|Entered date||Site||Region||Reactor type||Event description|
|ENS 50468||25 February 2020 09:32:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||During a review of INPO Event Report 14-33, Direct Current Circuits Challenge Appendix R Fire Analysis, it was determined that portions of the control circuits for the Turbine Generator DC Emergency Lube Oil Pump and the Emergency DC Seal Oil Pump are not properly fused to prevent overload and possible secondary fires. The review found that a fire at the motor starter cabinet in the turbine building could cause specific smart hot shorts that could cause overheating of the control cable and result in secondary fires outside the turbine building. Based on this information, it was determined that this condition is unanalyzed and is potentially reportable per 10 CFR 50.72(b)(3)(ii)(B). Hourly fire watch compensatory measures are in place in the affected areas of the Turbine Building. The presence of compensatory measures in addition to automatic fire detection and suppression in these fire areas ensures protection of the equipment. The licensee has notified the NRC Resident Inspector.|
|ENS 54508||1 February 2020 23:06:00||Wolf Creek||NRC Region 4||At 1845 CST on 2/1/2020, during surveillance testing (STS PE-015, Containment Purge Valve Leakage Test) containment leakage in excess of Technical Specification requirements was observed. A Technical Specification required shutdown was initiated at 2030 CST and Mode 3 was achieved at 2154 CST. All systems functioned as required during and following shutdown. The unit is proceeding to Mode 5. The licensee notified the NRC Resident Inspector.|
|ENS 54109||11 June 2019 17:03:00||Wolf Creek||NRC Region 4||At 1324 CDT, on 6/11/19, Coffey County Emergency Management issued the following alert: The Civil Authorities have issued a Nuclear Power Plant Warning for Coffey, KS beginning at 1323 CDT and ending at 1423 CDT (WIBW radio AM/FM). Coffey County Emergency Management Required Weekly Test. A press release is planned to notify residents that the warning was only a test. There was no impact to the health and safety of the public as a result of this event as the offsite response capabilities remain functional. The site is operating with no emergency conditions present. This event is being reported under 10 CFR 50.72(b)(2)(xi), as an inadvertent notification of the IPAWS (Integrated Public Alert Warning System) system. A press release is planned. The NRC Resident Inspector has been notified.|
|ENS 54087||24 May 2019 17:12:00||Wolf Creek||NRC Region 4||At 1310 CDT on 5/24/2019, Wolf Creek experienced a loss of offsite power to the safety-related NB02 bus, due to an external fire on a bushing on the startup transformer. The NB02 bus was reenergized when the 'B' Emergency Diesel Generator started and the output breaker automatically closed. The shutdown sequencer automatically started equipment as expected. Due to the undervoltage condition on the NB02 bus, an AFAS-T (Auxiliary Feedwater Actuation Signal) signal was generated which started the turbine driven auxiliary feedwater pump. Turbine load was reduced to maintain reactor power less than 100% in response to the start of turbine driven and 'B' motor driven auxiliary feedwater pumps. The fire was extinguished using a fire extinguisher at 1320 CDT. The unit is stable at 97% power. The NB02 bus remains on the 'B' Emergency Diesel Generator (EDG). The other EDG is operable in standby. The NRC Resident Inspector was notified.|
|ENS 53842||22 January 2019 14:40:00||Wolf Creek||NRC Region 4||On January 22, 2019, 0723 CST, the Contracts group called and reported to FFD (fitness for duty), that a box of candy was received from a supplier vendor that may contain alcohol. Upon investigation of the candy with the manufacturer, pieces of the candy contain 20-30mg of Alcohol after the chocolate is cooked. The Contract offices are located in the Protected Area and this incident is being reported under 10 CFR 26.719. No for-cause testing was performed based on the consumption of the candy. No safety related work was performed by the individuals who may have consumed the candy. The box of candy was removed from the site. The licensee notified the NRC Resident Inspector.|
|ENS 53647||5 October 2018 09:59:00||Wolf Creek||NRC Region 4|
EN Revision Text: UNPLANNED LOSS OF THE ASSESSMENT CAPABILITY DUE TO TECHNICAL SUPPORT DIESEL At 05:52 CDT on 10/5/2018, the (Wolf Creek Nuclear Operating Corporation) (WCNOC) Technical Support Center (TSC) Diesel fuel oil transfer pump would not run. There was ongoing modification to the facility Halon system at the time. The modification process had included a jumper to the fuel oil transfer pump to allow it to continue to be available. This issue was discovered during testing as the modification was progressing. The pump was verified to function on 10/4/2018 by normal operations rounds. If an emergency is declared requiring the TSC activation during the time the TSC diesel is non-functional, the TSC will be staffed and activated using existing emergency planning procedure. If offsite power is lost, the TSC will relocate to the Alternate TSC using existing emergency planning procedures. There was no impact to the health and safety of the public or plant personnel. The NRC Resident Inspector has been notified.
Event Notification (EN) 53647, made on October 8, 2018, is being retracted because during the time that the TSC Diesel fuel oil transfer pump was not available, normal power was continuously available. The Alternative TSC was also available. Consequently, the condition did not meet the criteria for a 8-hour notification per 10 CFR 50.72(b)(3)(xiii) for any event that results in a major loss of emergency assessment capability, offsite response capability, or offsite communications capability (e.g., significant portion of control room indication, Emergency Notification System, or offsite notification system). The NRC Resident Inspector has been notified of the Event Notification retraction. Notified R4DO (Pick).
|ENS 53095||28 November 2017 10:01:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
(On) Monday, 11/20/17, (the licensee) received a call from the MRO (Medical Review Officer) staff that the Opiate blind submitted on 11/14/17 did not test as expected. The confirmatory test was positive for codeine and morphine but negative for 6-acetylmorphine. (The licensee) requested a retest by the MRO to the laboratory. The MRO staff contacted the provider of the blind specimens for documentation of the blind analysis. The lab was requested on 11/21/17 to perform the retest by the MRO. (On) 11/27/17, the results from the lab on the retest were virtually the same as the original test result. The lab's Certifying Scientist provided a letter documenting their findings. The MRO staff informed us (Wolf Creek) and we requested copies of all documentation from the provider of the blinds, the lab and any notes from the MRO staff. Informed Superintendent Access Screening of the test results. (The licensee) contacted two plants to verify reportability under 10 CFR 26.719. (The licensee) initiated CR 00117707 to document the occurrence. Superintendent contacted licensing and management. The licensee will inform the NRC Resident Inspector and R4 NRC Security Inspector.
