ENS 56347: Difference between revisions
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This 60-day optional telephone notification is being made in lieu of an LER [Licensee Event Report] submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). At approximately 0637 EST on December 25, 2022, the 2B EDG inadvertently started and ran unloaded without a valid undervoltage or safety injection actuation signal. It was determined that this condition was caused by the failure of the emergency start button due to age-related degradation. The button is normally held depressed (closed) by the glass enclosure in standby. To start the EDG using the Emergency Start Button, the button is released (open) when the glass enclosure is broken, which sends a start signal to the EDG. During troubleshooting, the resistance across the button contacts was measured at zero volts DC, indicating the button had failed to an open state causing the EDG to start. The button fell apart when the glass enclosure was removed. The actuation was not initiated in response to actual plant conditions, it was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the emergency diesel generator. | This 60-day optional telephone notification is being made in lieu of an LER [Licensee Event Report] submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to the reporting requirements specified in 10 CFR 50.73(a)(2)(iv)(A) for an invalid actuation of one of the systems listed in 10 CFR 50.73(a)(2)(iv)(B). At approximately 0637 EST on December 25, 2022, the 2B EDG inadvertently started and ran unloaded without a valid undervoltage or safety injection actuation signal. It was determined that this condition was caused by the failure of the emergency start button due to age-related degradation. The button is normally held depressed (closed) by the glass enclosure in standby. To start the EDG using the Emergency Start Button, the button is released (open) when the glass enclosure is broken, which sends a start signal to the EDG. During troubleshooting, the resistance across the button contacts was measured at zero volts DC, indicating the button had failed to an open state causing the EDG to start. The button fell apart when the glass enclosure was removed. The actuation was not initiated in response to actual plant conditions, it was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation of the emergency diesel generator. | ||
The NRC Resident Inspector has been notified. | The NRC Resident Inspector has been notified. | ||
| URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2023/ | | URL = https://www.nrc.gov/reading-rm/doc-collections/event-status/event/2023/20230213en.html#en56347 | ||
}}{{unit info | }}{{unit info | ||
| Unit = 2 | | Unit = 2 | ||
Latest revision as of 08:30, 13 February 2023
| Where | |
|---|---|
Calvert Cliffs  Maryland (NRC Region 1) | |
| Reporting | |
| 10 CFR 50.73(a)(1), Submit an LER, Invalid Actuation | |
| Time - Person (Reporting Time:+1108.05 h46.169 days <br />6.596 weeks <br />1.518 months <br />) | |
| Opened: | Ervin Lyson 15:40 Feb 9, 2023 |
| NRC Officer: | Adam Koziol |
| Last Updated: | Feb 9, 2023 |
| 56347 - NRC Website
| |