ML15303A004

Part 21 Report Regarding Westinghouse Type KIR-60 Current Transformer, Per Waterford, Unit 3

ML15303A004
Person / Time
Site:	Waterford
Issue date:	10/23/2015
From:	Meiklejohn S Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
51492
Download: ML15303A004 (6)

Text

10/23/2015U.S. Nuclear Reeulatorv Commission Oneratinnx Center Ewnt :I1 / /2 1U.S...N..... ... Re uatr ..... J ........... flpaC" ........ ...... ....... R ynrI 1Power Reactor Event # 51492Site: WATERFORD Notification Date!/Time: 10/23/2015 12:04 (EDT)Unit: 3 Region: 4 State : LA Event Date!/ Time: 10/23/2015 (CDT)Reactor Type: [3] CE Last Modification: 10/23/2015Containment Type: DRY AMBNRC Notified by: SCOTT MEIKLEJOHN Notifications: GREG WERNER R4DOHQ Ops Officer: DANIEL MILLS PART 21/50.55 REACTOREMAILEmergency Class: NON EMERGENCY10 CFR Section:21.21(d)(3)(i) DEFECTS AND NONCOMPLIANCEUnit Scram Code TRXCrit mnit Power Initial RX Mode .Curr Power Current RX Mode3 N {Yes 100 Power Operation 100 Power OperationPART 21 -WESTINGHOUSE TYPE KIR-60 CURRENT TRANSFORMERThe following is excerpted from LER 2015-007 submitted by the licensee:"On October 9, 2015, Waterford 3 received information from the external evaluation concerning the GeneratorDifferential Current Transformer. The evaluation concluded that a manufacturing defect internal to the currenttransformer was the cause of the failure. On October 22, 2015, engineering evaluation determined themanufacturing defect could create a substantial safety hazard, as defined in 10 CFR 21, and provided the site vicepresident information of the defect the same day. Additional information identified in the report is as follows:"Constructor -Westinghouse Type KIR-60 current transformer, style 7524A01 Gi6, serial number 28218571;Defect and safety hazard -There were voids found in the insulation, and the thickness of the insulation materialaround the fault area appeared reduced when compared to the other areas of the current transformer. There isonly one transformer of this type remaining installed in the plant. Scheduled replacement is no later thanNovember 15, 2015."C9 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 31 50-0104 EXPIRES: 0113112017(02-2014)burden per response to comply with this mandatory collection request: 00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />.lessons learned are incorporated into the licensing process and fed back to industry.Send comments regarding burden estimate to the FOIA, Privacy and Information CollectionsEVENT REPORT (LER ) Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or byinternet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Infonmation and(See Page 2 for required number of RegalatoryAffairs, NEOB-10202, (3150-0104), Offce of Management and Badget, Washington, DCdigit/charctersfor each block) 20503. If a means used to impose an information collection does not display a carrentfy valid 0MBdigis/cara~erscontrol number, the NRC may not conduct or sponsor, and a person is not reqaired to respond to,the information collection.1. FACILITY NAME 2. DOCKET NUMBER 1.PGWaterford 3 Steam Electric Station 0008[1O4. TITLEBoth Emergency Diesel Generators Declared Inoperable5. EVENT DATE 6. LER NUMBER I 7. REPORT DATE 8. OTHER FACILITIES INVOLVEDMOT A ER I oREV~iMNH DY YA FACILITY NAME DOCKET050NUMBER0 26 21 205-007 -00i 10 23 2015 FlTNAEDCTUMR050009. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)D] 20.2201(b) [] 20.2203(a)(3)(i) [] 50.73(a)(2)(i)(C) D] 50.73(a)(2)(vii)D] 20.2201(d) [] 20.2203(a)(3)(ti) [] 50.73(a)(2)(-ii)(A) .[ 50.73(a)(2)(viii)(A)D] 20.2203(a)(1) [] 20.2203(a)(4) [] 50.73(a)(2)(ii)(g) [] 50.73(a)(2)(viii)(B)___________ 20.2203(a)(2)(i) [] 50.36(c)(1)(i)(A) [] 50.73(a)(2)(iii) [] 50.73(a)(2)(ix)(A)10. POWER LEVEL. D 20.2203(a)(2)(ii) [] 50.36(c)(1)(ii)(A) [] 50J73(a)(2)(iv)(A) [] 50.73(a)(2)(x)D] 20.2203(a)(2)(iii) [] 50.36(c)(2) [] 50.73(a)(2)(v)(A) LI 73.71(a)(4)LI 20.2203(a)(2)(iv) [] 50.46(a)(3)(ii) [] 50.73(a)(2)(v)(B) LI 73.71(a)(5)100LI 20.2203(a)(2)(v) W] 50.73(a)(2)(i)(A) [] 50.73(a)(2)(v)(C) [] OTHER 10OCFR Part 21[] 2.223(a(2)vi) [] 5.73a)()(i(B) [] 5.73a)()(v(D)Specify in Abstract below or in50.7(a)2)(v(D)NRC Form 366A12. LICENSEE CONTACT FOR THIS LERLICENSEE CONTACT TLPOENME IcueAaCoe13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORTMANU- REOTBEMN- RPRALCAUSE SYSTEM COMPONENT. FACTURERMAU TEOTALo EPIX CAUSE SYSTEM COMPONENT TATRE EOTALo EPIXB EK XCT C634 Y BEKSL A 0Y14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MNH DY YASUBMISSION 02 h 1 21Z] YES (If yes, complete 15. EXPECTED SUBMISSION DATE) LI NO DATE 21ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) !On August 26, 2015, both the 'A' and 'B' Emergency Diesel Generators were declared inoperable~icausing entry intoTechnical Specification 3.8.1.1 action f.On August 26, 2015, Emergency Diesel Generator (EDG) 'A' was declared inoperable following a trip of EDG 'A' onGenerator Differential. Technical Specification (TS) 3.8.1.1 actions b. and d. were entered. Investigation laterdetermined that EDG 'A' tripped on Generator Differential due to a failed Current Transformer. EDG 'B' wassubsequently started per TS 3.8.1.1 action b.