ML19338C584
| ML19338C584 | |
| Person / Time | |
|---|---|
| Site: | Arkansas Nuclear  |
| Issue date: | 08/01/1980 |
| From: | Trimble D ARKANSAS POWER & LIGHT CO. |
| To: | Reid R Office of Nuclear Reactor Regulation |
| References | |
| 2-060-23, 2-60-23, NUDOCS 8008180190 | |
| Download: ML19338C584 (2) | |
Text
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ARKANSAS POWER & LIGHT COMPANY POST OFFICE BOX 551 LITTLE ROCK. ARKANSAS 72203 [501)371-4000 August 1, 1980 2-060-23 Director of fluclear 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 2 Docket No. 50-368 License No. NPF-6 Proposed Technical Specification Change - EFW Pum Response Time (File:
2-1511.1 Gentlemen:
In response to your letter of April 4,1980, the following replies are provided.
Question 1.
You have verified through your NSSS vendor that no credit was taken in the Arkansas Nuclear One, Unit No. 2 safety analysis for delivery of emergency feedwater from either pump prior to 97.4 seconds following an actuation signal.
Provide the safe-ty analysis which will show that no credit was taken prior to 97.4 seconds or identify the reference in the docket which will do the same.
Response
The ANO-2 FSAR provides two time limits above which credit is taken for emergency feedwater delivery.
(1) 65 seconds, following an actuation signal, for transients with AC power available.
(2' 118 seconds, following an actuation signal, for transients without AC power.
The first case was reanalyzed by the NSSS vendor to provide justification for the 97.4 second delay time for the delivery of emergency feedwater. The analysis showed the RCS pressure remained within acceptable limits ((2750 psia); that the fuel design limits and radiological consequences were not impacted; and the DNBR limit remained above the specified acceptable fuel design limit of 1.3.
8008180/4 0 MEMBER M.OOLE SOUTH UTILITIES SYSTEM
Mr. R. W. Reid August 1, 1980 The second case did not need to be reanalyzed as emergency feedwater delivery was already assumed (in the FSAR) to be 118 seconds after the actuation signal. A feedwater line break was assumed concurrent with a loss of AC power.
The delivery of emergency feedwater to the intact steam genera-tor and the opening of the primary safety valves limit the RCS pressure and prevent filling of the pressurizer.
Question 2.
Provide supporting analysis which will show that there would be no decrease in the safety margin if this TS change would be implemented.
Response
Although the existing ANO-2 FSAR analyses take credit for EFW delivery after 65 seconds in the first case above, it can be seen from the FSAR analyses that no credit needs to be taken until after 97.4 seconds. This analysis shows that the RCS pressure remains within acceptable limits; that the fuel design limits and radiological consequences are not impacted; and the DNBR limits reiaain above the specified ac-ceptable fuel design limits of 1.3.
Thus there would be no significant or unacceptable decrease in the safety margin if this TS cnange were implemented.
Very truly yours,
& ?.
David C. Trimble Manager, Licensing DCT:DEJ:ms l
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