|Entered date||Site||Region||Reactor type||Event description|
|ENS 55690||5 January 2022 13:36:00||Fort Calhoun||NRC Region 4||CE||The following information was provided by the licensee via email: At 0907 CST, a small fire was reported in the Intake Structure at Fort Calhoun Station. Offsite fire departments were notified at 0909 CST and responded at 0922 CST. Fire was confirmed extinguished at 0949 CST. Fire was extinguished using offsite resources per the Station Fire Plan. There were no injuries reported. The fire occurred in the Non-Radiological area of the plant and there was no release of radioactivity or hazardous materials.|
|ENS 55566||8 November 2021 13:05:00||Fort Calhoun||NRC Region 4||At 1015 CST, a report was made to the State of Nebraska Department of Environment and Energy (NDEE) based on the analytical report for soil samples from the area surrounding the removed FO-10, Auxiliary Boiler Fuel Oil Storage Tank. The tank was removed as part of Fort Calhoun Station decommissioning and soil samples were tested due to historical information from a similar tank removal earlier this year (June 2021). The soil contamination levels are from the historic use of the tank. The contamination levels (of Volatile Organic Compounds) are above the lab reporting limits and thereby reportable to the State of Nebraska Department of Environment and Energy. There was no contamination noted in the groundwater samples. The NDEE will determine what, if any, remediation may be required. The state NDEE requested the District utilize their Spill Form because this is the simplest method of State notification for tanks exempted due to 40 CFR280.10(c)(4). No active petroleum spills are in progress and appropriate remediation actions will be taken in accordance with Nebraska State regulation and guidance. The licensee will notify NRC Region 4 personnel.|
|ENS 55306||15 June 2021 15:38:00||Fort Calhoun||NRC Region 4||At 1230 CDT a report was made to the State of Nebraska Department of Environment and Energy (NDEE) based on the analytical report for soil samples from the area surrounding the removed FO-1, Emergency Diesel Generator Fuel Oil Storage Tank, and the removed FO-32, TSC/Security Fuel Oil Tank. The tanks were removed as part of Fort Calhoun Station decommissioning and soil samples were tested due to soil discoloration at the time the tanks were pulled. The soil contamination levels are from the historic use of the tank. The contamination levels are above the lab reporting limits and thereby reportable to the State of Nebraska Department of Environment and Energy. The NDEE will determine what, if any, remediation may be required. The state NDEE requested the District utilize their Spill Form because this is the simplest method of State notification for tanks exempted due to 40CFR280.10(c)(4). No active petroleum spills are in progress and appropriate remediation actions will be taken in accordance with Nebraska State regulation and guidance. The licensee notified the NRC Region IV Office.|
|ENS 54907||23 September 2020 18:56:00||Fort Calhoun||NRC Region 4||At 1528 CDT, a fire was reported in containment. Fire was extinguished using a portable fire extinguisher by dedicated fire watch. Offsite fire departments responded at 1541 CDT and the fire was confirmed extinguished at 1601 CDT. There were no injuries reported. The state Fire Marshal of Nebraska has been notified. There was no release of radioactivity or hazardous materials. The following statement is planned to be released to the media: A small industrial fire broke out this afternoon at OPPD's Fort Calhoun Station, the decommissioning nuclear plant just south of Blair, Nebraska. It had been put out by fire extinguishers before firefighters arrived. No release of radioactivity occurred. All employees and contractors are accounted for and safe. Based on our preliminary investigation, the fire appears to have been caused by a torch used for cutting. Firefighters are using a thermal gun to identify any potential remaining hot spots. The plant is undergoing decommissioning and all spent nuclear fuel is fully secured in industry-standard dry cask storage, located away from the site of today's fire. The public remains safe and the facility remains secure. All work at the site is on a temporary hold. Safety remains our highest priority. OPPD will provide additional information as it becomes available.|
|ENS 53831||16 January 2019 23:51:00||Fort Calhoun||NRC Region 4||At 1908 CST, a fire was reported in an unoccupied exclusion area opening (EAO) enclosure outside of the Fort Calhoun Station protected area. Offsite fire departments responded at 1923 CST and the fire was extinguished by 1930 CST. There were no injuries reported. The State Fire Marshal of Nebraska was notified by the Blair (Nebraska) Fire Department at approximately 1913 CST. His investigation determined the cause to be a malfunctioning heating element in a climate control unit. There was no release of radioactivity or hazardous materials. The climate control unit was clarified to be a ceiling mounted heater in the enclosure. The licensee notified the NRC Decommissioning Inspector.|
|ENS 53125||18 December 2017 10:44:00||Fort Calhoun||NRC Region 4||On December 18, 2017 at 0710 CST, five (5) sirens in the Ft. Calhoun Station Emergency Planning Zone for Pottawattamie County, Iowa, were inadvertently activated for less than one (1) minute. There was no emergency. The plant is permanently offline and undergoing decommissioning. This siren actuation was a result of a Pottawattamie County testing error and was cancelled. The licensee notified the State of Iowa, Pottawattamie County, the National Weather Service, local radio station and informed NRC Region 4 (Browder).|
