ML19276G927

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Submits Ltr to Document 790813 Telcon.Discusses Proportional Pressurizer Heaters & in House Investigation
ML19276G927
Person / Time
Site: Arkansas Nuclear Entergy icon.png
Issue date: 08/21/1979
From: Trimble D
ARKANSAS POWER & LIGHT CO.
To: Ross D
Office of Nuclear Reactor Regulation
References
2-089-8, 2-89-8, NUDOCS 7908280656
Download: ML19276G927 (1)


Text

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ARKANSAS POWER & LIGHT COMPANY ,

POST OFFICE BOX 551 LITTLE ROCK. ARKANSAS 72203 (501)371-4000 August 21, 1979 2-089-8 Mr. D. F. Ross, Jr., Director Bulletins & Orders Task Force Office of Nuclear Reactor Regulation Nuclear Regulatory Commission Washington, D.C. 20555

Subject:

Arkansas fluclear One-Unit 2 Docket tb. 50-368 License No. NPF-6 Pressurizer Heaters (File: 2-1510)

Gentlemen:

The following is provided to document the August 13, 1979, telecon between your Mr. Villaiva and our Mr. White.

As stated by Mr. White, two proportional pressurizer heaters a e powered from redundant 480 V. vital power buses. The proportional heaters are shed from the vital power buses if a SIAS is generated and power is being supplied by the Emergency Diesel Generators. The presence of the SIAS prevents tne proportional heaters from being manually loaded onto the vital power buses unless the signal lockout is bypassed. We have iden-tified a method of bypassing the SIAS proportional heater lockout relays.

Our operations staff estimates that the subject relays (2) can be by-passed in less than 30 minutes. We have not analyzed the consequences of loading the proportional heaters, post LOCA, onto the vital power buses when pcwered by the Emergency Diesel Generators. As discussed with your Mr. Villaiva, we believe that curing the time period when the proportional heaters would be of use the Diesel Generators have the necessary capacity to accept the additional load without causing an -

undervoltage condition. We are investigating this in-house for our own informatien.

Very truly yours, m  ?

e ch David C. Trimble Manager, Licensing DCT:M0W:nak 7908280(600 2041 197 MEMf4E A MtOOLE SOUTH UTILITIES SYSTEM