ML19308A943
| ML19308A943 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 11/17/1976 |
| From: | Parker W DUKE POWER CO. |
| To: | |
| References | |
| NUDOCS 7912120717 | |
| Download: ML19308A943 (2) | |
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November 17, 1976 VtCF PatSiOCMT TELCPMONg:Asta7C4 Sf tau Pa00vC?iose 373-4093 Mr. Norman C. Moseley, Director U. S. Nuclear Regulatory Commission Suite 818 230 Peachtree Street, Northwest Atlanta, Georgia 30303 Re: Oconee Nuclear Station Docket Nos. 50-269, -270, -287
Dear Mr. Moseley:
Pursuant to the requirements of Oconee Nuclear Station Technical Specification 6.6.2.2.c & d, this report is submitted describing cor.ditions in which measured levels of radioactivity exceed the control levels by greater than four times but less than ten times.
On November 8, 1976, analytical results of composite water supply samples collected in July, August, and September, 1976 were reviewed. Given below is. a summary of the pertinent results of the radioactivity concentration of these samples:
Sample Location Type Sample Tritium Concentration 004.1 Seneca (Control)
Raw Water (2.00 1 0.70) E-07 pCi/ml 006.1 Clemson Raw Water (1.48 1 0.11) E-06 uCi/ml 012 Anderson Raw Water (8.30 1 0.90) E-07 pCi/ml 004.1 Seneca (Control)
Finished Water (2.10 1 0.70) E-07 pCi/ml 006.1 Clemson Finished Water (1.53 1 0.11) E-06 pCi/ml 012 Anderson Finished Water (9.20 1 0.90) E-07 pCi/ml Tritium concentrations in the water samples collected are dependent upon the tritium concentrations of liquid effluents released from the station. For the months of July, August, and September, 1976 a total of 459 Curies of tritium were released from the station in liquid effluents. The maximum tailrace concentration of tritium wac 3 x 10-3 uCi/ml. The average tailrace concentration of tritium was 1.79 x 10-6 pCi/ml. The station's sbjective cM i 791s no.7,7,
4-Pags 2
-Novrmbar 17, 1976 (Technical Specification 3.9) in making effluent releases is to maintain the average concentration of tritium in liquid effluents upon release from the Restricted Area to not more than 5 x 10-6 pCi/ml. Technical Specification 3.9.2 specifies that the quarterly average concentration of tritium released from the Restricted Area shall not exceed 1 x 10-5 pCi/ml. Therefore, it can be seen that the average tritium concentration for the quarter in liquid effluents is within the objective concentration and well below the specified quarterly average concentration.
Dilution and dispersion of tritium in liquid effluents between Oconee Nuclear Station and the Clemson water intake has been calculated using the equation for instantaneous release taken from the U. S. Geological Survey Paper No.
443-B, " Dispersion of Dissolved or Suspended Materials in Flowing Streams" by Robert E. Glover (1964), p.5.
This equation accounts for longitudinal dis-persion only. Conservatism was used in selecting parameters for substitution in the instantaneous release equation to determine the concentration of effluents at the Clemson water intake. These assumptions were (1) the cievarDn of Lake Hartwell is 654.00 feet and (2) the flow of the Keowee River is 1100 cfs, the yearly average.
Listed below are the resulting calculated concentra-tions of tritium at the Clemson water intake using the above method.
July 1.08 x 10-6 pCi/ml August 1.45 x 10-6 pCi/ml September 2.83, i n-6 pCi/ml Average 1.7 pCi/ml These calculated tritium concentrations are nearly the same as those observed; with water samples collected over July, August, and September, 1976 at the Clemson water intake having an average tritium concentration of about 1.79 x 10-6 pCi/ml. Therefore, the observed concentrations are within the limits of conservative calculated values.
The Final Environmental Statement for Oconee states that "the largest estimates of dose to individuals from liquid effluents are at Clemson and Pendleton where drinking water is withdrawn from the Keowee River.
The radionuclide making the most important contribution to dose at these locations is tritium (more than 50%)." The dose estimate for any individual consuming Clemson water containing 1.79 x 10-6 uCi/ml of tritium is 0.18 mrem / year if these tritium concentrations were maintained over the year. This estimate of dose is less than 0.5% of the dose from natural background and less than 0.1% of the limits of 10CFR20.
Therefore, it is concluded that the observed anamalous tritium concentrations do not adversely affect public health and safety.
Very truly yours, 2(,p-William O. Parker, Jr.
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