|ENS 52201||25 August 2016 21:11:00||Fort Calhoun||NRC Region 4||On August 25, 2016, Engineering staff were reviewing a proposed modification to install additional internal flooding protection for the Intake Building staircase down to the Raw Water Pump vault. Fort Calhoun Station determined that the existing Intake Building internal flooding and tornado-borne missile analyses did not sufficiently account for the potential of tornado-borne missiles striking Fire Protection piping in the Intake Building. A tornado-borne missile strike could potentially cause a double-ended rupture of Fire Protection piping in the vicinity of the stairwell down to the Raw Water Pump vault, which could cause flooding and subsequent failure of all four Raw Water Pump motors more quickly than bounded by the Engineering Analysis. The Engineering Analysis uses a postulated crack from a Moderate Energy Line Break per USNRC Branch Technical Position MEB 3-1, vice postulating a double ended pipe rupture. The resulting flow rate from this postulated crack is less than that possible from a tornado-borne missile strike. This condition creates a potential loss of safety function from the Fort Calhoun Station Raw Water System (ultimate heat sink). All four Raw Water Pump motors could potentially become inoperable from flooding caused by a tornado-borne missile impacting the Fire Protection System Piping near the Raw Water vault stairwell prior to operator action to secure both Fire Pumps. This condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) for any event or condition that results in the nuclear power plant being in an unanalyzed condition that significantly degrades plant safety, and per 10 CFR 50.72(b)(3)(v)(D) for any event or condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to mitigate the consequences of an accident. Interim compensatory measures are to isolate the Fire Protection piping in the vicinity of the Raw Water Pump vault stairwell when severe weather is forecast. The NRC Resident Inspector has been notified.|
|ENS 52188||17 August 2016 21:30:00||Fort Calhoun||NRC Region 4||At 1826 (CDT), Operators identified that off-site 161 kV power source predicted post-trip voltage was below the operability limit of 161.3 kV. (Operators) entered AOP-31, 161 kV Grid Malfunctions, Section 1, 161 kV Grid Instability, and declared House Service Transformers T1A-3 and T1A-4 inoperable. (Operators) entered Technical Specification 2.7(2)c. Per Technical Specification 2.7(2)c, 'Both house service transformers T1A-3 and T1A-4 (4.16kV) may be inoperable for up to 72 hours. The loss of the 161kV incoming line renders both transformers inoperable. The NRC Operations Center shall be notified by telephone within 4 hours after inoperability of both transformers.' Per OPPD (Omaha Public Power District) Transmission, grid conditions are currently stable. OPPD Transmission has successfully raised predicted post-trip 161 kV voltage with all predicted voltages meeting or exceeding operability requirement of 161.3 kV as of 1834. Current post-trip predicted voltage is 162.2 kV as of 2029. Lowest observed actual voltage was 163.7 kV. The 161 kV line and transformers T1A-3 and T1A-4 remained available at all times. The licensee notified the NRC Resident Inspector.|
|ENS 52033||22 June 2016 13:02:00||Fort Calhoun||NRC Region 4||At 0841 (CDT) an automatic turbine trip occurred, resulting in an automatic reactor protective system (RPS) actuation due to loss of turbine load. The source of the turbine trip was from the distributed control system (DCS) and is being investigated via a root cause analysis. This was an uncomplicated trip, all systems responded as expected post trip, and the reactor trip recovery procedure was entered at 0852 (CDT). The plant is stable in Mode 3 with a normal electrical line up and decay heat removal via steam dumps to the condenser. The NRC Resident Inspector has been notified.|
|ENS 51917||10 May 2016 19:38:00||Fort Calhoun||NRC Region 4|
During scheduled maintenance, at 1138 CDT, the Fort Calhoun Station Shift Manager was notified via phone call and condition report of an unanalyzed condition which was the result of the maintenance on Shutdown Cooling Heat Exchanger valves. This condition could have led to the inability of the Component Cooling Water (CCW) system to perform its design function of providing a cooling medium for the Containment atmosphere under Loss of Coolant Accident (LOCA) conditions. This was identified by OPPD (Omaha Public Power District) staff engaged in Design Basis Reconstitution. As part of the maintenance, HCV-484, Shutdown Cooling Heat Exchanger AC-4A CCW Outlet Valve, and HCV-481, Shutdown Cooling Heat Exchanger AC-4B CCW Inlet Valve, were opened. Under these conditions, with the assumed single failure loss of DC control power and accident conditions of a LOCA, CCW would be allowed to flow through both shutdown cooling heat exchangers, effectively bypassing flow to the Containment Cooling Units. These conditions are not assumed under plant design basis calculations, and therefore placed the plant in an unanalyzed condition. Following clearance removal at 1535 CDT, both HCV-484 and HCV-481 were returned to service and the condition described above no longer exists. The licensee notified the NRC Resident Inspector.
Discovered 6/15/2016 at 1330 CDT: During the extent of condition review for the above ENS notification, it was discovered that the unanalyzed condition that occurred on 5/10/2016 also occurred five other times during the past 3 years. Details for these additional occurrences will be included in the 60-day Licensee Event Report associated with the original 5/10/2016 ENS notification. The licensee has notified the NRC Resident Inspector. Notified R4DO (Taylor).
|ENS 51807||18 March 2016 18:43:00||Fort Calhoun||NRC Region 4|
During a scheduled surveillance test on 3/18/2016 at 1128 (CDT), Fort Calhoun ultrasonic testing technicians discovered a void on the common shutdown cooling heat exchanger discharge piping. This piping is normally isolated during power operation, and the void does not adversely affect the Containment Spray function, Low Pressure Safety Injection function, or High Pressure Safety Injection function.
This isolated piping with the void is placed in service only during shutdown cooling operation. The fluid height measured was 10.8 inches, compared to the required height of 11.7 inches for the surveillance test. The void could potentially complicate the initiation of shutdown cooling in the required mode of operation. This piping was last tested satisfactory on 12/31/2015. The source of the void is still under investigation. Fort Calhoun maintenance was successful in venting the void on 3/18/2016 at 1704 CDT. The NRC Resident Inspector has been notified.
