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{{Adams
#REDIRECT [[05000482/LER-2015-003]]
| number = ML15194A039
| issue date = 07/01/2015
| title = LER 15-003-00 for Wolf Creek Generating Station, Regarding Manual Reactor Trip Due to High Steam Generator Level Transient at Low Power
| author name = Smith S L
| author affiliation = Wolf Creek Nuclear Operating Corp
| addressee name =
| addressee affiliation = NRC/Document Control Desk, NRC/NRR
| docket = 05000482
| license number = NPF-042
| contact person =
| case reference number = WO 15-0037
| document report number = LER 15-003-00
| document type = Letter, Licensee Event Report (LER)
| page count = 4
}}
 
=Text=
{{#Wiki_filter:SLF CREEK'NUCLEAR OPERATING CORPORATIONStephen L. SmithPlant ManagerJuly 1, 2015WO 15-0037U. S. Nuclear Regulatory CommissionATTN: Document Control DeskWashington, DC 20555
 
==Subject:==
Docket No. 50-482: Licensee Event Report 2015-003-00, "Manual Reactor Trip due toHigh Steam Generator Level Transient at Low Power"Gentlemen:The enclosed Licensee Event Report (LER) 2015-003-00 is being submitted pursuant to 10 CFR50.73(a)(2)(iv)(A) regarding an Engineered Safety Features Actuation and subsequent manual reactortrip at Wolf Creek Generating Station.This letter contains no regulatory commitments. If you have any questions concerning this matter,please contact me at (620) 364-4093, or Mr. Steven R. Koenig at (620) 364-4041.Sincerely,Stephen L. SmithSLS/rltEnclosurecc: M. L. Dapas (NRC), w/eC. F. Lyon (NRC), w/eA. A. Rosebrook (NRC), w/eSenior Resident Inspector (NRC), w/eP.O. Box 411 / Burlington, KS 66839 / Phone: (620) 364-8831An Equal Opportunity Employer M/F/HC/VET NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY OMB: NO. 3160-0104 EXPIRES: 01/31/2017(02-2014) .1-0 bj-dm ESt irdeno per respmae to coril wfih ls r (ary coiledtorl reqest: 80 hou. RPeapteclessro Ilered ar incorporeat into the licarng proess and fed back to indlby. Sent,comierts regdrig brdet esrrete to the FOA Pnvacy and Information CoI&lecho rand-LICENSEE er-5 F53), U.S. "ex~ Rftdatory Ccnrrrssiat, WVbsirt, DC~ 20555-0501, or y inrtend e-nia...... LICENSEE EVENT REPORT (LER) tom nfocoIectsa gog, and to the Desk Officer, Office of Infbomton and Regduato(See Page 2 for required number of Afrs NEOB-102, (31,5-0104), Oftioed lV nand Budgetshirg DC20503. If a rneans Used to irnpose an irfmation Collection does riot cisplay a ofret valid CMEdigits/characters for each block) otred rurber, the NRC nay not coanuCt or spmaa, and a paeso is rot reqired to resmnd to,the inbrntfion Collection1. FACILITY NAME 2. DOCKET NUMBER 3. PAGEWOLF CREEK GENERATING STATION 05000 482 1 OF 34. TITLE Manual Reactor Trip due to High Steam Generator Level Transient at Low Power5. EVENT DATE 6. LER NUMBER 7. REPORT DATE 8. OTHER FACILITIES INVOLVEDMONT DAY YEAR SEQUENTIAL REV MOT DY YOCERUENUMBER NO. MONTH DAY YEAR 0500005 03 2015 2015 003 -00 07 01 2015 FACILITY NAME DOCKET NUMBER050009. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)El 20.2201 (b) E 20.2203(a)(3)(i) []50.73(a)(2)(i)(C) []50.73(a)(2)(vii)El 20.2201(d) D 20.2203(a)(3)(ii) []50.73(a)(2)(ii)(A) [I 50.73(a)(2)(viii)(A)E 20.2203(a)(1) [ 20.2203(a)(4) []50.73(a)(2)(ii)(B) []50.73(a)(2)(viii)(B)[_ 20.2203(a)(2)(i) []50.36(c)(1)(i)(A) []50.73(a)(2)(iii) El 50.73(a)(2)(ix)(A)10. POWER LEVEL E 20.2203(a)(2)(ii) -50.36(c)(1)(ii)(A) 50.73(a)(2)(iv)(A) []50.73(a)(2)(x)El 20.2203(a)(2)(iii) [ 50.36(c)(2) El 50.73(a)(2)(v)(A) []73.71 (a)(4)25 El 20.2203(a)(2)(iv) 50.46(a)(3)(ii) [] 50.73(a)(2)(v)(B) [-] 73.71 (a)(5)E 20.2203(a)(2)(v) [ 50.73(a)(2)(i)(A) [] 50.73(a)(2)(v)(C) E OTHEREl 20.2203(a)(2)(vi) El50.73(a)(2)(i)(B) 50.73(a)(2)(v)(D) Specify in Abstract below or inNRC Form 366A12. LICENSEE CONTACT FOR THIS LERFACILITY NAME TELEPHONE NUMBER (Include Area Code)Steven R. Koenig, Manager Regulatory Affairs 620-364-404113. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORTMANU- REPORTABLE S MANU- REPORTABLECAUSE SYSTEM COMPONENT FACTURER TO EPIX CAUSE FACTURER TO EPIX14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MONTH DAY YEAREl YES (If yes, complete 15. EXPECTED SUBMISSION DATE) NO SUBMISSIONDATEIABSTRACT (Limit to 1400 spaces, ie., approximately 15 single-spaced typewritten lines)On May 3, 2015 at 1021 Central Daylight Time (CDT), Wolf Creek Generating Station (WCGS) was atapproximately 25% power during startup from Refueling Outage 20. The 'C' steam generator receiveda Hi-Hi level signal while the Reactor Operator was manually transferring feedwater control from theMain Feedwater Regulating Valve (MFRV) bypass valves to the MFRVs. This resulted in a main turbinetrip, feedwater isolation, and auxiliary feedwater actuation. A manual reactor trip was initiated at 1022CDT. The root cause was the lack of a reliable and consistent standardization between the operatingcrews to control the transfer of the steam generator feedwater flow between the MFRV bypass valvesand MFRVs and a sense of urgency by the control room operators.The event is bounded by analyses as reported in the Wolf Creek Generating Station (WCGS) UpdatedSafety Analysis Report (USAR) Section 15.2.7, "Loss of Normal Feedwater Flow."NRC FORM 366 (02-2014)
NRCFORM366A U.S.NLUCEARREGULATORY COMMISSION APPROVED BYOMB: NO.3150-0104 EXPIRES: 01/31/2017(02-2014) Estimated burden per response t comply with this mandatory collection request: 80 hoursReported lessons learned are incorporaed hi the licensing process and fed badc to industrySend comments regarding burden estimate to the FOIA, Privacy and Information Collection,Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington ,DC 20555-0001, or bO..LICENSEE EVENT REPORT (LER) internet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer,Office of Inform atio n and Regulatory Affairs, NEOB-10202, (3150-0104), Office of ManagemenCONTINUATION SHEET and Budget, Washington, DC 20503. If a means used to impose an information collection doernot display a currently valid OMB control number, the NRC may not conduct or sponsor, and__erson is not reouired to respond to, the information collection.1 .FACU-YNAIVE 2.DOCKET 6. LER NUMBER 3. PAGEYEAR SEQUENTIAL REVWOLF CREEK GENERATING STATION 05000Y482 NUMBER NO.2015 -003 00NARRATIVEPLANT CONDITIONS PRIOR TO THE EVENTMode -1Power -25%There were no systems, structures or components (SSC) that were inoperable at the start of the event andcontributed to the event.DESCRIPTIONOn May 3, 2015 at 1021 Central Daylight Time (CDT), Wolf Creek Generating Station (WCGS) was atapproximately 25% power during startup from Refueling Outage 20. Feedwater control [EllS: JB] was inthe process of being transferred, from the Main Feedwater Regulating Valve (MFRV) bypass valves [EllS:SJ-V] to the MFRVs. During transfer to the MFRV for the 'C' steam generator (SG) [EIIS: SB-SG], theindicated feedwater flow to the SG increased to a rate higher than expected. Actions were taken to lowerthe MFRV open demand signal, but it was not adequate to turn the rising SG level trend. A feedwaterisolation occurred due to the 'C' SG level >78% and the main turbine tripped. An auxiliary feedwateractuation occurred which started the motor-driven auxiliary feedwater pumps [EllS: BA-P]. The reactorwas manually tripped at 1022 CDT and all safety systems responded as expected.During the transfer between the MFRV bypass valves and MFRVs, both the 'A' and 'C' SG MFRVs wereoperated simultaneously by two Reactor Operators. Both MFRVs were operated with approximately 10-30% valve position movements. The 'A' MFRV transfer occurred in