ML19253C113
| ML19253C113 | |
| Person / Time | |
|---|---|
| Site: | Cooper  |
| Issue date: | 11/05/1979 |
| From: | Seyfrit K NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION IV) |
| To: | Pilant J NEBRASKA PUBLIC POWER DISTRICT |
| References | |
| NUDOCS 7911280504 | |
| Download: ML19253C113 (1) | |
Text
CENTRAL FILES PDR:HQ UNITED STATES 1,,P R
[pn Mo,o, NUCLEAR REGULATORY COMMISSION v
Ub1C REGloN IV 3w G11 fiY AN PLAZA oRIVE, SulTE 1000 E {
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November 5, 1979 Docket No.
50-293 Nebraska Public Power District ATTN:
J. M. Pilant, Director Licensing & Quality Assurance Post Office Box 499 Columbus, Nebraska 68601 Gentlemen:
This IE Information Notice is provided as an early notification of a possibly significant matter.
It is expected that recipients will review the information for possible applicability to their facilities.
No specific action or response is requested at this time.
If further NRC evaluations so indicate, an IE Circular, IE Bulletin, or NRR Generic Letter will be issued to recommend or request specific liccasce actions.
If you have questions regarding the matter, please contact the Director of the appropriate NRC Regional Office.
Sincerely, J
t eg.
Karl V. Seyfrit Director
Enclosures:
1.
IE Information Notice No. 79-26 2.
List of IE Information Notices Issued in the Last Six Months cc:
L. C. Lessor, Superintendent Cooper Nuclear Station Post Office Box 98 Brownville, Nebraska 68321 1443 359 7911280 9 Y
SSINS:
6870 Accession No:
7908220133 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 IE Information Notice No. 79-26 Date:
November 5,1979 Page 1 of 2 BREACH OF CONTAINMENT INTEGRITY Description of Circumstances:
On September 14, 1979, the Consumers Power Company (CPC) notified the NRC of discovery at the Palisades Nuclear Generating Plant of a valve misalignment that had resulted in containment integrity being breached for an indeterminate length of time.
While preparing to perform a Type "C" leak test between two manual valves in a 3" bypass line around the main 48" containment purge valve, plant personnel dis-covered that both of these manual isolation valves were locked in the open posi-tion. These valves should have been locked closed.
Investigation by the licensee indicated that the valves may have been improperly positioned since April, 1978, when an efficiency test of the bypass line filters was performed. The plant has operated at power for the major portion of that time period.
The valve misalignment had no actual impact on the public health. However, in the event of a design basis accident wherein fuel damage and release of primary coolant inside the containment are postulated, the open valves would provide a significant path for a radioactive release from the containment.
The initial design purpose for the bypass system was to provide a long-term hydrogen centro basisaccident.-}jcapability for the containment atmosphere following a design It was intended that after approximately 30 days following an accident, when containment pressure and activity levels dropped sufficiently to permit venting, this system would be manually valved to vent the containment atmosphere, through high efficiency and charcoal filters, to the exhaust stack.
Thus the components in the bypass line beyond the two manual isolation valves were not designed for the severe service they would be exposed to with the valves open during the initial pressure surge of the design basis accident, and signif-icant uncontrolled release would result. High radiation in the vicinity of the bypass line would also make immediate c h even if identified as the source cf ler 7{}
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Current NRC requirements call for Entire doctunent previously control hydrogen buildup.
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