ML20137L777

Responds to 851010 Request to Modify Three Parameters in Design to Satisfy Requirements of Reg Guide 1.97 Per SER Open Item 6.Instrumentation Will Be Added to Indicate Current to Pressurizer Heaters

ML20137L777
Person / Time
Site:	Vogtle
Issue date:	01/21/1986
From:	Bailey J GEORGIA POWER CO.
To:	Youngblood B Office of Nuclear Reactor Regulation
References
RTR-REGGD-01.097, RTR-REGGD-1.097 X7BC35, NUDOCS 8601280083
Download: ML20137L777 (2)

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. Georg a Power Company

• Project Management Route 2 Box 299A Waynesboro. Georgia 30830 Telephone 404 724-8114 404 554-9 % 1 Southern Company Services. Inc.

Post Oftce Box 2625 L"%3M*"g, s Vogtle Project January 21, 1986 Director of Nuclear Reactor Regulation File: X7BC35 Attention: Mr. B. J. Youngblood Log: GN-784 PWR Project Directorate #4 Division of PWR Licensing A U. S. Nuclear Regulatory Commission Washington, D.C. 20555 NRC DOCKET NUMBERS 50-424 AND 50-425 CONSTRUCTION PERMIT NUMBERS CPPR-108 AND CPPR-109 V0GTLE ELECTRIC GENERATING PIANT - UNITS 1 AND 2 SER OPEN ITE1 6: REGULATORY GUIDE 1.97, Rev. 2

Dear Mr. Denton:

Safety Evaluation Report (SER) Open Item 6 addresses the VEGP position on RG 1.97, emergency response capability. In a telephone conversation on October 10, 1985, on this subject, the staff's reviewer requested that three parameters in the VEGP design be modified to satisfy the recommendations of the Regulatory Guide. In response to these requests, instrumentation will be added to indicate the current to the pressurizer heaters. This instrumentation will be added to the two diesel-backed, heater banks with indication available in the control room through the ERF computer.

Additionally, the instrumentation for pressurizer relief tank (PRT) temperature will be modified to increase the range f rom 50 - 3000F to 50 -

3500F, This modification will allow the temperature to be determined under anticipated PRT conditions.

The remaining RG 1.97 position still under review is the need to provide instrumentation to monitor containment emergency sump water temperature. The design of the VEGP emergency core cooling and long term cooling systems is such that containment emergency sump water temperature is not a key parameter for post-accident recovery or operation. The emergency operating procedures (EOPs) do not contain operator actions dependent on sump temperature.

Initiation of recirculation flow is based on ref ueling water storage tank level, not on containment sump temperature. If the operator desires to lower the sump temperature during cooldown, the only option available is to initiate operation of the other residual heat removal (RHR) train, assuming one has been stopped. However, the decision to take that action would be based on RCS

} te mpe rature , inadequete cool-down rate, or RCS pressure, not sump tempe ratu re. In no situation would the decision be made to stop RHR operation, as the RifR system g.ovides the only means for reducing sump tempe rature. As shown in FSAR sub paragraph 6.3.2.2.4, the sump temperature would not rise to the point where the RIR pump NPSH would be inadequate, even with only one RHR pump operable. (

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f Director of Nuclear Reactor Regulation File: X7BC35 January 21, 1986 Log:- GN-784 Page 2 Although the determination of containment sump temperature is not essential for post accident operation, the operators nay at some time desire that information for a more complete understanding of the plant status. In that case, containment sump temperature could be determined directly using existing instrumentation located inside containment and on the RHR heat exchanger inlet piping. However -these instruments are not fully qualified for the harsh environments they could be subjected to. The sump temperature instruments and cable inside containment are qualified but the electrical connections at the instruments and at the penetrations are not qualified for a steam environment. The RHR inlet temperature instruments are not qualified for the high radiation levels that may be present in the heat exchanger rooms.

In conclusion, determination of containment emergency sump water temperature is not required for post accident operation and achieving cold shutdown. If this determination becomes desirable, it can be made by direct indication f rom unqualified instruments. Consequently, the existing design is adequate, and the addition of qualified instrumentation would not increase the safety of the plant or the ability to bring the plant to a safe condition following an accident.

Following the resolution of this final item, the FSAR will be revised to reflect the two design changes described above, and the final position on containment sump temperature.

If you have any questions, please contact me.

Si erely,

. f.

J. A. Bailey Project Licensing Manager JAB /dla Attachment xc: 'R. E. Conway G. Bockhold, Jr.

R.' A. Thomas T. Johnson J. E. Joiner, Esquire D. C. Teper B. W. Churchill, Esquire L. Fowler M. A. Miller W. C. Ramsey B. Jones Vogtle Project File L. T. Cucwa 0053V

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