ML20058K643

Part 21 Rept Re Potential for Unacceptable Recirculation Spray Sys Operation for Supporting Long Term Core Cooling Capability.Caused by Disc of motor-operated Valve on Suction of Pump Not Engaged to Motor Operator

ML20058K643
Person / Time
Site:	Beaver Valley
Issue date:	12/10/1993
From:	Freeland L DUQUESNE LIGHT CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
REF-PT21-93 ND3MNO:3519, NUDOCS 9312150346
Download: ML20058K643 (8)

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Duquesne Udit .... _ _ _  ;

N.Jclear Group -

P O Bow 4 i Shippmgport FA B077-000. ,

December 10,1993  :

ND3MNO:3519 l 5

Beaver Valley Power Station, Unit No. 2 l BV-2 Docket No. 50-412, License No. NPF-73 l Potential 10 CFR 21 Condition, Suction Valves for the Recirculation Spray Pumps ,

Snecial Reoort i

I U. S. Nuclear Regulatory Commission  ;

Document Control Desk j Washington, DC 20555 l Gentlemen:  !

i Duquesne Light Company hereby submits the attached report in accordance with the requirements of 10 CFR Part 21. This issue involves the potential for unacceptable -!

recirculation spray system operation for supporting long term core cooling capability ,

and maintaining containment pressure subatmospheric in the event of a loss-of-coolant- .

accident (LOCA).

l Should you have any further questions regarding this matter, please contact D. G. Mel.ain at (412) 393-4736. i i

! R. Freeland 140006 General Manager

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Nuclear Operations j i

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- 5 9312150346 931210  :.  :

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. . December 10,1993 ND3MNO:3519 Page 2 -l cc: Mr. T. T. Martin, Regional Administrator g United States Nuclear Regulatory Commission i Region 1  !

475 Allendale Road {

King of Pmssia, PA 19406  ;;

Mr. G. E. Edison, BVPS Licensing Project Manager United States nuclear Regulatory Commission  !

Washington, DC 20555 i I

Larry Rossbach, Nuclear Regulatory Conunission,  ;

BVPS Senior Resident inspector l

J. A. lioltz, Ohio Edison  :

76 S. Main Street Akron, Oli 44308 j i

Mark Burns  ;

Centerior Energy l 6200 Oak Tree Blvd.  !

Independence, Oli 44101-4661

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INPO Records Center .

700 Ga!!cria Parkway  !

Atlanta, GA 30339-5957  !

Mr. Robert Barkanic  :

Department of Environmental Resources l P.O. Box 2063  !

16th Floor, Fulton Building liarrisburg, PA 17120 i i

Director, Safety Evaluation & Control l Virginia Electric & Power Co.

P.O. Box 26666 One James River Plaza  ;

Richmond, VA 23261 .l r

t W. Ilarticy Virginia Power Company 5000 Dominion Blvd.

2SW Glenn Allen, VA 23060 ,

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l December 10,1993 ]

- ND3MNO:3519  ;

Page 3  !

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1 cc: 1. M. Riddle  ;

Halliburton NUS 1 Foster Plaza 7 '

661 Anderson Drive i Pittsburgh, PA 15220 ,

i Bill Wegner, Consultant  ;

23 Woodlawn Terrace Fredricksburg, VA 22405 l i

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ND3MNO:3519 {

Attachment 1 Page1-10 CFR Part 21 BVPS Unit No. 2 - Suction Valves for the Recirculation Spray Pumps -  ;

(i) Name and Address ofIndividual Making Notification:

i L. R. Freeland, General Manager, Nuclear Operations l Duquesne Light Company Beaver Valley Power Station P.O. Box 4 Shippingport, PA 15077 Basic Component Affected: f (ii)

Motor-operated suction valves [2RSS-MOVl55A, B, C and D] for the Recirculation Spray Pumps which are utilized for long term core cooling capability and maintaining the containment pressure subatmospheric in the event  ;

of a Loss of Coolant Accident (LOCA). The valve is a 12" Henry Pratt .

Butterfly Valve (Model 1400). l (iii) Firms Supplying Components:

Supplier: Henry Pratt Company l i

401 South Highland Ave.

Aurora, Illinois 60506-3392 (iv) Nature of Defect: y i

During shutdown mode testing of Recirculation Spray Pump [2RSS-P21D], the pump developed inadequate discharge pressure. Subsequent investigation discovered that the disc of the motor-operated valve (MOV) on the suction of the pump was not engaged to the motor operator. The shaft spline adapter of the motor-operator hi :noved out of position becoming separated from the adapter drive sleeve.

The spline adapter is retained in the motor operator by an adapter plate which is ,

in turn supported by a valve bonnet piece. The retention is accomplished by limiting the through-hole diameters of the adapter plate and bonnet piece to a value that would not allow the spline adapter to move out of position. Both diameters were intended to be the same for the above valve. If the adapter plate diameter is larger than the diameter of the bonnet piece, the spline adapter could be retained by the bonnet piece.

