ML16162A277

LER 79-004/03L-0 on 790615:RCS Leakage Observed & Unit Shut Down for Repairs.Caused by Leak on Packing on Pressurizer Spray Control Bypass Valve.Valve Was Backseated & Leakage Terminated

ML16162A277
Person / Time
Site:	Oconee
Issue date:	07/13/1979
From:	Lewis S DUKE POWER CO.
To:	NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II)
Shared Package
ML16162A278	List: ML16162A277 ML19225A162
References
LER-79-004-03L-01, LER-79-4-3L-1, NUDOCS 7907180505
Download: ML16162A277 (4)

Text

REGULATORY TNFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:7907180505 DOC.DATE: 79/07/13 NOTARIZED: NO DOCKET #

FACIL:50-270 Oconee Nuclear Station, Unit 2, Duke Power Co. 05000270 AUTH.NAME AUTHOR AFFILIATION LEWIS,S.R. Duk e Power Co.

RECIP.NAME RECIPIENT AFFILIATION Region 2, Atlanta, Office of the Director

SUBJECT:

LER 79-004/03L-0 on 790615:RCS leakage observed & unit shut down for repairs.Caused by leak on packing on pressurizer spray control bypass valve.Valve was backseated &. leakage terminated.

DISTRIBUTION CODE: A002S COPIES RECEIVED:LTR / ENCL / SIZE: /f.

TITLE: INCIDENT REPORTS NOTES: /V?. CA/A//A//,qm - Am /VaA TO ripLL FS44 v C'R/4'EJ 7z TE'/

RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL ACTION: 05 BC Ci #-' 4 4 INTERNAL 1 1 02 NRC PDR 1 1 09.I&E 2 2 11 MPA 3 3 14 TA/EDO 1 1 15 NOVAK/KNIEL 1 1 16 EEB 1 1 17 AD FOR ENGR 1 1 18 PLANT SYS BR 1 1 19 I&C SYS BR 1 1 20 AD PLANT SYS 1 1 21 AD SYS/PROJ 1 1 22 REAC SAFT BR 1 1 23 ENGR BR 1 1 24 KREGER 1 1 25 PWR SYS BR 1 1 26 AD/SITE ANAL 1 1 27 OPERA LIC BR 1 1 28 ACDENT ANLYS 1 1 29 AUX SYS BR 1 1 E JORDAN/IE 1 1 HANAUERS. 1 1 TMI-H STREET I I EXTERNAL: 03 LPDR 1 1 04 NSIC 1 1 29 ACRS 16 16 TOTAL NUMBER OF COPIES REQUIRED: LTTR 48 ENCL 48

DUKE POWER GOT4iPANY POWER BUILDING 422 SouTHCHURCH STREET, GHARLOTTE, N. C. 28242 WILLIAM 0. PARKERJR.

VICE PRESIDENT July 13, 1979 TELEPHONE:AREA 704 STEAM PRODUCTION 373-4083 Mr. James P. O'Reilly, Director U.S. Nuclear Regulatory Commission Region II 101 Marietta Street, Suite 3100 Atlanta, GA 30303 Re: Oconee Unit 2 Docket No. 50-270

Dear Mr. O'Reilly:

Please find attached Reportable Occurrence Report RO-270/79-4. This report is being submitted pursuant to Oconee Nuclear Station Technical Specifications 6.2 and 6.6.2.1.b(2), which concerns shutdown required by .a limiting condition for operation, and describes an incident which is considered to have no significance with respect to its effect on the health and safety of the public.

Very truly yours, William 0. Parker, Jr.

SRL/sch Attachment cc: Director, Office of Management Information and Program Control th Anniversary OWER 7 07180

DUKE POWER COMPANY Oconee Unit 2 Report Number: RO-270/79-4 Report Date: July 13, 1979 Occurrence Date: June 15, 1979 Facility: Oconee Unit 2, Seneca, South Carolina Identification of Occurrence:. Unidentified RCS Leakage in Excess of 1 GPM Conditions Prior to Occurrence: 100% Full Power Description of Occurrence:

At 12 10 on June 15, 1979, unidentified Reactor Coolant System (RCS) leakage of approximately 3 gpm was indicated by increases in the Reactor Building (RB) sump temperature and in the levels recorded by the RB particulate and iodine monitors. At 1530 the.Reactor Building was entered, and the probable source of the leakage was .determined to be valve 2RC-2, the pressurizer spray control bypass valve. An evaluation of the leakage was made, and it was determined that operation of the unit should be permitted to continue. Unit shutdown was initiated at 2400 on June 15 in order to allow reentry of the Reactor Building for further evaluation. On June 16, 1979, the source was verified to be packing leakage from valve .2RC-2. The valve was backseated, terminating the leakage, and the unit was subsequently restarted.

