Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 50190 | 12 June 2014 02:40:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Halon Gas Release in Unit 2 Cable Spreading Room | Release of Halon into the Unit 2 Cable Spreading Room. No indication of fire in the area. HU3.1 (Toxic, corrosive, asphyxiant or flammable gases in amounts that have or could adversely affect normal plant operations) was declared at 2154 CDT due to Halon release and Oxygen levels below safe habitability conditions (19% oxygen). Ability still exists to maintain safe operations and safely shut down the reactor. No adverse plant response or control board alarms indicated. No smoke or fire in the room and access is provided with SCBA. Escalation criteria would be if not able to maintain safe operations or safely shut down the reactor. Exit criteria would be when normal oxygen levels are restored to Unit 2 Cable Spreading Room. Local NRC resident notified at 2223 CDT. Unit 2 is stable at 100% power. Unit 1 was not affected and remains stable at 100% power. The licensee notified the State of Texas, the local counties, and the NRC Resident Inspector. Notified DHS, FEMA, and NICC. FEMA NWC and Nuclear SSA were notified via email.
At 0330 CDT the Unusual Event was terminated. The licensee notified the NRC Resident Inspector. Notified R4DO (Werner), NRR (Uhle), IRD (Grant), DHS, FEMA, and NICC. FEMA NWC and Nuclear SSA were notified via email. | ||
| ENS 49606 | 4 December 2013 19:50:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unusual Event - Loss of Startup Power Due to a Cut Cable | At 1343 CST on 12/04/2013, Comanche Peak Nuclear Power Plant experienced a loss of safeguards electrical power when 345KV transformer XST2 lost power from offsite while 138KV transformer XST1 was out of service for maintenance. Non-Safeguards electrical power remained energized. Both Units remain at power in Mode 1. Both units Emergency Diesel Generators automatically started and all safeguards busses were re-energized from the Emergency Diesel Generators. All ESF systems functioned as expected and the Turbine Driven Auxiliary Feedwater Pump automatically started as designed. Operators reduced reactor power to maintain reactor power less than 100 percent rated thermal power. At 1350 CST, the licensee declared an Unusual Event due to losing both startup transformers. The cause of the loss of the second start up transformer was a cut cable. No one was injured during this event. The licensee informed State and Local Government Agencies and the NRC Resident Inspector. Notified other Federal Agencies (DHS SWO, FEMA Ops, DHS NICC, and Nuclear SSA via email).
Correction to initial event report description; actual loss of electrical power time was 1341 CST. Include 8-HR Non-Emergency report for Specified System Actuation for automatic start of Auxiliary Feedwater and Emergency Diesel Generators. Notified the R4DO (Vasquez).
Comanche Peak terminated from the Unusual Event at 1717 CST on 12/05/13. Offsite power has been restored to both safeguard busses on both units via the transformer XST2. Work continues on transformer XST1. Comanche Peak Units 1 and 2 continue to operate at 100% power. The licensee has notified the NRC Resident Inspector. Notified R4DO (Vasquez), NRR EO (Bahadur), IRD MOC (Gott), and DHS SWO, FEMA Ops, DHS NICC, and Nuclear SSA via email. | Emergency Diesel Generator Auxiliary Feedwater | |
| ENS 47205 | 27 August 2011 06:56:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Entry Into Eal Hu 4-1 | The licensee declared a Notice of Unusual Event per emergency plan condition HU 4-1 due to a security event. Contact the Headquarters Operations Officer for details. The licensee notified the NRC Resident Inspector. * * * UPDATE FROM DANNY BRADFORD TO PETE SNYDER AT 0410 EDT ON 8/27/11 * * * The Notice of Unusual Event has been terminated. Contact the Headquarters Operations Officer for details. Notified: R4DO (Haire), NRR (Bahadur), DHS (Knox), FEMA (Blankenship). | ||
| ENS 46625 | 18 February 2011 16:45:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event- Excessive Leakage from a Charging System | At 1045 CST, on 2/18/11, Comanche Peak Unit 1 declared an Unusual Event related to excessive leakage from the charging system. The 40 GPM leakage was in excess of the specified limit of 25 GPM. At 1121 CST, the charging system leakage was verified isolated. Unit 1 is in stable condition and remains at 100% power. No offsite assistance is required at this time.
At 1311 EST, Comanche Peak Nuclear Power Plant has terminated the Unusual Event. The leaking valve in the charging system has been isolated reducing the leakage to zero. Repairs to the valve are in planning." The licensee notified the NRC Resident Inspector. The licensee notified the Texas Department of Public Safety and will be making a press release to the local press. Notified R4DO (Gaddy), IRD (Gott), NRR EO (Thorp), DHS (McDonald) and FEMA (Via).
This is a follow-up notification to inform the NRC that Comanche Peak Nuclear Power Plant is retracting Event Number 46625, the Unusual Event declaration reported on February 18, 2011 at 10:45 Central Standard Time. The declaration was made based on EAL SU8.1, (Reactor Coolant System) RCS Leakage, and was terminated on February 18, 2011 at 13:11 Central Standard Time. The declaration is retracted because the source of the leakage was from the Chemical and Volume Control System (CVCS) and not from the Reactor Coolant System. The licensee has notified the NRC Resident Inspector. Notified R4DO (Campbell) | Reactor Coolant System |