(1). EDG 'B' was declared inoperable due to the room exhaust fan notstarting when the diesel engine was started, and TS 3.8.1.1 .f. was entered. Troubleshooting determined that the EDG'B' room exhaust fan did not start due to HVR-501 B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) not opening.Action was taken to isolate air and fail HVR-501 B to its open safety position. EDG 'B' was declared operable and TS3.8.1.1 .f. was exited following verification of proper operation of the EDG 'B' exhaust fan. For the EDG 'A' GeneratorDifferential trip, the Apparent Cause was determined to be manufacturer fabrication that was less t~han adequate topreclude component failure, based on external vendor input. For the EDG 'B' room exhaust fan fa'ilure, the directcause was determined to be that solenoid valve HVR-ISV-501 B failed mechanically, resulting in damper HVR-501 B notopening. An Equipment Apparent Cause Evaluation is being performed and the vendor evaluationl is in progress todetermine the cause of the solenoid valve failure. !NRC FORM 366 (02-201 4)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0113112017(02-2014) Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.:',,.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 CollectionsBranch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by* ,-. LICENSEE EVENT REPORT (LER) internet e-mail to Infocollects.Resoarse@nrc.gov, and to the Desk Officer, Office of Information' and Regulatory Affairn, NEOB-10202, (3150-0104), Office of Management and Budget,CONTINUATION SHEET Washington, DC 20503. If a means ased to impose an information collection does not display acurrently vatid OMB control number, the NRC may not conduct or sponsor, and a person is not' required to respond to, the information collection.1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEI-SEQUENTIAL REVIYEAR NUMBER NO.Waterford 3 Steam Electric Station 05000382 J 2 OF 52015 -007 -00NARRATIVEINITIAL CONDITIONSWaterford 3 was in Mode 1 at approximately 100% power. There were no structures, components, or systems thatwere inoperable at the start of the event that contributed to the event.EVENT DESCRIPTIONOn August 26, 2015, at 0111 CDT, EDG [DG] 'A' was declared inoperable following a trip of EDG 'A' on GeneratorDifferential [87]. TS 3.8.1.1 actions b. and d. were entered. EDG 'A' was being run in accordance with OP-903-1 15,"Train A Integrated Emergency Diesel Generator/Engineering Safety Features Test," Section 7.4, "24 hr EDG 'A'Run with Subsequent Diesel Start" to satisfy TS Surveillance Requirement (SR) 4.8.1.1 .2.e.6. EDG 'B' wassubsequently started per TS 3.8.1.1 action b.(1) which requires the demonstration of Operability of the remainingOperable EDG to preclude common mode failure of the remaining EDG. At 0740 CDT, EDG 'B' was declaredinoperable and TS 3.8.1.1 .f. (restore one of the inoperable EDGs to Operable status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at leastHot Standby within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) was entered due to the EDG 'B' room exhaust fan [FAN] not starting whenthe diesel engine was started. Troubleshooting determined that the EDG 'B' room exhaust fan did not start due toHVR-501 B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) [DMP] not opening. Action was taken to isolate air andfail HVR-501 B to its open safety position. At 1001 CDT, EDG 'B' was declared operable and TS 3.8.1.1 .f. wasexited following verification of proper operation of the EDG 'B' room exhaust fan. The station remained in TS3.8.1.1 .b. and d. with EDG 'A' remaining inoperable.The amount of time that both EDGs were inoperable was 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 20 minutes. During this time, a brief wasconducted and preparations for a plant shutdown were completed. Prior to exceeding the allowed outage time,EDG 'B' damper HVR-501 B was failed open and the room exhaust fan started.EDG 'A' Generator DifferentialEDG 'A' was being run in accordance with OP-903-1 15, "Train A Integrated Emergency DieselGenerator/Engineering Safety Features Test," Section 7.4, "24 hr EDG 'A' Run with Subsequent Diesel Start" tosatisfy TS SR 4.8.1.1 .2.e.6. The EDG function of supplying standby electrical power on receipt of a "test" or"emergency" command signal are different in that during an Emergency Mode start of the EDG, all Test Mode tripsand alarms are bypassed with the exception of overspeed and generator differential.The direct cause for EDG 'A' tripping on GENERATOR DIFFERENTIAL was the internal shorting of EG ECT231 6 CTRANSF, NB8 Current Transformer, due to insulation failure.The EG ECT2316 C TRANSF is a Westinghouse type KIR-60 current transformer style 7524A01G16 with serialnumber 28218571. There are no lot or date codes printed on the current transformer or its nameplate. The currenttransformer is only energized when EDG 'A' is supplying the 3A bus.A vendor performed a failure analysis of the failed EG ECT23I16 C TRANSF, current transformer and issued afailure analysis report dated October 9, 2015. The report concluded that the failure was due to a manufacturingdefect. Specifically, there were voids found in the insulation and the thickness of the insulation material around thefault area appeared reduced when compared to the other areas of the current transformer. It is believed that thethinner insulation in combination with voids increased the electrical stresses causing the insulation to break down.This eventually resulted in a fault. The insulation breakdown and resultant fault created