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On October 3, 2017 at 0800 PDT, Secondary Containment (Reactor Building) became inoperable due to pressure increasing above the Technical Specification (TS) limit of -0.25 inches of water gauge (inwg). While the plant was at 100% power, a Reactor Building exhaust valve unexpectedly closed, resulting in a loss of Secondary Containment for approximately two minutes. Secondary Containment was declared inoperable and TS Action Statement 3.6.4.1.A was entered. The Control Room operators reopened the Reactor Building exhaust valve and pressure returned to within limits automatically. Secondary Containment was declared operable at 0810 PDT and TS Action Statement 3.6.4.1.A was exited. The event was reported under 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72 (b)(3)(v)(D) as Event Notification #52999.

The apparent cause of the event is a surface degradation on the lower stab of an electrical disconnect causing a momentary high resistance when the cubicle door is opened. This event occurred during performance of thermography in the cubicle.

On September 21, 2017 at 0800 PDT, Columbia Generating Station declared number 2 Diesel Generator inoperable for maintenance and entered Technical Specification Action Statement (TSAS) 3.8.1, Condition B for One Required Diesel Generator inoperable. At 0821 PDT and again at 1537 PDT Surveillance Requirement 3.8.1.1 was performed per action statement B.1. At 2315 PDT it was noted by operations that a page was missing from the surveillance procedure for both occurrences and determined that the action statement was not met within the required action time. Operations entered TSAS 3.8.1, Condition F for Required Action and associated Completion Time of Condition B not being met. AT 2321 PDT SR 3.8.1.1 was performed satisfactorily and Condition F was exited.

The apparent cause was a failure to page check the surveillance procedure prior to use. Initiatives have been developed to reinforce existing standards and improve human performance.

This event is reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) Operation or Condition Prohibited by Technical Specifications.

On June 6, 2017 at 1756 PDT hours Secondary Containment pressure exceeded the Technical Specification (TS) limit during a period of inclement weather. At 1756 PDT Secondary Containment was declared inoperable and operations personnel entered TS Action Statement 3.6.4. I .A and subsequently exited at 1800 PDT. Secondary Containment pressure was restored automatically by system response and operator action was not required.

The direct cause of the momentary loss of Secondary Containment was due to slow system response to maintain a vacuum in Secondary Containment during a period of inclement weather. The interim planned corrective action is to verify proper operation and tuning of the Secondary Containment instrumentation. Additionally Columbia Generating Station is pursuing the change to TS requirements by adopting TSTF-551, Revise Secondary Containment Surveillance Requirements.

This condition is being reported under 10 CFR 50.73(a)(2)(v)(C) and 10 CFR 50.73(a)(2)(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 to mitigate the consequences of an accident.

On November 20, 2016 at 1402 PST, Secondary Containment (NH) (Reactor Building) became inoperable due to pressure increasing above the Technical Specification limit of -0.25 inches of water gauge (inwg). While the plant was ascending in power, the Reactor Building exhaust air fan unexpectedly failed to start in manual during post-maintenance testing. Prior to this event, Reactor Building Heating, Ventilation and Air Conditioning (VA) (HVAC) System A was running. Per station procedures, System A was stopped and System B was to start. The fan's failure to start resulted in no Reactor Building fans running, and increased Reactor Building pressure.

For a time period of less than one minute, Secondary Containment pressure was not maintained less than or equal to -0.25 inwg.

Immediate recovery actions by Operations personnel included manually starting Reactor Building HVAC System A, which quickly restored Secondary Containment pressure to less than or equal to -0.25 inwg at 1403 PST. While TS limits were exceeded for this short time period, the resulting pressure excursion was bounded by analytical results; and thus, there were no safety consequences for this condition. This event was reported under reporting criteria 10 CFR 50.72(b)(3)(v)(C) and 10 CFR 50.72(b)(3)(v)(D) as Event Notification #52382.

The cause of the exhaust fan's failure to start was a faulty control switch for the fan. Corrective actions for this event include replacement of the control switch. There were no other event-related equipment malfunctions.

On November 9, 2015 at 20:40 PST, Secondary Containment (Reactor Building) became inoperable due to pressure increasing above the Technical Specifications (TS) limit of -0.25 inches water gauge (inwg).

