ML17263A331

Part 21 Rept Re CCW HXs Mfg by Atlas Industrial Mfg Co.As Result of Eddy Current Exam Performed During 1993 Refueling Outage,Tubes W/Measurable Defects at Tube Plate Locations That Exceeded 70% of Tube Wall Thickness Removed from Svc

ML17263A331
Person / Time
Site:	Ginna
Issue date:	07/20/1993
From:	Mecredy R ROCHESTER GAS & ELECTRIC CORP.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-93 NUDOCS 9307290197
Download: ML17263A331 (9)

Text

ACCEjLERAT. D DOCUINIKNT DISTR UTION SYSTEM

• REGULA' INFORMATION DISTRIBUTIO YSTEM (RIDS)

T ACCESSION,'tJHR:9307290197 DOC.DATE': 93/07/20 NOTARIZED: NO DOCKET FACIL:50-.$44. Robert Emmet Ginna Nuclear Plant, Unit 1, Rochester G 05000244 AUTH:IfAME'UTHORAFFILIATION MECREDY,R.C. Rochester Gas 6 Electric Corp.

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

SUBJECT:

Part 21 rept re CCW HXs mfg by Atlas Industrial Mfg Co.As result of eddy current exam performed during 1993 refueling outage, tubes w/measurable defects at tube plate locations that exceeded 70% of tube wall thickness removed from svc.

DZSTRIBDTZON CODE: ZEISD COPIES RECEIVED:LTR TITLE: Part 21 Rept (50 DKT)

I ENCL 2 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 PD 1 1 JOHNSON,A 1 1 INTERNAL:~0 ROAB 1 1 NRR/DRIL/RVIB 1 1

~EG FILE 01 1 1 RES/DSIR/EIB 1 1 RON 1 1 RGN2 1 1 RGN3 1 1 RGN4 1 1 RGNS 1 1 SECY/PDR 1 1 EXTERNAL: INPO RECORD CTR 1 1 NRC PDR 1 1 NSIC SILVER,E 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 15 ENCL 15

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1 iixwsjIjI IIIIIII Sr*re ROCHESTER GAS AND ELECTRIC CORPORATION o 89 EAST AVENUE, ROCHESTER N.Y. 14649-0001 ROBERT C. MECREDY TELEPHONE Vlcc Prerldent AREA CODE 71B 546 2700 Cinna Nuclear Producrion July 20, 1993 U.S. Nuclear Regulatory Commission Document Control Desk Washington, DC 20555

SUBJECT:

10CFR21 30 Day Report R.E. Ginna Nuclear Power Plant Docket No. 50-244 In accordance with 10CFR21, Reporting of Defects and Noncompliance, Section 21.21(c), which requires "written notification to the NRC" "on the identification of a defect or a failure to comply",

the attached 10CFR21 report is hereby submitted.

Very truly yours, Robert C. Mecredy xc: Regional Administrator U.S. Nuclear Regulatory Commission Region I 475 Allendale Road King of Prussia, PA 19406 U.S. NRC Ginna Senior Resident Inspector iBOCCO 9'307290% 97 930720 ADOCH 05000244

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10CFR21 30 DAY WRITTEN REPORT NAME AND ADDRESS OF THE INDIVIDUAL INFORMING THE COMMISSION:

NAME: Robert C. Mecredy Vice President Ginna Nuclear Production ADDRESS: Rochester Gas & Electric Corporation 89 East Avenue Rochester, New York 14649 IDENTIFICATION OF THE FACILITY'HE ACTIVITY'R THE BASIC COMPONENT SUPPLIED FOR SUCH FACILITY WHICH FAILS, TO COMPLY OR CONTAINS A DEFECT:

The basic component is the Component Cooling Water (CCW)

Heat Exchanger. These heat exchangers were installed as original plant equipment at the R.E. Ginna Nuclear Power Plant.

IDENTIFICATION OF THE FIRM CONSTRUCTING THE FACILITY OR SUPPLYING THE BASIC COMPONENT WHICH FAILS TO COMPLY OR CONTAINS A DEFECT:

The CCW heat exchangers were manufactured by:

Atlas Industrial Manufacturing Company 81 Somerset Place Clifton, New Jersey 07012 NATURE OF THE DEFECT OR FAILURE TO COMPLY AND THE SAFETY HAZARD WHICH IS CREATED OR COULD BE CREATED BY SUCH DEFECT OR FAILURE TO COMPLY:

The purpose of this notification is to advise the industry of a condition that was not considered in the original design of this component. While this condition was not considered in the original design specifications, it does present a potential mechanism that could occur with heat exchangers supplied under design criteria prevalent with the vintage of this component.

