Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 55691 | 6 January 2022 15:44:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to a Fire in the Aux Cable Vault | The following information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: On 01/06/22 at 1044 (EST), an Unusual Event was declared due to a Fire Detection Actuation in the Unit 1, auxiliary cable vault (EAL H.U 4.1). No fire was detected. Unit 1 and Unit 2 remain at 100 percent power. The Llcensee notified the NRC Resident Inspector, the state, and local authorities. Notified DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), and DHS Nuclear SSA (email).
At 1441 (EST), DC Cook Unit 1 terminated their notification of unusual event. The basis for termination was that the inspection identified no damage to cables or cable trays. The fire protection system is out of service for the auxiliary cable vault with compensatory measures in effect. The licensee has notified the state and local authorities and will notify the NRC Resident Inspector. Notified R3DO (Skokowski), IRD MOC (Grant), NRR EO (Felts), IR (Kennedy)(email), NRR (Veil)(email), R3 DRA (Shuaibi)(email), DHS SWO, FEMA Operations Center, CISA Central, FEMA NWC (email), DHS Nuclear SSA (email), and FEMA NRCC SASC (email). | ||
| ENS 54729 | 27 May 2020 13:12:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Inadvertent Actuation of Sirens | On 5/27/20 at approximately 0912 EDT, the Operations Shift Manager was made aware that the Berrien County Sheriff's Department (BCSD) inadvertently actuated the emergency sirens during a planned weekly test. BCSD notified Cook Nuclear Plant that an audible test was initiated instead of a silent test. All Emergency Notification sirens remain in service. No press release is planned by the licensee at this time. This notification is being made under 10 CFR 50.72(b)(2)(xi), Offsite Notification, as a four (4) hour report. The licensee has notified the NRC Resident Inspector. | ||
| ENS 54036 | 30 April 2019 00:29:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to a Spurious Actuation of an Emergency Siren | On 4/29/19, at approximately 2029 EDT, the Operations Shift Manager was made aware that the Berrien County Sheriff's Department (BCSD) had been notified of an Emergency Siren that had spuriously actuated. BCSD was notified by local residents. The affected siren has been disabled and it has been verified that all associated local areas still have coverage from other functional emergency sirens. The cause of the actuation is under investigation at this time. This notification is being made under 10 CFR 50.72(b)(2)(xi), Offsite Notification, as a four (4) hour report." The licensee has notified the NRC Resident Inspector. | ||
| ENS 52967 | 13 September 2017 04:47:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Due to Letdown Relief Valve Discharge to the Pressurizer Relief Tank | At 0047 EDT, the licensee declared a notification of unusual event under emergency action level (EAL) S8 due to actuation of the letdown relief valve which resulted in reactor coolant system leakage to the pressurizer relief tank exceeding 10 gpm. The plant was in mode 3 at the time making preparations to proceed to cold shutdown to support their refueling outage. Operators were in the process of reducing reactor coolant system letdown from 120 gpm to 45 gpm when the letdown system relief valve lifted. The relief discharged to the pressurizer relief tank at approximately 12 gpm. Operators isolated the letdown line which reduced the leakage to approximately 1 gpm. Plant staff is in the process of determining where the 1 gpm leakage is from and evaluating the basis for terminating the unusual event. Notified DHS SWO, FEMA Operations Center, DHS NICC, FEMA National Watch Center (email) and Nuclear SSA (email).
At 0800 EDT, the licensee terminated the notification of unusual event. The basis for termination was that the letdown line was isolated which reduced leakage to less than the EAL threshold of 10 gpm. The cause of the letdown relief lifting is still under investigation. The licensee has notified the NRC Resident Inspector and will be notifying the state of Michigan and Berrien County. The licensee has issued a press release to the media concerning this event. Notified R3DO (Riemer), IRD MOC (Stapleton), NRR (Miller), DHS SWO, DHS NICC, FEMA Ops Center, FEMA National Watch Center (email) and Nuclear SSA (email).
