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 Start dateSiteRegionReactor typeEvent description
ENS 5732918 September 2024 15:15:00ColumbiaNRC Region 4GE-5

The following information was provided by the licensee via email: On September 18, 2024, Columbia Generating Station determined that lubricating oil was likely released into the plant service water system due to a failed heat exchanger on the reactor feed turbine alpha. Isolation of the heat exchanger from the plant service water system is in progress. The plant service water system returns water to a water basin that contains, at a minimum, 300,000 gallons of water. The water basin is connected to the Columbia River via a blowdown line. The blowdown line was secured at 0739 PDT on 9/18/2024. A visual inspection of the basin did not identify any oil sheen or film, but a sample downstream of the affected heat exchanger revealed an oily sheen in the sample bottle. It does not appear the oil released poses a threat to human health or the environment. However, there could have been a discharge of an unknown quantity of oil into the Columbia River. This matter is immediately reportable under Revised Code of Washington 90.56.280 to the U.S. Coast Guard National Response Center, Washington State Department of Ecology, and to the Energy Facility Site Evaluation Council per National Pollutant Discharge Elimination System (NPDES) permit section S3.F.2.b.i. This condition is being reported pursuant to 10 CFR 50.72(b)(2)(xi) for notification of other government agencies concerning an event related to the health and safety of the public or protection of the environment. Notifications to off-site agencies were performed at 0850 PDT on 9/18/2024. The NRC Resident Inspector has been notified. United States Coast Guard National Response Center Incident Report #141183 Washington State Department of Ecology #733853

  • * * RETRACTION ON 10/10/24 AT 1513 EDT FROM CHASE WILLIAMS TO KAREN COTTON * * *

The following information was provided by the licensee via email: On September 18, 2024, Columbia Generating Station notified the NRC (event notification 57329) under 10 CFR 50.72(b)(2)(xi) of an offsite notification for potential oil release to the plant service water system and potentially the Columbia River. Further troubleshooting efforts refuted the possibility of leakage from the heat exchanger to the plant service water system. Engineering determined the most likely path of oil leakage was through a seal in the reactor feed turbine 'A' pump. This leakage would exit with seal water leak-off into the marine oil separator into collection barrels which are collected and processed. Since troubleshooting efforts determined oil leakage was not from the heat exchanger to the plant service water system, the offsite notification retractions were completed as of October 10, 2024, and therefore event notification 57329 is being retracted. The NRC Resident Inspector was notified. Notified R4DO (Gaddy).

ENS 5731410 September 2024 23:30:00ColumbiaNRC Region 4GE-5The following information was provided by the licensee via email: On September 10, 2024, Columbia Generating Station determined that no more than approximately thirty (30) gallons of silicone oil was inadvertently released into a plant service water system due to a failed heat exchanger on a plant installed air compressor. The plant service water system returns water to a water basin that contains at a minimum 300,000 gallons of water. The water basin is connected to the Columbia River via a blowdown line. The compromised heat exchanger and compressor have been isolated and secured from the plant service water system. Although not confirmed, it is suspected that an unknown quantity of silicone oil may have been released to the Columbia River. A visual inspection of the basin did not identify any oil sheen or film, and there are no additional actions needed to mitigate this issue. It does not appear the oil released poses a threat to human health or the environment, however, because there could have been a discharge of an unknown quantity of silicone oil into the Columbia River, this matter is immediately reportable under (Revised Code of Washington) 90.56.280 to the U.S. Coast Guard National Response Center, Washington State Department of Ecology, and to the State of Washington Energy Facility Site Evaluation Council (EFSEC) under the site's National Pollutant Discharge Elimination System (NPDES) permit section S3.F.2.b. This condition is being reported pursuant to 10 CFR 50.72(b)(2)(xi) for notification of other government agencies concerning an event related to the health and safety of the public or protection of the environment. Notifications to off-site agencies are in progress. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The NRC resident inspector will be notified.
ENS 571635 June 2024 04:41:00ColumbiaNRC Region 4GE-5

The following information was provided by the licensee via fax or email: On June 4, 2024, at 2141 PDT, with the unit in Mode 1 at 100 percent power, the reactor protection system (RPS) 'B' power supply unexpectedly de-energized which caused containment isolations to occur in reactor water clean up, equipment drains radioactive, floor drains radioactive, reactor recirculation, and traversing in-core probe systems. All actuations occurred as designed upon the partial loss of RPS power. This event is being reported pursuant to 10 CFR 50.72(b)(3)(xiii) as a major loss of emergency assessment capability due to the inability to assess primary containment identified and unidentified leakage rates. Emergency assessment capability was restored at 2204. The NRC Senior Resident has been notified.

  • * * UPDATE ON 8/1/24 AT 1925 EDT FROM CHASE WILLIAMS TO ADAM KOZIOL * * *

A clarification for reactor recirculation valve isolation above - the flow path was administratively isolated prior to the event. After further evaluation it has been confirmed that the containment isolations were not caused due to any actual plant conditions or system parameters that satisfied the requirements for isolation. The isolations were a result of loss of power to the RPS 'B' bus and therefore are not considered valid actuations. As indicated in 10 CFR 50.73(a)(1), in the case of an invalid actuation reported under 10 CFR 50.73(a)(2)(iv)(A), the licensee may, at its option, provide a telephonic notification to the NRC Operations Center within 60 days of discovery of the event instead of submitting a written licensee event report. This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) for invalid actuations reported under 10 CFR 50.73(a)(2)(iv)(A). Notified R4DO (Werner)

ENS 570137 March 2024 00:35:00ColumbiaNRC Region 4GE-5The following information was provided by the licensee via email: On March 6, 2024, at 1635 PST, with Columbia Generating Station operating at 100 percent power in Mode 1, there was a malfunction in the halogenation/dehalogenation system. This system is used for continuous control of the biological growth in the circulating water and plant service water systems as well as to prevent discharge of halogens to the Columbia River during continuous blowdown. The result of this malfunction was exceeding the established limits of 0.1 milligrams/liter (mg/L) for total residual halogen (TRH) in the station's national pollutant discharge elimination system (NPDES) permit. At the time of discovery, the local indication for TRH was 3.20 mg/L. This was confirmed via a local grab sample. This maximum daily effluent limit is the highest allowable daily discharge, measured during a calendar day. The station NPDES permit requires notification to the Energy Facility Site Evaluation Council (EFSEC). The automatic isolation function of the system failed to isolate the continuous blowdown line as did the emergency trip push button. The system was manually secured, and the continuous blowdown line to the Columbia River was isolated. The cause of the issue is under investigation. Notification was made to EFSEC on March 6, 2024, at 2303 PST. This event is being reported as a four hour report made in accordance with 10 CFR 50.72(b)(2)(xi) due to a "News Release or Notification of Other Government Agency" related to protection of the environment. The NRC Senior Resident Inspector has been notified.
ENS 5692818 January 2024 20:04:00ColumbiaNRC Region 4GE-5

The following information was provided by the licensee via email: On January 18, 2024, at 0030 PST, diesel generator 2 (DG2) was shut down following a monthly surveillance run. Subsequently, a leak was discovered in the DG2 building. Service water pump '1B' was secured at 0117, effectively stopping the leak. The leak was determined to be service water coming from a diesel generator mixed air cooling coil. Service water system 'B' and DG2 were subsequently declared inoperable at 0135. After discussion with engineering, it was identified that the amount of service water leakage from the cooling coil was assumed to be greater than the leakage allowed by the calculation to assure adequate water in the ultimate heat sink to meet the required mission time of 30 days. At 1204, it was determined that entry into Technical Specification 3.7.1 condition D was warranted since the assumed leakage from the cooling coil could exceed the calculated allowed value. At 1238, the control power fuses for service water pump '1B' were removed. DG2 and service water system 'B' were declared unavailable, and the technical specification condition for the inoperable ultimate heat sink was exited. With the control power fuses removed, the pump is kept from auto starting, effectively preventing the leak and ensuring the safety function of the ultimate heat sink is maintained while the cooling coil is repaired or replaced. Due to the leakage assumed greater than the calculated allowable value this condition is reportable per 10 CFR 50.72(b)(3)(ii)(B) as an unanalyzed condition and per 10 CFR 50.72(b)(3)(v)(B) as an event or condition that could have prevented fulfillment of the safety function of structures or systems that are needed to remove residual heat. There was no impact to the health and safety of the public. The NRC Resident has been notified.

