ML18010A719

LER 92-010-00:on 920717,automatic Turbine Trip & Reactor Trip Occurred Due to Loss of Condenser Vacuum.Caused by Failure of North Low Pressure Turbine Exhaust Boot Seal. Replacement of Boot Seals Completed on 920721.W/920814 Ltr

ML18010A719
Person / Time
Site:	Harris
Issue date:	08/14/1992
From:	Hinnant C, Verrilli M CAROLINA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
HO-920120, LER-92-010-02, LER-92-10-2, NUDOCS 9208180128
Download: ML18010A719 (5)

Text

ACCELERATED D'RIBUTlON DEMONST~WTlON SYSTEM .

REGULATORY INFORMATION DISTR lBUT ION SYSTEM (BIDS)

ACCESSION NBR: 9208180128 DOC. DATE: 92/08/14 NOTARIZED: NO DOCKET FACIL: 50-400 Shearon Harris Nuclear Power Plant> Unit li Carolina 05000400 AUTH. NAME AUTHOR AFFILIATION VERR ILLI~ M. CaT olina Power h Light Co.

- HINNANTiC. S. Cano1 ina Power 5 Li g h t Co.

REC IP. NAME RECIPIENT AFFILIATION

SUBJECT:

! ER 92-010-00: on 920717> automatic turbine trip I!~ reactor trip occurred due to loss of condenser turbine vacuum..Caused bg boot seal.

failure of north low pressure exhaust ltr.

Replacement of boot seals completed on 920721. 8/920814 DISTRIBUTION CODE: IE22T COPIES RECEIVED: LTR ENCL SIZE:

50. 73/50. 9 Licensee Event Report <LER)i Incident Rpt> etc.

'ITLE:

/

NOTES: Application For permit renewal f iled. 05000400 A

RECIPIENT COPIES RECIPIENT CQP IES D ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-1 LA 1 1 PD2-1 PD 1 1 D LEi N 1 INTERNAL: ACNM 2 2 ACRS 2 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 /DET/EMEB 7E 'RR 1 1 NRR/DLP 6/LHFB10 1 1 NRR/DLPG/LPEB 10 1 NRR IDQEAIQEAB 1 1 I NRR DREP /P RP B 1 1 2 2 NRR/DST/SELB BD 1 1 NRR/DST/8 ICBBH3 1 1 Rf GD 1 1 NRR/DST/SRXB SE 1 EG FILE 02 1 1 RES/DSIR/EI8 1 1 RGN2 FILE 01 1 1 EXTERNAL: EGu~G BRYCE~ J. H 2 2 L ST LOBBY NARD 1 1 NSIC MURPHY'. A 1 R NRC PDR 1 NSIC POORER W. 1 NUDOCS FULL TXT 1 D

NOTE TO ALL "RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE V'ASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM P 1-37 (EYT. 20079) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

FUl L TEXT CONVERSIQN RFQUIRED TOTAL NUMBFR OF COPIES REQUIRED: LTTR 31 ENCL 31

0, CIIL Carolina Power 8 Light Company P.O. Box 165 New Hill, N.C. 27662 C. S. HINNANT Generet Meneger - Heme Rent AUG 1 4 1992 Letter Number: HO-920120 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 92-010-00 Gentlemen:

ln,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 witkin thirty (30) days of a reportable occurrence and is in accordance with the format set forth in NUREG-1022, September 1983.

Very truly yours C. S. Hinnant General Manager Harris Nuclear Project MV:dmw Enclosure cc: Mr. S. D. Ebneter (NRC - RII)

Mr. N. B. Le (NRC - RII)

Mr. J. E. Tedrow (NRC - SHNPP)

Mr. G. E. Vaughn 170C41 MEM/LER92-010/1/OSl '

9208180128 920814 PDR

)P;r.P ADOCK 05000400 8 PDR

NRC y('eRM 386 U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0M B NO. 319)4)104 8 (84)9)

EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS t INFORMATION COLLECTION REOUEST: 50.0 HRS. FORWARD LICENSEE EVENT REPORT ILER) COMMENTS REGARDING BURDEN ESTIMATE TO THE RECORDS AND REPORTS MANAGEMENT BRANCH (P630), V.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31500104). OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (1)

Harris Nuclear

'hearon Power Plant Unit

//1'OCKET o 5 NUMBER (2(

o o o 400 10F PA E 0

TITLE (4)