This event was reported under 10 CFR 26.719(c)(3). Further review shows that this event should have been reported under 10 CFR 26.719(c)(1), which only required a Licensee Event Report, not an Event Notification. This notification is retracted. The licensee will notify the NRC Resident Inspector. Notified R4DO (Hipschman) and FFD Group via email.
|ENS 52666||5 April 2017 16:32:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
Both Emergency Diesel Generators (EDGs) have truck connections connected to transfer lines that are potentially not compliant with general design criteria. A potentially unanalyzed condition exists due to threat of tornado generated missiles. While in Mode 1 at 100% power, the Control Room was notified that the outdoor portion of the line upstream of JEV0001, EMERG FUEL OIL STORAGE TK A TRUCK CONN ISO, and the outdoor portion of the line upstream of JEV0002, EMERG FUEL OIL STORAGE TK B TRUCK CONN ISO, potentially have not been reviewed to meet general design criteria. No major equipment was out of service. No systems were required to respond to this event. The unit remains in Mode 1 at 100% power. The NRC Senior Resident Inspector has been notified. Compensatory measures have been established IAW (in accordance with) EGM 15-002. The Unit entered Tech Spec 3.8.1 Condition B and D for approximately 45 minutes until compensatory measures were put into effect. The licensee identified this condition during a design review and is currently identifying long-term corrective actions.
The Unit entered Tech Spec 3.8.1 Condition B and F, not Tech Spec 3.8.1 Condition B and D mentioned earlier. Notified R4DO (Vasquez).
|ENS 52399||29 November 2016 06:19:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||While operating in mode 1 at 100% rated thermal power an approximately 150 gallon oil spill occurred in the switchyard. Westar Energy personnel were performing corrective maintenance on the station's #6 transformer that required cleaning the oil. The #6 transformer was out of service at the time. The oil was being transferred to a group of hold up tanks. One of the tanks overflowed before the next tank could be placed in service. This resulted in the spill of approximately 150 gallons of UNIVOLT N 61 B, electrical insulating oil onto gravel and soil. The spill has been stopped. The oil had recently been sampled and there were no detectable polychlorinated biphenyls, PCBs. A clean up plan is being developed. Condition Report 00109759 has been generated. The acting NRC Senior Resident has been informed. The reportable quantity for the oil is 5 gallons. The licensee has notified the State of Kansas Department of Health and Environment and the National Response Center.|
|ENS 52299||18 October 2016 06:11:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||This report is being made pursuant to 10 CFR 26.719(b). At 0305 (CDT) today an unknown substance was identified inside the protected area (inside an emergency light fixture in the emergency escape hatch for containment). At 0456, local law enforcement determined (the substance) was likely a prohibited substance (marijuana). The substance was obviously very old, so is surmised to be from a preoperational period and unable to be positively tested. The item (a bag of leafy material, round metal tube, rope with washer, light bulb) was under the control of the site security department upon discovery and was turned over to local law enforcement for disposal. The licensee notified the NRC Resident Inspector.|
|ENS 52218||2 September 2016 11:29:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
While operating in MODE 1 at 100 percent rated thermal power and placing Excess Letdown in service for Reactor Coolant System (RCS) leak detection, RCS operational leakage exceeded 1 gpm (gallon per minute) unidentified leakage as identified by performing RCS Water Inventory Balance using the Nuclear Plant Information System Computer. This required the entry into Technical Specification (TS) Limiting Condition of Operation (LCO) 3.4.13 Condition B at 0808 (CDT) on 9/2/16. The associated action is to place the unit into Mode 3 in 6 hours. Trending of containment sump level indicates the leakage is inside containment with the exact location within containment unknown. Containment inspection is being performed to try and identify the source of Reactor Coolant System leakage. NRC Resident Inspector has been notified. Re-alignment of the Letdown System back to its normal arrangement has subsequently reduced RCS leak rate to 0.521 gpm at 0652 CDT on 9/2/16. Unusual or Not Understood - Leak Location is not known at this time. Maximum leak rate recorded was 1.358 gpm. The leak was first discovered at 08/31/16 at 1519 CDT. Safety Related Equipment not operational - Reactor Vessel Level Indicating System (TS 3.3.3).
Wolf Creek Nuclear Operating Corporation is retracting the 10 CFR 50.72(b)(2)(i) notification based on subsequent review of the event. The calculation of unidentified leak rate which triggered entry into the Mode 3 Required Action Statement was performed immediately after placing RCS Excess Letdown in service. An evaluation of the leak rate calculation determined that the leak rate was invalid due to performance of the RCS water inventory balance during non-steady state operating conditions. This was contrary to the requirements of TS Surveillance Requirement 126.96.36.199, as this test was performed while charging and letdown flows were being stabilized following the alignment of excess letdown. A walk down of the Excess Letdown system while in-service determined no leakage. Subsequent RCS water inventory balances performed with Excess Letdown in service under steady state operating conditions while in Mode 3 at normal operating pressure and temperature determined the maximum calculated unidentified leak rate was 0.675 gpm. After the plant entered Mode 3 a non-RCS pressure boundary leak was identified during equipment walk downs on a seal weld from the reactor vessel head core exit thermocouple nozzle assembly 77. The leakage did not impact the ability to shut down the unit. No TS limits were exceeded during this event. Therefore, the plant shutdown to investigate and correct leakage past the seal weld of a threaded connection does not meet the reporting requirements of 10 CFR 50.72. The NRC Resident Inspector has been notified. Notified the R4DO (Kramer).
|ENS 52184||16 August 2016 15:43:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||On 8/16/2016, while operating at 100% in Mode 1, routine testing of the off-site sirens for Wolf Creek was scheduled. The county dispatcher was unable to actuate any sirens. The dispatch supervisor was contacted to ensure there was not a personnel qualification issue. Both the dispatcher and the supervisor were unable to actuate any sirens, either manually or using the normal computer controls. Coffey county personnel, assisted by Wolf Creek personnel, determined that a battery had failed causing a fuse to blow and de-energizing the equipment needed to actuate the sirens. The battery has been replaced, the fuse has been replaced, and the system has been tested satisfactorily. The emergency sirens were restored to service at 12:20 CDT 8/16/2016. NRC resident has been notified. No plant systems were affected by this failure of notification equipment. The plant remained at 100% power Mode 1 throughout this event.|
|ENS 51297||6 August 2015 20:53:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
Technical Support Center (TSC) Air Conditioning (AC) unit is out of service. Due to expected high temperatures in the upcoming days, there exists the potential for the TSC to become nonfunctional. This could result in a reduction in Emergency Plan Response Capability. The Alternate TSC is available for use in the event of an emergency and would be staffed and activated using existing EP (Emergency Preparedness) procedures and checklists. The licensee has notified the NRC Resident Inspector.
