ML17328A854

LER 90-012-00:on 901212,reactor Tripped as Result of steam-to-feedwater Flow Mismatch & One turbine-driven Main Feedwater Pump Tripped Due to Erroneous Actuation of Thrust Bearing.Bearing Bench calibr.W/910111 Ltr

ML17328A854
Person / Time
Site:	Cook
Issue date:	01/11/1991
From:	BLIND A A, CARTEAUX P F INDIANA MICHIGAN POWER CO. (FORMERLY INDIANA & MICHIG
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-90-012-01, LER-90-12-1, NUDOCS 9101160001
Download: ML17328A854 (7)

Text

ACCELERATED DISTRIBUTION DEMONS REGULATORY XNFORMATION DISTRIBUTION SYSTEM,.(RIDS)

ACCESSION NBR:9101160001 DOC.DATE'1/01/11 NOTARIZED:

NO FACIL:50-316 Do Donald C.Cook Nuclear Power Plant, Unit 2, Indiana&05000316 DOCKET AUTH.NAME AUTHOR AFFILIATION CARTEAUX P.F.Indiana Michigan Power Co.(formerly Indiana&Michigan Ele BLIND,A.A.

Xndiana Michigan Power Co.(formerly Indiana&Michigan Ele RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 90-012-00:on 901212,reactor tripped as result of steam-to-feedwater flow mismatch&one turbine-driven main feedwater pump tripped due to erroneous actuation of thrust bearing.Bearing bench calibr.W/910111 ltr.DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL'IZE: TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.NOTES: RECIPIENT ID CODE/NAME PD3-1 LA COLBURN,T.

INTERNAL: ACNW AEOD/DS P/TPAB NRR/DET/ECMB 9H NRR/DLPQ/LHFB11 NRR/DOEA/OEAB NRR/DST/SELB 8D LB8D1 G F 02 RGN3 FILE 01 EXTERNAL EG&G BRYCE I J~H NRC PDR NSIC MURPHY,G.A COPIES LTTR ENCL 1 1 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 3 3 1 1 1 1 RECIPIENT ID CODE/NAME PD3-1 PD AEOD/DOA AEOD/ROAB/DS P NRR/DET/EMEB 7E NRR/DLPQ/LPEB10 NRR/DREP/PRPB11 NRR/DST/SICB 7E NRR/DST/SRXB 8E RES/DSXR/EIB L ST LOBBY WARD NSIC MAYS,G NUDOCS FULL TXT COPIES LTTR ENCL'1 1 1 2 2 1 1 1 1 2 2 1 1 1 1 1 1 1 1 1 1 1 1 NOTE TO ALL"RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTE!CONTACT THE DOCUMENT CONTROL DESK, RAOil PI-37 (EXT.20079)TO FI.IXIINATE YOUR NAP!E I ROTI DISTRIBUTION LISTS I.OR DOCUXIENTS YOU DON'T NEED!FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 31 ENCL 31 r~Mf (Indiana michigan Paar er Corn pany Cook Nuclear Plan~One Cook Piece Bridgman.MI 49306 616 465 5901 INDMNA MlCHlaaN PONt'R January 11, 1991 United States Nuclear Regulatory Commission Document Control Desk Rockville, Maryland 20852 Operating Licenses DPR-75 Docket No.50-316 Document Control Manager: Xn accordance with the criteria established by 10 CFR 50.73 entitled Licensee Event Re ortin S stem the following report is being submitted:

90-012-00 Sincerely, A.A.Blind Plant Manager AAB:sb Attachment c'P-;PPP g D.H.Williams, Jr.A.B.Davis, Region III M.P.Alexich P.A.Barrett J.E.Borggren R.F.Kroeger B.Walters-Ft.Wayne NRC Resident Inspector T.Colburn-NRC J.G.Keppler M.R.Padgett G.Charnoff, Esq.Dottie Sherman, ANI Library D.Hahn INPO S.J.Brewer/B.P.

Lauzau B.A.Svensson~gO)d')C'/rgb F,i Jgf 83 f9%

NRC FORM 366 (BSD)U.S.NUCLEAR REGULATORY COMMISSION LlCENSEE EVENT REPORT (LER)APPROVED OMS NO.31604104 EXPIRES: CISOIB2 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 60J)HRS.FORWARD COMMENTS REQAROINQ BURDFN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P030).U.S.NUCLEAR REGULATORY COMMISSION.

