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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 56202 | 6 September 2022 14:21:00 | 10 CFR 50.73(a)(1), Submit an LER | 60-DAY Optional Telephonic Notification of Invalid Engineered Safety Feature Actuation Signal | The following information was provided by the licensee via email: This 60-day telephonic notification is being made in lieu of a licensee event report submittal as allowed by 10 CFR 50.73(a)(1). This notification is made pursuant to 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid engineered safety feature actuation signal. On September 6, 2022, at Waterford 3, while performing a plant protection system (PPS) power supply check, technicians observed an abnormally high voltage output. When the technicians opened the PPS bay cabinet door to adjust the voltage, they then observed low voltage indications. The direct cause of this issue is believed to be vibration induced relay chattering or an intermittent connection issue when opening the rear doors of PPS cabinets. This resulted in half the logic being met for the Engineered Safety Feature Actuation Signal (ESFAS) signals to fully actuate. The ESFAS signal opened the following valves: EFW-228A (EFW to SG 1 Primary Isolation), EFW-229A (EFW to SG 1 Backup Isolation), EFW-228B (EFW to SG 2 Primary Isolation) and EFW-229B (EFW to SG 2 Backup Isolation). This was a partial actuation of ESFAS. Affected plant systems functioned successfully. The inadvertent actuation was caused by a spurious signal and was not a valid signal resulting from actual parameter inputs. The 1992 Statements of Consideration define an invalid signal to include spurious signals including jarring of a cabinet door. In accordance with 10 CFR 50.73(a)(1) a telephone notification is being made in lieu of submitting a written licensee event report. The NRC Senior Resident Inspector has been notified. These events did not result in any adverse impact to the health and safety of the public. | ||
| ENS 55281 | 2 April 2021 01:23:00 | 10 CFR 50.73(a)(1), Submit an LER | 60-Day Telephonic Notification of Invalid Plant Protection System Actuation Signal | This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid Engineered Safety Feature actuation signal. On April 1, 2021, at Waterford 3, while performing a replacement of power supplies on the Plant Protection System, a spurious signal caused a partial actuation of the Emergency Feedwater Actuation Signal. A partial Emergency Feedwater (EFW) logic trip path was met causing the opening of valves EFW-228A (EFW to SG 1 Primary Isolation), EFW-229A (EFW to SG 1 backup isolation), EFW-228B (EFW to SG 2 Primary Isolation), and EFW-229B (EFW to SG2 Backup Isolation). This inadvertent actuation was spurious and was not a valid signal resulting from parameter inputs. The 1992 Statements of Consideration (57 FR 41378) define an invalid signal to include spurious signals. Therefore, this actuation is considered invalid. This event was entered into the Waterford 3 corrective action program for resolution. This event did not result in any adverse impact to the health and safety of the public. The plant responded as expected. In accordance with 10 CFR 50.73(a)(1) a telephone notification is being made in lieu of submitting a written Licensee Event Report. The NRC Senior Resident Inspector has been notified. | Feedwater | |
| ENS 54205 | 25 June 2019 22:13:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid Engineered Safety Feature Actuation Signal Due to Human Error | This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) and 10 CFR 50.73(a)(2)(iv)(A) to provide information pertaining to an invalid Engineered Safety Feature actuation signal. On June 25, 2019, at Waterford 3, while performing an emergent replacement of relays on the Engineered Safety Features Actuation System Train A that affected Shield Building Ventilation Train A and HVAC Equipment Room Supply Fan AH-1 3A, unintentional contact was made between two contacts on the relay, resulting in an inadvertent initiation of other relays in the sequencer circuit. This caused the starting of Low Pressure Safety Injection Pump A, Switchgear Ventilation Fan A, and Boric Acid Makeup pumps. This was a partial actuation of Engineered Safety Features Actuation System Train A. Affected plant systems started and functioned successfully. This inadvertent actuation was caused by human error and was not a valid signal resulting from parameter inputs. The 1992 Statements of Consideration define an invalid signal to include human error. Therefore, this actuation is considered invalid. This event was entered into the Waterford 3 corrective action program for resolution. This event did not result in any adverse impact to the health and safety of the public. In accordance with 10 CFR 50.73(a)(1), a telephone notification is being made in lieu of submitting a written Licensee Event Report. The NRC Senior Resident Inspector has been notified. | HVAC Shield Building | |
| ENS 42860 | 7 September 2006 12:50:00 | 10 CFR 50.73(a)(1), Submit an LER | Invalid System Actuation | On September 7, 2006 at about 0750 CDST, an invalid actuation of B train Engineered Safety Features Actuation System (ESFAS) occurred during maintenance on ESFAS relay K110 B. The following B train Engineered Safety Features Actuation System (ESFAS) relays de-energized: K101, K102, K103, K108 and K109. The event is reportable per 10CFR 50.73(a)(2)(iv)(A) as a 60 day notification and is being reported to the NRC by phone within 60 days. The invalid actuations did not occur when the systems had already been properly removed from service nor after the safety function had already been completed. The 32B buss de-energized which resulted in loss of pressurizer heaters Bank B and Containment Fan Coolers B and D actuated by shifting to slow speed. There was no actual Emergency Core Cooling System (ECCS) system flows actuated. All of the affected equipment functioned as designed when the relays deenergized The NRC Senior Resident was informed of the event. | Emergency Core Cooling System |