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 DOCKET FACIL: 50-400 Shearon Harris Nuclear Poujer Planti Unit 1I Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION SCHWABENBAUER Carolina Poujer 8i Light Co.

WATSONI R. A. Carolina Poujer 8. Light Co.

RECIP. NAME RECIPIENT AFFILIATION

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 TITLE: 50. 73 Licensee Event Report <LER)I Incident Apt> etc.

ENCL Q SIZE:

NOTES: Ap'plication for permit reneuJal filed. 05000400 REC IP IENT COP IES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 1 -PD2-1 PD 1 1 BUCKLEYr B 1 1 INTERNAL: ACRS MICHELSQN 1 1 ACRS MQELLER 2 2 AEQD/DQA 1 1 AEOD/DSP/NAS 1 AEOD/DSP/ROAB AEOD/DSP/TPAB 1 DEDRO 1 NRR/DEST/ADS 1 0 NRR/DEST/CEB 1 1 NRR/DEST/ELB 1 NRR/DEST/ I CSB 1 1 NRR/DEST/MEB NRR/DEST/MTB 1 NRR/DEBT/PSB 1 1 NRR/DEST/RSB 1 NRR/DEST/SGB 1 NRR/DLPG/HFB 1 1 NRR/DLPG/GAB 1 1 NRR/DQEA/EAB 1 1 NRR/DREP/RAB 1 1 N - /RPB 2 2 NRR/PMAS/ ILRB 1 ILE 02 1 RES DEPY QI 1 DI J 1 RES/DE/EIB 1 1 RQN2 FILE 01 1 1 EXTERNAL: EQ~oG GROHI M 5 5 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC HARRISI J 1 1 NSIC MAYBe G 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 43 ENCL 42

~0 U.S. NUCLEAR REGULATORY COMMISSION NRC Form 388 (8.83) APPROVED 0MB NO. 3)604104 EXPIRES: S/31/88 LICENSEE EVENT REPORT (LER)

DOCKET NUMBER (2) IIAGE 3 FACILITY NAME (II SHEARON HARRIS NUCLEAR POWER PLANT UNIT 1 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)

Er ry SEOUENTIAL DAY YEAR FACILITYNAMES DOCKET NUMBER(S)

MONTH OAY YEAR YEAR NUMBER '&A NUMBER MONTH 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 THIS REPORT IS SUBMITTED PUASUANT-T0 THE REOUIREMENTS OF 10 CFR ()r (Check one or more of the folloryinpl (11 OPEAATINQ MODE (8) 20A02(B) 20.405(c) 50.73(el(20(v) 73.71(II) 20.405(el(1) (0 0) '0.38(c) 50.73(e)(21(vl 73.71(cl POWER LEVEL 50.73(el(2) (vS) OTHER (Specify In Ahrtrect p p .20A05(e) (1)(EI 50.38(cl (2)

INIorNend In Teer, HRC Form 20.405(el(1)(lll) 50.73(e) (2l(I) 50.73( ~ )(2)(vill)(A) 366A) 20AOS(e) ll) (lv) 50.73(e) (2) III) 50.73( ~ ) (2l(vill)(BI 20.405( ~ )(1)(v) 50,73(e) (2) Bll) 50,73(e) (2)(e)

LICENSEE CONTACT FOR THIS LER (12I NAME TELEPHONE NUMBER AREA CODE R. SCHWABENBAUER REGULATORY COMPLIANCE 9 193 62 -26 69 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT (13)

MANUFA(r EPORTABLE 8 MANUFACr EPORTABLE CAUSE SYSTEM COMPONENT CAUSE SYSTEM COMPONENT TURER TO NPAOS ) ) TURER TO NPRDS SL<rC. r ..:..rO....

0' "~@3..:

B S J F C M 2 0 MONTH OAY YEAR SUPPLEMENTAL REPORT EXPECTED (14) EXPECTED SU 8 MISSION DATE (I SI YES Ilfyer, complete EXPECTED sU64IISSIOH DATE) X NO ABSTRACT (Limit to I400 rpecet, Ie., epprorrlmerery fifteen elnpre rpete tyPervrltren lintel (18)

ABSTRACT 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.

Feedwater Pump tripped on low-flow which caused the automatic start, as,

'B'ain 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.

O The cause of the low flow was investigated. The Feedback linkage on the Pump recirculation valve was found loose. This prevented the Ron.a

'B'eedwater OE2 (x) o actuator from receiving a signal to open and caused the low flow condition for OO h (T) the 'B'eedwater Pump.

(X) O (A~ The root cause of the failure was vibration of the valve. The loose linkage OV on the Feed pump Recirculation valve was repaired. A plant maintenance OQ monitor the recirculation valve Feedback OQ checklist has been developed to 07<

O linkages monthly to prevent a recurrence of this failure. A Plant Change Request was also generated to investigate and resolve the high vibration O():

experienced by the recirculation valve.

(x)a.(f)

The event is reportable per 10CFR50.73 (a)(2)(iv) as an automatic actuation of u F ture Auxiliar Feedwater S stem).

reRC Form 388

NRC Form 366A (94LI) U.S. NUCLEAR REGULATORY COMMISSION LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO. 3150M)04 EXP)RES/ 8/3 I/88 FACILITYNAME (11 OOCKET NUMBER (2)

LER NUMBER (6) PAGE (31 SHEARON HARRIS NUCLEAR POWER PLANT YEAR $,/ i SEQUENTIAL REVISION OLRI NUMBER NUMBER UNIT 1 TEXT ///more Eoeoe )I /))rrBed, Iree ddlobnsl HRC Frnn 3$ !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 tripped on instantaneous overcurrent as the flag on 'C'hase for 'B'ain pump 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 U.S. NUCLEAR REGULATORY COMMISSION (983)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMB NO. 3150-0104 EXPIRES: 8/31/88 FACILITY NAME (1) DOCKET NUMBER (2) LER NUMBER (6) PAGE (3)

YEAR SEOUENTIAL REVISION SHEARON HARRIS NUCLEAR POWER PLANT NUMBER NUMBER UNIT 1 o s o o o 40 0 8 7 0 6 00 03 oF 0 TEXT //mom RMBB /4 nqakaf, UBB ////4/N/HRC %%d/m SBSAS/ (17)

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 w U.S GPO:1986 0 624 538/455

)4-RAI

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.

Very truly yours, Egcc/~

R. A. Watson Vice President Harris Nuclear Project RAW:dj Enclosure cc.'Dr. J. Nelson Grace (NRC RII)

Mr. B. Buckley (NRR)

Mr. G. Maxwell (NRC SHNPP)

MEM/HO-8704860/1/Osl