ML20079M945
| ML20079M945 | |
| Person / Time | |
|---|---|
| Site: | Cook  |
| Issue date: | 03/31/1980 |
| From: | ETA ENGINEERING, INC. |
| To: | |
| References | |
| RTR-NUREG-1437 AR, NUDOCS 9111110011 | |
| Download: ML20079M945 (53) | |
Text
. _ _ _ _ _ - _, _ _ _ - - - -
o f
IllDI ANA & MICh1 gat 1 ELECTRIC COMPAfiY 00NALD C. COOK NUCLEAR PLANT, UNITS 1 AND 2
SUMMARY
REPORT COMPARING THE D. C. COOK THERMAL PLUME MEASUREMENTS WITH MODEllflG PREDICTIONS Prepared by:
ETA Engineering. Inc.
415 East Plaza Drive
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Westmont, Illinois 60559 l.
i March, 1980 l
9111110011 000331 PDR NUREG 1437 C PDR
I TABLE Of CONTENiS E399
- 1. 0 INTRODUCTION,..
I 1.1 Technical Specification Requirements 1
- 1. 2 Objectives of This Report.
1
- 2. 0
SUMMARY
OF THE MONITORING EFFORT.
3 2.1 Monitoring Periods 3
2.2 Summary of Monitoring Results.....
4 2.2.1 Plume Areas, Widths, and Volurnes..........
5 2.2.2 Plume Thickness 7
2,2.3 Centerline remperature Decay........
7 2.2.4 Seasonal Variations 12 2.2.5 Areas of Influence.
'3 J
- 2. 3 Ambient Conditions 13 2.3.1 Ambient Lake Temperature..............
13 2.3.2 Ambient Le.ke Currents 18 2.3.3 Stratification...................
24
-3.0
SUMMARY
OF MODELING [FFORT..............
25 3.1 Hydraulic Model..........,
25 3.2 Mathematical Models..........,..........
26
- 3. 3 Modeling Results 28 4.0 ' COMPARISON OF FIELD DATA WITH PREDICTIONS 31 4.1 Plume Areas.
31 4.2 Centerline Temperature Decay Rate.........
32
- 4. 3 Plume Depths 4.4 Plume Volume.......,,...........,..
40 40 4.5 Region of Influence.
41 5.0
SUMMARY
43 REFERENCES 45 APPENDIX 46 i
l ii i
1 i
O LIST OF FIGURES No.
.Page 1
Excess Temperature vs. Distance (August-September, 1978).
8 2
Excess Temperature vs. Distance (November, 1978) 9 3
Excess Temperature vs. Distance (July, 1979) 10 1
4 Region of take Influence by D. C. Cock Units 1 & 2 Discharge.......
14 5
Lake Ten.perature Data (6/22/78-8/20/78).
15 6
Lake Temperature Data (6/22/78-8/20/78).
16 7
Lake Current Data Plots.
20 8
Lake Current Data Plots.
21 9
Current Directional Persistence (1979) 23 10 Hydraulic Test Data (9/2/72, 9/22/72, 10/2/72, 10/11/72).....,
33 11 Hydraulic Tei.t Data (11/16/72, 11/20/72) 34 12 Hydraulic Test Data (11/17/72, 11/21/72) 35 13 Hydraulic Test Data (9/8/72, 9/15/72, 11/15/72, 11/22/72)....
36 14 Excess Temperature vs. Distance (July, 1979) 37 15 Excess Temperature vs. Distance (August-September, 1978)........
38 16 Excess Temperature vs. Distance (November, 1978) 39 Re0 on of Lake Influence by D. C. Cook Units 1 & 2 i
17 42 Discharge.
iii i
e LIST OF TABLES No.
,Pj{tge 1
Summary of Plume Areas, Width, and Volumes.......
6 2
Predicted Plume Areas vs. Lake Current Speeds 29
-3 Predicted Plume Temperature and Velocity vs. Distance 29 4
Predicted Plume Areas, Depths, and Volumes....
30 5
Predicted Maximum Extent of Plume (derived from a
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variety of current conditions),,,..........
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1.0 INTRODUC110N t
_ 1.1 Technical Specification Requirenents
_,l' The Environmerital Technical Specificationst for the Donald C.
Cook Nuclear l'
Plant Units _1 and 2 = state the following objectives for monitoring the lake
-t water temperature in the _ region of the plant: (1) determine the thermal f
characteristics of the lake within the defined study area, (2) determine the size, shape, and location of the thermal plume under different wind and lake j-current conditions,. and (3) determine if the thermal discharge is in com-
- pliance with -the thermal criteria of the Michigan Water Resources Commission.
These Technical Specifications called for monitoring the thermal plume while the two units are operating at, at least, 75% of rated power during four_ study
-periods scheduled'as -follows:
15 February - 15 March 15 April - 15 May f
-15 June - 15 September l
1 November - 1 December i
Each study period wa: to consist of a minimum of five sampling days with two
. lume resolutions -made_ during each day, dependent upon seasonal weather condi-l p
tions.
The _ monitoring 'ef fort was to determine (1) the area within the A3 F isotherm,-(2)1 location-of the plume centerline, (3) rate of excess temperature decrease, (4) plume width, (5) thickness of the plume, and (6) depth of the winter sinking plume.
The Technical Specifications required the data to be displayed as isotherm
" diagrams showing the area enclosed by the A3"F isotherm.
The data from these
-studies were tol be used to verify the analytic and/or hydraulic models used to predict the-size and' location of the thermal plumes.
