ML19319D997
| ML19319D997 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 04/08/1975 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| References | |
| NUDOCS 8003270708 | |
| Download: ML19319D997 (2) | |
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SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 S Street. Box 15830. Sacramento, California 95813; (916) 452 3211 April 8, 1975
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Director e
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Directorate of Licensing
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U. S. Nuclear Regulatory Consnission
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Washington, D. C.
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sV Docket No. 50-312 Wg /.,; 3, V Unusual Event 75-1
Dear Sir:
As defined by Technical Specifications " Appendix B",
Section 5.6.2.C, we are reporting the following Unusual Event as A0-75-1.
During normal operation at Rancho Seco chlorine is injected into the Circulation Water System to control algae. The additions are at high concen-tration to " shock" the organisms affixed to the turbine condenser and increase the total circulating water system to approximately 1.0 ppm chlorine. The I
m programmed injection starts twice a day at 0900 and 2100 and terminates at
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1010 nna m n.
Tha aan,nanca i nvni sra. 1/? hone injoerinn inen the anisch con-d denser, 1/2 hour into the Plant Cooling Water System (part of the Circulating Water System), and 1/2 hour into the norch condenser. When the system is operating at power the chlorine is amoved from the warm water when sprayed through the cooling towers.
On March 22, 1975, the reactor was shutdown-but the Circulating Water System was continued in operation until the next day. The system was shutdown the morning of March 23 just after the chlorine injec. tion. With the Circulating Water Pumps secured the tower sprays caused a temporary overflow condition.
Effluent samples taken after overflow were a maximum of 1.5 ppm chlorine. The chlorine decreased to within the Technical Specification " Appendix B",
Section 2.2 limit within two hours.
a Two conditions will be initiated to prevent reoccurrence of this event:
- 1) A change to the operating procedure will be made to require,
a chlorine sample during no mal shutdown of the circulating water system. The sample must be less than the T. S. limit prior to securing all the Circulating Water Pumps.
- 2) The intent of the Technical Specifications is to use an average of the daily samples analyzed. This method is used for the California Regional Water Quality Control Board and will be the basis for future reporting requirements.
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@PY SENT REGION 'I A tt ELECTRIC SYSTEM S E RVIN G MORE THAN 600,000 IN THE^ HEART OF fA L I F O R N I A
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E Director Directorate of Licensing April 8, 1975 r
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4 We feel if the above conditions are put into effect the safety of the environment will be assured and a reoccurrence of this event will be prevented.
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Respectfully l
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. J. Mattimoe
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Assistant Ceneral Manager and Chief Engineer t
R. H. Engelken, Region V 1
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