Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 51439 | 2 October 2015 14:05:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Notification of Unusual Event | 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 49241 | 6 August 2013 12:22:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to High Winds | 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 47051 | 15 July 2011 00:13:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Suspected Introduction of Contraband Into the Protected Area | The licensee declared an Unusual Event due to indications that potentially dangerous contraband had been introduced into the protected area. After further investigation, the licensee determined that the indication of contraband was due to incorrect interpretation of screening equipment imaging. The licensee exited its Unusual Event declaration at 1942 CDT. The licensee continues to investigate the circumstances leading to this event declaration. The licensee notified State and local authorities and will notify the NRC Resident Inspector | ||
| ENS 46932 | 7 June 2011 14:40:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Fire in the West Switchgear Room | 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. | Emergency Diesel Generator Shutdown Cooling | |
| ENS 46929 | 6 June 2011 13:00:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Unusual Event Declared Due to River Level | At 0800 CDT a Notification of Unusual Event (HU 1, EAL 5) for operating mode less than 210 degrees F is being declared for a river level expected to exceed a 1004' MSL (Mean Sea Level), but less than or equal to 1009' MSL elevation. Currently Abnormal Operating Procedure AOP-1 is being implemented for high river level, as well as, PE-RR-AE-1001 for Flood Barrier and Sandbag Staging and Installation. 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. Applicable governmental agencies have been notified per plant procedures. No press release is expected at this time. * * * UPDATE FROM ERICK MATZKE TO PETE SNYDER AT 1121 EDT ON 6/6/2011 * * * During the emergency notification the automated paging function did not cause the pagers to actuate. The issue is being investigated." A notification for 10 CFR 50.72(b)(3)(xiii) be added to the header. Notified R4DO (Whitten).
OPPD will be making a press release for this event at about 1220 CDT. The licensee will be notifying the NRC Resident Inspector. Notified R4DO (Whitten) and HQPAO (Brenner).
At 1342 CDT on 08/29/11, FCS (Fort Calhoun Station) terminated the Notification of Unusual Event for flooding. Missouri river level receded to less than entry criteria and is currently 1003.56 ft MSL. The licensee has notified the State of Nebraska, Harrison County, Washington County, and Pottawattamie County of the termination. Notified R4DO (Proulx), IRD (Marshall), NRR (Thorp), DHS (Rickerson), and FEMA (Dennis). | ||
| ENS 46490 | 19 December 2010 06:08:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(xiii), Loss of Emergency Preparedness | Quickly Concluded Notice of Unusual Event Due to a Loss of Communications | At 2355 CST, on 12/18/2010, the Control Room was notified by security of the inability of offsite personnel to call into the plant. (At) 0008 CST, on 12/19/2010, the control room verified that the ENS Phone, Conference Operation Network (COP), Security Building, Training Center, and Blair Phone Lines were not functional. At 0011 CST, a Notice of Unusual Event (NOUE) was declared per IC SU6 EAL 2. This also meets the criteria for a Major Loss of Communications Capability under 10 CFR 50.72(b)(3)(xiii). At 0028 CST, the control room was notified by security that Huntel Communications was attempting to correct the communications issue. At 0030 CST, the COP phone was restored. At 0046 CST, the ENS phone was verified to be functional. At 0050 (CST), the criteria to exit the NOUE (was met) and the event was terminated. At 0059 (CST), the NRC Senior Resident Inspector was notified. The state and local agencies were notified. The NRC Operations Center conducted a satisfactory test of the ENS line. | ||
| ENS 44851 | 13 February 2009 21:26:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(2)(i), Tech Spec Required Shutdown | Unusual Event - Engineering Analysis Requires Technical Specification Shutdown | On February 13, 2009 at 1526 CST, Fort Calhoun Station declared a Notification of Unusual Event (NOUE) based upon EAL 4.2 - Both Diesel Generators NOT Operable. The station has entered Technical Specification 2.0.1(1) requiring the Unit to be placed in at least HOT SHUTDOWN within 6 hours. The cause of the NOUE is a potential common mode failure of the diesel generators. Design Engineering has identified an unanalyzed condition in which a High Energy Line Break in Room 81, Main Steam Lines Containment Penetration Room, or an auxiliary steam leak in Room 82, Turbine Building Ventilation Room, can potentially result in water entering both diesel generator rooms through the floor of Room 82 located directly above the diesel rooms, Rooms 63 and 64. This condition presents a potential common mode failure of the diesel generators due to loss of diesel generator auxiliaries from a single failure. The possibility of water leaking into Rooms 63, 64 and the Switchgear rooms prompted this declaration. Compensatory measures to exit the NOUE will be to remove auxiliary steam from room 82 and blockading shut the door between rooms 81 and 82. These actions are expected to be completed within one to three hours. The licensee notified the NRC Resident Inspector.