a ground condition on theDiesel Generator bus.I-UKM (UZ-ZU'I4J NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(02-2014) LICENSEE EVENT REPORT (LER)CONTINUATION SHEET1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEI ER SEQUENTIAL REVYER UMBER NO.Waterford 3 Steam Electric Station 05000382 I 3 OF 51 _____ 2015 -007 -00jNARRATIVEInvestigation to determine if any other current transformers of this make and model were installed in the plantidentified that the EDG 'B' Generator Differential Current Transformer was the same. Additionally, there are powercurrent "donut style" transformers for EDG 'A' and EDG 'B', nine per EDG, feeding the regulator circuit. These are adifferent manufacturer, model, and construction, but are bus type current transformers that are the same age and inthe same cabinet environment as the EG ECT231 6 C TRANSF, NB8 Current Transformer.EDG 'B' HVR 501 B failureOn August 26, 201.5, EDG 'B' was started per TS 3.8.1.1 action b.(1 ) which requires the demonstration ofOperability of the remaining Operable EDG to preclude common mode failure of the remaining EDG. At 0740 CDT,EDG 'B' was declared inoperable and TS 3.8.1.1 .f. (restore one of the inoperable EDG's to Opberable status within 2hours or be in at least Hot Standby within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) was entered due to the room exhaust fan notstarting when the diesel engine was started. Troubleshooting determined that the EDG 'B' fan did notstart due to HVR-501 B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) not opening. The solendid on HVR-501 Bwas replaced and tested satisfactorily. The solenoid was inspected on site both externally and internally and it wasdetermined that there was mechanical wear on the inside of the solenoid, the air inlet valve plug bound upinside the solenoid coil, and that the solenoid coil itself appeared to be good. Photographs of the :condition weresent to an offsite vendor who concluded that rapid cycling of the solenoid valve might be the cause of the excessivewear and damage to the components. The design of the exhaust fan inlet damper for EDG 'A' (HVR-501A) (EG A ROOM OUTSIDE AIR! INTAKEDAMPER) is different than for EDG 'B'. HVR-501A is located on the side wall of the EDG 'A' Room and HVR-501 Bis located in the overhead outside of EDG 'B' Room. These inlet dampers will open whenever the associated fanstarts whether in manual or in the event of an emergency start. HVR-501A is a large wall-mounted damper that isdivided into four sections. HVR-501 B is a single damper installed in its associated ductwork. There are four inletdamper sections that make up HVR-501A. Each damper set has its own air actuator and an air supply solenoidvalve. The failure of a single solenoid valve will not prevent the starting of the EDG 'A' Exhaust F~an.An equipment apparent cause evaluation and an additional investigation is ongoing to cause of thefailure of HVR-501 B from opening.REPORTABLE OCCURRENCE.TS 3.8.1.1 requires that two separate and independent diesel generators shall be operable, each' with diesel oil feedtanks containing a minimum volume of 339 gallons of fuel, a separate diesel generator fuel oil storage tank, and aseparate fuel transfer pump. TS 3.8.1.1 Action b: With one diesel generator of 3.8.1.1 .b. inoperable: (1) Demonstrate the OPERABILITY of theremaining A.C. circuits by performing SR 4.8.1.1.1 .a. (separately for each offsite A.C. circuit) within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and atleast once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. If the diesel generator became inoperable due to any cause other than aninoperable support system, an independently testable component, or preplanned maintenance or testing,demonstrate the OPERABILITY of the remaining OPERABLE diesel generator (unless it has been successfullytested in the last 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) by performing SR 4.8.1.1 .2.a.4. within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> unless the absence of any potentialcommon mode failure for the remaining diesel generator is demonstrated. !I.TS 3.8.1.1 Action f: With two of the above required diesel generators inoperable, demonstrate the OPERABILITY oftwo offsite AC circuits by performing SR 4.8.1.1 .a. within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter; restoreone of the inopera~ble diesel generators to OPERABLE status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least Hot:Standby within thenext 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Following restoration of one diesel generatorfollow Action statement b. with the time requirement of that action statement based on the time of initial loss of theremaining inoperable diesel generator. INRC FORM 366A (02-2014)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(02-2014) LICENSEE EVENT REPORT (LER)CONTINUATION SHEET1. FACILITY NAME 2. DOCKET 6. LER NUMBER j 3. PAGEYEA SEQUENTIAL REVI 5038 ER NUMBER NO.Waterford 3 steam Electric Station 45038IOF 52015 -007 -00NARRATIVEThis event is reportable under 10 CFR 50173 (a)(2)(v)(A) and 10 CFR 50.73 (a)(2)(v)(D) "Any event or condition thatcould have prevented the fulfillment of the safety function of structures or systems that are needed to: (A) Shutdown the reactor and maintain it in a safe shutdown condition, and (0) Mitigate the consequences