Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 56811 | 22 October 2023 16:40:00 | The following information was provided by the licensee via fax and phone: On October 22, 2023, at 1149 CDT, with the reactor at 100 percent core thermal power and steady state conditions, the Cooper Nuclear Station secondary containment differential pressure exceeded the Technical Specification (TS) Surveillance Requirement (SR) 3.6.4.1.1 limit of -0.25 inches water gauge. The condition existed for approximately 80 seconds until the reactor building ventilation system responded to restore differential pressure to normal. Investigations identified a hinged duct access hatch found open. The hatch was closed and latched, and ventilation system parameters were returned to normal. There were no radiological releases associated with this event. Declaring secondary containment inoperable as a result of not meeting TS SR 3.6.4.1.1 is reportable under 10 CFR 50.72(b)(3)(v)(C) and (D) as an event or condition that could have prevented the fulfillment of a safety function needed to control the release of radioactive material and mitigate the consequences of an accident. The NRC Senior Resident Inspector has been informed. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: At the time the licensee notified the NRC Headquarters Operations Officer, the cause of the hinged access duct being open had not been determined. This event has been added to the licensee's corrective action program. |
| ENS 56509 | 8 May 2023 06:25:00 | 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.
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.
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). |
| ENS 55703 | 13 January 2022 12:03:00 | The following information was provided by the licensee via fax: On 1/13/2022 at 0806 CST, Nebraska Public Power District was notified by Atchison County Missouri of a spurious actuation of (Cooper Nuclear Station) (CNS) Emergency Siren 2113 near Rockport, Missouri from approximately 0800 to 0805 CST. Nebraska Public Power District will issue a press release for this event. The CNS Emergency Alert System (EAS) was not activated. This condition is reportable under 10 CFR 50.72(b)(2)(xi) for any event or situation for which a news release is planned or notification to other government agencies has been or will be made which is related to heightened public or government concern. The NRC Senior Resident Inspector has been informed. |
| ENS 52315 | 23 October 2016 23:41:00 | At 1908 CDT on 10/23/16, elevated vibration readings were identified on Cooper Nuclear Station (CNS), Control Room Emergency Filter System (CREFS) supply fan A. Vibration readings were evaluated by Engineering and were determined to be indicative of bearing failure on supply fan A. The Control Room declared CREFS inoperable and entered LCO 3.7.4, Condition A, which requires restoration of CREFS to operable status in 7 days. Repair activities have been initiated for this condition. The plant is currently in Mode 5, with refueling activities and OPDRVs (Operation with Potential to Drain Reactor Vessel) in progress. CNS is not currently in the mode of applicability for a USAR defined accident. This condition is being conservatively reported under 10 CFR 50.72(b)(3)(v)(D) as a single train safety system that is required to be OPERABLE during situations under which significant radioactive releases can be postulated. The NRC Resident Inspector has been notified. |
| ENS 52070 | 7 July 2016 09:48:00 | At 0610 CDT on 7/7/2016, Cooper Nuclear Station confirmed that the Shubert radio transmission tower was not functioning. This affects the tone alert radios used to notify the public in the event of an emergency condition. This is considered to be a major loss of the public prompt notification system capability and is reportable under 10CFR50.72(b)(3)(xiii). Nemaha, Richardson and Atchison county authorities within the 10 mile EPZ were notified of the condition and the effect on the tone alert radios and will utilize the backup notification method making this condition reportable under 10CFR50.72(b)(2)(xi) for notification of other government agencies. Estimated return to service time is unknown. The cause of the failure is unknown. The NRC Resident Inspector has been notified of this condition. |
| ENS 51887 | 27 April 2016 12:25:00 | At 0823 CDT on 4/27/2016, Cooper Nuclear Station was notified by the National Weather Service that the Shubert radio transmission tower was not functioning. This affects the tone alert radios used to notify the public in the event of an emergency condition. This is considered to be a major loss of the public prompt notification system capability and is reportable under 10CFR50.72(b)(3)(xiii). Nemaha, Richardson and Atchison county authorities within the 10 mile EPZ (Emergency Planning Zone) were notified of the condition and the effect on the tone alert radios and will utilize local route notification (backup notification method) making this condition reportable under 10CFR50.72(b)(2)(xi) for notification of other government agencies. Estimated return to service time is unknown. The cause of the failure is a loss of communication with the tower. The NRC Senior Resident Inspector has been notified of this condition. |
| ENS 51347 | 26 August 2015 13:20:00 | On 8/26/2015, it was determined that a report to the NRC under 10 CFR 50.72(b)(2)(xi) may have been missed. The station is making this report due to the station making a courtesy call to a State agency regarding release of radioactive waste from the site as non-radioactive material. The original event involved a release of 14 bags of debris from the Administration Building roof prior to survey results being obtained. The bags were recovered from the local landfill and a determination was made that the amount of material temporarily removed from the Protected Area was below NRC reporting limits per 10 CFR 20.2201 'Reports of theft or loss of licensed material.' On 5/29/13 a courtesy phone call was made to the Nebraska Department of Health and Human Services (Radiation Control Program) informing the authority of the event. There were no state notification requirements based on the low level of licensed material released (and then recovered) from the site. This is a four hour report made in accordance with 10 CFR 50.72(b)(2)(xi) as 'Any event or situation, related to the health and safety of the public or on-site personnel, or protection of environment, for which a news release is planned or notification to other government agencies has been or will be made.' There was no overexposure to a member of the public. The NRC Resident and State of Nebraska have been informed. |
