Semantic search
| Start date | Reporting criterion | Title | Event description | System | LER | |
|---|---|---|---|---|---|---|
| ENS 46739 | 7 April 2011 23:07:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Due to Hydrogen Burn During Maintenance | (The licensee declared an Unusual Event at 1607 PDT due to a) small hydrogen burn when opening the stator cooling water system for maintenance. There were no injuries or equipment damage. The licensee entered EAL 93U3 'Toxic Gases inside the Protected Area Boundary.' The licensee notified state/local agencies and will inform the NRC Resident Inspector. The licensee plans to issue a press release.
(At 2053 PDT,) Columbia has terminated the Unusual Event declared at 1607 (PDT) on 04/07/11. Conditions throughout the plant have remained stable. Columbia has confirmed there is no hazard to personnel safety nor a challenge to safe plant operation. The licensee will notify the NRC Resident Inspector. Notified R4DO (OKeefe), NRR EO (Blount), IRD (Grant), DHS (Jenkins), and FEMA (O'Connell).
At 1922 EDT on April 7, 2011, NRC was notified of an Unusual Event at Columbia Generating Station (EN#46739), The NRC was notified the event was terminated at 2353 EDT on April 7, 2011. Based on further investigation, this event is being retracted. The stator cooling water system contains a mixture of water and hydrogen when in operation. The system had been removed from service, drained and blanketed with nitrogen prior to commencing maintenance. There was no active source of hydrogen in the system. Although the system had been tested for hydrogen and none was detected, the event occurred when workers cut into a section of the system piping where a small amount of residual hydrogen remained. Immediately following the event, tape was placed over the cut to prevent any debris from entering the pipe. Hydrogen measurements were taken in the vicinity of the cut section of pipe and in the general area and concentrations were below hazardous levels. The only elevated reading occurred directly at the cut location when the tape was removed, This indicated that hydrogen, residual in nature, was confined to the inside of the pipe. Since the system was not in use and the residual hydrogen was confined, plant operations were not affected, As a result of this event, no personnel were injured, no equipment was damaged, and there was no impact to structures needed for plant operation. The licensee will notify the NRC Resident Inspector, the media, and local, state, and other government agencies of this update. Notified R4DO(O'Keefe) | Stator Cooling Water | |
| ENS 45245 | 5 August 2009 14:50:00 | 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 | Unusual Event Declared Due to Toxic Gas from a Switchgear Fire in the Turbine Building | At 0750 PDT the licensee experienced a turbine trip and reactor scram. At approximately the same time, a fire was detected in the non-safety related 6.9 kV feed bus to switchgear SH-5 and SH-6 in the turbine building. The fire and associated fault to the switchgear feed bus caused a loss of power to both reactor recirculation pumps and the automatic reactor scram. The fire produced smoke and potentially toxic gases. Due to the presence of potentially toxic gas in the power plant, an Unusual Event was declared at 0812 PDT based on EAL 9.3.U.3. At the present time, the fire is out and the smoke is being cleared from the plant. All rods fully inserted upon the reactor scram. Systems functioned as expected except for problems with the EHC system which resulted in the bypass valves remaining open which caused the reactor to depressurize to approximately 390 psi. MSIVs were manually shut to halt the reactor depressurization and cooldown. Decay heat is being removed via relief valves to the suppression pool with reactor pressure being maintained between 500 and 600 psi. Suppression pool cooling is via RHR. Makeup water to the reactor is via normal feed. Licensee is on natural circulation at the time of this report. Normal shutdown electrical alignment is established with the exception of Division II emergency switchgear which is aligned to the backup transformer. A request for assistance was made to the Hanford fire department, however, the fire was out prior to their arrival on site. The licensee has notified State, local agencies and the NRC Resident Inspector.
The Unusual Event has been terminated as of 1006 PDT. The licensee is taking the unit to cold shutdown. The licensee will notify the NRC Resident Inspector. Notified NRR EO (Ross-Lee), R4DO (Walker), DHS (Enzer), and FEMA (Eaches).