  • * * RETRACTION ON 3/18/24 AT 1923 FROM VALERIE LAGEN TO KAREN COTTON * * *

The following information was provided by the licensee via email: On January 18, 2024 at 2138 EST, Columbia Generating Station notified the NRC under 10 CFR 50.72(b)(3)(ii)(B) of an unanalyzed condition on the available capacity of the ultimate heat sink (UHS) and under 10 CFR 50.72(b)(3)(v)(B) of an event or condition that could have prevented fulfillment of the safety function of structures or systems needed to remove residual heat. On January 18, 2024, following monthly surveillance of the diesel generator DG2, a DG2 room cooler flow alarm was received at 0115. A leak was discovered in the diesel mixed air (DMA) air handler unit. Service Water Pump '1B' was secured and the leakage was stopped at 0117. The service water system 'B' and diesel generator system 'B' were declared inoperable at 0135. The leak was assumed to be greater than that allowed to ensure adequate water in the UHS required to meet the 30-day mission time, and the UHS was declared inoperable at 1204. Control power fuses for the service water pump '1B' were removed to fully eliminate the leakage path from the cooler, and the UHS was declared operable at 1238. Following the event, engineering performed an analysis based on the size and location of the leak, and concluded it would have taken 1.4 days to deplete the available excess water in the UHS to below the minimum technical specification required water level of the spray pond. Operations were able to secure the service water subsystem of the UHS prior to exceeding the volumetric margins in the spray ponds to ensure the 30-day mission time was met. The condition did not represent a safety significant unanalyzed condition nor a loss of safety function. The NRC Resident Inspector has been notified. Notified R4DO (Gepford).

ENS 5662817 July 2023 18:11:00ColumbiaNRC Region 4GE-5The following information was provided by the licensee via email: This report is being made pursuant to 10 CFR 26.719(b)(1). At 1111 (PDT) on 7/17/23, a knowledgeable individual received test results from a lab which identified a prohibited substance that was found in the protected area during the recent refueling outage. This prohibited item was found on 5/21/23 in an infrequently accessed area, the condenser bay, and removed from the protected area. The item was old and is surmised to be from construction. Residual ash on the prohibited item tested positive for a prohibited substance. The licensee notified the NRC Resident Inspector.
ENS 5657214 June 2023 01:42:00ColumbiaNRC Region 4GE-5The following information was provided by the licensee via email: On 6/13/23 at approximately 1030 PDT, testing was being conducted on a lubricating oil system which interfaces with a cooling water system that has a pathway to the Columbia River. Due to an equipment failure, an indeterminate amount of oil leaked into the cooling water system, with a maximum potential loss of 300 gallons of oil. At 1230 PDT, an oil sheen was identified on the water basin which is the suction and discharge for this cooling system. The discharge pathway to the river was isolated at 1235 PDT. Investigation at the Columbia River showed no signs of oil sheen. This is being reported to offsite agencies under the Columbia Generating Station NPDES (National Pollutant Discharge Elimination System) Permit section S3.E.b. l and RCW (Revised Code of Washington) 90.56.280 due to the discharge of oil which has the potential to cause a sheen on the surface of the river. This condition is being reported pursuant to 10CFR50.72(b)(2)(xi) for news release or notification of other government agencies related to health and safety of the public or protection of the environment. Notifications to off-site agencies were performed at 1842 PDT on 6/13/2023. United States Coast Guard National Response Center Incident Report# 1369989. Washington State Emergency Management Division Report# 23-2245. Discharge pathway will remain secured until on-site cooling water system has been remediated. The NRC resident has been informed.
ENS 5662517 May 2023 10:39:00ColumbiaNRC Region 4GE-5The following information was provided by the licensee email: At 0339 CDT on May 17, 2023, diesel generator 3 (DG3) had an auto-start during a surveillance test of excess flow check valves in containment atmosphere instrument sensing lines. During the surveillance, workers failed to recognize residual pressure in the system from the test. Per procedure, MS-PS-47C (main steam pressure switch) was placed back in service, resulting in initiation logic for both the high pressure core spray (HPCS) system and DG3 auto-start. Because the HPCS system was tagged out of service for maintenance it did not actuate. The auto-start of DG3 was an expected response to the high drywell pressure indication. The signals cleared, and DG3 was shutdown per procedure. As indicated in 10 CFR 50.73(a)(1), in the case of an invalid actuation reported under 10 CFR 50.73(a)(2)(iv)(A), the licensee may, at its option, provide a telephonic notification to the NRC Operations Center within 60 days of discovery of the event instead of submitting a written licensee event report. This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) for invalid actuations reported under 10 CFR 50.73 (a)(2)(iv)(A). This actuation was invalid since it was caused by programmatic issues in quality of procedural guidance and not the result of actual plant conditions warranting auto-start of DG3. The actuations were not initiated in response to actual plant conditions, this was not an intentional manual initiation, and there were no parameters satisfying the requirements for initiation. Therefore, this event has been determined to be an invalid actuation. Diesel generator 3 system responded as designed to the actuation signal. The HPCS system did not actuate since it was tagged out of service. There was no impact on the health and safety of the public or plant personnel. The following information is provided as specified in NUREG-1022: (a) The diesel generator 3 was actuated. (b) The actuation of DG3 was complete. (c) The DG3 train was started and functioned successfully. The NRC Resident Inspector has been notified.
ENS 5596828 June 2022 18:16:00ColumbiaNRC Region 4GE-5A non-licensed supervisor had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's unescorted access has been terminated. The NRC Resident Inspector has been notified.
ENS 5593813 June 2022 16:23:00ColumbiaNRC Region 4GE-5

The following information was provided by the licensee via email: During thermography of a reactor protection system (RPS) distribution panel, a circuit breaker (RPS-CB-7B) was inadvertently opened. This resulted in a partial loss of power to RPS Division B, which caused containment isolations to occur in multiple systems (Reactor Water Clean Up, Equipment Drains Radioactive, Floor Drains Radioactive, Reactor Recirculation, and Traversing lncore Probe). Specifically, RWCU-V-1, FDR-V-3, EDR-V-19, RRC-V-19, and TIP-V-15 all closed. All actuations occurred as designed upon the partial loss of RPS power. This event is being reported pursuant to 10 CFR 50.72(b)(3)(iv)(A) due to an unplanned valid actuation of a system pursuant to 10 CFR 50.72(b)(3)(iv)(B)(2). Additionally, this is being reported pursuant to 10 CFR 50.72 (b)(3)(xiii) for a major loss of emergency assessment capability due to the inability to assess primary containment identified and unidentified leakage rates. Emergency assessment capability was restored at 1008 PDT upon system restoration. The NRC resident was notified by the licensee.

