ML20085F518
| ML20085F518 | |
| Person / Time | |
|---|---|
| Site: | Palisades  |
| Issue date: | 02/04/1975 |
| From: | Sewell R CONSUMERS ENERGY CO. (FORMERLY CONSUMERS POWER CO.) |
| To: | US ATOMIC ENERGY COMMISSION (AEC) |
| Shared Package | |
| ML20085F516 | List: |
| References | |
| AO-2-75, NUDOCS 8308220167 | |
| Download: ML20085F518 (2) | |
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[{/ Power WYgg// Company r ie (?bfi \\IBMjf General Offices: 212 West Michigan Avenue, Jackson, Michigan 49201. Area Code 517 788-0550 February h, 1975 N o e [V k) c ( 1975 - 3 b{ FEB6 a2 I: u:r \\,c p: Docket 50-255 License DPR-20 Division of Reactor Licensing \\,4['k31n.se-($4 Palisades Plant \\ i, 7 US Nuclear Regulatory Commission A0-2-75 Washington, DC 20555 ~ Gentlemen: The Abnormal Occurrence Report A0-2-75 attached describes the waste gas loss while venting the volume control tank. This loss resulted in a small uncontrolled release of radioactive material from the site boundary. Yours very truly, Ralph B. Sewell (Signed) WGF/ map Ralph B. Sewell Nuclear Licensing Administrator CC: JGKeppler, USNRC \\ l i P" 13,..= * /t 3 \\
p p ~ v V w/ ABNORMAL OCCURRENCE REPORT Docket 50-255 1. Report No: A0-2-75 2a. Report Date: February h, 1975 2b. Occurrence Date: January 26, 1975 3 Facility: Palisades Plant, Covert, Michigan h. Identification of Occurrence: Loss of volume control tank gas to the auxiliary building (uncontrolled release of radioactive material from the site boundary). 5 Conditions Prior to Occurrence: Plant in cold shutdown. 6. Description of Occurrence: On January 26, an operator started venting the volume control tank (VCT) to the vaste gas surge tank (WGST). An operator stationed at the gas control panel (C-40) noted that there was no increase in the WGST pressure. At the same time another operator stationed at the evaporator control panel observed a severe vacuum 7g upset. Venting was stopped in order to investigate the problem. t ) 7 Designation of Apparent Cause of Occurrence: Back pressure caused by venting of the VCT blew the loop seal on the evaporator vacuum pump-air water separator. 8. Analysis of Occurrence: The investigation determined that venting of the VCT to the WGST when the evaporator vacuum pump was aligned to discharge into the WGST could cause sufficient back pressure to both upset the operation of the evaporator and blow the loop seal asso-ciated with the evaporator vacuum pump. This allowed gas to escape to the auxiliary building. The amount of gas released from the VCT to the auxiliary building was determined to be 2 7 x 103 liters. The total activity released was 1.06 x 10 6 millicuries. 9 Corrective Action: Procedures will be changed to valve the evaporator I vacuum pump discharge line to the vaste gas collection header prior to venting the VCT. During periods other than venting the VCT, the evaporator vacuum pump discharges will be routed normally to the WGST. i-l 10. Failure Data: NA l [ h v}}