The condition reported in Event Notification #52967 pursuant to 10 CFR 50.72(a)(1)(i) has been evaluated, and determined not to have met the threshold for classification as an Unusual Event under Emergency Action Level (EAL) S-8 and is being retracted. During the events of 9/13/17, Control Room staff calculated Reactor Coolant System (RCS) leakage to the Pressurizer Relief Tank (PRT) through the Letdown Relief Valve to be greater than the EAL S-8 threshold of 10 gallons per minute. Subsequent review of trends associated with PRT level increase during the event determined that the RCS leakage to the PRT was less than 10 gallons per minute and therefore did not represent an Unusual Event under EAL S-8. The NRC Resident Inspector was notified of this retraction. Notified R3DO (Riemer). | Reactor Coolant System | |
| ENS 52649 | 30 March 2017 07:10:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Loss of All Control Room Annunciators | The Unit 1 DC Cook Nuclear Plant (CNP) Annunciator System failed on Thursday, March 30, 2017 at 0255 (EDT). The failure resulted in a complete loss of all alarm function of the Annunciator System in the Unit 1 Control Room. Unit 2 was unaffected by this failure. At 0310 (EDT), an Unusual Event (UE) was declared due to System Malfunction S-6, Loss of Alarms or Indication, due to an unplanned loss of safety system annunciators and/or indications in the Control Room for greater than 15 minutes. The Unit 1 PPC (Plant Process Computer) and ERDS (Emergency Response Data System) remain functional and available. This notification is being made in accordance with 10 CFR 50.72(a)(1)(i) due to the declaration of an Emergency Classification specified in the licensee's approved Emergency Plan. The licensee has notified the NRC Resident Inspector, the State and local agencies. Notified DHS SWO, FEMA Ops Center, DHS NICC. Notified FEMA National Watch and Nuclear SSA via E-mail.
Unit 1 DC Cook Nuclear Plant Annunciator System has been returned to functional. Unusual Event Classification was terminated at 0817 EDT on 3/30/17. The NRC Resident Inspector will be notified. Notified R3DO (Cameron), NRR EO (Miller), and IRD (Grant). Notified DHS SWO, FEMA Ops Center, DHS NICC. Notified FEMA National Watch and Nuclear SSA via E-mail. | ||
| ENS 52585 | 1 March 2017 18:03:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Notification of Offsite Agencies Due to Sulfuric Acid Leak within the D.C. Cook Protected Area | At 1303 EDT on March 1, 2017, DC Cook notified the State of Michigan of a sulfuric acid tank leaking over 1,000 gallons of acid into the tank's berm. The leak was identified at approximately 1000 EDT coming from a drain line flange. The berm is designed to contain over 15,000 gallons which is sufficient to collect the known capacity of the tank. Cleanup of the sulfuric acid from the berm is ongoing, with no release to the environment or nearby drains. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) due to notification of offsite agencies. The NRC Resident Inspector was notified. | ||
| ENS 52065 | 6 July 2016 04:38:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Manual Reactor Trip and Unusual Event Declaration Due to Steam Leak in Turbine Building | On July 6, 2016, at 0038 (EDT), DC Cook Unit 2 Reactor was manually tripped and at 0050 (EDT) an Unusual Event (N-7 'Unanticipated Explosion') Emergency Declaration was made due to steam leak and associated damage to the turbine building. In accordance with Emergency Plan procedures, notifications of Berrien County and State of Michigan were completed. The licensee has notified the NRC Senior Resident Inspector. The Unusual Event was terminated at 0207 (EDT). This notification is being made in accordance with 10 CFR 50.72 (a)(1)(i) due to declaration of an emergency class. Original notification to NRC made at 0100 EDT via ENS. This event is reportable under 10 CFR 50.72(b)(2)(iv)(B), Reactor Protection System (RPS) actuation and 10 CFR 50.72(b)(2)(xi) Offsite Notification, as a four (4) hour report, and under 10 CFR 50.72(b)(3)(iv)(A), specified system actuation of the Auxiliary Feedwater System, as an eight (8) hour report. The DC Cook NRC Resident Inspector has been notified. A press release is planned. Unit 2 is being supplied by offsite power. All control rods fully inserted. Decay heat is being removed via Steam Generator PORVs (Power Operated Relief Valve). Preliminary evaluation indicates all plant systems functioned normally following the reactor trip. DC Cook Unit 2 remains stable in Mode 3 while conducting the Post Trip Review. No radioactive release is in progress as a result of this event. Notified DHS SWO, FEMA Ops Center, DHS NICC. Notified FEMA National Watch and Nuclear SSA via email. | Steam Generator Reactor Protection System Auxiliary Feedwater Control Rod | |