  • * * UPDATE FROM SIMEON MORALES TO DONALD NORWOOD AT 1547 EDT ON 6/16/2022 * * *

The following information was received via email: This event is being reported pursuant to 10 CFR 50.72 (b)(3)(xiii) only for a major loss of emergency assessment capability due to the inability to assess primary containment identified and unidentified leakage rates. The containment isolation was not due to actual plant conditions or parameters meeting design criteria for containment isolation. Therefore, this is considered an invalid actuation. Updated ENS Text: During thermography of a reactor protection system (RPS) distribution panel, a circuit breaker (RPS-CB-7B) was inadvertently opened. This resulted in a partial loss of power to RPS Division B, which caused containment isolations to occur in multiple systems (Reactor Water Clean Up, Equipment Drains Radioactive, Floor Drains Radioactive, Reactor Recirculation, and Traversing Incore Probe). Specifically, RWCU-V-1, FDR-V-3, EDR-V-19, RRC-V-19, and TIP-V-15 all closed. All actuations occurred as designed upon the partial loss of RPS power. This is being reported pursuant to 10 CFR 50.72 (b)(3)(xiii) for a major loss of emergency assessment capability due to the inability to assess primary containment identified and unidentified leakage rates. Emergency assessment capability was restored at 1008 PDT upon system restoration. The plant is stable, and all effected systems have been restored. There was no impact to the health and safety of the public or plant personnel. The NRC resident has been notified. Notified R4DO (Azua).

  • * * UPDATE FROM TRACY HOWARD TO ERNEST WEST AT 1853 EDT ON 8/10/2022 * * *

The following information was received via email: At 0923 (PDT) on June 13, 2022, a partial loss of power to the Reactor Protection System (RPS) 'B' occurred due to the inadvertent opening of circuit breaker RPS-CB-7B during thermography of RPS-PP-C72/P001. The partial loss of RPS 'B' resulted in closure of primary containment isolation valves (PCIVs) in multiple systems. No plant parameters existed which would cause the opening of RPS-CB-7B or actuation of the primary containment isolation; therefore, this is considered to be an invalid actuation of a system listed in 10 CFR 50.73(a)(iv)(B). The closure of PCIVs were expected responses to the partial loss of RPS 'B'. Circuit breaker RPS-CB-7B was closed lo restore energy lo RPS 'B' at 1008 (PDT), containment isolation valves were opened, and the affected systems were returned to normal operating conditions for the current configuration per plant procedures. As indicated in 10 CFR 50.73(a)(1), in the case of an invalid actuation reported under 10 CFR 50.73(a)(2)(iv)(A), the licensee may, at its option, provide a telephonic notification lo the NRC Operations Center within 60 days of discovery of the event instead of submitting a written Licensee Event Report. This 60-day telephone notification is being made in accordance with 10 CFR 50.73(a)(1) for invalid actuations reported under 10 CFR 50.73 (a)(2)(iv)(A). This actuation was invalid since it was caused by maintenance activities and not the result of actual plant conditions warranting containment isolation. The following additional information is provided as specified in NUREG-1022: The following inboard containment isolation valves were actuated when personnel inadvertently bumped into RPS-CB-7B during the removal of a panel � RWCU-V-1 Reactor Water Cleanup Suction Inboard Isolation Valve � EDR-V-19 Drywell Equipment Drain Inboard Isolation Valve � FDR-V-3 Drywell Floor Drain Inboard Isolation Valve � RRC-V-19 Reactor Water Sample Inboard Isolation Valve � TIP-V-15 Traversing In-Core Probe Purge Isolation Valve All actuations occurred as designed upon the partial loss of RPS power. There were no actual safety consequences associated with this event since all affected equipment responded as designed. The NRG Residents have been notified. Notified R4DO (O'Keefe).

ENS 556821 January 2022 17:10:00ColumbiaNRC Region 4GE-5

The Licensee provided the following information via fax: During performance of a surveillance of the High Pressure Core Spray (HPCS) service water system on January 1, 2022, the HPCS system was declared inoperable for performance of the surveillance. During the surveillance, pump discharge pressure and flow were above the action range curve specified in the surveillance. For the given flow rate, pump discharge pressure was too high. This condition prevents declaring the HPCS service water system and HPCS system operable. The HPCS service water and HPCS systems remain inoperable. The station entered Technical Specification (TS) 3.7.2.A and TS 3.5.1.B at 0910 (PST) on January 1, 2022. In accordance with TS 3.5.1.B, the Reactor Core Isolation Cooling (RCIC) system was verified to be operable. TS 3.5.1 Action B provides a 14-day completion time to restore HPCS to an operable status. All other Emergency Core Cooling systems (ECCS) are operable. This event is being reported as an event or condition that could have prevented the fulfillment of a safety function credited for mitigating the consequences of an accident per 10 CFR 50.72(b)(3)(v)(D). The HPCS system is a single train system at Columbia. The NRC resident has been notified. The following additional information was obtained from the licensee in accordance with Headquarters Operations Officers Report Guidance: The licensee is investigating the cause of the high pump discharge pressure and verifying instrumentation accuracy.

  • * * RETRACTION ON 1/6/22 AT 1715 EST FROM CHASE WILLIAMS TO TOM KENDZIA * * *

This Notification is to retract EN 55682, Unplanned High Pressure Core Spray (HPCS) Inoperability. On 1/1/2022 at (1735 EST), Columbia Generating Station notified the NRC under 10 CPR 50.72(b)(3)(v)(D) of the inoperability of a single train of safety system (HPCS) for performance of the surveillance. During the surveillance pump discharge pressure and flow were above the action range curve specified in the surveillance. Engineering performed an analysis of this event and concluded the HPCS was operable during the event and would have performed its required safety function. The results of initial IST testing of HPCS-P-2 via OSP-SW/IST-Q703 on 01/01/22 resulted in measured parameters falling outside of the acceptable range specified for this pump. Systematic error was suspected as the cause of the failure and the test was reperformed following taking actions to eliminate the suspected systematic errors. The second performance of the test on 01/01/22 resulted in acceptable pump performance. Evidence exists that the initial performance of the test failed due to imprecise averaging techniques due to difficulties in averaging continuously changing values on the test instrument. The second performance of OSP-SW/IST-Q703 should be considered a successful test and the test of record as the systematic error was eliminated and measured parameters are considered valid. The NRC Resident Inspector has been notified. The HOO notified R4DO (Rolando-Otero).

