ML18004B762

LER 87-012-00:on 870311,turbine & Reactor Trips Occurred During Troubleshooting at Main Turbine Supervisory Control Panel.Turbine Trip Caused by Depressing Test Push Button on Turbine Supervisory Control panel.W/870410 Ltr

ML18004B762
Person / Time
Site:	Harris
Issue date:	04/10/1987
From:	Howe A, Watson R CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HO-870404-(O), LER-87-012, LER-87-12, NUDOCS 8704140499
Download: ML18004B762 (5)

Text

REGULATORY INFORMATION DISTRIBUTIO SYSTEM (RIDB)

J

-ACCESSION NBR 8704140499 DOC. DATh,: 87/04/10 NOTARIZED: NO DOCKET I FAC IL: 50-400 Sheav'on Hav v is Nucleav Pouer Planti Unit ii Cav olina 05000400 AUTH. NAME AUTHOR AFFILIATION HOWE'. Carolina Powev h Ligh+ Co.

WATSON'. A. Cav olina Power 8< Light Co.

RECIP. NAME RECIPIENT AFFIl IATIG'A

SUBJECT:

LER 87-012-00: on 8703iii turbine +v ip 8< v eactov'rip occurred duving tvoubleshooting at'main turbine supervisory control panel. Cause unknown. Duv ing subsequent outage binding problem in v otov position v epaiv ed. W/870410. ltv.

DISTRIBUTION CODE: IE22D COPIES RECEIVED: LTR ENCL SIZE:

50. 73 Licensee Event Repov t (LER)i Incident Rpti etc. 'ITLE:

NOTES: Application for pevmit v enewal filed. 05000400 RECIPIENT COPIES RECIPIENT COP IEB ID CODE/NAME LTTR Ef",CL ID CODE/NAME LT TR Er'C L r D2-1 LA 1 1 PD2-1 PD 1 1 BUCKLEY B 1 INTERNAL: ACRB MICHELSON 1 ACRB MOELLER 1 1 ACRS WYLIE 1 AEOD/DOA AEOD/DSP/ROAB 2 2 AEOD/DSP/TAPB 1 NRR/ADT 1 1 hRR/DEBT/ADE 0 NRR/DEBT/ADS 1 0 VFRR/DEBT/CEB 1 NRR/DEST/ELB 1 ERR /DEST/ I CSB 1 1 NRR/DEST/MEB 1 1 NRR/DEST/MTB 1 1 NRR/DEST/PBB 1 1 h!RR/DEBT/RSB 1 NRR/DEST/SGB 1 1 NRR/DLPG/HFB 1 NRR/DLPG/GAB 1 1 h!RR/DOEA/EAB 1 NRR/DREP/EPB 1 1 VRR/DREP/RAB 1 NRR/DREP/RPB 2 2 /ILRB 1 1 NRR/PMAS/PTSB 1 02 1 1 REB SPEIB, T 1 RGN2 FI LE 0] 1 EXTERNAL; EGKG GROH> M 5 5 H BT LOBB Y WARD 1 1 LPDR 1 NRC PDR 1 1 NSIC HARRIS, J NBIC MAYSi G 1 TOTAL NUMBER OF COPIES REQUIRED: LTTR 43 ENCL 41

NRC Form 355 V.S. NUCLEAR REOULATORY COMMISSION 1843) APPROVED OMB NO. 3160010C EXPIRES: BI31I88 LICENSEE EVENT REPORT HLER)

FACILITY NAME (1) DOCKET NUMBER (2) PA E 3 Shearon Harris Plant Unit 1 o 5 o o o40 1 OF 0 TITLE (C)

Reactor Trip During Turbine Rotor Instrumentation Testing EVENT DATE IS) LEA NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