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' ND3MNO:3519  !

Attachment 1 Page 2 10 CFR Part 21 BVPS Unit No. 2 - Suction Valves for the Recirculation Sorav Pumps I (Continued) r However, this arrangement may not provide sufficient' spline engagement depending on specific valve dimensions (see attached sketch). For the Beaver -

Valley Power Station Unit Number 2, the adapter plate and bonnet piece-plate were provided by the valve manufacturer. The valve is a 12" Pratt Butterfly e valve (Model 1400) with a Limitorque HBC Operator.

This design deficiency was also noted on the other three Recirculation Spray  !

Pump Suction Valves for pumps 21 A, 21B and 21C. Therefore, common mode i failure of the suction valves for all four recirculation spray pumps potentially l existed if gone undetected. The deficiency was found during shutdown mode conditions. The investigation leading to the failure determined the suction valve >

[2RSS-MOV155D] failed either following the recent outage static MOV_ testing or during pump flow testing. This investigation confirmed the operability of the  ;

suction valves during power operation.

Duquesne Light Company (DLC) reviewed the original purchase order file, i i

applicable vendor documents, and the maintenance history, associated with the Henry Pratt valves (2RSS-MOV155A, B, C & D). DLC determined that there i was no work activity or initiating problem that could have led to modification or replacement of the adapter plate and/or bonnet at BVPS during construction or '

subsequent power operations and that the adapter plates are in their "as i received" condition. -

t Safety Implications:

If the failure had gone undetected, the possibility existed for a common mode failure of all four suction valves to the Recirculation Spray Pumps which would have prevented long term core cooling capability and containment cooling in the j' event of a LOCA. The suction valves are normally in the "open" position and will receive a signal to open on a Containment Isolation Phase "B" (CIB) to ensure the suction valve of the pump is open. However, the valves are stroke tested on a quarterly basis. The potential for the valve disc of the MO'/ to i l

become disengaged from the motor operator due to this common mode defect could have resulted in the valves becoming disengaged in the " closed" position.

The operations staff would not have had knowledge of this condition because the limit switches would have indicated "open" in the Control Room.

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l ND3MNO:3519 Attachment 1  :

Page 3 i

10 CFR Part 21 BVPS Unit No. 2 - Suction Valves for the Recirculation Spray Pumps (Continued)  !

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Also postulated was the failure of the recirculation spray pump 21D as a result i of the defect of the suction valve 2RSS-MOV155D (purple train powered) in .

conjunction with a single failure of the opposite train pump 21C (crange train l powered). When the low-low level setpoint of the Refueling Water Storage  ;

Tank is reached after Safety Injection initiation, the C and D Recirculation i Spray Pumps [2RSS-P21C, D] begin to support long-term core cooling by providing water from the Containment sump to the suction of the High-Head  ;

Safety Injection Pumps. Since the Recirculation Spray Pumps 21C and 21D are i the only two pumps capable of recycling water back to the Reactor Coolant i System, the injection phase via the Recirculation Spray System, in conjunction with single failure, could have been lost as a result of this defect.

Therefore, the defect, if gone undetected, could have created a major I degradation of essential safety related equipment, and a required safety system may not have performed its function. As such, the defect is reportable ,

pursuant to 10 CFR Part 21 requirements.

(v) Date On Which Defect Identified: ':

t The failure of the Recirculation Spray Pump Suction Valve [2RSS-MOV-155D]

was identified on October 17, 1993, during the regularly scheduled pump ,

performance test required by Tech Spec 4.6.2.2. The evaluation and resulting ,

report was presented to the On-Site Safety Committee on December 2,1993.

i (vi) Number and Location of Components:

Affected Components: BVPS Unit No. 2 Recirculation Spray l Pump Suction Valves  !

[2RSS-MOV155A, B, C and D]

Location: BVPS Unit No. 2 Safeguards Building f I

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Attachment 1 ,

Page 4 -:

i 10 CFR Part 21 1 BVPS Unit No. 2 - Suction Valves for the Recirculation Sprav Pumps i (Continued)

(vii) Corrective Actions Taken:

An inspection was conducted of the adapter plates and bonnets of all similar ,

valves supplied by Henry Pratt. It was concluded that the only valves affected by this defect are the four recirculation spray pump suction valves '

[2-RSS-MOV155A, B, C and D].

A temporary modification was made to the four suction valves which will  !

properly position and retain the spline adapter. A temporary clamp device has been secured to the valve shaft for all four valves to prevent axial movement of the spline adapter. The device has been tested and visually observed to confirm proper operation. Replacement adapter plates will be procured for the subject valves. Installation of the replacement hardware has been scheduled for the ,

next refueling outage (2R5). In the interim, the temporary modifications to the four valves will ensure proper operation.

(viii) Other Advice Related To Purchasers or Licensees:

None I

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