ML19317G117
| ML19317G117 | |
| Person / Time | |
|---|---|
| Site: | Rancho Seco |
| Issue date: | 01/18/1978 |
| From: | Mattimoe J SACRAMENTO MUNICIPAL UTILITY DISTRICT |
| To: | |
| Shared Package | |
| ML19317G118 | List: |
| References | |
| RJR-78-41, NUDOCS 8002210805 | |
| Download: ML19317G117 (2) | |
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\\E R g COPY g (Vhr SMUD SACRAMENTO MUNICIPAL UTILITY DISTRICT C 6201 S Street, Box 15830. Sacramento, California 95813; (916) 452 3211 RJR 78-41 January 18, 1978 I <
p.f Director of Regulatory Operations
.2 Attention:
Mr. R. H. Engelken
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NRC Operations Office, Region V 1990 North California Boulevard
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^*',T Walnut Creek Plaza, Suite 202 Walnut Creek, California 94596 Re: Operating License DPR-54
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Docket No. 50-312 Unusual Event 78-1
Dear Mr. Engelkut:
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In accordance with Technical Specifications for Rancho Seco Nuclear Generating Station, Appendix B, Section 5.6.2C, the Sacramento Municipal Utility District
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hereoy submits the following written report concerning Unusual Event 78-1.
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,m('jj Plant water discharge pH limits are established by Technical Specifications, Ap-
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s pendix B, Section 2.4 at 6.5 mf * "m and 8.5 maximum. This section allows excep-tions to these limits as permitted by the California Regional Water Quality Control Board (CRWQCB). The plant makeup water source is Folsom South Canal, which exhibits cyclical levels of pH ths.t range well above the upper limit during the summer months. To accommodate this characteristic of the makeup water, the CRWQCB permits plant releases to have pH levels as high as the pH level of Folsom South Canal if that level exceeds 8.5 (CRWQCB Order No.76-170). As reported in a telephone conversation of January 9, 1978, these limits were exceeded on several occasions in December 1977 and January 1978.
The cause of these out of specification releases was the setpoint of the switch which provides for automatic diversion of the eff1 sent when the allowable pH range is exceeded. In response to raising pH levels during the summer, the switch setpoint was changed from 8.5 to 9.1 as permitted by the CRWQCB order. However, when the pH levels of w e canal dropped with the onset of winter, the resetting of the switch back to 8.5 was overlooked. As a result, on the following dates the 7-~
pH of the plant effluent exceeded the limit in effect (8.5) without diversion:
-l Date g
Period
-I December 6 8.8 less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> December 16 9.0 less than 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> December 27 8.6 1 hour1.157407e-5 days <br />2.777778e-4 hours <br />1.653439e-6 weeks <br />3.805e-7 months <br /> December 31 9.1 7 hours8.101852e-5 days <br />0.00194 hours <br />1.157407e-5 weeks <br />2.6635e-6 months <br /> January 1 9.0 9 hours1.041667e-4 days <br />0.0025 hours <br />1.488095e-5 weeks <br />3.4245e-6 months <br /> Q,).
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k Director of Regulatory vperations 7,
Attention : Mr. R. H. Engelken-NRC Operations Of fic, Region V
' Walnut Creek, Ca" '
aa 94596 January 18, 1978.
Page Two I
The telephone report also listed the limit as being exceeded on January 1 for three hours. During this period the effluent pH was 9.4, high enough to trip the switch and divert the effluent. After diversion, the water collects in re-
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tantion basins where it is treated to bring it within specifications prior to release.
To prevent recurrence of this type of event, the log sheet on whien the chemistry technicians record Folsom South Canal pH levels will be modified to specify 8.5 as an action level. If the pH is found to drop below 8.5, direction will be gypen to have the diversion switch setpoint lowered to 8.5.
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The Chemistry-Radiation Supervidor will continue to review the log sheets for de-viation from specifications.
Respec y submitted,
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4M J. J. Mattimoe Assistant General Manager and Chief Engineer t'
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