ML18004B912

LER 87-046-00:on 870722,main Feedwater Pump B Tripped Due to Low Flow Resulting in Automatic Start of Auxiliary Feedwater Pumps.Caused by Loose Linkage on Recirculation Valve Due to Vibration.Valve Repaired.Procedures changed.W/870820 Ltr

ML18004B912
Person / Time
Site:	Harris
Issue date:	08/20/1987
From:	Schwabenbauer, Watson R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
HO-870486-(O), LER-87-046, LER-87-46, NUDOCS 8709030005
Download: ML18004B912 (7)

Text

R JL RY INFORMATION DISTR 1 TI.SYSTEM (RIDS)ACCESSION NBR: 870IT'030005 DOC.DATE: 87/08/20 NOTARIZED:

NO FACIL: 50-400 Shearon Harris Nuclear Poujer Planti Unit 1I Carolina AUTH.NAME AUTHOR AFFILIATION SCHWABENBAUER Carolina Poujer 8i Light Co.WATSONI R.A.Carolina Poujer 8.Light Co.RECIP.NAME RECIPIENT AFFILIATION DOCKET 05000400

SUBJECT:

LER 87-046-00:

on 870722I main feedujater pump B tripped due to low floe resulting in automatic start of auxiliary feedujater pumps.Caused bg loose linkage on recirculation valve due to vibration.

Valve repaired.Procedures changed.W/870820 ltr.DISTRIBUTION CODE: IEEED COPIES RECEIVED:LTR f ENCL Q SIZE: TITLE: 50.73 Licensee Event Report<LER)I Incident Apt>etc.NOTES: Ap'plication for permit reneuJal filed.05000400 REC IP IENT ID CODE/NAME PD2-1 LA BUCKLEYr B INTERNAL: ACRS MI CHELSQN AEQD/DQA AEOD/DSP/ROAB DEDRO NRR/DEST/CEB NRR/DEST/I CSB NRR/DEST/MTB NRR/DEST/RSB NRR/DLPG/HFB NRR/DQEA/EAB N-/RPB ILE 02 DI J RQN2 FILE 01 EXTERNAL: EQ~oG GROHI M LPDR NSIC HARRISI J COP IES LTTR ENCL 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 2 2 1 1 1 1 5 5 1 1 1 1 RECIPIENT ID CODE/NAME-PD2-1 PD ACRS MQELLER AEOD/DSP/NAS AEOD/DSP/TPAB NRR/DEST/ADS NRR/DEST/ELB NRR/DEST/MEB NRR/DEBT/PSB NRR/DEST/SGB NRR/DLPG/GAB NRR/DREP/RAB NRR/PMAS/ILRB RES DEPY QI RES/DE/EIB H ST LOBBY WARD NRC PDR NSIC MAYBe G COPIES LTTR ENCL 1 1 2 2 1 1 1 0 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 43 ENCL 42

~0 NRC Form 388 (8.83)LICENSEE EVENT REPORT (LER)U.S.NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO.3)604104 EXPIRES: S/31/88 FACILITY NAME (II SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NUMBER (2)IIAGE 3 0 5 0 0 0 400 10FP 3 ("MAIN FEEDWATER RECIRCULATION FLOW CONTROL VALVE FAILED RESULTING IN A MAIN FEEDWATER PUMP'B'RIP ON LOW FLOW ACTUATING AUXILIARY FEEDWATER SYSTEM EVENT DATE (5)LER NUMBER (8)REPORT DATE (7)OTHER FACILITIES INVOLVED (8)MONTH OAY YEAR YEAR Er ry SEOUENTIAL NUMBER MONTH'&A NUMBER DAY YEAR FACILITY NAMES DOCKET NUMBER(S)0 5 0 0 0 0 7 2 28 787 0 4 6 0 0 0 8 2 0 8 7 0 5 0 0.0 OPEAATINQ MODE (8)POWER LEVEL p p 20A02(B)20.405(el(1)

(0.20A05(e)(1)(EI 20.405(el(1)(lll) 20AOS(e)ll)(lv)20.405(~)(1)(v)20.405(c)'0.38(c)0)50.38(cl (2)50.73(e)(2l(I)50.73(e)(2)III)50,73(e)(2)Bll)LICENSEE CONTACT FOR THIS LER (12I 50.73(el(20(v) 50.73(e)(21(vl 50.73(el(2)(vS)50.73(~)(2)(vill)(A) 50.73(~)(2l(vill)(BI 50,73(e)(2)(e)THIS REPORT IS SUBMITTED PUASUANT-T 0 THE REOUIREMENTS OF 10 CFR ()r (Check one or more of the folloryinpl (11 73.71(II)73.71(cl OTHER (Specify In Ahrtrect INIorNend In Teer, HRC Form 366A)NAME R.SCHWABENBAUER