| ENS 51859 | 8 April 2016 22:20:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Oil Leak in a Switchyard Transformer Oil System | At 1657 EDT on April 8, 2016, an oil leak developed from the station's switchyard transformer no. 4. Approximately 25,000 gallons of oil has leaked within the transformer's containment berm. At 1820 EDT on April 8, 2016, DC Cook environmental personnel determined that approximately 2000 gallons of oil had leaked outside of the containment berm onto the ground. None of the oil has made it to any nearby drains. Leak has stopped and cleanup is ongoing. D.C. Cook has notified the State of Michigan and local authorities. The NRC Resident Inspector was notified. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) due to notification of offsite agencies. | ||
| ENS 50822 | 13 February 2015 18:15:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification to Michigan Osha | At 1123 EST on 2/13/2015, an emergency medical report was received in both unit's Control Rooms that an individual was having a personal medical issue outside the protected area. Onsite Emergency Medical personnel were dispatched to the scene. Off-site medical assistance was immediately requested. CPR was administered and the individual was transferred by off-site medical ambulance service to a local hospital. The Operations Shift Manager received confirmation of a fatality at 1315 EST on 2/13/2015. Notification was made to the Michigan Occupational Safety and Health Administration (MIOSHA). Both Units remain at 100% power. This Event Notification is being made due to the fatality and notification to a government agency. The NRC Resident Inspector has been notified. The individual was at the workout facility when this incident occurred. | ||
| ENS 50697 | 20 December 2014 17:12:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Oil Leak from Main Turbine Lube Oil System | At 1212 EST on December 12, 2014, D.C. Cook notified the State of Michigan and local authorities of an oil leak from the Unit 2 Main Turbine Lube Oil Cooler to Lake Michigan. Approximately 2000 gallons have leaked into Lake Michigan since October 25, 2014. No visible oil or oil sheen is present on Lake Michigan or the shore line. The leak is currently isolated as of 1030 EST on December 20, 2014. Leak repairs will be made to the cooler prior to placing back in service. The NRC Resident Inspector was notified. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) due to notification of offsite agencies. Notified DOE, EPA, USDA, HHS, and FEMA.
The licensee issued a press release about this event this afternoon. Notified R3DO (Dickson). | Main Turbine | |
| ENS 50498 | 28 September 2014 12:30:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Inadvertent Activation of an Emergency Siren | On 9/28/14 at approximately 0830 EDT, the Operations Shift Manager was made aware that the Berrien County Sheriff's Department (BCSD) had been notified of an Emergency Siren that had actuated. BCSD was notified by local residents. BCSD reset the emergency siren and a local police officer verified the siren was no longer actuating. The cause of the actuation is under investigation at this time. The siren remains in service pending further investigation. There are a total of 70 sirens and all remain functional. This notification is being made under 10 CFR 50.72(b)(2)(xi), Offsite Notification, as a four (4) hour report. The licensee notified the NRC Resident Inspector. | ||
| ENS 50462 | 16 September 2014 19:19:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notifications and Press Release Regarding Onsite Fatality | At approximately 1420 (EDT) on September 16, 2014, a worker collapsed in an office building inside the protected area. Initial response by on-site responders found the person unresponsive. Subsequent response by off-site medical responders determined the person had died. Licensee was notified of fatality at 1519 (EDT). The fatality was due to an apparent personal medical issue and not work related. The individual was not contaminated. The individual was transported off-site via Medic One, a local ambulance. The NRC Senior Resident Inspector was notified. Plant operation was not impacted by the event. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) due to notification of offsite agencies. The Licensee plans to make a press release. The licensee also notified Michigan OSHA, and other local authorities. | ||
| ENS 50386 | 21 August 2014 06:10:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Suspected Fuel Oil Leak to the Environment | At 0210 EDT on August 21, 2014, D.C. Cook made notifications to the State of Michigan, local authorities and the National Response Center due to a suspected release of approximately 8,700 gallons of diesel fuel oil to the environment. The level in the buried fuel oil storage tank for the Train B Emergency Diesel Generator was found to be approximately 8,700 gallons less than measurements taken within the last 24 hours. The tank is located within the plant protected area. At this time the suspected fuel oil plume has not left the site. The NRC Resident Inspector was notified. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) and NUREG 1022 section 3.2.12, due to notification of offsite agencies.