The lake current data, as measured by drogues and in situ current meters, were to be correlated with the meteorological data.
L2-Objectives of This Report I
-The primary objective of this report is to provide a comparison of the field data with the analytical and hydraulic models used to predict the thermal
s.
plume characteristics.
A second objective is to summarize the rnonitoring effort and to demonstrate why, even thou0h the winter ruonitoring period was 3
1 I
missed and the spring monitoring ef fort was delayed until early July 1979, the effort is adequate to validate the model predictions.
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SUMMARY
OF THE M0t1110 RING FFFORT 2.1 Monitoring Perfods A tntal of 29 thermal plume maps were obtained during this monitoring effort, which extended from July 1978 to August 1979.
The actual monitoring periods were August 21 - September 8, 1978 October 30 - December 15, 1978 March 27 - April 6, 1979 July 23 - July 28, 1979 A brief log of the monitoring effort and the difficulties encountered is shown in Appendix A.
The ambient late currents were determined during the periods of June 10 - December 19, 1977 May 6 - December 16, 1978 April 3 - August 19, 1979 And the ambient lake temperatures were measured during the periods of April 29 - December 16, 1978 April 3 - August 19, 1979 All data are summarized in the " Report on the Characteristics of the Thermal Discharge from Donald C. Cook Units 1 and 2,"2 submitted in January 1980 to if the Chief, Water Quality Division, Michigan Water Resources Commission.
In summary, there were no particular delays or difficulties involved in mon-itoring the summer plumes, other than the delays caused when the plants were operating at less than 75% rated power.
A total of eight thermal plumes were mapped during the fall period, even though the ef fort was extended 15 days beyond the scheduled period..The primary dif ficulties were related to bad weather and the plant's operating at less than 75% of rated power.
The shut-down of Unit 2 for maintenance terminated the winter effort.
In general, the weather becomes a more significant problem during late fall and winter periods when the air temperatures are lower than the water tem-peratures.
These conditions promote an increased energy exchange between the 3
wind and the water so that a given wind velocity will create larger waves, and more rapidly, than when the air is warmer than the water.
Furthermore, winds out of the north (northwest to northeast) are usually more predominant during the fall and winter. Because of the long f etch for winds from this direction, adverse wave cenditions prevail frequently.
The east shore of Lake Michigan is more dif ficult to work than i<. the west shore because of the predominating wind and wave conditions.
No thermal plume maps were obtained during the winter period because of lake ice.
Monitoring attempts were initiated on March 27, 1979, in anticipation of the dissipation of the 1ake ice.
Ice and weather continued to be a problem during this period until Unit 1 was shut down for refueling.
On the only day that monitoring could N attempted, the monitoring equipment bectme er ratic because of the extreme cold.
No plume maps were obtained during this period.
Both units were down fr* an extended period for refueling and repairs and did not return to 73% of rated power until July 23, 1979.
Ten thermal plumes were mapped during the next five consecutive days to complete the monitoring
-effort.
2.2 Summary of Monitoring Results
-Reference 2 cnntains the thermal plume maps, a tabulation of the ambient lake data, and a summary of the findings of the thermal plume monitoring with two unit operation.
The following summary of the monitoring ef fort is extracted from that document.
Even though all four seasons were not sampled during the plume mapping periods (due to adverse weather conditions and unit outages), it is believed that a representative collection of varying lake current velocities and directions and af varying ambient lake temperatures were observed.
Because of the per-sistence of lake ice, along with the lake snd weather conditions that normally exist during the winter months on the eastern side of Lake Michigan, it is unlikely that sinking plumes, if
- hey am in e3 !stence during this time of year, can ever be monitored.
4
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2.2,1 plume Areas, tiidths, and Volumes The thermal plume areas, widths, and outerlines were determined at a depth of one meter.
The flichigan Water Resources Commission concurred in utilizing the one meter data because it eliminated many anomalous resells produced by solar heating of the surface water.
Twenty.nine plumes were mapped, and these data are shown in Table 1.
The areas within the A3 F isotherm at a depth of 1 meter varied from 21 acres to 740 acrer.
The average area for all 29 plumes was 290 acres.
Three plumes 3
exhibited areas greater than the 570 acres specified in the NPDES permit.
The largest plume, 740 acres measured on September 8, 1478, was obviously transitory in nature.
It was 35% larger than a plume measured only 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br /> earlier.
The increase in the size of this plume, as discussed in reference 2, can be attributed to a change in the ambient temperature during the monitoring period.
A comparison of the ambient temperatura measured during the ambient run with the in situ temperatures shows that during the mapping run the natural lake temperature increased about 2 F above the ari.bient temperature value used in reducing the data.
The other two plumes exceeding the NPOES specification had areas of 655 and 634 acres and were measured on November 3, 1978. These plumes were also transitory in nature and can be attributed to variable current directions and low current speeds.
There was also evidence
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that the recirculation of discharge water was greater than during the previous day (probably because of the low current speeds), and this was a contributing factor to the large area.
The maximum width of the plumes within the A3 f isotherm at the 1 meter depth anged from 984 to 6,724 feet, and the average width for all 29 plumes was 2,765 feet.
The average plume width for each of the three monitoring periods is shown in Table 1.
In general, the width of the plume increased as the area increased; however, the width for any given plume area varied by a factor of two.
