ML18005A809

LER 89-003-00:on 890206,shaft of Main Feedwater Pump a Sheared,Causing Sudden Reduction in Feedwater Flow to Steam Generators & Pump Trip.Caused by Corrosion in Shaft.Pump & Local Components repaired.W/890308 Ltr

ML18005A809
Person / Time
Site:	Harris
Issue date:	03/08/1989
From:	Howe A, Watson R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HO-890028-(O), LER-89-003-02, LER-89-3-2, NUDOCS 8903210164
Download: ML18005A809 (5)

Text

AC CELE RATED D1S1BUTl ON DE M ON STRON SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:8903210164 DOC.DATE: 89/03/08 NOTARIZED: NO DOCKET FACIL:50-400 Shearon Harris Nuclear Power Plant, Unit 1, Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION HOWE,A.J. Carolina Power & Light Co.

WATSON,R.A. Carolina Power & Light Co.

RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 89-003-00:on 890206,reactor trip on low steam generator level occurred due to main feedwater pump shaft failure.

W/8 ltr.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR ENCL SIZE:

TITLE: 50.73 Licensee Event Report (LER), Incident Rpt, etc.

NOTES:Application for permit renewal filed. 05000400 /

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 1 PD2-1 PD 1 1

-BECKER,D --1 1 INTERNAL: ACRS MICHELSON 1 1 ACRS MOELLER 2 2 ACRS WYLIE 1 1 AEOD/DOA 1 1 AEOD/DS P/TPAB 1 1 AEOD/ROAB/DS P 2 2 ARM/DCTS/DAB 1 1 DEDRO 1 1 NRR/DEST/ADE 8H 1 - 1 NRR/DEST/ADS 7E 1 0 NRR/DEST/CEB 8H 1 -

1 NRR/DEST/ESB 8D 1 1 NRR/DEST/ICSB 7 1 1 NRR/DEST/MEB 9H 1 1 NRR/DEST/MTB 9H 1 1 NRR/DEST/PSB 8D 1 1 NRR/DEST/RSB 8E 1 1 NRR/DEST/SGB 8D 1 1 NRR/DLPQ/HFB 10 1 1 NRR/DLPQ/QAB 10 1 1 NRR/DOEA/EAB 11 1 1 NRR/DREP/RAB 10 1 1 NRR/DREP/RPB 10 2 2 NRR IB 9A 1 1 NUDOCS-ABSTRACT 1 1 02 1 1 RES/DSIR/EIB 1 1 -E&/.BS~* 1 1 RGN2 FILE 01 1 1 EXTERNAL EG&G WILLIAMSI S 4 4 FORD BLDG HOY, A 1 1 H ST LOBBY WARD 1 1 LPDR 1 1 NRC PDR 1 1 NSIC MAYS,G 1 1 NSIC MURPHYIG A ~ 1 1 D

NOTE 'IO ALL "RIDS" RECIPZEPIS:

S PIZASE HELP US 'IO RECCE WASTE! CGNI'ACT %HE DOCUM~ CGNI'ROL DESKS ROOM Pl-37 (EXT. 20079) IO ELIMINATE YOUR NME PRCH DISTIKBUTION LZSTS FOR DCCUMEHIS YOU DON'T NEEDf TOTAL NUMBER OF COPIES REQUIRED: LTTR 45 ENCL 44

NRC Formr366 U.S. NUCLEAR REQULATORY COMMISSION (94)3)

APPROVED OMB NO. 3160010(

EXPIRES? 8/31/88 LICENSEE EVENT REPORT tLER)

DOCKET NUMBER (2) I?A E 3 FACILITY NAME (I)

SHEARON HARRIS NUCLEAR POWER PLANT UNIT ONE 0 5 0 0 04 00 1 OFO 3 REACTOR TRIP ON LOW STEAM GENERATOR LEVEL DUE TO MAIN FEEDWATER PUMP SHAFT FAILURE EVENT DATE 16) LER NUMBER (6) REPORT DATE IT) OTHER FACILITIES INVOLVED ISI MONTH DAY YEAR YEAR SEQUENTIAL REVAMP MONTH DAY YEAR FACILITYNAMES DOCKET NUMBER(SI NUMBER ?Pi: NUMBER 0 5 0 0 0 0 2 06 89 9 0 3 0 00 30 8 8 9 0 5 0 0 0 OPERATING THIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR (): ICnecrr one or more of tne forlovfrnBI (Ill MODE (9) 50 73(el(2)(l') 73.71(B) 20A02(ol 20A05(cl X POWER 20AOS(e HI I (I) 50.38 (c) (I ) 50.73( ~ l(2)(vl 73.71(c)

