ML20203E625

Forwards Supplemental Response to Audit Finding 1 Re Deconvolution Analysis & Validation of Ebasco Foundation Spring Modeling for Elastic Half-Space Seismic Model, for Review & Comments as SER Input

ML20203E625
Person / Time
Site:	Satsop
Issue date:	07/14/1986
From:	Sorensen G WASHINGTON PUBLIC POWER SUPPLY SYSTEM
To:	Knighton G Office of Nuclear Reactor Regulation
Shared Package
ML20203E630	List: ML20203E625 ML20203E632
References
GO3-86-399, NUDOCS 8607240189
Download: ML20203E625 (4)

Text

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Washington Public Power Supply System Box 1223 Elma, Washington 98541-1223 (2061482-4428 July 14, 1986 G03-86-399 Docket No. 50-508 Director of Nuclear Reactor Regulation Attention: G. W. Knighton, Director PWR Project Directorate No. 7 U. S. Nuclear Regulatory Commission Washington, D. C. 20555

Subject:

NUCLEAR PROJECT N0. 3 RESOLUTION OF KEY LICENSING ISSUES DECONVOLUTION ANALYSIS

References:

a) Letter (G03-84-410), GC Sorensen to GW Knighton, subject, "NRC Structural Design Audit", dated June 27, 1984.

b) NRC and Supply System Meeting, July 10, 1984.

In Reference a), the Supply System provided the final responses to all but one (Audit Finding #4) of the outstanding Structural Engineering Branch Design Audit Findings. The findings resulted from the audit conducted at Ebasco's New York offices on September 26, 1983. A separate submittal within the next month will provide a response to Audit Finding #4.

I 8607240189 860714 PDR ADOCK 05000508 l

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Director of Nuclear Reactor Regulation G03-86-399 Attention: G. W. Knighton, Director July 14, 1986 Page Two At the Reference b) meeting, the Supply System presented an explanation of our results regarding Audit Finding #1 on deconvolution analysis. The NRC Staff in attendance at that meeting had several questions about our response to that audit finding. The attachment to this letter provides a supplemental Supply System analysis that substantiates the previous Reference a) submittal.

This submittal combined with the Reference a) submittal provides the NRC with a complete response to the Audit Finding #1 concerns. In a fashion similar to our submittals to the NRC regarding resolution of other key licensing issues (Draft SER, geology / seismology, and stiff clamps), the Supply System requests that the NRC review our responses to Audit Finding #1 and document its review via issuance of a Safety Evaluation Report (SER) section. Both the Supply System and the NRC have expended considerable effort on this issue.

Resolution with our presently available personnel that are knowledgeable of this issue will ensure that valuable work need not be redone in the future with different personnel. In addition, to the extent that this issue contributes to uncertainties regarding the estimate to complete WNP-3, its resolution would incrementally reduce those uncertainties and provide greater confidence in the ability to obtain an Operating License in a cost effective manner. All parties have much to gain if the work done to date can be completed and formally documented.

If you have any questions, please contact Mr. D. W. Coleman, WNP-3 Project Licensing Manager, Ext. 5436.

G. C. Sorensen, Manager Regulatory Programs DWC/cae Attachment cc: Mr. J. A. Adams, NESCO Mr. M. F. Barnoski, Combustion Engineering Mr. R. M. Boucher, Pacific Power & Light Co.

Mr. W. L. Bryan, Washington Water Power Co.

Mr. G. Dick, NRC Mr. W. J. Finnegan, Puget Sound Power & Light Co.

Mr. J. R. Lewis, BPA Mr. M. Pierson, Ebasco - New York j Mr. N. S. Reynolds, Bishop, Liberman, Cook, Purcell & Reynolds Ms. R. M. Taylor, Ebasco - Elma Mr. B. D. Withers, Portland General Electric Co.

! Mr. H. Worchel, Ebasco - New York

• Document Control Desk - U. S. NRC

• 40 copies of the attachment

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e WASHINGTON PUBLIC POWER SUPPLY SYSTEM NUCLEAR PROJECT NO. 3 AUDIT FINDING NO. 1 SUPPLEMENTAL RESPONSE l

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July 1986 l

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7 AUDIT FINDING NO. 1 In order to proceed with the audit, it was decided to discuss with Ebasco the deconvolution analysis for the plant. This issue was previously raised in review of the FSAR. Ebasco has applied the deconvolution methodology to a -

finite element model of the rock site. Since the rock is essentially elas-tic, in the range of interest, a reduction in motion at the base mat from that postulated at the surface would not be expected. In the analysis, credit was taken for sucts a reouction and the staff has disagreed that sucn results would not be expected for a rock site.

Accordingly, the staff will require tnat the recommiendations of NUREG 0800, Section 3.7.2 will be followed. Specifically, either an elastic half-space analysis should be performed to confine the finite elements analysis, or the site should be considered as a rock site, and a fixed-base analysis should be performed. In any case, the full value of the SSE/0BE should be input at the base mat without reduction.-

RESPONSE TO FINDING NO. 1 An elastic half-space approach of seismic dynamic analysis of Category I structures has been perfonned in response to tne staff's request. The analy-sis results confirm the acceptability of the finite element / boundaries approach employed for the WNP-3 seismic design.

The details of tne elastic half-space analysis and comparison of the analysis results to the WNP-3 design basis were previously presented in Attachment 1 of Letter No. G03-84-410, dated June 27, 1984.

The following attachment is tne Owner's analysis to validate the model and _

boundary conditions applied by Ebasco in deriving the horizontal foundation stiffness attrioutable to embedment effects and is supplemental to the pre-vious information sent to tne NRC via Letter No. G03-84-410.

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