ML20237H080
| ML20237H080 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 08/08/1987 |
| From: | Horn G NEBRASKA PUBLIC POWER DISTRICT |
| To: | Martin R NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| References | |
| CNSS876005, NUDOCS 8708170043 | |
| Download: ML20237H080 (2) | |
Text
L pr N4 - Nebraska Public Power District COOPER NUCLEAR STATION
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August 8, 1987
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I Mr. Robert D. Martin k
d Regional Administrator U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive Suite 1000 Arlington, Texas 76011 l
Dear Mr. Martin:
l This event summary is submitted in accordance with NUREG 0654, Revision 1, Appendix 1 and NPPD Emergency Plan Procedure (EPIP) 5.7.2 to close out the Notification of Unusual Event (NOUE) declared at 0320, August 8, 1987. This NOUE was declared based on Emergency Action Level (EAL) 6.1.1.
This EAL requires that a NOUE be declared whenever a Technical Specification Limiting Condition of Operation (LCO) requires reactor shutdown. The Technical
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Specification LCO exceeded, 3.7.A.3.6, was related to the Pressure Suppression Chamber to Reac'or Building Vacuum Breakers.
t At 0238 on August 8, 1987, during normal power operations, an annunciator was received in the Control Room which indicated that one of the air operated vacuum breakers had moved from the closed position to an intermediate position. Attempts to close the vacuum breaker from the Control Room were unsuccessful and it was declared inoperable.
Shortly thereafter, it was noted by the Control Room operators that pressure suppression chamber pressure was slowly decreasing which indicated an apparent problem with primary containment integrity. A plant shutdown was initiated in accordance with Technical Specification 1.J. and a NOUE was declared, as noted above. Notification to State authorities was completed by 0335 and all other required notifications were completed by 0358.
1 At 0345, it was determined that the slow decrease in pressure was due to a slight leak through the check valve which is in series with the fail open, air operated vacuum breaker. Also, it was discovered that the air operated vacuum breaker was in the intermediate position due to a failed gasket on the air supply filter.
By 0555, repairs were completed, surveillance tests had been satisfactorily completed, and the components were returned to an operable status. Shutdown 8708170043 870000 Q [" D PDR ADOCK 05000298 S
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<...R. D. Martin August 8, 1987 Page 2 was terminated and the NOUE was terminated ac this time. Required notifications were completed at 0601.
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l Div ion Manager of j~
Nuclear Operations 1
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