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| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 49219 | 27 July 2013 04:49:00 | 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 | Unusual Event Declared Due to a Fire in the Turbine Building Lasting Greater than 15 Minutes | On July 26, 2013, at 2349 CDT, the Callaway nuclear power plant declared an Unusual Event due to a fire not extinguished within 15 minutes of control room notification, EAL HU 2.1. The fire was located in the turbine building near the main generator. Concurrent with the fire, the reactor tripped due to a turbine trip. All control rods fully inserted and all reactor coolant pumps (RCPs) tripped. The fire has been extinguished and the licensee is in progress of restoring RCPs. The licensee notified the NRC Resident Inspector, State Emergency Management Agency and Local Authorities. Notified DHS SWO, FEMA, and DHS NICC.
The licensee terminated the Unusual Event at 0101 CDT. Decay heat is being removed via aux feed water from the steam generators to the condenser. Visual inspection determined the location of the fire to be in the phase B generator bus duct. Notified R4DO (Allen), NRR EO (Monninger), IRD (Marshall), DHS SWO, FEMA, and DHS NICC.
The licensee made notifications under 10CFR50.72(b)(2)(iv)(B) (RPS Actuation), 10CFR50.72(b)(2)(xi) (Offsite Notification) and 10CFR50.72(b)(3)(iv)(A) (ESF Actuation - AFW). The licensee will be making a press release and notifying the NRC Resident Inspector. Notified R4DO (Allen).
Upon further review, the licensee believes that the initially reported EAL for the UE notification, HU 2.1, was not applicable. Although indications of a fire were present for greater than 15 minutes, the criteria at Callaway apply to a fire within 50 feet of safety related equipment. There was no safety related equipment within 50 feet of where the fire occurred. The proper EAL classification should have been HU 3.1 due to release of potentially toxic gas or asphyxiant or flammable gas that could impact plant operation. This EAL is applicable due to the heavy smoke release from burning electrical insulation and melted bus and ductwork which prevented access to the turbine building area where the fire took place. The licensee will notify the NRC Resident Inspector of this update. Notified R4DO (Allen). | Steam Generator Control Rod | 05000483/LER-2013-008 |
| ENS 47275 | 18 September 2011 15:56:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Alert Declared Due to a Freon Gas Release Into a Safe Shutdown Equipment Area | An Alert was declared at Callaway Nuclear Plant at 1056 (CDT) due to EAL HA3.1. Access to an Auxiliary Building area which is prohibited due to release of toxic gas which jeopardizes operation of systems required to maintain safe operations or safely shutdown the reactor. EAL HU3.1 (Unusual Event) is also applicable at the same time. The cause of the toxic gas release was a Freon gas leak from the 'A' Control Room air conditioner unit. The licensee has notified the NRC Resident Inspector and state and local government. Also notified USDA (Pitt) and HHS (Emerson).
At 1737 CDT, Callaway Nuclear Plant exited from the Alert for EAL HA3.1, and exited from the Unusual Event for EAL HU3.1. The plant continues to operate at 100% power in Mode 1. There was no radiological release due to this event. Additionally, a press release will be performed after the event closeout. The licensee has notified the NRC Resident Inspector and state and local government. Notifications were also given to R4DO (Pick), NRR EO (Giitter), IRD-MOC (Morris), HQ PAO (Hayden), DHS (Gates), FEMA (Via), DOE (Foote), USDA (Sanders) and HHS (Hoskins). | ||
| ENS 45837 | 13 April 2010 17:00:00 | 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 an Identified Leakage Exceeding 25 Gallons Per Minute | On April 13, 2010 at 1200 CDT, Callaway Unit 1 declared an Unusual Event due to identified leakage of greater than 25 gallons per minute (EAL SU6.1). During the flushing of the 'A' Chemical and Volume Control System mixed bed demineralizer, a leak occurred from the vent valve exceeding 25 gallons per minute for approximately 5 minutes. The leak was isolated and the Unusual Event was terminated at 1223 CDT. No personnel contamination or outside release occurred. The licensee has notified the State and local authorities and the NRC Resident Inspector.
Callaway Plant declared an Unusual Event at 1200 CDT on 4/13/2010. The cause of the event was Emergency Action Level (EAL) SU6.1, identified leakage greater than 25 gallons per minute (gpm). When attempting to place the 'A' Chemical and Volume Control System (CVCS) mixed bed demineralizers in service, a drop in the Volume Control Tank (VCT) level was noted by the Reactor Operator (RO). Technical Specification (TS) 3.4.13 Condition A was entered at 1033 CDT upon identification of identified leakage of the Reactor Coolant System (RCS) greater than 10 gpm. TS 3.4.13 Condition A requires reduction of leakage to limits within 4 hours. The leakage was verified to be stopped at 1038 CDT, at which time TS 3.4.13.A was exited. The system was restored to a normal alignment. Upon review, it was determined that the VCT level dropped approximately 125 gallons in 5 minutes. EAL SU6.1 was declared at 1200 CDT and closed at 1223 CDT. The state and local counties (Callaway, Gasconade, Montgomery, and Osage) were notified of the event at 1210 CDT and of the event closeout at 1227 CDT. The NRC Resident Inspector was notified of the event. A news release will be made by Ameren Corporate Communications. Notified R4DO (Spitzberg), NRR EO (Nelson), and IRD (Marshall).
