ML20249B638
| ML20249B638 | |
| Person / Time | |
|---|---|
| Site: | Braidwood  |
| Issue date: | 05/25/1976 |
| From: | Roy G, Thompson D, Warnick F NRC OFFICE OF INSPECTION & ENFORCEMENT (IE) |
| To: | |
| References | |
| PNO-76-091, PNO-76-91, NUDOCS 9806240003 | |
| Download: ML20249B638 (1) | |
Text
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h NhQ U Od PRELIMINARY NOTIFICATION h(
]El1ij May 25, 1976 PRELIMINARY NOTIFICATION OF EVENT OR UNUSUAL OCCURRENCE--PNO-76-91 This preliminary notification constitutes EARLY notice of an event of POSSIBLE safety or public interest significance. The information presented is as initially received without verification or evaluation and is basically all that is known by IE staff on this date.
Facility:
Dresden Unit No. 2 Commonwealth Edison Company
Subject:
FAILURE OF TARGET ROCit RELIEF VALVE TO CLOSE i
At approximately 3:00 a.m. on 5/25/76, the primary coolant Target Rock relief valve failed to close properly after being manually actuated as part of a startup test to verify operability of certain critical compo-nents.
The reactor was in startup phase at approximately 15% power following a lengthy refueling outage. Pressure dropped from 950 psi to 300 psi over a one hour period before the valve rescated. The reactor was manually scrammed after pressure had dropped approximately 125 psi (to 825 psi).
Preliminary information indicates that no safety related problems resulted from the event. Reactor coolant inventory was adequately maintained and the reactor vessel coolant limits and torus water temperature limits were not exceeded.
A Region III (Chicago) inspector is at the site to review corrective action and determination of the cause of failure. No press release is planned at this time and no media interest is expected.
The State of Illinois has been informed of the event.
Regien III received notification of this occurrence by telephone from Dresden Unit No. 2 Operating Engineer at 9:30 a.m. on May 25, 1976.
Contact:
FRWarnick, IE x27261
Chairman Rowden Commissioner Mason S. J. Chilk, SECY Commissioner Gilinsky C. C. Kammerer, CA G. F. Murphy, JCAE i
Commissioner Kennedy L. V. Cossick, EDO E. Volgenau, OIE J. A. Harris, PA B. C. Rusche, NRR J. La Fleur, ISP T. J..NcTiernan, AIA K. R. Chapman, NMSS H. K. Shapar, ELD Transmitted:
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9906240003 760525
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