ML19254F604
| ML19254F604 | |
| Person / Time | |
|---|---|
| Site: | Beaver Valley |
| Issue date: | 11/05/1979 |
| From: | Grier B NRC OFFICE OF INSPECTION & ENFORCEMENT (IE REGION I) |
| To: | Dunn C DUQUESNE LIGHT CO. |
| References | |
| NUDOCS 7911160035 | |
| Download: ML19254F604 (1) | |
Text
{{#Wiki_filter:h . pn nic o d o UNITED STATES [ Y, f.( ( j NUCLEAR REGULATORY COMMISSION ,.41 ',.(/, E REGION I 3, ', IN [ U g 631 PARK AVENUE %, ' N # " o KING oF PRUSSIA, PENNSYLVANIA 19406 +.... Docket No. 50-334 Nuo U u als Duquesne Light Company ATTN: Mr. C. N. Dunn Vice President Operations Division 435 Sixth Avenue Pittsburgh, Pennsylvania 15219 Gentlemen: This Information Notice is provided as an early notification of a possible 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, Bulletin, or NRR Generic Letter will be issued to recommend or request specific licensee actions. If you have any questions regarding the matter, please contact this office. Sincerely, s o n Boyce H. Grier p Director
Enclosures:
1. IE Information Notice No. 79-26 2. List of IE Information Notices Issued in the Last Six Months CONTACT: D. L. Caphton (215-337-1266) cc w/encls: F. Bissert, Technical Assistant Nuclear R. Washabaugh, QA Manager J. Werling, Station Superintendent G. Moore, General Superintendent, Power Stations Department J. J. Carey, Nuclear Technical Assistant R. Martin, Nuclear Engineer 1351 320 h 7 911100 O N
ENCLOSURE 1 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 discovered that both of these manual isolation valves were locked in the open position. 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 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 significant uncontrolled release would result. High radiation in the vicinity of the bypass line would also isolation valves, even if identified as hazardous operation. DUPLICATE DOCUMENT TM principal cause for this event wis prtper use and positioning of these val Entire document previously valve line up checklist, which is perfo entered into system under: lb 2 NO A 1/ Current NRC requirements call for t 9/ control hydrogen buildup. Palisades ha No. of pages: ef W}}