Following the 8-hour 10 CFR 50.72 notification made on 3/18/16 (EN 51807), further engineering analysis has determined that the ensuing water hammer transient would not have prevented the shutdown cooling system from performing its required safety functions. Specifically, it was found that the resulting system pressure transient would not cause any relief valves to lift and that piping and supports would not be significantly challenged. Therefore, the common shutdown cooling heat exchanger discharge piping remained operable by the detailed analysis. As such, the safety function was not lost and the event notification is being retracted as it is not reportable pursuant to 10 CFR 50.72(b)(3)(v)(B). Notified the R4DO (G Miller).
|ENS 51487||21 October 2015 18:33:00||Fort Calhoun||NRC Region 4||The isolation function when transferring control from the Main Control Room to the Alternate Shutdown Panel (AI-185) for Pressurizer Heater Bank No. 4 (including Groups No. 10, No. 11, and No. 12) has been identified as a potential circuit failure. Identification of the potential circuit failure vulnerability is for Pressurizer Heater Bank No. 4 when isolated from Alternate Shutdown Panel (AI-185) and operated locally from Motor Control Center (MCC-4C1) for Alternate Shutdown Fire Areas 41 (Cable Spreading Room) and 42 (Main Control Room). The vulnerability involves an external hot short affecting the conductor connecting to the control room switch which may keep the 94/10 relay energized and defeat MCC control of the heaters. In a postulated event, a fire in the control room could prevent the heaters from energizing when demanded, or cause the heaters to unintentionally energize. This condition is being reported in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition. Per National Fire Protection Association (NFPA) 805, fire watch is an adequate compensatory measure. Therefore, this vulnerability has been added to the existing NFPA 805 Fire Protection compensatory measure for Fire Area 41. For Fire Area 42, the Main Control Room is continuously staffed, which has been credited as the compensatory measure. The NRC Resident Inspector has been notified.|
|ENS 51439||2 October 2015 10:27:00||Fort Calhoun||NRC Region 4|
At 0905 CDT on 10/02/15, Ft. Calhoun Station declared a Notification of Unusual Event based on criteria in the site security plan. The licensee notified State and local agencies and the NRC Resident Inspector. Notified DHS SWO, DHS NICC, FEMA, and Nuclear SSA via email.
At 1136 CDT, the Unusual Event was terminated based on the fact that criteria for entry into the site security plan no longer exists. The licensee notified State and local agencies and the NRC Resident Inspector. Notified R4DO (Taylor), R4RA (Dapas), NRR ET (Dean), NSIR ET (Holian), NSIR (Lewis, Stapleton), ILTAB (Johnson), IRD MOC (Gott). Notified DHS SWO, DHS NICC, FEMA, and Nuclear SSA via email.
|ENS 51270||27 July 2015 18:01:00||Fort Calhoun||NRC Region 4||On July 8, 2015, Fort Calhoun Station was in Mode 1, 100% when personnel identified an increase in the Reactor Coolant System unidentified leakage rate. As a result, personnel performed a containment entry and identified the source coming from the Reactor Coolant Pump 3A seal area. Based on this observation, a monitoring plan was established and on July 20, 2015 the leak rate exceeded the pre-establish leak limit and operators manually shutdown the reactor. On July 22, 2015, at approximately 1330 CDT, personnel identified the source of the seal leak as a crack on the middle seal inlet line, which is part of the reactor coolant system boundary. Maintenance personnel have since repaired the seal line and it has passed post-maintenance testing. The 8-hour verbal report is being made post event due to additional review of the leakage condition identifying the leakage constituted a degraded condition due to be material defects in the primary coolant system. The leak rate was between 1 and 2 gpm. The licensee notified the NRC Resident Inspector.|
|ENS 51131||5 June 2015 19:22:00||Fort Calhoun||NRC Region 4|
The following information was provided via email and telephone. Fort Calhoun Station is currently completing a scheduled refueling outage. On June 5, 2015 at 1330 during performance of surveillance testing on the auxiliary feed water system, (Hydraulic Control Valve) HCV-1107A, Steam Generator RC-2A Auxiliary Feedwater Inlet Valve, did not open when given an open signal. HCV-1107A has been declared inoperable. HCV-1107A is required to open to meet the decay heat removal safety function for Steam Generator A. Fort Calhoun Station is in Mode 3 (Reactor Coolant System temperature is greater than 515 degrees Fahrenheit and not critical). With HCV-1107A inoperable and unable to feed the A steam generator both auxiliary feedwater trains are considered inoperable. HCV-1107A is inside the Containment Building. Fort Calhoun Station Technical Specifications 2.5(1)D. requires: With both AFW trains inoperable, then initiate actions to restore one AFW train to OPERABLE status immediately. Technical Specification (TS) 2.0.1 and all TS actions requiring MODE changes are suspended until one AFW train is restored to OPERABLE status. Fort Calhoun Station is evaluating the best approach to repairing HCV-1107A. The Resident Inspector has been notified
Fort Calhoun Station has determined plant cooldown required to perform repairs. Plant cooldown in progress. The licensee will notify the NRC Resident Inspector. Notified R4DO (Whitten)
|ENS 50945||1 April 2015 18:53:00||Fort Calhoun||NRC Region 4||At 1210 CDT the transformer supplying power to the Emergency Operating Facility (EOF) stopped working due to the failure of a capacitor bank. The EOF is located adjacent to OPPD's (Omaha Public Power District) North Omaha facility, approximately 17 miles south of Fort Calhoun Station. The event caused a small grass fire which was quickly extinguished. The local fire department was called. The backup emergency diesel generator for the EOF started and supplied power to the facility, as designed. With the EOF diesel operating, the facility is able to function as required during emergency conditions. At 1440 CDT the EOF emergency diesel generator stopped running. At 1545 CDT the Conference Operations (COP) network phone system failed. The COP network is the primary emergency notification system between OPPD, state and county agencies. It is used to provide initial and updated notifications and for general information flow between these agencies. Alternate means of communication have been established (commercial lines) and a dedicated communicator is stationed in the control room to ensure that we can facilitate communication should the need arise. Power to the EOF was restored at 1713 CDT. At time 1720 CDT the COP tested as normal. The licensee notified the NRC Resident Inspector.|
|ENS 50800||10 February 2015 01:25:00||Fort Calhoun||NRC Region 4|
On October 14, 2013 a calculation for the containment internal structural analysis was revised and accepted by the station. This calculation limited the Safety injection tank level to 74%. On October 16, 2013 Safety injection tank level was raised to 100% for approximately 13 hours in preparations for plant start-up. While the plant was safely in a cold shutdown condition, this represents a reportable unanalyzed condition. This issue is of a historical nature and does not question the current operability of any plant systems or structures. This was self identified during a Fort Calhoun calculation review. The licensee notified the NRC Resident Inspector.