LEVEL 20AOS(el(1)(lll 50.36(c) (2) 50.73(e)12) (vll) QTHER lspeclftr In Aortrect (10) 1 0 0 6 low enrf In Text, NRC Forrrr

'~7'~P'++8 20AOB( ~ l(1)(lll) 50.73(e l(2)(l) 50.73(e) (2)(vill)(A) BBBAI 20AOS(e ) (1)(I v) 50.73(e) (2) (II) 50,73(e) (2)(vill)(Bl 20AOS(e) (I ) (v) 50.73(e) (2)(lll) 50.73(e) (21(el LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE Andrew J. Howe Senior Specialist 91 936 2-2 719 COMPLETE. ONE. LINE, FOR SACK COMPONENT EAILURE DESCRIBED IN THIS REPORJ ()3) liilANUFAC REPORTABLE MANUFAC. REPORTABLE CAUSE SYSTEM COMPONENT TO NPRDS CAUSE SYSTEM COMPONENT TURER TO NPRDS TURER Vk.(le%('~

A S J P I075 A S J CP LG Z01 Y ~+%2k e~i::: ni. Y)4 SUPPLEMENTAL REPORT EXPECTED (I el MONTH DAY YEAR EXPECTED SU 8 M I SS ION DATE (16)

YES llfyer, complNe EXPECTED SUBMISSION DATEI X NO ABSTRACT (Limit tO ICOO rpecer, Ie., epproximerely flfrern rlnplecpece rvpewrlnen llnnl (16)

On February 6, 1989, with the plant operating at 100X power, at 0008 the shaft of the A Main Feedwater Pump (MFP) sheared, causing a sudden reduction in feedwater flow to the steam generators. Within seconds the MFP tripped, causing a turbine runback. The operators took manual control of the feedwater regulating valves and attempted to raise steam generator levels, but the reactor tripped on low steam generator level approximately one minute after the transient began. The plant response to the reactor trip was normal, with all auxiliary feedwater pumps automatically starting to maintain steam generator levels, and the operator manually closing the main steam isolation valves to control the primary plant cooldown. The main generator exciter field breaker did not trip open, and was observed to be smoking. The breaker was locally opened and an extinguisher used on the breaker to prevent ignition. The exciter field breaker was found to have a burned out trip coil which was subsequently repaired.

The MFP shaft was found to be sheared near the coupling between the pump and the coupling. The damaged shaft was sent to a company laboratory, and the preliminary cause was determined to be long term cyclic fatigue. The event caused internal damage to the pump motor, as well as minor missile damage to components in the near vicinity.

Prior to plant restart, the undamaged B MFP shaft keyway was examined and found to be in satisfactory condition. The plant was restarted and brought to approximately 60X power on February 9. Repairs were completed to the A MFP and the nearby components on February 14, and the plant was returned to full power operations. The final results of the examination of the failed shaft will be used to determine any necessary long term corrective actions.

-: )0321(.1 I 6E) Bct'03O'=(

PL(I," ADI (CK VGOO(.)4OO NRC Form 368 I"I.)C (9 83)

I U.S. NUCLEAR RECULATORY COMMISSION NRC FAIm 355A (94LT(

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVED OMS NO. 3(50M(04 EXPIRES: 5/31/SS FACILITY NAME (1l OOCKET NUMSER (2l LER NUMSER (Sl PACE (31

(>Xy SEOUENV/AL 2N AKVdION SHEARON HARRIS NUCLEAR POWER PLANT YEAR NI/M ER ~ +I NVM UNIT 1 o s o o o 4 0 8 9 0 3 0 0 20F 0 3 TEXT /////Ave A/Mcf lf /PFMPN/, vff adWdavW H/IC FomI 35543/ (17(

EVENT DESCRIPTION On February 6, 1989, the plant was operating at full. power, 885 net MWe. At 0008:57, main control. room alarms were received indicating a steam/feedwater flow mismatch, and a loud explosive sound was heard in the main control room, followed by the sound of the unloading of an electric motor. Within seconds, the A Main Feedwater Pump (MFP) (EIIS:SJ:P) (Manufacturer Ingersoll-Rand, model number 16X19CA) tripped, initiating a runback of the main turbine

,(EIIS:TA). The operators in the control room took manual control of the main feedwater regulating valves (EIIS:SJ) to maximize .feedwater flow from the operating B MFP in order to control steam generator levels. At 0009:24, approximately one half minute after the transient began, one of the two heater drain pumps (EIIS:SN) tripped, and at 0010:05, a reactor trip occurred on low steam generator leveL.

