ML19351A406

Special Rept SR-89-002-00:on 890930,video Scan of Steam Generator 1 Tubesheet Indicated Presence of Foreign Object Lodged in Tube.Object Identified as Calibr Tube Pressure Cap.Caused by Inadequate Corrective Action

ML19351A406
Person / Time
Site:	Waterford
Issue date:	10/16/1989
From:	Mcgaha J LOUISIANA POWER & LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
SR-89-002-00, SR-89-2, W3A89-0188, W3A89-188, NUDOCS 8910200217
Download: ML19351A406 (4)

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h. -I? LOU 18tANA P O W E R & L 1 G H T[ WATERFORD 3 SES

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f October 16, 1989 L

i-U.S. Nuclear Regulatory Commission '

ATTENTION: Document Control Desk Washington, D.C. 20555

SUBJECT:

Waterford 3 SES Docket No. 50-382 License No. NPF-38 Reportina of Special Report r

Attached is Special Report Number SR-89-002-00 for Waterford Steam Electric Station Unit 3. This Special Report is submitted per ,

Regulatory Guide 1.133.

Very'truly yours,

.R. McGaha lant Manager 'Quelear JRM/KTWark Attachment .

cc: Messrs. R.D. Martin '

J.T. Wheelock - INPO Records, Center l' E.L. Blake ll W.M. Stevenson

'D.L. Wigginton 1 NRC Resident Inspectors l

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SPECIAL REPORT F

F SR-89-002-00 t ,

1 l IN-CORE INSTRUMENTATION PRESSURE CAP DISCOVERED IN #1 STEAM GENERATOR INTRODUCTION I At 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on September 30, 1989, Waterford Steam Electric Station Unit 3  !

was in cold shutdown when a video scan of the Steam Generator (SG) #1 tubesheet indicated the presence of a foreign object lodged in the tube opening at row 2 l

line 172. The foreign object was removed and positively identified as a movable in-core instrumentation (ICI) calibration tube pressure cap.

The ICI cap entered the Reactor Coolant S; stem (RCS) during refueling activities i e +

in April, 1988. The missing pressure cap was identified by Westinghouse  ;

refueling personnel, but attempts to recover the cap were unsuccessful, i Discussion with the refueling supervisor revealed that at che time, Westinghouse' t personnel felt confident that-tbc cap had been flushed out of the reactor control element assembly upper guide structure (UGS) and into the deep end of the refueling canal. ICI removal and disposal operations were being conducted in the deep end of the refueling canal, making a visual verification impractical.  ;

Because of the size of the cap (1.125 inches by 0.75 inches, 1.54 ounces) the Vibration and Loose Parts Monitoring System (VLPMS) diu not detect the  ;

presence of the dust cap in the RCS.

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The refueling team has examined their records and have determined that no other itecs were unaccounted for during the last refueling period. They have also l been instructed to notify the Waterford 3 Refueling Director of any future ,

occurrences relating to loose parts in the RCS. The presence of the pressure i cap had no measurable effect on SG heat transfer capability. Because the cap caused no damage to the SG tubesheet and did not affect core thermal performance, this event did not threaten the health and safety of the general public or

-plant personnel.

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• NARRATIVE k.

At 0400 hours0.00463 days <br />0.111 hours <br />6.613757e-4 weeks <br />1.522e-4 months <br /> on September 30, 1989, Waterford Steam Electric Station Unit 3 was in cold shutdown when a video scan of the Steam Generator (SG) #1 tubesheet indicated the presence of a foreign object lodged in the tube opening at row 2, line 172. The foreign object was removed and positively identified as a movable in-core instrumentation (ICI) calibration tube pressure cap. This report is submitted pursuant to Regulatory Guide 1.133.

The ICI pressure cap entered the Reactor Coolant System (RCS) during refueling activities in April, 1988. Refueling logs indicate that on April 20, 1988, technicians attempted to recover two ICI pressure caps from the reactor vessel flange. One cap was recovered, but the other cap slid onto the control element assembly (CEA) upper guide structure (UGS). On May 9, 1988, technicians again attempted to retrieve the cap but it fell down onto the ICI lower plenum plate.

Later that night the cap could not be located, leading personnel to the conclusion that the cap had been flushed out of the UGS and tato the refueling canal.

This conclusion was communicated to the Waterford 3 refueling director.

Refueling activities concluded without further pursuit of the pressure cap.

The plant has operated since May 1988 with no indication of a loose part in the j RCS.

The Waterford 3 Vibration and Loose Part Monitoring System (VLPMS) conforms to the sensitivity reqinirements imposed by Regulatory Guide 1.133, Revision 1 (detection of metallic loonc parcs weighing as little as 0.25 lb with a l

kinetic energy of 0.5 ft-lb, within 3 ft of a sensor). Because the pressure cap is cylindrically shaped, measuring 1.125 inches in length and 0.75 inches  !

outer diameter with a mass of approximately 1.54 ounces, it is reasonable to l

, expect that the VLPMS would not have detected its presence in the RCS.

Additionally, the physical dimensions of the cap are such that complete entry ,

1 into a SG tube was prohibited as the inner diameter of a SG tube is a nominal  !

0.69 inches. At the time of discovery, the cap was wedged (less than finger tight) at the inlet to the hot leg side of the SG tube mentioned above.  :

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[ 'The pressure cap was recovered in its entirety. The internal spring loading L assembly was intact; therefore, there is no reason to believe that any cap internals.or wear products were carried to the reactor fuel area. An inspection of the tubesheet area did not indicate any material defects. The presence of the cap partially inhibited flow into the SG tube, but even complete blockage of the tube would not significantly diminish the heat transfer characteristics of the SG. Refueling records have been examined and a determination made that no other items entered the RCS.

The root cause of t.his event is inadequate corrective action. Refueling personnel did not place sufficient emphasis on recovery efforts, which resulted in a presumption (the cap was flushed into the refueling canal). becoming the final assessment of the problem. Recovery efforts were not adequately planned and implemented, resulting in cursory attempts to extract the pressure cap from the system. Contributing to this was a lack of specific tracking of components, such as ICI pressure caps or dust caps, located within the refueling cavity or UGS area.

This event has been discussed with refueling personnel currently on-site for refuel three. Refueling personnel will immediately notify the Waterford 3 refueling director of any situation which may have resulted in the introduction of a loose part in the RCS or any other interrelated system, and a formal recovery plan will be instituted. In addition to the foreign material. exclusion program ultilized to control entry of material into the refueling area, refueling procedures have been changed to specifically log and track ICI pressure capo and ICI dust caps.

l Because core thermal performance was not affected and the presence of the  ;

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! pressure cap caused no identifiable material damage to the SG tubesheet or 1

associated tube, this event did not threaten the health and safet.y of the general public or plant personnel, j

PLANT CONTACT R.S. Starkey, Operations Superintendent, 504/464-3134.

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