As of 0700 (CDT), 8/17/15, the TSC is fully functional, the HVAC system has been restored to 100 percent capacity. NRC Resident Inspector has been notified." R4DO (HAGAR) has been notified.
|ENS 51074||15 May 2015 23:48:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
Class 1E A/C Unit SGK05A cools safety related electrical train 'A' and was found tripped at 2148 (CDT). As a result, the following supported safety related electrical equipment were declared inoperable: 4.16 KV Bus NB01, 480 Volt Buses NG01 and NG03, 120 volt Instrument AC Inverters and Buses NN11, NN13, NN01 and NN03, 125 VDC Chargers and Buses NK11, NK13, NK01 and NK03. T/S 3.0.3 was entered from T/S 3.8.7 due to two out of four 120 volt AC Inverters (NN11 and NN13) being inoperable. All electrical systems listed above remain available but are declared inoperable due to inadequate room cooling capability. Plant shutdown to mode 5 commenced at 2244 (CDT). No major equipment is out-of-service. All systems have functioned normally. Plant is currently at 99% with power ramping down. Plant must be in mode 3 by 0448 CDT. No compensatory measures have been established. The NRC Resident Inspector has been notified. See EN #51071 for an earlier T/S required shutdown required at 0436 CDT on 5/15/15, due to the same conditions.
For both EN 51071 and 51074, the low lube oil pressure switch tripped the SGK05A unit. Oil pressures were verified to be normal and the SGK05A unit was successfully started. The plant shutdown each time was terminated. A fault in the Electronic Oil Pressure control which monitors the low lube oil pressure switch was identified. A jumper has been installed that bypasses the oil switch while maintenance is being conducted. The unit was declared functional but degraded. Indication of low oil pressure is still provided. The licensee notified the NRC Resident Inspector. Notified the R4DO (Okeefe).
|ENS 51071||15 May 2015 07:22:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||Class 1E A/C Unit SGK05A cools safety related electrical train 'A' and was found tripped at 0436 (CDT). As a result, the following supported safety related electrical equipment were declared inoperable: 4.16 KV Bus NB01, 480 volt Buses NG01 and NG03, 120 volt Instrument AC Inverters and Buses NN11, NN13, NN01 and NN03, 125 VDC Chargers and Buses NK11, NK13, NK01 and NK03. T/S 3.0.3 was entered from T/S 3.8.7 due to two out of four 120 volt AC Inverters (NN11 and NN13) being inoperable. All electrical systems listed above remain available but are declared inoperable due to inadequate room cooling capability. Plant shutdown to mode 5 commenced at 0530 (CDT). No major equipment is out-of-service. All systems have functioned normally. Plant is currently at 95 % power ramping down. Plant must be in mode 3 by 1136 CDT. No compensatory measures have been established. The NRC Resident Inspector has been notified.|
|ENS 51036||3 May 2015 12:56:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||On 5/3/2015 during power ascension following Refueling Outage 20, Steam Generator 'C' water level increased rapidly, causing a Feedwater isolation on high Steam Generator water level and an associated Turbine trip. The reactor was subsequently manually tripped. At the start of the event, reactor power was approximately 22%. Plant staff was in the process of transferring from Main Feedwater Bypass Feed Regulating Valve control, used for low power control, to Main Feedwater Regulating Valve control as part of power ascension. When the Main Feedwater Regulating Valve for 'C' Steam Generator (AEFCV-530) was opened, it went to about 80% open, causing an overfeed of the 'C' Steam Generator. High Steam Generator water level in 'C' Steam Generator initiated an automatic Feedwater Isolation Signal, automatic Turbine Trip and automatic trip of the operating main feed pump. The operating crew initiated a manual reactor trip. The Auxiliary Feedwater System automatically initiated as part of the plant response to the feedwater system transient. The plant is presently stable in Mode 3. All equipment functioned normally, except the 'C' Main Feedwater Regulating Valve (AEFCV0530) which did not function to properly control Steam Generator level. This valve did function as designed to close on the Feedwater Isolation Signal. NRC Resident Inspector has been contacted.|
|ENS 50772||28 January 2015 08:56:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||At 0535 CST on 1/28/15, control room staff identified that valve EJHV8716A, RHR A To SIS (Safety Injection System) Hot Leg Recirc Loops 2&3 (isolation valve), had been closed per clearance order C20-D-EJ-A-005 to support maintenance on the A RHR system. Closing valve EJHV8716A placed Wolf Creek in TS 3.0.3. At 0550 CST on 1/28/15, power was restored to valve EJHV8716A and the valve was opened, allowing the unit to exit from TS 3.0.3. Subsequent reviews of clearance order C20-D-EJ-A-005 identified that valve EJHV8809A had been energized and closed per direction of the clearance order. TS 3.0.3 was reentered at 0635 CST due to discovery of this condition. At 0650 CST, valve EJHV8809A was opened and deenergized allowing exit from TS 3.0.3. The licensee notified the NRC Resident Inspector.|
|ENS 50744||19 January 2015 14:24:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
The missile door (door 33012) protecting Class 1E Engineered Safety Features (ESF) buses NB01/NB02 switchgear rooms was discovered misaligned on its hinge and stuck partially open and not capable of being closed. The missile door has since been repaired and closed. Technical Specification (TS) 3.8.9, 'Distribution Systems- Operating,' was declared not met and Condition F entered when the immediate operability determination identified that buses NB01 and NB02 were inoperable. Condition F of TS 3.8.9 requires immediate entry into Limiting Condition for Operation (LCO) 3.0.3. LCO 3.0.3 was entered at 1100 CST and subsequently exited when the missile door was repaired at 1118 CST. The unit was in and still is in MODE 1 at 100% power. No actions were initiated to commence a unit shut down. The NRC resident inspector was contacted regarding this event. All systems functioned as expected.