At the time of the event the Division 2 Reactor Building Heating, Ventilation and Air Conditioning System (HVAC) was controlling Secondary Containment differential pressure. Power supply E-E/S-299 then failed, causing Division 2 Secondary Containment Pressure controller to lose power. This resulted in the Division 2 Reactor Building Exhaust Fan flow being reduced, causing Secondary containment pressure to rise above TS limit of -0.25 inwg.

Operations personnel manually started the Division 2 SGT lead fan to restore negative pressure. The lead fan operated at max flow (due to the failure of E-E/S-299) resulting in the restoration of Secondary Containment pressure to within TS limits.

The Division 1 HVAC was manually started, allowing Operations personnel to manually secure the Division 2 SGT lead fan and maintain Secondary Containment pressure.

The direct cause for the loss of E-E/S-299 was due to an incorrect lug size installed in the fuse block during initial construction.

Current procedures are adequate to prevent a similar error.

26158 R6 NRC Form 366 (01-2014) APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by intemet e-mail to Inf000llects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

The condition reported by this LER was an expected condition, which was the result of planned activities in support of a routine refueling outage. As described in the LER, the U.S. Nuclear Regulatory Commission (NRC) provided enforcement guidance, applicable to boiling water reactor licensees, that allows the reported condition.

Although this allowance is provided by the NRC's enforcement guidance, the planned activities are still reportable in accordance with 10 CFR 50.73(a)(2)(i)(B) as a condition prohibited by Technical Specifications (TS).

Between May 13, 2015 and June 13, 2015, Columbia Generating Station (Columbia) performed Operations with the Potential for Draining the Reactor Vessel (OPDRV) activities while in Mode 5 without an operable secondary containment, as expected and allowed by NRC Enforcement Guidance Memorandum (EGM) 11-003, Revision 2.

Although EGM 11-003, Revision 2, allows implementation of interim actions as an alternative to full compliance, this condition is still considered a condition prohibited by Technical Specification (TS) 3.6.4.1. The OPDRV activities were planned activities that were completed under the guidance of plant procedures and work instructions and are considered to have low safety significance based on the interim actions taken. Since these actions were deliberate, no cause determination was necessary. A license amendment request will be submitted following NRC approval of the Technical Specification Task Force (TSTF) traveler associated with generic resolution of this issue.

26158 R6 NRC Form 366 (01-2014) APPROVED BY OMB: NO. 3150-0104 EXPIRES: 01/31/2017 Reported lessons learned are incorporated into the licensing process and fed back to industry.

Send comments regarding burden estimate to the FOIA, Privacy and Information Collections Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by intemet e-mail to Inf000llects.Resource@nrc.gov, and to the Desk Officer, Office of Information and Regulatory Affairs, NEOB-10202, (3150-0104), Office of Management and Budget, Washington, DC 20503. If a means used to impose an information collection does not display a currently valid OMB control number, the NRC may not conduct or sponsor, and a person is not required to respond to, the information collection.

Description::== FACILITY NAME ==

M. Hedges

• TELEPHONE NUMBER (Include Anon Cod.) 509-377-8277

13. COMPUTE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT

CAUSE SYSTEM COMPONENT MANU- FACTURER

REPORTABLE

TO EPIX CAUSE SYSTEM COMPONENT

MANU-

FACTURER

REPORTABLE

TO EFIX

14. SUPPLEMENTAL REPORT EXPECTED

0 YES (ft yes, complete 15. EXPECTED SUBMISSION DATE) .:. NO 14. EXPEL MONTH DAY r YEAR

SUBMISSION

DAT3 ., .. . 4.

ABSTRACT (Limit to I it spaces, i.e., approximately 15 single-spaced typewritten On March 12, 2014, it was identified that thr: manhole covers (E10, El 1, and E 15) for vaults containing 4160 volt electric cables were missing the hold down bolts. The hold down bolts are required as part of the tornado missile barrier for the manhole cover for the underground electric vault. It was later determined that the hold down bolts for manhole cover E 1 / (Division 2 Service Water) had been identified as missing since September 6, 2013.

When the bolts were identified as missing on September 6, 2013, the manhole cover and bolts were not recognized as a tornado missile barrier; because this information was not available in routinely used databases and procedures. No compensatory action was taken until March 12, 2014, when large concrete blocks were placed on top of the manholes to prevent the covers from potential removal in the event of a tornado. The degraded missile barrier is considered to have rendered the Division 2 Service Water system inoperable from September 6, 2013, to March 12, 2014. This is reportable as a condition prohibited by Technical Specifications.