The declaration of Unusual Event SU6.1, RCS leakage, on 4/13/10 is being retracted, because the declaration was inaccurate. The leak was an isolable intersystem leak of the CVCS, not RCS leakage, and the leak was stopped within the 15 minute time period allowed to determine EAL applicability. Therefore, the leakage did not meet the Initiating Condition for the EAL. The NRC Resident Inspectors have been notified. Notified R4DO (J. Whitten). | Reactor Coolant System | |
| ENS 44864 | 19 February 2009 16:21:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Main Generator Hydrogen Gas Leak | An Unusual Event was declared at 1021 CST due to toxic, corrosive, flammable gasses in amounts that have or could adversely affect normal plant operations. Licensee estimated that a plume of hydrogen gas 20 feet high was leaking in the Turbine Building at the North Generator Bearing. Licensee entered EAL HU3.1. There was no release above normal operating limits (0.1 Mr/hr at EAB). No offsite response required. Gas is being dissipated via emergency degassing of Main Generator. Presently, the Main Generator degas has been completed and no flammable environments remain. The Unusual Event will stay in effect until the area is accessible to personnel, as evaluated by chemistry. There was no fire or personnel injury related to this event. The Plant was already in Mode 3 due to an earlier event requiring a Technical Specification Action 3.3.2.Q shutdown. The licensee has notified the NRC Resident Inspector, and local, state and other government agencies. No media press release was anticipated.
The hazard was eliminated by 1055 on 2/19/2008. The Unusual Event was closed out at 1115. The state and counties (Callaway, Gasconade, Montgomery, and Osage) were notified of the event closeout at 1126. A news release will be made by Ameren Corporate Communications. The licensee has notified the NRC Resident Inspector. Notified R4DO (Powers), DHS ( Cassandra McKentry) and FEMA (Mike Eaches). | ||
| ENS 43622 | 7 September 2007 04:22:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Leakage from Reactor Coolant System >10 Gpm | A relief valve (BG 8117) in the letdown system opened and released about 650 - 700 gallons of water from the reactor coolant system into the pressurizer relief tank. The rate of release from the letdown was 119 gpm. It was estimated that the pressurizer level lowered about 2-3%. The letdown system was isolated by closing the letdown orifice block isolation valve. Licensee is investigating the reason for the spurious lifting of the relief valve. Due to leakage from the reactor coolant system, the licensee entered EAL 4R. Plant is stable and operating at full power. The licensee notified the NRC Resident Inspector.
The licensee stated that the Unusual Event was exited at 0120 EDT. The licensee notified the NRC Resident Inspector. Notified R4DO (Pruett) and NRR EO (Evans) and IRD MOC (Cruz).
The licensee is retracting this report based on the following: This is a follow-up notification to inform the NRC that Callaway Plant is retracting an Unusual Event declaration reported on 09/07/2007 at 00:52 EDT. EAL 4R was entered and the declaration was made due to leakage from the reactor coolant system. The basis for EAL 4R indicates that the initiating condition for an Unusual Event would include failure of a relief valve to properly close following reduction of applicable pressure and NOT simply the actuation of the relief valve as designed. Based on troubleshooting efforts and upon review of the event, it has been determined that relief valve BG8117 functioned as designed to reduce pressure and therefore the declaration of the Unusual Event was not required. The relief valve did sense an over-pressurization and did perform its intended function. The relief valve reseated when the letdown line was isolated. Based on this, the Unusual Event declaration is retracted. The licensee informed the NRC Resident Inspector. Notified R4DO (Cain), EO (MJ Ross) and IRD (Blount). | Reactor Coolant System | |
| ENS 43279 | 5 April 2007 15:23:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Alert Declared Due to a Fire in the Control Bulding | At 1023 Central Daylight Time the licensee declared an Alert due to a transformer fire in the non-safety related PN08 transformer phase 'A.' There were no visible flames seen by onsite licensee personnel but an area of the transformer was glowing with a smokey haze in the area. The fire brigade responded. The plant was already in a shut down condition entered on 4/1/07 for a refueling outage. Decay heat was being removed using Residual Heat Removal the train 'B.' The licensee declared the alert based on a potential impact to the operating Residual Heat Removal train. The licensee notified the NRC Resident Inspector. * * * UPDATE AT 1215 ON 4/5/07 FROM LICENSEE COMMUNICATOR TO SNYDER * * * The licensee exited the Alert condition at 1215 Eastern Daylight Time based on their assessment that no impact to operating safety related RHR equipment occurred and any impact would have been conservative in that flow to the core would not have been interrupted. The licensee notified the NRC Resident Inspector. | Residual Heat Removal |