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Table 1 Summary of Plume Areas, Widths, and Volumes August-September, 1978 Date 8/23 8/25 8/25 9/5 9/5 9/6 9/6 9/7 9/7 9/8 9/8 Area (acres) 24 193 311 237 80 287 117 336 568 549 740 Width (feet) 984 2394 2362 2230 1148 2165 1673 4100 4838 5642 4264 Volume (acre-ft) 413 2327 2771 1720 1342 1732 1537 1996 4029 3678 4852 Average area 313 acres l
Average width 2890 feet Average volume -
2400+ acre-ft ilovembe r-Decembe r, 1978 Date 11/1 11/1 11/2 11/2 11/3 11/3 11/7 11/7 Area (acres) 154 389 142 200 655 634 294 515 l
Width (feet) 1771 2854 2394 1705 3838 4648 2066 6724
=
l Volume (acre-ft) 2414 3747 1105 1520 5107 5615 2883 4103 Average area 373 acres Average width 3150 feet Average volt.=e -
3323+ acre-ft July, 1979 Date 7/24 7/24 7/25 7/25 7/26 7/26 7/27 7/27 7/28 7/28 Area (acres) 297 450 109 161 149 269 30 21 171 342 Width (feet) 2034 3182 2296 3116 1804 2821 918 886 2524 2755 i
Volume (acre-ft) 2363 3295 951 1551 1190 1625 540 173 1494 2412 Average area 200 acres Average width 2244 feet Average volume -
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l The volumes of water within the 63"F isotherm regions are also summarized in Table 1 for the three monitoring periods.
The volumes of water r,inged f rom 173 acre-feet to more than 5,615 acre-feet.
The average volume for all 29 plumes was 2,300+ acre-feet.1 i
2.2.2 plume Thichng l
Of the 29 plumes monitored, approximately 70% showed no A3 f water at depths below m ters.
The remaining 30% showed relatively small a.eas of A3"f water i
at the ineter depth, with most of these deeper plumes occurring dur ng the tiovember monitoring period.
1he plumes, in general, were relatively thin, i
I most of the warm water being in the upper one meter of the lake.
The raajority i-of the plumes exhibited areas at the one meter depth that were less than half j
the surface area. In addition, the areas at the two meter depth were usually i l smaller by a factor of two or more than aere the areas at the one meter depth.
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l 2.2.3 Centerline Temperature Decay 4
lll Temperature decay along the centerline of the plumes was analyzed by plotting I
the difference between the plume temperature and the ambient temperature, at a I.
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depth of one meter, versus the centerline distance from the discharge structures.
These data are shown on Figures 1, 2, and 3, which correspond to
& separate monitoring periods.
Comparison of the data in Figures 1 and 3 shows similar trends for the summer periods (August - September, 1978, and July,1979).
The higher excess tem-perat tres decayed quite rapidly unti'. they became 4 to 5 F above the ambient.
At that point the temperature decay rate became much more gradual.
It can be seen from these figures that the 63 F isotherm may terminate anywhere from 1,310 feet to 11,810 feet from the discharge.
i 1The + iuplies that the surface areas and volumes were actually larger than the stated value by an amount associated with the surface area that was out-
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The initial rapid dec w rate during these two periods can he attributed to the relatively high discharge veloci ies that entrained the adjacent lake water.
Because of stratification, the entrained water temperature was normally lower 1
than the ambient temperature at one meter.
lhe resulting mixing caused the rapid cooling.
As higher velocities and resulting turbulence dissipated, the
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discharge waters began to stratify, and the rate of temperature decay became more a function of the ambient lake turbuler.cc and the atmospheric heat dis-i sipation.
1 The gravitational forces associateu with buoyant warm water tend to inhibit vertical mixing with cooler, less buoyant ambient water.
lhe amount of am-bient lake turbulence, which is a result of energy imparted to the lake by the sun, wird ferces, and Coriolis forces associated with the earth's rotation, determines just how f ast this warmer water sill mix with the cooler water, lhe turbulence is a major f actor in determining the horizontal rate of civ.ing and spreading of the plume.
And when the turbulence level is suf ficient to l
uvercome the buoyant forces, it promotes vertical mixing with the cooler water below.
The warm water on the surface also gives up some of its thermal energy to the atmosphere by convective, evaporative, and radiant heat transfer.
Tb" data shown in figure 2 represent that obtained during the llovember 1978 monitoring period.
In this case, it may be seen that the higher temperatures decayed over a greater distance than during the earlier seasons.
This is l
attributable to the lake having been well mixed; i. e., it had a more uniform I
tempnrature vertically than during the earlier seasons.
During this time of l
year, when there are no stratificatico ef forts, the water leaving the dis-c %rae structure is mixed with water having essentially the same temperature the 'mbieat temperature at the one meter level.
During earlier seasons, me
- however, 1he stratification process allows water that is colder than the ambient t(iperature at the one meter level to be mixed with the discharge I
water, thereby cooling it more rapidly.
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When compared with the data obtained from Unit 1 operation alone, the maxinum 4
excess temperatures observed at the one meter level were 3-4"f higher during i
the two unit operation, The pattern of higher temperatures being observed at a given distance f rom the dischargo during the f all and winter months, when the lake was well mixed, was also observed in the data from Unit 1 operation.
4 11 2
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2.2.4 S_easonal Variation 3 The data for the 29 plumes indicate that the average areas, widths, a r.d i
volumes did show seme seasonel variation.
This was true even through there was considerable variation in plumes ftom day to day, and even during the same day, fer any given monitoring period.
It may be seen f rom lable 1 that the parameters listed increase from the early summer period to the late summer period to the fall period.
A similar offcct was observed in the Unit I i
monitoring offort4 It is believed this offect can be attributed to the
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seasonal difference. in the stratificalion characteristics of the lake.
