ML20029C779
| ML20029C779 | |
| Person / Time | |
|---|---|
| Site: | Oyster Creek |
| Issue date: | 04/19/1994 |
| From: | Keaten R GENERAL PUBLIC UTILITIES CORP. |
| To: | NRC OFFICE OF INFORMATION RESOURCES MANAGEMENT (IRM) |
| References | |
| TASK-03-07.B, TASK-3-7.B, TASK-RR C321-94-2048, NUDOCS 9404290153 | |
| Download: ML20029C779 (2) | |
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GPU Nuclear Corporation
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201-316-7000 TELEX 136-482 Writer's Direct Dial Numbec April 19, 1994 C321-94-2048 U. S. Nuclear Regulatory Commission Att: Document Control Desk Washington, DC 20555 Gentlemen:
Subject:
Oyster Creek Nuclear Generating Station (0CNGS)
Docket 50-219 SEP Topic III-78, Drywell Shield Wa11 Integrity Our letter dated November 19, 1993 transmitted ABB Impell Corporation Report No. 0037-00196-01, Rev.0 which provides calculated stresses in the concrete and reinforcing-bars in the drywell shield wall above elevation 95 ft. The results indicate that stresses are well below allowables.taking into consideration the existing (cracked) condition of the shield wall.
During refueling cutages, the reactor cavity is flooded and the inside surface of the drywell shield wall is exposed to some water due to leakage past the steel plate covering the cavity surface. This water could enter the pre-existing cracks in the concrete wall and wet the surface of the steel reinforcing. However, during normal operation,'very little moisture is present in the vicinity of the drywell shield wall due to the relatively high temperatures and the fact that the cavity is not flooded.
In our recent phone conversation concerning the subject matter, the NRC staff requested GPU Nuclear-to establish a crack monitoring program for the drywell concrete shield wall.to provide confirmatory information regarding shield wall conditions. During the phone conversation, GPU Nuclear informed the NRC staff that a structural systems engineer is assigned to the Oyster Creek site. The systems engineer is responsible for ensuring that the structures at Oyster i
Creek'are monitored and evaluated. The NRC expressed a desire that a formal.
program to monitor. cracks.in. the drywell shield wall be established.
0 9404290153 940419 ADOCK 0500 g9 DR 80012 ceu Nuciear corporation is a subseary or General Public Utdities Corporation
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a C321-94-2048 Page -2 GPU Nuclear agrees to perform the periodic inspections of the drywell shield wall as requested by the NRC staff. Therefore, GPU Nuclear is developing a program to ensure monitoring of concrete conditions during each refueling outage and a formal guideline for performing the monitoring (e.g. visual inspections for crack growth and/or staining of the concrete).
The program and guideline will be in place prior to refueling outage 15R.
Sincerely, R. W. Keaten Director, Technical function
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Adminis'.rator Region I NRC Resident inspector Oyster Creek NRC Pro.iect Manager
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