ENS 555603 November 2021 19:31:00ColumbiaNRC Region 4GE-5On 11/03/2021 Columbia Generating Station concluded the results for refueling outage 24 (R24) and 25 (R25) Local Leak Rate Testing as-found data was incorrect. At 1231 PDT on November 3rd, 2021 Columbia Generating Station determined the local leak rate tests (LLRT) for the X- 25B containment penetration did not meet Technical Specification requirements for LLRT acceptance criteria. The incorrect LLRT data identified for residual heat removal (RHR) B Suppression Pool Spray containment isolation valve (RHR-V-27B) was from the previous two refueling outages (R24 on 5/22/2019 & R25 on 6/512021) at which time primary containment was not required to be operable. The corrected leakage assigned to the X-25 penetration also resulted in total Type B and C leakage summation exceeding the maximum allowable leakage rate for the primary containment (1.0 La) for R24 and exceeding 0.6La in R25. The valve was flushed and retested satisfactory prior to entering the mode of applicability. This event is being reported as an eight-hour, non-emergency notification per 10 CFR 50.72(b)(3)(ii)(A). There was no impact on the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
ENS 5542522 August 2021 15:30:00ColumbiaNRC Region 4GE-5On August 22, 2021, Columbia Generating Station determined that no more than approximately eight (8) gallons of silicone oil was inadvertently released into a plant service water system due to a failed heat exchanger on a plant installed air compressor. The plant service water system returns water to a water basin that contains at a minimum 300,000 gallons of water. The water basin is connected to the Columbia River via a blowdown line. Although not confirmed, it is suspected that an unknown quantity of silicone oil may have been released to the Columbia River. A visual inspection of the basin did not identify any oil sheen or film, and there are no additional actions needed to mitigate this issue. It does not appear the oil release poses a threat to human health or the environment, however because there could have been a discharge of an unknown quantity of silicone oil into the Columbia River this matter is immediately reportable under RCW 90.56.280 to the US Coast Guard National Response Center and Washington State Department of Ecology. This condition is being reported pursuant to 10 CFR 50.72(b)(2)(xi) for news release or notification of other government agencies concerning an event related to the health and safety of the public or protection of the environment. Notifications to off-site agencies were performed at 1825 PDT on 8/23/2021. The NRC resident has been informed.
ENS 5538529 July 2021 23:51:00ColumbiaNRC Region 4GE-5At 0922 PDT, on 07/28/21, the reactor building roof hatch was opened to support maintenance activities on the roof. Secondary containment differential pressure lowered and was recovered by the operating crew. Secondary containment differential pressure was maintained negative during the transient and was verified to have met technical specification requirements the whole time, however it was not identified at the time that the secondary containment was inoperable due to the roof hatch exceeding the allowable containment breech size and as such a TS 3.6.4.1.A entry was warranted. This report is being made pursuant to 10 CFR 50.72(a)(1)(ii) when it was identified that the secondary containment was inoperable while the roof hatch was open and a report should have been made under 10 CFR 50.72(b)(3)(v)(C) and (D) for loss of safety function. There were no radiological releases, system actuations, or isolations associated with this event. The licensee has notified the NRC Resident Inspector.
ENS 5521526 April 2021 22:11:00ColumbiaNRC Region 4GE-5A non-licensed employee supervisor had a confirmed positive for illegal drugs during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident has been notified.
ENS 546301 April 2020 19:02:00ColumbiaNRC Region 4A licensed operator had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified.
ENS 544668 January 2020 02:55:00ColumbiaNRC Region 4On January 7, 2020, Columbia Generating Station (CGS) experienced an equipment failure that resulted in a loss of the seismic assessment instrumentation. This is being reported as a major loss of emergency assessment capability in accordance with regulation 10 CFR 50.72(b)(3)(xiii). No other plant systems were affected. Compensatory measures have been implemented and will remain in place until the seismic system has been restored. The NRC resident has been notified. Licensee received a design basis earthquake alarm, but no other local indication of seismic activity, nor on the U.S. Geological Survey website. Licensee compensatory measures include local readings on seismic instrumentation.
ENS 5440925 November 2019 16:54:00ColumbiaNRC Region 4

EN Revision Text: TEMPORARY PROCESS RADIATION MONITORING SAMPLE CART NON FUNCTIONAL At 1245 PST, on November 23, 2019, the Turbine Building Process Radiation Monitoring Sample Rack (TEA-SR-26) was declared non-functional and taken out of service to perform planned preventive maintenance per procedure. The temporary sample cart was placed in service as an alternate method per plant procedures. At 0854 PST, on November 25, 2019, it was discovered that the temporary sample cart had a broken belt. At that time neither the Turbine Building Process Radiation Monitoring Sample Rack nor the temporary sample cart could be returned to service. At 1300 PST, on November 25, 2019, the temporary sample cart was returned to service following repairs. This restored the required compensatory measures for TEA-SR-26. This event is being reported as a major loss of assessment capability in accordance with 10 CFR 50.72(b)(3)(xiii). There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.

  • * * UPDATE ON 11/27/2019 AT 0655 EST FROM SEAN KEEHN TO BRIAN LIN * * *

At 2057 PST, on November 26, 2019, it was discovered that the temporary sample cart had lost power and was not in service. At this time, neither TEA-SR-26 nor the temporary sample cart were in service, this was a subsequent failure of the temporary sample cart, and at the time the station had been unsuccessful at restoring a reliable alternate sampling method following the failure that occurred at 0854 PST, on November 25, 2019. At 2350 PST, on November 26, 2019, the temporary sample cart was returned to service following repairs. This restored the required compensatory measures for TEA-SR-26. The NRC Resident Inspector will be notified. Notified the R4DO (Pick) via email.