of an accident."10 CFR 21 IDENTIFICATIONOn October 9, 2015, Waterford 3 received information from the external evaluation concerning the GeneratorDifferential Current Transformer. The evaluation concluded that a manufacturing defect internal to the currenttransformer was the cause of the failure. On October 22, 2015, engineering evaluation determined themanufacturing defect could create a substantial safety hazard, as defined in 10 CFR 21, and provided the site vicepresident information ef the defect the same day. Additional information identified in the report is as follows:Constructor -Westinghouse Type KIR-60 current transformer, style 7524A01G16, serial number 28218571; Defectand safety hazard -There were voids found in the insulation, and the thickness of the insulation material around thefault area appeared reduced when compared tothe other areas of the current transformer. There is only onetransformer of this type remaining installed in the plant. Scheduled replacement is no later than November 15, 2015.SYSTEM DESCRIPTIONThe purpose of the EDGs is to provide an emergency source of AC power to safety buses [EB] 3A and 3B during aloss of the preferred (offsite) and standby (onsite) AC power supplies to permit the ESF systems to perform theirsafety functions.There are two "operating'i modes of the EDGs -TEST mode and EMERGENCY mode. Any manual diesel startsignal places the diesel in TEST mode. TEST mode is used for post-maintenance testing or routine surveillance. InTEST mode, the engine employs a large number of shutdown features which protect the engine for use duringemergency situations. Any automatic diesel start places the diesel in EMERGENCY mode. In this mode, most ofthe TEST mode protective trips are bypassed to ensure the diesel runs continuously and reliably. Automatic startsignals include safety injection actuation, safety bus undervoltage, and safety bus degraded voltage.The purpose of the EDG Ventilation System is to remove the heat associated with diesel operation from the EDG 'A'and 'B' Rooms. During normal plant operations, the Reactor Auxiliary Building (RAB) Normal Ventilation SystemIVF] maintains temperature in the EDG rooms between 50°F and 120°F, while the EDG Ventilation System remainsin standby and starts in conjunction with a diesel start. The RAB Normal Ventilation System is not required tooperate following a design basis accident. The EDG Ventilation System is designed to maintain the temperature inthe diesel generator rooms at a minimum of 50°F and a maximum of 1 20°F whenever the EDGs are in operation.APPARENT CAUSEThe apparent cause of the EDG 'A' trip on generator differential is manufacturer fabrication that is less thanadequate to preclude component failure. This apparent cause resulted in the condition where thinner insulation inthe current transformer in combination with voids created during the manufacturing process increased the electricalstresses, thereby causing the insulation to break down. This condition eventually resulted in a fault. The insulationbreakdown and resulting fault created a ground condition on the Diesel Generator bus which tripped EGEGEN0001-A, EDG 'A' on GENERATOR DIFFERENTIAL.NFRC FORM 366A (02-2014)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(02-2014) LICENSEE EVENT REPORT (LER)CONTINUATION SHEET1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEIISEQUENTIAL REVYER UMBER NO.Waterford 3 Steam Electric Station 05000382 YER5 OF 5I _____j2015 -007 -00.NARRATIVECORRECTIVE ACTIONSFor Failed Current Transformer on EDG 'A':Completed Actions1. Replace Current Transformer in EDG 'A'2. Failure analysis on the failed EDG 'A' Current TransformerActions1. Replace remaining "donut style" transformers on EDG 'A' and 'B' (nine per EDG)2. Replace Current Transformer for Generator Differential on EDG 'B'3. Create a preventive maintenance task to replace the EG ECT2316 C TRANSF, NB8 Current Transformer4. Create a preventive maintenance task to replace power current "donut style" transformers for EDG 'A' and EDG'B'For EDG 'B':Completed Actions1. Replace Solenoid [SOL] associated with HVR-501 BBased on the initial evaluation, an Equipment Apparent Cause Evaluation is being performed to determine thecause of the rapid cycling of the solenoid. Once this evaluation is completed, and depending on the determinationof the testing, the root cause will be revised. This LER will be revised to include the Root Cause and ContributingCauses.SAFETY SIGNIFICANCEIndustrial Safety: There was no industrial safety significance associated with this issue.Radiological Safety: There was no radiological safety significance associated with this issue.Environmental Safety: There was no environmental safety significance associated with this issue.Nuclear Safety: The equipment apparent cause evaluation is still in progress and has not been approved by sitemanagement. The safety significance determination is not yet completed. Nuclear safety significance will beincluded as a planned update to this LER.ADDITIONAL INFORMATIONEnergy industry identification system (EllS) codes and component function identifiers are identified in the text withbrackets [ ].NRC FORM 366A (02-2014) 10/23/2015U.S. Nuclear Reeulatorv Commission Oneratinnx Center Ewnt :I1 / /2 1U.S...N..... ... Re uatr ..... J ........... flpaC" ........ ...... ....... R ynrI 1Power Reactor Event # 51492Site: WATERFORD Notification Date!