An event investigation determined that no spill occurred. The discrepancy in level was due to maintenance activities that caused an error in level indication. No actual loss of inventory from the fuel oil storage tank occurred. Offsite agencies have been notified that this spill event is being retracted (to the State and Offsite agencies). The NRC Resident Inspector was notified. Notified the R3DO (Passehl). | Emergency Diesel Generator | |
| ENS 50188 | 11 June 2014 03:27:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to an Inadvertent Activation of an Emergency Siren | On 6/10/14 at approximately 2327 EDT, the Operations Shift Manager was made aware that the Berrien County Sheriffs Department (BCSD) had been notified of an Emergency Siren that had actuated. BCSD was notified by local residents. BCSD reset the emergency siren and a local police officer verified the siren was no longer actuating. The cause of the actuation is under investigation at this time. The siren remains in service pending further investigation. There are a total of 70 sirens and all remain functional. This notification is being made under 10 CFR 50.72(b)(2)(xi), Offsite Notification, as a four (4) hour report. The licensee has notified the NRC Resident Inspector. | ||
| ENS 49364 | 20 September 2013 02:30:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to an Inadvertent Activation of an Emergency Siren | On 9/19/13 at approximately 2230 EDT, Emergency Siren 602 inadvertently actuated. Berrien County Dispatch was notified by local residents at 2237 EDT. The cause of the actuation is under investigation but believed to be due to rain water intrusion. The siren was subsequently disconnected by a station technician to prevent further erroneous actuation. The siren remains out of service and is the only siren out of service within the 10 mile Emergency Planning Zone (EPZ). There are a total of 70 sirens. This notification is being made under 10 CFR 50.72(b)(2)(xi), Offsite Notification, as a four (4) hour report. The Operations Shift Manager was notified of the actuation on 9/20/13 at 0340 EDT. The licensee has notified the NRC Resident Inspector. | ||
| ENS 48945 | 19 April 2013 03:12:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Inadvertent Activation of an Emergency Siren | On 4/18/13 at 2312 EDT, Emergency Siren 955 inadvertently actuated for approximately 5 minutes. The cause of the actuation is under investigation but believed to be due to rain water intrusion. The siren stopped on its own, and was subsequently disconnected by the siren vendor to prevent further erroneous actuation. The siren remains out service and is the only siren out of service within the 10 mile Emergency Planning Zone (EPZ). There are a total of 70 sirens. The siren is located in a state park not currently inhabited by campers; due to the siren location and time of activation the impact on the surrounding population was minimal. The event was therefore determined to not be reportable. A subsequent review of the event, considering communications made between Cook Nuclear Plant and the Berrien County 911 Dispatch Center, as well as recent industry operating experience of similar events, was performed; its conclusion was to conservatively make a report under 10 CFR 50.72(b)(2)(xi). The licensee has notified the NRC Resident Inspector. | ||
| ENS 48747 | 12 February 2013 20:30:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Notification of Offsite Agencies Due to Discovery of Potential Human Remains | At 1530 EST on February 12, 2013, bones were discovered in the debris removal baskets in the Screen House at the Cook Nuclear Plant. These bones have the potential to be human remains. Local law enforcement agencies have been notified and the remains were removed by law enforcement personnel. The NRC Senior Resident Inspector was notified. Plant operations was not impacted by the event. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) due to notification of offsite agencies and potential for media involvement related to the discovery.
