ML19312C437
| ML19312C437 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 05/24/1977 |
| From: | Parker W DUKE POWER CO. |
| To: | |
| References | |
| NUDOCS 7912130962 | |
| Download: ML19312C437 (2) | |
Text
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o c3 DUKE POWER COMPANY
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66-4369 Powra Brit.nswo 422 SocTa Cinencu Srazer, Cruar.orTE, N. C. 2e242 g7 WILU AM Q PAR KER, J R.
Tescame=c; Anc 704 Vice Passiormt 373-4083 Sega= Pacoweto=
May 24,1977 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.d, this report is submitted describing a condition in which a measured level of radioactivity exceeded the control level by greater than four times but less than ten times.
On April 25, 1977, analytical results of composited raw water supply grab samples collected in mid-January, February, and March,1977 vere reviewed. A summary of the pertinent results of the radioactivity concentrations in these samples is given below:
Sample Location Tritium Concentration 004.1 Seneca (Control)
(2.8 + 0.7) E-7 uCi/ml 006.1 Clemson (1.8 + 0.1) E-6 pCi/ml Tritium concentrations in downstream water samples are dependent upon the tritium concentrations of liquid effluent released from the station.
For the period January 1 through March 15, 1977 a total of 601 curies of tritium were released from the station in liquid effluents. The average release rate for the period was 8.2 Ci/ day.
Dilution and dispersion of tritium in liquid ef fluents 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 dispersion only. Conservatism was used in selecting parameters for substitution in the instantaneous release equation to determine the concentration of effluents at Clemson water,d) 9\\
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o.* O Mr. Norman C. Moseley Page 2 May 24,1977 intake. These assumptions were (1) the elevation of Lake Hartwell is 654.00 feet, (2) the flow of the Keovce River is 1100 cfs, the yearly average, and (3) an instantaneous release of 8.2 Ci of tritium is made each day several days prior to sampling. The peak concentration which would result at the 006.1 sample point is 4.0E-6 pCi/ml.
This calculated tritium concentration is about a factor of 2.3 greater than the observed value of 1.8E-6 pC1/ml. Therefore, the observed concentration is within the limits of conservative calculated values.
The Final Environmental Statement for Oconee states that "the largest estimates of dose to the 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 1.8 x 10-6 pCi/ml of tritium is 0.18 mrem / year if these tritium concentrations were maintained over the year. This estimate of Jose is less than 0.15%
of the dose from natural background and less than 0.04% of the limits of 10CFR20. Therefore, it is concluded that the observed anomalous tritium concentration does not adversely affect public health and safety.
Ve truly yours, utu U.
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William O. Parker, Jr LJB:vr e Il c..
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