/Time: 10/23/2015 12:04 (EDT)Unit: 3 Region: 4 State : LA Event Date!/ Time: 10/23/2015 (CDT)Reactor Type: [3] CE Last Modification: 10/23/2015Containment Type: DRY AMBNRC Notified by: SCOTT MEIKLEJOHN Notifications: GREG WERNER R4DOHQ Ops Officer: DANIEL MILLS PART 21/50.55 REACTOREMAILEmergency Class: NON EMERGENCY10 CFR Section:21.21(d)(3)(i) DEFECTS AND NONCOMPLIANCEUnit Scram Code TRXCrit mnit Power Initial RX Mode .Curr Power Current RX Mode3 N {Yes 100 Power Operation 100 Power OperationPART 21 -WESTINGHOUSE TYPE KIR-60 CURRENT TRANSFORMERThe following is excerpted from LER 2015-007 submitted by the licensee:"On October 9, 2015, Waterford 3 received information from the external evaluation concerning the GeneratorDifferential Current Transformer. The evaluation concluded that a manufacturing defect internal to the currenttransformer was the cause of the failure. On October 22, 2015, engineering evaluation determined themanufacturing defect could create a substantial safety hazard, as defined in 10 CFR 21, and provided the site vicepresident information of the defect the same day. Additional information identified in the report is as follows:"Constructor -Westinghouse Type KIR-60 current transformer, style 7524A01 Gi6, serial number 28218571;Defect and safety hazard -There were voids found in the insulation, and the thickness of the insulation materialaround the fault area appeared reduced when compared to the other areas of the current transformer. There isonly one transformer of this type remaining installed in the plant. Scheduled replacement is no later thanNovember 15, 2015."C9 NRC FORM 366 U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 31 50-0104 EXPIRES: 0113112017(02-2014)burden per response to comply with this mandatory collection request: 00 hours0 days <br />0 hours <br />0 weeks <br />0 months <br />.lessons learned are incorporated into the licensing process and fed back to industry.Send comments regarding burden estimate to the FOIA, Privacy and Information CollectionsEVENT REPORT (LER ) Branch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or byinternet e-mail to Infocollects.Resource@nrc.gov, and to the Desk Officer, Office of Infonmation and(See Page 2 for required number of RegalatoryAffairs, NEOB-10202, (3150-0104), Offce of Management and Badget, Washington, DCdigit/charctersfor each block) 20503. If a means used to impose an information collection does not display a carrentfy valid 0MBdigis/cara~erscontrol number, the NRC may not conduct or sponsor, and a person is not reqaired to respond to,the information collection.1. FACILITY NAME 2. DOCKET NUMBER 1.PGWaterford 3 Steam Electric Station 0008[1O4. TITLEBoth Emergency Diesel Generators Declared Inoperable5. EVENT DATE 6. LER NUMBER I 7. REPORT DATE 8. OTHER FACILITIES INVOLVEDMOT A ER I oREV~iMNH DY YA FACILITY NAME DOCKET050NUMBER0 26 21 205-007 -00i 10 23 2015 FlTNAEDCTUMR050009. OPERATING MODE 11. THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR §: (Check all that apply)D] 20.2201(b) [] 20.2203(a)(3)(i) [] 50.73(a)(2)(i)(C) D] 50.73(a)(2)(vii)D] 20.2201(d) [] 20.2203(a)(3)(ti) [] 50.73(a)(2)(-ii)(A) .[ 50.73(a)(2)(viii)(A)D] 20.2203(a)(1) [] 20.2203(a)(4) [] 50.73(a)(2)(ii)(g) [] 50.73(a)(2)(viii)(B)___________ 20.2203(a)(2)(i) [] 50.36(c)(1)(i)(A) [] 50.73(a)(2)(iii) [] 50.73(a)(2)(ix)(A)10. POWER LEVEL. D 20.2203(a)(2)(ii) [] 50.36(c)(1)(ii)(A) [] 50J73(a)(2)(iv)(A) [] 50.73(a)(2)(x)D] 20.2203(a)(2)(iii) [] 50.36(c)(2) [] 50.73(a)(2)(v)(A) LI 73.71(a)(4)LI 20.2203(a)(2)(iv) [] 50.46(a)(3)(ii) [] 50.73(a)(2)(v)(B) LI 73.71(a)(5)100LI 20.2203(a)(2)(v) W] 50.73(a)(2)(i)(A) [] 50.73(a)(2)(v)(C) [] OTHER 10OCFR Part 21[] 2.223(a(2)vi) [] 5.73a)()(i(B) [] 5.73a)()(v(D)Specify in Abstract below or in50.7(a)2)(v(D)NRC Form 366A12. LICENSEE CONTACT FOR THIS LERLICENSEE CONTACT TLPOENME IcueAaCoe13. COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORTMANU- REOTBEMN- RPRALCAUSE SYSTEM COMPONENT. FACTURERMAU TEOTALo EPIX CAUSE SYSTEM COMPONENT TATRE EOTALo EPIXB EK XCT C634 Y BEKSL A 0Y14. SUPPLEMENTAL REPORT EXPECTED 15. EXPECTED MNH DY YASUBMISSION 02 h 1 21Z] YES (If yes, complete 15. EXPECTED SUBMISSION DATE) LI NO DATE 21ABSTRACT (Limit to 1400 spaces, i.e., approximately 15 single-spaced typewritten lines) !On August 26, 2015, both the 'A' and 'B' Emergency Diesel Generators were declared inoperable~icausing entry intoTechnical Specification 3.8.1.1 action f.On August 26, 2015, Emergency Diesel Generator (EDG) 'A' was declared inoperable following a trip of EDG 'A' onGenerator Differential. Technical Specification (TS) 3.8.1.1 actions b. and d. were entered. Investigation laterdetermined that EDG 'A' tripped on Generator Differential due to a failed Current Transformer. EDG 'B' wassubsequently started per TS 3.8.1.1 action b.