ENS 5429225 September 2019 06:38:00ColumbiaNRC Region 4At 2338 PDT on September 24, 2019, the High Pressure Core Spray (HPCS) system was declared inoperable due to a leak on DSA-PCV-2C (2 inch Diesel Starting Air Pressure Control Valve). With one of two air headers isolated and being drained for maintenance, this leak caused the remaining starting air header for HPCS-GEN-DG3 (HPCS Diesel Generator) to lower to less than the operability limit. Upon declaring the HPCS system inoperable, TS 3.5.1 Action B was entered. In accordance with Action B, the Reactor Core Isolation Cooling (RCIC) system was verified to be operable. Action B provides a 14 day completion time to restore HPCS to an operable status. All other Emergency Core Cooling Systems (ECCS) were operable during this event. This event is being reported as an event or condition that could have prevented the fulfillment of a safety function credited for mitigating the consequences of an accident per 10 CFR 50.72(b)(3)(v)(D). The HPCS system is a single train system at Columbia. The leak was isolated and starting air header pressure restored to the HPCS diesel generator at 0104 PDT on September 25, 2019, and all associated Technical Specifications were exited. The NRC Resident Inspector was notified.
ENS 5411312 June 2019 03:04:00ColumbiaNRC Region 4A contract employee supervisor had a confirmed positive test for alcohol during a random fitness-for-duty test. The employee's access to the plant had been terminated. The NRC Resident Inspector has been notified.
ENS 538604 February 2019 22:03:00ColumbiaNRC Region 4A licensed reactor operator had a confirmed positive random fitness-for-duty drug test. The employee's access to the plant has been terminated. The NRC Resident Inspector has been notified.
ENS 537754 December 2018 08:00:00ColumbiaNRC Region 4On 12/4/2018 at 1340 (PST), Columbia entered a planned evolution to replace the seismic monitoring system. Use of the Modified Mercalli Intensity Scale has been implemented as a compensatory measure per station procedures. The expected duration of the replacement activity will exceed 72 hours, therefore, this is being reported as a major loss of emergency assessment capability in accordance with regulation 10 CFR 50.72(b)(3)(xiii). Compensatory measures will remain in place until the seismic system replacement has been completed. The NRC Resident Inspector has been notified.
ENS 5341018 May 2018 13:51:00ColumbiaNRC Region 4GE-5At 0651 (PDT) on May 18th, 2018, Columbia Generating station experienced a Main Transformer trip, that caused a Reactor Scram. Reactor Power, Pressure and Level were maintained as expected for this condition. MS-RV-1A (Safety Relief Valve) and MS-RV-1B (Safety Relief Valve) opened on reactor high pressure during the initial transient. MS-RV-1B appeared to remain open after pressure lowered below the reset point. The operating crew removed power supply fuses for MS-RV-1B and it currently indicates intermediate position. SRV (Safety Relief Valve) tail pipe temperatures indicate all valves are closed. Suppression pool level and temperature have remained steady within normal operating levels. All control rods inserted and reactor power is being maintained subcritical. RPV (Reactor Pressure Vessel) water level is being maintained with condensate and feed system with startup flow control valves in automatic. Reactor Pressure is being maintained with the Turbine Bypass valves controlling in automatic. The main condenser is the heat sink. No ECCS (Emergency Core Cooling Systems) systems actuated or injected; the EOC-RPT (End of Cycle-Recirculation Pump Trip) and RPS (Reactor Protection System) systems actuated causing a trip of the RRC pumps and a reactor scram. Core recirculation is being maintained with RRC-P-1A (Reactor Recirculation Pump) running. No release has occurred. At this time there will be no notifications to state, local or other public agencies. The NRC Senior Resident has been notified. The cause of the event is currently under investigation. Plant conditions are stable. The plant is in its normal electrical alignment and offsite power is available to the site.
ENS 5306813 November 2017 16:02:00ColumbiaNRC Region 4GE-5A licensed supervisor had a confirmed positive test for alcohol. The employee was escorted offsite and their plant access has been terminated and a five year denial placed in Personnel Access Data System (PADS). This is being reported per 10 CFR 26.719(b)(2)(ii). The NRC Resident Inspector has been notified.
ENS 529993 October 2017 15:00:00ColumbiaNRC Region 4GE-5On October 3, 2017, at 0800 PDT, Reactor Building (Secondary Containment) pressure momentarily rose above the Technical Specification (TS) limit. Secondary Containment was declared inoperable and TS Action Statement 3.6.4.1.A was entered. The pressure rise was due to unexpected isolation of an exhaust valve in the Reactor Building ventilation system during electrical switchgear inspections. The cause of the closure is still under investigation. The Control Room operators reopened the Reactor Building exhaust valve and pressure returned to within limits automatically. Secondary Containment was declared operable at 0802 PDT and TS Action Statement 3.6.4.1.A was exited. This condition is being reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and accident mitigation. The NRC Resident Inspector has been notified.
ENS 5296612 September 2017 19:28:00ColumbiaNRC Region 4GE-5On September 12, 2017, at 1228 PDT, Reactor Building (Secondary Containment) pressure momentarily rose above the Technical Specification (TS) limit. Secondary Containment was declared inoperable and TS Action Statement 3.6.4.1.A was entered. The pressure rise was due to unexpected isolation of the supply and exhaust valves in the Reactor Building ventilation system due to an electrical transient on the power panel feeding the valve operators' solenoid pilot valves during maintenance. The cause of the electrical transient is under investigation. The Reactor Building differential pressure controller restored the building pressure to within limits. The Control Room operators reopened the Reactor Building ventilation supply and exhaust valves. Secondary Containment was declared operable at 1228 PDT and TS Action Statement 3.6.4.1.A was exited. This condition is being reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and accident mitigation. The licensee notified the NRC Resident Inspector.
ENS 5291820 August 2017 23:05:00ColumbiaNRC Region 4GE-5

On August 20, 2017 at 1605 PDT, Columbia Generating Station was manually scrammed from 100 percent power due to a rise of Main Condenser back pressure. Manual scram of the unit is procedurally required upon a loss of Main Condenser back pressure. Preliminary investigations indicate that the Main Condenser air removal suction valve (AR-V-1) closed, resulting in the Condenser back pressure rising to within 1.0 inch Hg of the setpoint with reactor power greater than 25 percent. Further investigations continue. All control rods fully inserted. In addition to the closure of the air removal suction valve, one of two Reactor Feedwater startup flow control valves did not adequately operate to control Reactor vessel level and resulted in a high-level (Level-8) actuation tripping the Reactor Feedwater System. All other systems operated as expected. Reactor water level is currently being controlled manually with the start-up level control isolation valve. AR-V-1 has been manually opened with a jumper and temporary air supply. Reactor decay heat is being removed via bypass valves to the Main Condenser. This event is being reported under the following: 10 CFR 50.72(b)(2)(iv)(B), which requires a four-hour notification for any event or condition that results in actuation of the Reactor Protection System when the reactor is critical. The licensee notified the NRC Resident Inspector. The licensee plans to issue a press release.

  • * * UPDATE ON 8/24/17 AT 1937 EDT FROM MATT HUMMER TO DONG PARK * * *

The licensee is updating the notification to include an 8 hour notification under 10 CFR 50.72(b)(3)(iv)(A) for a specified system actuation due to a Level 3 isolation signal which occurred approximately 20 minutes after the scram. The licensee is currently in cold shutdown to repair the Reactor Feedwater startup flow control valve. The licensee has notified the NRC Resident Inspector. Notified R4DO (Farnholtz).

ENS 5291312 August 2017 07:00:00ColumbiaNRC Region 4GE-5Pursuant to 10 CFR 21, this is a non-emergency notification by Energy Northwest concerning a defect in General Electric (GE) Nuclear HMA124A2 relays received at Columbia Generation Station. On August 12, 2017, Energy Northwest completed a 10 CFR 21 evaluation of a condition associated with GE Nuclear HMA124A2 relays supplied by GE Hitachi Nuclear Energy Americas, LLC, and intended for use at Columbia Generating Station. The evaluation was performed to determine the applications where the relays were approved for installation, and where they were installed in the plant, and to determine if the failure of the relays could result in a Substantial Safety Hazard as defined In 10 CFR 21.3. Two of the HMA124A2 relays received had back plates that were mounted upside down, causing the terminals to not match the standard configuration. Although the internal wiring to the physical stud locations was correct, the numbering scheme embossed on the back plate did not match the correct configuration. With the incorrectly mounted back plate, the internal coil of the energizing circuit could be wired to the incorrect portion of the control circuitry, which would not energize when required and could result in the failure of a safety function. This deviation presents a Substantial Safety Hazard as defined In 10 CFR 21.3, as these relays were approved for use in safety related applications; however, there was no actual risk to plant safety since this deviation was recognized and resolved by station craft prior to installation of the relays. This condition is reportable under 10 CFR 21.21(d)(1) as a defect as defined in 10 CFR 21.3. The defective HMA124A2 relays were installed in the plant in the correct configuration with post-maintenance testing performed to ensure operability of the relays. The remaining HMA124A2 relays were examined and no additional defects were identified. GE Hitachi has been notified of the condition. The licensee will notify the NRC Resident Inspector.
ENS 5284811 July 2017 14:50:00ColumbiaNRC Region 4GE-5

This report is being made pursuant to 10 CFR 50.72(b)(3)(v)(D) as an event or condition that could have prevented fulfillment of a safety function. On July 11th, 2017, it was discovered that the flow indicating switch for the high pressure core spray (HPCS) minimum flow valve was providing unreliable indication. There was no flow through the line at the time the condition was discovered. This switch provides the flow signal to the HPCS minimum flow valve logic. The switch was declared inoperable and the required actions of Technical Specification 3.3.5.1 were entered. This condition could have prevented the HPCS system, a single train safety system, from performing its specified safety function. Troubleshooting is underway to determine the cause of and correct the condition. The licensee notified the NRC Resident Inspector.