| ENS 50338 | 3 August 2014 20:01:00 | This event is being reported per 50.72(b)(2)(xi), 'Any event or situation, related to the health and safety of the public or on-site personnel, or protection of the environment, for which a news release is planned or notification to other government agencies has been or will be made.' At 1549 CDT, August 3, 2014, the National Weather Service inadvertently issued a Civil Emergency Message over their pager notification system during preparations for an upcoming (Cooper Nuclear Station) Emergency Drill. A follow up message was issued by the National Weather Service at 1601 CDT stating that the Civil Emergency Message was a test message and should be disregarded. A media/press release is planned. The licensee has notified the NRC Resident Inspector, State, and local authorities. |
| ENS 48301 | 12 September 2012 09:33:00 | A planned maintenance activity at Cooper Nuclear Station will remove the TSC (Technical Support Center) ventilation system from service. The TSC ventilation system will be rendered non-functional during this maintenance period. The repair to the TSC ventilation is expected to last less than 2 days. If an emergency is declared requiring TSC activation during this period, the TSC will be staffed and activated using existing emergency planning procedures unless uninhabitable due to ambient temperature, radiological, or other conditions. CNS Station procedures provide appropriate monitoring and compensatory measures to ensure habitability of the TSC and, if necessary, instructions for relocation of TSC personnel should the need arise. In the event of TSC activation, maintenance will be expedited to restore ventilation to service. This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to the loss of an Emergency Response Facility (ERF). An update will be provided once the TSC ventilation system has been restored to normal operation. The licensee notified the NRC Resident Inspector. * * * UPDATE FROM CURTIS MARTIN TO PETE SNYDER AT 1026 EDT ON 9/13/12 * * * At 0910 CDT on 9/13/12 the TSC ventilation system has been returned to service. The licensee notified the NRC Resident Inspector. Notified R4DO (Lantz). |
| ENS 48230 | 24 August 2012 17:33:00 | At 1332 CDT on 8/24/12 a failure of power supply RMA-ES-53A was indicated in the Control Room. The power supply was declared Non-Functional. This failure results in the loss of ability to remotely measure and quantify radiological conditions (radiation levels) for multiple areas in the Reactor Building. The power supply provides power to RMA-RA-1 through RMA-RA-10. RMA-RA-11 through RMA-RA-30 remain fully functional and indicating normally. The loss of ability to monitor and quantify radiological conditions in multiple areas of the Reactor Building represents a major loss of emergency assessment capability per 10 CFR 50.72(b)(3)(xiii). As specified by station procedures, compensatory measures have been implemented to survey affected areas by installation of portable monitoring devices and trending radiological conditions. RMA-RA-1 through RMA-RA-10 are used for EAL determinations. The Work Week Director has been notified to initiate repairs. The licensee has notified the NRC Resident Inspector. |
| ENS 47753 | 19 March 2012 08:57:00 | At approximately 0119 CDT on 3/19/12, Cooper Nuclear Station was informed by the National Weather Service that the Shubert radio transmission tower was not working. This affects the tone alert radios Cooper Nuclear Station provides to members of the public to notify them of an emergency condition. This is considered to be a major loss of the Public Prompt Notification System capability, and is reportable under 10CFR50.72(b)(3)(xiii). Local county authorities within the 10 mile EPZ have been notified of the condition of the Shubert radio transmission tower and the affect on this tone alert radios and will utilize Local Route Notification (backup notification method.) At approximately 0635 CDT, the National Weather Service reported that the Shubert radio transmission tower had been restored and tested satisfactorily. The licensee has notified the NRC Resident Inspector and local authorities of the condition. |
| ENS 41730 | 26 May 2005 18:38:00 | On March 14, 2005, a fire occurred in a trash receptacle adjacent to a shipping container, in the Cooper Nuclear Station (CNS) Multi-Purpose Facility (MPF). The MPF is a machine shop attached to the Radwaste Building inside the Protected Area of CNS. At 0249 upon receipt of the fire alarm in the MPF and alarms received for the automatic start of station fire pumps, Control Room Operators entered the CNS Fire Procedure and dispatched a Station Operator (SO) to the scene. At 0251 the SO was permitted to fight the fire with a fire hose, and the fire brigade was mobilized. The SO extinguished the fire in the trash receptacle at 0258. The SO reported to the Fire Brigade Leader that he had felt heat from the walls of the adjacent shipping container, but was unable to access it due to being locked. At 0308 the Fire Brigade gained access to the shipping container and reported a small fire inside. At 0313 the fire was extinguished. Subsequently, the embers were overhauled, and the reflash watch was set. No further reflashes occurred. All applicable steps in the Fire Procedure were completed. The apparent cause of the fire was the failure of a large overhead light. Because these were regarded as two separate fires, CNS did not enter the Emergency Action Level (EAL) for a Notice of Unusual Event (NOUE.) Further review, continued benchmarking with other utilities, and consideration of the lack of a consistent treatment for declaring a fire being out, has prompted CNS to determine that a declaration of NOUE should have been made. Upon making that determination, CNS is required to notify the NRC in accordance with the guidance of NUREG-1022, Revision 2. The event has been concluded and the basis for the emergency no longer exists. The Licensee will notify both state and local agencies and has informed the NRC Resident Inspector. The licensee stated that the discovery that a declaration of NOUE should have been made occurred at 1700 CDT 05/26/05. |