ML19341C232
| ML19341C232 | |
| Person / Time | |
|---|---|
| Site: | Summer  |
| Issue date: | 02/25/1981 |
| From: | Nichols T SOUTH CAROLINA ELECTRIC & GAS CO. |
| To: | Harold Denton Office of Nuclear Reactor Regulation |
| References | |
| NUDOCS 8103020461 | |
| Download: ML19341C232 (1) | |
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SourH CARollNA ELECTRIC a gas COMPANY
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CotuMeiA. south CAROLINA 29218 w,,[,I.5.S*J.sa.-
Feb uary 25, 1981
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Mr. Harold R. Denton, Director Office of Nuclear Reactor Regulation U. S. Nuclear Regulatory Commission Washington, D. C.
20555
Subject:
Virgil C. Summer Nuclear Station Docket No. 50/395 Postulated Valve Missiles
Dear Mr. Denton:
As discussed with Mr. Jared Wermiel of the Auxiliary Systems Branch, South Carolina Electric and Gas Company (SCE&G) acting for itself and agent for the South Carolina Public Service Authority, provides forty-five (45) copics of a marked up page in Chapter 3.5 of the FSAR which discusses valves acting as missiles outside the reactor building. This page will be included in FSAR Amendment 24 to be issued on March 2, 1981.
If you have any questions, please let us know.
Very truly yours, R
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T. C. Nichols, Jr.
RBC:TC:1:glb Euclosure cc:
V. C. Summer w/o enclosure H. N. Cyrus G. H. Fischer w/o enclosure J. B. Knotts, Jr.
T. C. Nichols, Jr. w/o enclosure J. L. Skolds C. A. Price B. A. Bursey D. A. Nauman O. S. Bradham W. A. Williams, Jr.
ISEG R. B. Clary PRS A. R. Koon NPCF/Whitaker A. A. Smith File v>
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m Valves with threaded stces and backseats are not postulated as potential missile sources because of the unlikelihood of coincidant failure of both
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the threaded stem and the backseat.
Valve bonnets are not postulated as potential missile sources when the allowable stress for bonnet r e t a.'..! n g ring material is less than 20 percent of the material yield strength.
Bolted valve bonnets are not postulated as missiles when the safety factor for the bolting is greater than 4.
Valves outside containment were reviewed and none were postulated as missiles.
1L4 (The main feedwater check valve bonnets were previously postulated as missiles.
These valves were replaced, because of feedwater
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water hammer concerns, with those of another design which meets s
the criteria described above.)
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Li 3.5-2 AMENDMENT H 1981 ti a re k,