Following the reactor scram, with the turbine bypass valves failed fully open, the inboard main steam isolation valves had to be manually closed to prevent excessive cool down. The outboard main steam isolation valves automatically closed from the inability to maintain condenser vacuum. The inability to maintain condenser vacuum was due to limited equipment access in the Turbine Building from heavy smoke. This is reportable under Part 50.72(b)(3)(iv)(A) as a valid actuation of one of the systems listed in Part 50.72(b)(3)(iv)(B)(2). The licensee notified the NRC Resident Inspector. Notified R4DO (Walker). | Main Steam Isolation Valve Reactor Recirculation Pump | |
| ENS 45169 | 27 June 2009 03:05:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Based on Fire Lasting Greater than 15 Minutes | At 1949 PDT, a small fire was observed between the #1 and #2 bearings on the main turbine involving some lube oil leakage and lagging. The fire brigade was dispatched and at 1953 PDT, the reactor was manually scrammed. At 2005 PDT, the licensee declared an Unusual Event (EAL 9.2.U.1) based on a fire lasting greater than 15 minutes. At 2006 PDT, the fire was reported out. The manual scram was uncomplicated and all systems functioned as required. The reactor is being cooled by normal feedwater and discharging decay heat to the condenser. The licensee is cooling down the reactor to Mode 4. Currently reactor pressure is 495 psi. The licensee has stationed a re-flash watch at the fire location and is assessing any damage that may have occurred. The only damage currently reported involves lagging at the fire location. The NRC Resident Inspector, State and local authorities have been notified.
The licensee terminated the NOUE at 2159 PDT. The termination criteria was the fire is out, a re-flash watch stationed and the plant is stable and transitioning to Mode 4. The licensee has made State and local notifications and has notified the NRC Resident Inspector. Notified R4DO (Powers), IRD (Grant), NRR ET (Lubinski), FEMA (Casto) and DHS (Vestal). | Feedwater Main Turbine | |
| ENS 43290 | 7 April 2007 20:44:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Fire in the Reactor Protection System Division 2 Equipment Room | On April 7, 2007 at 1330 Pacific Daylight Time (PDT) Columbia Generating Station (CGS) experienced an electrical fire in the Reactor Protection System (RPS) Division 2 equipment room. Currently, reactor level is stable and being controlled with the feedwater system. Reactor pressure is stable and being controlled with the turbine bypass valves in automatic. All safety systems are functional and there were no ECCS system actuations. At this time the plant is stable and the source of the fire was an electrical transformer which feeds the alternate electrical power supply to a Division 2 inverter isolation logic. Plant operation was not impacted and the plant continues to operate at about 95% power. The first responder on-site extinguished the fire with a hand held fire extinguisher at about 1339 local time. The licensee has informed the NRC Resident Inspector. * * * UPDATE AT 1758 EDT ON 4/7/07 FROM F. SCHILL TO P. SNYDER * * * The Emergency Action Level (EAL) entry condition for the Alert was a 'report by plant personnel of visible damage to equipment contained in a safe shutdown building' EAL 9.2.A.1. The equipment damaged was the backup power supply to the inverter. CGS has a fire watch established in the area to watch for reflash. * * * UPDATE AT 2024 EDT ON 4/7/07 FROM F. SCHILL TO P. SNYDER * * * The Alert condition was terminated at 1721 PDT based on the fact that no reflash was seen by the fire watch, the extent of the equipment damage is understood and the area is now cool. Notified: R4DO (Cain), NRR EO (Haney), IRD Mgr. (Blount), R4 (Gwynn), DHS (Akers), FEMA (Sweetser), USDA (Jimenez), HHS (Dalziel), EPA (Natl. Resp. Cntr. - Crews). | Feedwater Reactor Protection System | |
| ENS 42450 | 28 March 2006 21:57:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Due to Range Brush Fire Near Plant | The licensee declared an unusual event due to a range brush fire primarily involving tumbleweeds that is several hundred yards outside of the protected area. The basis for the declaration is EAL 9.4.U.3 for a fire near the plant that threatens to reduce the level of safety. The fire currently is not threatening anything (such as offsite power lines or buildings). The plant is not in any major limiting conditions of operation (LCO). The Hanford Fire Department has responded. The criteria for termination of the UE is when the fire is extinguished. The licensee has notified State and local authorities and the NRC Resident Inspector.
