ML20003F411

Forwards Info Re Compliance w/NUREG-0737,Item II.F.2, Attachment 1, Design & Qualification Criteria for PWR Incore Thermocouples. Instrumentation Plans for Monitoring Inadequate Core Cooling Will Be Provided by 810630

ML20003F411
Person / Time
Site:	Sequoyah
Issue date:	04/13/1981
From:	Mills L TENNESSEE VALLEY AUTHORITY
To:	Schwencer A Office of Nuclear Reactor Regulation
References
RTR-NUREG-0737, RTR-NUREG-737, TASK-2.F.2, TASK-TM NUDOCS 8104210201
Download: ML20003F411 (3)

Text

TENNESSEE VALLEY AUTHORITY CH AT T ANOOG A. TENN ESS EE 37401 400 Chestnut Street Tower II April 13, 1981 Director of Nuclear Reactor Regulation Attention: Mr. A. Schwencer, Chief Licensing Branch No. 2 Division of Licensing U.S. Nuclear Regulatory Cossaission Washington, DC 20555

Dear Mr. Schwencer:

In the Matter of the Application of ) Docket Nos. 50-327 Tennessee Valley Authority ) 50-328 As requested by members of your staff, enclosed is information regarding the compliance of Sequoyah Nuclear Plant with NUREG-0737, Item II.F.2, Attachment 1, " Design and Qualification Criteria for PWR Incore Thermocouples." We expect to provide you with our dditiorJL1 plans for instrumentation for monitoring inadequate oore cooling by June 30, 1981.

If you have any questions, please get in touch with D. L. Lambert at FTS 857-2581.

Very truly yours, TENNESSEE VALLEY AUIHORITT

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L. M. Mills, Manager Nuclent Regulation and Safety Sworn to and subscr ed before me thig M day of if [ 1981 W 8 1.l k ,

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ENCLOSURE

.' , ,, SEQUOYAH NUCLEAR PLANT COMPLIANCE WITH NUREG-0737 ITEM II.F.2, ATTACHMENT 1 DESIGN A*D QUALIFICATION CRITERIA FOR PWR INCORE THERMOCOUPLES

1. We have 65 thermocouples, 60 of which are at the cor'. ' it plane and 5 of which are in the upper head region. Each r2 quadrant is adequately instrumented with thermocouples.

2. (a) The plant process computer can provide a spatially-oriented core map on demand indicating the temperatures across the area at each core exit thermocouple.

(b) Any core exit thermocouple can be put on digital or analog trend. The process computer software produces the average of

• all reliable thermocouples and the highest reading thermocouple ,

as an addressable. point which can be put on analog or digital trend.

(c) Hard-copy capability is available for all thermocouples from the process computer. The range extends from 0 F to the melting point of the thermocouples (N1770 F).

(d) As outlined above, trend capability exists for the core exit thermocouples.

(e) There are' appropriate alarms associated with the thermocouples provided in the control room.

(f) The process computer and Honeywell/ toggle switch displays for

• the thermocouples were designed and installed prior to human factor consideration requirements. __

(h) The process computer operator consoli is located in the

" horseshoe" of each control room. From the operator's console, the thermocouple output can be put on digital trend or multiple typers adjacent to the operator's console or on analog recorders on the control board.

3. The only backup display presently available for thermocouple output is the Honeywell/ toggle switch display. This device can be used to display all thermoccuple output, but only up to 700 F.

4. The types and locations of thermocouple displays and alarms were designed and installed prior to the requirement for human factor considerations. .

In TVA's response to the upcoming NUREG-0700, the whole control room will be evaluated from the standpoint of human factor considerations.

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.. . i ,+ 4 5, 6, 7, & 9. The thermocouple system was designed' and installed prior-to the implementation of Regulatory Guide 1.97 Revision 2; therefore, our system does not meet this regulatory guide.

{ 8. No availability data'is available on the Honeywell/ toggle switch

backup device but a 4-month availability test was run on the process computer which showed an availability in excess of 99 percent.

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