(1). EDG 'B' was declared inoperable due to the room exhaust fan notstarting when the diesel engine was started, and TS 3.8.1.1 .f. was entered. Troubleshooting determined that the EDG'B' room exhaust fan did not start due to HVR-501 B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) not opening.Action was taken to isolate air and fail HVR-501 B to its open safety position. EDG 'B' was declared operable and TS3.8.1.1 .f. was exited following verification of proper operation of the EDG 'B' exhaust fan. For the EDG 'A' GeneratorDifferential trip, the Apparent Cause was determined to be manufacturer fabrication that was less t~han adequate topreclude component failure, based on external vendor input. For the EDG 'B' room exhaust fan fa'ilure, the directcause was determined to be that solenoid valve HVR-ISV-501 B failed mechanically, resulting in damper HVR-501 B notopening. An Equipment Apparent Cause Evaluation is being performed and the vendor evaluationl is in progress todetermine the cause of the solenoid valve failure. !NRC FORM 366 (02-201 4)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED BY 0MB: NO. 3150-0104 EXPIRES: 0113112017(02-2014) Estimated burden per response to comply with this mandatory collection request: 80 hours9.259259e-4 days <br />0.0222 hours <br />1.322751e-4 weeks <br />3.044e-5 months <br />.:',,.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 CollectionsBranch (T-5 F53), U.S. Nuclear Regulatory Commission, Washington, DC 20555-0001, or by* ,-. LICENSEE EVENT REPORT (LER) internet e-mail to Infocollects.Resoarse@nrc.gov, and to the Desk Officer, Office of Information' and Regulatory Affairn, NEOB-10202, (3150-0104), Office of Management and Budget,CONTINUATION SHEET Washington, DC 20503. If a means ased to impose an information collection does not display acurrently vatid OMB control number, the NRC may not conduct or sponsor, and a person is not' required to respond to, the information collection.1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEI-SEQUENTIAL REVIYEAR NUMBER NO.Waterford 3 Steam Electric Station 05000382 J 2 OF 52015 -007 -00NARRATIVEINITIAL CONDITIONSWaterford 3 was in Mode 1 at approximately 100% power. There were no structures, components, or systems thatwere inoperable at the start of the event that contributed to the event.EVENT DESCRIPTIONOn August 26, 2015, at 0111 CDT, EDG [DG] 'A' was declared inoperable following a trip of EDG 'A' on GeneratorDifferential [87]. TS 3.8.1.1 actions b. and d. were entered. EDG 'A' was being run in accordance with OP-903-1 15,"Train A Integrated Emergency Diesel Generator/Engineering Safety Features Test," Section 7.4, "24 hr EDG 'A'Run with Subsequent Diesel Start" to satisfy TS Surveillance Requirement (SR) 4.8.1.1 .2.e.6. EDG 'B' wassubsequently started per TS 3.8.1.1 action b.(1) which requires the demonstration of Operability of the remainingOperable EDG to preclude common mode failure of the remaining EDG. At 0740 CDT, EDG 'B' was declaredinoperable and TS 3.8.1.1 .f. (restore one of the inoperable EDGs to Operable status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at leastHot Standby within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) was entered due to the EDG 'B' room exhaust fan [FAN] not starting whenthe diesel engine was started. Troubleshooting determined that the EDG 'B' room exhaust fan did not start due toHVR-501 B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) [DMP] not opening. Action was taken to isolate air andfail HVR-501 B to its open safety position. At 1001 CDT, EDG 'B' was declared operable and TS 3.8.1.1 .f. wasexited following verification of proper operation of the EDG 'B' room exhaust fan. The station remained in TS3.8.1.1 .b. and d. with EDG 'A' remaining inoperable.The amount of time that both EDGs were inoperable was 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and 20 minutes. During this time, a brief wasconducted and preparations for a plant shutdown were completed. Prior to exceeding the allowed outage time,EDG 'B' damper HVR-501 B was failed open and the room exhaust fan started.EDG 'A' Generator DifferentialEDG 'A' was being run in accordance with OP-903-1 15, "Train A Integrated Emergency DieselGenerator/Engineering Safety Features Test," Section 7.4, "24 hr EDG 'A' Run with Subsequent Diesel Start" tosatisfy TS SR 4.8.1.1 .2.e.6. The EDG function of supplying standby electrical power on receipt of a "test" or"emergency" command signal are different in that during an Emergency Mode start of the EDG, all Test Mode tripsand alarms are bypassed with the exception of overspeed and generator differential.The direct cause for EDG 'A' tripping on GENERATOR DIFFERENTIAL was the internal shorting of EG ECT231 6 CTRANSF, NB8 Current Transformer, due to insulation failure.The EG ECT2316 C TRANSF is a Westinghouse type KIR-60 current transformer style 7524A01G16 with serialnumber 28218571. There are no lot or date codes printed on the current transformer or its nameplate. The currenttransformer is only energized when EDG 'A' is supplying the 3A bus.A vendor performed a failure analysis of the failed EG ECT23I16 C TRANSF, current transformer and issued afailure analysis report dated October 9, 2015. The report concluded that the failure was due to a manufacturingdefect. Specifically, there were voids found in the insulation and the thickness of the insulation material around thefault area appeared reduced when compared to the other areas of the current transformer. It is believed that thethinner insulation in combination with voids increased the electrical stresses causing the insulation to break down.This eventually resulted in a fault. The insulation breakdown and resultant fault created a ground condition on theDiesel Generator bus.I-UKM (UZ-ZU'I4J NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(02-2014) LICENSEE EVENT REPORT (LER)CONTINUATION SHEET1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEI ER SEQUENTIAL REVYER UMBER NO.Waterford 3 Steam Electric Station 05000382 I 3 OF 51 _____ 2015 -007 -00jNARRATIVEInvestigation to determine if any other current transformers of this make and model were installed in the plantidentified that the EDG 'B' Generator Differential Current Transformer was the same. Additionally, there are powercurrent "donut style" transformers for EDG 'A' and EDG 'B', nine per EDG, feeding the regulator circuit. These are adifferent manufacturer, model, and construction, but are bus type current transformers that are the same age and inthe same cabinet environment as the EG ECT231 6 C TRANSF, NB8 Current Transformer.EDG 'B' HVR 501 B failureOn August 26, 201.5, EDG 'B' was started per TS 3.8.1.1 action b.(1 ) which requires the demonstration ofOperability of the remaining Operable EDG to preclude common mode failure of the remaining EDG. At 0740 CDT,EDG 'B' was declared inoperable and TS 3.8.1.1 .f. (restore one of the inoperable EDG's to Opberable status within 2hours or be in at least Hot Standby within the following 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br />) was entered due to the room exhaust fan notstarting when the diesel engine was started. Troubleshooting determined that the EDG 'B' fan did notstart due to HVR-501 B (EG B ROOM OUTSIDE AIR INTAKE DAMPER) not opening. The solendid on HVR-501 Bwas replaced and tested satisfactorily. The solenoid was inspected on site both externally and internally and it wasdetermined that there was mechanical wear on the inside of the solenoid, the air inlet valve plug bound upinside the solenoid coil, and that the solenoid coil itself appeared to be good. Photographs of the :condition weresent to an offsite vendor who concluded that rapid cycling of the solenoid valve might be the cause of the excessivewear and damage to the components. The design of the exhaust fan inlet damper for EDG 'A' (HVR-501A) (EG A ROOM OUTSIDE AIR! INTAKEDAMPER) is different than for EDG 'B'. HVR-501A is located on the side wall of the EDG 'A' Room and HVR-501 Bis located in the overhead outside of EDG 'B' Room. These inlet dampers will open whenever the associated fanstarts whether in manual or in the event of an emergency start. HVR-501A is a large wall-mounted damper that isdivided into four sections. HVR-501 B is a single damper installed in its associated ductwork. There are four inletdamper sections that make up HVR-501A. Each damper set has its own air actuator and an air supply solenoidvalve. The failure of a single solenoid valve will not prevent the starting of the EDG 'A' Exhaust F~an.An equipment apparent cause evaluation and an additional investigation is ongoing to cause of thefailure of HVR-501 B from opening.REPORTABLE OCCURRENCE.TS 3.8.1.1 requires that two separate and independent diesel generators shall be operable, each' with diesel oil feedtanks containing a minimum volume of 339 gallons of fuel, a separate diesel generator fuel oil storage tank, and aseparate fuel transfer pump. TS 3.8.1.1 Action b: With one diesel generator of 3.8.1.1 .b. inoperable: (1) Demonstrate the OPERABILITY of theremaining A.C. circuits by performing SR 4.8.1.1.1 .a. (separately for each offsite A.C. circuit) within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and atleast once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter. If the diesel generator became inoperable due to any cause other than aninoperable support system, an independently testable component, or preplanned maintenance or testing,demonstrate the OPERABILITY of the remaining OPERABLE diesel generator (unless it has been successfullytested in the last 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />) by performing SR 4.8.1.1 .2.a.4. within 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> unless the absence of any potentialcommon mode failure for the remaining diesel generator is demonstrated. !I.TS 3.8.1.1 Action f: With two of the above required diesel generators inoperable, demonstrate the OPERABILITY oftwo offsite AC circuits by performing SR 4.8.1.1 .a. within 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> and at least once per 8 hours9.259259e-5 days <br />0.00222 hours <br />1.322751e-5 weeks <br />3.044e-6 months <br /> thereafter; restoreone of the inopera~ble diesel generators to OPERABLE status within 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> or be in at least Hot:Standby within thenext 6 hours6.944444e-5 days <br />0.00167 hours <br />9.920635e-6 weeks <br />2.283e-6 months <br /> and in Cold Shutdown within the following 30 hours3.472222e-4 days <br />0.00833 hours <br />4.960317e-5 weeks <br />1.1415e-5 months <br />. Following restoration of one diesel generatorfollow Action statement b. with the time requirement of that action statement based on the time of initial loss of theremaining inoperable diesel generator. INRC FORM 366A (02-2014)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(02-2014) LICENSEE EVENT REPORT (LER)CONTINUATION SHEET1. FACILITY NAME 2. DOCKET 6. LER NUMBER j 3. PAGEYEA SEQUENTIAL REVI 5038 ER NUMBER NO.Waterford 3 steam Electric Station 45038IOF 52015 -007 -00NARRATIVEThis event is reportable under 10 CFR 50173 (a)(2)(v)(A) and 10 CFR 50.73 (a)(2)(v)(D) "Any event or condition thatcould have