ML20077L518
| ML20077L518 | |
| Person / Time | |
|---|---|
| Site: | Limerick  |
| Issue date: | 08/05/1983 |
| From: | Bradley E PECO ENERGY CO., (FORMERLY PHILADELPHIA ELECTRIC |
| To: | Schwencer A Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8308090460 | |
| Download: ML20077L518 (3) | |
Text
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PHILADELPHIA ELECTRIC COMPANY 2301 M ARKET STREET P.O. BOX 8699 PHILADELPHI A. PA.19101 EDW ARD G. B AUER, J R.
1215)841-4000 oesas AL coWNSEk EUGENE J. BR ADLEY
)
assoceava samenAL C.WeeSEb DON ALD BLANKEN RUDOLPH A. CHILLEMI E. C. MI R K H A LL T. H. M AH ER CORN ELL cAUi. AUERB AC" h ut 5 MM 8
.S.............m.
EDW ARD J. CULLEN. JR.
THOM AS H. MILLER. JR.
tREN E A. McMEN N A AssesTANT C.WNSEb Mr.
A.
Schwencer, Chief Licensing Branch No. 2 Division of Licensing U.
S.
Nuclear Regulatory Commission Washington, D.C.
20555
Subject:
Limerick Generating Station, Units I & 2 Structural and Geotechnical Engineering Branch (SGEB) Open Item Re ference :
Telephone Conference between NRC SGEB Reviewer and Philadelphia Electric Company on August 3, 1983 File:
GOVT l-1 (NRC)
Dear Mr. Schwencer:
The attachment provides information requested by the Structural and Geotechnical Branch Reviewer during the referenced telecon.
Sincerely, I,
i Eugen J
Brad ey JTR/gra/72 Attachment Copy to:
See Attached Service List I
8300090460 830805 PDR ADOCK 05000352 A
- s. '.
o cc: Judge Lawrence Brenner (w/ enclosure)
Judge Richard F. Cole (w/ enclosure)
Judge Peter A. Morris (w/ enclosure)
Troy B. Conner, Jr., Esq.
(w/ enclosure)
Ann P. Hodgdon (w/ enclosure)
Mr. Frank R. Romano (w/ enclosure)
Mr. Robert L. Anthony (w/ enclosure)
Mr. Marvin I. Lewis (w/ enclosure)
Judith A. Dorsey, Esq.
(w/ enclosure)
Charles W. Elliott, Esq.
(w/ enclosure)
Jacqueline I. Ruttenberg (w/ enclosure)
Thomas Y. Au, Esq.
(w/ enclosure)
Mr. Thomas Gerusky (w/ enclosure)
Director, Pennsylvania Emergency Management Agency (w/erclosure)
Mr. Steven P. Hershey (w/ enclosure)
Donald S. Bronstein, Esq.
(w/ enclosure)
Mr. Joseph H. White, III (w/ enclosure)
David Wersan, Esq.
(w/ enclosure)
Robert J. Sugarman, Esq.
(w/ enclosure)
Martha W. Bush, Esq.
(w/ enclosure)
Spence W. Perry, Esq.
(w/ enclosure)
Atomic Safety and Licensing Appeal Board (w/ enclosure)
Atomic Safety and Licensing Board Panel (w/ enclosure)
Docket and Service Section (w/ enclosure)
.+,--m
0-4 Supplemental Information on Cable Tray Damping Values The-following discussion supplements the discussion o f Electrical Raceway' Damping Valves transmitted'via letter from J.
S.
Kemper to A.
Schwencer; dated-July 27, 1983 and provides additional justification for the.use of a 10% damping valfe for cable tray systems:
- I.
Bechtel-Power Corporation test results (FSAR: Re fe rence 3.7-7) show that cable tray damping values of up to 50% o f critical were - experienced.
Based on those test results, the referenced report' recommended using a conservative damping value of 20%.
Since Limerick used a valve of only 10%, a considerable margin of reserve stress-capacity exists between the stresses whichfwould. result using the damping values determined by the test program and the stresses'when the 10%'value actually.used in.the Limerick stress analysis is employed.
2.
Additional margin exists in the design of the cable tray supports. -Based on.a random sample of cable tray supports, conservatively assuming peak accelerations, fully loaded tray and using. enveloping response spectra, 95% of the cable tray-supports have greater than 5% stress margin.
'It should be noted that most cable trays as installed at L'imerick are not fully loaded.
In addition, standard LGS cable tray supports are designed-using enveloping response spectra which represent a worst case for all Class I' structures.
Therefore, supports installed in any but the few critical enveloping building locations have an additional 1ayer of conservation because they have been designed for accelerations substantially higher
.than those calculated for their locations.
'3.
Based on-the above discussion, even if a 7% damping value were used for s reanalysis, very f ew o f the existing cable tray supports.would have the potential for exceeding their design allowables.
Since~in these few cases there would be a redistribution of loads to other members, no cable tray supports /would be expected to be unable to continue to perform a' support function.
'JTR/gra/73
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