MONTH DAY YEAR YEAR ~8 SEOVENTIAL NUMBER REVISION MONTH NUMBER OAY YEAR FACILITYNAMES DOCKET NUMBEAISI 0 5 0 0 0 0 311 878 7 012 00 04 1087 0 5 0 0 0 THIS REPOAT IS SUBMITTED PURSUANT T 0 THE REQUIREMENTS OF 10 CF R g: JCneck one or more ol the IOllovtlnFJ (11 OPERATINQ MODE (8) 1 20A02(bl 20A06(c) X 60.73(e)(2)(iv) 73.71(5)

POWER 20AOS( ~ l(1)(il SOM Icl (1) 60.7 3(e) (2) (v) 73.71(cl LEVEL 0 20A05( ~ l(1)(ill 50.38(c)(2) 60 73(e) (2) (vti) oTHER Ispeclly in Aortrect oelovrend In Text, HRC Form 20AOS( ~ l(l) (III) ~ l(2)(il '0.73(

60.73(e) (2) (viii)IA) 3ESAJ 20AOS(e) (1)(iv) 60.73( ~ l(2) iii) 50.73(e) (2)(viii)IB) 20AOS(e)(1)(vl 60.7 3( ~ ) (2) (III) 60.73( ~ ) (2)(x)

LICENSEE CONTACT'OR THIS LEA (12)

NAME TELEPHONE NUMBER 919 362 -27 19 AREA CODE Andrew Howe/Engineer Regulatory Compliance COMPLETE ONE LINE FOA EACH COMPONENT FAILVAE DESCRIBED IN THIS REPORT (13)

MANUFAC. EPORTABLE COMPONENT MANUFAC. EPOATABLE CAUSE SYSTEM COMPONENT TO NPADS CAUSE SYSTEM TURER TURER TO NPRDS SUPPLEMENTAL REPORT EXPECTED (TC) MONTH OAY YEAR EXPECTED SUBMISSION DATE (16)

YES IIIyer, complere EXPECTED SUSMISSIDH DATE) ~ ~

X NO ABSTRACT ILlmlt ro Jcoo rptcer, I e.. epproxlmetely Ilftern tingle rpece typevvrinen linetJ (15)

At 1700 on March 11, 1987, with the plant operating at 47X thermal power level (370 MMe), a turbine trip and reactor trip occurred during troubleshooting at the main turbine supervisory control panel .

Subsequent to the reactor/turbine trip, the operating main feedwater pumps tripped actuating an automatic start of both motor-driven auxiliary feedwater pumps. Also the main steam line isolation valves were manually closed to limit the cooldown transient on the Reactor Coolant System (RCS). The plant was stabilized in Mode 3 at 5570F RCS average temperature (zero-load value).

The turbine trip was determined to be caused directly by depressing a test push button at the turbine supervisory control panel. The plant was returned to service on March 12, 1987.

870+iooo99 870ml0 PDR ADOCK 05000400 S PDR NRC Form 385 to.ne I

NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (943)

LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO. 3I50-OI04 EXPIRES: 8/3(/88 FACILITYNAME (Tl OOCKET NUMBER (2) LER NUMBER (61 PAGE (3)

YEAR

'v': SEOUENTIAL REVISION k4: NUMSER ging NUM ER Shearon Harris Plant Unit 1 o 5 o o o 40 087 012 0 02 DF 03 TEXT ////rroro g>>co /d Iq/o/ror/, Irw odr//I/or>>/HRC Form 36843/ (17)

Descri tion of Event On March 11, 1987, the plant was being operated at 47X thermal power level and 370 MWe generator load. During the day, while the turbine power was being increased, a "TURBINE TROUBLE" annunciator was being received intermittently. This alarm was being actuated by the turbine rotor position circuit, and each time the alarm was received, turbine loading was halted to allow for equilibration of the thermal expansion of the rotor. At approximately 1650, the alarm was again received and investigated; a test push button was actuated on the turbine supervisory control panel to check the functioning of the rotor position indicator. This push button also functions as a test for actuation of the turbine trip function for rotor position and a turbine trip occurred, initiating a reactor trip.

