Semantic search
| Entered date | Event description | |
|---|---|---|
| ENS 48313 | 17 September 2012 15:23:00 | At 0858 hrs. (CDT), Corporate Communications notified the control room that there was a communication issue with the emergency siren router. Based on the report, all sirens for the Alert Notification System within the Emergency Planning Zone (EPZ) were declared nonfunctional and notifications were completed. Local law enforcement has been notified in the required surrounding counties and compensatory measures are in place to ensure notification of the public in case of an actual emergency. Troubleshooting of the siren's communication system revealed that a peripheral router power supply had failed. The power supply was replaced at 0935 and router restarted. At 0955 sirens were restored to the counties of Harrison and Pottawattamie in Iowa. Communications were restored to all but one siren, in Washington County Nebraska by 1031, with that one siren (Siren 35) restored at 1103. All repairs completed and retested satisfactorily with proper communications confirmed with each siren. The power supply failure resulted in 2.1 hours with the sirens being unavailable. Notifications have been completed with compensatory actions by local law enforcement secured. This is being reported per 10CFR50.72(b)(3)(xiii) for 'Any event that results in a major loss of emergency assessment capability, off site response capability, or communications capability.' The licensee has notified the NRC Resident Inspector. |
| ENS 47870 | 27 April 2012 16:02:00 | A non-licensed supervisory employee was determined to be under the influence of illegal drugs during a random test. The employee's access to the plant has been terminated. Contact the Headquarters Operations Officer for additional details. The licensee has notified the NRC Resident Inspector. |
| ENS 47862 | 25 April 2012 17:22:00 | A non-conservative error was identified in the Proto-Flo input calculation FC06644 for LPSI (Low Pressure Safety Injection) flow post-RAS (recirculation actuation signal). The calculation used an incorrect (non-conservative) input for LPSI pump performance. Also, the associated procedure (EOP/AOP Attachment 11) as written does not provide adequate direction during the Alternate Hot Leg Injection mode of operation. EOP/AOP Attachment 11 (Alternate Hot Leg Injection) used 140 psia as the entry point. The LPSI pumps may not be able to meet minimum flow requirements at this pressure, affecting core cooling and possibly resulting in pump damage. Also the EOP/AOP attachment directs the operator to verify that flow is approximately 400 gpm as indicated on FIC-326. If 400 gpm cannot be achieved the contingency is to open any LPSI loop injection isolation valve. This step would not depressurize the RCS low enough to allow the 400 gpm flow rate to be achieved which would cause insufficient flow. Therefore, it is reasonable to conclude that the referenced procedural guidance may not be able to complete the safety function of providing adequate core cooling during the Alternate Hot Leg Injection mode of operation under a worst case scenario. Therefore, this condition is an unanalyzed condition and reportable under 10CFR50.72(b)(3)(ii)(B). The licensee has notified the NRC Resident Inspector. |
| ENS 47473 | 23 November 2011 01:43:00 | During walkdown of scheduled work it was discovered that HCV-335 (Shutdown Cooling Heat Exchanger Inlet Header Isolation Valve) would not be able to be manually positioned open due to a missing idler gear key. Upon a loss of instrument air, HCV-335 would have failed closed, interrupting shutdown cooling flow with no ability to open HCV-335 manually. Alternate shutdown cooling pump and paths were available at the time of discovery. No loss of instrument air or interruption in shutdown cooling flow occurred while preparing to align alternate shutdown cooling. An 8 hour LCO under Technical Specification 2.8.1(3)2 was entered at 1700 CST. Alternate shutdown cooling was established on a containment spray pump as allowed by procedure. The 8 hour LCO was exited at 2306 CST. A replacement idler key has been fabricated for HCV-335. The licensee notified the NRC Resident Inspector. * * * RETRACTION FROM ERICK MATZKE TO PETE SNYDER AT 1654 EST ON 12/16/11 * * * Additional analysis has determined that the shutdown cooling system was capable of performing its design safety functions during the time that the idler key was missing. Therefore this event is being retracted. The licensee notified the NRC Resident Inspector. Notified R4DO (Walker). |
| ENS 47033 | 7 July 2011 14:50:00 | Power has been removed from 10 (out of 101) sirens due to flooding conditions. (Three) out of 5 sirens in Pottawattamie county, 4 of 18 in Harrison county and 3 of 78 in Washington county. There are compensatory measures in place to ensure notification to any members of the public that may still be in these areas. The station is also suspending testing and reporting (performance indicator) data for these sirens in accordance with NEI 99-02. All of these sirens serve areas for which there are no residents requiring evacuation. This is being reported per 10CFR50.72(b)(3)(xiii)) for 'Any event that results in a major loss of emergency assessment capability, offsite response capability, or communications capability'. The licensee notified the States of Nebraska and Iowa, the Counties of Harrison, Washington and Pottawattamie and the NRC Resident Inspector of this report. |
