ML18036B179

LER 93-002-00:on 930131,determined That MSIV on Ms Line C Found to Have Leakage in Excess of Ts.Cause Not Identified. Licensee Will Issue Followup Rept Detailing Corrective Actions within 30 days.W/930226 Ltr

ML18036B179
Person / Time
Site:	Browns Ferry
Issue date:	02/26/1993
From:	Austin S, Zeringue O TENNESSEE VALLEY AUTHORITY
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
LER-93-002, LER-93-2, NUDOCS 9303090430
Download: ML18036B179 (16)

Text

ACCEI.ERA"/AD DOCUMENT DIST~BVTION SYSTEM REGULARLY INFORMATION DISTR1BUTIO~YSTEM (RIDS )

ACCESSION NBR:9303090430 DOC.DATE: 93/02/26 NOTARIZED: NO DOCKET t FACIL".50-260 Browns Ferry Nuclear Power Station, Unit 2, Tennessee 05000260 AUTH. NAME 'UTHOR AFFILIATION AUSTIN,S.W. , Tennessee Valley Authority ZERINGUE,O.J. Tennessee Valley Authority RECIP.NAME RECIPIENT AFFILIATION

SUBJECT:

LER 93-002-00:on 930131,determined that MSIV on MS line C found to have leakage in excess of TS.Cause not identified.

Licensee will issue followup rept detailing corrective actions.W/930226 ltr.

.DISTRIBUTION CODE: IE22T COPIES RECEIVED:LTR ENCL SIZE:

TITLE: Bulletin Response (30,40,70 DKT)

NOTES:

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD2-4 1 1 HEBDON,F 1 1 ROSS,T. 1 1 INTERNAL: ACNW 2 2 ACRS 2 AEOD/DOA 1 1 AEOD/DSP/TPAB 1 AEOD/ROAB/DSP 2 2 NRR/DE/EELB 1 NRR/DE/EMEB 1 1 NRR/DORS/OEAB 1 NRR/DRCH/HHFBHE 1 1 NRR/DRCH/HICB 1 NRR/DRCH/HOLB 1 1 NRR/DRIL/RPEB 1 NRR/DRSS/PRPB 2 2 ~N g~D SA/SPLB 1 NRR/DSSA/SRXB 1 1 QBG PME 02 1 RES/DSIR/EIB 1 1 RGN2'ILE Ol 1 EXTERNAL: EG&G BRYCEgJ.H 2 2 L ST LOBBY WARD NRC PDR 1 1 NSIC MURPHYiG.A NSIC POOREiW. 1 1 NUDOCS FULL TXT NOTE TO ALL"RIDS" RECIPIENTS PLEASE HELP US TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION

'ISTS FOR DOCUMENTS YOU DON'T NEED!

FULL TEXT CONVERSION REQUIRED TOTAL NUMBER OF COPIES REQUIRED: LTTR 32 ENCL 32

Tennessee valley y ultto<<ty. post orace 8ox 2000. Decatur. Atabarna 35609.20Ã)

O. J. "Ike" Zeringue Vice President, Browns Ferry Nuctear Ptant FEB 26 1953 U.S. Nuclear, Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555

Dear Sir:

TVA BROWNS FERRY NUCLEAR PLANT (BFN) UNITS li 2, AND 3 DOCKET NOS. 50-259, 260, AND 296 FACILITY OPERATING LICENSE DPR-33, 52, AND 68 LICENSEE EVENT REPORT LER '50-260/93002 The-enclosed .report provides details concerning main steam line isolation valves exceeding allowable leakage during testing.

This report is submitted in accordance .with 10 CFR 50.73(a)(2)(ii).

Sincerely,

0. J. Zeringue Enclosure cc: See page 2 OBOO70 9303090430 'st30226 PDR ADOCK 05000260 S PDR

0 0

U.S. Nuclear Regulatory Commission FEB 26 1~93 cc (Enclosure):

INPO Records Center Suite 1500 1100 Circle 75 Parkway Atlanta, 'Georgia 30339 Paul Krippner American Nuclear Insurers Town Center, Suite 300S 29 South Main Street West Hartford, Connecticut 06107 NRC Resident Inspector .

Browns Ferry Nuclear Plant Route 12, P.O. Box 637 Athens, Alabama 35609-2000 Regional Administrator U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 2900 Atlanta, Georgia 30323 Thierry M. Ross U.S. Nuclear Regulatory Commission One White Flint, North 11555 Rockville Pike R'ockville, Maryland 20852

NRC Form 366 (6-89)

LICENSEE EVENT REPORT (LER)'pproved

. NUCLEAR REGULATORY COMMISSION OMB 'No. 3150-0104 Expires 4/30/92 FACILITY NAME (1) IOOCKET NUMBER (2) I PAGE Br owns Ferr Nuclear Plant BFN Uni t 2 050002 10F 0 TITLE (4) Main Steam Line Isolation Valves Exceeding Allowable Leakage During Testing.