Following review of the reported event, attendant calculations and associated documentation, engineering personnel determined that the condition described in event notification EN50800 did not place the plant in an unanalyzed condition. Revision 1 of a calculation for the containment internal structural analysis demonstrated that when the safety injection tanks 'B' and 'D' are 100% filled in an outage condition, approximately a 10% safety margin is maintained. This revision was the calculation of record at the time the safety injection tank levels were raised above 74%, in October, 2013. Revision 2 of the calculation was completed to remove excess conservatism and to provide a closer representation of available margin. In addition, margin was also improved by limiting tank level to 74%. However, improving margin by limiting tank level to 74% does not result in an unanalyzed condition when tank level is 100%, as adequate margin remains. Therefore this event is being retracted. The licensee will notify the NRC Resident Inspector. Notified the R4DO (Okeefe).
|ENS 50688||17 December 2014 12:56:00||Fort Calhoun||NRC Region 4||At 1014 (CST) on 12/17/2014, the reactor automatically tripped due to loss of load on RPS (Reactor Protection System). Preliminary information indicates turbine-generator trip caused an uncomplicated reactor trip . All safety functions are met. Currently maintaining Mode 3, Hot Shutdown. At time of trip, non-safety related house transformers, T1A1 and T1A2 became inoperable as expected due to generator trip. Entered Technical Specification 2.7 (2)a, 72 hr LCO (for the inoperable T1A1 and T1A2 transformers). All control rods fully inserted. All busses are energized via offsite power. Decay heat is being released via AFW and the condenser bypass valves. The unit is stable in Mode 3. Cause of the loss of load is being investigated. The NRC Resident Inspector has been informed.|
|ENS 50214||20 June 2014 00:29:00||Fort Calhoun||NRC Region 4|
The National Weather Service predicts that the Missouri River level at Fort Calhoun Station will exceed 1004 feet above mean sea level on 6/20/14 at approximately 2300 CDT. Fort Calhoun Station will begin a ramp down in power to satisfy technical specification 2.16 which states, 'When the Missouri River level reaches elevation 1004 feet mean sea level, the reactor shall be in a HOT SHUTDOWN condition (Mode 3) and in Cold Shutdown (Mode 4) within 36 hours following entry into Hot Shutdown.' The river level is currently 998 feet 3 inches and rising approximately 0.5 inches per hour. At time 0001 CDT 6/20/14 Fort Calhoun station will initiate a plant shutdown to Hot Standby and will proceed to a Cold Shutdown condition within 36 hours following entry into Hot Shutdown, as required. The licensee notified the NRC Resident Inspector.
EN 50214 is being retracted. At 2300 (CDT) on 6/21/14, actual Missouri River level at Fort Calhoun Station peaked at 1001' 2" mean sea level (msl) and did not reach TS 2.16 (1) shutdown criteria of 1004' msl. Based on current Army Corps of Engineers and National Weather Service published Missouri River levels, the river upstream of Fort Calhoun Station has peaked and is trending down following the recent storms. River level is predicted to continue trending downward to normal summer navigation season levels. Plans to shutdown have been terminated. Fort Calhoun Station will continue to monitor weather and river levels. Current reactor power is 66% and Fort Calhoun Station is raising power to 100%. The lowest reactor power achieved was 30 percent at 1200 CDT on 06/20/2014. The licensee notified the NRC Resident Inspector. Notified R4DO (Hay)
|ENS 50038||15 April 2014 19:16:00||Fort Calhoun||NRC Region 4|
At 1505 CDT the 'A' control room air conditioner (VA-46A) trouble alarm annunciated in the control room. The unit was confirmed to be not functioning properly and was declared inoperable at time 1515 (CDT). The 'B' control room air conditioner (VA-46B) was previously declared inoperable due to maintenance. With both control room air conditioners inoperable the plant entered technical specification 2.0.1, a 6 hour shutdown action statement. Repairs to the 'B' had been previously planned and are in progress to allow the unit to be returned to service as soon as possible. Troubleshooting and subsequent repairs to the 'A' unit are in progress. At 1812 (CDT), the station commenced a shutdown to comply with the required action statement. The NRC Resident Inspector has been informed.