Apparent Cause. of Occurrence:

The RCS leakage was determined to be the result of packing leakoff from valve 2RC-2, the pressurizer spray control bypass valve.

Analysis of Occurrence:

Since the source of the RCS leakage could not be conclusively determined during power operation, actions were taken pursuant to Oconee Nuclear Station Technical Specification 3.1.6.2, which requires that the unit be shut down within 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> of detection. Immediate action is required to assure that the leak is not the result of a slight materials failure which might develop into a more serious situation. The source.of the leakage was identified to be the packing on valve 2RC-2. The 3 gpm leak rate was significantly less than the capacity for makeup flow, and the leaking coolant was completely contained within the Reactor.Building. In addition, operation of the unit is permitted with a leak rate of up to 10 gpm, provided that the source of the leakage has been identified. However, the leakage did result in shutdown of the unit required by a limiting condition for operation. The incident must therefore be reported pursuant to Technical Specification 6 .6.2 .1.b(2),-although it was of no significance with respect to safe operation of the unit, and the health and safety of the public were not affected.

790718'0

Corrective Action:

After a preliminary determination was made that the RCS leakage was due to a packing leak, the unit was shut down, and the source was identified to be the packing on valve 2RC-2. The valve was backseated, terminating the leakage.

Consideration will be given to repacking or replacing the valve at the next available outage.

NRC FORM 364 U. S. NUCLEAR REGULATORY COMMISSICN (7-77)

LICENSEE EVENT REPORT EXHIBIT A CCNTROL 3LOCK: (PLEASE PRINT OR TYPE ALL REQUIRED INFORMATION) m 0 1

7 8 9 IN1I EIE 212C UCENSgE COCE 14 is 0 01-1 0f 010 101 01 -1010 JCt4.f f111l1 1 1 OL)0

- LICENSE NUMdER :5 25 UCENSE 7YP .10 57 CAT 6a CONT ou L 60 1101 5 0015 t

10 101 21 71 CQCXET NUMBER 63 C

69 o0 61 1 11f 719 EVENT CATE 3jJ0 17 11131 71 9 74 75 AEPCAT DArE 80 EVENT DESCRIPTION AND PROBABLE CONSEQUENCES G 0 Unidentified RCS leakage of approximately 3 gpm was observed, and the unit Iwas shut down in order to effect repairs. The packing on the pressurizer S7 spray control bypass valve, valve 2RC-2, was determined to be the source.

F577 Since the leakage was contained by the Reactor B3uilding and since the leakage o6 Irate was well within makeup capabilities, safe operation of the unit was not 0affected, and the health and safety of the public were not endangered.

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ED Cuu.s.pu C IORI OECRiPTJI PC 41 42 43 47 10[The leakage was determined to be due to a packing leak on valve 2RC-2. The 1Ivalve was backseated. terminating the leakage. Consideration will be given to!

2Irepacking or replacing the valve at the next available outage.

FACILITY kf7)c Cot S7rTA54 POW~ER OITMERSTATU4 \ CISCZVIERY C13COVIERY OESCRIPTI1 1 I -J L if1 0[ f NA AJJ Operator observation 7 31 10 12 12 4 6 RELASED

[CIVT Z.7 00 RELEASE ACTVIYSONEL M

() AMOUNT N OF C-NFIrv NA LOCATION OF RELEAESCT ( sooues.e 7 8 o1 10 26

[l] oWo oJIm PERSONNEL EXPOSURES NUMSEP TYE DESCRI j NA PTION

[ ] ioool181 NA 7 8 . 11 12

• PRSCNNEfL INJURIES 8 NUMBeR OESCRItr1cN lo0foolI Lp- NA 7 a1 9i 1 LOSS OI OR CAMAGE TO FACILITY 80 TYPE DESCRITION .

NA 7 *89 10 PUBLICITY SO ISSUED DESCRIPION NAC USE ONLY 20 Uje. o NA 8~~~6 1aosLj NAME OF PREPARFR S. R. Lewis PCNE: (704) 373-8285