ML20128D223

Summary of 850618 Meeting W/Util in Bethesda,Md Re Reanalysis of rock-structure Interaction

ML20128D223
Person / Time
Site:	Comanche Peak
Issue date:	06/24/1985
From:	Burwell S Office of Nuclear Reactor Regulation
To:	Office of Nuclear Reactor Regulation
Shared Package
ML20128D218	List: ML20128D215 ML20128D223 ML20128D243
References
NUDOCS 8507050060
Download: ML20128D223 (2)

Text

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" ~ UNITED STATES

'n NUCLEAR REGULATORY COMMISSION h .g WASHINGTON, D. C. 20555

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1. JW 2 41985 Docket Nos.: 50-445 and 50-446 APPLICANT: Texas Utilities Generating Company (TUGCO)

FACILITY: Comanche Peak Steam Electric Station, Units 1 and 2 (CPSES)

SUMMARY

OF MEETING BETWEEN NRC STAFF AND TUGC0 TO DISCUSS THE REANALYSIS OF ROCK-STRUCTURE INTERACTION FOR COMANCHE PEAK At the request of TUGCO, a meeting between the NRC staff and TUGC0 was held on June 18, 1985 in Room P-422, Phillips Building, 7920 Norfolk Avenue, Bethesda, Maryland. The meeting was transcribed and the transcript is en-closed. The transcript contains a listing of the meeting attendance and the slides used by TUGC0 during its presentation.

The applicant, TUGCO, had commissioned a reanalysis of the rock-structure interaction for Comanche Peak. The objective of the reanalysis was to assess the seismic margin in the in-structure floor response spectra considering im-provements in the technology that have occurred since the response spectra given in the FSAR were developed. The meeting consisted of descriptions of the basic seismic design criteria, the site foundation conditions, the earlier analysis for developing the in-structure floor response spectra used heretofore, the major steps and methodology used in the reanalysis, and the results of the reanalysis on the response spectra for the auxiliary building, as an example.

The NRC staff raised questions concerning conformance of the reanalysis to the Standard Review Plan and to the designs used in other nuclear plants reviewed and accepted by the NRC. The staff also requested additional information on whether the reanalysis is an improvement in the analytical methodology, or is there data to demonstrate that the results more accurately reflect the response of a structure to earthquake excitation. The applicant's reanalysis had used a layered base model to depict the rock conditions at the site. The pros and cons of using a fixed base model verses a layered base model were discussed in considerable detail.

The staff cautioned the applicant that should TUGC0 make an submittal, it should be very clear on how they intend to use the results of the reanalysis.

If the results are to have only a limited application, then justification for restricting its application should be provided.

8507050060 850624 PDR T ADOCK 05000445 PDR

_2_

At the close of the meeting the applicant advised that they will evaluate whether a submittal requesting NRC acceptance of the reanalysis should or should not be made. If that decision is affirmative, they will further evaluate whether the submittal will be founded on the layered base model presented at the meeting or on a fixed base model.

S. B. Burwell, Project Manager Licensing Branch No. 1 Division of Licensing

Enclosure:

As stated cc: See next page

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