After analysis by the Berrien County Sheriff's Department, it was determined that the bones discovered in the debris removal baskets in the screenhouse at the Cook Nuclear Plant on February 12, 2013 at 1530 EST were not of human origin, but most likely from a deer or other animal. The licensee has notified the NRC Resident Inspector. Notified the R3DO (Pelke). | ||
| ENS 48731 | 7 February 2013 22:35:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Related to Death of Contractor Onsite | At 1620 EST on 2/7/2013 an emergency medical report was received in Unit 1 Control Room that an individual was reported to have collapsed and was lying unconscious outside of the protected area. Fire protection and Emergency Medical personnel were dispatched to the scene. The individual was unresponsive, without a pulse and not breathing. Off-site medical assistance was immediately requested. CPR was commenced and continued until transfer of the individual to off-site medical ambulance service Medic 1. An Automatic External Defibrillator (AED) was used once, as allowed by the AED. Confirmation of the fatality was received at 1735 EST on 2/7/2013. The individual was pronounced dead at 1712 EST on 2/7/2013. Both Units remain at 100% power. This Event notification is being made due to the onsite fatality. The NRC Resident Inspector has been notified. | ||
| ENS 47864 | 26 April 2012 02:46:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Notification to Offsite Agencies Due to Oil Spill | At 2246 EDT on April 25, 2012, D.C. Cook notified the State of Michigan and local authorities of an oil spill from the Unit 2 (Main Generator) Seal Oil system at 2110 EDT which resulted in a portion of this oil entering the absorption pond, which is in the owner controlled area. An oil sheen is present on the absorption pond which has a surface area of approximately 2 acres (87,000 square feet) and it is estimated that five to ten gallons of oil are on the absorption pond. The NRC Resident Inspector was notified. The licensee has contained the oil leak and clean up efforts are ongoing. | ||
| ENS 47194 | 23 August 2011 18:24:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Notification of an Unusual Event Due to a Seismic Event | At 1424 (hrs. EDT) on Tuesday, August 23, 2011, an Unusual Event was declared for Unit 1 and Unit 2 based on Emergency Plan criterion N-1, 'Natural of Destructive Phenomena Inside the Protected Area'. The Unusual Event was declared following detection of ground motion by persons on site with confirmation based on United States Geological Survey information. Plant operation was not impacted by the event. Site structure and system inspections are in progress in accordance with the Abnormal Operating Procedure for earthquake. No damage has been identified. In accordance with Emergency Plan procedures, notifications of Berrien County and State of Michigan were completed. The licensee has notified the NRC Senior Resident Inspector. A follow-up notification will be made after the Unusual Event is terminated. This notification is being made in accordance with 10 CFR 50.72 (a)(1)(i) due to declaration of an emergency class.
A press release has been issued regarding the seismic event. This notification update is being made in accordance with 10 CFR 50.72 (b)(2)(xi) for news release or notification of other government agency. Notifications were made to the following local media: St. Joseph Herald Palladium, South Bend Tribune, Niles Daily Star, WSJM Radio, WNDU TV, WSBT TV, and WSJV TV. Notification was also made to the Platt News Service. The licensee has notified the NRC Resident Inspector.
