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| Start date | Title | Description | Topic | |
|---|---|---|---|---|
| ENS 57026 | 13 March 2024 01:11:00 | Loss of Power to Containment Radiation Monitors | The following information was provided by the licensee via phone and email: On March 12, 2024, at 2111 EDT, a valid containment ventilation isolation train 'A' and 'B' signal was received due to a spurious loss of power to 1EMF-38 (containment particulate radiation monitor) and 1EMF-39 (containment gas radiation monitor). The power to 1EMF-38 and 1EMF-39 was restored. 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: There were no plant evolutions ongoing at the time of the event and the cause of the loss of power is under investigation. There was no impact to Unit 2.
After further review of the event, it was determined the actuation of the associated containment ventilation isolation train 'A' and 'B' was not valid. This is due to the loss of power being associated with the control room modules for 1EMF-38 and 1EMF-39, and not a result of an actual sensed parameter or plant condition. Therefore, this event notification is being retracted. The NRC Resident Inspector has been notified. Notified R2DO (Miller) | |
| ENS 49161 | 30 June 2013 21:20:00 | Auxiliary Feedwater System Declared Inoperable Due to High Hotwell Temperatures | The Auxiliary Feedwater System was inoperable due to elevated hotwell temperatures from 1720 to 1739 EDT on 6/30/13. At no time was there a risk to the health and safety of the public. The elevated hotwell temperatures resulted from the loss of multiple cooling tower fans due to a lightning strike. Cooling tower fans and hotwell temperatures have been restored. Power was slightly reduced solely to maintain condenser vacuum until cooling tower fans were restored. At Catawba, the hotwell is a credited water supply for the auxiliary feedwater system. The unit is currently in a power ascension back to 100%. No other plant equipment was affected by the lightning strike. The licensee will be notifying the state warning points in both North and South Carolina and local warning points in Gaston, York, and Mecklenburg counties. They have notified the NRC Resident Inspector.
Catawba Nuclear Station is retracting EN #49161 based on completion of evaluation of auxiliary feedwater system operability. The engineering department performed this evaluation using existing plant conditions during the event to verify existing safety analyses remain bounding and conservative. The evaluation concluded that sufficient volume of secondary condensate was available below the required temperature from the Upper Surge Tanks (USTs), in combination with the hotwell inventory as normally aligned, for the auxiliary feedwater system to remain operable during this event. This condition is not reportable under 10CFR50.72(b)(3)(v)(B). The licensee will notify the NRC Resident Inspector, State and Counties. Notified the R2DO (King). | |
| ENS 48348 | 26 September 2012 19:15:00 | Technical Specification 3.0.3 Entered Due to Surveillance Testing Not Being Completed as Required | Pressurizer Pressure LO Instrument surveillance testing was discovered to not have been completed as required. Existence of an internal jumper on solid state protection system input to logic cards prevented complete circuit testing. Unit 1 and unit 2 entered Technical Specification (TS) 3.0.3 at 1515 hours. Alternate method of surveillance testing on one of the trains was completed and TS 3.0.3 was exited on Unit 1 at 2203 EDT and Unit 2 at 2132 EDT. The licensee plans to complete surveillance testing on the second train before 1515 hours on 9/27/12. The licensee is currently in TS 3.3.2. The licensee has notified the NRC Resident Inspector. The states of North Carolina and South Carolina will be notified. Local county governments of York, Gaston, and Mecklenberg counties will also be notified.
Catawba nuclear station is retracting EN #48348 for both units 1 and 2 based on completion of testing and investigation of system operability. The testing determined that both units respective train 'A' and 'B' pressurizer pressure low were operable and would have functioned as needed. This condition is not reportable under 10 CFR 50.72(b)(3)(ii)(B) and 10 CFR 50.72(b)(3)(v)(D). The licensee has notified the NRC Resident Inspector. R2DO (O'Donohue) notified. | |
| ENS 40359 | 28 November 2003 03:55:00 | Component Cooling System Surge Tank Supports May Fail During a Seismic Event | During an ISI inspection of the component cooling system, it was discovered that several of the surge tank support stiffener plates were missing due to a design change that was never fully implemented. This condition creates a question as to the adequacy of the tanks to withstand a seismic event. This deficiency affects both trains of component cooling on Units 1 and 2. The problem will be corrected on Unit 1 while it is in its refueling outage. Work on the Unit 2 "A" train is currently ongoing, making that train of the component cooling system inoperable, therefore, putting the plant in a 72 hour LCO. When work on the "A" train is completed, they will exit the LCO, but re-enter it when work begins on the "B" train. Licensee will notify the NRC Resident Inspector, the State and local agencies.
The subject EN #40359 was made on 11/28/03. Following additional review by the licensee, this event was determined to not meet the reportability requirements of 10 CFR 50.72. The event was determined to not result in a condition that could have prevented fulfillment of a safety function, as the tank supports were analyzed to withstand a seismic event. In addition, the event did not result in the plant being in an unanalyzed condition. The condition did not prevent the fulfillment of a safety function or system that is needed to remove residual heat or mitigate the consequences of an accident. The licensee plans to notify the NRC Resident Inspector. Notified R2DO Caudle Julian. | Unanalyzed Condition |