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With stratified c.onditions existing, the temperature of water entering the circulating water intake structures is normally lower than the ambient water temperature at the one meter level.
This results in the condenser dischrge water being cooler, with respect to the one meter depth ambient temperature, than it is in the itnstratified condition.
The plume size is therefore smaller than in the unstratified situation.
This ef fect was f airly evident during 4
the Unit I studies.
The plun.e sizes during the monitoring of the two units were occasionally influenced by the apparent recirculation of discharge water, which was seldom observed during the Unit 1 operation alone.
The recirculation of warmer water into the intakes raised the condenser discharge temperatures, relative to the one meter ambient temperatures, and created larger plume: than when there was no recirculation.
It is felt that the combination of stratification ef fects with variable and transitory recirculation was responsible for the wide range in plume sizes observed in any given period.
It must be noted that the data collected during this monitoring ef f ort were obtained on relatively calm days, days during which the wind and waves were not severe enough to prevent use of the boat and monitoring equipment.
During days when lake conditions were seveie, the sizes of the thermal plumes would be expected to be smaller, on the average, than those reported in this study.
This is because the increased turbulence in the lake, produced by the inten-sified wave action, would promote mixing and dissipate the plume more rapidly.
12
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- 2. 2, 5 Areas of Influence The plume maps obtained during this monitoring et f ort were utilized to define the region of the lake, at the one meter depth, that was occupied at one time er another by water with a temperature more than 3"f above the ambient water temperature.
This region is shown in figure 4.
Areas have been shaded to portray the percentage of piume maps having specific locations influenced by the A3 f water when Units 1 and 2 were both operating at 7b% f ull power or more.
The skewing of the shaded areas to the north of the plant is the result of the predominantly north-flowing currents observed during the monitoring periods.
2.3 Ambient Conditions The ambient lake temperatures and currents were observed to be extremely variable and apparently had significant effects on the thermal plume behavior.
Ambient lake stratification had a definite impact on the plume size.
2.3.1 pmbient Lake Temperature Lake temperatures were measured in the vicinity of the D.
C.
Cook Nuclear 4
plant by means of vertical arrays of thermistors and in-situ temperature recorders anchored on the lake bottom.
Three temperature recorders were otilized-one north, one south, and or,e west of the discharge area.
An example of the lake temperature data is shown graphically in figures 5 and 6.
This representation illustrates the extreme variability of the natural lake temperatures as a function of depth.
The plots show the daily maximum, minimum, and average temperatures, and the dashed lines show plus and minus one standard hviation.
These variations, measured in the vicinty of the l_
Donald C.
Cook Nuclear plant, showed magnitudes of temperature changes that i
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exceeded temperatures associated with the Cook Plant's thermal discharges.
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For instance, changes of more than 20 f were seen occurring from one day to L
the next over the region of the lake monitored by the recorders.
This re-presented a rate of change of the energy content of the water in this same q
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region that far exceeded anything that the Donald C. Cook Nuclear plant could produce.
Individual temperature sensors regularly recorded daily temperature variaticas of more than 10 F.
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1.al e Temperature 1)ata
( 6/P2/7D-8/20/710 16
l These natural temperature variations.nal the tpatial and temporal variations in late currents make it irnpossible to predict what a plume might do from one day to the next.
These natural variations, hawever, are evidence of the dynamic natural processes that exist in the late and t hat can be expected to disperse and dissipate the Cook Plant thermal discharges.
I A reality of thermal plume monitoring on a large lake like Lake Michiyan is the virtual irrpos s ibili ty of defining a single ambient temperature.
As graphically illustrated by the in-situ data (figures 5 and 6), the natural temperatures vary both spatially and temporally in the area near the power plant.
The ambient tenperatures used in reduciq the data f rom this study were defined as the average of all temperature readings obtained during the
" ambient run."
(The " ambient run" consisted of rnea sur i ng the water tem-peratures at various deptba during a shore perpendicular transect in the region up current f rom the discharge area. )
A review of the data in ref er-l l
ence 2 shows that at times this involved averaging data with a spread of more than 2 f.
This spread in the ambient temperature' data represented primarily spatial variations and did not reflect the temporal variations.
The ambient temperature utilized in reducing of the data can have a signifi-cant ef fect on the size of the area within the A3"f isothern, as a review of the data related to the 740 acre thermal plume measured on September 8,1978, shows.
For example, if the ambient temperature were actually lf higher than that utilized for reducing the data, the plume area would be reduced f rom 740 acres to.113 acres.
for this particular plume, the data averaged to evaluate the ambient temperature showed a spread of 1"F.
In addition, the in-situ temperature recorder on the up-current side of the plume indicated an ambient temperature approximately 1f higher than that determined by averaging the
" ambient run" temperatures.
A 0.5 f chango in the ambient temperature used to reduce the data would have changed the plume area several hundred acres.
Tersporal and spatial variations of the ambient temperature in the near shore waters of lake Michigan of ten result f rom upwellings, f rom vertical n'otion of the thermocline produced by internal waves, and from solar heating.
Upwel-lings are produced in a stratified late when a strong, persistent wind drives 17 maammmm
__ __ ~.........
l I
the warm surface water to the downwind side of the late and " tilts" the thermo-cline suf f iciently to cause the colder water below the thermocline to come to the surf ace on the upwind side of the late.
This results in measured ambient temperatures that increase with distance of f shore.
