RBG-25309, Requests Mod of Water Discharge Permit WP0409,changing Discharge Limitations for Parameter of Temp for Outfall 001. Higher Temp Limits Will Not Significantly Impact Receiving Water

Requests Mod of Water Discharge Permit WP0409,changing Discharge Limitations for Parameter of Temp for Outfall 001. Higher Temp Limits Will Not Significantly Impact Receiving Water

ML20210S662
Person / Time
Site:	River Bend
Issue date:	02/06/1987
From:	Deddens J GULF STATES UTILITIES CO.
To:	Givens J LOUISIANA, STATE OF
References
RBG-25309, NUDOCS 8702170672
Download: ML20210S662 (5)

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GULF STATES UTILITIES COMPANY AlvtR GEND Station POST OFFICE 80x 220 St. FRANCISvlLLE. LOUIslANA 70776 AAtA CODE 604 636 6094 346 0661 February 6, 1987 RBG- 25309 File No. G1.ll.2 Mr. J. Dale Givens, Assistant Secretary Office of Water Resources Department of Environmental Quality P.O. Box 44091, Capitol Station Baton Rouge, LA 70804

Dear Mr. Givens:

Water Discharge Permit No. WPO409 Gulf Staten Utilities Company (GSU) hereby requests modification of the discharge limitations for the parameter of temperature for River Bend Station's Outfall 001.

When GSU applied on September 5, 1974 for an NPDES permit for its planned River Bend Station, the projected wet bulb temperatures were lower than those subsequently experienced at the site.

Discharge temperature projections were based on conceptual cooling tower design performance and without the benefit of final design heat loads and operating experience.

Experience with the as-built design during the first summer and fall (1986) of operation showed that present permit limits could not be met under normal operating procedures at maximum generating capacity.

Cooling tower acceptance tests were performed in early October by Environmental Systems Corporation, in accordance with ASME's Power Test Code 23. As part of the testing, flows were verified for both three and four circulating water pump configurations.

Operating with four pumps results in 115% of design flow.

Additional data indicated a loss of 5.5 to 6.0 megawatts in not load when only three pumps were operated. Even though four pump operation is required for plant efficiency, it was necessary to ,

conduct acceptance tests with three pumps (94% of design) to meet '

the test code requirement of 90% to 110% of design flow, Under calm wind conditions the towers performed at or near design (Attachment I). Results indicated an inverse relationship between wind velocity and tower officiency (Attachment II) due to the re* circulation of moisture-laden exhaust within and between towers. j D

8702170672 070206 (C PDR ADOCK 05000458 g p PDR

d A performance curve was constructed (Attachment II) for four pump 6 full power operation6 Using an average wet bulb of 81.1Fangamaximumof84F, the expected blowdown temperatures are 94.5 F and 96.3 F, g respectively. Adding the calculated approach deficiency of 2.0 F, attributable to a daily average wind spged of 6.5 mph, the predicted blowdown average temperatgre is 96.5 F. Adding the calculated approach deficiency of 2.6 F, based on the maximum daily average wind spged of 8.2 mph, the resultant maximum blowdown temperature is 98.9 F.

The acceptance tests indicated no way to substantially improve tower performance without expensive major modifications. No other economically feasible rothods were.found to significantly reduce blowdown temperature under sustained base load operation.

Based on the foregoing Gulf States Utilities Company requests the following modifications of the temperature limitations for Outfall 001 of Permit No. WP0409:

Ingrease Daily Average Temperature limitation from 91 F to 97 F.

U Ingrease Daily Maximum Temperature limitation from 96 F to 99 F.

GSU also requests that the method of calculation be changed so that daily average temperature becomes the average of all temperatures during the monthly reporting period and the daily maximum temperature becomes the highest twenty-four hour average for the reporting period. This change is requested to provide a consistent method of calculation for all permit parameters and to account for short term variations in wind speed.

River Bend Station is located on the lower Mississippi River and the increased temperature limits are requested for a relatively small permitted average discharge of 8.1 MGD (5,625 gpm). The requested limits are consistent with those of other permits in the same river segment.

Considering the flow rates of the discharge and the receiving j

! water, we believe that these higher temperature limits will not significantly impact the 2eceiving water. j Should you require further information please contact Mr. James  !

Cook at (504) 635-6995.

I certify under penalty of law that this document and all attachments were prepared under the direction or supervision in accordance with a system designed to assure that qualified personnel properly gather and evaluate the information submitted.