The licensee is retracting this event based on the following: An engineering evaluation concluded that the weather conditions during the period of the event did not result in the threat of a tornado. Given that the weather during the event would not have presented a valid threat of a tornado, the stuck open missile door would not have prevented the ESF busses and the DGs (Diesel Generators) from performing their specified safety function. The ESF busses and the DGs were considered OPERABLE but degraded. This is analogous to Example 4 in RIS 2001-09, 'Control of Hazard Barriers', with the exception that this event did not occur as a result of planned maintenance or a plant modification. As such, this event has been determined to not be reportable per 10 CFR 50.72(b)(3)(v)(D). The licensee has notified the NRC Resident Inspector. Notified R4DO (Gepford).
|ENS 50628||19 November 2014 16:42:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||On 11/19/2014, Wolf Creek determined that the alternative shutdown procedure for responding to a fire in the control room does not address all potential operating modes of the credited emergency diesel generator. During the 2014 Triennial Fire Protection Inspection, it was postulated that a loss of offsite power following a fire in the control room would cause the Train B emergency diesel generator (EDG) to start and load to the bus. The fire is also postulated to cause damage to the Train B essential service water (ESW) pump control circuit and prevent the pump from automatically starting and cooling the EDG. Additionally, the fire is postulated to cause spurious operation of another large load that is not normally sequenced onto the bus following a loss of offsite power. This postulated scenario loads the EDG to approximately 53% of its rated load without cooling. This scenario was not considered when developing the control room fire response strategy. Preliminary calculations show that operators have 3.6 minutes to establish cooling prior to the EDG tripping on high jacket water temperature. Performance timing determined that operators would establish cooling in approximately 10 minutes. Based on this information, it was determined that this condition is unanalyzed and is potentially reportable per 10 CFR 50.72(b)(3)(ii)(B). An hourly fire watch compensatory measure is in place in the control room, consistent with procedural requirements for a Post Fire Safe Shutdown circuit analysis deficiency. The licensee has notified the NRC Resident Inspector.|
|ENS 50407||27 August 2014 12:24:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||This notification is being made in accordance with 10 CFR 50.72(b)(3)(xiii) due to a loss of communications capability. On August 27, 2014 at 0805 hours CDT the internal phone system, Emergency Notification System (ENS), and Emergency Response Data System (ERDS) became nonfunctional because of a power supply failure. The ERDS has been restored to service and work is currently in progress to restore the internal phone system and ENS. It has not been determined at the time of this notification as to when the internal phones system and ENS will be restored to a fully functional status. The NRC Resident Inspector has been informed.|
|ENS 50047||20 April 2014 19:58:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||A leak was discovered in the area of EPV0109, COMBINED SI/RHR (Safety Injection/Residual Heat Removal) TO ACCUMULATOR D OUTLET LINE VENT. The leak rate was estimated at 2.5 gallons per hour. The plant is in Mode 5, RCS (Reactor Coolant System) depressurized. This leak is considered a material problem that causes abnormal degradation of or stress upon the reactor coolant system pressure boundary, reportable in accordance with 10CFR 50.72(b)(3)(ii)(A). Efforts are underway to characterize the leak and plan for repairs. The leak has been secured after realigning RHR cooling from the B to the A train. The Resident Inspector has been notified. The cause of the leak is being investigated.|
|ENS 49980||1 April 2014 10:06:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||At approximately 0616 CDT on April 1, 2014, a supplemental employee at Wolf Creek developed a personal medical condition. Wolf Creek Emergency Medical Technicians on site responded and an ambulance transported the individual to an offsite hospital. The individual was located in one of the office areas inside the protected area. The offsite hospital declared the individual deceased upon arrival on April 1, 2014. The individual was outside the Radiological Controlled Area. No radioactive material or contamination was involved. This notification is being performed in accordance with 10 CFR 50.72(b)(2)(xi). The NRC Resident Inspector has been notified. The licensee will notify the State and Coffey County.|
|ENS 49627||13 December 2013 13:40:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||At 1106 (CST), the control room was informed that a diesel fuel spill to the environment was a reportable event. Earlier in the day, a container tipped over in the bed of a truck eventually spilling diesel fuel onto the ground inside the owner controlled area. Approximately 2 and one half gallons spilled out. The lid of the container was apparently defective. No fuel oil made contact with any surface water. The area was cleaned up. The Kansas Department of Health and Environment and the National Response Center were notified. The NRC Resident Inspector has been notified.|
|ENS 49533||13 November 2013 11:42:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||Approximately 10 gallons of fuel oil was spilled from excavation equipment onto the ground inside the owner controlled area. Notifications will be made to the National Response Center and the Kansas Dept. of Health and Environment. Cleanup by on-site personnel is in progress. No fuel oil made contact with any surface water. NRC resident inspector has been notified (by the licensee).|
|ENS 49448||18 October 2013 13:47:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||Wolf Creek has commenced a plant shutdown in accordance with Technical Specifications. The A train class 1E electrical equipment air conditioning unit was declared non-functional due to a possible failed oil pressure sensor. This failure could prevent the (AC) unit from performing its required function over its required mission time, as required by Technical Specifications 3.8.4, 3.8.7, and 3.8.9. The following safety related electrical equipment was declared inoperable: 4.16KV bus NB01; 480 volt AC buses NG01 and NG03; 120 volt instrument AC inverters and buses NN11, NN13, NN01 and NN03; 125 VDC chargers and buses NK11, NK13, NK01 and NK03. Technical Specification 3.0.3 was entered at 1141 CDT on 10/18/2013 from Technical Specification 3.8.7 due to two out of four 120 VAC inverters (NN11 and NN13) being inoperable. Plant shutdown to Mode 5 commenced at 1211 CDT. All electrical systems listed above remain available but are declared inoperable due to inadequate room cooling capability. No major equipment is out of service. No switchgear room temperature limits were challenged. The NRC Resident Inspector has been notified. See event notifications; EN #49339, EN #49126, and EN #49008 for similar events.|