Reactor Trip due to Low Pressure Turbine Exhaust Boot Seal Failure EVFNT DATE 15) LER NUMBER (6) REPORT DATE (7) OTHER FACILITIES INVOLVED (8)

Y~S SEOUENTiAL REVtbt0re DAY YEAR FACILITYNAMES DOCKET NUMBER(S)

MONTH DAY YEAR YEAR NUMbER NUMBER MONTH 0 5 0 0 0 0 7 1 7 9 2 92 01 0 0 0 0 814 92 0, 5 0 0 0 THIS REPORT IS SUBMITTED PURSUANT T 0 THE RLOUIREMENTS OF 10 CFR (I: IChecfr one or more Of the foffewinpl (11 Iv OPERATING Ill(ill MODE (8) 20.402 (b) 20.405 I c) X 50.73( ~ l(2) lirl 73.71 (b) 20.406( ~ l(1) (il 50.38(cl(1) 60.73( ~ l(2) Iv) 73.71(cl POWER LEYEL OTHER ISpecify in Abltrett 1 0 0 20.405( ~ ) 50.38 (c) (2) 50 73( ~ )(2)(viil below end in Trit, ffRC Form 20A05( ~ )ill(iiil 50.73( ~ ) l2)(i) .60.73(el(2)(viiil(A) 366AI 20A05(el(ll(ivl 50.73(el(2)(iil 50.73( ~ ) l2) lriiD (8 I 20.405(e)l1)(rl 60.73(e l(2)(iii) 60.73(el(2)(nl LICENSEE CONTACT FOR THIS LER (12)

NAME TELEPHONE NUMBER AREA CODE Michael Verrilli Specialist Regulatory Co'mpliance 91 936 2- 230 3 COMPLETE ONE LINE FOR EACH COMPONENT FAILURE DESCRIBED IN THIS REPORT l13)

MANUFAC. REPORTABLE MANUFAC EPORTABLE CAUSE SYSTEM COMPONENT CAUSE SYSTEM COMPONENT TVRER TURER TO NPRDS TO NPRDS M?..: 0%7eFB B S G E X J U06 6 Y nI~e&!3+j(M: ILTAPFIU SUPPLEMENTAL REPORT EXPECTED (14I MONTH DAY YEAR EXPECTFD SUBMISSION DATE (15)

YES Ilf yeL comPleN EXPECTED SVSMISSIDff DATEI NO ABSTRACT ILimlt to f400 epecet, ).e., epproiimetely fifteen elnple.tpete typewrinen lintel (18)

ABSTRACT:

On July 17,, 1992 at 1218 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.63449e-4 months <br />, an automatic turbine trip and reactor trip occurred due to low 'condenser vacuum. All safety systems functioned as required, including an automatic Auxiliary Feedwater System actuation on steam generator lo-lo level. One Main Steam safety valve (1MS-47) was also observed to open and reseat. Main control room personnel stabilized the plant in mode-3 at normal operating temperature and pressure using the appropriate emergency operating procedures. The cause of the low vacuum condition was a failure of the north low pressure turbine exhaust boot seal. The corrective action for this failure was to replace the entire boot seal on both low pressure turbines instead of the previously performed local repair. Replacement of the boot seals and satisfactory setpoint testing of 1MS-47 were completed on July 21, 1992 and the unit was placed back on line at 2045 on July 22, 1992.

This event is being reported in accordance with 10CFR50.73 (a)(2)(iv) as an unplanned Engineered Safety Feature and Reactor Protection System actuation.

NRC Fottn388(6419)

NRC FORM366A US, NUCLEAR REGULATORY COIEMISSION APPROVED OMB NO. 31500104 (64)9)

EXPIRES: 4/30/92 ESTIMATED BURDEN PER RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT ILER) INFORMATION COLLECTION REOUESTI 500 HRS. FORWARD COMMENTS REGARDING BURDEN FSTIMATE TO THE RECORDS TEXT CONTINUATION AND REPORTS MANAGEMENT BRANCH (F4130), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, OC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31504)104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, 00 20503.

