ML17262A627

From kanterella
Jump to navigation Jump to search
Ro:On 911011,pin Hole Leak in 1/2-inch Copper Tubes Between 3-inch Carbon Steel Discharge Header & Cooling Coils on Fan Cooler B Discovered.Caused by Defect in Tubes.Work Request/ Trouble Rept Initiated.Reported Per NRC Bulletin 80-24
ML17262A627
Person / Time
Site: Ginna Constellation icon.png
Issue date: 10/24/1991
From: Mecredy R
ROCHESTER GAS & ELECTRIC CORP.
To:
NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
IEB-80-24, NUDOCS 9111040275
Download: ML17262A627 (8)


Text

ACCELERATED jgjSTRIBUTION DEMON+RATION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9111040275 DOC.DATE: 91/10/24 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G

05000244 AUTH.NAME AUTHOR AFFILIATION MECREDY,R.C.

Rochester Gas

& Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION Document Control Branch (Document Control Desk)

SUBJECT:

RO:on 911011,pin hole leak in 1/2-inch copper tubes between 3-inch carbon steel discharge header

& cooling coils on fan cooler B discovered. Caused by defect in tubes. Work request/

trouble rept initiated. Reported per NRC Bulletin 80-024.

DISTRIBUTION CODE:

IE22D COPIES RECEIVED:LTR I ENCL

(

SIZE: 5 TITLE: 50.73/50.9 Licensee Event Report (LER), -Incident Rpt, etc.

D

  • S NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72).

05000244 p

RECIPIENT ID CODE/NAME PD1-3 LA JOHNSON,A INTERNAL: ACNW AEOD/DSP/TPAB NRR/DET/ECMB 9H NRR/DLPQ/LHFB10 NRR/DOEA/OEAB NRR/DST/SELB 8D

~yQ3gg/SPLB8D1

~G~ZE 02 RGN1 FILE 01 EXTERNAL: EG&G BRYCE,J.H NRC PDR NSIC POORE,W.

'COPIES LTTR ENCL 1

1 1

1

.2 2

1 1

1 1

1.

1 1

1 1

1 1

1 1

1 1

1 3

3 1

1 1

1 RECIPIENT ID CODE/NAME PD1-3 PD AEOD/DOA AEOD/ROAB/DSP NRR/DET/EMEB 7E NRR/DLPQ/LPEB10 NRR/DREP/PRPB11

'NRR/DST/SICB8H3 NRR/DST/SRXB 8E RES/DSIR/EIB I'

ST LOBBY WARD NSIC MURPHY,G.A NUDOCS FULL TXT COPIES LTTR ENCL 1

1 1

1 2

2, 1

.1' 2

2 1

1 1

1 1

1 1

=

1 1

1 1

1 D

D g') g. Ct'5'f < <5 D

NOTE TO ALL"RIDS" RECIPIENTS:

D D

PLEASE HELP VS TO REDUCE WASTE! CONTACT THE DOCUMENT CONTROL DESK, ROOivI Pl-37 (EXT. 20079) TO ELIMINATEYOUR NAiVIEFROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED:

LTTR 3 1 ENCL 3 1

ROCHESTER GAS AND ELECTRIC CORPORATION t j i.> -

tone

/>>

St Alc o, 89 EAST AVENUE, ROCHESTER N.K 14649-0001 ROBERT C PrtECREDY Vi<<o Prnsidont Cinnn ttucfear Production TELEPHONE AREACODE 7$ 6 546 2700 October.24, 1991 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

Subject:

Service Water. Leak Inside Containment R.E.

Ginna Nuclear Power Plant Docket No. 50-244 In accordance with the requirements of IE Bulletin No. 80-24, (Prevention of Damage Due to Water Leakage Inside Containment),

the attached 14 Day Report is hereby submitted.

Very 'truly yours, xco U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna USNRC Senior Resident Inspector

~olll04027S allo;I4 PDR AQOCK 05000244 PDfi

SERVICE WATER LEAK INSIDE CONTAINl69FZ PRE-1909FV CONDIT1ONS I

The plant was at approximately 974 steady. state reactor power.

During the 0000-0800 shift on October 11, 1991,-

the Control Room operators noted that the "B" Containment (CNMT) Recirc Fan Cooler Condensate Collector Level began increasing with the fan unit secured.

Calculations indicated that the level, increase was equal to a leakrate of approximately

. 0.02 gallons per minute (GPM).

The Control Room operators suspected that the level increase was due to a service water leak in a cooling coil in the "B" CNMT Recirc Fan.

On October 11, 1991 at 0822 EDST, the "B"

CNMT Recirc Fan was declared inoperable and service water to the unit was isolated.

DESCRIPT1ON OF EVENT On October 11, 1991 at approximately 1400 EDST, with'he reactor.at approximately 97% full power, a

containment.

entry was made by Maintenance Personnel to perform a

visual leakage inspection of the "B"

CNMT Recirc Fan Cooler System.

The service water inlet valve to the "B" CNMT Recirc Fan Cooler was slightly opened to allow personnel to visually inspect for the leak.

The inspection reveale'd a pinhole leak in one of the nominal one half (1/2) inch copper tubes between the three (3) inch carbon steel discharge header and the cooling coils on the "B"

CNMT Recirc Fan Cooler.

Ultrasonic thickness checks of the

tube, performed on October 11,
1991, indicated that the pinhole was an isolated defect and not representative of an eroded condition in the tube.

The cooler was isolated and held and a

Ginha Station Work Request or Trouble Report (WR/TR) was initiated (i.e., WR/TR,g9101754) to repair the service water, leak associated with. the "B" CNMT Recirc Fan Cooler.

The Control Room operators notified higher supervision, the Nuclear Regulatory Commission (NRC),

and the NRC Resident Inspector of the event.

CORRECTIVE ACTION A.

ACTION TAKEN TO RE'IXJRN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:

Work Order Package g9101754 was prepared to repair the tube defect using a silver soldered overlay copper patch.

Emergency Maintenance Procedure EM-745 (Repair of "B" Containment Fan Cooling Coils), in'on)unction with the work order requirements, controlled the repair activity, performed on October 13, 1991.

Upon completion of the

repair,

. a ten minute leakage examination at operating pressure was performed to ensure adequacy of the repair and the integrity of the "B" CNMT Recirc Fan Cooling Coils.

ACTION TAKEN OR PLANNED'TO PREVENT RECURRENCE:

As the underlying cause of the event was determined to be an isolated

defect, no immediate corrective action to prevent recurrence is planned at this time.
However, during the 1992 Annual Refueling and Maintenance
Outage, additional investigations will be scheduled to assess the condition of the coolers.

An assessment of other

coolers, used to control containment fan motor temperatures, has shown them.to be in a

degraded condition and these motor coolers are planned for replacement in 1992 (Ref:

14 Day Report dated September 17, 1991).

The fan.coolers are of. similar vintage and are being considered for replacement starting in 1994.

l