  • * * RETRACTION FROM DAN SHARPE TO KARL DIEDERICH AT 1710 EDT ON 9/20/17 * * *

The condition reported in Event notification #52848 pursuant to 10 CFR 50.72(b)(3)(v)(D) has been evaluated, and determined not to have met the threshold for classification as an Event or Condition the Could Have Prevented Fulfillment of a Safety Function. Engineering analysis has concluded that the affected switch was capable of performing its required support function to provide the flow signal to the HPCS minimum flow valve logic. Thus, the HPCS system remained capable of performing its specific function for the identified condition. The NRC Resident Inspector has been notified. Notified R4DO (G. Miller).

ENS 5283027 June 2017 00:56:00ColumbiaNRC Region 4GE-5On June 26, 2017 at 1756 PDT, Reactor Building (Secondary Containment) pressure rose above the Technical Specification (TS) requirement multiple times from 1756 to 1800. Secondary Containment was declared inoperable and entry into Technical Specification Action Statement 3.6.4.1.A was made. There was a significant change in average wind speed and barometric pressure occurring at that time. At 1800 PDT, Secondary Containment pressure was restored to within limits and TS 3.6.4.1.A was exited. Environmental conditions have stabilized. The Reactor Building Differential Pressure controllers are working as designed. This condition is being reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and accident mitigation. The licensee has notified the NRC Resident Inspector.
ENS 5286925 May 2017 23:47:00ColumbiaNRC Region 4GE-5At 1647 (PDT) on May 25, 2017, during the performance of a post-maintenance test for replacement of a Reactor Pressure Vessel (RPV) low water level 3 indicator switch (MS-LIS-24A), a pressure perturbation in the common pressure reference line resulted in tripping of the RPV Level 2 instruments and an unplanned start of High Pressure Core Spray (HPCS) pump (HPCS-P-1) and its supporting emergency diesel (DG3). The Reactor Pressure Vessel was flooded up during the refueling outage, thus, the actuations of the HPCS pump and its supporting emergency diesel (DG3) were unplanned and invalid. The HPCS pump did not inject into the RPV due to the RPV level being above Level 8 which is an interlock to close the HPCS RPV injection valve (HPCS-V-4). During the event, the single train HPCS system initiated normally but did not inject into the reactor pressure vessel as expected due to flooded-up conditions of the reactor pressure vessel for refueling outage activities. The emergency diesel generator started normally in response to the initiation signal of HPCS. Both HPCS and the emergency diesel generator functioned successfully. All systems responded in conformance with their design and there was no safety significance associated with this event. At the time of the event, the licensee notified the NRC Resident (Inspector).
ENS 5261514 March 2017 23:00:00ColumbiaNRC Region 4GE-5Pursuant to 10 CFR Part 21, this is a non-emergency notification by Energy Northwest concerning a defect in Size 1 Freedom Series Starters with nominal 120 VAC coils manufactured by AZZ/NLI (Nuclear Logistics Inc.) used at Columbia Generating Station. On February 8, 2017 Energy Northwest was notified by NLI of a deviation associated with starter contactors used at Columbia that failed to close due to overheating of the starter coil. The coils that were provided were determined to not meet specified voltage ratings. The evaluation completed by Energy Northwest on March 14, 2017 concluded that the deviation did create a Substantial Safety Hazard, and is reportable under 10 CFR 21.21(d)(1) as a defect. A 30 day report will be issued by April 13, 2017 per 10 CFR 21.21(d)(4). The licensee performed a prompt operability assessment for the two starters currently installed. The licensee will notify the NRC Resident Inspector.
ENS 5251026 January 2017 02:36:00ColumbiaNRC Region 4GE-5On January 25, 2017, at 1836 PST, smoke was detected in the High Pressure Core Spray System (HPCS) diesel room with no indication of a fire. Investigation found the motor starter coil for DMA-FN-32 (Diesel Mixed Air Fan 32), HPCS diesel generator room normal cooling fan, failed. This fan is required for operability of the switchgear that powers the HPCS pump. The HPCS pump is currently inoperable due to maintenance being performed on other support systems. This condition is being reported under 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to mitigate the consequences of an accident. The licensee has notified the NRC Resident Inspector.
ENS 5244319 December 2016 07:20:00ColumbiaNRC Region 4GE-5

On December 18, 2016 at 2320 (PST), a leak was discovered on the High Pressure Core Spray (HPCS) system minimum flow line. The leak is located at a bolted flange downstream of the manual isolation valve HPCS-V-53. The location of the leak is not isolable from the suppression pool. This provides a direct path from inside the Primary Containment to the Reactor Building. High Pressure Core Spray system is a single train Emergency Core Cooling System (ECCS) system, therefore inoperability is reportable per 10 CFR 50.72(b)(3)(v)(D). Based on the location of the leak, Primary Containment integrity is compromised. Primary Containment was declared inoperable and is reportable per 10 CFR 50.72(b)(3)(ii)(A). The cause of the leak is under investigation. Actions are underway to cool down and enter MODE 4. The licensee has notified the NRC Resident Inspector.

  • * * RETRACTION FROM MATT HUMMER TO HOWIE CROUCH AT 2245 EDT ON 5/24/17 * * *

Engineering evaluations indicate that there was neither a High Pressure Core Spray (HPCS) system inoperability nor a condition that resulted in a significantly degraded principal safety barrier (Primary Containment). Therefore, this event does not meet the reporting criteria in 10 CFR 50.72(b)(3)(v)(D) and 10 CFR 50.72(b)(3)(ii)(A), and Event Notification# 52443 is being retracted. Bases for the retraction are: (1) Extent or accumulation of water flooding the HPCS room would not have prevented the system from fulfilling any of its designated safety functions, if the system had received a starting signal due to an emergency; and (2) the consequences of the HPCS Minimum Flow Line leak into the Reactor Building were within the dose limits and did not have a significant effect on Primary Containment integrity; therefore, the Primary Containment was degraded but operable. The licensee has notified the NRC Resident Inspector. Notified R4DO (Groom).