-REGULATORY COMPLIANCE TELEPHONE NUMBER AREA CODE 9 193 62-26 69 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)CAUSE SYSTEM COMPONENT B S J F C MANUFA(r TURER M 2 0 EPORTABLE)8)CAUSE TO NPAOS SL<rC.r..:..rO....

SYSTEM COMPONENT MANUFACr TURER EPORTABLE TO NPRDS 0'"~@3..: SUPPLEMENTAL REPORT EXPECTED (14)YES Ilf yer, complete EXPECTED sU64IISSIOH DATE)X NO ABSTRACT (Limit to I400 rpecet, Ie., epprorrlmerery fifteen elnpre rpete tyPervrltren lintel (18)ABSTRACT EXPECTED SU 8 MISSION DATE (I SI MONTH OAY YEAR The plant was operating at 1 percent reactor power in Mode 2, Plant Start-up, on July 22, 1987.Only one Main Feedwater Pump,'B', was in service.'B'ain Feedwater Pump tripped on low-flow which caused the automatic start, as, required, of both motor driven Auxiliary Feedwater Pumps.The Auxiliary Feedwater Pumps started and ran as required to supply~ater to the steam generators.

Plant temperature and pressure remained stable at normal no load values.An operator subsequently started the'A'ain Feedwater Pump and secured the Auxiliary Feedwater Pumps.The cause of the low flow was investigated.

The Feedback linkage on the'B'eedwater Pump recirculation valve was found loose.This prevented the actuator from receiving a signal to open and caused the low flow condition for the'B'eedwater Pump.O OE2 a (x)o Ron.OO h (T)(X)O (A~OV OQ OQ 07<O O(): (x)a.(f)The root cause of the failure was vibration of the valve.The loose linkage on the Feed pump Recirculation valve was repaired.A plant maintenance checklist has been developed to monitor the recirculation valve Feedback linkages monthly to prevent a recurrence of this failure.A Plant Change Request was also generated to investigate and resolve the high vibration experienced by the recirculation valve.reRC Form 388 The event is reportable per 10CFR50.73 (a)(2)(iv) as an automatic actuation of u F ture Auxiliar Feedwater S stem).

NRC Form 366A (94LI)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCLEAR REGULATORY COMMISSION APPROVEO OMB NO.3150M)04 EXP)RES/8/3 I/88 FACILITY NAME (11 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 OOCKET NUMBER (2)YEAR LER NUMBER (6)$,/i SEQUENTIAL OLRI NUMBER REVISION NUMBER PAGE (31 TEXT///more Eoeoe)I/))rrBed, Iree ddlobnsl HRC Frnn 3$!143)(17)0 5 0 0 0 40 08 046 00 02 oF 0 DESCRIPTION:

The plant was operating at 1 percent reactor power in Mode 2, Plant Start-up, on July 22, 1987.Only one Main Feedwater Pump,'B', (EIIS:SJ)was in service at the time.A pump low-flow alarm was received in the Main Control Room and an auxiliary operator was dispatched to check the position of the recirculation valve, 1FW-39.(Masoneilan Valve 6 Actuator Model Number 37-40412-8A-6)..

-The'valve was reported to be approximately 50 percent open.At 0500 hours0.00579 days <br />0.139 hours <br />8.267196e-4 weeks <br />1.9025e-4 months <br />'B'ain Feedwater Pump tripped due to low flow.Both motor driven Auxiliary Feedwater Pumps (EIIS:BA)started as requi'red to supply water to the steam generators.

