ML19329B035

RO 78-072-04-T-0:on 780710,station Effluent Chlorine Concentration Exceeded Tech Spec Limits.Caused by Personnel Mistakenly Returning Intake Chlorinator to Automatic Return to Svc to Be Expedited

ML19329B035
Person / Time
Site:	Davis Besse
Issue date:	07/18/1978
From:	TOLEDO EDISON CO.
To:
Shared Package
ML19329B033	List: ML19329B032 ML19329B035
References
NUDOCS 8001290747
Download: ML19329B035 (1)

Text

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_UBJECT: Limiting Condition Report Level Exceeded, NP10-78-01 .

DATE_OF EVENT: July 10, 1978 FACILITY _: Davis-Besse Unit 1 IDENTIFICATION OF OCCURRENCE:

Station affluent chlorine concentration > 0.5 ppm.

CONDITIONS PRTOR _TO OCCURRENCE The unit was in Mode 5 with Power (MWT) = 0 and Load (MVE) = 0.

DESCRIPTTON OF OCCURRENCE:

On July 10,1978, at 1400 hours0.0162 days <br />0.389 hours <br />0.00231 weeks <br />5.327e-4 months <br /> Chemistry and Health Physics personnel detected during a routine daily samplin5 a free available chlorine concentration of 1.4 ppm in the collection box cffluent from the circulating water blowdown. This cot'-

centration exceeds the Ifmit of Enviror.tnenral Technical Specification Section 2.3.1 and the National Pollutant Discharge E11rnination System Permit of 0.5 ppm maximum.

All chlorinating of both intake and circulating water was suspended by 1500 hours0.0174 days <br />0.417 hours <br />0.00248 weeks <br />5.7075e-4 months <br />.

10, 1978, at p)

( Tom Tamo41ag, NRC Region III, was notified by telephone on July 1700 hours0.0197 days <br />0.472 hours <br />0.00281 weeks <br />6.4685e-4 months <br /> and by a telecopy sent on July 11, 1978, at 0955 hours0.0111 days <br />0.265 hours <br />0.00158 weeks <br />3.633775e-4 months <br />.

s" lt appears from the turn of events that this condition was present since Friday

[V T

afternoon, July 7, 1978. ,

DESIGUA-~~.N OF A_PPARENT CAUSE OF CCCURRENCE:

The cause of this occurrence is personnel error. The Instrument and Control mechanic responsible for returning the Circulating Watar Chlorinator to AUTO fren MANUAL (continuously chlorinating) on Friday af ternoon, July 7,1978, mis-takenly returned the Intaka Chlorinator to AUTO instend. The Circulating Water Blowdown in directed through the collection box where the sample was taken. l ANALYSIS 0F OCCURRENCE:

1 The level of chlorine which existed was not harmful; there was no evidence of I l

any fish being killed .ts a result of the incre.ased chlorine concentration.

CORRECT 1yE ACTION:

The racerder and computer alarm point ancociated with the autcmatic chlorine analyzer at the beach sample station were out of service awaiting replacenent pet ts.

The return of those to service vill be arpedited. Had the alarm been received, the time that we exceeded the limit would have been reduced.

FAILURE DATA:

b g(J There hav. h..n no previous sim11ar occurrences. .

Reportable Occurrence No. 78-072-04-T-0 80012$0 M7

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