The Unusual Event due to Seismic Event was terminated at 1723 EDT following an examination of plant systems which revealed no damage due to the seismic event. A press release has been issued regarding the termination of the Unusual Event. This notification update is being made to notify of the Unusual Event termination and also notify of the press release describing the Unusual Event termination in accordance with 10 CFR 50.72 (b)(2)(xi) for news release or notification of other government agency. The licensee has notified the NRC Resident Inspector and state and local authorities. Notified R3DO (Passehl), IRD (Gott), DHS (Flinter), FEMA (Via), USDA (Kraus), and DOE (Bailey). | ||
| ENS 46234 | 8 September 2010 11:47:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release | Offsite Notification Due to Body Discovered in the Owner Controlled Area | At 0747 hours on September 8, 2010, a body was discovered on the beach along the Owner Controlled Area at the Cook Nuclear Plant. Local law enforcement agencies have been notified. It is expected that a press release will be issued from local law enforcement. The NRC Senior Resident Inspector was notified. Plant operation was not impacted by the event. The fatality did not occur on site. This notification is being made in accordance with 10 CFR 50.72(b)(2)(xi) due to notification of offsite agencies and expected media involvement related to the discovery. Although unconfirmed, the licensee believes that the body belongs to a person that went missing on the lake last week. The licensee notified Lake Township, Berrien County Sheriffs Office, Federal Bureau of Investigation and the U.S. Coast Guard. Either Berrien County or Lake Township will be issuing a press release. | ||
| ENS 46037 | 23 June 2010 18:28:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Declaration of Unusual Event Due to Seismic Event | At 1428 (EDT) on Wednesday, June 23, 2010, an Unusual Event was declared for Unit 1 and Unit 2 based on Emergency Plan criterion N-1 'Natural or Destructive Phenomena Inside the Protected Area'. The Unusual Event was declared following detection of ground motion by persons on site, with confirmation based on United States Geological Survey information. Plant operation was not impacted by the event. Site structure and system inspections are in progress in accordance with the Abnormal Operating Procedure for Earthquake. No damage has been identified. In accordance with Emergency Plan procedures, notifications of Berrien County and State of Michigan were completed. The licensee has notified the NRC Senior Resident Inspector. A follow-up notification will be made after the Unusual Event is terminated. This notification is being made in accordance with 10 CPR 50.72 (a)(1)(i) due to declaration of an emergency class.
The licensee provided the following information as an update: A press release has been issued regarding the seismic event. This notification update is being made in accordance with 10 CFR 50.72 (b)(2)(xi) for news release or notification of other government agency. The licensee informed state/local agencies and the NRC Resident Inspector. Notified R3DO (Lara).
The Unusual Event due to Seismic Event was terminated at 1955 EDT following an examination of plant systems which revealed no damage due to the seismic event. A press release has been issued regarding the termination of the Unusual Event. This notification update is being made to notify of the Unusual Event termination and also notify of the press release describing the Unusual Event termination in accordance with 10 CFR 50.72 (b)(2)(xi) for news release or notification of other government agency. The licensee notified state/local agencies and the NRC Resident Inspector. Notified the R3DO (Lara), NRR EO (Cunningham), DHS (Inzer), and FEMA (Hollis). | ||
| ENS 44507 | 21 September 2008 00:18:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration 10 CFR 50.72(b)(3)(iv)(A), System Actuation | Unit 1 Manual Reactor Trip from 100% Power Due to a Fire in the Main Turbine | D.C. Cook Unit 1 declared an Unusual Event (EAL H4 & H5) due to a fire in the Main Turbine. The reactor was manually tripped from 100 percent. The fire occurred at the upper level of the turbine building (Level 633), and was extinguished by the fire suppression system and local fire brigade. Three fire pumps are running at this time. No injuries were reported. All rods fully inserted, auxiliary feed water initiated and decay heat is being removed via atmospheric relief valves. Unit 1 is currently shutdown and stable in Mode 3, Hot Standby. Main steam stop valves are closed. Main condenser vacuum was broke. Unit 2 was not affected. All Unit 1 safety-related equipment is in-service and available. The licensee is currently assessing the extent of damage. The licensee will inform the NRC Resident Inspector. Notified DOE (Morrone), USDA (Shaf) and HHS (Mammarelli) that the NRC entered Monitoring Mode at 2045 EDT.
