ML19331C725

Final Deficiency Rept Re Environ Qualification of Cutler- Hammer Type 10250T Switches for Use in Class IE Circuits. Cause Not Stated.Switches Will Be Deleted Prior to Startup & Substituted W/Main Control Room Switches

ML19331C725
Person / Time
Site:	Sequoyah
Issue date:	08/12/1980
From:	TENNESSEE VALLEY AUTHORITY
To:
References
NCR-SQN-EEB-800, NUDOCS 8008190444
Download: ML19331C725 (3)

Text

h TENNESSEE VALLEY AUTHORITY CHATTANOOGA. TENNISSEE 374c 6 400 Chestnut Street Tcwer II August 12, 1960 N~

Mr. James P. O'? .11y, Director Office of Incpecticn and Enforcement U.S Nrcle d Regulatory Cc missicn Resic,n I~ - Suite 3100 101 l'.n letta Street Atic a, Georgia 30303

Dear Mr. O'Reilly:

SEGUCYAH :.UCLEAR PLAllT UNIT 2 - SELEC"'OR SWITCHES ENVIRONME ITAL GUALIFICAT:Cli - NCR SQN EEB 8008 - FII;AL REPORT Ihe subject deficiency was initially reported to !!RC-0IE Inspector S. Thomas en June 6, 1980, in accordance trith 10 CFR 50.55(e). An

• interim report ma cubmitted cn July 7,1960. Encleced is cur final repCrt.

If you iwre any questiens ccncerning this matter, plerse get in touch with D. L. La=dert at FTS 857-2581.

Very truly yours, IEMIESSEE VALLEY AUTHORITY L. M. Mills, Manager Nuclear Regulaticn and Safoty Encicsure cc: :.r.Victer Stello, Jr., Director (Enclosure)

Office of Inspecticn and Enforcement U.S. Nuclear Regulatory Cc=miscien Washingten, DC 20555 k

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• ENCLOSURE SEQUOYAH NUCLEAR PLANT UNIT 2 SELECTOR SWITCHES ENVIRONMENTAL QUALIFICATION NCR SQN EEB 8008 10 CFR 50.55(e)

FIRST INTERIM REPORT Description of Deficiency Cutler-Ha==er switches type 10250T are used in Class IE control circuits for safety related equipment. The switches are mounted locally to the equipment and are used in testing such that equipment operability can be directly observed. The switches .

are wired in the circuits with other switches in the main control room which are used to control the equipment manually or -

autcmatically.

During a review of the switch contract documents, it was found -

that documentation is not on file to substantiate that these switches are environ =entally qualified to withstand the temperatures which could result from certain high energy line breaks.

Switches are located in local control boxes at each of the following locations:

(number of switthes per unit is in parentheses)

1. Vertical Pipe Chase at elevations 653, 690, 699 and 714 (19)

2. Auxiliary Feedwater Pump Turbine Room at elevation 669 (9) -

3. RHR Heat Exchanger Rooms at elevation 690 (2, one per room)

4. RER Pu=p Rooms at elevation 653 (6, three per room)

Safety Implications The failure of several of these switches during a high energy line break event could result in loss of control for the associated equipment. This could result in the multiple failure of safety functions claimed in the plant safety analysis, jeopardizing the safe operation of the plant.

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Corrective Actions An evaluation of all the handswitches covered by this NCR has shown that only two switches for unit 2 present a hazard to safe operation of the unit. These are switches No. 2-HS-72-40 and No. 2-HS-72-41 in the pipe chase.

It has been determined that these switches can be deleted and that the related switches in the main control room can be used in conjunction with a communications line to an observer near the valves for testing. The switches in unit 2 will be deleted before startup of unit 2.

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