WASHINGTON.

DC 20666, AND TO THE PAPERWORK REDUCTION PROJECT (31600'IOC).

OFFICE OF MANAQFMENT ANO BUDGET, WASHINGTON.

DC 20603 FACILITY NAME lll D.C, Cook Nuclear Plant-Unit 2 DOCKET NUMBER 121 PA 6 0 5 0 0 0 3 1 6 1 OFO Reactor Protection System Actuation (-aused by a Steam-to-ceedwater Flow Nismatch in Combination with Low Steam Generator Level EVKNT DATE (5)LER NVMSER (6l REPORT DATF.O)OTHER FACILITIKS INVOLVED ISI MONTH DAY YEAR YEAR@~M;.56OUDNTtAL i~n)NVMDDII (SS"6"0 MONTH NVMODR DAY YEAR r*CILITY NAMES DOCXET NUMBER(3)0 5 0 0 0 1 2 1 2 90 90 0 1 2 000 1 9 1 0 5 0 0 0 OPERATINQ MODE (Dl 1 POWER LEvEL 1 0 0 20A02(D)20A00(c)(1)(B 20A054)(1)(5) 20A054)(I)(61)20ACB lc)l1)(Ir I 20A054)Ill(rl 20A05(c)50M(c)(I I 50.35(cll2) 50.734)l2)(II IN.1 3 4 I (1 I I 6 I 50.734)(1)BII) 6073(c)(2)

Vr)50.734)(1)4) 60.73(r I (2)lrD I 50.734)(2)lr)IIIIAI 50.73(cl(2)(rIDI(SI 50.734)l1)(cl THIS REPORT IS SUBMITTFD tVRSUANT TO THE REQUIREMENTS Of 10 CFR ()t ICnrcn onr orms ot tnrtoDo~ti (111 73.7)(6)73.71(c)OTHER ISprcitt In AOtpoct Dcccw rmt In I'rrt, HRC fcnn 36SAJ NAME LICENSEE CONTACT FOR THIS LER (12)F.Carteaux-Safety and Assessment Superintendent TELEPHONE NVMSEII AREA CODE 61 646 5-901 COMPLETE ONK LINE FOR EACH COMtONENT fAILURE DESCRIBED IN THIS REPORT)13)CAUSE SYSTEM COMPONENT MANUFAC.TUNER EPORTABLE TO NPROS F6&4 CAUSK SYSTEM CQMtONENT MANVFAC.TURER Nurg'Pn.~))3)NJPPLEMENTAL REPORT EXPECTED IW EXPECTED SUBMISSION DATE (16)OAY YEAR YKS III yrt.con pirrr EXPECTED SVdltlSSIDH OA tdi NO ABSTRACT IL(mlt to tc()0 lprcrt, I.r., rpptocntrrtrtr Iittrrn pntlr.tooer trprtnrtttrn Imrti (16)On December 12, 1990 at 0318 hours0.00368 days <br />0.0883 hours <br />5.257936e-4 weeks <br />1.20999e-4 months <br />, the Unit 2 reactor tripped as a result of steam-to-feedwater flow mismatch (difference between steam and feed flows on one of two measured channels of each parameter for a steam generator (SG))in coincidence with low SG level (one of two SG narrow range channels for a SG)conditions in the number 4 SG.These conditions arose following a trip of one of the two Turbine Driven Main Feedwater Pumps (TD-MFWP)due to an erroneous actuation of the turbine thrust bearing wear/shaft position detection alarm and trip device.No malfunctions of safety-related systems or components occurred.The turbine thrust bearing wear/shaft position detection device was removed from the MFWP turbine driver and inspected.