At 1828 CST, Fort Calhoun Station exited the Notification of Unusual Event. Both Diesel Generators were declared operable based upon establishing compensatory measures. Diesel 2 was confirmed operable by running in accordance with approved procedures. Diesel 1 was successfully run on February 11, 2009 per a monthly surveillance tests. No additional water intrusion had occurred into the diesel 1 room since completion of the surveillance test. Compensatory measures to prevent water intrusion into Room 82 include isolating auxiliary steam to room 82 to eliminate a source of water to room 82, installing a temporary barrier at the door between rooms 81 and 82 to prevent water from flowing from room 81 to room 82, should an HELB occur in room 81, and to open the door between room 81 and the turbine building to allow water to flow out of room 81 so as not to flow into room 82. Technical Specification 2.0.1 has been exited as of time 1828 CST. The licensee will notify the NRC Resident Inspector. Notified the R4DO (Miller), IRD (McDermott, McMurtray), DHS (Doyle), and FEMA (Via).
This is a retraction (of the report made under 10 CFR 50.72(b)(3)(ii)(B) - Unanalyzed Condition) Fort Calhoun has performed a detailed evaluation of water intrusion through cracks in the floor of room 82 above the emergency diesel generators, as identified in part in the notification of 2/13/2009. This evaluation determined that no common mode failure mechanism existed and that the diesel generators were capable of performing their design safety functions. The licensee informed the Resident Inspector. Notified R4DO (Rick Deese). | Emergency Diesel Generator Main Steam Line | |
| ENS 43636 | 13 September 2007 10:01:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Notice of Unusual Event for a Hydrazine Spill in the Turbine Building | A Notification of an Unusual Event was declared at 06:01 EDT due to a chemical leak in the Turbine Building truck dock area near a roll-up door. The leak was discovered at 05:40 EDT coming from a line connecting two vertically stacked Hydrazine Metal chemical storage totes located inside a ventilated enclosure. The Hazmat Response Incident Team was formed to address the spill. Approximately 10 gallons is inside the enclosure berm. A small amount of liquid has leaked outside the enclosure berm but has been contained. Containment activities are in progress. Leak rate appears to be significantly less. Additional plant staff has been called in to support and are arriving on site at the time of this notification. The area has been roped off and plant announcements to warn personnel of this hazard have been made. (EAL-11.4, Plant Conditions Warrant Increased Awareness by Plant Staff) The licensee notified the NRC Resident Inspector, state and local government agencies. * * * UPDATE AT 0742 ON 9/13/07 FROM CHLADIL TO ROTTON * * * The licensee terminated the Notice of Unusual Event. The termination criteria was that the spill was stopped and the licensee has established limited personnel access restrictions to the turbine building truck bay and the service building elevator. The licensee is continuing to clean the area. The licensee notified the NRC Resident Inspector and will be notifying state and local government agencies. Notified R4DO (Shannon), NRR (Ross-Lee), IRD (Blount), DHS (Haselton) and FEMA (Laforty). | ||
| ENS 40194 | 23 September 2003 18:20:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event | While in Mode 5, refueling Shutdown with Core offload in progress a fuel assembly in the Spent Fuel Pool became ungrappled. The assembly is currently sitting on the top of the Spent Fuel pool racks resting against the Pool wall at approximately 15 degrees. There is no damage to the Fuel Assembly, evident by no change in area radiation dose rates. EAL 1.14, Plant Conditions Warrant Increased Awareness By Plant Staff or Government Authorities. An investigation has begun to determine the cause of the event and a team is being assembled to plan the fuel bundle recovery. The licensee notified the NRC Resident Inspector.
