ML17263A429

Special Rept:On 930930,operators Conservatively Declared Containment Isolation Valves Inoperable.Containment Recirculation Fans Replaced During 1993 Outage & Motor Coolers for Containment Recirculation Fans Replaced

ML17263A429
Person / Time
Site:	Ginna
Issue date:	10/14/1993
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	Andrea Johnson NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM), Office of Nuclear Reactor Regulation
References
NUDOCS 9310250098
Download: ML17263A429 (7)

Text

ACCELERAT]O DOCUMENT DISTKQfJTION SYSTEM REGULATORY INFORMATION DISTRIBUTION SYSTEM (RIDS)

ACCESSION NBR:9310250098 DOC.DATE: 93/10/14 NOTARIZED: NO DOCKET FACIL:50-244 Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH. NAME AUTHOR AFFXLIATION MECREDY,R.C. Rochester Gas & Electric Corp.

RECIP.NAME RECIPIENT AFFILIATION JOHNSON,A.R. Project Directorate I-3

SUBJECT:

Special rept:on 930930,operators ".conservatively declared" containment isolation valves inoperable. Containment recirculation fans replaced during 1993 outage 6 motor coolers for containment recirculation fans replaced.

DISTRIBUTION CODE: IE22D COPIES RECEIVED:LTR J ENCL TITLE: 50.73/50.9 Licensee Event Report (LER), Incident Rpt, etc.

g SIZE:

NOTES:License Exp date in accordance with 10CFR2,2.109(9/19/72). 05000244 RECIPIENT COPIES RECIPIENT COPIES ID CODE/NAME LTTR ENCL ID CODE/NAME LTTR ENCL PD1-3 LA 1 1 PD1-3 PD 1 1 JOHNSON,A 1 1 INTERNAL: AEOD/DOA 1 1 AEOD/DSP/TPAB 1 1 AEOD/ROAB/DSP 2 2 NRR/DE/EELB 1 1 NRR/DE/EMEB 1 1 NRR/DORS/OEAB 1 1 NRR/DRCH/HHFB 1 1 NRR/DRCH/HICB 1 1 NRR/DRCH/HOLB 1 1 ' NRR/DRIL/RPEB 1 1 NRR/DRSS/PRPB 2 SPLB 1 1 NRR/DSSA/SRXB 1 1 EG FIL 02 1 1 RES/DSIR/EIB 1 1 RGN1 FILE 01 1 1 EXTERNAI: EGGG BRYCE,J.H 2 2 L ST LOBBY WARD 1 1 NRC PDR 1 1 NSIC MURPHY,G.A 1 1 NSIC POORE,W. 1 1 NUDOCS FULL TXT 1 1 NOTE TO ALL"RIDS" RECIPIENTS:

PLEASE HELP US TO REDUCE WASTEI CONTACT THE DOCUMENT CONTROL DESK, ROOM Pl-37 (EXT. 504-2065) TO ELIMINATEYOUR NAME FROM DISTRIBUTION LISTS FOR DOCUMENTS YOU DON'T NEED!

TOTAL NUMBER OF COPIES REQUIRED: LTTR 28 ENCL 28

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i ROCHESTER GAS AND ELECTRIC CORPORATION e 89 EAST AVENUE, ROCHESTER N. Y, 14649-0001 ROBERT C, MECREDY TE EssssQNE Vice President Astcn cove P tc 546-2700 Cinne rcucfeer production October 14, 1993 U.S. Nuclear Regulatory Control Desk Commission'ocument Attn: Allen R. Johnson Project Directorate I-3 Washington, D.C. 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, Robert C. Mecr dy xc: U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 Ginna. USNRC Senior Resident Inspector 93i0250098 S'3i0i4 >zing PDR ADOCK 05000244 PDR ir

14 Da Re ort ofOService

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Water Leak Inside Containment PRE-EVENT PLANT CONDITIONS On September 30, 1993, the plant was at approximately 974 steady state reactor power. Maintenance had been initiated to repair a minor service water leak (estimated to be about

.25 GPM, which is below the administrative leakage limit for containment integrity) on the "A" Reactor Compartment Cooling Fan cooling coils. As part of the maintenance activities, the cooling coils had been isolated by closure of valves 4757 and 4758, a drain had been opened to fully drain the cooling coils, and the tubing in the area of the minor leak was being cut in preparation for installation of a mechanical plug.

