ML20149D482

Final Deficiency Rept CP-88-26 Re Potential for Failure of Turbine Bldg During Seismic Event.Initially Reported on 880129.Detailed Mods Being Finalized Based on as-built Data Collected During Post Const Hardware Validation Program

ML20149D482
Person / Time
Site:	Comanche Peak
Issue date:	02/04/1988
From:	Beck J TEXAS UTILITIES ELECTRIC CO. (TU ELECTRIC)
To:	NRC OFFICE OF ADMINISTRATION & RESOURCES MANAGEMENT (ARM)
References
CP-88-26, TXX-88194, NUDOCS 8802090513
Download: ML20149D482 (2)

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wmi.m c. coumii February 4,1988 Execusht Hce Presider,t U. S. Nuclear Regulatory Commission Attn: Document Control Desk Washington, D.C. 20555

SUBJECT:

COMANCHE PEAK STEAM ELECTRIC STATION DOCKET NOS. 50-445 AND 50-446 TURBINE BUILDING DESIGN REQVIREMENTS SDAR: CP-88-26 (FINAL REPORT)

Gentlemen:

On January 29, 1988, we verba'sy notified your Mr. R. F. Warnick of a deficiency involving the potential for a failure of the Turbine Building during a seismic event, which we are conservatively reporting under 10CFR50.55(e). The required information follows.

DESCRIPTION During the design validation of the Turbine Building, it was determined that the existing structural steel bracing system was not designed with sufficient margin to preclude failure under seismic or tornado loads.

This deficiency is the result of an apparent failure to implement design criteria as specified in the FSAR for the Turbine Building. Specifically, provisions for seismic / tornado interactions with adjoining seismic Category I structures were not considered.

This deficiency could result in unacceptable interactions between the Turbine Building and adjacent seismic Category I structures.

SAFETY IMPLICATIONS During a seismic or tornado event, the failure of the Turbine Building could result in impact to the adjacent Seismic Category I structures. Had this condition remained uncorrected it could have adversely affected the safety of operations. In consideration of the effort required to evaluate the adequacy of the adjacent Category I structure, this issue has been conservatively identified as reportable under the provisions of 10CFR50.55(e).

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TXX-88194 February 4,~1988 Page 2 of 2 CORRECTIVE ACTIONS We:have completed calculations which demonstrate that the turbine building structural steel frame recuires modification so that failure of the building during a seismic or tornaco event would not impact the adjacent seismic Category I structures. Detailed modifications are being finalized based on as-built data collected during Post Construction Hardware Validation Program (PCHVP) in accordance with the Field Verification Methods (FVMs) CPE-SWEC-FVM-EE/ME/IC/CS-089, "PCHVP~ Engineering Walkdowns" and CPE-SWEC-FVM-EE/ME/IC/CS-090," PCHVP Quality Control Reinspections."

.The modifications will be implemented according to the completion schedule for the PCHVP in Unit I and the general. construction schedule for Unit 2.

Very truly yours, W. G. Counsil By:

JohW W. Beck Vice President, Nuclear Engineering CBC/grr c-Mr. R. D. Martin, Region IV Resident inspectors, CPSES (3) i h

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