Internal waves (vertical motions of the thermocline produced by gravitational and Coriolis forces) create temperature fluctuations as a function of time at any given measurement location as the thermocline moves above and below the sensing instrument.
Solar heating results when solar energy is absorbed by the water nass.
Most of the energy is absorbed near the surface, causing the temperature to in-crease in a relatively thin layer.
The remainder of the energy is absorbed in the water column to the depth of penetration, which is a function of the purity of the water.
Since the solar energy input is uniform over the surface of the lake, the shallow, inshore, and of ten more turbid water receives more energy per unit volume and is thereby warmed more rapidly than is the offshore water.
In this case, the measured ambient temperature would decrease with distance offshore.
Solar heating also results in variations of the ten-perature with time.
Temperature increases of 5 F within a two hour period have been observed in the top one foot of water on a hot, calm summer day.
Water warmed by solar heating cannot be dif forentiated from water heated by the power plant.
Thus, when there is significant solar heating of the sur-face, it becomes very dif ficult to (1) define an ambient surface temperature because of large temperature variations, and (2) to define the boundaries of the thermal plume at the surface.
These natural phenomena, which result in ambient temperature variations, cannot be modeled in a hydraulic modeling facility.
Tho hydraulic modeling is done with water at a uniform temperature.
2.3.2 Ambient take Currents l
The single most important physical parameter affecting the position and trajec-tory of the thermal discharge is the ambient lake current in the vicinity of l
the discharge.
The current also af fects the size of the discharge plume, but this ef fect was masked by size variations induced by stratification and re-circulation.
Four current meters were used for this study of ambient lake currents--two near shore and two offshore.
i 18
lhe graphical representation, of current speed and direction (figures 7 and 8) were used to compare current speed and direction for the various meters, lisually, the current speed plots exhibit the same general trends for all f our meters.
Even better correlation exists between the current speed trends for the two inshore meters and for the two of f shore meters.
While the overall trends agree, significant dif ferences in current speeds of ten occurred at any given time.
In other words, long-term trends in current speed show some consistency at the four monitoring locations, but short-term local current speeds show considerable variation.
The plots of current direction show very poor correlation f rom one current meter to another, for instance, for the period flovember 17-19, 1977 (Julian dates 321 to 323), the northern offshore meter indicated north-northeast flowing currents; the northern inshore n.eter showed currents flowing to the southwest; the southern offshore meter recorded current directions varying from the northwest to the north-northeast; and the southern inshore meter indicated northwest flowing currents that occasionally shif ted to the north-k east.
For the period flovember 29, 1977, to December 19, 1977, the northern inshore and of fshore current meters recorded current directions that dif fered by 105 degrees or more over 50 % of the time.
Not shown on these plots is the correlation between the r.urface currents, as measured by drogues, and the currents measured by these meters at depths of 11 and 22 feet.
As discussed in the descriptions of the various plumes, there 2
were many instancer, when the surface currents and bottom currents were flowing in different directions.
The two drogues also exhibited dif ferences in the near shore and of f shore surf ace current direction, once showing the two sur-face currents flowing in opposite directions.
These variations and dif f erences in the currents, both temporal and spatial, serve to highlight the complex and unpredictable flow regimes that exist in the near shore waters of Lake Michigan.
Attempts to obtain meaningful correla-tions with the meteorological data were unsuccessful, since there was often no correlation between the various current measuring devices, 19
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lhe plots of current direttlon, similar to that shown i n i igures / and 8, were used to determine current directional persistence data for the three years that the currents were measured.
An example of those data (see i igure 9) shows the percentage of time (based upon recorded data) the lake currents flow in a given direction for a given number of days, figure 9 also shows that the directional persistence of less than one day occurred under 28% of the time f or all but the northern inshore location, where it occurred b5% of the time.
persistence of more than two days occurred 77% of the time at the north of fshore locations, $3% of the time at the south offshore location, and 21 and 47% of the time at the northern and southern inshore locations, respectively.
The north flowing currents were only slightly niore persistent than the south flowing currents at the southern locations, and the probability of north or south flowing currents was about equal at the northern locations, lhe data f or 1979 generally showed more persistence than did the data f rom the previous two years, lhe surface currents during this monitoring of fort indicated north flowing currents for 67% of the measurements, south flowing currents for 29% of the measurements, and east flowing currents for 5% of the measurements.
This sample of surface currents was probably biased by winds from the northwest through the northeast, because these winds, which produced south flowing surface currents, also produced larger waves that might well have prevented the boat from going to the plant to make the measurements.
The temporal and spatial variations in lake currents measuren near the D. C.
Cook site are the result of complex eddying motions, covering a wide " spectrum of eddies. "
Such motions are associated with the turbulent flow conditions that almost always exist in large lates.
The state-of-the art of mathematical modeling is not adequate to allow prediction of the micro-effect of eddies at a given location.
Similarly, hydraulic models, although designed to produce turbulent flow in the simulated lake water, cannot adequately model the spec-trum of eddies observed in the lake.
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2.3.3 Stratification lhe effect of stratification, as indicated in section 2.2.4, appears to be the primary f actor influenc ng the plume size.
Since stratification is seasonal, i
this produces the seasonal variations observed during both monitoring of forts (Reference 2 and 4).
The lake bagins to stratify in spring as the rate of solar heating begins to increase.
During this time, tha layer of warm water on the surf ace is rela-tively thin, and thus the condenser cooling water, which is discharged near the lake bottom, can entrain more cold water before it reaches the surface than when the thermocline is at greater depths.
This res'.'lts in the smaller l
plumes that are observed during the spring.