26158 R6 NRC Form 366 (01-2C14) APPROVED DV ON& NO. 31104104 - UMW: 01l3I/2017 Elrodad Laden par respire lo comply sib Ilia mandelory colecim request P3 hours.

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NRC FO

U.S. NUCLEAR REGULATORY COMMISSION UCENSEE EVENT REPORT (LER)

CONTINUATION SHEET

Columbia Generating Station 05000 397 & LER NUMBER 3 P AG E 2 OF 2014 - 0

PLANT CONDITIONS

Columbia was operating at 100% power. There were no inoperable plant systems at the time of discovery that contributed to this event.

EVENT DESCRIPTION

On March 12, 2014, it was identified that three manhole covers (E10, El 1, and E 15) for vaults containing 4160 volt electric cables (CBI.) were missing the hold down bolts. The electric cables in vaults El0 and Eli support the Division 2 Service Water (BI) system. The electric cables in vaults EIS s the Division 3 Service Water system. The hold down bolts are required as part of the tornado missile barrier for the manhole cover for the underground electric vault. It was later determined that the hold down bolts for manhole cover Ell (Division 2 Service Water) had been identified as missing in two condition reports on September 8, 2013, and again on December 3, 2013. When Operations performed an immediate operability determination for the September and December 2013 condition reports, the manhole cover and bolts were not recognized as a tornado missile barrier; therefore, no compensatory action was taken until March 12, 2014.

The degraded missile barrier is considered to have rendered the Division 2 Service Water system inoperable from September 6, 2013, to March 12, 2014. This is reportable as a condition prohibited by Technical Specifications.

IMMEDIATE CORRECTIVE ACTION

It was verified through the Weather Service that no tornados were predicted for our area in the next 24 hours. Large concrete blocks were placed over the manhole covers on March 12, 2014, to prevent the cover from lifting in the event of a tornado.

The information fields in the master equipment list for the applicable manhole covers were completed identifying them as a tornado missile barrier.

CAUSE

The information in this section is based on the preliminary results of a root cause evaluation. If any significant changes in the cause or corrective actions are made in the final evaluation, a supplement will be submitted for this report.

The direct cause for the missing hold down bolts was not determined.

The root cause of the failure to recognize the manhole cover as a tornado barrier was that station procedures that implement the process to establish quality classifications for safety-related systems, structures, and components (SSCs) did not ensure accurate information was available in a timely manner for these components.

There are multiple methods available for determining the safety significance of a degraded component; however., the computerized master equipment list is typically the preferred method. The equipment plant numbers (EPNs) for the manhole covers had been entered into master equipment list in 2012, but no action was taken to complete the remaining data fields for the components to kientify that the manhole covers fulfilled a tornado barrier function, and have the information verified and approved. The master equipment list that station personnel used identified these manhole covers as nonsafety-related.

26158A A3 NA'; FORM 366A 01-"eC14) IL LER NUMENEPI 5 PAGE 2. DOCKET 1. FACILITY NAME Columbia Generating Station YEAR OF 3 A 0014 - 003 -0

NRC FORM

014014) LICENSEE EVENT REPORT (LER) U.S. NUCLEAR REGULATORY COMMISSION

CONTINUATION SHEET

In the immediate rability determination process for the two Condition Reports in 2013, Operations personnel did not have information readily available to them to determine that the manhole cover was a tornado missile barrier. Most plant personnel, including Operations, did not recognize that the information in the computer master equipment list for the manhole covers was not at an approved status and should not be used. The manhole covers did not have any label indicating that it was a tornado missile barrier. Plant drawings did not identify the manhole covers as tornado missile barriers. Additionally, the station barrier impairment procedure did not list the manhole covers as a tornado missile barrier.

FURTHER CORRECTIVE ACTION

Work requests were initiated to repair/replace the missing bolts for the manhole covers.

Revise Engineering procedures to provide clear direction to establish Quality Classifications for safety-related SSCs within the Master Equipment List within a specific time frame. Ensure that procedures include timeliness requirements for establishing and upgrading/downgrading EPNs for installed plant equipment.

Apply a marking on the manhole covers that identify these covers as a tornado missile barrier.

Revise the station barrier impairment procedure to identify manhole covers as a tornado missile barrier.

ASSESSMENT OF SAFETY CONSEQUENCES

No actual tornados occurred during the time of interest. The Division 2 Service Water system remained capable of fulfilling its safety function during this time period. Additionally, at least one other division of Service Water was available during this time period (September 6, 2013 to March 12, 2014) to be able to fulfill the safety function; therefore, the actual safety consequence of this issue was minimal.