At time 2050 (CDT), VA-46A was declared operable based on installation of an emergency temporary modification. TS 2.0.1 has been exited. Shutdown has been secured and FCS is stable at a nominal 33% power. The licensee notified the NRC Resident Inspector. Notified the R4DO (Gaddy).
|ENS 49926||17 March 2014 15:55:00||Fort Calhoun||NRC Region 4||Ft. Calhoun station automatically tripped due to a loss of turbine load. The turbine tripped due to loss of stator cooling water. Maintenance was in progress on the stator cooling system when inventory was lost and low pump discharge pressure caused an automatic turbine trip and reactor trip. All systems operated as expected. Ft. Calhoun station is shutdown and stable in mode 3 at this time. All control rods fully inserted into the core and decay heat is being removed using the normal condenser steam dump system. The licensee has notified the NRC Resident Inspector.|
|ENS 49829||14 February 2014 14:00:00||Fort Calhoun||NRC Region 4||A non-licensed employee supervisor had a confirmed positive for marijuana during a random fitness-for-duty test. The employee's access to the plant has been terminated. The licensee informed the NRC Resident Inspector.|
|ENS 49717||12 January 2014 06:44:00||Fort Calhoun||NRC Region 4|
After achieving criticality a deviation between control rods was observed by plant personnel. When attempting to level the control rods, one rod could not insert to the level of the rest of the group. A manual reactor trip was initiated by the operating crew. All tripable control rods fully inserted into the core. The trip was uncomplicated and the licensee is investigating the cause of the control rod position deviation. The licensee has notified the NRC Resident Inspector.
Report was updated to indicate 8-hour reportable criteria for Valid Specified System Actuation (Reactor Protection System). The licensee will notify the NRC Resident Inspector. Notified the R4DO (Kellar).
|ENS 49710||10 January 2014 06:39:00||Fort Calhoun||NRC Region 4|
During an engineering walk down inside containment a minor leak from a pipe fitting was discovered on the primary sampling piping connected to penetration M-45. There was previously identified minor leakage from a fitting on this same penetration outside of containment in the auxiliary building. The containment isolation valves are currently tagged closed. The licensee notified the NRC Resident Inspector.
Additional testing was performed on penetration M-45 which determined that the penetration met the required leakage limits. Therefore this issue does not represent a degraded condition for the containment and is not reportable. The previous notification is being retracted. The licensee has notified the NRC Resident Inspector. Notified the R4DO (Kellar).
|ENS 49704||9 January 2014 06:42:00||Fort Calhoun||NRC Region 4|
At 0315 CST T.S. 2.0.1 was entered for all four Raw Water pumps being declared inoperable. The pumps were declared inoperable due to inability to close one of the sluice gates. There are six sluice gates and one is not functional. At 0518 the technical specification required shutdown commenced. The licensee notified the NRC Resident Inspector.
At 0900 CST 1/9/14 Fort Calhoun Station Unit 1 was manually tripped and entered Mode 3. Reactor Coolant System (RCS) cooldown to less than 300 deg F was commenced at time 1030 CST 1/9/14. The RCS temperature was less than 300 deg F at time 1433 CST. A press release has been issued. The licensee informed the NRC Resident Inspector. Notified R4DO (Hagar)
|ENS 49703||9 January 2014 06:42:00||Fort Calhoun||NRC Region 4||At 2230 CST on 1/8/14 during operator rounds it was self identified there was a block of ice formed on the shaft and top of one of the intake structure sluice gates. This has bent the sluice gate operating shaft. At 0315 CST on 1/9/14 it was verified this gate could not be closed. There are six intake sluice gates that are required to be able to close to act as flood barriers. The other 5 sluice gates are not affected by this condition. The licensee informed the NRC Resident Inspector.|
|ENS 49478||28 October 2013 18:02:00||Fort Calhoun||NRC Region 4||A review of industry operating experience regarding the impact of unfused direct current (DC) ammeter circuits in the control room has determined that the condition described below applies to Fort Calhoun Nuclear Station. This could result in an unanalyzed condition with respect to 10 CFR 50 Appendix R analysis requirements. The control room ampere indications for the Class 1E batteries and their chargers do not include over-current protection to limit fault current. In a postulated event, a fire in the control room could cause one of the ammeter wires to hot-short to the ground plane. Simultaneously, the event could cause another DC wire from the opposite polarity on the same battery to hot-short to the ground plane. This would cause a ground-loop through unprotected ammeter wiring. Since this circuit is not protected (not fused), this event could result in excessive current flow in the ammeter wiring to the point of causing a secondary fire in the associated raceway system. This could potentially cause the loss of the ability to conduct a safe shutdown as required by 10CFR50 Appendix R. This condition is being reported in accordance with 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition that significantly degrades plant safety. Compensatory measures (fire watches) have been implemented for affected areas of the plant. The NRC Resident Inspector has been notified.|
|ENS 49452||18 October 2013 19:38:00||Fort Calhoun||NRC Region 4||A postulated High Energy Line Break (HELB) between the Letdown Heat Exchanger and its containment penetration has been identified in the Fort Calhoun Station calculation FC07885, Rev. 0, Stress Analysis of Small Bore Piping on Isometric CH-4106 High Energy Line Break Assessment. Based on this, there is a potential for a HELB on the inlet of the Letdown Heat Exchanger that may adversely impact the upstream piping and the outboard containment isolation valve. Assuming a single failure of the inboard isolation, this condition has the potential to degrade a principal safety barrier by bypassing the containment building. The licensee has notified the NRC Resident Inspector.|
|ENS 49378||23 September 2013 18:37:00||Fort Calhoun||NRC Region 4||At 1340 CDT, on 09/23/2013, as part of a vendor analysis for the high energy line break reconstitution project, it was determined that Room 81 and 82 epoxy floor coatings do not meet the design basis requirements for a high energy line break barrier. This is an unanalyzed condition based on 10 CFR 50.72(b)(3) as loss of the floor coating could affect multiple redundant trains of safety-related equipment during a design basis event. The plant is currently in a cold shutdown condition. The licensee has notified the NRC Resident Inspector.|
|ENS 49324||5 September 2013 17:31:00||Fort Calhoun||NRC Region 4|
Current design basis calculations indicate the Low Pressure Safety Injection (LPSI) pumps could potentially operate in a run-out condition under certain worst case design basis conditions. The LPSI pumps could operate in a run-out condition beyond the analyzed time by 20 minutes. Current design basis calculation assumes LPSI Pump would be shutdown by (the) RAS (Recirculation Actuation Signal) in less than one hour, however due to past changes to Containment Spray Pump Start Logic, the time was lengthened to 80 minutes which is beyond the one hour analyzed. This represents a reportable unanalyzed condition. The licensee notified the NRC Resident Inspector.
