ML20209C079

Discusses Review of SER Confirmatory Item 21 Re Multiflex 3.0 Used for Determining thermal-hydraulic Loads Resulting from Loca.Nrc Should Be Able to Close SER Confirmatory Item 21 Through Qualitative Assessment.Points to Consider Listed

ML20209C079
Person / Time
Site:	Beaver Valley
Issue date:	04/22/1987
From:	Carey J DUQUESNE LIGHT CO.
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
2NRC-7-088, 2NRC-7-88, TAC-62904, NUDOCS 8704280582
Download: ML20209C079 (3)

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M 2NRC-7-088 Bea e Vall o. 2 Unit Project organization Te6ecopy 2) 3-5 Ext.160 P.o. Box 328 April 22, 1987 Shippingport, PA 15077 United States Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555

SUBJECT:

Beaver Valley Power Station Unit No. 2 Docket No. 50-412 Review of MULTIFLEX 3.0 - SER Confirmatory Item No. 21

REFERENCE:

A) NRC letter dated March 30, 1987 to Mr. J. J. Carey from Mr.

Lester S. Rubenstein B) Westinghouse letter NS-EPR-2644, dated August 19, 1982 to Mr.

James R. Miller from Mr. E. P. Rahe, Jr.

C) DLC letter 2NRC-4-203, dated December 10, 1984 D) DLC letter 2NRC-5-057, dated March 29, 1985 E) Westinghouse letter NS-NRC-85-3041, dated June 18, 1985 F) DLC letter 2NRC-6-002, dated January 3,1986 G) NRC letter dated August 7,1985 to Mr. E. P. Rahe, Jr. from Mr.

C. Thomas Gentlemen:

As acknowledged by the Staff in Reference A and in Section 4.2.3 of the Beaver Valley Power Station Unit No. 2 Safety Evaluation Report, the review of the computer code MULTIFLEX 3.0 used for determining thermal-hydraulic loads resulting from a LOCA has been a lengthy process. MULTIFLEX 3.0 was first submitted by Westinghouse on August 19,1982 (Reference B) . Westinghouse and Duquesne Light Company (DLC) have supported the staff's review. Many working level telephone conferences and meetings were held with the Staff and an addi-tional WCAP was prepared by Westinghouse to specifically address the numerous NRC review questions on MULTIFLEX 3.0 (References C through F). The NRC acknowledged in Reference G that "all the necessary documentation" has been submitted "so that the report can be reviewed as a plant specific document."

During this entire period the Staff has not identified any major technical conceras.

The staff suggested in Reference A tnat DLC abandon their pursuit of Staff approval for MULTIFLEX 3.0 and its associated future use, in favor of devel-oping new and additional analyses to take advantage of the recent General Design Criterion 4 exemption and regulation changes. DLC, through discussions with Westinghouse, has concluded that, even if credit is taken for GDC 4 changes, the new analyses would not result in a " minimal analytical effort" as suggested in Reference A. As demonstrated by the References, DLC has already invested extensive time and resources in developing MULTIFLEX 3.0 and 8704280582 870422 R ADOCK 05000412 PDR h{

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l United States Nuclear Regulatory Commission Review of MULTIFLEX 3.0 Page 2 -

l i supporting its application to Beaver Valley Power Station Unit No. 2. DLC believes that the staff has had sufficient time to review this code which is basically a refined version of MULTIFLEX 1.0. Approval of MULTIFLEX 3.0 is still preferred by DLC as it would also facilitate its future use.

T h e Staff should be able to close SER Confirmatory Item 21 through quali- )

tative assessment instead of performing a formal review of MULTIFLEX 3.0. The qualitative assessment could consider points such as the following:

j 1. The 3-loop design used at BVPS-2 is sufficiently similar to other j 3-loop plants already reviewed and accepted by the staff. Some of i these plants are located in regions of higher seismic activity than l BVPS-2. Non-seismic loading should cat be substantially different i from all other 3-loop plant designs. '

2. Reduction of postulated LOCA loads due to recent GDC 4 changes can be judged as showing that conservatism in previously analyzed plants exceeds that which was assumed at the time of analysis and is great-er than that which the staff found to be acceptable on those

pl ants .

3. A plant specific analysis has been performed for BVPS-2. This ,

analysis employed a revised computer code which is basically a  !

refinment of a previously approved and accepted code (MULTIFLEX j 1.0).

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It should be noted that OLC has not evaluated such a basis.

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United States Nuclear Regulatory Commission Review of MULTIFLEX 3.0 j Page 3 i

DLC would also be willing to extend the Staff review of MULTIFLEX 3.0 into 1988 as suggested by the staff in Reference A. This would necessitate that the Beaver Valley Power Station Unit No. 2 operating license contain a condition granting interim approval for MULTIFLEX 3.0 use until the Staff completes its

! review and approval .

l DUQUESNE LIGHT COMPANY n By _ _ _ _

K d. Tarey V '

Senior Vice President

> l RWF/ijr NR/RWF/MULTIFLX ,

AR/NAR l cc: Mr. P. Tam, Project Manager Mr. J. Beall, NRC Sr. Resident Inspector Mr. L. Prividy, NRC Resident Inspector .

INP0 Records Center NRC Document Control Desk a

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