At 1640 PST on March 28, 2006, Columbia Generating Station exited Unusual Event status due to the Emergency Action Level condition no longer being valid. The range fire reported earlier no longer has the potential to reduce the level of safety. The range fire is under control after burning approximately 0.4 acres approximately 150 yards southeast of the protected area boundary. Two engines from the Hanford Fire Dept. responded. No offsite power sources were affected or threatened. No press release is planned. The licensee notified the NRC Resident Inspector. R4DO(Powers), NRR EO(Gillespie), IRD(Wilson), DHS(Hill), and FEMA(Liggett) notified.
Event Notification 42450 has the statement 'The plant is not in any major limiting conditions of operation (LCO).' This statement should read 'The plant is not in any major Technical Specification Action Statements due to this event.' Unrelated to the declaration of the Unusual Event, the plant had a 125 V dc battery pilot cell that was inoperable per the requirements of TS 3.8.6. Applicable TS Action Statements were entered. At the time of the NOUE, plant personnel were in the process of restoring the battery to operability. The operability of the battery was restored at 1547 on 03/28/06. The licensee will notify the NRC Resident Inspector. R4DO (Powers) notified. | ||
| ENS 41792 | 24 June 2005 06:21:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Licensee Declared an Unusual Event Due to Detection of a Flammable Gas in the General Services Building | An NOUE was declared at the site at 2327 PDT due to the discovery of flammable gas in the General Services Building (office space) which is attached to the turbine and reactor building. The source and type of gas has not been identified and investigation is ongoing by HAZMAT trained personnel. The highest level of flammability measured is 50% of LEL (Lower Explosive Limit). The building has been evacuated. The NRC Resident Inspector will be notified and State local and other Gov agencies have been notified.
EAL # 9.3.U.3 - Report or detection of toxic or flammable gases that could enter or have entered within the Protected Area Boundary in amounts that could affect the health of plant personnel or safe plant operation. The event has been terminated based on a thorough survey of the building by HAZMAT personnel. The building in question has been determined to be free of any flammable gases. Probable source of gas is from a sewage treatment plant. The gas was carried by a stable breeze to the building's air intake. Immediately prior to the event, initial reports of odorous gas from several building occupants was confirmed using portable instrumentation. The highest flammable gas levels were found at a building air intake. Dissipation of gas concentration was accomplished using normal building ventilation. The NRC Resident Inspector will be notified and State local and other Gov agencies have been notified. Notified R4 DO (R. Bywater), NRR EO (M. Case), IRD Manager (S. Frant), DHS (Ceasar), and FEMA (Sullivan). | ||
| ENS 41565 | 6 April 2005 00:12:00 | 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Unusual Event Declared Under E.A.L. 9-3.U.1 | The following information was obtained from the licensee via facsimile (licensee text in quotes): Columbia Generating Station has declared an unusual event ((EAL) 9-3.U.1) due to an unintentional vehicle crash into the Radwaste Building (Safe-Shutdown Bldg) roll-up door during the normal course of plant activities. Damage to the door has prevented normal closure of the door. Efforts to close the door are on-going. Terminated the event @ 1655 (PDT) due to determination that an unusual event did not exist. A plant employee was using a plant-owned vehicle to move a sea-land container into the Radwaste Building when he struck the bottom of the roll-up door. There were no injuries to plant personnel and no other damage to plant equipment. The licensee has notified the NRC Resident Inspector.