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The defect identified in the design of the Component Cooling Water (CCW) Heat Exchangers was the potential for through wall tube failures to occur while operating at the heat exchanger's rated design conditions. A review of the CCW Heat Exchanger design using current heat exchanger design criteria indicated that, at the design shell side flow, the CCW Heat Exchangers were susceptible to localized high shell side velocities for tubes in the immediate vicinity of the shell inlet and outlet nozzles. These high velocities could result in flow induced vibrations leading to tube thinning from fretting damage at tube support plate locations. These conclusions were confirmed by discussions with Atlas Industrial. Atlas Industrial recommended that the heat exchanger tubes be examined to check for the presence of fretting damage.

Although no CCW Heat Exchanger tube leaks had been experienced at Ginna, the potential for flow induced vibration damage coupled with the presence of a small number of fretting defects during a 1989 tube inspection and the vendor's recommendation caused RG&E to schedule an inspection of CCW Heat Exchanger tubes during the 1993 Refueling Outage. A full length eddy current examination was performed of tubes in the vicinity of the shell inlet and outlet nozzles. This examination confirmed the presence of tube thinning due to fretting at tube support plate locations for tubes in the immediate vicinity of the shell inlet nozzle. No tube thinning due to fretting was seen at tube support plate locations in the vicinity of the shell outlet nozzles.

Tube thinning due to fretting could, over time undetected, result in tube leaks and potentially in if complete tube severance at the fretting locations.

Tube leaks and/or severance could result in the CCW Heat Exchangers becoming inoperable when called upon to perform their safety function. Loss of CCW Heat Exchangers would directly affect the functionality of the Residual Heat Removal System resulting in a degrada-tion in the ability of the plant's safety related systems to meet their long term cooling requirements.

THE DATE ON WHICH THE INFORMATION OF SUCH DEFECT OR FAILURE TO COMPLY WAS OBTAINED:

The information was obtained on April 19, 1993, at the completion of the review of Eddy Current test data for the CCW heat exchangers.

IN THE CASE OF A BASIC COMPONENT WHICH CONTAINS A I I DEFECT OR FA LS TO COMPLY g THE NUMBER AND LO CAT ON OF ALL SUCH COMPONENTS IN USE AT ~ SUPPLI ED FOR J OR BEING SUPPLIED FOR GINNA STATION:

There are two CCW heat exchangers, permanently installed in the Auxiliary Building at Ginna Station.

THE CORRECTIVE ACTION WHICH HAS BEEN'S BEINGS OR WILL BE TAKEN; THE NAME OF THE INDIVIDUAL OR ORGANIZATION RESPONSIBLE FOR THE ACTION; AND THE LENGTH OF TIME THAT HAS BEEN OR WILL BE TAKEN TO COMPLETE THE ACTION:

t As a result of the eddy current examination performed during the 1993 Refueling Outage, RG&E removed from service all tubes with measurable defects at tube support plate locations that exceeded 704 of the tube wall thickness. All tubes that were removed from service in 1993 due to fretting defects were stabilized with a tube stake and then plugged. The number of tubes removed from service during the 1993 Refueling Outage due to tube defects was less than 24 of the total number of tubes in the CCW Heat Exchangers. The design heat removal requirements of the CCW Heat Exchangers are still satisfied with this number of tubes plugged, since the heat exchanger design included approximately 10% margin for tube plugging.

Due to the localized nature of the flow induced vibration concern, RG&E plans on performing periodic examinations of the tubes in the vicinity of the shell nozzles to monitor for fretting damage at tube support plate locations. All tubes with defects exceeding the plugging criteria will be stabilized and plugged. RG&E is responsible for determining the frequency of future periodic tube examinations. Additionally, RG&E is evaluating the feasibility of reducing the CCW Heat Exchanger shell side design flow to decrease the potential for localized flow induced vibration damage to tubes.

ANY ADVICE RELATED TO THE DEFECT OR FAILURE TO COMPLY ABOUT THE FACILITY, ACTIVITY, OR BASIC COMPONENT THAT HAS BEEN'S BEINGS OR WILL BE GIVEN TO PURCHASERS OR LICENSES:

The present CCW Heat Exchangers were designed and built in the late 1960's prior to the development of existing criteria for heat exchanger design to preclude flow induced vibration concerns.. Heat exchanger designs from this period may be susceptible to flow induced vibration damage depending upon the design philosophy used by individual manufacturers. Either review of the original design against today's standards or periodic examination of tubes for flow induced vibration concerns would provide an indication that unexpected damage to tubes is occurring due to flow induced vibrations.

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