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The following information was provided by the licensee via phone and email: On November 10, 2024, at 0337 CST, Grand Gulf Nuclear Station (GGNS) was operating in mode 1 at 100 percent power when a manual scram was initiated due to degrading main condenser vacuum. The cause of the degrading main condenser vacuum is not known at this time and is being investigated. All control rods fully inserted and there were no complications. Reactor pressure was initially maintained with main turbine bypass valves. Reactor water level was initially maintained with main feedwater and condensate. At 0457, operators transitioned pressure control to safety relief valves and began using reactor core isolation cooling (RCIC) to maintain reactor water level. This was performed using plant procedures due to degrading vacuum. GGNS is currently in mode 3. Reactor level is being maintained with RCIC and pressure is being maintained using the safety relief valves. The manual reactor protection system (RPS) actuation is being reported in accordance with 10 CFR 50.72(b)(2)(iv)(B) and the RCIC actuation is being reported in accordance with 10 CFR 50.72(b)(3)(iv)(A). The NRC Senior Resident Inspector was notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At the time of the notification, main steam isolation valves had shut on low vacuum.

• * * UPDATE ON 11/10/24 AT 1236 CST FROM MELISSA LIMBECK TO KERBY SCALES * * *

The following update was provided by the licensee via phone and email: This update is being made to report the following occurrences which took place after the scram reported in event number 57418. On November 10, 2024, at 0545 CST, a group 1 containment isolation signal resulted in the closure of all MSIVs. The signal was due to continued degradation of condenser vacuum post-trip. At 0620, an automatic RPS actuation occurred when reactor water level lowered to level 3. This RPS actuation occurred with all control rods fully inserted. Reactor water level lowered following closure of an open safety relief valve and was recovered to within the established band. The events are being reported as specified system actuations in accordance with 10 CFR 50.72(b)(3)(iv)(A). The NRC Senior Resident Inspector has been informed of the update. Notified R4DO (Dixon)

The following information was provided by the licensee via phone and email: At 1822 CST on September 27, 2024, Grand Gulf Nuclear Station (GGNS) was conducting surveillance testing on the high pressure core spray (HPCS) division Ill diesel generator. Following initiation of the test signal, the HPCS pump room cooler start time exceeded the surveillance procedure allowance of less than or equal to 20 seconds. The HPCS pump room cooler started in 26.2 seconds. HPCS was already inoperable for performance of the surveillance testing. The event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition which could have prevented the fulfillment of a safety function. Troubleshooting is in progress. HPCS, a single-train system, will remain inoperable until the condition is corrected. All sources of offsite power are available. No other safety systems are inoperable. Reactor core isolation cooling was verified to be operable per GGNS technical specification 3.5.1.B.1. The NRC Senior Resident Inspector has been notified.

• * * RETRACTION ON 11/25/2024 AT 1333 EST FROM JEFF HARDY TO IAN HOWARD * * *

Investigation of the delayed start time of the HPCS pump room cooler indicated that the condition would not have challenged the ability of the room cooler to maintain temperatures less than the temperature limit of 150 degrees Fahrenheit. As a result, HPCS remained capable of fulfilling its safety function. Therefore, EN 57349 is being retracted. The NRC senior resident inspector has been notified of this retraction. Notified R4DO (O'Keefe)

The following information was provided by the licensee via email: At 0146 CDT on June 7, 2024, River Bend Station (RBS) was operating at 100 percent power when a loss of control room envelope (CRE) was declared due to failing to meet Technical Specification (TS) 3.7.2, Surveillance Requirement (SR) 3.7.2.4, during surveillance testing. Mitigating actions were established which included the ability to issue potassium iodide to control room staff. With mitigating actions in place, the dose consequence to control room staff continued to be less than the regulatory limit of 5 rem total effective dose equivalent for the duration of a design basis event. The CRE is considered a single train system at RBS, therefore, this event is being reported in accordance with 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function. The NRC resident inspector has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The failed surveillance (SR 3.7.2.4) was for unfiltered air in-leakage greater than 300 cubic feet per minute.

