Event Notification Report for March 11, 2024

EN Revision Imported Date: 3/11/2024

EN Revision Text: UNANALYZED CONDITION - INADEQUATE FUSES FOR FUEL POOL COOLING

The following information was provided by the licensee via email:

"On 2/9/24 at 1322 EST, it was determined that the unit was in an unanalyzed condition. A review of DC feeder circuit protection schemes identified a circuit for the fuel pool cooling system is uncoordinated due to inadequate fuse sizing. This results in a concern that postulated fire damage in one area could cause a short circuit without adequate protection, leading to the unavailability of equipment credited for in 10 CFR 50 Appendix R, Fire Safe Shutdown. This condition is not bounded by existing design and licensing documents; however, it poses no impact to the health and safety of the public or plant personnel. Therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B).

"The postulated event affects the following fire zones: fire areas 6S and 6N (within the Unit 2 reactor building). Compensatory actions for affected fire areas have been implemented. An extent of condition review is being performed.

"The NRC Senior Resident Inspector has been notified."

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

Fire watches have been established in the affected areas. These will be maintained until the protection scheme is revised.

* * * UPDATE ON 03/08/24 FROM PAUL BOKUS TO TOM HERRITY * * *

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

"On 03/08/24 at 1418, extent of condition reviews identified circuit(s) in the Units 2 and 3 Reactor Protection Systems (RPS) which are also uncoordinated due to improper fuse sizing. These circuits are not bounded by existing design and licensing documents for 10 CFR 50 Appendix R Fire Safe Shutdown and, therefore, this event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(B). This event poses no impact to the health and safety of the public or plant personnel.

"The postulated event affects the following fire areas: 32, 33, 38 and 39 (Units 2 and 3 Switchgear Rooms). In accordance with procedural requirements, compensatory actions for the affected fire areas have been implemented and will remain until the condition is resolved.

"The NRC Senior Resident Inspector has been notified."

Notified R1DO(Arner)

AGREEMENT STATE REPORT - DAMAGED MOISTURE DENSITY GAUGE

The following summary of information was provided by the Florida Bureau of Radiation Control [the Bureau] via email:

On March 1, 2024, at 1121 EST, the Bureau received a call from Universal Engineering Scientists to report that a Troxler gauge (Model: 3430P, Serial: 86000, 8 mCi Cs-137, 40 mCi Am-241:Be) was run over on a work site. The Cs-137 source rod was extended 12 inches into the ground. The licensee radiation safety officer (RSO) responded and determined that the source rod could not to be retracted. The gauge was placed in a container and shielded for transport to a storage facility in Port St. Lucie where it will be held for evaluation.

The Bureau inspector has been notified and will respond.

Florida Incident No.: FL24-015

AGREEMENT STATE REPORT - LOST SOURCE FOUND

The following is a summary of the information provided by the Louisiana Department of Environmental Quality (LDEQ) via email:

At 2152 CST on March 3, 2024, a lost source was found along Corporate Blvd., Baton Rouge, LA. The device is a Model IC-51 Calibrator with 1000 mCi of Cs-137 as of August 25, 1980. The label on the device indicates the manufacturer was Gulf Nuclear, Inc., of Webster, Texas. LDEQ took possession of the device on March 4, 2024, and has it at the time of this report.

Event Report ID No.: LA20240003


THIS MATERIAL EVENT CONTAINS A 'Less than Cat 3' LEVEL OF RADIOACTIVE MATERIAL

Sources that are "Less than IAEA Category 3 sources," are either sources that are very unlikely to cause permanent injury to individuals or contain a very small amount of radioactive material that would not cause any permanent injury. Some of these sources, such as moisture density gauges or thickness gauges that are Category 4, the amount of unshielded radioactive material, if not safely managed or securely protected, could possibly - although it is unlikely - temporarily injure someone who handled it or were otherwise in contact with it, or who were close to it for a period of many weeks. For additional information go to http://www-pub.iaea.org/MTCD/publications/PDF/Pub1227_web.pdf

OFFSITE NOTIFICATION

The following information was provided by the licensee via email:

"On March 6, 2024, at 1635 PST, with Columbia Generating Station operating at 100 percent power in Mode 1, there was a malfunction in the halogenation/dehalogenation system. This system is used for continuous control of the biological growth in the circulating water and plant service water systems as well as to prevent discharge of halogens to the Columbia River during continuous blowdown. The result of this malfunction was exceeding the established limits of 0.1 milligrams/liter (mg/L) for total residual halogen (TRH) in the station's national pollutant discharge elimination system (NPDES) permit. At the time of discovery, the local indication for TRH was 3.20 mg/L. This was confirmed via a local grab sample. This maximum daily effluent limit is the highest allowable daily discharge, measured during a calendar day. The station NPDES permit requires notification to the Energy Facility Site Evaluation Council (EFSEC).

"The automatic isolation function of the system failed to isolate the continuous blowdown line as did the emergency trip push button. The system was manually secured, and the continuous blowdown line to the Columbia River was isolated. The cause of the issue is under investigation.

"Notification was made to EFSEC on March 6, 2024, at 2303 PST. This event is being reported as a four hour report made in accordance with 10 CFR 50.72(b)(2)(xi) due to a "News Release or Notification of Other Government Agency" related to protection of the environment.

"The NRC Senior Resident Inspector has been notified."

TECHNICAL SPECIFICATION VIOLATION

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

"On March 7, 2024, at 1142 PST, an operator trainee operating the reactor under the direction of a licensed operator initiated a planned manual scram. Following the planned manual scram, the licensed operator did not switch the console switch to 'off' or remove the key from the console. The reactor did not meet the definition of 'reactor secured' and thus the staffing requirements of technical specification 6.1.3 were still required to be met. The licensed operator then left the control room, securing the door on their way out. At 1200 PST, a licensed senior reactor operator (SRO) entered the control room and found the key in the console with the switch in the 'operate' position. This SRO placed the switch in the 'off' position, secured the key, logged the action, and notified the Director. Throughout the duration of the event, all control rods were fully inserted."

Project Manager (Wertz) will be contacted. Oregon Department of Energy and the Oregon Radiation Protection Services will be notified.

EN Revision Imported Date: 3/11/2024

EN Revision Text: FITNESS FOR DUTY

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

A non-licensed supervisor had a confirmed positive fitness for duty test. Unescorted access for the individual has been denied at all Dominion Energy sites. The NRC Senior Resident Inspector has been notified.

ESSENTIAL CHILLED WATER TRAINS DECLARED INOPERABLE

The following information was provided by the licensee via email:

"On 3/9/2024 at 2126 CST, train C essential cooling water was declared inoperable due to a through-wall leak on the discharge vent line. This would also cascade and cause train C essential chilled water to be inoperable.

"On 3/10/2024 at 0353 CDT, train B essential chilled water was declared inoperable due to chilled water outlet temperature greater than 52 degrees F following startup of essential chiller 12B. Chilled water outlet temperature was adjusted to less than 52 degrees F at 0440 CDT, and train B essential chilled water was declared operable.

"This condition resulted in the inoperability of two of the three safety trains required for the accident mitigating functions including: high head safety injection, low head safety injection, containment spray, electrical auxiliary building HVAC, control room envelope HVAC, and essential chilled water.

"This is an 8 hour reportable condition per 10CFR50.72(b)(3)(v)(D) because it could affect the ability to mitigate the consequences of an accident."

The licensee notified the NRC Resident Inspector.