ML20010B210
| ML20010B210 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 08/05/1981 |
| From: | Carey J DETROIT EDISON CO., DUQUESNE LIGHT CO. |
| To: | Varga S Office of Nuclear Reactor Regulation |
| References | |
| GL-81-14, TAC-43646, NUDOCS 8108140218 | |
| Download: ML20010B210 (3) | |
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. August 5, 1981 15219 Director of Nuclear Reactor Regulation
, United States Nuclear Regulatory Commission Attn:
Mr. Steven A. Varga, Chief Operating Reactors Branch No. 1 Division of Licensing Washington, DC 20555
Reference:
Beaver Valley Power' Station, Unit No. 1 Docket No. 50-334 Seismic Qualification of Auxiliary Feedwater Systems - Generic Letter 81-14 Gentlemen:
In response to your letter of February 10, 1981, we are providing the following information concerning the seismic design of the Auxiliary Feedwater System (AFS) at Beaver Valley Power Station Unit No.1.
The AFS has been designed, constructed, and maintained to withstand a Safe Shutdown Earthquake (SSE) utilizing analytical, testing, evaluation methods and accentance criteria consistent with other saferv grade systems in the station.
The AFS was within the scope and considered in une reviews conducted to satisfy the requirements of I.E.Bulletins 79-02, 79-04, 79-07, 79-14, 80-11, and I.E.
The AFS piping was reanalyzed as part of the effort to satisfy the NRC Order to Show Cause dated March 13, 1979. The seismic reanalysis was performed using the NUPIPE-SW computer analysis program. The NUPIPE-SW code utilizes modal response combinations as follows:
Intermodal - Square Root Sum of the Squares (SRSS) grouping method for modal combination between modes, where closely spaced modes are combined by absolute sum.
Intramodal - SRSS for combination of earthquake directional effects within the mode.
Piping was analyzed utilizing amplified response spectra (ARS) that were developed using soil structure interaction techniques (SSI-ARS). The resultant stresses and loads were used to evaluate piping, supports, equipment nozzles, penetrations and equipment supports. Acceptance criteria was based on allowable stresses contained in B31.1.
The analysis methods are explained in more detail in the " Report on the Reanalysis cf Safety Related Piping Systems for Beaver Valley Unit No. 1".
The report and subsequent revision were submitted in our letters dated June 29, 1981, July 11, 19'i3, July 18, 1979, July 27, 1979, August 8, 1979, and August 11, 1980.
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Beaver Valley Power Station, Unit No.1 Docket No. 50-334 Seismic Qualification of Auxiliary Feedwater Systems - Generic Letter 81-14 Page 2 The AFS pumps seismic calculations have been reviewed and determined to be seismically qualified to the criteria specified in the Beaver Valley Power Station FSAR.
The remaining equipment was qualified either-by test or engineering evaluations to the appropriate seismic Criteria specified in FSAR.
The installation of electrical equipment was'in accordance with standard specification that met the seismic criteria contained in the FSAR. The specification provided the required support type and spacing to meet seismic qualification.
The distances were developed by calculating the first mode fundamental natural frequency of the supported system and then comparing it to the DBE amplified response spectra curves for the area wheru the equipment was to be installed. The ARS curves were peak spread i 15% to establish an exclusion band for supported system frequencies. The completed support systems were reviewed in the field to confirm conformance with installation 4
specifications, and all descrepancies were either corrected or determined
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to be acceptable by analysis.
Very truly yours, 1
J. J. Carey Vice President, Nuclear cc:
Mr. D. A. Beckman, Resident Inspector-j U.S. Nuclear Regulatory Commiscion Beaver Valley Power Station Shippingport, PA 15077 U.S. Nuclear Regulatory Commission c/o Document Management Branch Washington, DC 20555 f
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j COMMONWEALTH OF PENNSYLVANIA)
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COUNTY OF BEAVER
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, before me, id (Zebwe, a Notary P%lic in and for said Commonwealth an County, personally appe(red J. J. Carey, who being duly sworn, deposed, and said that (1) he is Vice President of Duquesne Light, (2) he is duly authorized to execute and file the foregoing Submittal on behalf of said Company, and (3) the statements set forth in the Submittal are true and correct to the best of his knowledge, information and belief.
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JLD.TH D. ANTHONY, Notary PutF M pp:ngori daros<,h, Beaver Co., Pa.
My Commiss;on Eepires Dec. 12, 1983 l
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