetic compatibility) mitigating components. Consideration was not given for the impact of voltage transients imparted on the capacitors during coil de-energization. For customers without suppression from the inductive kick, the magnitude of voltage transients may be sufficient to damage and ultimately degrade the capacitors to the point of failure. Affected nuclear plants include Nine Mile Point, Quad Cities, Dresden, Davis Besse and Hope Creek. |
| Where | |
|---|---|
| Engine Systems, Inc. Rocky Mount, North Carolina (NRC Region 1) | |
| Organization: | Engine Systems, Inc |
| Reporting | |
| 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
| Time - Person (Reporting Time:+37 h1.542 days <br />0.22 weeks <br />0.0507 months <br />) | |
| Opened: | Tom Horner 17:00 Oct 26, 2017 |
| NRC Officer: | Vince Klco |
| Last Updated: | Oct 26, 2017 |
| 53037 - NRC Website | |
Engine Systems, Inc. with 10 CFR 21.21(d)(3)(i), Failure to Comply or Defect | |
WEEKMONTHYEARENS 569132023-11-27T05:00:00027 November 2023 05:00:00
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