Event Notification Report for September 27, 2024

EN Revision Imported Date: 11/26/2024

EN Revision Text: HIGH PRESSURE CORE SPRAY INJECTION INOPERABLE

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)

ALERT - FLOODING ONSITE

The following information is a summary of information provided by the licensee via phone:

At 1507 EDT on 9/27/2024, Nuclear Fuel Services (NFS) Erwin declared an Alert due to flooding onsite in the protected area due to Tropical Storm Helene. The Headquarters Operations Officer was notified of the Alert at 1518 EDT. All operations have been suspended and all non-essential employees have been sent home. Essential personnel are staging sandbags around vital areas to protect material storage areas. There was no release in progress and water has begun to recede. Plant personnel are conducting walkdowns of the site.

State and local authorities have been notified.

Notified DHS SWO, FEMA Ops Center, USDA Ops Center, HHS Ops Center, DOE Ops Center, CISA Central Watch Officer, EPA EOC, FDA EOC (email), FEMA NWC (email), DHS Nuclear SSA (email), DHS NRCC (email), FEMA NRCC SASC (email), FERC (email)

* * * UPDATE ON 9/27/2024 AT 2030 EDT FROM JORDAN LLOYD TO ERNEST WEST * * *

At 2020 EDT on 9/27/2024, NFS Erwin terminated the declared Alert due to water receding from the protected area. Vital areas are unimpacted; No water entered into any vital areas.

Notified DHS SWO, FEMA Ops Center, USDA Ops Center, HHS Ops Center, DOE Ops Center, CISA Central Watch Officer, EPA EOC, FDA EOC (email), FEMA NWC (email), DHS Nuclear SSA (email), DHS NRCC (email), FEMA NRCC SASC (email), FERC (email), R2DO (Suber), NMSS (Helton), IRMOC (Grant).

AGREEMENT STATE - COURIER VEHICLE ACCIDENT

The following information was provided by the Texas Department of State Health Services (the Department) via email:

"The Department was notified at 0815 [CDT] on September 27, 2024, by the licensee, that one of their courier vehicles had been involved in a vehicle accident on I-35 North, between Denton and Valley View, Texas. The accident resulted in the death of a driver of an 18 wheeler but was not related to the presence of radioactive material (RAM). The courier driver was injured with a broken leg and was transported to the hospital with non-life threatening injuries. The roadway was shut down for several hours due to diesel fuel, oil, and debris from the collision. There was no radiological involvement as part of the closure. The shipment was six `ammo' boxes containing 10 doses of F-18. Five of the containers were located in the courier vehicle and transported to a nearby hospital. The packages were surveyed on arrival at the hospital by hospital staff and placed in a secure area to await the licensee's personnel. The five packages were subsequently retrieved by the licensee. The sixth package was ejected from the transport vehicle and was not transported to the hospital with the other five packages. The licensee retrieved and surveyed [the sixth] package at the accident scene. There was no contamination or release of RAM. The investigation [by the Department] continues."

Texas Incident Number: TBD

MANUAL REACTOR TRIP ON LOWERING CONDENSER VACUUM

The following information was provided by the licensee via phone:

"At 0346 EDT on 9/27/24, with Unit 1 in mode 1 at 54 percent power, the reactor was manually tripped due to degrading condenser vacuum secondary to environmental conditions. The trip was not complex with all systems responding normally post trip. Closure of containment isolation valves (CIVs) in multiple systems occurred. Operations responded and stabilized the plant.

"The reactor protection system actuation while critical event is being reported as a 4-hour non-emergency notification per 10 CFR 52.72(b)(2)(iv)(B). Additionally, it is reportable under 10 CFR 52.72(b)(3)(iv)(a) as an event that results in a valid actuation of the CIVs.

"There was no impact on the health and safety of the public or plant personnel.

"The NRC Resident Inspector has been notified."

The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance:

Decay heat removal is via steam bypass to the main condenser. Unit 2 was not affected.

MANUAL REACTOR TRIP DUE TO LOSS OF CONDENSER VACUUM

The following information was provided by the licensee via phone and email:

"At 0748 EDT on 9/27/24, Catawba Unit 2 was manually tripped due to loss of condenser vacuum. The Unit 2 auxiliary feedwater (AFW) system started automatically as expected. Decay heat is being removed by the steam generators and discharging to the condenser.

"Due to the Unit 2 reactor protection system actuation while critical, this event is being reported as a four-hour, nonemergency notification per 10 CFR 50.72(b)(2)(iv)(B). The automatic start of the Unit 2 AFW system is being reported as an eight-hour, nonemergency notification per 10 CFR 50.72(b)(3)(iv)(A).

"On Unit 1, it was determined that at 0746, all trains of the Unit 1 AFW were inoperable when the Unit 1 hotwell temperature exceeded the operability limit for the AFW system. Therefore, this condition is being reported as an eight-hour, nonemergency notification per 10 CFR 50.72(b)(3)(v). The affected safety function was restored on 9/27/24 at 0851 EDT when the Unit 1 hotwell temperature returned below the operability limit for the AFW system.

"There was no impact on the health and safety of the public or plant personnel. 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 loss of vacuum for both Unit 1 and Unit 2 was due to loss of power to cooling tower fans. The suspected cause of loss of cooling tower fans was due to water intrusion due to Hurricane Helene.