• * * RETRACTION ON 08/05/2024 AT 1456 EDT FROM DARREN FARTHING TO ROBERT THOMPSON * * *

This event was initially reported under 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented the fulfillment of a safety function. The licensee determined in a subsequent engineering evaluation of the conditions that existed at the time, that there was no adverse impact on the control room emergency ventilation system or the control room envelope (CRE) boundary's ability to perform its safety function. The CRE would not have been challenged to meet the regulatory limit of 5 rem total effective dose equivalent for the duration of a design basis event. Consequently, this condition is not reportable as an event or condition that could have prevented the fulfillment of a safety function. The NRC resident inspector has been notified. Notified R4DO (Vossmar).

The following information was provided by the licensee via email: At 1545 CST on November 10, 2023, personnel at Waterford Steam Electric Station Unit 3 determined that 19 conduits in the engineered safety features actuation system (ESFAS) auxiliary relay cabinets A and B did not have the required fire seals for bay separation. This condition meets the criteria involving an unanalyzed condition that significantly affects plant safety. The plant is currently defueled. Decay heat is being removed by normal spent fuel cooling system operations. ESFAS is not required to be operable in the current plant mode. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety. There was no impact to the health and safety of the public or plant personnel. The NRC Region 4 Branch Chief (Dixon) has been notified.

• * * RETRACTION ON 1/8/2024 AT 1222 EST FROM PETER RAMON TO ERNEST WEST * * *

On November 10, 2023, Waterford Steam Electric Station Unit 3 reported in EN 56849 that 19 conduits in engineered safety features actuation system (ESFAS) auxiliary relay cabinets A and B did not have the required fire seals for bay separation. This condition met the criteria involving an unanalyzed condition that significantly affects plant safety. Waterford 3 has determined that the ESFAS auxiliary relay cabinets A and B jumper conduits do not require fire seals based on review of an engineering specification that specifies the size and length of conduits which require fire seals to be installed. None of the nineteen affected conduits meet the size and length criteria that would necessitate installation of a fire seal. Based on this, the condition described in EN 56849 is not considered to be an unanalyzed condition that significantly affects plant safety as described in 10 CFR 50.72(b)(3)(ii)(B) and therefore is not reportable. The licensee notified the NRC Resident Inspector. Notified R4DO (Gaddy)

The following information was provided by the licensee via phone call and email: On October 31, 2023, at 0800 CDT, River Bend Station discovered that the results of a blind performance sample provided to an Health and Human Services (HHS)-certified testing facility were inaccurate (false negative). This report is being made in accordance with 10 CFR 26.719(c)(3). The HHS-certified testing facility has been informed of the error. The licensee notified the NRC resident inspector.

• * * RETRACTION AT 0946 EDT ON NOVEMBER 2, 2023 FROM MICAH NAVARRO TO SAMUEL COLVARD * * *

On November 1, 2023, River Bend Station personnel were informed by the HHS-certified testing facility that the cut-off levels used for analysis of the performance testing sample in question were the correct (higher) cut-off levels currently being used by the licensee. This resulted in a correct negative test. The performance testing sample sent to the HHS-certified testing facility was purchased for use based on the new lower cut-off levels in accordance with the new fit for duty (FFD) rule being implemented by the licensee on November 6, 2023. Because the higher confirmatory cut-off levels were used at the HHS-certified testing facility, the results provided were correct. The NRC Resident Inspector has been notified." Notified R1DO (Eve) and FFD Group (email)

The following information was provided by the licensee via fax: At time 0207 CDT, Cooper Nuclear Station (CNS) entered Technical Specification (Limiting Condition for Operation) LCO 3.0.3 due to declaring core spray subsystems A and B inoperable. This declaration was based on an issue with relays installed from the same manufacturing batch. The ability of the relays to function correctly to annunciate loss of logic power was called into question and they were declared inoperable. The plant has initiated actions to repair/replace affected relays. This event is reportable under 10 CFR 50.72(b)(2)(i) as an initiation of any nuclear plant shutdown required by Technical Specifications. In addition, this event Is reportable under 10 CFR 50.72(b)(3)(v) as a condition that could have prevented the fulfillment of a safety function for the core spray systems. NRC Resident Inspector was notified.

