ML20198J257
| ML20198J257 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 05/23/1986 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Zwolinski J Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20198J261 | List: |
| References | |
| 5512-86-102, NUDOCS 8606030038 | |
| Download: ML20198J257 (2) | |
Text
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GPU Nuclear NUCIMF 100 interpace Parkway Parsippany New Jersey 07054 201 263-6500 TELEX 136-482 Writer's Direct Dial Number:
May 23, 1986 5512-86-102 Mr. John A. Zwolinski, Chief Operating Reactors Branch tb. 5 Division of Licensing U.S. foclear Regulatory Commission Washington, DC 20555
Dear Mr. Zwolinski:
Subject:
Oyster Creek foclear Generating Station Docket to. 50-219 Mark I Containment Torus-to-Drywell Vacuum Breakers
Reference:
(1) GPU fbclear letter dated August 14, 1985 from P.B. Fielder (GPUN) to J. A. Zwolinski (NRC)
(2) C.D.I. Tech ibte fb. 84-23, Revision 1, December 1985,
" Mark I Wetwell To Drywell Differential Pressure Load and Vacuum Breaker Response for the Oyster Creek Nuclear Power Plant thit 1" (3) NRC letter dated December 24, 1984 from D.B. Vasallo (hRC) to H.C. Pfefferlen (GE).
(4) C.D.I. Tech Note to. 84-23, Revision 0, January 198S,
" Mark I Wetwell lo Drywell Differential Pressure Load and Vacuum Breaker Response for the Oyster Creek foclear Power Plant Unit 1" In accordance with Reference 1, this letter provides the status of the analysis of the Oyster Creek Tours-to-Drywell vacuum breaker valves for the limiting load combination, which includes the chugging, slamming transient defined in the latest General Electric Mark I Program load definition and all other concurrent Mark I Program loads.
Continuum Dynamics Inc. has performed a modified analysis, Reference 2, removing the excess conservatism identified in Reference 3.
This analysis indicated that certain vacuum breaker valve parts could still become overstressed (i.e., the counterweight hubs and couterweight arm hub keys)during a chugging, slaming transient.
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GPU Nuclear is a part of the General Pubhc Utilities System
John A. Zwolinski Page 2 5512-86-102 As modification of valve parts is still required, GPUN will replace all the valve parts previously identified in Reference 1 (couterweight arms, disk arms, disk arm keys, valve shaft, couterweight hubs and couterweight arm hub keys).
The replacement of valve parts will be made with parts having different material properties in order to achieve acceptable stress levels.
Upon completion of these modifications the vacuum breaker valves will conform to the analysis contained in Reference (4), attached.
GPUN requests deferment of any modification work on these valves until the Cycle 12 refueling outage (12R), when seven of the fourteen valves would be modified. Completion of the work on the remaining seven valves would be during the Cycle 13 refueling outage (13R).
Very truly yours, NA>
ggg - Lj Vice President and Director Oyster Creek PBF/ jap /09691/15 Attachment cc:
Dr. Thomas E. Murley, Mministrator Region I U.S. foclear Regulatory Commission 631 Park Avenue King of Prussia, PA 19406 Mr. Jack N. Donohew, Jr.
U.S. Nuclear Regulatory Commission 7920 Norfolk Avenue, Phillips Bldg.
Bethesda, MD 20014 Mail Stop tb. 314 hRC Resident Inspector Oyster Creek Nuclear Generating Station J