On September 20, 2008 at 20:05 the DC Cook Unit 1 Reactor was manually tripped after a malfunction occurred on the main turbine generator causing high vibration. A fire in the Unit 1 Main Generator resulted from this malfunction. A Notification of Unusual Event was declared September 20, 2008 at 20:18 due to Event classifications H-4, Fire within the protected area not extinguished within 15 minutes and H-5, Toxic or Flammable gas release affecting plant operation. The Unit 1 Main Generator Fire was reported extinguished at September 20, 2008 at 20:28. The Unit 1 plant trip was uncomplicated and all Automatic Control systems functioned as expected. All control rods inserted on the Reactor trip. The Turbine and both Motor Driven Auxiliary Feedwater pumps automatically started and fed all four Steam Generators as designed. The Steam Generator Stop Valves were manually closed to arrest plant cooldown. The cause of the Main Generator fire has not yet been determined, but the investigation is ongoing. No radiological release resulted from this event. This event is being reported as a four hour report required by 10CFR50.72(b)(2)(iv)(B) due to the Reactor Protection System automatic actuation and as an eight hour report required by 10CFR50.72(b)(3)(iv)(A) for the automatic actuation of the Auxiliary Feedwater system. The Notification of Unusual Event was reported separately. Unit 1 is stable in Mode 3. Shutdown Margin was satisfactorily verified. The main condenser was isolated as the primary heat sink. Steam Generator Power Operated Relief Valves are removing core decay heat in automatic control due to breaking main condenser vacuum. Main condenser vacuum was broken to stop the Unit 1 main turbine generator due to high vibration. Preparations are in progress to cooldown Unit 1 to Mode 5, Cold Shutdown. The Fire Suppression Water System was actuated and one of two 565,000 gallon tanks was drained. The second 565,000 gallon Fire Suppression Water tank was placed in service to restore the Fire Suppression Water system function. The licensee notified the NRC Resident Inspector, local and state authorities. The licensee will likely make a press release. Notified R3RA (Caldwell), R3DO (Stone), NRR (Leeds and Galloway) IRD (McDermott), DHS (Gomez) and FEMA (Kuzia).
At 0409 the licensee terminated from the Notice of Unusual Event. The licensee has established the forced outage recovery team. No fires exist and no conditions conducive to fires exist due to the event. The licensee has established the integrity of the fire protection system. Notified R3RA (Caldwell), R3DO (Stone), NRR (Galloway), IRD (Grant), DHS (Jason), DOE (Maroni), FEMA (Sweetser), USDA (Phillip), and HHS (Nathan). | Steam Generator Reactor Protection System Auxiliary Feedwater Main Turbine Main Condenser Control Rod Main Steam | |
| ENS 44147 | 18 April 2008 10:02:00 | 10 CFR 50.72(b)(2)(xi), Notification to Government Agency or News Release 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Seismic Activity | At 06:02 on April 18 2008, DC Cook Units 1 and 2 entered the Emergency Plan for a confirmed seismic event based on ground motion felt by plant personnel. An immediate notification to the NRC is required under 10 CFR 50.72(a)(3) for entry into the Emergency Plan. The ground motion sensed by plant personnel was confirmed with the National Earthquake Center. A magnitude 5.4 preliminary (Richter scale) earthquake was confirmed in Southern Illinois at LATITUDE 38.481 North/LONGITUDE 87.826 West. The Earthquake Abnormal Operating Procedures were entered for both Units. Ground motion was not felt by the control room operating crews, but was noted and reported by other plant personnel. Plant Process Computer trends of Unit 1 RWST level, South Boric Acid Storage Tank Level and North Chemical and Volume Control System Hold Up Tank Level indicated ground motion. No damage to plant equipment was noted during the initial evaluation of plant status. Investigation of the plant impact of the sensed ground motion is in progress. The NRC Resident Inspectors were notified by phone call. Current Plant status: Unit 1 is shutdown in Mode 6 with Residual Heat Removal Cooling. Unit 2 is operating in Mode 1 at 100% power. AEP system Operations was contacted and the GRID was described as stable and no electrical operations relating to the earthquake event. The Seismic Monitoring system was INOPERABLE as required by TRO 8.3.2, Cond. B, during the event for routine surveillance. This surveillance has been in progress since 03/26/08. No alarms were generated by the seismic monitoring system during this event.