• * * UPDATE ON 5/8/2023 AT 1335 EDT FROM ANDREW ASKINS TO BRIAN LIN * * *

The following information was provided by the licensee via email: Technical Specification LCO 3.0.3 was exited at 0805 CDT on May 8, 2023. A reasonable expectation of operability was developed for the core spray subsystems A and B. There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified. Shutdown was initiated and power was reduced approximately 45 percent. Reactor power is currently at 55 percent at the time of notification. Notified R4DO (Werner) via email.

• * * UPDATE ON 5/9/2023 AT 1441 EDT FROM ANDREW ASKINS TO DONALD NORWOOD * * *

The following information was provided by the licensee via email: CNS is retracting the 8-hour 10 CFR 50.72(b)(3)(v) non-emergency notification, for a condition that could have prevented the fulfillment of a safety function, made on May 8, 2023, at 0207 CDT (EN# 56509). Subsequent evaluation concluded that the core spray subsystems remained operable in accordance with the Technical Specifications Requirements 3.5.1, ECCS - Operating. As a result of the core spray system remaining operable, no loss of safety function occurred. The NRC Senior Resident Inspector has been notified. Notified R4DO (Werner).

The following information was provided by the licensee via email: At approximately 1500 (EDT) on 5/2/2023, it was determined that the commercial telecommunications capacity was lost to the Palisades Nuclear Plant (PNP) control room and technical support center due to an issue with the telecommunications provider. After discovery of the condition it was discovered that this loss also included the emergency notification system (ENS). Communications link via the satellite phone was tested satisfactorly. In addition, if needed, the satellite phone would be used to initiate call-out of the emergency response organization. The condition did not affect the ENS or commercial telecommunications capabilities at the offsite Emergency Operations Facility. The telecommunications provider has not provided an estimated repair time. PNP will be notifying the NRC resident inspector.

• * * RETRACTION ON 06/22/23 AT 1358 EDT FROM J. LEWIS TO T. HERRITY * * *

The following information was provided by the licensee via email: This notification is being made to retract event EN 56501 that was reported on May 02, 2023. Based on further investigation, the Emergency Plan and Emergency Implementing Procedures provide an acceptable alternative routine communication system, which is satellite phones, for communicating with Federal, State, and local offsite agencies, that are in addition to the primary commercial telephone system. It was determined that no actual or potential loss of offsite communications capability existed per 10 CFR 50.72(b)(3)(xiii). This is consistent with NUREG 1022, Revision 3, Supplement 1, 'Event Report Guidelines 10 CFR 50.72(b)(3)(xiii),' and NEI 13-01, Revision 0, 'Reportable Action Levels for Loss of Emergency Preparedness Capabilities.' The NRC Decommissioning Inspector has been notified of the retraction. Commercial telecommunications to the plant were restored at approximately 0600 EDT on 5/3/2023. Notified R3DO (Orlikowski)

A non-licensed contract supervisor was confirmed to have violated the FFD policy by attempting to subvert the testing process. The individual's authorization for site access was immediately terminated. The licensee notified the R4 Branch Chief (Josey)

• * * RETRACTION FROM TITUS FOLDS TO JOHN RUSSELL AT 1606 EDT ON 05/03/2023 * * *

The following information was provided by the licensee via email: The Medical Review Officer (MRO) was provided with additional information on the collection process in question. Based on this additional information, the MRO was unable to conclude with a high degree of certainty that an attempt to subvert the FFD collection process had occurred." Notified R4DO (Gaddy) and via email the FFD Group.