ML20198K040

Informs That NRC Has Provided SER Input to Standardization Project Directorate Re Loftran Transient Analysis Computer Code (Chapter 21)

ML20198K040
Person / Time
Site:	05200003
Issue date:	10/16/1997
From:	Huffman W NRC (Affiliation Not Assigned)
To:	Liparulo N WESTINGHOUSE ELECTRIC COMPANY, DIV OF CBS CORP.
References
NUDOCS 9710230016
Download: ML20198K040 (3)

Text

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October 16, 1997 Mr. Nicholas J. Liparulo, Manager Nuclear Safety and Regulatory Analysis Nuclear and Advanced Technology Division Westinghouse Electric Corporation P.O. Box 355 Pittsburgh, PA 15230

SUBJECT:

OPEN ITEMS ASSOCIATED WITH AP600 SAFETY EVALUATION REPORT (SER) 0F THE LOFTRAN-COMPUTER CODE

Dear Mr. Liparulo:

The Reactor Systems Branch (SRXB) of the Nuclear Regulatory Commission (NRC) has provided an SER input to the Standardization Project Directorate related to the LOFTRAN transient analysis computer code (SER Chapter 21). The staff is still evaluating information Westinghouse has recently submitted on the passive residual heat removal (PRHR) heat exchanger heat transfer correlations and LOFTRAN sensitivity to thermal-stratification in the in-containment-refueling water storage tank (IRWST). However, for tracking purposes, these items have been designated as open itens associated with the LOFTRAN SER and are enclosed with this letter.

If you have any questions regarding this matter, you may contact me at (301) 415-1141.

Sincerely, original signed by:

William C. Huffman, Project Manager Standardization Project Directorate Division of Reactor Program Management Office of Nuclear Reactor Regulation Docket No.52-003

Enclosure:

As stated cc w/ encl: See next page NPO) 41 DISTRIBUTION:

Docket File -PDST R/F JWPoe PUBLIC DMatthews TRQuay TKenyon BHuffman JSebroksy DScaletti JNWilson JMoore, 0-15 B18 L l WDean, 0-5 E23 ACRS (11) TCollins, 0-8 E23 RCaruso, 0-8 E2 Alevin, 0-8 E23 RLandry, 0-8 E23 GHolahan, 0-8 E2 SNewberry, 0-8 E23 DOCUMENT NAME: A:LOFTRAN.SER w ..iv. . ..,, .e w. 4.. 6,4.. i. ih. 6..: e . c.,, unhoui .tt.cian.ni/.new. r copy wah .tt. chm.ni/.nclosur. 'N' . No copy 0FFICE PM: POST:DRPM BC SRXB:DJSh D:PDST:Q8PL l NAME WCHuffmankC)W"l'Collin'#4'V TRQuay ]M';7_

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Mr. Nicholas J. Liparulo Docket No.52-003 Westinghouse Electric Corporation AP600 cc: Mr. B. A. McIntyre Mr. Russ Bell Advanced Plant Safety & Licensing Senior Project Manager, Programs Westinghouse Electric Corporation Nuclear Energy Institute Energy Systems Business Unit 1776 I Street, NW P.O. Box 355 Suite 300 Pittsburgh, PA 15230 Washington, DC 20006-3705 Mr. Cindy L. Haag Ms. Lynn Connor Advanced Plant Safety & Licensing Doc-Search Associates Westinghouse Electric Corporation Post Office Box 34 Energy Systems Business Unit cabin John, MD 20818 Box 355 Pittsburgh, PA 15230 Dr. Craig D. Sawyer, Manager Advanced Reactor Programs Mr. Sterling Franks GE Nuclear Energy U.S. Department of Energy 175 Curtner Avenue, MC-754 NE-50 San Jose, CA 95125 19901 Germantown Road Germantown, MD 20874 Mr. Robert H. Buchhoir GE Nuclear Energy Mr. Frank A. Ross 175 Curtner Avenue, MC-781 U.S. Department of Energy, NE-42 San Jose, CA 95125 Office of LWR Safety and Technology 19901 Germantown Road Barton Z. Cowan, Esq.

Germantown, MD 20874 Eckert Seamans Cherin & Mellott 600 Grant Street 42nd Floor Mr Charles Thompson, Nuclear Engineer Pittsburgh, PA 15219 Aro00 Certification NE-50 Mr. Ed Rodwell, Manager 19901 Germantown Road PWR Design Certification Germaniawn, MD 20874 Electric Power Research Institute 3412 Hillview Avenue Palo Alto, CA 94303 l

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i SER OPEN ITEMS ASSOCIATED WITH AP600 LOFTRAN TRANSIENT ANALYSIS CODE l

440.735F _The NRC staff has raised concerns about modifications to the LOFTRAN heat  !

transfer correlations for ap)11 cation to the outside of the PRHR tubes. '

The applicability of straigit tube data to the C-tube design of the PRHR requires staff review and acceptance of Westinghouse confirmatory analysis of selected ROSA test data.

440.736F The NRC staff is concerned about the effect of thermal stratification in the IRWST and what impact it may have on the results of AP600 non-LOCA -

transient analyses. The staff must review and accept the Westinghouse LOFTRAN sensitivity study results related to IRWST thermal stratifica-tion.

440.737F Westinghouse has indicated in a response to requests for additional information that the approved PWR version of LOFTRAN and the AP600 version of the code may be merged and maintained as one code. The staff is to be informed if this occurs and-it will become an additional code audit issae. .

9 l Enclosure

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