ML20107G039
| ML20107G039 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 02/20/1985 |
| From: | Woolever E DUQUESNE LIGHT CO. |
| To: | Knighton G Office of Nuclear Reactor Regulation |
| References | |
| RTR-REGGD-01.122, RTR-REGGD-1.122 2NRC-5-029, 2NRC-5-29, NUDOCS 8502260280 | |
| Download: ML20107G039 (2) | |
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( 12 87 514 Nuclear Construction Division (412) 92M 960 Robinson Plaza. Building 2, Suite 210 Telecopy (412) 787-2629 Pittsburgh, PA 15205 February 20, 1985 United States Nuclear Regulatory Commission Washington, DC 20555 ATTENTION:
Mr. George W. Knighton, Chief Licensing Branch 3 Of fice of Nuclear Reactor Regulation
SUBJECT:
Beaver Valley Power Station - Unit No. 2 Docket No. 50-412 Stress Reconciliation Program use of Code Case N-411 Damping and Regulatory Guide 1.122 Peak Spreading Gentlemen:
For implementation as part of the stress reconciliation program for BVPS-2 Seismic Category I piping, Duquesne Light Company (DLC) r uuests approval to utilize, for select ed cases only, the Code Case N-41i damping values approved by the Pressure Vessel Research Committee (PVRC) and the amplified response spectra (ARS) peak spreading technique of Regulatory Guide 1.122.
Upon approval, the frequency dependent values from Code Case N-411 would be used for generation of the ARS.
These values speci f ic a11y ' are:
5 percent below a frequency of 10 Hz; linear reduct ion from 5 percent to 2 percent between 10 Hz and 20 Hz; and 2 percent above 20 Hz.
These damping values would apply for both one-half SSE and SSE.
The - currently employed damping values are one-half percent and one percent for.the one-half SSE and SSE, respectively.
Upon approval, the ARS peak spreading technique for Regulatory Guide 1.122 would be employed.. -Specifically,. the pe aks -would _be' spread plus and minus 15 percent of the frequency at the peak, and the sides of ~ the resulting envelope would be parallel to those of the peak.
In the currently employed technique, the ARS reak resonant period values are broadened plus 25 percent
,and minus 20 percent with vertical sides.
The use of these higher damping values and the Regulatory Guide 1.122 -
. technique.is expected to preclude the modification of some exiating hardware,
_ to eliminate the need for. the addition of some new hardware, and to ' eliminate the need for some seismic restraints.
The application of the Code Case N-411 ' damping values is consistent
.with' the efforts to reduce the number of seismic restraints.
' Hardwa re reliability and inservice inspection 'and maintenance dif ficulties inherently detract from the safety qualification of these systems in accordance with the findings of NUREC/CR-3718,.
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United States Nuclear Regulatory Commission Mr. George W. Knighton, Chief Page 2 The application of the Regulatory Guide 1.122 peak apread ing technique retains significant safety margin as concluded in NUREG/CR-3526.
Upon your approval of this request, the appropriate revisions will be included in a future FSAR amendment.
Because of the pot ent ially significant impact on engineering and construction activities, your expeditious review of this request would be greatly appreciated.
DUQUESNE LIGHT COMPANY By Y.
E. M. ~Woolever Vice President JJS/wjs cc:
Mr. B. K. Singh, Project Manager Mr. G. Walton, NRC Resident Inspector COMMONWEALTH OF PENNSYLVANIA - )
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COUNTY OF ALLEGHENY
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On this Ja day of
///8, before me, a
for said Commonweabh and County, personally _ appeared Notary Public in and E. J. Woolever, 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, statement s' forth in the Submittel are true -and. correct - to the best of hiEknowledge.
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Notary Public ANITA ELAINE REITER, NOTARY PUSUC ROBINSON TOWNSHIP AltEGHENY COUNTY MY COMMISSION EXPtRES OCTOBER 20,'1986 -
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