prevented the fulfillment of the safety function of structures or systems that are needed to: (A) Shutdown the reactor and maintain it in a safe shutdown condition, and (0) Mitigate the consequences of an accident."10 CFR 21 IDENTIFICATIONOn October 9, 2015, Waterford 3 received information from the external evaluation concerning the GeneratorDifferential Current Transformer. The evaluation concluded that a manufacturing defect internal to the currenttransformer was the cause of the failure. On October 22, 2015, engineering evaluation determined themanufacturing defect could create a substantial safety hazard, as defined in 10 CFR 21, and provided the site vicepresident information ef the defect the same day. Additional information identified in the report is as follows:Constructor -Westinghouse Type KIR-60 current transformer, style 7524A01G16, serial number 28218571; Defectand safety hazard -There were voids found in the insulation, and the thickness of the insulation material around thefault area appeared reduced when compared tothe other areas of the current transformer. There is only onetransformer of this type remaining installed in the plant. Scheduled replacement is no later than November 15, 2015.SYSTEM DESCRIPTIONThe purpose of the EDGs is to provide an emergency source of AC power to safety buses [EB] 3A and 3B during aloss of the preferred (offsite) and standby (onsite) AC power supplies to permit the ESF systems to perform theirsafety functions.There are two "operating'i modes of the EDGs -TEST mode and EMERGENCY mode. Any manual diesel startsignal places the diesel in TEST mode. TEST mode is used for post-maintenance testing or routine surveillance. InTEST mode, the engine employs a large number of shutdown features which protect the engine for use duringemergency situations. Any automatic diesel start places the diesel in EMERGENCY mode. In this mode, most ofthe TEST mode protective trips are bypassed to ensure the diesel runs continuously and reliably. Automatic startsignals include safety injection actuation, safety bus undervoltage, and safety bus degraded voltage.The purpose of the EDG Ventilation System is to remove the heat associated with diesel operation from the EDG 'A'and 'B' Rooms. During normal plant operations, the Reactor Auxiliary Building (RAB) Normal Ventilation SystemIVF] maintains temperature in the EDG rooms between 50°F and 120°F, while the EDG Ventilation System remainsin standby and starts in conjunction with a diesel start. The RAB Normal Ventilation System is not required tooperate following a design basis accident. The EDG Ventilation System is designed to maintain the temperature inthe diesel generator rooms at a minimum of 50°F and a maximum of 1 20°F whenever the EDGs are in operation.APPARENT CAUSEThe apparent cause of the EDG 'A' trip on generator differential is manufacturer fabrication that is less thanadequate to preclude component failure. This apparent cause resulted in the condition where thinner insulation inthe current transformer in combination with voids created during the manufacturing process increased the electricalstresses, thereby causing the insulation to break down. This condition eventually resulted in a fault. The insulationbreakdown and resulting fault created a ground condition on the Diesel Generator bus which tripped EGEGEN0001-A, EDG 'A' on GENERATOR DIFFERENTIAL.NFRC FORM 366A (02-2014)

NRC FORM 366A U.S. NUCLEAR REGULATORY COMMISSION(02-2014) LICENSEE EVENT REPORT (LER)CONTINUATION SHEET1. FACILITY NAME 2. DOCKET 6. LER NUMBER 3. PAGEIISEQUENTIAL REVYER UMBER NO.Waterford 3 Steam Electric Station 05000382 YER5 OF 5I _____j2015 -007 -00.NARRATIVECORRECTIVE ACTIONSFor Failed Current Transformer on EDG 'A':Completed Actions1. Replace Current Transformer in EDG 'A'2. Failure analysis on the failed EDG 'A' Current TransformerActions1. Replace remaining "donut style" transformers on EDG 'A' and 'B' (nine per EDG)2. Replace Current Transformer for Generator Differential on EDG 'B'3. Create a preventive maintenance task to replace the EG ECT2316 C TRANSF, NB8 Current Transformer4. Create a preventive maintenance task to replace power current "donut style" transformers for EDG 'A' and EDG'B'For EDG 'B':Completed Actions1. Replace Solenoid [SOL] associated with HVR-501 BBased on the initial evaluation, an Equipment Apparent Cause Evaluation is being performed to determine thecause of the rapid cycling of the solenoid. Once this evaluation is completed, and depending on the determinationof the testing, the root cause will be revised. This LER will be revised to include the Root Cause and ContributingCauses.SAFETY SIGNIFICANCEIndustrial Safety: There was no industrial safety significance associated with this issue.Radiological Safety: There was no radiological safety significance associated with this issue.Environmental Safety: There was no environmental safety significance associated with this issue.Nuclear Safety: The equipment apparent cause evaluation is still in progress and has not been approved by sitemanagement. The safety significance determination is not yet completed. Nuclear safety significance will beincluded as a planned update to this LER.ADDITIONAL INFORMATIONEnergy industry identification system (EllS) codes and component function identifiers are identified in the text withbrackets [ ].NRC FORM 366A (02-2014)