ML19312C714
| ML19312C714 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 09/26/1977 |
| From: | Parker W DUKE POWER CO. |
| To: | |
| References | |
| NUDOCS 7912190922 | |
| Download: ML19312C714 (2) | |
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1 DUKE POWER COMPA~SY Powen Bunt. DING 422 Socin Cnuncu Srazzi CnAntorrz. N. C. 2824a N
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September 26, 1977 WCE Pats 60 tut It6ta=cNE: ANCA 704 5ttane pocovetion 373-4093 i
Mr. James P. O'Reilly, Director-U. S. Nuclear Regulatory Commission Suite 1217 230 Peachtree Street, Northwest Atlanta, Georgia 30303 RE: Oconee Nuclear Station Docket Nos. 50-269, -270, -287
Dear Mr. O'Reilly:
Iursuant to the requirements of Oconee Nuclear Station Technical Speci-f fication 6.6.2.2.d, this report is submitted describing a condition in which a measured level of radioactivity exceeded the control level by greater than 10 times.
On September 20, 1977 analytical resuits of bottom sediment samples collected in August, 1977 were reviewed.. Given below is a summary of the pertinent results of the radioactivity concentration of these samples.
Sample Location Type of Sample Radionuclide Concentrations pCi/g (dry) 000.5 One mile radius of Bottom Sediment Cs-137
< 2.0E-1 site and Lake Keowee Cs-134
< 1.9E-1 (Control) 005.2 Hwy. 27 at Bridge Bottom Sediment Cs-137 4.9E0 Cc-134 3.0E0 The expected buildup of activity in sediment downstream of the.tation effluent release point may be estimated from the shoreline deposit model (EQT A-5) on page 1.109-30 of Regulatory Guide 1.109.
The specific information required for the model is the location water-concentration of each radionuclide found in the sediment' samples and the station life to date (4 years).
Since Cs-134/137 concentrations are rarely detectable ~
at the 005.2 location, the tailrace Cs-134/137 concentrations (which are, detectable) were related to the 005.2 location by comparing dilution and dispersion of tritium between the tailrace and the 005.2 location For 7912190 % 2 g
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tritium an average dilution factor of roughly 10 has been observed between the tailrace and the 005.2 location.
This factor was applied to the average Cs-134/137 tailrace concentration from January through December, 1976 to derive the water concentrations given in the following table. This table provides a comparison of expected and actual concentrations.-
Expected Actual Radionuclide Water Concentration Sediment Concentration Sediment Concentration pCi/ml pCi/g pCi/g Cs-137 2.0E-8 1.0E1 4.9E0 Cs-134 1.0E-8 3.0E0 3.0E0 With be'. tom sediment samples, the calculated or expected concentrations of radionuclides, based on the diluted tailrace concentrations, are compara-ble to those actually determined by laboratory analyses for all radionuclides.
Therefore, the measured results of this sample are within the expected values of radionuclide concentrrations in sediment downstreets of Oconee Nuclear Station.
Very truly yours,
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i William O. Parker, Jr.'
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