|ENS 49423||9 October 2013 22:47:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||A review of industry operating experience with respect to fire induced damage to unfused Direct Current (DC) ammeter circuits in the control room has determined that the condition described below is applicable to Wolf Creek Nuclear Generating Station. This condition results in an unanalyzed condition with respect to 10CFR50 Appendix R analysis requirements. The original plant wiring design did not include overcurrent protection features to limit the fault current in these circuits. The wiring design for the ammeters contains a shunt in the current flow from each NK direct current (DC) battery or charger. Two leads run from the shunt to a current meter in the main control room (MCR). These leads are tied to the positive polarity of the NK battery system. The ammeter wiring attached to the shunt is not overcurrent protected. It is postulated that a fire could cause one of these ammeter wires to short to ground at the same time the fire causes another DC wire from the opposite polarity on the same battery to also short to ground. This would cause a ground loop through the unfused ammeter cable. This event could result in excessive current flow (heating) in the ammeter wiring to the point of causing a secondary fire in the raceway system. The secondary fire could adversely affect safe shutdown equipment. Reference Palo Verde plant event #49411. A Breech Authorization with compensatory Control Room hourly fire watch for this issue is in place and will remain in effect until this deficiency is resolved. This condition has been discussed with the Resident Inspector. Similar Events #49422 and #49419|
|ENS 49126||17 June 2013 14:37:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||Class 1E A/C Unit SGK05A cools safety related electrical train 'A' and was declared non-functional at 1111 hours. As a result, the following supported safety related electrical equipment was declared inoperable: 4.16 KV Bus NB01, 480 volt Buses NG01 and NG03, 120 volt Instrument AC Inverters and Buses NN11, NN13, NN01 and NN03, 125 VDC Chargers and Buses NK11, NK13, NK01 and NK03. T/S 3.0.3 was entered from T/S 3.8.7 due to two out of four 120 volt AC Inverters (NN11 and NN13) being inoperable. All electrical systems listed above remain available but are declared inoperable due to inadequate room cooling capability. Plant shutdown to mode 5 commenced at 1125 hours. No major equipment is out-of-service. All systems have functioned normally. Plant is currently at 55% power ramping down. Plant must be in mode 3 by 1811 CDT. No compensatory measures have been established. The NRC Resident Inspector has been notified.|
|ENS 49065||23 May 2013 18:25:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||A non-licensed, supervisory employee had a confirmed positive for alcohol during a random fitness-for-duty test. The employee's access to the plant has been terminated. The licensee has notified the NRC Resident Inspector.|
|ENS 49008||6 May 2013 20:16:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||Class 1E Air Conditioning Unit SGK05A cools safety related electrical Train 'A' and was declared non-functional at 1733 hours. As a result, the following safety related electrical equipment was declared inoperable: 4.16 KV Bus NB01; 480 volt buses NG01 and NG03; 120 volt Instrument AC inverters and buses NN11, NN13, NN01 and NN03; 125 VDC chargers and buses NK11, NK13, NK01 and NK03. T/S 3.0.3 was entered at 1733 from T/S 3.8.7 due to two out of four 120 volt AC inverters (NN11 and NN13) being inoperable. Plant shutdown to Mode 5 commenced at 1801 hours. All electrical systems listed above remain functional but are declared inoperable due to inadequate room cooling capability. The licensee plans on performing a controlled plant shutdown using normal rod insertion following approved plant procedures. Per the licensee, Mode 3 conditions must be met by 0033 CDT 5/7/2013 and Mode 5 conditions must be met by 0033 CDT 5/8/2013. The licensee notified the NRC Resident Inspector.|
|ENS 48914||11 April 2013 16:47:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
The fire started at 1455 CDT in the turbine building southeast stairwell and on the auxiliary boiler room roof. Fire fighting efforts continue as fire exists inside the wall between the turbine building and the auxiliary boiler room. The licensee notified the NRC Resident Inspector, state, and local governments. Notified DHS, FEMA, and the NICC.
* * * UPDATE FROM WARREN BRANDT TO PETE SNYDER AT 0100 EDT ON 4/12/13 * * *
Wolf Creek declared a NOUE at 15:10 CDT on 4/11/13 due to a fire that started at 14:55 (CDT) in the Turbine Building SE stairwell and on the Auxiliary Boiler room roof. The fire was extinguished at 15:19 (CDT), and cool to the touch at 16:48 (CDT). No offsite fire response support was required. The fire did not impact any safety related equipment. The NOUE was terminated at 17:03 CDT 4/11/13. The cause of the fire is under investigation. Notified R4DO (Deese), NRR EO (Monninger), IRD (Marshall), DHS, FEMA and NICC (via email).
Update to Termination of NOUE due to Fire on roof of Auxiliary Boiler. Wolf Creek declared a NOUE at 15:10 CDT on 4/11/13 due to a fire that started at 14:55 (CDT) in the Turbine Building SE stairwell and on the Auxiliary Boiler room roof. The fire was extinguished at 15:19 (CDT), and cool to the touch at 16:48 (CDT). The Offsite Fire Department was called and responded but their support in fire suppression was not required, they did assist in clean up and fire investigation efforts. The fire did not impact any safety related equipment. The NOUE was terminated at 17:03 CDT 4/11/13. The cause of the fire is under investigation. Notified R4DO (Deese), NRR EO (Monninger), IRD (Marshall) via email.
|ENS 48820||13 March 2013 03:11:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
At 0149 CDT on 3/13/2013, Wolf Creek declared an Unusual Event due to inoperability of both on-site emergency diesel generators. While the A-EDG (Emergency Diesel Generator) was out of service due to planned maintenance, the B-EDG experienced a loss of control power. The cause is currently under investigation. Offsite power is available and providing electrical power to the Unit. The licensee notified state and local agencies and the NRC Resident Inspector. Notified DHS, FEMA, DHS NICC and NuclearSSA (email).
Repairs are complete on the 'B' EDG (Emergency Diesel Generator). The 'B' EDG has been tested and restored to operable status at 0221 (CDT) on 03/14/2013. The 'A' EDG remains out of service for scheduled maintenance. NUE (Notification of Unusual Event) terminated at 0239 CDT on 03/14/2013. The licensee notified state and local agencies and will notify the NRC Resident Inspector. Notified the R4DO (Powers), IRD (Grant) and NRR (Lubinski). Notified DHS, FEMA, DHS NICC and Nuclear SSA (email).
|ENS 48802||2 March 2013 00:25:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
On 3/1/2013 at 2242 CST, Wolf Creek Unit 1 declared a Notification of Unusual Event (NOUE) due to both Emergency Diesel Generators (EDG) being unavailable: With the 'A' EDG out of service for planned maintenance, the 'B' EDG was discovered to have high governor oil level and was declared inoperable at 2235 CST. The governor oil level was adjusted and the 'B' EDG was declared operable at 2307 CST. The NOUE was terminated on 3/21/2013 at 2321 CST. Normal offsite power was maintained to the plant and no offsite assistance was requested. The licensee notified state and local agencies and the NRC Resident Inspector. Notified DHS, FEMA, DHS NICC and NuclearSSA (email).
