ML20136B914

Forwards Evaluation of Procedure for Filling & Operation of once-through Steam Generator B Water Solid

ML20136B914
Person / Time
Site:	Three Mile Island
Issue date:	04/24/1979
From:	Novak T Office of Nuclear Reactor Regulation
To:	Stello V Office of Nuclear Reactor Regulation
References
NUDOCS 7909130135
Download: ML20136B914 (3)

Text

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NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 7.

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MEMORANDUM FOR: Victor Stello FROM- NRR Technical Review Group E'J BJ E C T: SYSTEMS ANALYSEE OF FILLING AND ODERATION Or OTSG "B" .'A TER SOL ID

.le . ave ev i esec t he n re l ir.i na ry c ro:ecu re o ' f i l l i ng OTCG 'E solid with water and the conce:tual transition o# o! acine CTSG

'B' in operation while the s teaming OTSG 'A" would be conve ted to water solid operation. Enclosed is our eva l ua t i or, .

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NRC Techni ca l Review Groua In:losure:

lcter Sciid Filling cnc Cr3 atior of C TSG B

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.;RC Technical Group '4) g i

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l WATER COLID FILLiflG AND OPERATION 07 ETEAM GENE RATOR "3 1

Present leakage rates of the OT5G "B" tubes pro" ides an cooortunity !l to fill the OTSG "B' water solid. We have reviewed draft procedures for this operation to see that orecautions would be taken to avoid water nommer in the steam line and any otne eaverse effects. We have not identified any significant risk witn operation o' OTSG "B" ir, a water solid mode.

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We support the procedure which suggest that precautions be followed l when filling the secondary side of OTSG "S" slowly in order to avoid water hammer.

Th : steam line to the isolation valves and the turbine bycass line to the turbine bypass control valve will ne filled with water. To avoid notential water hammer, we recommend that the emergency ricam generator Feed puma be secured. The OTSG li' cool i ng wil l be arought on line by cracking ooen the turbine byoass valve.

Once tne steam generator "B" side filling process has been completed transition will take place to fill steam generator "A" side water solid. The licensee has informed us that during this transition, t ne O TSG 'B" fl ow rate will start and gradually increase while s imul taneously the ope rat ing 0TSG A" s ide will be controlled (by tnrottling turbine valves) to decrease cooling. Once the OTSG ' B' has taken up tne 'ull Inad, OTSG A" will be 'so!ated and filled water solid by the sa e crocedure f ol! awed wi th OTSG B'. We agree

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with the above described concept, however, details o# valve line uo and checks for proper filling indications will be reviewed as part o' the staf#'s review of the coerating procedure for entering this moo, of operation.

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