ML20197J754

Part 21 Rept 86-01 Re Limitorque Valve operator-motor Lead Insulation Exhibiting Brittlement.Motor Leads for Motor Actuators Will Be Replaced W/Properly Insulated Wire by 860801

ML20197J754
Person / Time
Site:	Trojan File:Portland General Electric icon.png
Issue date:	05/06/1986
From:	Withers B PORTLAND GENERAL ELECTRIC CO.
To:	Martin J NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION V)
References
REF-PT21-86, REF-PT21-86-156-000 86-01, 86-1, PT21-86-156, PT21-86-156-000, TAC-42502, NUDOCS 8605200161
Download: ML20197J754 (4)

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May 6, 1986 Trojan Nuclear Plant Docket 50-344 License NPF-1 Mr. John B. Martin Regional Administrator, Region V U.S. Nuclear Regulatory Commission 1450 Maria Lane, Suite 210 Walnut Creek CA 94596-5368

Dear Sir:

TROJAN NUCLEAR PLANT 10 CFR 21 Defect Report Valve Operator-Motor Lead Insulation The attached 10 CFR 21 Defect Report identifies a defect which we have evaluated to be reportable in accordance with 10 CFR 21 requirements. The defect results from an apparent deviation in the quality of the motor lead insulation in replacement motor actuators installed at Trojan during the 1985 refueling outage. The supplier of the motor actuators, Limitorque Corporation, has been contacted and has been made aware of the results of our 10 CFR 21 Evaluation.

Please direct any questions you may have regarding the technical issues to Manager, Nuclear Plant Engineering, Mr. R. L. Steele.

Sincerely, w/

Bart D. Withers Vice President Nuclear Attachment c: Director, Inspection and Enforcement U.S. Nuclear Regulatory Commission Washington DC 20555 Mr. Lynn Frank, Director State of Oregon 8605200161 860506 Department of Energy PDR ADOCK 05000344 s PDR l  !

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i 10 CFR 21 DEFECT REPORT Portland General Electric Company Report Number: 86-01 121 SW Salmon Street Report Date: May 6, 1986 Portland, Oregon 97204 TROJAN NUCLEAR PLANT Responsible Officer: Mr. B. D. Withers, Vice President Nuclear Date Responsible Office Received Information: May 6, 1986 Basic Component or Activity: Electric Actuator (Valve Operator)

Type: SKB-000; 2 ft-lbs 125 Volts DC, Nominal PGE Purchase Order N-29175 Limitorque Order No. 3M4515 Firm Supplyina Basic Component: Limitorque Corporation PO Box 11318 Lynchburg, Virginia 24506 Description of Defect and Substantial Safety Hazard That Could be Caused:

As reported in Trojan Licensee Event Report No. 50-344/86-01, following a Plant trip on February 8,1986, operation of the "A" train auxiliary feedwater (AFW) flow control valve (CV-3004D1) to the "D" steam genera-tor was interrupted. The power supply fuse to the valve motor operator blew because of a motor lead short circuit. As indicated in LER 86-01, the probable cause of the blown fuse was the breakdown of the internal motor lead insulation resulting in a short circuit path to the grounded case of the valve operator.

During further evaluation and inspection of the AFW flow control valve operators, the motor lead insulation has exhibited a brittle nature.

Movement of the leads during maintenance could cause cracks in the brittle insulation. The weakened insulation would then be subject to failure under the normal vibration and operating environment of the motor actuator.

The Limitorque Corporation was contacted regarding the brittle nature of the insulation. Limitorque provided PCE with a repair procedure (appli-cation of Ray-Chem heat shrink tubing over the existing leads) should additional failures be identified. Further discussions with Limitorque indicate that the brittle condition of the insulation may be a quality control problem with the subcontractor (H. K. Porter) that supplied the motors to Limitorque. Consequently, Limitorque has established a program for the repair of the valve actuators that were supplied to Trojan with the apparent insulation defect. PGE informed Limitorque that an evaluation under 10 CFR 21 would be performed.