The plant response- to'"the reactor trap was as expected. The B MFP trzppe shortly after the reactor trip due to low flow occurring when the main feedwater regulating valves automatically closed on interlock at a Reactor Coolant System average temperature of 564'F. All three auxiliary feedwater pumps (EIIS:BA) started automatically to control steam generator. Levels, and the operator manually closed the main steam isolation valves (EIIS:SB) to limit the cooldown of the primary. The main generator exciter field breaker (EIIS:TL) failed to trip open, and was found to be smoking. The breaker is located in the Turbine Building switchgear room, and an operator discovered the situation while entering the room to locally trip the A MFP Lube oil pump breaker. No safety related equipment is located in that area. The operator tripped the breaker and used a hand-held extinguisher to ensure no ignition occurred. Upon investigation, the breaker was found to have burned out trip coil. The plant was stabilized in Mode 3 at approximately 557'F.

Shortly after the transient began, an operator locally observed smoke and steam in the vicini(.y of the A MFP motor to pump coupling (EIIS:SJ:CPLG).

Minor missile damage was apparent to piping and conduit in the area. The pump shaft was stopped and the motor was turning rapidly. After coastdownf the pump began to turn slowly due to recirculation flow'this flowpath was isolated and the pump was secured. Damage to the pump motor occurred due to its rotation with an unbalanced, unsupported coupling.

The shaft between the MFP coupling and pump was sheared and a crack beginning at the root of the keyway that attaches the pump shaft to the coupling was observed. The shearing of the shaft caused the coupling to come loose, which subsequently generated missiles, causing minor damage to components in the local vicinity. The high motor vibration sheared a lubrication oil line to the rear motor bearing (EIIS:SK), and caused further piping damage There were no personnel injuries as a result of these events, and the damage was confined to the local. vicinity.

NRC FORM 3FSA *U.S OPO.1055 0 024 535/455 (04131

NAC Force 3$ 8A U.S. NVCLEAA REOULATORY COMMISSION 10831 LICENSEE EVENT REPORT ILER) TEXT CONTINUATION APPROVED OMS NO, 3150-0104 EXPIRES: 8/31/88 FACILITY NAME 111 DOCKET NUMSER 121 LEA NVMSEA LSI FACE (31 SHEARON HARRIS NUCLEAR POWER PLANT yEAR I bo SEQUENTIAL NUM ER Eo mfysEIQN 4:: NVMEESS UNIT ONE

~~////CHIC 0 5 0 0 0 4 0 0 89 00 3 0 0 0 3 oF 0 3 TEXT///~EFEtd N~ 3//SAE/IIII CAUSE The shaft and coupling were removed and sent to a company laboratory for examination. The preliminary results indicated that a crack covering approximately 2/3 of the shaft cross-sectional area had existed for a period of time prior to the sudden failure. This area showed discoloration due to corrosion. The cause of this crack is believed to be long term cyclic fatigue. Vibration readings from the pump are routinely obtained, and these readings showed no adverse trends prior to this event.

The B MFP was subsequently examined to ensure that no similar cracks existed, The results of this examination were satisfactory, and the B MFP was returned to service. The plant was restarted and brought to approximately 60K power on February 9. Repairs to the A MFP and other components damaged by the shaft failure were completed on February 14, and the~lant resumed normal fully power operation.

SAFETY SIGNIFICANCE There were no safety consequences as a result of this event. The plant responded as designed following the reactor trip, with the actuation of auxiliary feedwater to maintain steam generator levels.

This event is reportable as an actuation of the reactor protection system and engineered safeguards systems per 10CFR50.73(a)(2)(iv). There have been no previous similar events involving the shearing of a pump shaft due to cyclic fatigue. I CORRECTIVE ACTIONS The B MFP shaft keyway was inspected to ensure no similar faults existed prior Lo returning the pump to service on February 9.

2~ The A MFP and damage to local components in its vicinity were repaired and the new shaft keyway examined, and the pump was returned to service on February 14.

3. Upon completion of the investigation to determine the failure mechanism of the sheared, shaft, long term actions to prevent recurrence will be determined and implemented as necessary.

NRC FQ/IM 3EEA mU.S 0/s0.1088 0 824 538/455 10831

Ce~~

Carolina Power 8 Light Company MAR 8 NS HARRIS NUCLEAR PROJECT P.O. Box 165 New Hill, NC 27562 File Number'SHF/10-13510C Letter Number'HO-890028 (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 89"003-00 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, R. A. Watson Vice President Harris Nuclear Project AJH:tbb Enclosure cc: Mr. R. A. Becker (NRR)

Mr. W. H. Bradford (NRC SHNPP)

Mr. S. D. Ebneter (NRC RII)

MEM/LER-89-003/1/OS1