ML20197B926
| ML20197B926 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 10/27/1978 |
| From: | David Williams ARKANSAS POWER & LIGHT CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 7811080136 | |
| Download: ML20197B926 (2) | |
Text
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g ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 LITTLE ROCK. ARKANSAS 72203 (5011371-4000 October 27, 1978 2
Director of Nuclear Reactor Regulation ATTN:
Mr. R. W. Reid, Chief Operating Reactor Branch #4 U.
S. Nuclear Regulatory Commission Washington, D. C.
20555
Subject:
Arkansas Nuclear One-Unit 1 Docket No. 50-313 i
License No. DPR-51 Sequencing Electrical Loads on Startup Transformer (File:
1510, 6012) l i
Centlemen:
The following is provided to document the telecon, earlier this date, between Mr. G. Vissing, et.al., and Mr. T. Enos.
Our letters of October 25 and October 27, 1978, on the above subject, proposed modifications and testing methods we will implement by October 31, 1978, to alleviate the possible undervoltage situation on the startup transformer. We understand, from the above telecon, that these modifications are acceptable to the staff.
We further understand that our method of testing the modified circuitry is acceptable and l
sufficient to assure proper operation of the sequencing circuitry.
l Per your verbal request, the following provides further assurance that the ANO-1 ECCS systems are available and can not be subjected to a severe degraded voltage condition in the interim until the sequencing modifications are complete.
We will, on this date, power busses Al and A3 from Startup Transformer
- 2 (SU2).
Busses A2 and.A4 will be powered from the unit auxiliary transformer (UA).
The reverse of this arrangement is also possible (Al/A3 on UA and A2/A4 on SU2). We will further place the appropriate breakers in the " pull-to-lock" position such that:
- 1) ANO-2 cannot receive power from SU2.
- 2) Busses Al/A3 and A2/A4 cannot be transferred automatically to the same transformer.
This will assure that both trains of the ECCS system cannot automatically transfer to the same transformer.
This will reduce loads on each trans-former such that the ECCS systems could not possibly be subjected to a 78M~OSDIN
\\ D ME MPER MiOOL E SOUTH UT!LiTIES SYS TEM
Mr. R. W. Reid October 27, 1978 severe degraded voltage and further assures operability of the ECCS systems under any postulated mode of operation.
We will maintain the busses separated as described above until our sequencing modifications are complete at which time we will revert to normal breaker alignments.
We trust these commitments are sufficient to resolve your concerns on this issue.
Very truly yours, r-~~, jf
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4 Daniel 11. Williams
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Manager, Licensing DilW:JTE:vb
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