"flegative plumes" (plumes in which the water is cooler than the ambient water)' were observed during the first monitoring offorti.
As the solar energy input to the lake increases during late spring and summer, the stratified layer of warm water becomes thicker.
Under these conditions, the intake water temperature is still considerably cooler than the ambient temperature at the one meter depth, llowever, the condenser cooling water is now entraining and mixing with more of the warm water in the stratified layer, thereby increasing the size of the area within the A3"T isotherm.
When the stratified layer in the lake is deep enough to surround the intake structures, the temperature of the water entering the condensers is consequently warmer, and the difforential temperature between the condenser discharge water and the ambient :
ature is greater.
This condition occurs during the f all and i
produces the largest plumes.
These conditions, i.e.,
relatively uniform temperatures between the intakes and surface, are the conditions that were simulated in the hydraulic modeling of this dischargo.
i 24
_A
- 3. O
SUMMARY
Of MODI'l !!G II f OR1 The once-through circulating water system for the D. C. Cook Plant utilites an offshore, submerged, horizontal jet-type discharge structure for each of the two units.
The thermal plume which evolves fiom these discharge structures may be characterized by three flow regimes.
1he "near-field" region of the thermal pitane is that region where the plume is well defined and the velocity of the water in the plume is still signitIcantly greater than the ambient water body velocity.
This velocity dif f erence he-tween the plume and ambient water body produces considerable turbulence and entrainment that results in lateral and vert.ical spreading of the plume.
1his induced mixing is enhanced to a lesser degree by the ambient water body tur-bulence.
A " transition region" occurs when the ambient turbulence approaches or exceeds the jet-induced entrainment as an important mechanism in the dilu-tion proces ;.
Ultimately, at. a suf ficient distance f rom the discharge, l.e.,
the " f a r-fiel d," the excess jet velocity is dissipated, and the plume is advected in the direction of the ambient current.
Diiution in the f ar field is controlled by ambient turbulent dispersion.
i 3.1 llydraulic Motjel, Estimates of the excess temperature distribution within the near-field and the transition region between the near and f ar-f ield were obtained from a by-draulic model study performed by Alden Research laboratories of Holden, Massachusetts.
A large and elaborately detailed hydraulic model was used to simulate the near-field, jet-induced entrainment.
This enabled an accurate simulation of the interaction of the discharge plu:nes f rom the two multi-jet structures with each other and with the lake boundaries, lhe Sydraulic model was designed on a scale ratio of 1:75 f or both the vertical and horizontal dimensions.
The nodel utilized prototypal ef fluent and ambient water tem-peratures and timulated the dynamics of the interaction between the discharge jets and the ambient lake current.
The model basin was approximately 100 by 47 feet, thus representing a portion of l ate Michigan measuring 7500 feet along the shoreline and 3500 feet out into the lake, t.ake bottom contours were t eproduced in the model with templates having prof iles at any section geometrically similar to those at the corresponding section in the lake, 2b
]
l 1he model had two water flow systems; one for simulating late flow and the other f or signulating poner plant f lows, for lake flow, water was pumped from a sump through a flow distributor onto one end of the inodel basin and allowed to flow out at the other.
flow rate to the Inodel was measured by s venturi rneter in the supply line to the flow distributor and was controlled by a valve downstream of the venturi meter.
Water level in the model basin was con-trolled by weirs at the downstream end of the basin.
The temperature of the l
water flowing into the basin from the flow distributor was governed by the ternperature of the water in the sump.
lhe latter temperature was adjusted by mixinq hot and cold water, i
The power plant once-through condenser cooling water system was simulated by a system consisting of intake piping and structures, discharge piping, and a mixing tank.
The intake and discharge piping for each unit was fitted with orifice meters and valves for measuring and regulating the flow into and out of the mixing tank.
Simulation of power plant operation consisted of setting the dic. charge flow on each unit equal to the intake flow on each unit and mixing the intake flow with the amount of hot water needed for a given temperature rise.
A portion of the mixture equal to the amount of hot water added was allowed to flow to waste.
Temperature measurement and recording in the model was by a network of thermo-couples connected to a data logging system.
There were 137 thermocouples in the n
-ork, plus two thermocouples in each of the intate and discharge struc-tures # d three thermoccuples immediately downstream of the flow distributor.
These thermecouples were f or measuring the temperatbre of the ambient water upstream of the power plant, and there were additional thermocouples for measuring air wet and dry bulb temperatures and pump temperatures.
3.2 Mathematical liodels The excess temperature distributions for the f ar-f ield were obtained by the use of the hydraulic model data and analytical models.
The results of the hydraulic model study were used to initialize a f ar-fielJ analytical model to 26
obtain the excess t empet at ure distribution in the far-field for tioth stagnant and representative late current conditions.
In the stagna t late case, the e>.t rapolation of the near-f ield excess tempora-tures to the f ar-f ield entailed the use of an empirical torrelation by Weigelb f or plume centerline temperature decay.
liy trial and error, an imaginary discharge was defined that would yield a tuatch with the temperatures obtained f rorn t he hydraulic model result s.
Once a match was established, the correia-tion was used to estimate the centerline location of the excess temperature isotherms in the f ar-f ield.
The widt hr. of the f ar-f ield excess tempera;ure isotherms were approximated by inct easing the plume width linearly as a f unc-tion of centerline distance from the discharge, as proposed by $toltenbach and Itarleman.6 lhe appropriate linear growth rate was determined f rom the hydrau-lic model data.
for modeling situaticns involving a late current, an overall centerline tra-jectory was obtained ty averaging the trajectories of Units I and 2.