EVENT DAY LER NUMBER 6 REPORT DATE 7 OTHER FACILITIES INVOLVED 8 I SEQUENTIAL IREVISIONI, I I FACILITY NAMES IDOCKET NUMBER(S MONTH DAY YEAR YEAR

' MBER N MBER MONTH DAY YEAR N/A I I I "I I I I 0 2 I

2 6 I

9 3 I

3 1 9 3 9 3 0 0 2 0 0 N A OPERATING ITHIS REPORT IS SUBMITTED PURSUANT TO THE REQUIREMENTS OF 10 CFR g:

MODE Check ne or more of 'the followin 11 N I20 402(b) I20.405(c) I50.73(a)(2)(iv) I73.71(b)

POWER I I20.405(a)(1)(i) I l50 36(c)(l) I50.73(a)(2)(v) I73.71(c)

LEVEL I I20.405(a)(l)(ii) I50.36(c)(2) I50.73(a)(2)(vii) IOTHER (Specify in 1 0 I20.405(a)(1)(iii) I50.73(a)(2)(i)(B)I I50.73(a)(2)(viii)(A) Abstract below and in I20.405(a)( 1)(iv) XI50.73(a)(2)(.ii) I I50.73(a)(2)(viii).(B) Text, NRC Form 366A) 20.405 a 1 v I

50.73 a 2 iii 50.73 a 2 x LICENSEE CONTACT FOR THI LER 12 NAME TELEPHONE NUMBER I AREA CODE I S. W. Austin 2 7 2 9 -- 2 0 7 COMPLETE ONE LINE F R EACH COMPONENT FAIL RE DE CRIBED IN THIS REPORT 1 I I I IREPORTABLEI I I I I IREPORTABLEI CAUSE SYSTEM COMPONENT MANUFACTURER T NPRDS CAUSE SYSTEM C MPONENT MAN FACTURER TO NPROS SUPPLEMENTAL REPORT EXPE TEO 14 EXPECTED IMONTH DAY YEAR I I SUBMISSION I I I X YES If es com 1 etc EXPECTED SUBMISSION DATE NO DATE 15 0 6 2 7 '9 3 ABSTRACT (Limit to 1400 spaces, i.e., approximately fifteen single-space typewritten lines) (16)

On January 31, 1993, at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br /> during performance of'ocal leak rate testing, it was determined that the main steam system isolation valves (MSIV) on main steam line "C" were found to have leakage in excess of the technical specification limit of 11.5 standard cubic feet per hour (SCFH).

The root cause of thi's event has not been identified. A preliminary investigation into the cause has concluded that the inboard MSIV may be leaking more than the allowed 11.5 SCFH.

Corrective'ctions will be to determine which MSIV is leaking, repair the valve, and retest this valve. TVA will issue a followup report detailing the corrective actions.

NRC Form 366(6-89)

0 0 NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION Approved OMB No. 3150-0104 (6-89) Expires 4/30/92 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1) IDOCKET NUMBER (2) LER NUMBER PAGE 3

• I I' SEQUENTIAL I IREVISIONI I I I I I

Browns Ferry Unit 2 YEAR NUMBER NUMBER I' I

05 00 2 6 0 3 0 2 --'0 0 I

2 OF 5 TEXT (If more space is required, use additional NRC Form 366A's) (17)

I. PLANT .COHDITIOHS Unit 2 was in cold shutdown for the Unit 2 cycle 6 refueling outage. Units 1 and 3 .were defueled.

.II. DESCRIPTIOH OF EVEHT A. Event:

On January 31, 1993, at 1030 hours0.0119 days <br />0.286 hours <br />0.0017 weeks <br />3.91915e-4 months <br /> during performance of local leak rate testing, it was determined that the main steam [SB] system isolation valves (ISV), on main steam line "C" were found to have leakage in excess of the technical specifications (TS) limit of 11.5 standard cubic feet per hour (SCFH) allowed for a main -steam isolation valve (MSIV). Furthermore the leak rate of the valve exceed'ed the 655.9 SCFH allowed for total primary conta'inment. The leak rate in steamline "C" was determined to be 1320.26 SCFH.

TVA reports this in accordance with 10 CFR 50.73 (a)(2)(ii)(A) as any event or condition that resulted in the condition of the nuclear plant, including its principal safety barriers, being seriously degraded or that resulted in the nuclear plant being in an unanalyzed condition that

. significantly compromised plant safety.

