ML19270G474

Discusses Mod of Operating Guidelines for Small Breaks.Hpi Must Remain in Operation Until LPIS Is in Operation & Flowing in Excess of 1,000 Gallons/Minute in Each Line & Stable for 20 Minutes

ML19270G474
Person / Time
Site:	Arkansas Nuclear
Issue date:	05/30/1979
From:	Taylor J BABCOCK & WILCOX CO.
To:	Novak T Office of Nuclear Reactor Regulation
References
NUDOCS 7906080306
Download: ML19270G474 (2)

Text

., s Babcock &Wilcox ,c.e, cene,ancn c,ce, P.O. Box 1260, Lynchburg, Va. 24505 Telephcne: (804) 384-5111 May 30, 1979 Mr. T. H. Novak, Chief Reactor Systems Branch Division of System Safety Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, DC 20555

Subject:

Operating Guidelines for Small Breaks for Arkansas

Dear Mr. Novak:

The BGW operator guidelines for small breaks, letter-J. H. Taylor (B6W) to Z. R. Ros: toc y (NRC) May 16, 1979, states in Section 3.1 that the HPI system must remain in operation until one of two criteria is satisfied. One of these criteria states ( 3.1.1 ) :

"The LPI system is in operation and flowing at a rate in excess of 1000 gpm in each line and the situation has been stable for 20 minutes." The purpose of this criteria is to ensure that, in the event of a break in the core flooding line, at least 1000 gpm is being supplied to the reactor vessel. This flow assures sufficient cooling such that core uncovery would not occur following termination of the HPI system.

The Arkansas LPI system has passive cross-connects (cavitating venturis) located downstream of the flow measuring devices. In order to ensure that 1000 gpm is delivered to the reactor vessel in the event of a core flooding line break for the Arkansas LPI system, the operator guidelines for small breaks, as given in the May 16 letter, must be modified as follows for Arkansas:

~

3.0 Precautions 3.1 If the HPI system has actuated because of a low pressure condition, it must remain in operation until one of the following criteria is satisfied:

2337 218 000A S /0 The Batcccx & i*h!ccx Comcany ' Estansned 1867 7906080 %f

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Babcock &VAlcox Mr. T. H. Novak May 30, 1979

1. If one LPI pump is in operation, it must be flowing at a rate in excess of 3020 gpm and the situation has been stable for 20 minutes.

If two LPI pumps are in operation, they must each be flowing in excess of 2630 gpm and the situation has been stable for 20 minutes.

or

2. Remains as in May 16 letter.

All other portions of the operator guidelines for small breaks in the May 16 letter remain applicable for Arkansas.

If you have any questions on these quidelines please contact Mr. E. R. Kane of my staff (Ext. 3740).

Very truly yours

?bndk.

J. H. Taylor Manager, Licensing JHT/fw cc: R. B. Borsum - B6W (Bethesda) 7777 71n LaJt LI7

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