ML19317D495
| ML19317D495 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/19/1976 |
| From: | Parker W DUKE POWER CO. |
| To: | |
| References | |
| NUDOCS 7912060755 | |
| Download: ML19317D495 (3) | |
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May 19, 1976 Mr. Norman C. Moseley, Director U. S. Nuclear Regulatory Commission Suite 818 230 Peachtree Street, Northwest Atlanta, Georgia 30303 Re: Oconce Nuclear Station Docket Nos. 50-269, -270, -287 Pursuant to the requirements of Oconee Nuclear Station Technical Specification 6.6.2.2.C & D, this report is submitted describing conditions in which measured 1sysis of radioactivity exceeded the control levels by greater than ten times and describing conditions in which measured levels of radioactivity exceeded ths control levels by greater than four times but less than ten times.
On May 14, 1976, analytical results of surface water saaples collected on a monthly frequency for January 1976 and composite water supply samples collected in January and February 1976 were reviewed.
Given below is a summary of the partinent results of the radioactivity concentration of these samples:
Sample Location Type Sample Tritium Concentration (uC1/ml) 000.3 Bridge N. of Site on Surface Water (2.90 1 0.70) E-7 Ilwy. 183 Connecting Canal (Control) 000.7 Bridge S. of Site on Surface Water (1.52 1 0.09) E-5 Hej. 183 005.2 Hwy. 27 Bridge at Surface Water (5.07 1 0.30) E-6 Newry 013 Hartwell Reservoir, Surface Water (3.22 1 0.20) E-6 5.8 miles S. of Keowee Dam 004.1 Seneca (Control)
Raw Water (2.00 1 0.70) E-7 006.1 Clemson Raw Water (4.4610.26) E,-6 '
6 012 Anderson Raw Water (1.43 1 0.10) E-6
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May 19, 1976 Page 2 004.1 Seneca (Control)
Finished Water (2.00 1 0.60) E-7 006.1 Clemson Finished Water (4.25 1 0.26) E-6 012 Anderson Finished Water (1.34 1 0.10) E-6 For the months of January and February 1976, a total of 620 Curies of tritium werereleasedfromthestationinlguideffluents. The maximum tailrace concentration of tritium was 3 x 10 pC1/ml, and the average tailrace tritium 6
concentration was 2.84 x 10 uCi/ml. As stated in Technical Specification
), the station's objective in making effluent releases is to maintain the w.arageconcentrationoftritiuminliggdeffluentsuponreleasefromthe Restricted Area to not more than 5 x 10 uCi/ml.
Technical Specification 3.9.2specifiesthatthequarterlyaverageconcegrationoftritiumreleased from the Restricted Area shall not exceed 1 x 10 pCi/ml. Therefore, it can be seen that for the quarter the averace tritium concentration in liquid effluents is within the objective concentration and all 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.
433-B, " Dispersion of Dissolved or Suspended Materials in Flowing Streams" by Robert E. Glover (1964), p. 5.
This equation accounts for longitudinal Conservatism was used in selecting parameters for substitution dispersion only.
in the instantaneous release equation to determine the concentration of effluents at the Clemson water intake. These assumptions were (1) the elevation of Lake llartwell is 654.00 feet and (2) the ilow of the Keowee River is 1100 cfs, the Listed below are the resulting calculated concentrations of yactly average.
tritium at the Clemson water intake using the above method:
-6 January 5.58 x 10 Ci/ml l
-6 February 6.94 x 10 pCi/ml
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Average 6.26 x 10 uCi/ml Thu e calculated tritium concentrations are nearly the same as those observed; with water samples collected over January and February 1976 at the Clemsgn water intake having an average tritium concentration of about 4.36 x 10_ pCi/ml.
l Therefore, the observed concentrations are within the limits of conservative l
calculated values.
l The Final Environmental Statement for Oconee states that "the largest estimates of dose to individual.; from liquid effluents are at Clemson and The Pendleton where drinking water is withdrawn from the Keowee River.
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May 19, 1976 Page 3 radionuclide making the most important contribution to. dose at these locations is tritium (more than 50%)." The dgse estimate for any individual consuming Clemson water containing 4.36 x 10 uCi/ml of tritium is 0.44 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 10 CFR 20.
Therefore, it is concluded that the observed anomalous tritium concentrations do not adversely affect public health and safety.
Very truly yours, b(. 0 JZ William O. Parker, Jr.
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