ML20059E031

Addendum to, Semiannual Radioactive Effluent Release Rept, Jan-June 1989

ML20059E031
Person / Time
Site:	Rancho Seco
Issue date:	06/30/1989
From:	SACRAMENTO MUNICIPAL UTILITY DISTRICT
To:
Shared Package
ML20059E008	List: ML20059E003 ML20059E009 ML20059E014 ML20059E019 ML20059E024 ML20059E028 ML20059E031 ML20059E035
References
NUDOCS 9009100008
Download: ML20059E031 (2)

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I RSNGS SEM6 ANNUAL RADIOACTNE EFFiUENT RELEASE REPORT 1

JANUARY. JUNE 1990 i

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ADDENDUM i

CORR 2CTIONS TO THE JANUARY TO JUNE 1969 SRERR I

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I mswos sEMANNUAL PEDCACTNE EFFLUENT MELEASE REPORT JANUARY JUNE 1see I

On January 3, an in-line pH sample probe located on tne B RHUT leaked following I

maintenance on that instrument. Approximately 20 gallons of the RHUT contents went to a storm drain leading directly to the plant effluent. The amount of activity released was conservatively estimated as:

H3 2.04E-05 Cl Cs 134 3.92E-10 Ci Cs 137 1.48E-09 Cl The resulting exposure to the most restrictive offsite receptor (adult whole body) was calculated to be 6.8E-07 mrom or approximately 0.000023 percent of the annual I

limit provided in Technical Specifications. The cause of the event was personnel error in replacing the retaining ring inside the probe, and programmatic action to prevent reoccurrence was not appropriate.

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RADIOACTNE EFFLUENT MONITORING INSTRUMEPGATION INOPERABLE FOR GREATER THAN 30 DAYS I

The Flow Element FE.15044 for R15044, the Gaseous Effluent Monitor for the Reactor Building Duct, was inoperable from 2/21/89 through the end of the reporting period. The I

flow element was inoperable because of continual problems with meeting the acceptance criteria of the quarterly surveillance procedure. The flow element is a thermal anemometer type and produces inconsistent results due to turbulent flow through the affluent exhaust stacks.

.I During the reporting period, there were no other effluent radiation monitors out of service for longer than 30 days. However, pursuant to Licensee Event Report 89-07, the following discussion on a related monitor problem is provided.

On April 26, while performing a monthly surveillance of the Auxiliary Building Stack (ABS) radiation monitor, an I&C technician had placed the monitor in purge mode, in the purge I

mode, service air is blown through the detector instead of the normal process flow, in an attempt to shorten the time required to perform the surveillance, the technician used an untested method to try to terminate the purge. The technician assumed that the method was successful; however, the monitor remained in the purge mode until May 18. The oversight was not discovered earlier because of the combination of very low concentrations normally observed in that vent and the unusually high background reading on the monitor due to electronic noise. No known plant evolutions performed during that I

time would have caused higher than average stack concentrations. A conservative estimate of the activity released was made based on worst case samples taken before the monitor was compromised. Those results are included in this report.

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