Prior to the events, both condensate pumps 1A and 1B, both condensate booster pumps 1A and 1B, main feedwater pump 1B, and both heater drain pumps lA and 1B were in service. Immediately following the reactor trip, only the 1B condensate pump and the 1A heater drain pump remained in service. The trip of the operating main feedwater pump caused automatic start of both auxiliary feedwater pumps. Full auxiliary feedwater flow and the low decay heat of the.

core resulted in a cooldown of the RCS to approximately 540'F, and the operator manually closed the main steam line isolation valves in an attempt to limit the cooldown.

The plant was stabilized in Mode 3 at an RCS Tavg of 557'F which is the zero-load value.

Plant Desi n Turbine rotor position is constantly monitored by the turbine supervisory instrumentation system since excessive movement of the rotor is indicati:ve of a failure of the turbine rotor thrust bearing. During normal operation as electrical load is changed, the resultant changes in turbine torque cause small variations in the axial displacement of the rotor. Excessive changes indicating wear of the thrust bearing will cause the rotor position monitor to alarm and further increases will actuate a trip of the turbine.

NRC FORM 366A mU.B.GPO:1988.0 824 538/455 (983)

NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION (943 l LICENSEE EVENT REPORT (LER) TEXT CONTINUATION APPROVEO OMB NO. 3150-0101 EXPIRES: 8/31/88 FACILITY NAME ('ll DOCKET NUMBER (2l LER NUMBER (6) IeAGE (3)

YEAR .'Pz'I SEOUENTIAL "e> REVISION NUMBER '31 NUMBER

.Shearon TEXT Wm<<o <<>>oa/I ~

Harris Plant Unit um ~///IC r 1

3//I/A3/(IT(

0 5 0 0 0 4 p p OF Cause Investigation of the rotor position alarms being received during the load increases revealed that the sensing probe was inproperly positioned, resulting in erroneous rotor position indications and alarms. This mispositioning was caused by binding of the sensing probe during the performance of OPT-1509, Turbine Trips Test, which was last performed on March 10, 1987. (The binding of the probe led to the troubleshooting and eventual trip, however, the mispositioned probe was not a direct cause of the trip).

The test circuits which actuated the turbine trip was investigated by CP&L and Westinghouse personnel, and it was determined that actuation of the rotor position test circuit should cause a turbine trip. Plant documentation concerning this test circuit does not conclusively state that fact, and the operator was not aware that a trip would occur.

The cause of the trips of the various condensate and feedwater pumps is the subject of ongoing investigations by CP&L.

~Anal sis There was no safety consequences resulting from this event. The Reactor Protection System and Auxiliary Feedwater System responded as required.

Normal recovery followed the reactor trip.

This event is reportable under 10CFR50.73(a)(2)(iv) as an actuation of the Engineered Safeguards Features Actuation and Reactor Protection Systems.

Corrective Action.'.The test push button on the turbine supervisory control panel has been temporarily disabled to prevent recurrence while the panel design is reviewed.

2.During a-subsequent outage, the binding problem in the rotor position probe was repaired.

3.Procedure OPT-1509 is being reviewed for possible changes to account for resetting the rotor position sensing probes.

4.Procedure OP-131.05, Digital Electrohydraulic System is being revised to include details on the controls and instruments of the supervisory control panel.

NRC FORM 366A o U.S.GPO:1986 0.821 538/155 esse

HARRIS NUCLEAR PROJECT P.O. Box 165 New Hill, NC 27562 APR 1 0 i98/

File Number'SHF/10-13510C Letter Number'. HO-870404 (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 87-012-0 Gentlemen.'n 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 RAW:skm Enclosure cc'. Dr. J. Nelson Grace (NRC RII)

Mr. B. Buckley (NRR)

Mr. G. Maxwell (NRC SHNPP)

MEM/LER-87-012/PAGE 1/Osl