ML15112A859
| ML15112A859 | |
| Person / Time | |
|---|---|
| Site: | Oconee  |
| Issue date: | 03/02/1979 |
| From: | Office of Nuclear Reactor Regulation |
| To: | |
| Shared Package | |
| ML15112A858 | List: |
| References | |
| NUDOCS 7905250021 | |
| Download: ML15112A859 (5) | |
Text
WF RUNITED STATES NUCLEAR REGULATORY COMMISSION WASHINGTON, D. C. 20555 ENVIRONMENTAL IMPACT APPRAISAL BY THE OFFICE OF NUCLEAR REACTOR REGULATION SUPPORTING AMENDMENT NO. 69 TO.FACILITY OPERATING LICENSE NO, DPR-38 AMENDMENT NO. 69 TO FACILITY.OPERATING LICENSE NO, DPR-47 AMENDMENT NO, 66 TO FACILITY OPERATING LICENSE NO. DPR-55 DUKE POWER COMPANY OCONEE NUCLEAR STATION, UNITS NOS. 1, 2 AND 3 DOCKETS NOS. 50-269, 50-270 AND 50-287 Introduction By letter dated December 2, 1977, as supplemented September 11, 1978, Duke Power Company (the licensee) requested changes to their Environ mental Technical Specifications (ETS) for Oconee Nuclear Station.
We have discussed these proposals with the licensee and are deferring action on their request to delete limiting conditions for operation from the ETS, to which the licensee has agreed.
This amendment deletes the specifications for the General Aquatic Surveillance Program and special studies.
Water temperature, chemistry, and fisheries studies were begun on Lake Keowee prior to 1971, when Lake Keowee reached full-pond elevation. Phytoplankton, zooplankton, and benthos studies were begun around mid-1.973.
The purpose of these studies is to detect and quantify the effects of the operation of Oconee Nuclear Station (ONS) on the aquatic environ ment and to verify the findings of the Final Environmental Statement (FES).
Appraisal Dissolved Oxygen:
The FES stated that reduction of oxygen concentration in the surface waters near the plant discharge could occur during periods when the plant was drawing oxygen deficient water from the hypolimnion and discharging it to the surface. The lowest value observed during the 790525002-(
e 9
-2 1974 through 1976 period was 3.4 mg/liter. The FES indicated that the dissolved oxygen concentration could fall below 1.0 mg/liter in the discharge area. The study indicated that oxygen concen trations were considerably higher than those estimated in the FES.
Thermal:
Appendix III-1 of the FES predicted the thermal plume for various season and lake conditions. The study resulted in general con firmation of the thermal plume as well as other thermal predictions of the FES. The thermal study resulted in the following conclusions:
a) a distinct thermal "plume" from the Station discharge was evident from September through March of each year, resulting in localized vertical thermal gradients or stratification; b) a thermal plume was not apparent from April through August of each year; c) maximum summer temperatures in the lake's surface waters were only slightly different from preoperational values; d) winter minimum temperatures, except in the immediate vicinity of the ONS discharge, were mainly a function of meteorological con ditions each year; there was no significant "carryover" in the lake's heat content from one year to the next; e) ONS's use of bottom waters resulted in a less distinct summer thermocline in the lake, and complete destratification of the top 20 or 25 m of the water column earlier (mid-September) than observed in preoperational years; and f) maximum temperatures of the deep (20 to 30 m) waters of the lake in September of 1975 and 1976 were about ten degrees Celsius (18 deg. F) warmer than in the preoperational period.
Aquatic Chemistry:
The FES stated that the plant would discharge small quantities of chemicals into Hartwell Reservoir and that these discharges were not expected to have discernible effects in the reservoir. The results of the monitoring program generally confirm this prediction.
The results of the monitoring program can be summarized as follows:
-3 a) Lake Keowee has low dissolved and suspended solids and nutrient concentrations, low hardness, and is mildly acidic; b) the mineral composition of the lake during the ONS operational period was very similar to-that of the Keowee River prior to its impoundment; c) based on the nitrogen/phosphorus ratios observed, phosphorus appeared to be the limiting nutrient for primary production in Lake Keowee; total phosphorus, ammonia and nitrate-nitrite concentrations have steadily decreased since the reservoir was impounded, probably due to natural "aging;" and d) seasonal fluctuations in the concentrations of ammonia, nitrate nitrite, manganese and iron, among others, were Tess pronounced during the ONS operational period than they were previously, attributed to the induced mixing and resultant higher dissolved oxygen content of the lake caused by ONS's use of bottom waters.
