ML19254F681
| ML19254F681 | |
| Person / Time | |
|---|---|
| Site: | Atlantic Nuclear Power Plant  |
| Issue date: | 11/05/1979 |
| From: | James O'Reilly NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION II) |
| To: | Collier A OFFSHORE POWER SYSTEMS (SUBS. OF WESTINGHOUSE ELECTRI |
| References | |
| NUDOCS 7911160384 | |
| Download: ML19254F681 (5) | |
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UNITED STATES 1
0 NUCLEAR REGULATORY COMMISSION o
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REGION 11 k
E 101 MARL!TTA ST., N.W., SUITE 3100 o
ATLANTA, GEORGIA 30303 NOV 5 1979 In Reply Refer To:
RII:JP0 50-437 Offshore Power Systems
' Attn:
A. R. Collier, President P. O. Box 8000 Jacksonville, Florida 32211 Gentlemen:
This Information Notice is provided as an early notification of a possibly significant matter.
It for possible applicability to their facilities.is expected that recipients will review the in is requested at this time.
No specific action or response Bulletin, or NRR Generic Letter will be issued to recommend or requ licensee actions.
the Director of the appropriate h7C Regional Office.If you have questions rega Sincerely, Y- -tw James P. O'Reill' Director
Enclosures:
1.
IE Infomation Notice No. 79-26 2.
List of IE Information Notices Issued in the Last Six Months 1351 291 3?M rggT1160
SSINS:
6870 Accession No:
7908220133 UNITED STATES NUCLEAR REGULATORY COMMISSION OFFICE OF INSPECTION AND ENFORCEMENT WASHINGTON, D. C.
20555 November 5, 1979 IE Information Notice No. 79-26 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 hydrogencontrohcapabilityforthecontainmentatmospherefollowingadesign basis accident.- It was intended that after approximately 30 days following an accident, when contai. ament pressure and activity levels dropped sufficiently to permit venting, this system would be manually valved to vent the containment atmosphere, thromh 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 e ~
open during the initial pressure surge of the design basis accident, and signif-icant uncontrolled release would result. High radiation in ths vicinity of the bypass line would also make immediate closing of the manual isolation valves, even if identified as the source of leaka n. an avt 1 - '--- '-
The principal cause for this event was proper use and positioning of these val' DUPLICATE DOCUMENT valve line-up checklist, which is perfo:
Entire document previously If Current NRC requirements call for tl entered into system under:
hydrogen buildup. Palisades has recombi ANO 4
1351 292 no-of Pa"":