approximately 40 seconds while the'C' MFRV transfer occurred at a similar rate before the plant trip. The 'B' MFRV transfer was beingperformed at the time of the plant trip.It was noted that the operation of the pushbutton for AEFK0530, 'C' MFRV Controller, had a distinctdifference from the other three MFRV controllers. The 'C' controller was replaced as a precaution. Notuning adjustments were performed on the control loop.The plant returned to Mode 1 on May 4, 2015 at 0424 CDT. Feedwater control was successfullytransferred from the MFRV bypass valves to the MFRVs on May 4, 2015 at 1342 CDT.REPORTABILITYThe manual reactor trip and actuation of Engineered Safety Feature Actuation System (ESFAS)instrumentation actuation described in this event is reportable per 10 CFR 50.73(a)(2)(iv)(A), whichrequires reporting of "Any event or condition that resulted in manual or automatic actuation of any of thesystems listed in paragraph (a)(2)(iv)(B) of this section." Paragraph (B)(1) of 10 CFR 50.73(a)(2)(iv)includes "Reactor Protection System (RPS) including: reactor scram or reactor trip." Paragraph (B)(6) of 10CFR 50.73(a)(2)(iv) includes "PWR auxiliary or emergency feedwater."NRC FORM 366A (02-2014)
C FORM 366A LICENSEE EVENT REPORT (LER) U.S. NUCLEAR REGULATORY COMMISSION(02-2014)CONTINUATION SHEET1.FACILITY NAME 2.DOCKET 6. LER NUMBER 3.PAGEYEAR SEQUENTIAL REVWOLF CREEK GENERATING STATION NUMBER NO.05000 482 3 OF 32015 -003 -O00NARRATIVECAUSEThe root cause was the lack of a reliable and consistent standardization between the operating crews tocontrol the transfer of the SG feedwater flow between the MFRV bypass valves and MFRVs.This cause is supported by the sense of urgency by the operators to perform the MFRV transferevolution, which has been reinforced through prior experience, briefings, and training focus. This led tomore than minor adjustments in MFRV controller output, and these tasks being performed simultaneouslyon more than one SG. In addition, the procedure allows operators to develop their own methods forMFRV transfer which varied among the operators making adjustments on SG level simultaneously.CORRECTIVE ACTIONSThe 'C' MFRV Controller, was replaced.Operators were provided training in the current training cycle on what occurred on May 3, 2015 to causethe main turbine trip and subsequent manual reactor trip. A similar malfunction was incorporated into aMFRV controller on the WCGS simulator.During the May 4, 2015 startup, additional actions were implemented to standardize the transfer of theMFRV bypass valves to the MFRVs. An optimized process of SG level control transfer between theMFRV bypass valves and MFRVs was incorporated into procedures.SAFETY SIGNIFICANCEThe safety significance of this event is low. There were no adverse effects on the health and safety of thepublic. This event is analyzed as reported in WCGS Updated Safety Analysis Report (USAR) Section15.2.7, "Loss of Normal Feedwater Flow." Results of the analysis show that a loss of normal feedwaterdoes not adversely affect the core, the reactor coolant system, or the steam system, since the auxiliaryfeedwater capacity is such that reactor coolant water is not relieved from the pressurizer relief or safetyvalves.OPERATING EXPERIENCE/PREVIOUS EVENTSLER 2010-012-00 described a reactor trip at 15% power due to low SG levels. The cause was operationof the plant during power ascension outside the MFRV bypass valves optimum operating region and thefeedwater preheating limitations. Procedures were revised to correct this condition.LER 2011-006-00 described a reactor trip in Mode 4 due to low SG levels. The cause was failure toadequately maintain SG levels using the MFRV bypass valves.NRCFORM366A (02-2014)}}

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