Reactor Coolant System (EIIS:AB)temperature and pressure,-

and Steam Generator (EIIS:SB)water levels remained stable at normal no load values.An operator subsequently started the'A'ain Feedwater Pump at 0534 hours0.00618 days <br />0.148 hours <br />8.829365e-4 weeks <br />2.03187e-4 months <br />.and secured the Auxiliary Feedwater Pumps.CAUSE't was first thought the pump tripped on instantaneous overcurrent as the flag on'C'hase for'B'ain Feedwater Pump was down.Electricians checked the breaker and found no indications of an electrical fault.It was concluded that the flag was caused by the vibration when the breaker tripped.The cause of the pump trip was the low flow trip of the'B'ain Feedwater Pump.The low flow resulted when the pump's recirculation valve did not respond to the signal to open.Instrument and Control technicians checked the'B'ain Feedwater Pump recirculation valve and found a loose feedback linkage which kept the actuator from opening the valve.As a result, the recirculation flow decreased below the pump's low flow trip setpoint.The linkage was repaired and the pump started and ran normally.It was concluded that vibration of the valve caused the loosening of the linkage.The high vibration is caused by t.he thruttling action of the valve.The differential pressure across the valve is approximately 1700 psi.The vibration in the recirculation valve line has caused several failures in the operation of the recirculation valve.A broken linkage was first identified during power ascension testing where the recirculation valve would not shut.Prior to another event (reported in LER 87-005-00), the air line to the valve actuator had broken off and failed the valve to the full open position.NRC FORM 3BBA rrr4 R*U S GPO 1986 0 824 538/455

NRC Fo<<tn 366A (983)LICENSEE EVENT REPORT (LER)TEXT CONTINUATION U.S.NUCLEAR REGULATORY COMMISSION APPROVED OMB NO.3150-0104 EXPIRES: 8/31/88 FACILITY NAME (1)SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 TEXT//mom RMBB/4 nqakaf, UBB////4/N/HRC

%%d/m SBSAS/(17)DOCKET NUMBER (2)o s o o o 40 0 YEAR 8 7 LER NUMBER (6)SEOUENTIAL NUMBER 0 6 REVISION NUMBER 00 03 PAGE (3)oF 0 ANALYSIS: This event is reportable per 10CFR50.73(a)(2)(iv) as an automatic actuation of the Auxiliary Feedwater System (AFW).There are no safety consequences as a result of this event.The Auxiliary Feedwater System started as required upon loss of Main Feedwater to maintain water.levels in the Steam Generators.

The Main Feedwater Pumps low flow trip is set at approximately 5000 gpm.Failure of the recirculation valve to open results in a pump trip at only relatively low power levels (0-15%).In this situation, the second Main Feed Pump is not running and the trip of one feed pump will automatically result in AFW actuation.

If AFW flow does not maintain Steam Generator Water levels, reduction in power and/or reactor trip may be required.Failure of the valve to remain closed at higher power levels can also produce a pump trip by increasing the pumps flow to runout conditions.

An event similar to this was reported in LER-87-037-00.

In this case, the worst consequences would occur at 100%power.Loss of one Main Feedwater Pump at this power level results in a Reactor Trip due to low Steam Generator water levels.CORRECTIVE ACTION: 1.The loose linkage on the Feed Pump Recirculation valve was repaired.E Action to Prevent Recurrence:

1.A plant maintenance checklist has been developed to monitor the recirculation valve Feedback linkages monthly to ensure they are in working condition.

2.A Plant Change Request (PCR-1829) is being generated to look at changing out the valve trim on the Feed pump recirculation valve ard/o.installing a breakdown orifice ahead of the valves.The purpose of this is to reduce the pressure drop in the area of the valve, therefore reducing vibration in the area.NRC FORM SBBA)4-RAI w U.S GPO:1986 0 624 538/455 Carolina Power 8,Light Company HARRIS NUCLEAR PROJECT P.O.Box 165 New Hill, NC 27562'AUG 20 3987 File Number: SHF/10-13510C Letter Number'HO-870486 (0)U.S.Nuclear Regulatory Commission ATTN: NRC Document Control Desk Washington, DC 20555 SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 DOCKET NO.50-400 LICENSE NO.NPF-63 LICENSEE EVENT REPORT 87-046-00 Gentlemen'.

In accordance with Title 10 to the Code of Federal Regulations, the enclosed Licensee Event Report is submitted.

This report fulfills the requirement for a written report within thirty (30)days of a reportable occurrence and is in accordance with the format set forth in NUREG-1022, September, 1983.RAW:dj Enclosure Very truly yours, Egcc/~R.A.Watson Vice President Harris Nuclear Project cc.'Dr.J.Nelson Grace (NRC-RII)Mr.B.Buckley (NRR)Mr.G.Maxwell (NRC-SHNPP)MEM/HO-8704860/1/Osl