The complexity of the discharge jet configuration made this necessary.
The center-line trajectories determined by this process compared f avorably with the hydraulic model data.
A second step involved the derivation of a model that would sinalate the decay of excess temperature in the f ar-field under the condition of an ambient curre" lhe analysis used the Sundaram7 model, which assumed the pleme in the f u.1 f eld to be moving along with the same velocity as the ambient late current.
The width of the thermal plume was estimated by assuming the far-field excess temperature to be distributed normally about the plume centerline.
The mathematical f ar-f ield model was then coupled to the near-field and transition regions, as modeled in the hydraulic tests, by assuming that the far end of the last closed excess temperature isotherm was an imaginary outf all whose locatien dimensions, temperature, and f low were obtained directly from the hydraulic model data, i
The results of this analytic technique were f ully reported in ref erences 8 and 9 and are summarized below.
It was noted t hat because the ambient late tur-hulence and heat transfer to the atmosphere were not adequately represented by the mathematical models, the results of these analytic extrapolations of the hydraulic model data would conset vatively overestimate the size of the plume within ihe A3"f isntherm in the far-field region.
27 I
- 3. 3 ljodo I i vyg_lks 01 ti llydraulic model plume data were generated f or two unit s eperat ing.6L full power, for one unit operating at f ull power, and f or one unit operat.ing at 01%
.of full power.
The ef f ects of a raage of ambient late currentr, were studied in each case.
A comparison of the data for one unit operation with the field tau 1 set ement s was reported in the 316(a) Demonstration Report 10 submitted to the M4RC in January, 1977.
figures 10-13 illustrate the results on t he combined bydraulic and anathemat-ical modeling predictions of the plume behavior with both Units 1 and 2 oper-ating at full power.
The figures represent the effect of ambient late current speeds of 0, 0,2, 0.5, and 1.0 fps, respective 1) l The results f rom these studies are tabulated in Table 2 and show that the maximum plume area of 570 acres was observed at a late current speed of 0.2 fps.
It is postulated that this cf fect is the result of the interference the two discharge structures exert upon each other due to the warm water dis-charged from the upstream structure being entrained by the plume discharged f rom the downi.tream structure.
At higher lake current speeds, the ambient lake momentum would suppress the of fect of this entrainment by increasing the amount of cooler lake water available for dilution of the plume.
The zero-current lake condition resulted in some re-entrainment of warmer water but to a lesur extent than in the 0.2 fps current speed test, thereby producing a smaller plume area as compared with the 0.2 fps case.
Table 3 summarizes the predictions of the plune temperature and velocity as a f nction of plume centerline distance from the discharges.
The predicted piume areas, depths, and volume for a late current speed of 0.2 fps are shown in Table 4.
An estimte0 of the dimensions of the lake region that would, at
(
one time or another during the plume's meandering, contain plume water with an excess temperature of 3 F or more is summarized in Table 5.
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{
loble 2 Predicted Plume Areas vs. Lake Current Speeds l
Current Speed Area Within Given Isotherns
{ fps)
(acres)
AS f A4 f A3"f 0
15 135 530 0.2 110 225 570
- 0. 5 95 220 460 1.0 45 85 190 Table 3 Predicted Plume Tenperature and Velocity vs. Distance I
Excess 1
C Distance Temperaturc Velocity g (ft)
@ f)
(fps) 0 19.5 13.0 125
- 10. ('
6.2 400 8.0 2.4 G50 7.0 2.2 1275 G.0
- 1. 6 3000 5.0 1.0 l
441^
4.0 0.65 6600 3.0 0.2 12350 2.0 0.2 29
_ _ _ _ - _ = _ _ = _.
_x
I Table 4 I
Predicted Plume Areas, Depths, and Volumes l
Excess Volume Temperature Area 8etween Excess Plume +c nb
% me Depth (avg. summer Isotherms Temperature Isotherms (suacv) 6Jnter) and winter)
(f )
(acres)
( fi,3R,
[ lt )_
(cubic feet) 10 and 7 6.6 11.c 1 J. 5 3.9 x 106 7 and b 128.0 14.0 28.5 5.32 x 10' 4
148.0 12.0 30.0 6.62 x 107 289.0 10,5 27.5 1.41 x 108 loinLS 571.6 2.64 x 10" Table 5 Predicted Maximum Extent of plume l-(derived from a variety of. current conditions) l Excess Temperature Distance from Discharge Structures
( F)
Ift)
North & South fast West l
l 2
9400 1200 7400 3
6200 1200 5200 c
~
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7 500 00 600 i,
l e
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I 4.0 LOfTARISON Of fillD DAlA \\/IIH phlDIC110NS Comparison of field data with one unit operation, as icport ed in ref erence 10, indicated that the modeling technique described in Section 3.0 was conserva-tive in predicting the plume size and shape.
Twenty eight of the thirty plumes measured had areas considerably smaller than the predicted area.
lhe two plumes with areas larger than that predicted by the models appeared to be influenced by transient conditions in the lake, plant operating dif ficulties (higner condenser Al's because of two pump operation), and some possible recirculation effects.
4.1 p~,jme Areas Simile, re.mth were observed during the monitoring of two unit operation in that 26 m the 29 plumes measured had areas smaller than the 570 acres pre-dicted by tt.a models.
As discussed in Section 2.1 and in ref erence 2, the three plumes larger than the predicted maximum were transitory in nature.
