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The following information was received by … The following information was received by facsimile from the vendor:</br>Component: Speed switch P/Ns ESl50267C, ESl50267E, ESl50267H, and ESl50267K.</br>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.</br>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.</br>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.</br>Affected nuclear plants include Nine Mile Point, Quad Cities, Dresden, Davis Besse and Hope Creek.ties, Dresden, Davis Besse and Hope Creek.
04:00:00, 25 October 2017 +
53,037 +
17:00:00, 26 October 2017 +
04:00:00, 25 October 2017 +
The following information was received by … The following information was received by facsimile from the vendor:</br>Component: Speed switch P/Ns ESl50267C, ESl50267E, ESl50267H, and ESl50267K.</br>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.</br>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.</br>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.</br>Affected nuclear plants include Nine Mile Point, Quad Cities, Dresden, Davis Besse and Hope Creek.ties, Dresden, Davis Besse and Hope Creek.
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00:00:00, 26 October 2017 +
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01:41:35, 2 March 2018 +
17:00:00, 26 October 2017 +
1.542 d (37 hours, 0.22 weeks, 0.0507 months) +
04:00:00, 25 October 2017 +
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