ML20203C145

Submits Description of Evaluation Method Discussed in 971204 Telcon Re BE-LBLOCA Evaluation for SG Replacement Project

ML20203C145
Person / Time
Site:	Farley
Issue date:	12/09/1997
From:	Dennis Morey SOUTHERN NUCLEAR OPERATING CO.
To:	NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM)
References
NUDOCS 9712150241
Download: ML20203C145 (4)

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. Dave Morey Southern fisclear

, We Piewent Operating Company Iatley Frtyect PO Box 1295 (9tminpam.kabama 35201 Tel ?05 932.5131  ;

SOUTHERN h December 9, I997 COMPANY 7,,,p ,, 3,,,, y,,, 7,,y.

Docket Nos.: 50-348 3 364 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555 Joseph M. Farley Nuclear Plant (FNP)

Phone Conference to Discuss BE LBLOCA Evaluation For the Steam Genera 1or Replacement Proitet Ladies and Gentlemen:

On December 4,1997, a phone conference was held between the NRR Staff, Westinghouse LOCA Staff and Sotahern Nuclear-Farley Project NEL Staff. In attendance on the phone conference were, Jake Zimmerman and Fred Orr representing NRR, Mike Watson and Sue Dederer representing Westinghouse, and John Garlington, Mark Ajiuni, and lioward Mahan representing Soutbarn Nuclear. The purpose of the conference was to discuss the type of evaluations Westinghouse would perform for the BE-LBLOCA calculation to support the replacement of the Steam Generators at Farley Nuclear Plant Units 1 and 2.

Sue Dederer of Westinghouse described the method that will be used to evaluate BE-LBLOCA for Farley Nuclear Plant. An open discussion was held with the NRR Staff to better understand the methods that are to be used. The Enclosure contains a description of the evaluation method that was discussed.

SNC & Westinghouse believe that the proposed approach for r 41uating the replacement of Steam Generators is sound and that a full scope BE-LBLOCA reanalysis is not required. Due to the significant adverse impact to the licensing schedule for Steam Generater replacement,

-which would occur if this approach was deemed insuflicient aller submittal of the primary licensing package, SNC requests that the Staff review this proposed method and provide comments by January 16,1998. l hY l L!l[El5,3,3,3Jg 97ihiiod41971209 PDR ADOCK 05000348 p- PDR

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' U S. Nuclear Regulatory Commission Page 2 If you have any questions, please advise.

I Respectfully submitted,  :

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cc: Mr. L A Reyes, Region 11 Administrator .

Mr. L 1, Zimmerman, NRR Project Manager

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ENCLOSURE 13E-LDLOCA Analysis for Farley Nuclear Plant to Support IlmStemILGenerator Replacement Project

, Enclosure BE LBLOCA Analysis for Farley Nuclear Plant to Suppon Ib1Sirmn.Osnestor ReplKunenLPwisd Steam Generator Replacement (SGR) programs for standard LBLOCA have been evaluated by running the limiting transient which resulted in the analysis of record (AOR) with the new steam generator parameters incorporated. This approach results in a PCT impact which is then incorporated into the PCT rack ups. For the Farley BE LilLOCA analysis supporting the SGR, a similar approach is proposed in which the limiting reference transient is used as the basis for evaluation.

A SGR program of the type contracted by Southem Nuclear for the Farley Units I and 2 is not expected tt yield any large changes in the BE-LDLOCA transier:t results. The SGR program for Farley has been set up such that there will be no changes to the major plant operating paramete s listed in Table 13-1 of the response to RAl 3, question 13, for the Farley Uprate program, as transmitted under letter dated November 19,1997. There will be no change to the analyzed thermal

, design flow, Tavg window, Tech Spec limits, ECCS parameters or fuel type. The only changes required will be the physical changes associated with the steam generator: the primary and secondary volume, fluid mass, physical dimensions, etc. Thus, the basis for the BE large break >

analysis for Farley will not change: the initial condition run matrix, power distribution run matrix and global model mn matrix will all remain the same.

Westinghouse propov,s to perfonn two WCOBRA/ TRAC calculations for the replacement sto^m generator program using the limiting reference transient identifici in the BE analysis for Farley at uprated conditions as the basis. The limiting reference transient is a CD=1.0 split break with low Tavg and no loss of offsite power foc Unit 2 (as described in section 6.1.1.5.2 of WCAP 14722, dated November 1997). The replacemeat steam generators will be incorporated into the decks and two calculations will be performed; one at maximum and one at minimum tube plugging levels.

The results of these two calculations will be compared to the result of the original reference transient, if the original reference transient remains limiting, the SGR will be considered to be bounded by the current BE-LBLOCA analysis, and no further analysis will be necessary, ifone of these two transients becomes more limiting than the original reference transient, a modified approach will be taken. Since the SGR program does not change any parameters associated with the three phases of uncertainty (initial condition, power distiibution, or global model), only the fmal phase of the BE methodology would need to be assessed. This phase involves the combination of

. parameters which were not presiously varied in combination in the first three phases of uncertainty, as discussed in Section 2.43.5 of the SER for the approved BE LBLOCA methodology. As such, eight additional calculations, known as suoerposition calculations, which combine two or more of the limiting parameters in one calculation would be perfonned. The limiting SGR calculation would be used as the basis to perform the eight superposition mns with the SGR conditions. The results of these superposition runs will then be used to calculate a new 95% probability PCT. This would then be compared to the original 95% PCT for the Farley uprate analysis (2064 deg F). The difference in PCT would be used to assess a delta PCT to be used in the PCT rackup for the Farley units, similar to what is done for non BE evaluation models. Other evaluations based on the final PCT, such as Zirc-4 vs, Zirlo fuel, will also be re-evaluated.