ML20236J075

Investigation of Impact of Sequoyah Nuclear Plant on Dissolved Oxygen Levels in Chickamauga Reservoir, Status Rept for Apr-Sept 1987

ML20236J075
Person / Time
Site:	Sequoyah
Issue date:	09/30/1987
From:	Brooks R TENNESSEE VALLEY AUTHORITY
To:	Stewart P TENNESSEE, STATE OF
References
NUDOCS 8711050125
Download: ML20236J075 (7)

Text

9

.o - .

- Investigation of the Impact of Sequoyah Nuclear Plant on Dissolved Oxygen Levels in Chickamauga Reservoir Status Report: April - September 1987 The final' plan for the Chickamauga Dissolved Oxygen (DO) Study called for four. basic areas of work: water quality modeling, field . studies to calibrate the model, Lfield investigations of mixing zone dynamics in the-I vicinity of ~ the diffuser discharge, and in-plant monitoring to determine effect of the plant on D0 levels in the diffuser discharge. The status l

of each of these areas of investigation is presented below.

-I. water Quality Modeling A generalized two-dimensional model of the reservoir has been developed and is being used' for water. quality simulation.

Preliminary calibration of the model- for temperature has been performed using 1986 field data, with special attention being given l- to the flow field at the underwater dam and to temperature patterns near the plant. Calibration of DO and other water quality parameters will be performed as soon as the 1987 field data and the sediment oxygen demand (SOD) measurements become available. No major problems have been encountered with this portion of the study.

It II. Field Studies for Model Calibration A. Regular Monitoring The regular monitoring portion of the study consisted of 33 sampling stations at 19 locations (17 on the Tennessee River and 2 on the Hiwassee River). Biweekly monitoring began on April 1.

Hydrolab profiles (DO, conductivity, temperature, and pH) were 8711050125 B70930 PDR ADOCK 05000327 /

R PDR 41 h

, i

1. ' performed at all locations, fluorometry sampling was conducted at 15: locations, and ' nutrient sampling was performed at 13. river mile locations. No major problems have been encountered with this portion of the study. The regular monitoring is continuing through fiscal year 1988. I B. ~ SOD Studies i

' The SOD studies were originally scheduled to be conducted during

the summer of 1987. However, due to laboratory equipment and 1 sampling problems, these studies were not. . done . These studies are currently planned to be conducted - from late April to - June 1988. This should not delay calibration of the model 'to the point that the overall project schedule is delayed, i

III. Mixing Zone' Studies ;j A .' DO Profile Surveys  !

These surveys began on July 1 (the DO in releases from Watts Bar Dam did not drop below 4.0 mg/L until June 30) and were conducted biweekly on the weeks when the regular monitoring was not scheduled. No maj or problems were encountered during this portion of the study. The D0 profile surveys were completed on September 23. 'In combination with the regular monitoring program, weekly monitoring of DO conditions in Chickamauga was conducted from the week of June 22 through the week of September 28 (15 weeks). .

1 l

1 1

i

, o B. Dye Tracer St g The dye tracer study was performed on June 15-16 to explore the effect of the SQN underwater dam on vertical mixing as flow moves past the dam, Results indicate that the underwater dam induced some vertical mixing downstream of the dam. However, this vertical mixing was not sufficient to eliminate the relatively weak thermal stratification of 1*C that existed in the upper six meters. Natural channel mixing (induced by the river bend) and lateral spreading of the dye ribbon made it impossible to quantify the individual mixing processes. The study revealed that the mixing induced by the underwater dam does affect the D0 distribution downstream from the dam.

IV. In-Plant Monitorinr, Study The in-plant monitoring study was conducted from May 1 through October 19. Monitoring will resume on May 1, 1988, if SQN is operational. The study was initially plagued by equipment breakdowns. However, new Hydrolab Surveyor II monitors were installed at the intake skimmer wall and at the discharge from the diffuser pond in July 1987; these new monitors have been performing reliably for the past three months. The monitor at the middle station (the inlet to the diffuser pond) has not been very reliable, however, and has experienced a high degree of lost record (61 percent). New equipment has been ordered for FY 88 and should correct this situation.

l I

_ _ _ _ _ _ _ _ _ _ _ _ _ . - _ . - )

j  ; .