B. Ino erable Structures Com onents or S stems that Contributed to the Event:

None.

C. Dates and A roximate Times of Ma or Occurrences:

January 31, 1993, at 1030 Primary containment total leak CST rate is determined to have exceeded acceptance criteria.

January 31, 1993, at 1420 TVA makes a four-hour CST nonemergency notification to NRC in accordance with 1'0 CFR 50 72(b)(2)(i)

NRC Form 366(6-89)

Cl 0 NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION Approved OMB No. 3150-0104 (6-89) Expires 4/30/92

,LICENSEE EVENT REPORT (LER)

TEXT .CONTINUATION FACILITY NAME (1) IOOCKET NUMBER (2) LER N MBER 6 PAE 3

=I I I I SEQUENTIAL I

~

!REVISION! I I I I Browns Ferry Unit 2 I YEAR N MBER N MBER I I I I 5 0 0 2 6 2 I F TEXT (If more space is required, use additional NRC Form 366A's) (17)

D. Other S stems or Seconda Functions Affected:

None.

E. Method of Discove The leak rate was determined to be unacceptable during performance of the surveillance instruction that determined the amount of leakage through main steam line "C" primary containment isolation valves.

F. 0 erator Actions:

None.

G. Safet S stem Res onses:

None.

III. CAUSE OF THE EVENT'.

Immediate Cause:

The immediate cause of this event was leakage of one or both of the MSIVs leaking an amount greater than the TS limit.

B. Root Cause:

The root cause of this event has not been identified. A preliminary investigation into the cause indicates that the inboard main steam isolation valve may be leaking. However, TVA will not know the root cause until after the inboard and outboard isolation valves have been inspected.

C. Contributin Factors:

None.

NRC Form 366(6-89)

4I 0 NRC Form 366A U.S. NUCLEAR REGULATORY COMMISSION Approved OMB No. 3150-0104 (6-89) Expires 4/30/92 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAME (1) IDOCKET NUMBER (2) LER NUMBER PAGE 3 I I I ISEQUENTIAL I IREVISIONJ (,I I I

Browns Ferry Unit 2 YEAR N MBER NUMBER I I I I I

2 6 0 0 .2 0 0 0 4 F TEXT (If more space is required, -use additional NRC Form 366A's) '(17)

IV. AHALTSIS OF THE EVENT Each main steam line has two isolation valves, one on the inside and one on the'outside of primary containment. The isolation valves prevent radiation release in excess of 10 CFR 100 guidelines in the event of a steam line break outside primary containment. The valves also limit inventory loss during a loss of coolant accident. Technical specificat,ions require that the MSIVs be tested for leakage during each refueling outage., If the leakage rate for any one MSIV exceeds 11.5 SCFH, TS require that the valve be repaired and retested to correct the condition. TVA will determine which valve is leaking, repair the valve, and retest it.

V. CORRECTIVE ACTIONS A. Immediate Corrective Actions:

None.

B. Corrective Actions to Prevent Recurrence:

1. TVA will determine which MSIV is leaking, repair the valve, and retest this valve.

2. TVA will issue a followup report detailing the corrective actions.

VI. ADDITIOHAL IHFORMATIOH A. Failed Com onents:

None.

B. Previous LERs on Similar Events:

TVA has previously issued reports detailing multiple failures of MSIVs to meet the required acceptance criteria. Subsequently, TVA has instituted a MSIV upgrade program. This program has greatly reduced the number of failures. Therefore, TVA concludes the corrective action was adequate to minimize recurrence.

NRC form 366(6-89)

41 NRC Form 366A U.S. NUCLEAR REGUL'ATORY COHHISSION Approved OHB No. 3150-0104 (6-89) Expires 4/30/92 LICENSEE EVENT REPORT (LER)

TEXT CONTINUATION FACILITY NAHE (1) iDOCKET NUHBER '(2) - LER NUHBER 6 PAE 3 I

I I I SEQUENTIAL i iREVISIONl I I I I Browns Ferry Uni t 2 I YEAR NUHBER N HBER 0 2 6 0 3 2 F TEXT (If more space is required, use additional NRC Form 366A's) (17)

VII ..COMMITMHHTS

1. TVA will determine which MSIV is leaking, repair the valve, and retest it. This will be accomplished prior to restart from the Unit 2 cycle 6 outage.

2. TVA will issue a followup report detailing corrective action. The report will be issued 30 days, after completion of the Unit 2 cycle 6 refueling outage.

Energy Industry Identification System (EIIS) codes are identified in the text as [XX] .

NRC Form 366(6-89)

II I