The licensee remains in a NOUE (Notice of Unusual Event) due to the ungrappled spent fuel assembly. The position of the spent fuel assembly remains the same as previously reported. No damage to the fuel assembly nor the spent fuel rack has been detected. No abnormal radiation readings have been observed. As a precaution, the licensee has suspended all fuel movement operations and evacuated the auxiliary and containment buildings. The licensee plans to stabilize the fuel assembly, attach a lifting tool, and place it into a permanent storage position in the spent fuel pool. Notified R4DO (Greg Pick)
At 12:42 CDT the fabricated stabilization device installation was completed and it is currently secured to two walls of the spent fuel pool. The plant will remain in a NOUE until the fuel assembly is lowered into a safe location in the spent fuel pool. A tool has been fabricated to grapple the fuel assembly and it will be moved with the Spent Fuel Pool Refueling Machine. The tool is currently being tested and weighed. All unnecessary personnel were moved from the Protected Area to the Administration and Training Buildings during the placement of the stabilization device. The NRC Resident Inspector was notified. Reg 4 RDO (Greg Pick) was notified
The licensee reported that the ungrappled spent fuel assembly was placed in a permanent storage position in the spent fuel pool at 1654 CDT. As a result of this action, the licensee terminated the Notice of Unusual Event (NOUE) condition at this time. Normal access to the facility protected area and radiation control area has been restored. Fuel movement operations remain suspended and a root cause investigation of this event is being conducted. The licensee notified the NRC Resident Inspector. NRC R4DO (Greg Pick), DIRO (Richard Wessman), NRR EO (Gene Imbro), FEMA (Ken Sweetser), DOE (Joe Stanbaugh), DHS (Sam Neglia) were notified by the Headquarters Operations Officer. | ||
| ENS 40165 | 17 September 2003 13:43:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Post Alert Emergency Declaration Based on Calculated Rcs Inventory Loss | The plant is currently in Mode 5 for a Refueling outage. Reactor Coolant System (RCS) level was being maintained just below the Reactor Vessel flange, 1012.33 feet, with Shutdown Cooling in service and Shutdown Cooling Purification in service. RCS temperature was 100F. At 0821 a lowering level was noted on the Control Room level indications LI-119 and LI-197. At 0824 Shutdown Cooling Purification was secured and the lowering level was stopped with an indicated RCS level 1010.33 feet. At 0843 it was determined that approximately 1350 gallons of RCS water was lost over the 3 minutes that the event lasted. It was determined that during that time conditions existed to enter EAL 1.4, RCS leak greater than 40 gpm. At no time was Shutdown Cooling lost and RCS temperature remained at 100F. At 0825 Abnormal Operating Procedure (AOP-19) was entered. Makeup to the RCS was initiated immediately and level was completely restored at 0842 with charging pumps secured. It has not been determined at this time where the inventory went. A walkdown of the Containment and Auxiliary Building has been completed. At this time the plant is stable with an RCS level on 1012.5 feet. The licensee is conducting an investigation and will provide an update to this report. The licensee informed both the State of NE and IA and the NRC Resident Inspector.
The licensee is retracting this report based on the following: On September 17, 2003, the Fort Calhoun Station notified the NRC that conditions had existed, for about 3 minutes, to make an alert notification. No alert was declared as the time the station was in the condition was such, a limited time. The condition that required the notification was a reactor coolant system (RCS) leak of >40 GPM. The event occurred as follows: At approximately 0821 on September 17, 2003, Operations noted decreasing level in the reactor vessel. This was indicated on both of the shutdown RCS level indicators. Due to the uncontrolled (indicated) reduction in RCS level, AOP-19 was entered. Within minutes, the indicated level had dropped from 1012' 6" to 1010' 3". Shutdown cooling purification was isolated. The two (2) charging pumps running for shutdown purification were left in operation. After a few minutes, the charging pump's 80 gpm flow caused the RCS level to stop dropping and RCS level began to rise. During and immediately following this event, numerous walkdowns of containment and the auxiliary building were performed that ensured there was no loss of water from the RCS. No coolant leakage was noted during the walkdowns. The cause of the level change was small pressure in the head making the indication read higher than actual. Disconnecting the HJTC clamp allowed a positive vent which caused indicated level to fall. When interviewing the craft performing the work on the HJTC, it was noted that when removing the clamp front a HJTC, the craft noticed a small amount of water bubbling on the HJTC and when an attempt was made to lift the HJTC hub, air was heard in the vicinity of the HJTC. Additionally the craft stated there was some resistance felt from the HTJC when attempting removal. The craft then contacted radiation protection to determine what personnel protection was required. On the second attempt to lift the hub, the craft heard air flow in the vicinity again. When the clamp was finally lifted there was little resistance. It is suspected that the air at the HJTC was due to a pressure differential between the vessel and the containment atmosphere. The higher pressure in the reactor vessel caused level indications to read higher than actual level by approximately 2 feet. When the HJTC flange opened, the change in pressure caused a redistribution of water levels in the RCS. This caused the indicated RCS level change. There was never a leak of RCS coolant outside of the RCS. Therefore, this event notification is being retracted. The licensee informed the NRC Resident Inspector. Notified R4DO(Gody). | Reactor Coolant System Shutdown Cooling |