This device, and the similar device on the other turbine driver, were bench calibrated and properly set-up on the MFWP turbines at turning gear and no-load operating speeds.NRC Porto 366 (BBD)

I NRC FORM 366A)669)I U.S.NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT ILER)TEXT CONTINUATION APPROY EO OM6 NO.3150010l EXPIR'ESI ll30)92 ESTIMATEO SUROEN PER RFSPONSE TO COMPLY WTH THIS INFORMATION COLLFCTION REOUESTI 50O HRS.FORWARO COMMENTS REGAROING SUROEN ESTIMATE TO THE RECOROS ANO REPORTS MANAGEMENT SRANCH IP630), U.S.NVCLEAR REGULATORY COMMISSION.

WASHINGTON, OC 20555, ANO TO 1)IE PAPERWORK REDUCTION PRO)ECT (3)50410l).

OFFICE OF MANAGF MENT ANO SUOGET,VIASHINGTON,OC20503.

'ACILITY NAME ll)COCKET NVMSER 12)LER NUMSER (6)560USNTIAI)y>.NUMO5 A"i I IIEY'ISION NUMO f 4 PAGE 131 D.C.Cook Nucleat Plant-Unit 2 TEXT N mo>>)of co If>>Ouuod.uw ouoeooff NRC%%dnn 366AY)l)T)Q 6 Q Q Q 3 9 0-0 1 2 00 02"0 Conditions Prior to Occurence Unit 2 in Node 1 at 100 percent of Rated Thermal Power (RTP).Descri tio of Event At approximately 0318 hours0.00368 days <br />0.0883 hours <br />5.257936e-4 weeks <br />1.20999e-4 months <br /> on December 12, 1990 the Unit 2 (U2)West MFWP (EXIS/SJ-P) turbine (EIIS/SJ-TRB) tz'ipped due to a signal from the turbine thrust beaz'ing wear/shaft position detector device (EIIS/JK-38).

The Operators responded to the control room annunciators (EIIS/XB)by starting an additional condensate boostez pump (EIZS/SD-P)(to assist the remaining MFWP), manually increased speed of the remaining MFWP, and began reducing unit power in an attempt to keep the unit on line.However, in the 43 seconds that ensued between the West MFWP turbine trip and reactor trip,, they were not able to offset the loss of one MFWP at the existing unit power level and the mismatch in steam-to-feedwater flow (EXXS/JF-FFS)coincident with low steam generator (EIIS/AB-BLR) level (EIXS/JE-LS)(all in the loop 4 SG)initiated the reactor trip.Opening of the reactor trip breakers (EXXS/JE-BKR), tuzbine trip (EXIS/TA-TRB), control rod insertion, feedwater isolation (EXIS/JB), and automatic starting (EIZS/JB}of the two MDAFPFs (EIIS/BA-P}

and the TDAFP(EIIS/BA-P) occurred as expected.Operating personnel concurrently performed the applicable Emergency Operating Procedures (EOPs')to verify proper automatic protection system responses and assess appropriate recovery actions for the indicated plant conditions.

Cause o the Event The event is believed to have resulted from some combination of the following three factors related to the Hest MFWP tuzbine shaft position device: Improper adjustment of the device during installation and/or later trouble-shooting, leaving the device with much less than the expected margin to'trip, 2~3~Shifting of the device on the turbine as a result of normal vibration despite the hold-down bolts, Foreign material becoming trapped (or wedged)between the shaft thrust bearing face and the sliding shoe (which rides on the face).NRC FonII 366A (569)

NRC FOAM 368A 16491 U.S.NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)TEXT CONTINUATION APPROVEO OM8 NO.3150010i EXPIRES: C130/93 E5TIMATEO SUAOEN PER RESPONSE TO COMPLY WTH THIS INFORMATION COLLECTION REQUEST: 500 HRS.FORWARO COMMENTS AEGAROING SUAOEN ESTIMATE TO THE RECOROS ANO REPORTS MANAGEMENT BRANCH IP430), U.S.NUCLEAR RE'GULATORY COMMISSION.

WASHINGTON.

OC 30555.ANO TO THE PAPERWORK AEOUCTION PROJECT I31500IOCI.