The following retraction was obtained from the licensee via facsimile (licensee text in quotes): At 1912 EDT on April 5, 2005, NRC was notified of an Unusual Event at Columbia Generating Station (EN #41565). This notification also informed the NRC that the event was terminated at 1955 EDT (1655 PDT) on April 5, 2005. This is a follow-up to inform the NRC that Columbia Generating Station is retracting its Unusual Event Declaration due to the following reason. Columbia Generating Station Procedure 13.1.1A requires entry into Unusual Event EAL 9.3.U.1 if 'the impact is of such force that damage to structures or equipment inside a Safe Shutdown Building may have occurred.' Upon further evaluation, the impact was not of sufficient force to have caused damage to structures or equipment inside a Safe Shutdown Building. Based on this information, the Unusual Event criteria was not met. The licensee notified the NRC Resident Inspector and local, State, and other Government Agencies of this update. Notified IRD (Kennedy), R4DO (Howell), NRR EO (Lyons), FEMA (Liggett) and DHS (Frost) and HQPAO (Brenner). | ||
| ENS 40910 | 30 July 2004 17:00:00 | 10 CFR 50.72(b)(2)(iv)(B), RPS System Actuation 10 CFR 50.72(a)(1)(i), Emergency Class Declaration | Alert Declared at Columbia Generating Station | The following information was obtained by the licensee via facsimile: Reactor SCRAM received at 0924 (hrs) PDT. Initial indications are the scram signal was caused by RPS (Reactor Protection System) High Pressure. Following the scram, 2 (two) control rods did not immediately indicate (fully inserted). Control room staff entered (procedure) PPM5.1.2 and took the required actions. All control rods subsequently indicated (fully inserted). An ALERT Classification was declared at 1000 (hrs) based on PPM 13.1.1 Criteria 2.2.A.1, 'RPS Setpoint exceeded and automatic actions failed to result in a rod pattern which alone assures reactor shutdown'. Manual actions resulted in all rods (fully inserted) and reactor power (less than or equal to) 5 percent. All other plant systems responded as expected with the exception of a wetwell-to-drywell vacuum breaker which indicates open. Investigation into the cause of the scram and actual control rod position is ongoing. Further details will be provided when available. The licensee also reports that no relief valves lifted during the transient. Decay heat removal is via the main condenser. Reactor level is steady at 36 inches. Reactor temperature and pressure are 507 degrees and 710 psig respectively. Offsite power is available. All emergency systems are available in standby. The licensee has notified the NRC Resident Inspector of the incidents. The NRC entered Monitoring mode at 1327 hrs EDT with Region IV leading. The NRC exited Monitoring at 1530 hrs. EDT and returned to Normal mode. Notified HHS (Ayles) as well as others noted in notification block.
At 1358 (hrs.) EDT on 7/30/04, NRC was notified of an Alert at Columbia Generating Station (EN #40910). This is a follow-up to inform NRC that the event was terminated at 1457 (hrs) (EDT) (1157 PDT). All control rods are inserted. Reactor is shutdown and water level is normal. All required emergency systems are operable. All offsite and onsite power sources are operable. Reactor pressure is normal. The licensee has notified the NRC Resident Inspector, State of Washington and local authorities of the termination. The NRC Operations Center notified R4DO(Bywater), DHS, FEMA, DOE(NRC), USDA, EPA and CDC(HHS).
At 1358 EDT on July 30, 2004, NRC was notified of an Alert at Columbia Generating Station (EN #40910). A subsequent notification was made to inform the NRC that the event was terminated at 1157 PDT (1457 EDT) on July 30, 2004. This is a follow-up to inform the NRC that Columbia Generating Station is retracting its Alert Emergency Declaration due to the following reason. Following the RPS actuation, control rod position indication for two control rods was indeterminate for approximately two minutes to the control room staff. A subsequent review of control rod position indication from the Plant Data Information System (PDIS), Rod Worth Minimizer (RWM) logs, and Auto Scram Timer (AST) data by Columbia Generating Station personnel shows that all rods were successfully inserted to the 'Full-in' position following the initial RPS actuation, assuring that the reactor was shutdown under all conditions. The Emergency Action Level for this Alert classification requires that the following three conditions be met: Any RPS set point (including manual) has been exceeded per T.S. 3.3.1.1 AND RPS actuation failed to result in a control rod pattern which alone always assures reactor shutdown under all conditions AND Manual actions (mode switch in shutdown, manual push buttons, and ARI) result in reactor power LE 5%. Since all rods were successfully inserted without the assistance of any manual actions and within the Technical Specification required time, Columbia Generating Station staff now believes that no emergency classification should have been made, and we are retracting the Alert emergency classification from this event notification. The problem with control rod position indication following the scram is being addressed through our corrective action program. The licensee notified the NRC Resident Inspector and will notify local, State, and other Government Agencies of this update. Notified R4 DO (Runyan). | Decay Heat Removal Rod Worth Minimizer Main Condenser Control Rod |