II. DESCRIPTION OF EVENT On September 30, 1993, at approximately 1320 hours0.0153 days <br />0.367 hours <br />0.00218 weeks <br />5.0226e-4 months <br /> EDST, after containment isolation valves 4757 and 4758 had been closed, the cooling coil drain on the "A" Reactor Compartment Cooling Fan cooling coils was opened and the tubing cut.

The service water leakage into containment increased above the administrative containment integrity limit of 1. 25 GPM for the cooling coil closed system, and did not decrease within a time period consistent with draining of the affected piping and cooling coils. Operators then conservatively declared containment isolation valves 4757 and 4758 inoperable. Manual valves 4624, 4625, and 4626 (in series with valves 4757 and 4758) were closed in accordance with Technical Specification 3.6.3 (at approximately 1432 hours0.0166 days <br />0.398 hours <br />0.00237 weeks <br />5.44876e-4 months <br /> EDST), terminating the service water leakage into containment.

The Control Room operators notified higher supervision, the Nuclear Regulatory Commission (NRC) and the NRC Senior Resident Inspector of the event.

The service water leakage was continuously monitored throughout the event, and at no time did the conditions which resulted in the issuance of IE Bulletin 80-24 exist (i.e., unknown and unmonitored service water leakage inside containment) .

III. CORRECTIVE ACTION A. ACTION TAKEN TO RETURN AFFECTED SYSTEMS TO PRE-EVENT NORMAL STATUS:

Work Order package 9301452 was developed to perform tube repair on the, "A" Reactor Compartment Cooling Fan cooling coils, in accordance with procedure M-37.137, "Installation of 1/2" Vibra-Proof Condenser Plugs", and Nonconformance Report (NCR)93-237. The U-bend area was found thinned and leaking. The U-bend was cut off and the tubes were plugged in accordance with the work package, procedure and NCR instructions.

After tube repairs were completed, Work Order package 9321334 was used to perform maintenance on containment isolation valves 4757 and 4758, in accordance with procedure M-37.132, "Replace Retainer Ring and Seat on Xomox Butterfly Valves". The valves were disassembled, inspected, valve internals cleaned, and valve seats and retainer rings were replaced. The closed position "stop" was also adjusted for valve 4757.

Work was performed on valve 4757, valve 4758, and the cooling coils only after entering the Limiting Condition for Operation for Technical Specification 3.6.3, and was completed within the allowable four hour time period.

The valves, cooling coils and tube repair were then pressurized and visually inspected for leakage. The results of the visual inspection were acceptable. The "A" Reactor Compartment Cooling Fan cooling coils were then returned to operable status.

The system was then aligned for periodic test RSSP-2.8, to verify valves 4757 and 4758 containment isolation capability. The test results were acceptable. The system was aligned and returned to service.

Periodic test RSSP-2.8 was also performed for Containment Isolation Valves 4635 and 4636 (for the "B" Reactor Compartment Cooling Fan cooling coils), to verify acceptable isolation capability. The exposed cooling coils for the "B" Reactor Compartment Cooling Fan were visually inspected for leakage during RSSP-2.8. No leakage was noted. The valves were also found to be acceptable. No further actions were needed for these valves or cooling coils.

ACTION TAKEN OR PLANNED TO PREVENT RECURRENCE:

The underlying cause of the event for containment isolation valve operability was determined to be failure of valve 4757 to fully close, due to foreign materials accumulating on the seat surface and the closed position "stop" not properly adjusted.

The underlying cause of the event for the <<A" Reactor Compartment Cooling Fan cooling coils was determined to be U-bend thinning. Based on analysis of previous failures of copper tubes in these cooling coils, and similar thinning identified in other parts of the Service Water system, it has been hypothesized that particulate erosion/corrosion effects, which are naturally occurring phenomena in raw water been occurring in these cooling coils for several systems,'ave years.

The following actions to prevent recurrence have been or will be taken:

0 The Containment Recirculation Fan cooling coils were replaced during the 1993 annual outage, with coils of a material more resistant to erosion/corrosion effects.

0 The motor coolers for the Containment Recirculation Fans were replaced during the 1992 annual outage.

Performance of these coolers has been satisfactory.

0 A schedule for replacement of the "A" and "B" Reactor Compartment Cooling Fan cooling coils is under evaluation.

0 The frequency of preventive maintenance activities for containment isolation valves 4757 and 4758 will be determined as part of the Reliability-Centered Maintenance program.