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- r Page 2 The results of the 10 CFR 21 evaluation indicate that a substantial safety hazard could exist should the insulation breakdown prevent the closure of an AFW flow control valve. During a feedwater line break accident, the AFW flow to the affected feedwater line must be isolated.

This action assures that sufficient feedwater flow is delivered to the intact feedwater lines and steam generators. The inability of the operator to take action to close the valve within 10 minutes would defeat the safety function of the AFW System to deliver an adequate volume of feedwater to the intact steam generators.

Number and Location of Such Components in Use at the Trojan Nuclear Plant:

The Trojan design (Four-Loop Westinghouse Pressurized Water Reactor) uses a total of eight AFW flow control valves in two redundant and independent safety-related trains. The valves are located in the Main Steam Support Structure between the Turbine Building and the Containment Building.

This is the only application for this particular type of direct current (de), 125-volt, valve motor actuator at Trojan.

Corrective Action:

The motor leads for the motor actuators will be replaced with properly insulated wire as recommended by the Limitorque Corporation. Every effort will be made to complete this work prior to the conclusion of the refueling outage on June 11, 1986. A completion date of August 1, 1986 will be met in any case.

Other Pertinent Information:

The motor actuators with the apparent insulation problem were installed in the Trojan Nuclear Plant in accordance with Plant design change, RDC 84-104. The AFW flow control valve actuators were upgraded in order to meet the environmental qualification requirements for electrical equipment located in the Main Steam Support Structure. The modification was completed during the 1985 refueling outage. ,

l Attached for reference is a copy of the Certified Information Sheet from the Limitorque Corporation which provides specific details regarding the electric actuator.

This report represents both the initial and final written notification to the NRC of the 10 CFR 21 defect.

MHM/kal 0822W.586

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LIMITCREUE CORPORATIUN P.O. Box 11318, Lynchburg, VA 24506 CERTIFIED INFORMATION SHEET - ELECTRIC ACTUATOR Lirnitorque Order No. 3M4515 Customer Name Portland Oregon General Electric Co.

Customer P.O. No. S.O. No.

N-29175 a x 7.. ,. ,

Unit Type & Size SMB-000 Motor 2 Ft.Lbs. Sultable for Volts DC Phase Cycle 125 Volts 1900 RPM Approximate Amps Approximate Amps Approximate Full Load 1.6 Locked Rotor 15.9 H.P. .144 Unit Enclosure Weatherproof Submersible ( ft. Head for hrs.)

Explosionproof Class Group (s) Div. 3 Nuclear Outilne Drawing: 02-403-0245-2 au mns _ ) _ )

Wiring Diagram: 15-476-1340-3 c y -) ; y 20, n . 2 . i ,

Limit Switch Compartment Heater 120 volt 25 watt Motor Heater 120 voit 40 watt CX8000lXGN N100tNXW0%)HE26XX XXX X X X X ooh p Nud X O)#00008tXXXX XX XX XX XX XNtM XX X Mechanical Dial Position Indicator X sNplied supplied Spur or Bevel Gear Attachment shplied supplied Ratio Handwheel Diameter inches (if other than standard) with spinner Position A B supplied (Applies to Electric / Manual Combinations only)

Tagging and Remarks:

Inside Containment, Safety Related, Qualified per Limitorque Qualification Report #B0009 In accordance with the actuator qualification, motor "T" drains must be field installed in place of the two lowest motor drain plugs. Motor "T" drains are tagged and located in the Limit Switch Compartment on shipment from Limitorque.

l (1) Diazo Mylar ENCLOSED:

All drawings and information listed above are certified for construction. Please advise us at once should you require any changes or corrections, as we are proceeding to manufacture in accordance with the above information. _

Limitorque Certification Department Revision By Name ,.c _hh Date FEB 0 5 1985 Date ,_ .,

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