ML19296D165

RO 80-08/01T:on 800225,during Cable Tray & Conduit as-built Configuration Review,Preliminary Framing Beam Analysis Indicated Potential Floor Beam Overstress.Caused by Conduit & Tray Support Horizontal Acceleration

ML19296D165
Person / Time
Site:	Beaver Valley
Issue date:	02/25/1980
From:	Werling J DUQUESNE LIGHT CO.
To:
References
BVPS:JAW:797, NUDOCS 8002290426
Download: ML19296D165 (2)

Text

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Duquesne Ugat ,m, -

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7[# " DUQUESNE LICllT COMPANY Beaver Valley Power Scation Post Office Box 4 Shippingport, PA 15077 February 25, 1980 BVPS: JAW:797 Beaver Valley Power Station, Unit No. 1 Docket No. 50-334, License No. DPR-66 LER 80-08/01T Mr. B.11. Crier, Director of Regulation United States Nuclear Regulatory Commission Region 1 631 Park Avenue King of Prussia, Pennsylvania 19406

Dear Mr. Crier:

In accordance with Technical Specification 6.9.1.8.1, the following was reported to NRC Site Inspector D. A. Beckman at 1100 hours0.0127 days <br />0.306 hours <br />0.00182 weeks <br />4.1855e-4 months <br />, Ecbruary 25, 1980.

Duquesne Light Company has been notified by the BVPS architect / engineer that, based on in-plant inspections, a review was conducted of the as-built configuration of cable trays and conduits that are attached to the underside of the cabic spreading floor at elevation 725 ft. Because of the light design of the floor slab, a preliminary analysis of the framing beams (using conservative values of acceleration for the DBE conditions) has indicated a potential overstress in the floor beams. The overstress is due, primarily, to the horizontal acceleration of the conduit and tray supports on the lower flange of the steel beams. The floor support system has been checked for the normal dead load, live load and vertical carthquake components and has been determined satisfactory. It is the imposition of the lateral earthquake lo. ids which causes beam local overstress.

Due to dif ficulties encountered in modeling the geometry of the cable tray conduits and their supports, we are establishing a conservative design criteria and we are proceeding with modifications, rather than attempting further analysis. We anticipate this work can be completed prior to plant start-up.

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Mr. B. H. Crier -

February 25, 1980 BVPS: JAW: 797 Page 2 We believe this problem is limited to the cable spreading floor since no other safety-related area of the plant has this configuration of light framing beams with similar inposed loading from conduits and cable trays.

Since the plant is shutdown due to the refueling outage and certain functions are still continuing, we considered it necessary to check the adequacy of the steel beams for the ODE conditions. For this analysis, the peak acceleration values from the Amplified Response Spectra based on Soil Structure Interaction and 1/27. damping values were used. In this analysis, a live load of 20 p.s.f. was used and torsional effects due to horizontal forces on the lower beam flange were ignored.

Based on this evaluation, it is our judgement that although the beams are slightly overstressed, in the event of a credible earthquake, this condition would not preclude maintaining the plant in its present shutdown condition.

Very truly yours, 4

's r J. A. Werling Superintendent cc: Director Of Management & Program Analysis United States Nuclear Regulatory Commission Washington, D. C. 20555 D. L. Wigginton, BVPS Licensing Project Managerw/'

United States Nuclear Regulatory Commission Washington, D. C. 20555 D. A. Beckman, Ntelear Regulatory Commission, King of Prussia, PA C. A. Olson, Secretary, Prime Movers Committee - EEI  ;

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