Further evaluation by the Engineering department determined that the 'B' EDG was available with the high governor oil level. Testing was performed at an offsite facility, which confirmed that the 'B' EDG was capable of performing its specified safety function with the as-found oil level. As a result, the condition has been determined to not be reportable per 10 CFR 50.72(a)(1)(i). The licensee will notify the NRC Resident Inspector. Notified R4DO (Drake), NRR EO (Skeen) and IRD MOC (Grant).
|ENS 48733||8 February 2013 11:50:00||Wolf Creek||NRC Region 4||A hydraulic oil line break occurred on a crane inside of the protected area. The break resulted in a 2-gallon spill of hydraulic oil. Wolf Creek has notified the National Response Center and Kansas Department of Health and Environment. The oil spill is being cleaned up by our environmental group. The licensee has notified the NRC Resident Inspector.|
|ENS 48134||25 July 2012 22:14:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
At 1602 (CDT), Engineering personnel notified the control room that during review of a pipe stress calculation it was identified that non-conservative or incorrect methodologies were used in the calculation. This calculation was for a modification to install four; 3 (inch) drain lines between the Essential Service Water (ESW) (safety) and the Service Water (SW) (non-safety) in 1991. A preliminary ME101 stress analysis performed, which corrects the above-identified discrepancies, indicates that the pipe stresses at the drain line weldolet connection exceed the ASME code of record allowable stresses by approximately 50%, when the revised Stress Intensification Factor (SIF) is applied. This modification affected both trains (A & B) ESW trains. The normal system alignment uses the SW water to supply the ESW, then during accident conditions the SW and ESW systems isolate from each other so that two redundant separate train isolation valves isolate the ESW system. These 3 (inch) drain lines are located in the section of piping that is isolated from the ESW and SW systems. At the time of notification 'A' ESW was isolated from SW and 'B' ESW was in normal system alignment. 'B' ESW was declared inoperable and action was taken to separate the SW and ESW and isolate the 3 (inch) drain valves. With this action complete the non-conforming components have been removed from service and OPERABILITY of the ESW has been restored. This condition is been reported per 10 CFR 50.72(b)(3)(ii)(B). The NRC Resident Inspector has been notified.
Further engineering evaluation determined that the four drain lines (3-inch) between the Essential Service Water (ESW) (safety) and the Service Water (SW) (non-safety) were found to be within the allowable limits for operability and are acceptable. As a result, the condition has been determined to not be reportable per 10 CFR 50.72(b)(3)(ii)(B). The NRC Resident Inspector has been notified. Notified R4DO (Miller).
|ENS 47998||6 June 2012 05:19:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
Wolf Creek commenced a nuclear plant shutdown in accordance with Technical Specifications. Engineering analysis has determined that with one non-functional Class IE A/C unit, there is inadequate cooling available to support electrical power systems required by Technical Specifications (TS) 3.8.4, 3.8.7, 3.8.9, during all postulated conditions. Actions are currently underway to restore the non-functional Class IE A/C unit to a functional status. The non-functional Class IE A/C unit had a clogged oil pump strainer. Per TS 3.0.3, Wolf Creek began reducing power and was at 89% power at the time of the report. The licensee has notified the NRC Resident Inspector.
The A Class IE A/C unit was restored to functional at 6/6/2012 0505 CDT. The plant shutdown was terminated at 87 percent power. Actions are underway to restore the unit to 100 percent power. Notified R4DO (Gepford).
|ENS 47590||13 January 2012 16:05:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
At 1403 CST, Wolf Creek experienced a reactor trip due to loss of power in the switchyard. At 1415 CST, Wolf Creek declared a Notification of Unusual Event (NOUE) when it was determined that the switchyard would not be restored within 15 minutes. All systems functioned as expected in response to this event and both Emergency Diesel Generators started and energized the safety-related buses. The plant is currently stable in Mode 3 and investigation into the cause for loss of power in the switchyard is underway. During the trip, all rods inserted into the core. No primary relief valves lifted as a result of the transient. Decay heat is being removed via the atmospheric steam dumps with auxiliary feedwater supplying the steam generators. The plant is stable at NOP/NOT. No safety significant equipment is reported out of service. The licensee has notified state and local governments and the NRC Resident Inspector.
At 1709 CST, the licensee exited the NOUE when power was restored to the east bus from offsite. Additionally, the licensee is reporting a loss of safe shutdown capability in accordance with 10CFR50.72(b)(3)(v)(A) due to the initial loss of offsite power. The licensee has notified state and local governments, the NRC Resident Inspector, and will be issuing a press release on the event. Notified R4DO (Powers), IRD (Marshall), NRR (Cheok), FEMA (Burckart) and DHS (Hill).
|ENS 47453||17 November 2011 17:17:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||A notification was made to the National Response Center and the Kansas Department of Health and Environment of a 7-10 gallon release of diesel fuel oil to the environment. The leak originated from a temporary diesel fueled heater in place for freeze protection for a temporary fire pump. The fuel oil was not released to surface water, and has been isolated. The NRC Resident Inspector has been notified.|
|ENS 47412||3 November 2011 19:06:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||During the 2011 Triennial fire protection inspection, it was determined that the off normal procedure for control room evacuation due to fire has two defects. It does not adequately protect the steam generators from overfilling and possibly damaging the turbine driven auxiliary feedwater pump. In addition it does not protect the reactor coolant system pressurizer from filling to above 100% indicated water level, possibly causing the primary system to go solid. Both of these issues are results of inadequate assumptions used in the Post Fire Safe Shutdown Analysis of a fire in the Control Room. Compensatory measure of hourly fire watch for the control room is in place. The procedure for control room evacuation due to fire is being revised to include compensatory actions that will address the above events. The NRC Resident Inspector has been notified.|
|ENS 47154||15 August 2011 13:10:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||On 8/11/2011 at 1145 CDT the Turbine Driven Auxiliary Feedwater pump was declared inoperable due to oil sample results indicating high particulate (ISO Solid Contamination Code above the Action Limit IAW I-ENG-004) in the turbine lube oil. The action limit is 19/16 and the sample result was 23/21. The ISO Solid Contamination Code is a measure of particle count and size. The same sample was analyzed for metal particulate concentration and results were satisfactory. Efforts have been underway to determine the source of the contaminate and to restore the turbine lube oil to within specifications. On 8/14/2011 at 0945 CDT NRC Region IV granted a Notice of Enforcement Discretion NOED beginning at 1145 CDT on 8/14/2011 to expire at 1145 CDT on 8/15/2011. Cleaning efforts have been completed. Current sample results indicate acceptable levels. A Basic Engineering Disposition has been issued supporting the sample results and basis for operability. Technical Specification required shutdown per TS 3.7.5 condition C.1 and C.2 was initiated at 1055 CDT on 8/15/2011. The Turbine Driven Auxiliary Feedwater Pump was declared operable at 1203 CDT on 8/15/2011 and the power reduction was halted at 82% Rated Thermal Power (RTP). Power ascension to 100% RTP was commenced at 1209 CDT on 8/15/2011. The licensee has notified the NRC Resident Inspector.|
|ENS 47076||20 July 2011 16:06:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||On July 20, 2011 at 1315 hours it was determined that a design deficiency at the Wolf Creek Nuclear Operating Corporation (WCNOC) constituted a fire protection program concern which could adversely affect the ability to achieve and maintain safe shutdown in the event of a control room fire. In the event of a postulated control room fire, a normally closed valve (EFHV0060) on the Essential Service Water (ESW) system return from the Component Cooling Water (CCW) heat exchanger could spuriously open. If this occurs, the flow balance in the ESW system would be affected and cooling flow to other essential components could be reduced to below the minimum required flow. Present system operability is not affected as there has been no occurrence of a fire in the Control Room and compensatory actions are in place to detect and mitigate the effects of a fire in the Control Room. An hourly fire watch is currently in place in the control room and will remain in place until this issue is resolved. In addition to the hourly fire watch, alternate shutdown procedure OFN RP-017 is being revised to include interim compensatory actions to deenergize, and verify closed, valve EFHV0060. This event is being reported in accordance with 10 CFR 50.72 (b)(3)(ii)(B) and 10 CFR 50.72 (b)(3)(v)(A) as an unanalyzed condition that significantly degrades plant safety. A follow-up licensee event report will be made in 60 days. The NRC Resident Inspector has been notified.|
|ENS 46990||26 June 2011 18:00:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
6/26/11 at 1609 CDT, the reactor was manually tripped due to the trip of the 'B' Main Feed Pump while operating in Mode 1 at approximately 82% reactor power. The unit was increasing power to 95% after the current refuel outage. The cause of the trip of the 'B' Main Feed Pump is not known at this time. All equipment functioned normally as expected. The investigation into the cause of the 'B' Main Feed Pump trip is ongoing at this time. Current plant status is Mode 3. The NRC Senior Resident has been contacted. All rods fully inserted upon reactor trip. The unit is stable with Auxiliary Feedwater supplying the Steam Generators. Decay heat is being removed to the Main Condenser via steam dumps. The electrical system is in a normal post-trip alignment. The licensee characterized the reactor trip as uncomplicated.