Fort Calhoun completed additional analysis which verified that the LPSI pumps will not go into run-out as previously reported. Therefore Fort Calhoun is withdrawing the event notification. The licensee will notify the NRC Resident Inspector. Notified R4DO (Drake).
|ENS 49241||6 August 2013 08:48:00||Fort Calhoun||NRC Region 4|
Fort Calhoun Station entered a notification of unusual event due to high wind speeds at the site of 90.2 mph during a severe thunderstorm. IC (Initiating Condition) HU1 EAL2. Wind speeds have reduced to 25 mph sustained. The licensee has offsite power available and is in progress of conducting plant walkdowns. The thunderstorm has passed and sustained winds are 25 mph. The licensee has notified the NRC Resident Inspector, the State, and local governments.
At 0828 CDT Fort Calhoun Station terminated from the notification of unusual event. There was no damage to plant equipment or structures from the storm. Sustained winds are 15 mph. The licensee has notified the NRC Resident Inspector, the State, and local governments. Notified R4DO (Vasquez), NRR EO (Chernoff), IRD MOC (Kozal), DHS SWO, FEMA and DHS NICC.
|ENS 49119||14 June 2013 18:28:00||Fort Calhoun||NRC Region 4||While revising calculations for the station analyses for potential high-energy line breaks outside of containment, the station determined that the conditions required to validate the exclusion from analyzing for a break in some small-bore (1- to 4-inch diameter) piping could not be validated. The piping is contained within the station's auxiliary building. In the unlikely event of a break of one of these lines during power operations, the plant may not have been able to respond as expected. The plant is currently in cold shutdown, with the fuel removed from the core. The licensee notified the NRC Resident Inspector.|
|ENS 49112||13 June 2013 16:55:00||Fort Calhoun||NRC Region 4||The station is reporting an unanalyzed condition involving the steam driven auxiliary feedwater pump. A postulated high energy line break in the room containing the pump could result in steam communicating with equipment in the safety related switchgear and battery rooms which are immediately above the room. The plant is currently in cold shutdown with the fuel removed from the core. The licensee stated that in the event of a postulated high energy line break, steam could possibly enter the switchgear and battery rooms via a stairwell and ventilation ductwork. The licensee notified the NRC Resident Inspector.|
|ENS 49056||21 May 2013 22:15:00||Fort Calhoun||NRC Region 4||A non-licensed, contract supervisory employee failed a random fitness-for-duty test. The employee's access to the plant has been revoked. The licensee informed the NRC Resident Inspector.|
|ENS 49050||17 May 2013 17:28:00||Fort Calhoun||NRC Region 4|
It has been determined that some instrument racks in the Containment and Auxiliary buildings do not meet their design basis capacity due to inadequate embedment depth of the seismic anchors. Assumptions made about embedment depth for a previous event were determined to be incorrect; therefore, the design basis capacity cannot be assured. This report is being made under 10 CFR 50.72(b)(3)(ii)(B), 'Unanalyzed condition'. The licensee has notified the NRC Resident Inspector.
Additional evaluation has determined that the instrument racks are adequately anchored. Therefore, this event is not reportable. The licensee notified the NRC Resident Inspector. Notified the R4DO (Gepford).
|ENS 49027||13 May 2013 11:22:00||Fort Calhoun||NRC Region 4|
Planned intermittent outages of all FCS sirens will occur the week of 5/13/13-5/17/13 due to scheduled upgrades to the radio system. Based on the planned maintenance, all sirens for the Alert Notification System within the Emergency Planning Zone (EPZ) will be nonfunctional for various amounts of time. Prior notifications and coordination with Local Law Enforcement will be completed with compensatory measures established prior to work each day to support notification of the public in case of an actual emergency during the scheduled maintenance. Updates will be made to the NRC on 5/13/13 when the work starts, and upon completion of the work not to exceed 5/17/13. Work is currently scheduled to be complete 5/17/13. Also, contingencies have been established to back out if required in support of the plant or Law Enforcement activities. Work is scheduled to commence today, 5/13/13, at 10:10 AM. 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 notified the NRC Resident Inspector.