ENS 5244218 December 2016 19:24:00ColumbiaNRC Region 4GE-5On December 18, 2016 at time 1124 PST the plant experienced a full reactor scram. Preliminary investigations indicate that the scram was caused by a load reject from the Bonneville Power Administration (BPA) Ashe substation. Further investigations continue. The following conditions have occurred: Turbine Governor valve closure Reactor high pressure trip +13 inches reactor water level activations E-TR-B (backup transformer) supplying E-SM-7/SM-8 (vital power electrical busses) Complete loss of Reactor Closed Cooling (RCC) E-TR-S (Startup transformer) supplying SM-1/2/3 (non-vital power electrical busses) E-DG-1/2/3 (emergency diesel generators) auto start Low Pressure Core Spray (LPCS) and Residual Heat Removal (RHR) A/B/C initiation signals Main Steam Isolation Valves (MSIV) are closed Reactor Core Isolation Cooling (RCIC) RCIC and High Pressure Core Spray (HPCS) were manually activated and utilized to inject and maintain reactor water level. Pressure control is with Safety Relief Valves (SRV) in, manual. Level control is with RCIC and Control Rod Drive (CRD). RCIC has experienced an over speed trip that was reset so that level control could be maintained by RCIC. This event is being reported under the following: 10 CFR 50.72(b)(2)(iv)(A) which requires a 4 hour notification for Emergency Core Cooling System (ECCS) discharge into the reactor coolant system. 10 CFR 50.72(b)(2)(iv)(B) which requires a 4 hour notification for any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical. 10 CFR 50.72(b)(3)(iv)(A) which requires an 8 hours notification for actuation of ECCS systems. All control rods fully inserted. The NRC Resident Inspector has been informed. The licensee indicated that no increase in radiation levels were detected.
ENS 5238220 November 2016 22:02:00ColumbiaNRC Region 4GE-5On November 20, 2016 at 1402 PST, Reactor Building Exhaust Air Fan 1B, REA-FN-1B, failed to start in manual which caused the Technical Specification (TS) for secondary containment pressure boundary to not be met. The duration of the time that the secondary containment TS was not met was approximately less than one minute. REA-FN-1B was being started in manual during a shift of Reactor Building Ventilation to support a post-maintenance support task on REA-FN-1B. Secondary containment differential pressure was restored within the TS requirement of greater than or equal to 0.25 inch of vacuum water gauge by restarting Reactor Building HVAC Train A. The cause of REA-FN-1B failing to start is currently under investigation. This condition is being reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material and accident mitigation. The licensee has notified the NRC Resident Inspector.
ENS 522763 October 2016 17:08:00ColumbiaNRC Region 4GE-5On October 3, 2016, at 1008 PDT a Reactor Building Exhaust Valve (REA-V-1) unexpectedly closed, which caused the Technical Specification (TS) for secondary containment pressure boundary to not be met. The duration of time that the secondary containment TS was not met was approximately 4 minutes. Secondary containment differential pressure was restored within TS requirement of greater than or equal to 0.25 inches of vacuum water gauge at approximately 1012 PDT by manually starting Standby Gas Treatment (SGT) system (SYS) A. The cause of the REA-V-1 closure is currently under investigation. This condition is being reported under 10CFR50.72(b)(3)(v)(C) for an event or condition that could have prevented fulfillment of a safety function needed to control the release of radioactive material. The licensee has notified the NRC Resident Inspector.
ENS 5182628 March 2016 20:22:00ColumbiaNRC Region 4GE-5At 1322 PDT on Monday, March 28, 2016, Columbia Generating Station was manually scrammed from 100% thermal power due to the loss of Reactor Closed Cooling (RCC). Manual scram of the unit is procedurally required upon loss of RCC. The cause of the loss of RCC is being investigated. Regulation 10 CFR 50.72(b)(2)(iv)(B) requires reporting within 4 hours of any event or condition that results in actuation of the Reactor Protection System (RPS) when the reactor is critical. All control rods were fully inserted. Valve RWCU-V-4 automatically closed upon high water temperature due to loss of RCC flow. No other safety system actuations were reported. All systems operated as expected. Reactor decay heat is being removed via bypass valves to the Main Condenser. The station is in normal shutdown electrical lineup. The NRC Resident Inspector has been informed. No safety/relief valves lifted and no emergency core cooling systems injected following the reactor scram.
ENS 5173313 February 2016 18:00:00ColumbiaNRC Region 4GE-5On 2/10/2016 at 1000 PST, Columbia entered a planned evolution to perform channel functional tests on the RadWaste Building noble gas monitor (WEA-RIS-14). Compensatory measures were implemented per station procedures. The station is experiencing equipment issues and the monitor has not been restored within 72 hours (2/13/2016 at 1000 PST) from the start of the outage. The extended outage of this radiological monitoring instrument is, therefore, being reported as a major loss of radiological assessment capability in accordance with regulation 10 CFR 50.72(b)(3)(xiii). Compensatory measures will remain in place until the WEA instrument is restored. The NRC Resident Inspector has been notified. Note: Reactor Power is 75 percent due to a planned plant downpower for unrelated scheduled work with a planned return to 100 percent at 1900 PST on 2/14/16.
ENS 5156224 November 2015 21:30:00ColumbiaNRC Region 4GE-5At approximately 1100 PST, Columbia Generating Station (CGS) planned to make a non-required notification to Energy Facility Site Evaluation Council (EFSEC) regarding indications of two fuel defects. This condition has not affected full power operation at CGS, and there is no impact to the health and safety of the public or to the environment. CGS plans on making this notification to EFSEC on November 24, 2015 at 1330 PST. This condition is being reported pursuant to 10 CFR 50.72 (b)(2)(xi). The licensee notified the NRC Resident Inspector.
ENS 5152610 November 2015 04:40:00ColumbiaNRC Region 4GE-5At 2040 PST on 11/9/2015, Reactor Building (Secondary Containment) pressure increased to above the Technical Specification Surveillance requirement of 0.25 inches vacuum water gauge for approximately seven minutes. Operators took action to manually start Standby Gas Treatment System to restore Reactor Building pressure. This event is reportable as an event that could have prevented fulfillment of a safety function needed to control the release of radiation and mitigate the consequences of an accident. The cause of the event is under investigation. There were no radiological releases associated with the event. No safety system actuations or isolations occurred. The licensee notified the NRC Resident Inspector.
ENS 5122814 July 2015 06:39:00ColumbiaNRC Region 4GE-5

Reactor Building (Secondary Containment) pressure increased to above the Technical Specification Surveillance requirement of 0.25 inches vacuum water gauge for approximately 2 minutes during a planned surveillance test due to a subsequent failure of REA-FN-1A (Exhaust Fan) to manually start during restoration from the surveillance test. This event is reportable as an event that could have prevented fulfillment of a safety function needed to control the release of radiation and mitigate the consequences of an accident. Prior to taking test data the surveillance test directs declaring Secondary Containment inoperable in anticipation of potentially exceeding 0.25 inches vacuum water gauge reactor building pressure during the conduct of the surveillance. Consequently Technical Specification LCO 3.6.4.1.A was entered with a 4 hour completion time to restore Secondary Containment to an operable state. Upon failure of REA-FN-1A to start immediate actions were taken to close reactor building ventilation dampers and secure ROA-FN-1A (Supply Fan). Following closure of ventilation dampers and stopping ROA-FN-1A reactor building pressure was quickly restored to less than 0.25 inches vacuum water gauge with Standby Gas Treatment that was already in operation as part of the surveillance test. There were no radiological releases associated with the event. No safety system actuations or isolations occurred. The licensee notified the NRC Resident Inspector. Maximum Secondary Containment pressure noted was 0.1 inches positive water gage.

  • * * RETRACTION AT 1351 EDT ON 8/25/2015 FROM MATT HUMMER TO MARK ABRAMOVITZ * * *

Subsequent to the initial report, Columbia has since determined that per NUREG-1022 3.2.7 the event was not reportable as Secondary Containment was 'declared inoperable as a part of a planned evolution ... in accordance with an approved procedure and (Columbia's) TS (Technical Specifications).' No condition has been discovered that would have resulted in the system being declared inoperable prior to the surveillance. Therefore, this event is not considered to be a condition that could have prevented fulfillment of a safety function or a condition prohibited by TS and is not reportable to the NRC as a Licensee Event Report (LEA) per 10 CFR 50.73. The NRC Senior Resident Inspector will be notified. Notified the R4DO (Campbell).

