ML19210A089

Nonroutine 30-Day Environ Rept 75-01:downstream River Grab Samples Showed Tritium Concentration Four Times Control Station Value.Possible Cause:Irregular Discharge Schedule W/Samples Taken Following Condensate Tank Discharge

ML19210A089
Person / Time
Site:	Three Mile Island
Issue date:	04/18/1975
From:	METROPOLITAN EDISON CO.
To:
Shared Package
ML19210A086	List: ML19210A085 ML19210A089
References
75-01, 75-1, NUDOCS 7910240810
Download: ML19210A089 (2)

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ENCLOSURE d

hetropolitan Ediso1 Company Three Mile Island Nuclear Station Unit (TMI-1)

Docket No. 50-289 Operating License No. DPR-50 Nonroutine 30-Day Environmental Report 75-01 Report of an Anomalous Meastered Level of Radioactivity Description o_f Measured Level A conthly composite of weekly grab samples of surface river water coller.ted about 1/2 mile downstream fr9m the TMI-l river discharge had a total tritium activity of 1.67 x 10- pCi/cc as reported to Met-Ed on March 21,1975. This value is greater than four times the centrol station value of 2.5 x 10- pC1/ce, which was determined by Met-Ed's consultants during the station pre-operat.d.on period.* The next river water sample analyzed from the same station location showed that the tritium level was normal.

Fossible Cause Discharges are made from the TMI-1 Liquid Waste Condensate Storage Tanks on an irregular schedule based on unit operating conditions. Weekly grab samples for the radiological environmental monitoring program are taken on a regular basis. It is believed that the grab samples which were co= posited to form this sample were taken during periods of con-densate storage tank discharge and, accordingly, during periods of higher-than-normal river water tritium level.

Analysis of Peasured Level It is believed that neither the health nor safety of the public was threatened by this occurrence represented by this sample in that:

a. The level of tritium activity was less than 1/1000th of the Maximum Permissible Concentration level given in 10 CFR 20 for members of the public.

b. The level of tritium activity at the nearest downstream source of continuous public use was a background level (1.63 x 10-7 LCi/ce).

c. No Technical Specification limits vere exceeded,

d. The event resulted from normal unit operations as described in the TdI-1 Final Safecy Analysis Report.

• In our report of December 24, 1974, a value of 5.2 x 10-7 pCi/cc was given as the control station value. This value is actually the Preliminary Re-porting Level, an internally-generated notification level at which Met-Ed performs in-house investigations regarding the measured level of radiation.

It should also be noted that using the proper value of 2.5 x 10-7 p Ci/ce, the total tritium activity of the sample described in the December 2/> letter was actually in excess of ten times the control station value.

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Corrective Actions The discharge of effluents from the Condensate Storage Tank is a normal process associated wi h unit operations and is described in the Final Safety Analysis Raport. Additional monitoring is planned so that the average activity level may be more acurately determined at the point of discharge.

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