The work was completed on 5/16/2013 at 1700 CDT. The licensee notified the NRC Resident Inspector. Notified the R4DO (Walker).
|ENS 48994||3 May 2013 06:20:00||Fort Calhoun||NRC Region 4|
A planned outage of all FCS (Ft. Calhoun Station) sirens will occur today at 0530 CDT to transfer in-service zone controllers. During the planned maintenance, all sirens for the Alert Notification System within the Emergency Planning Zone (EPZ) are nonfunctional. Prior notifications and coordination with Local Law Enforcement have been completed with compensatory measures established to support notification of the public in case of an actual emergency during the scheduled maintenance. The licensee has notified the NRC Resident Inspector, Washington, Harrison, and Pottawattamie counties.
The maintenance has been completed and the EPZ sirens have been returned to service. Local Law Enforcement has been notified that the scheduled maintenance is complete and the primary method of alerting the public with sirens is restored. The licensee has notified the NRC Resident Inspector. Notified R4DO (Haire).
|ENS 48806||4 March 2013 18:32:00||Fort Calhoun||NRC Region 4||It has been determined that the mechanical seals used in two Low Pressure Safety Injection Pumps and three Containment Spray Pumps are made of a material that may not maintain the designed integrity of the systems under certain accident conditions. These seals have been installed since original plant construction. This issue was discovered by plant personnel while researching requirements for the replacement parts during scheduled outage activities. The licensee notified the NRC Resident Inspector.|
|ENS 48792||28 February 2013 15:34:00||Fort Calhoun||NRC Region 4|
Per 10 CFR 26.719 section (c)(2) the Omaha Public Power District (OPPD) is making this notification of an apparent false positive error that has occurred on a blind performance test sample submitted to the Health and Human Services (HHS)-certified laboratory used for drug testing. On February 27, 2013, OPPD was notified that two positive drug samples that were part of a blind performance test package provided by Professional Toxicology and submitted to Clinical Reference Laboratory tested negative. Currently Professional Toxicology indicates that the two positive samples were provided with the NRC required positive levels for the drug. OPPD will investigate the issue and report to the NRC as required by part 26.719(c)(1). Professional Toxicology and Clinical Reference Laboratory are contracted by OPPD as required by NRC regulations to provide fitness for duty services. The licensee notified the NRC Resident Inspector.
Additional investigation has determined that the samples submitted by Professional Toxicology did not contain the required levels of the drug being tested. The analysis performed by Clinical Reference Laboratory was correct. There was not a reportable condition per 10 CFR 26.719. Therefore, this report is being retracted. The licensee will notify the NRC Resident Inspector. Notified the R4DO (Powers).
|ENS 48787||27 February 2013 00:55:00||Fort Calhoun||NRC Region 4||During a follow-up review of off-site testing of a sample of General Electric model HFA relays, it was discovered that some of these relays did not pass testing for full qualification in their as-found condition. Additional torquing of the relay backing plate mounting screws was required to fully meet the required qualification. Further investigation into the as-found condition of these relays installed in the plant continues at this time. The relays in question are installed in Engineered Safeguards Features, Auxiliary Feed Water, and 4160 volt systems and are used in protective and actuation functions. The licensee has notified the NRC Resident Inspector.|
|ENS 48781||25 February 2013 16:01:00||Fort Calhoun||NRC Region 4||During a review of the plant inverters, it has been determined that the inverters may not have been operable. The inverters were replaced during the 2008 refueling outage. It appears that either the modification did not recognize that the diesel frequency range is wider than the new inverters, or did not recognize its consequence. Consequently, when the diesel is supplying power to the buses and loads are being sequenced onto the bus, the bus frequency exceeds the inverter frequency range. This causes inverter voltage transients. Operation of the inverters has been modified to improve plant reliability. This issue was discovered during scheduled plant testing of the electrical system. The licensee informed the NRC Resident Inspector.|
|ENS 48730||7 February 2013 18:21:00||Fort Calhoun||NRC Region 4||Current design basis calculations indicate the high pressure safety injection (HPSI) pumps could potentially operate in a run-out condition under certain worst case design basis conditions. The calculated flow is beyond the pump curves. The HPSI pumps could operate in a run-out condition for an extended period following a design basis accident. The pump vendor indicates that long term operation in this condition could not be supported due to accelerated wear of pump internal components. This represents a reportable unanalyzed condition. The NRC Resident Inspector has been notified.|
|ENS 48705||29 January 2013 10:10:00||Fort Calhoun||NRC Region 4|
A planned outage of all Fort Calhoun Station sirens is to occur at 0900 CST today to replace router power supplies. Based on the planned maintenance, all sirens for the Alert Notification System within the Emergency Planning Zone (EPZ) will be nonfunctional. Prior notifications and coordination with Local Law Enforcement have been completed with compensatory measures established to support notification of the public in case of an actual emergency during the scheduled maintenance. The planned maintenance is expected to take three hours with a projected completion time of 1200 CST. Contingencies have been established with the maintenance to back out if required in support of Law Enforcement activities. This is being reported per 10 CFR 50.72(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 and local authorities.
At 1159 CST, maintenance was completed with all sirens restored to functional status. Local Law Enforcement has been notified and relaxed required compensatory actions. The licensee will notify the NRC Resident Inspector. Notified R4DO (Walker).
|ENS 48668||11 January 2013 17:12:00||Fort Calhoun||NRC Region 4||During a random screening, a non-licensed contract supervisor tested positive for a controlled substance. The individual's unescorted access has been terminated. The Licensee has notified the NRC Resident Inspector.|
|ENS 48628||27 December 2012 15:46:00||Fort Calhoun||NRC Region 4|
Fort Calhoun Station (FCS) will be implementing a scheduled modification to renovate and upgrade the interior configuration of the site's Operational Support Center (OSC). The OSC is located within the Technical Support Center (TSC). The TSC will remain fully operable. Due to the construction, beginning on December 27, 2012 with a planned completion date of February 27, 2013, the OSC will be inoperable. An alternate OSC has been established on-site and is fully operable. The licensee notified the NRC Resident Inspector.