Fisheries Studies:
The FES predicted that some fishes would be impinged on the intake screens, and that shad could possibly die in large numbers during the winter months. The FES also discussed in detail the potential thermal effects on fishes due to the heated discharge.
The studies indicate that the overall effect of the Station on the fish populations was small and they generally confirm the findings of the FES. No gas bubble disease was observed in any of the fish sampled in the program. Very little impingement and entrainment was observed. Fishes tended to reproduce in the shallower areas of the lake and not in the long, deep intake canal; therefore, entrain ment of young fish forms into the plant was small.
The studies of species composition.and general distribution of fish in the lake indicate no adverse effects resulting from the operation of the Station. While abundance of many species has changed during the study period, these changes could not be distinguished from those predicted to occur naturally.
Phytoplankton and Zooplankton:
The FES stated that the plant may cause shifts in the dominance of green algae to the undesirable blue-green types in small areas of the lake. The FES also suggested that some suppression of photo synthesis could occur for organisms passing through the condensers.
The study showed that there was neither a shift to obnoxious blue green algae types, nor was there any appreciable decrease in photo-.
synthesis rates as a result of entrainment.
S
-4 The FES stated that during the months of August and September, the lengthy exposure to temperatures approaching or exceeding the thermal tolerance limits could cause a reduction in zoo plankton organisms in the thermal plume. The zooplankton abundance in the surface water near the Station discharge was similar to the abundance in the intake cove, but substantially lower than in most other areas of the lake. This is because the skimmer wall allows only deep water, which has lower concen trations of organisms, into the intake canal. The design minimizes the impact on these organisms. The actual entrainment had little effect on the viability of these organisms. Overall, the effect of the plant on these populations was less than that predicted in the FES.
Benthos and Periphyton:
The FES stated that the discharge flow could cause some scouring and would probably-eliminate all benthic organisms in the immediate discharge area. The study showed that there was little, if any, effect on the benthic population. Bottom type and depth appeared to be the important factors determining the type-of benthos population. Further, no substantial changes in taxonomic composition of benthos were observed over the operational period.
Periphyton was studied because of its value as an indicator of major spatial or temporal changes in water quality. The results of the program indicate that, although year-to-year and spatial differences were observed, the operation at the Station did not significantly change the trophic status or water quality of Lake Keowee with respect to the periphyton community.
Conclusion and Basis for Negative Declaration We conclude that the impact of the Oconee Nuclear Station on the aquatic environment is within the bounds of the FES, as indicated above, and that the environmental impact of the Station has stabilized' As a consequence, the General Aquatic Surveillance Program and Special Study Programs of the ETS are no longer needed and may be terminated immediately.
On the-basis of the foregoing analysis, we conclude that there will be no environmental impact attributable to the proposed action.
The changes assessed herein are to the environmental monitoring programs and do not involve any change in plant design or operation or involve an increase in effluent types or quantities. The impact of the overall plant has already been predicted and described in the Commission's FES for ONS.
On this basis and in accordance with 10 CFR §51.5, the Commission concludes that no environmental impact statement for the proposed action need be prepared and a negative declaration to this effect is appropriate.
Dated:
March 2, 1979
Dke Power Company cc w/enclosure(s):
Mr. William L. Porter Mr. Robert B. Borsum Duke Power Company Babcock & Wilcox Post Office Box 2178 Nuclear Power Generation Division 422 South Church Street Suite 420, 7735 Old Georgetown Road Charlotte, North Carolina 28242 Bethesda, Maryland 20014 J. Michael McGarry, III, Esquire rc w/enclosure(s) and incoming DeBevoise & Liberman dtd.: 6/9/78 700 Shoreham Building 806 15th Street, N.W.
Office of Intergovernmental Relations Washington, D. C. 20005 116 West Jones Street Raleigh, North Carolina 27603 Oconee Public Library 201 South Spring Street Walhalla, South Carolina 29691 Honorable James M. Phinney County Supervisor of Oconee County Walhalla, South Carolina 29621 Chief, Energy Systems Analyses Branch (AW-459)
Office of Radiation Programs U.S. Environmental Protection Agency Room 645, East Tower 401 M Street, S.W.
Washington, D.C.
20460 U. S. Environmental Protection Agency Region IV Office ATTN:
EIS COORDINATOR 345 Courtland Street, N.E.
Atlanta, Georgia 30308 U. S. Nuclear Regulatory Commission Region II Office of Inspection and Enforcement ATTN:
Mr. Francis Jape P. 0. Box 85 Seneca, South Carolina 29678 re wenclsur~s) nd icomN