A valid Auxiliary Feed(water) actuation signal (occurred) due to trip of both of the Main Feed pumps from a turbine trip and low steam generator levels. This is reportable under 10CFR50.72 (b)(3)(iv)(A), 8-hour report. All auxiliary feed pumps started and operated as expected. The licensee will notify the NRC Resident Inspector. Notified R4DO (Deese).
|ENS 46909||1 June 2011 17:07:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
At 1315 (CDT), while in Mode 3 at normal operating pressure and 552?F, both trains of Component Cooling Water (CCW) were inoperable due to indications of voiding. The 'A' Train CCW had been declared inoperable at 1000 (CDT) when review of pump test data indicated a potential void and Technical Specification LCO 3.7.7, 'Component Cooling Water (CCW) System,' Condition A was entered. At 1315 (CDT), indications of voiding were identified in the common service loop piping, which was aligned to the 'B' Train CCW. The 'B' Train CCW was declared inoperable and the plant entered LCO 3.0.3 due to both CCW Trains being inoperable. At 1410 (CDT) plant cool down to Mode 4 was commenced. The 'A' Train CCW has subsequently been vented and void volume is currently within allowable limits for operability. However, further evaluation of this voiding is underway prior to declaring the 'A' Train CCW operable. The licensee has notified the NRC Resident Inspector.
The licensee is retracting this event based on the following: Further engineering evaluation concluded the amount of gas ingested by the 'A' CCW pump would not cause any degradation to the pump. The remainder of the gas in the system was less than the acceptance criteria for the CCW system. The 'A' CCW train was capable of performing its specified safety function and therefore would have been considered operable. The condition would not have prevented the CCW System from fulfilling its safety function and would not be reportable under 10 CFR 50.72. The licensee has notified the NRC Resident Inspector. R4DO (Gaddy) notified.
|ENS 46877||24 May 2011 13:40:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||At 11:20 (CDT) on 5/24/11, the unit, while in Mode 4, had a reactor trip and Aux Feedwater actuation/Feedwater Isolation Signal due to lo-lo level on 'B' Steam Generator. Reactor Trip breakers were closed to support DRPI (Digital Rod Position Indication) testing. Steam Generator levels were being maintained approximately 30% to support Aux Feedwater pump full flow testing. The trip occurred at 23.5% level in the steam generator. Reactor trip breakers opened and the motor-driven auxiliary feedwater pump fed the steam generators. The feedwater isolation valves fully closed. No other actuations occurred. Operators are in the process of resetting plant conditions to support completion of the testing in progress at the time of the trip. The licensee has notified the NRC Resident Inspector.|
|ENS 46720||4 April 2011 01:51:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
(Three) of the (eleven) emergency notification sirens became non functional when a severe thunderstorm passed through the area. The Coffey County Sheriffs office reported that they received telemetry notifications that the sirens were out of service. Pursuant to 50.72(b)(3)(xiii), the loss of alert systems (sirens) greater than one hour require an 8-hour notification. The exact cause of the siren loss (i.e. power outage, downed pole, etc) is not known and, as of the time of reporting, the duration of the siren outage cannot be determined. No damage to plant equipment or structures was identified from the severe weather and all outside work activities has resumed. The NRC Resident Inspector has been notified.
The licensee is retracting this event based on the following: The emergency notification sirens have a battery backup when normal power is lost. Normal power was restored in approximately four hours. It was verified that the three sirens were powered from the battery backup during the time that normal power was unavailable and were always functional. Therefore, this event is not reportable per 10 CFR 50.72. The NRC Resident Inspector has been notified. Notified R4DO (OKeefe).
|ENS 46685||19 March 2011 06:54:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
Following a scheduled plant shutdown for refueling the operators were forced to close the Main Steam Isolation Valves (MSIV's) to limit plant cooldown. While opening MSIV's to restore steam to the secondary, a Reactor Trip and Safety Injection (SI) occurred. The MSIV bypass valves were opened to equalize pressure across the MSIV's. Steam header pressure dipped when the MSIV for 'C' Steam Generator (S/G) was opened. The low steamline pressure bistables are rate sensitive and actuated to cause the SI when steam pressure dipped. Lowest steamline pressure was 1040 psig, the low steam line pressure SI actuates at 615 psig. During the SI the PZR (Pressurizer) PORV's cycled approximately 10 times to limit RCS pressure. When the PORV's opened the 'B' PZR Code Safety Main Control Board (MCB) and plant computer alarm actuated but the actual MCB indication did not change nor does plant response indicate that a PZR Code Safety opened. This appears to be an indication problem related to the PORV's cycling. All equipment functioned as required. The station electric buses are aligned to normal offsite power. Decay heat removal is being discharged to the atmospheric relief valves with no indication of primary to secondary leakage. The licensee notified the NRC Resident Inspector.
