ML20093M371
| ML20093M371 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 10/16/1984 |
| From: | Fiedler P GENERAL PUBLIC UTILITIES CORP. |
| To: | Crutchfield D Office of Nuclear Reactor Regulation |
| Shared Package | |
| ML20093M374 | List: |
| References | |
| TASK-03-05.B, TASK-3-5.B, TASK-RR NUDOCS 8410220093 | |
| Download: ML20093M371 (2) | |
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GPU Nuclear Corporation Nuclear
- == 388 Forked River, New Jersey 08731-0388 609 971-4000 Writer's Direct Dial Number:
October 16, 1984 Mr. Dennis M. Crutchfield, Chief Operating Reactors Branch #5 Division of Licensing U.S. Nuclear Regulatory Commission Washington, D. C.
20555
Dear Hr. Crutchfield:
Subject:
Oyster Creek Nuclear Generating Station Docket No. 50-219 SEP Topic III-5B Pipe Break Outside Containment The Oyster Creek isolation condenser steam lines have two automatic isolation valves outside and adjacent to the drywell. A break between these valves with a failure of the first isolation valve, or a break between the second valve and the condenser resulting in pipe whip such that the isolation valves would not close, would both result in a LOCA outside containment. The physical arrangement and space availability preclude installation of restraints or an isolation valve inside the drywell.
GPU Nuclear has submitted a fracture mechanics analysis which demonstrates that through-wall cracks in the isolation condenser supply and return piping would remain stable under severe pipe pressure loading and rotational stresses. An instantaneous pipe break would not occur.
During the integrated assessment of the subject topic, GPU Nuclear agreed to perform an analysis to determine a proper leak detection method for the emergency condenser lines. The attached report describes the analysis performed and is entitled " Crack Growth and Leak Rate Assessment of the Oyster Creek Emergency Condenser System Piping Outside Containment Below the 95 foot Elevation. "
The results of the analysis show that leak rates from postulated cracks are sufficiently high enough to use visual monitoring as an acceptable method of leak detection. Additionally, sufficient time exists to take appropriate actions (i.e., shutdown or isolate the affected condenser) between the time of leak detection and the time that a crack would grow to an unstable length.
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The Oyster Creek Technical Specification will be revised, following the receipt of an SER on this topic, to require a visual surveillance of the supply and return lines of the Emergency Condenser System once csery twenty-four (24) hours.
Very truly yours, Vice President and Director Oyster Creek 1r/0409e cc: Administrator Region I U.S. Nuclear Regulatory Commission 631 Park Avenue King of Prussia, Pa. 19406 NRC Resident Inspector Oyster Creek Nuclear Generating Station Forked River, N. J.
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