| ENS 46953 | 13 June 2011 14:30:00 | At 0500 CDT, the lift station #4 sewage system, South of the Fort Calhoun Station Administration building, was released to the Missouri River. The release was a mixture of ground water and sewage; samples were taken by chemistry but dilution concentration is unknown. Approximately 105 gpm release started around 0500 on 6/13/2011. This condition is being reported pursuant to 10 CFR 50.72(b)(2)(xi) for an event related to the protection of the environment for which a notification of governmental agencies is required. Applicable governmental agencies have been notified per plant procedures. The licensee notified the State of Nebraska at 1200 CDT. The licensee also notified the NRC Resident Inspector. |
| ENS 46932 | 7 June 2011 11:21:00 | At 0940 CDT an alert (HA 2, EAL 1) for operating Mode less than 210 degrees F (was) declared for a fire affecting the operability of plant safety systems required to establish or maintain safe shutdown. Time of fire was 0930 CDT. Control room received multiple alarms (and) 480 V bus 1B4A amps were observed to be oscillating. Bus 1B4A was secured (and) buses 1B3A and 1B3A-4A were lost. Halon activated properly. (At) 0956 CDT all notifications to applicable personnel were completed. At 1000 CDT 4160v buses 1A2 / 1A4 were secured to facilitate fire fighting. Spent fuel pool cooling was lost (as a result of the de-energized busses and the licensee) entered AOP-36 for loss of SFP cooling. Heat up rate (was) determined by STA. Current time to boil for SFP is 88.3 hrs. Spent fuel pool cooling is currently back in service. This condition is being reported pursuant to 10 CFR 50.72(a)(1)(i) for declaration of an emergency class specified in the licensee's approved emergency plan. Plant was in AOP-1 for flood mitigation. The fire is not believed to be flood related. Plant remains in AOP-1. At about 0930 CDT the licensee noted fire in the west switchgear room. The fire brigade responded and found a room filled with smoke but no active fire. Halon did discharge in the room. At 0956 CDT, offsite assistance was called and Blair Fire Department responded to the site. Blair Fire Department confirmed no active fire in the switchgear room. All offsite power remained available as well as the emergency diesel generators if needed. The licensee is currently attempting to ventilate the room. A thorough inspection of the affected area and determine the caused of the electrical fault will be facilitated once the room has been fully ventilated. The licensee has notified appropriate State and local government. The licensee notified the NRC Resident Inspector. A media or press release is also anticipated.
Entered Alert for HA 3, EAL 1 access to a vital area (Switchgear and Turbine Building basement) due to toxic gases present from the fire in the West Switchgear room. The licensee entered HA 3 at 1144 CDT. Their exit criteria is that the switchgear room is cleared for unimpeded access. The licensee has notified the NRC Resident Inspector. Notified the R4IRC (Kennedy)
At 1315 CDT, Fort Calhoun Nuclear Station has exited Alert HA 2, EAL. It has been confirmed that no fire remained in the vital area. Plant shutdown cooling remained in-service and spent fuel pool cooling was restored and temperature verified to be lowering. The licensee has also exited Alert HA 3, EAL 1 after it was confirmed that the environmental conditions from the event and associated Halon discharge does not affect the ability to safely operate or safely shutdown the reactor due to being in Mode 5 and shutdown cooling remaining in-service. Fort Calhoun remains in Unusual Event HU 1, EAL 5 for River Level greater than 1004' elevation as reported under EN #46929. The licensee has notified appropriate State and local government. The licensee has also notified the NRC Resident Inspector. The NRC made notifications of the event termination to DHS, FEMA, DOE HHS and USDA. |
| ENS 46689 | 22 March 2011 14:22:00 | At 10:58 CDT, today during the performance of IC-ST-IA-3010B, I&C found NG-HCV-400A-A3, CCW INLET VALVE HCV-400A NITROGEN SUPPLY ISOLATION VALVE, closed which is required to remain open for VA-3A to remain operable. This valve supplies backup nitrogen to VA-3A CCW cooler isolation valve HCV-400A on loss of instrument air to maintain cooling flow to the ventilation during an accident condition. While the nitrogen valve NG-HCV-400A-A3 was closed, performance of IC-ST-IA-3010B on VA-3B, CONTAINMENT AIR RECIR FAN, placed the containment cooler in an inoperable status. This led to Technical Specification 2.0.1 entry due to both trains of cooling being inoperable. The cause for the mispositioning of NG-HCV-400A-A3 is unknown at this time. The inoperability of VA-3A along with VA-3B rendered the containment cooling trains unavailable to perform their safety function during an accident condition. This condition is being reported pursuant to 10 CFR 50.72(b)(3)(V)(D) for mitigating the consequences of an accident. FCS entered into Technical Specification at 10:58 CDT and exited Technical Specification at 11:14 CDT. The licensee notified the NRC Resident Inspector. |