1. The expected system actuations that occurred when the plant experienced a Safety Injection (SI) 03/19/11 at 04:04 CDT, previously reported on EN 46685 for 10CFR50.72(b)(2)(iv)(A), is also reportable under 10CFR50.72(b)(3)(iv)(A) for Specified System Actuation.
2. During the recovery of the Safety Injection (SI) actuation that occurred 03/19/11 at 04:04 CDT and previously reported on EN 46685, the Safety Injection Signal was reset which blocked any further automatic actuation. This was directed per the appropriate procedure step. There is no Technical Specifications allowed condition for both trains of ECCS to be inoperable, therefore the unit entered Tech. Spec. 3.0.3 due to the Auto SI feature being blocked. LCO 3.5.2 action C.1. directs immediate entry into LCO 3.0.3. The entry into TS 3.0.3 was made at 0411 CDT and exited at 0639 CDT when the Reactor Trip Breakers were reclosed which re-enabled the automatic SI signal. This is reportable under 10CFR50.72(b)(3)(v)(D) for Accident Mitigation. NRC Resident was notified of the update. Notified R4DO(Cain).
|ENS 46575||28 January 2011 11:07:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop|
On Friday, Jan. 28, 2011, the local phone company will upgrade communications lines on the plant site. Telephone (calls coming in and going outside of the plant site) and internet will be out of service from approximately 1 to 3 p.m. (HPN, ERDS, and SPDS will be out of service during this time).
There will be four phone lines that remain operational during the upgrade: (1.) Emergency notification/verification line in the Control Room, Technical Support Center and Emergency Operation Facility; (2.) Control Room; (3.) Main Security; and (4.) Cell Phone in the Control Room.
Alternate means are available to notify the State of Kansas and the County. Also, alternate means are available to notify the emergency plan organization. This work is anticipated to last no longer than two hours. If there are problems, the phone company will revert to the original configuration at the end of that time period. The NRC Resident Inspector has been notified.
Maintenance was completed and tested by 1348 CST. The licensee notified the NRC Resident Inspector. Notified the R4DO (Miller).
|ENS 46488||17 December 2010 17:38:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||A post-fire safe shutdown (PFSSD) circuit analysis identified the potential for a fire in the Control Room to cause multiple proper polarity hot shorts causing the Pressurizer Power Operated Relief Valves (PORV) to open. This postulated failure would require at least three separate 'smart' hot shorts including 1) a positive external hot short, 2) a negative external hot short, and 3) a short across the control room hand switch to cause each PORV to open. This could result in a loss of coolant accident inside the containment building. This circuit analysis also identified that a fire in the control room could cause the recirculation dampers associated with the 'B' Essential Service Water Pump Room and 'B' Emergency Diesel Generator Room to fail open, closed, or anywhere in between. This could cause the room temperatures to drop below the minimum or rise above maximum design temperatures depending on ambient conditions. Compensatory measures are established for early detection and extinguishment of a fire associated with these circuits in the Control Room. Procedure changes are also being developed for Control Room Evacuation. The licensee notified the NRC Resident Inspector.|
|ENS 46457||6 December 2010 05:42:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||(KKJ01A) 'A' Emergency Diesel Generator (EDG) was removed from service and declared inoperable (on) 11/29/2010 at 0500 (CST) for a scheduled 7 day Technical Specification equipment outage to perform various scheduled maintenance items. Technical Specification 3.8.1 Condition B was entered for one Diesel Generator inoperable, utilizing Action B.4.2.2, 'Restore the Diesel Generator to OPERABLE within 7 days AND 10 days from discovery of failure to meet LCO'. On 12/06/2010, it was discovered during the Operability Run Surveillance, STS KJ-015A, utilized to restore the EDG to service, the Engine Analyzer Data Acquisition (software) indicated the No. 12 cylinder is 'out of balance' and will require a clearance order and maintenance repair. On 12/06/2010 (at) 0350 hrs., it was determined that the work required to restore the EDG to service would cause the Tech Spec 3.8.1 Action B.4.2.2 Completion Time requirement of 7 days to be exceeded, requiring a Plant Shutdown per TS 3.8.1 Condition H, with Action H.1, 'Be in Mode 3 within 6 hours', and Action H.2, 'Be in Mode 5 within 36 hours'. Plant Shutdown to Mode 3 was commenced (on) 12/06/2010 at 0418 (CST). The (NRC) Resident Inspector has been contacted. The licensee indicated that required repairs should be completed within 8 hours and expects restart to occur on 12/06/2010.|
|ENS 46428||18 November 2010 19:30:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||A Post Fire Safe Shutdown (PFSSD) circuit analysis identified that certain fuses installed within Train 'B' Exciter/Voltage Regulator cabinet NE106 are susceptible to failure in the event of postulated fire-induced hot shorts within the control room. Loss of power to this circuit will prevent operation of these functions. The emergency pre-positions and manual voltage adjustment circuits are not credited for PFSSD following a control room fire. However, field flashing is credited following a fire in the control room. Failure of field flashing after a postulated fire will prevent voltage generation on the 'B' diesel generator. This could result in the inability of the 'B' train EDG to supply its associated safety bus during the postulated fire. Compensatory measures are established for early detection and extinguishment of a fire associated with this circuit in the Control Room. Additional compensatory measures are being developed. The licensee is not in any tech. spec LCO's as a result of this condition and has established fire watches as a compensatory measure. The licensee notified the NRC Resident Inspector.|
|ENS 46338||17 October 2010 14:35:00||Wolf Creek||NRC Region 4||Westinghouse PWR 4-Loop||At 0953 CDT, Wolf Creek experienced a reactor trip due to low steam generator level. At the time of the trip the plant was in Mode 1 approximately 16% power following a forced outage. A feedwater isolation signal (FWIS) was generated due to high S/G level (P-14) in 'B' S/G (steam generator). The FWIS resulted in a low S/G level. Although a manual reactor trip was ordered by the duty Shift Manager, the manual trip signal was not inserted before the reactor automatically tripped on low steam generator level. Auxiliary Feed Water systems actuated as expected due to low steam generator levels. The plant is presently in Mode 3 at normal operating temperature and pressure. The Senior Resident Inspector has been notified. All control rods fully inserted during the trip. All three Auxiliary Feedwater Pumps started to maintain S/G levels. The plant was stabilized with the motor driven startup feedwater pump maintaining S/G level. Decay heat is being removed using the atmospheric steam dumps. There is no primary to secondary leakage. The plant is in its normal shutdown electrical lineup. A press release will be issued.|