V. Summ.ary l The overa11 ' s tudy is generally going well and the problems which have been encountered are being, solved with no projected impact on 1

the overall project schedule.

l l

l I

1

)

I l

J

^

TENNESSEE VALLEY AUTHORITY KNOXVILLE. TENNESSEr 37902 o .

(

• OCT 301987 Mr. Philip L. Stewart, Manager Chattanooga Field Office Division of Water Pollution Control 2501 Milne Street Chattanooga., Tennessee 37406-3399

Dear Mr. Stewart:

- NPDES PERMIT NO, TN0026450 - INVESTIGATION SEQUOYAH NUCLEAR PLANT (SQN)

OF PLANT IMPACT ON DISSOLVED OXYGEN (DO) LEVELS IN CHICKAMAUGA RESERVOIR - STATUS REPORT In accordance with our April 30 study plan for this project, enclosed 10 a status report for the period of April 1 to September 30, 1987. If you

have any comments concerning this report, please call Madonna Martin of f my staff at f.615} 632-6695.

Sincerely, b- '

Ralph H. Broo ts, Director Environmental Quality Enclosure cc (Enclosure):

Mr. Billy H. Adams, Chief

' Ecological Support Eranch U.S. Environnantal Protection Agency College Station Road Athens, Georgia 30601 Mr. Bruce R. Barrett, Director l Water Management Divisicn i U.S. Environmental Protection Agency Region IV 345 Courtland Street, NE I Atlanta, Georgia 30365 l Mr. Paul E. Davis, Deputy Director Division of Water Pollution Control Tennessee Department of Health '

and Environment  !

TERRA Building 150 Ninth Avenue, North Nashville, Tennessee 37219-5404 l l

Continued on page 2  !

'} is )

i An Equel Opportunity Employer {

J

_ : .7r n.; -

. '+ }

L

. , Mr. Philip L. Stewart DCT 301987 cc (Enclosure):

Mr. Charles H. Kaplan, P.E.

Coordinator, Thermal Analysis Permits Section Water Management Division U.S. Environmental Protection Agency, Region IV 345 Courtland Street, NE.

Atlanta, Georgia 30365 Mr. Douglas K. Lankford, Chief South Carolina / Tennessee Unit Facilities Performance Branch Water Management Division U.S. Environmental Protection Agency, Region IV 345 Courtland Street, NE.

Atlanta, Georgia 30365 Mr. C. Wayne Pollock, Chief Fisheries Management Ellington Agricultural Center Post Office Box 40747 Room 153 j Nashville Tennessee 37204 1 Mr. Walter D. Stieglitz Acting Regional Director Department of Interior U.S. Fish and Wildlife Service Richard B. Russell Federal Duilding i 75 Spring Street, SW. l Atlanta, Georgia 30303 Mr. W. Reid Tatum, Regional Manage Tennessee Wildlife Resources Agency 216 East Penfield Street .

Crossville, Tennessee 38555 U.S. Nuclear Regulatory _ Commission 1 Attention: Document Control Desk Washington, D.C. 20555 1

Continued on page 3 1

l l

l i

I

__ _____ a

> - Mr. Philip L. Stewart OCT 301987 ,

cc (Enclosure):

Mr. G. G. Zech, Assistant Director Re&ional Inspections Division of TVA Projects Off4ce of Special Projects U.S. Nuclear Regulatory Commission j Region II 101 Marietta Street, NW., Suite 2900 Atlanta, Georgia 30323 Mr. J. A. Zwolinski, Assistant Director for Projects Division of TVA Projects '

Office of Special Projects U.S. Nuclear Regulatory Commission 4350 East West flighway EWW 322 __

Bethesda, Maryland 20814 e o

_ _ _ _ _ _ _ _ _ _ _ . - - _ _ _ - - . - _ _ _ _ _ _ . -