ML19312C147
| ML19312C147 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 07/28/1976 |
| From: | Parker W DUKE POWER CO. |
| To: | |
| References | |
| NUDOCS 7912060714 | |
| Download: ML19312C147 (2) | |
Text
'
hlY
' ' UKE POWER COSIPM 84 '/dI hp )?6 Powest Uunt.onno 422 Sourn Gnuncu StuerT. CitAug.oTTE. N. C,20a42 gg..jgf wi L LI A M O. PA R K E R. J R.
TELEP=ONC; ASC A 704
%CC PmCSietmT 37 3-4c e 3 Sec& Pacowcivos.
July 28, 1976 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 Specifi-cation 6.6.2.2.c and d, this report is submitted describing a condition in which a measured level of radioactivity exceeded the control level by greater than ten times and describing conditions in which measured levels of radioactivity exceeded the control level by greater than four times but less than ten times.
On July 23, 1976, analytical results of composite surface water samples collected in April and May, 1976 were reviewed.
Given below is a summary of the pertinent results of the radioactivity concentrations of these sa=ples:
Sample Location Type Sample Tritium Concentration 000.3 Bridge N. of Site on Surface Water (2.4 1 0.7) E-7 uCi/ml Hwy. 183 Connecting Canal (Control) 000.7 Bridge S. of Site on Surface Water (2.44 1 0.15) E-5 uCi/ml Hwy. 183 005.2 Hwy. 27 Bridge at Surface Water (9.7 1 0.9) E-7 uC1/ml Newry 013 Hartwell Reservoir, Surface Water (1.3410.10 E-6 uCL/ml 5.8 miles S. of Keowee Dam For April and May, 1976 a total of 231 curies of tritium was released from the station in liquid effluents.
The maximum tailrace concentration of tritium 19uoso 7/4 /
=
Mr. Norman C. Moseley Page 2 July 28, 1976
~
was 3 x 10 pCi/ml.
The average tailrace concentration of tritium was 9.16 x 10-7 pCi/ml.
The station's objective (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-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 for the two-month period that the average tritium concentration 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.
433-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 the Clemson water intake.
These assumptions were (1) the elevation of Lake l
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 concentrations of tritium at the Clemson water intake using the above method.
April 1.78 x 10" pCi/ml
-6 May 1.25 x 10 pCi/ml
-6 Average 1.51 x 10 Ci/ml These calculated tritium concentrations are nearly the same as those observed; with water samples collected over April and May,1976 ac the Clemson water intake having an average tritium concentration of about 9.16 x 10-7 uCi/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 containing 9.16 x 10 ge estimate for any individual consuming Clemson water 50 percent)." The do pCi/ml of tritium is 0.09 mrem / year if these tritium concentrations were maintained over the year.
This estimate of dose is less than 0.5 percent of the' dose from natural background and less than 0.1 percent of the limits of 10CFR20.
Therefore, it is concluded that the observed ano lous tritium concentrations do not adversely affect public health and safety.
V ry truly yours,
&.ua if.
)
William O. Parker, Jr.
EDB:vr
-