ML19254F670
| ML19254F670 | |
| Person / Time | |
|---|---|
| Site: | Davis Besse  |
| Issue date: | 11/05/1979 |
| From: | James Keppler NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION III) |
| To: | Crouse R TOLEDO EDISON CO. |
| References | |
| NUDOCS 7911160234 | |
| Download: ML19254F670 (1) | |
Text
{{#Wiki_filter:[pa arog o UNITED STATES [ l'~ NUCLEAR REGULATORY COMMISSION .r. g a e REGION 111 I' f 799 ROOSEVELT ROAD o,, U %.'.%./ o GLEN ELLYN. ILLINOIS 60137 Docket No. 50-346 3g79 Toledo Edison Company ATTN: Mr. Richard P. Crouse ,/ Vice President Energy Supply Edison Plaza [ 300 Madison Avenue Toledo, OH 43652 /l / Gentlemen: / ,f t - .t This Information Notice is provided as an early notification of a possibly significant matter. It is expected that recipients will review the infoy-mation for possible applice ity to their facilities. No specific actb y or response is requested at this time. If further NRC evaluaticns so j'igT-cate, an IE Circular, Bulletin, or NRR Generic Letter will be isnue d S recommend cr request specific licensee actions. If you have quer,tiu9 regardingthemater,pleasecontacttheDirectoroftheappropribt<b.#C Regional Office. il/; h55 Sincerely, @g,i t JJames G. Ke % de~/.b yh2 A ppler fk Director $i 4!3
Enclosure:
IE Information ( pj Notice No. 79-26 "p @lI cc w/ encl: Mr. T. Murray, Station Superintendent Central Files Director, NRR/DPM Director, NRR/ DOR PDR Local PDR NSIC TIC Esrold W. Kohn, Power Siting Commission 4[.537 Helen W. Evans, State of Ohio 7011160 2 3
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 containmert 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 contro basisaccident.-{capabilityforthecontainmentatmospherefollowingadesign 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 componer.ts 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 closing of the manual isolation valves, even if identified as the source of leakage, an extremely hazardous operation. The principal cause for this event was inadequacy of the procedures addressing proper use and positioning of these va' valve line up checklist, which is perf( DUPLICATE DOCUMENT 1/ Current NRC requirements call for 1 hydrogen buildup. Palisades has recomt Entire document previously entered into system under: ANO [ g v-r- No. of pages: M I}}