At 0905 EDT on 04/18/08, the licensee terminated the Unusual Event based on completion of system walk downs which confirmed no damage to the facility. The licensee informed the NRC Resident Inspector. Notified R3DO (Kozak), NRR (MJ Ross-Lee), IRD (McDermott), FEMA (Liggett) and DHS (Barnes).
A press release regarding the declaration of the emergency was issued and a subsequent press release is planned to address the termination. The offsite notifications are being reported under 10 CFR 50.72(b)(2)(xi)." The licensee informed the NRC Resident Inspector. Notified R3DO (Kozak).
At 11:45 on April 18, 2008, D.C. Cook Units 1 and 2 entered the Emergency Plan for a confirmed seismic event based on ground motion felt by plant personnel. An immediate notification to the NRC is required under 10 CFR 50.72(a)(3) for entry into the Emergency Plan. The ground motion sensed by plant personnel was confirmed with the National Earthquake Center. A magnitude 4.6 (preliminary on Richter scale) earthquake-aftershock was confined in Southern Illinois at LATITUDE 38.483 North/LONGITUDE 87.39 West at 10:14 CDT / 11:14 EDT. The Earthquake Abnormal Operating Procedures were entered for both Units. Ground motion was not felt by the control room Operating crews, but was noted and reported by other plant personnel. No damage to plant equipment was noted during the initial evaluation of plant status. Investigation of the plant impact of the sensed ground motion is in progress. The NRC Resident Inspectors were notified in person. Current Plant status: Unit 1 is shutdown in Mode 6 with Residual Heat Removal Cooling. Unit 2 is operating in Mode 1 at 100% power. AEP System Operations was contacted and the GRID was described as stable with no electrical operations relating to the earthquake event. The Seismic Monitoring system was INOPERABLE as required by TRO 8.3.2, Condition B during the event for routine Surveillance. This Surveillance has been in progress since 03/26/08. No alarms were generated by the seismic monitoring system during this event. One of four channels is currently out of service. The three remaining seismic monitor channels indicated no ground acceleration above the lowest instrument activation level of 0.02g. D.C. Cook intends to issue a press release regarding the declaration of the Notification of Unusual Event emergency classification. The offsite notifications are being reported under 10 CFR 50.72(b)(2)(xi).
At 16:00 on April 18, 2008, DC Cook terminated the Unusual Event specified in EN 44147 for the aftershock response described above. A press release regarding the emergency event termination is anticipated. The offsite notifications are being reported under 10 CFR 50.72(b)(2)(xi). The licensee notified the NRC Resident Inspector. Notified R3DO (Kozak), NRR EO (Ross-Lee), IRD (McDermott), DHS (Gomez), FEMA (Burckhardt). | Residual Heat Removal | |
| ENS 40402 | 19 December 2003 23:44:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event | At 1844 on 12/19/2003, D.C. Cook Unit 2 received seal injection low flow alarms. Upon investigation, a leak of approximately 30 gpm was identified on the North Seal Injection Filter housing. The abnormal procedure for RCS leakage was entered. An Unusual Event was declared at 1853. A team was dispatched to place the South Seal Injection Filter in service and isolate the North Seal Injection Filter. At 1929, the leak was isolated. The licensee is reviewing UE termination criteria at this time. The Licensee notified the NRC Resident Inspector.
At 2015 EST on 12/19/03 D.C. Cook terminated the Unusual Event. Notified DIRO (Wessman), R3DO (Kozak), NRREO (Black), NSIR (Weber), FEMA, and DHS. |