OFI'ICE OF MANAGEMENT ANO SUOGET.WASHINGTON, OC 30503.FACILITY NAME III COCKET NUMSER 131 LER NUMSEA (SI SEQUENTIAL NVMOEA AEVOION NVMOSA PAGE IJ)D.C.Cook Nuclear Plant-Unit 2 TEXT ill cooco cpoco e neurrd.Pco acAotioool NRC Form 355ASI IIT)0 5 0 0 0 3 9 0 0 1 2 0 0 03 OF 0 4 These BBC shaft position devices are supposed to be calibrated as part of their manufacturing process, however the post-trip inspection disclosed that all the adjusting screws had been moved from their initial settings.This may have occurred when the device was initially set-up on 0he turbine during the refueling overhaul, or later during trouble-shooting on the device with the turbine in operation.

The west MFWP had been overhauled during the refueling with the assistance of the equipment vendor.However, it can not be determined from records if the device had been set as required with the MFWP turbine on turning gear and again at no-load operating speed conditions.

Also, eight days after the initial U2 power ascension following the refueling, the shaft position alarm (EIIS/IB-ZA) began intermittently alarming in the control room.The position device was checked locally (at the turbine)and was indicating "0LI deflection.

Other indications of bearing problems, such as excessive temperature or vibration, also did not exist (for both the alarm problem and the later trip).Plant maintenance personnel at that time tried to adjust the device while it was installed on the MFWP (with it's trip function disabled)using vendor information for guidance.At that time the device was left with free travel in the"+" and"-" directions of shaft motion.Folloving the trip, the device was found with it's travel in the"+" direction entirely used up.The investigation of the device indicated no reason vhy it would suddenly shift from a"trip free" to a"hard trip" condition as all adjustment screws vere found tight.The device is bolted to the thrust bearing housing with two hold-down bolts.The post-trip inspection found some foreign material on the sliding shoe.Anal sis of Event This report is being submitted in accordance with 10 CFR 50.73, paragraph (a)(2)(iv}

as a result of the unplanned actuation of the Unit 2 RPS and ESF.The automatic protection functions vere verified to have functioned properly.The event did not involve an unreviewed safety question as defined in 10 CFR 50.59 paragraph (a)(2), and did not adversely impact the health and safety of the public.Corrective Action The shaft position device was removed from the W-MFWP turbine driver and inspected.

This device, and the similar device on the E-MFWP turbine driver, were then bench calibrated and properly set-up on the MFWP turbines at turning gear and no-load operating NAC Form 3SSA IS SSI NRC FORM 366A I609)\U.S.NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER)TEXT CONTINUATION APPROVEOOMS NO.31500)04 EXPIRES: el30192 ESTIMATEO SUROEN PER RESPONSE TO COMPLY WTH THIS INFORMATION CO(.'LECT)ON R'EQUFSTI 500 HRS, FORWARO COMMENTS REGAROING SUROEN ESTIMATE TO THE RECOROS ANO REPORTS MANAGEMENT SRANCH (F030).U.S.NUCLEAR REGULATORY IMMISSION.

WASHINGTON.

OC 20555.ANO TO 1HE PAI'ERWORK REOUC'TION PRO)ECT (3)500)0(I.

OFFICE OF MANAGEMENT ANO SUOGET, WASHINGTON, OC 20503.FACILITY NAME (1)OOCKET NUMSER (2)YEAR LEA NUMSER (Sl SSOVSNTIAL NVMSER REVISION NVMSSR IrAOE (3)D.C.Cook Nuclear Plant-Unit 2 TExT lit more apace re>>purred, u>>eooe'oool AIRc%%drm 366Asl ()7)o s o o o 3 1 6 9 0 0 1 2 00 04 oF 0 speeds.Lock washers were used with the hold-down bolts for the device on the W-MFWP when it was re-installed, following the post-trip calibration, on the H-MFHP.To prevent recurrence no adjustments of these devices will be attempted while mounted on an operating MFWP turbine.A plant procedure, incorporating the appropriate vendor instructions will be developed to assure the calibration and set-up is done properly.Failed Com onent Identification Manufacturer:

Model No: EIIS Code: Plant I.D.No.: 2-138-BSPW (Unit 2, West Main Feed Pump Turbine, OME-84W, Thrust Hear Test Open Limit Switch)Brown-Boveri (BBC)Shaft Position Supervisor, drawing no.HTGD 90-142 EIIS/JK-38 revious Si i ar Events None.NRC Purer 3SSA (669)