FACILITY NAME 01 DOCKET NUMBER l2) LER NUMBER 16) PAGE 13) os: SEQUENTIAL REVISION YEAR NUMBER NUMBER Shearon Harris Nuclear Power Plant Unit f/1 0 5 0 0 0 400 2 0 1 0 00 02 QF0 TEXT /// moro soooo /4 ror/o)od, oso oddidorM///RC Form 36MB / l)2)

EVENT DESCRIPTION:

On July 17, 1992 the plant was operating in mode-1 at 100 percent power. At 1218 hours0.0141 days <br />0.338 hours <br />0.00201 weeks <br />4.63449e-4 months <br /> an automatic turbine trip and reactor trip occurred due to a loss of condenser vacuum. The transient immediately following the reactor trip caused an automatic actuation of all three Auxiliary Feedwater (AFW) pumps on lo-lo steam generator water level. The AFW pumps operated correctly and were then manually .secured by the control operator. Operators also observed that one safety valve (1MS-47) on the "B" Main Steam line (EIIS-SB) lifted for approximately six minutes following the trip, then rese'ated. This was caused by a pressure increase'in the Main Steam System following closure of the Main Steam Isolation Valves (MSIV's) with no vacuum present in the condenser. During the event, the control room staff had initial concerns that Main Steam System pressure never reached the safety valve setpoint of 1185 psig + 1%. Based on these concerns, 1MS-47 was declared inoperable until testing could be performed to verify the required setpoint. At approximately 1000 hours0.0116 days <br />0.278 hours <br />0.00165 weeks <br />3.805e-4 months <br /> on July 21, 1992 three separate setpoint verification tests were completed that proved the setpoint to be within the required band. Subsequent review of steam pressure strip charts revealed that pressure had reached the setpoint band for 1MS-47.

Replacement of the boot seals and testing of the safety valve was completed one July 21, 1992 and the unit was placed back on line at 2045 on July 22, 1992.

CAUSE:

The low condenser vacuum condition was created due to a failure of the north low pressure turbine exhaust boot seal (EIIS-SG, Manufacturer-Uniroyal). This seal is a fabric reinforced rubber expansion joint and appears to have failed due to routine fatigue caused by aging. This failure was similar to the one that occurred five days earlier and resulted in LER ¹92-007, but occurred in a different location on the boot seal and was not a result of inadequate repair methods. Following this incident it was determined that the entire boot seal would be replaced rather than performing an additional local repair, as was done after the first failure. The decision to perform a local repair following the July 12th failure was based on the fact that there was less than two months until the upcoming refueling outage at which time the entire boot seal would be replaced, repair time versus replacement time and vendor recommendations based on past repair success. Therefore, this repeat failure is not a result of inadequate corrective actions.

NRC Form 366A (669)

NAG FORM 366A U.S. NUCLEAR REGULATORY COMMISSION APPROVED 0MB NO. 31500)OO (689)

EXPIRES: SI30)92 ESTIMATED BURDEN PEA RESPONSE TO COMPLY WTH THIS LICENSEE EVENT REPORT ILER) INFORMATION COLLECTION REQUEST: SOJ) HRS. FORWARD COMMENTS REGARDING BURDEN ESTIMATE TO THE RECOADS TEXT CONTINUATION AND AEPORTS MANAGEMENT BRANCH (P430), U.S. NUCLEAR REGULATORY COMMISSION, WASHINGTON, DC 20555, AND TO THE PAPERWORK REDUCTION PROJECT (31504104), OFFICE OF MANAGEMENTAND BUDGET, WASHINGTON, DC 20503.

FACILITY NAME (11 DOCKET NUMBER (1) LER NUMBER LS) PAGE (3)

YEAR SSQVSNZIAL REVISION r NVMSS4 NVMSS4 Shearon Harris Nuclear Power Plant Unit 81 0 5 0 0 0 4PP 9 2 0 1 0 00 03 OF p3 TEXT IIImoro spoco 8 r)lrr)od, Iroo pddrrr'Pool AIRC Form 366AB) (17)

SAFETY SIGNIFICANCE:

There were no safety consequences as a result of this event. Safety systems functioned as required to place the plant in a safe condition.

CORRECTIUE ACTIONS:

1. 'eplacement of both low pressure turbine boot seals was completed on July 21, 1992.

2. Testing of 1MS-47 was completed on July 21, 1992.

Investigation will continue to ensure that other possible exhaust boot failure modes are considered. If a root cause other than routine fatigue is identified, this LER will be revised to include the additional information and corrective actions needed.

EIIS INFORMATION:

Condenser System SG Main Steam System SB NRC Form 366A (SJ)9)