This is an update to Event Notification 48628, dated December 27, 2012. On March 8th, 2013, Fort Calhoun Station (FCS) will be entering a new phase of scheduled modifications to renovate and alter the interior configuration of its Technical Support Center (TSC). The TSC ventilation system will not be functional during this phase of modification. Combined with renovations, the primary TSC and OSC will be inoperable. An alternate OSC and TSC have been established. If the Emergency Response Organization is activated the alternate emergency facilities will be available for emergency responders per existing Emergency Plan procedures. The project is scheduled to be completed April 12, 2013. An update to this report will be provided when the TSC renovation is complete. The licensee informed the NRC Resident Inspector. Notified R4DO (Werner).
This is an update to Event Notification 48628, dated December 27, 2012. As of April 12th, 2013 Fort Calhoun Station has completed modifications to the Technical Support Center (TSC) and Operations Support Center (OSC). The TSC ventilation system has been proved functional through required testing. The primary TSC/OSC is now fully operational. The licensee notified the NRC Resident Inspector. Notified R4DO (Deese).
|ENS 48551||2 December 2012 17:28:00||Fort Calhoun||NRC Region 4||The raw water pumps (AC-10A/B/C/D) base plate support anchors were discovered by Fort Calhoun Station personnel to have inadequate embedment to support existing analysis. Plant drawing specify a j-bolt type of anchor with a required 16 inch embedment. Actual plant configuration was found to be a j-bolt type anchor with a 9 inch embedment. Plant design analysis requirements are not being met for the existing configuration. Existing analysis requires a minimum embedment of 60 inch for a j-bolt type anchor. There are a total of 4 anchors for each raw water pump, totaling 16 anchors. The as found condition renders all four raw water pumps inoperable. In the current plant Mode 5 (De-fueled), Shutdown Condition, the raw water pumps are considered available per the station's Shutdown Operations Protection Plan. Raw water pumps AC-10B and AC - 10D are in service providing cooling to the Component Cooling Water System. The core is offloaded and the Component Cooling Water System is maintaining Spent Fuel Pool temperature. The licensee notified the NRC Resident Inspector.|
|ENS 48485||7 November 2012 09:39:00||Fort Calhoun||NRC Region 4|
A planned outage of all FCS (Fort Calhoun Station) sirens is to occur at 0900 CST today to replace required router power supplies. Based on the planned maintenance, all sirens for the Alert Notification System within the Emergency Planning Zone (EPZ) will be nonfunctional. Prior notifications and coordination with Local Law Enforcement have been completed with compensatory measures established to support notification of the public in case of an actual emergency during the scheduled maintenance. The planned maintenance is expected to take three hours with a projected completion time of 1200 CST. Also, contingencies have been established with the maintenance to back out if required in support of Law Enforcement activities. 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 notified the NRC Resident Inspector and local counties.
At 1129 CST, maintenance was completed with all sirens restored to functional status. Local Law Enforcement has been notified and relaxed required compensatory actions. NRC Resident informed. Notified R4DO (Farnholtz).
|ENS 48313||17 September 2012 15:23:00||Fort Calhoun||NRC Region 4||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 48148||1 August 2012 13:24:00||Fort Calhoun||NRC Region 4||At 0327 CDT, a call was received from the NRC Operations Center for Emergency Notification System (ENS) phone status check on the commercial phone line. The ENS phone system had no incoming rings, nor a dial-tone. The NRC Headquarters Operations Officer (HOO) was to submit a trouble ticket. At 0949 CDT, Emergency Planning personnel were working with Verizon Communications to determine the cause of the loss of the ENS phone. Verizon had isolated the problem to the American Broadband network and was working to resolve the problem. At 1010 CDT, Emergency Planning personnel identified that the Health Physics Network (HPN) line, the Protective Measures Counterpart (PMC) and Reactor Safety Counterpart (RSC) lines with the NRC had also been lost. The Conference Operations Network (COP) and all other commercial phone lines were functional and remained available. All areas were reachable by commercial phone lines. At 1022 CDT, the FCS Control Room was informed by Emergency Planning personnel of the communication means that were lost. The Emergency Plan per EPIP-OSC-1 was reviewed and verified no initiating conditions applied. At 1034 CDT, Emergency Planning personnel verified the communications problem with ENS, HPN, the Protective Measures Counterpart and Reactor Safety Counterpart lines was limited to the Fort Calhoun site. The Emergency Operations Facility (EOF) was not affected. At 1054 CDT, the ENS phone was restored to the FCS Control Room. This was verified by FCS placing a call to the NRC Operations Center. The NRC Operations Center then returned the call. All communications were satisfactorily restored. At 1132 CDT, the Protective Measures Counterpart line was restored. At 1142 CDT, the HPN and Reactor Safety Counterpart lines were restored. 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 notified the NRC Resident Inspector.|
|ENS 48111||17 July 2012 15:04:00||Fort Calhoun||NRC Region 4||Results of a thermal fatigue analysis on the Chemical and Volume Control System (CVCS) charging line concluded that the socket weld fittings above the RCS piping cannot be qualified. As an interim action, shut down cooling purification has been secured and charging has been isolated to the RCS. The plant is shutdown and in Mode 5 with the reactor vessel head removed, so RCS is not intact and not required to be for current plant conditions. This report is being made in accordance with 10CFR50.72(b)(3)(ii)(A) for a degraded condition. The licensee has notified the NRC Resident Inspector.|