ENS 512016 July 2015 21:20:00ColumbiaNRC Region 4GE-5A recent review of Fire Protection and Post Fire Safe Shutdown (PFSS) Programs at Columbia Generating Station (CGS) identified a potential unanalyzed condition with Multiple Spurious Operation (MSO) Scenario 2x. Review of the circuit design for High Pressure Core Spray (HPCS) HPCS-V-10, HPCS-V-11 and HPCS-V-15 identified that fire-induced circuit failure (hot shorts) on the OPEN function control circuits for each valve would create the flow path to potentially drain inventory from the suppression pool (SP). The normal operation of HPCS-P-3 (keep-fill pump) would allow additional inventory from the SP to be transferred to the CSTs (Condensate Storage Tank). If a fourth hot short is postulated, HPCS-P-1 would transfer inventory from the SP to the CST at a much faster rate. HPCS-V-11 was deactivated on 6/12/2015 due to a maintenance repair issue and will be left in the fully closed position. This plant alignment resolves current concern for MSO scenario 2x as fire-induced circuit damage cannot cause spurious opening of HPCS-V-11. However, with an incomplete analysis for MSO scenario 2x, compliance with PFSS MSO requirements would have been challenged from the completion of the MSO project (October 2012) up to June 2015. CGS is reporting this event as an unanalyzed condition in conformance with 10 CFR 50.72(b)(3)(ii)(B). Further analyses are being implemented to confirm the condition and to develop appropriate remedial actions. The licensee will notify the NRC Resident Inspector.
ENS 5118226 June 2015 05:00:00ColumbiaNRC Region 4GE-5At 2200 PDT during startup from refueling outage 22, it was discovered that both level instruments used in reactor protection system (RPS) trip system 'A' for initiation of a reactor scram on low reactor pressure vessel (RPV) level were observed to have failed high. This resulted in the inability to generate a full reactor scram on low level (+13 inches). All remaining RPV level indications demonstrated that level was being maintained within normal operating bands. This constitutes a condition that at the time of discovery could have prevented the fulfillment of the safety function of structures or systems that are needed to shut down the reactor. The RPS trip logic at Columbia consists of two trip systems, RPS trip system 'A' and RPS trip system 'B'. There are two level instrument channels in each trip system. Columbia utilizes a 'one-out-of-two taken-twice' trip logic to generate a full scram signal. At least one channel in both trip systems must actuate to generate a full scram signal. With both level instruments in RPS system 'A' failed high, the RPS trip logic was unable to generate a full scram. At 2246 (PDT) and in accordance with TS LCO 3.3.1.1 Condition C, a half scram was generated on RPS trip system 'A' to restore full scram capability. The cause of the failure of the two level instruments associated with RPS Trip system 'A' is under investigation. The level channels are being calibrated prior to changing to mode 1 (power operations). The licensee will notify the NRC Resident Inspector.
ENS 5109428 May 2015 05:17:00ColumbiaNRC Region 4GE-5A planned outage of the Division 2 medium voltage switchgear (SM-8) was initiated at 22:17 PDT on 5/27/15. The bus outage results in all area radiation monitors required for emergency classification being non-functional. Compensatory measure monitoring equipment has been established prior to the loss to provide alternate means of monitoring area radiation levels. The SM-8 outage window is scheduled to last 124 hours. Although the monitoring function is maintained by the compensatory monitoring equipment, the planned loss of area radiation monitors for greater than 72 hours is being reported as a major loss of emergency assessment capability in accordance with 10 CFR 50. 72(b )(3)(xiii). The NRC Resident Inspector has been notified.
ENS 5108622 May 2015 07:14:00ColumbiaNRC Region 4GE-5At 0014 PDT on 05/22/2015, Columbia experienced an unexpected momentary loss of SM-7, a Division 1 4.16 kV vital bus, resulting in a start of Emergency Diesel DG-1 . Additionally, under voltage circuitry prevented Standby Service Water pump 1A from starting to support DG-1 in response to the valid under voltage condition, and operators tripped the diesel at 0016 PDT. The SM-7 bus was reenergized by a 115 kV offsite source through backup transformer TR-B. The cause of this event was an inadvertent trip of under voltage circuitry while connecting test equipment in preparation for Diesel and Loss of Power logic testing. Division 1 was inoperable due to ongoing maintenance during the current refueling outage and was not being relied upon for decay heat removal or core circulation. Columbia is in Mode 5 with a coolant temperature of 96 degrees F, water level is at the normal refueling flooded level with fuel pool cooling gates removed. Division 2 is providing required electrical power and supporting components required for decay heat removal and inventory control. There was no impact to Shutdown Safety Assessment. The NRC Resident Inspector has been notified.
ENS 5102730 April 2015 01:11:00ColumbiaNRC Region 4GE-5At 1811 PDT on 04/29/2015, the station declared the RPIS system inoperable when a Control Room panel alarmed the loss of indication. The cause of the equipment loss is under investigation. This unplanned equipment outage is being conservatively reported as a major loss of assessment capability in accordance with 10 CFR 50.72(b)(3)(xiii). No other safety equipment has been impacted by this event and the plant continues normal operation. The NRC Resident Inspector has been notified.
ENS 510683 April 2015 07:00:00ColumbiaNRC Region 4GE-5On 4/21/2015, during performance of source check surveillance on the liquid effluent radiation monitor for the Plant Service Water (TSW), a non-radioactive system, it was discovered that the instrument was determined to be nonfunctional. It was determined on 4/25/15 that the failure was due to an incorrect 'as left' setting from testing conducted on 4/3/2015. The instrument was determined to be non-functional from the period 4/03/15 to 4/25/15 when the setting was corrected. On 5/12/15 it was recognized that because no compensatory measures were implemented during the time the instrument was non-functional that this condition constituted a major loss of radiation assessment capability which is reportable in accordance with 10 CFR 50.72(b)(3)(xiii). The NRC Resident Inspector will be notified.
ENS 5056923 October 2014 17:46:00ColumbiaNRC Region 4GE-5A planned outage for the Turbine Building Exhaust Air Radiation Indicating Switch (TEA-RIS-13) and the Turbine Building Process Radiation Monitoring Sample Rack (TEA-SR-26) for health inspection was initiated at 1046 PDT on 10/23/14. Due to maintenance retests taking longer than expected and in anticipation of possibly exceeding 72 hours for the planned outage, this event is being reported as a major loss of assessment capability under regulation 10 CFR 50.72(b)(3)(xiii). Compensatory measures have been implemented to obtain radiation readings from the associated effluent release pathway during the outage. Field team assessment function was unaffected and remains available. The Resident Inspector will be notified.
ENS 5038019 August 2014 14:33:00ColumbiaNRC Region 4GE-5This notification is being made due to a loss of emergency assessment capability in accordance with 10 CFR 50.72(b)(3)(xiii). At 0733 (PDT), on 08/19/2014, PRM-RE-18, Reactor Building Stack Monitor - Intermediate Range Detector, failed downscale. PRM-RE-1A and PRM-RE-1C, the Reactor Building Stack Monitor - low and high range detectors, both remain operable and fully functional. Compensatory measures are being implemented per plant procedures at this time. The NRC Resident Inspector has been notified.