SIMILAR EVENTS

There have been no similar events at Columbia Generating Station in the last three years.

ENERGY INDUSTRY IDENTIFICATION SYSTEM (ENS) INFORMATION CODES EIIS s a are bracketed 'Mere applicable in the narrative.

NERGY

.!‘‘ORT1:1--"T er 914)

On January 7, 2013, Columbia was operating at 100% power. At 1427 PST both doors of the 501 elevation airlock entrance of the Reactor Building were simultaneously opened for a short period of time. This was the result of the failure of the interlock between the outer door (R304), and the inner door (R305).

Maintenance personnel were moving scaffolding through the Reactor Building outer security door when an equipment operator opened the inner door to exit the Reactor Building. This equipment operator immediately closed the inner door and contacted the Main Control Room. The outer door was key locked closed until corrective actions could be implemented.

Having a condition where both doors in a Reactor Building airlock were opened simultaneously while not undergoing a planned evolution for maintenance or surveillance testing, results in an unintended entry into Technical Specification (TS) 3.6.4.1 Secondary Containment due to a failure to satisfy Surveillance Requirement (SR) 3.6.4.1.3.

It was determined that this condition resulted in a loss of safety function (Secondary Containment) and was reported to the NRC (Event Notification 48656) at 1629 PST on January 7, 2013.

2615B R5 Ur.

• 4-';

On June 28, 2011, while the plant was in Mode 5 for refueling outage R20, Columbia Generating Station (Columbia) failed to enter a required Technical Specifications (TS) Action Statement while performing control rod exercises. During stroke time testing, control rod 34-47 displayed an erroneous indication. Upon initial withdrawal, the four rod display showed an alternating indication of "XX" (meaning the reed switch was not open during movement) and "00" (full in indication) requiring the position indication to be declared inoperable per TS 3.9.4. Control rod 34-47 was subsequently fully inserted and testing resumed on other rods contrary to the required action statement of TS 3.9.4. Upon discovery of the noncompliance, the TS required actions were subsequently performed and the failed reed switch replaced. The Control Room Supervisor and Shift Manager did not verify the required action statements specified in the TS and Bases as required. This was determined to be the apparent cause. A contributing cause included not performing all of the required steps in the procedure for control rod stroke time testing. Columbia has had no previous occurrences of a failure to enter the required action statement of TS 3.9.4.

This condition is reportable under 50.73(a)(2)(i)(B) as a condition prohibited by TS.

26158 R5

the #2 high pressure turbine bearing was reported to the main control room. As directed by procedure, a manual scram was inserted at 1952.

The in-service turbine lube oil vapor extractor system did not provide enough differential pressure to prevent lube oil from leaking out of the bearing pedestal. The fire occurred when the leaking lube oil came into contact with a hot pipe causing the oil to flash.

The root causes were an out of calibration pressure switch and the integrated system knowledge of the main turbine lube oil exhauster system by Operations and Engineering was weak. The pressure switch has been replaced. Additional corrective actions taken to prevent recurrence include revisions to station procedures to ensure that the turbine lube oil vapor extractor system pressure is monitored via independent instruments during routine operator rounds as well as after any system manipulation. In addition, improvements in training fOr Operations and Engineering are planned to increase overall system knowledge.

No similar events have been reported by Energy Northwest.

26158 R4 Columbia Generating Station

On July 30, 2004, Columbia Generating Station (Columbia) was in Mode 1 with the reactor operating at -100 percent power. At 09:23 PDT, the reactor automatically scrammed when the reactor protection system (RPS) received trip signals from three out of four reactor steam dome pressure - high instrument channels.

The high reactor steam dome high-pressure condition was a result of a turbine governor valve (MS-V GV/1) drifting closed. The turbine governor valve drifted closed due to a failure of a bypass capacitor on a NUCANA Servo Driver (NSD) circuit board associated with the governor valve electro-hydraulic control system. The failed capacitor was a monolithic ceramic capacitor. This capacitor provides high frequency bypass filtering for the onboard power supply at one of the operational amplifiers. The capacitor failed with low resistance which caused a high current load that eventually caused the circuit board protective fuse to clear and the closure of MS-V-GV/1.

This event posed no threat to the health and safety of the public. The NSD circuit board was replaced and a detailed failure analysis will be performed on the failed circuit board.

26158 R2