Based on my inquiry of the person or persons who manage the system, or those persons directly responsible for gathering the 1

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information, the information submitted is, to the best of my knowledge and belief, true, accurate, and complete. I am aware that there are significant penalties for submitting false information, including the possibility of fine and imprisenment for knowing violations.

Sincere ,

J. C. Deddens Senior Vice President i River Bend Nuclear Group JCD/JEB/E / O/je Attachments cca Mr. Myron O. Knudson, P.E.

Director, Water Management Division (6W)

United States Environmental Protection Agency Region VI InterFirst Two Building, 1201 Elm Street Dallas, TX 75270 U.S. Nuclear Regulatory Commission Document Control Desk Washington, D.C. 20555 U.S. Nuclear Regulatory Commission Region IV 611 Ryan Plaza Drive, Suite 1000 Arlington, TX 76011 U.S. Nuclear Regulatory Commission Senior Resident Inspector P.O. Box 1051 St. Francisville, LA 70775 I

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ATTAC HMENT I 1  ?

GULF STATES UTILITIES COMPANY RIVER BEND STATION - UNIT l' 1 ,

SUMMARY

OF COOLING TOWER ACCEPTANCE TEST DATA.

I On October 2 and 3, 1986, formal acceptance tests of the River Bend.

Station cooling towers were performed. These tests were conducted in 4 general accordance with ASME's Power Test Code 23 and applicable industry standards. Verification of. flow rates was also accomplished as part of the testing. -The objective of the tests was to determine the i thermal efficiency of the four (4) Marley Cooling Tower, Model 4AT 76507-23.5-8, circular crossuflow, mechanical draft' cooling towers installed at River Ihnd Station. The data summarized below is for those test periods when all test equipment and meteorological conditions were within test code limits. The tests were conducted by:

l i Environmental Systems Corporation

! 200 Tech Center Drive Knoxville, Tennessee 37912 ,

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SUMMARY

OF TEST RESULTS I Date 10/2/86 10/2/86 i

l Time Frame 14:00-15:50 17:30-19:20 1

j Water Flow Rate (gpm) 532,350 532,350 l

Hot Water Temperature (*F) 119.5 120.1 l

Cold Water Temperature (*F) i (Measured) 92.4 92.1 I

(Corrected *) 92.5 92.2 Ambient Dry Bulb Temperature (*F) 87.5 80.9

! Ambient Wet Bulb Temperature (*F) 77.2 78.7 i Wind Speed ** (mph)

(Average - 14

00-15:45 & 18:00-19:15) 3.9 2.2 (Maximum 15 Minute Period) 5.1 2.8 Make Up Water. Temperature ('F) 81.2 81.2 Make Up Water Flow Rate (gpm) 13,000 13,000  ;

i Fan Shaft Brake Horsepower 185.5 185.5 Capability (%) 91 97 4

• Corrected for pump power input / throttling and make up temperature.

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• • From RBS Met Tower 15 minute averages of 30 ft. wind speed.

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ATTACliMENT II GULF STATES UTILITIES COMPANY .

t RIVER BEND STATION COOLING TOWER PERFORMANCE CURVE PERFORMANCE CCRVE 100 I The perforsance curve is constructed from information supplied by the Marley Cooling Tower Company for the l

four Model 4 AT 76507-23.5-8 towers installed at River Band Station.

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• - e The curve is based on actual four e' pump operation (115% of design flow)

N and 100% thermal load, g ----- - _ _ - - - ---

--T e' s Maximum and average wet bulb temper-h e' atures are based on Ryan Airport g 93 '

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--- Baton Rouge, NOAA) meteorological e _ _

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n VET BUL8 C e' TEMPERATURE -

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3 ,' , ,

(84'F) -

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- AVERACE WET BCta ' '

TEMPERATtM 1 m (81.1*F) , ,

90 75 80 8$

WET ICL8 TCtPERATURE (*F)

WIND INDUCED APPROACH DEF?CIENCY APPROACH DEFICIENCY 4.0 Approach deficiency is based '

on field measurments taken during acceptance tests by Environmental Systems Corp.  ; 8.2 MPH Wind Speed Applied to Maximum l Wind speed data ir feca two w 3.0 6.5 MPH Wind Speed App 1ted to Average years of River Bend Station , , ,

':"'"""'i':"'5%

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'---------A' Rouge. NOAA) data. {w -

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$1TE MIT TokT.R VIND $ PEED (MPH 0 30 FT.)

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