That is, they appeared to result from changes in the ambient lake temperature during the monitoring period and from transient and variable laka currents that probably created some recirculatian of discharge water.
The average area for all 29 plumes was 290 acres, approximately one-half of that predicted by the nodels.
A review of Table 1 will show that the average area of the plumes measured during July (1979) was 200 acres.
The average area for plumes measured in August-September (1978) was 313 acres, and the average area was 372 acres for j
the plumes measured in Novmber-December (1978).
This trend, i.e., the plume
[
area increasing as the year progressed, was also observed during the mon-it oring of one unit.
As discussed in Section 2.4, this ef fect is believed to result from seasonal changes in the stratification characteristics of the lake: As the thermocline goes deeper, the plumes become larger.
The limit to this cffect would be when the lake, or the area of the lake af fecting the L
thermal discharge, achieves a uniform temperature.
A review of the ambient temperaturn data in ref erence 2 shows that this condition existed during t he
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November-December monitoring period.
l
)
31
l The hydraulic scale model usmi to predict the theimal plumes utilized uniform tem;>erature water to siulate the ambient late, it could be expected, there-fore, that the modeling represented the worst case situation.
Since the real lake does not achieve a uniform temperature until late fall, it may he con-cluded that data taken then would provide the most realistic comparison with the models.
l l
It may be seen f rom lable 2 that there is an apparent ef fcct of the current I
speed on the plume size.
However, close examination of the data listed on Figures 10 13 suggest another potential explanation of the variation in plume area.
It may be seen that for current speeds of 0 and 0.? fps the intake temperatures are
- 1. 5 to 2*F higher than the ambient temperature, probably because of recirculation, lhus, the larger plumes observed in the models at the lower current speeds may have been more the result of the recirculation ef fect than of the current speed ef fect, if this were the case, the modeling results could be said to have produced a more realistic simulation of the actual conditions than one would conclude by assuming that the current speed effect was the major parameter.
I 4.2 Centerline Temperature Decay Rate J
)
Table 3 shows the predicted centerline distances from the discharge of the various excess temperature isotherms.
These data are plotted on Figures 14, 15, and 16 to show the can'parison between the field data and the predictions.
It may be seen on Figure 14 that the model predictions tend _to over estimate l
the distances that the various isotherms would exist from the discharge.
In 1
i other words, the plume temperatures tend to decay more rapidly during this j
period than predicted by the models, figure 15 shows that the model predic-
]
tions similarly predict greater centerline distances for the isotherms than were observed by the field measurements, though not to the same degree as those measured earlier in the year.
It. is interesting to note that the large 740 acre plume, measured on September 8, 1978, (designated by the arrowhead) exhibited a temperature decay rate that was greater than the predictions, except at the 63 F isotherm.
In other words, the area hetween the 63 and a4"F isotherms was inordinately large compared to the rest of the plume.
Figure 16 shows that the centerline temperature profile for the November period was predicted fairly well by the models.
The higher excess temper-32 h
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I 39
atures persisted somewhat farther than the model predicted, while the lower excess t emf. erat ures did not persi<,t quite as f ar as t he model predicted.
This is particularly true if the twr, 600+ acre plumes helieved to be transitory in nature, measured on November 3, are discounted.
Again, in view of the fact that the lake conditions existing during the plume monitoring in November 19!8 most closely approximated the hydraulic model conditions, it may be concluded that the modeling results were confirmed quite well by these data, l
4.3 Plume Depths
+
The modeling results shown in Table 4 indicate a predicted plume depth ranging from 105 to 14 feet in depth during the summer months and 16 to 30 feet deep during the winter.
Approximately 70% of the field data showed little or no A3 F vater below the 10 foot depth.
Most of the plumes axhibiting the 63 F water at the 13 foot depth were measured during the November monitoring period.
Since the November conditions most closely approximated tiie con-ditions ir, the hydrauiic model, it may be concluded that the model did e good job in predicting the plume depth.
Earlier in the year, however, the field p
data indicated plumes that were not quite as deep as predicted by the model.
No data were sbtained to allow comparison with the predicted winter plume thickness.
l l
l 4.4 plume Volume i
jl
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T ab l t: 4 shows that the models pre..cted an average volume of 2.64 x 108 cubic l
feet (or 6,060 acre-ft) for the plume.
This volume was calculated assuming a plume depth of 10 feet and also assuming a constant plume area at all depths.
'1 The average volume of the plumes measured in the field during IPvember was 3323+ acre-ft, little over half of the predicted volume.
The discrepancy i
between the predict. ion and the field data could be explained by the fact that the predictions assumed a consiant plume area as a function of depth. The field data indicated that the crea decreased with depth, and an allowance for i
this factor would have reduced the predicted volume.
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4.S Region of Influence lhe modelinb and analytical results were used to e n.
.te an area of influehte of the therinal discharge.
The data tabulated in lable 5 were used to calcu-late an oval-shaped envelope representing the area of the late that would he influenced at one tima or another by the A3"f water during the plume's ineandering and f1' actuation.
An approximate oval of these dimensions was superitaposed on l'igure ? to compare it with the region of influence observed during the field studies, inis is shown in f igure 17 f or the one tacter depth.
The measured area of influence extended further of fshore and to the north than predicted by the modeling.
This result was also observed in the monitoring of l
the one unit operation.
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SUMMARY
- Data from the _in-situ temperature _ and current recorders showed a large vari-l ability in the natural temperatures and currents in the lake near the Donald C. Cook site. The natural temperature changes represent a rate of change in the energy content of the _ water that f ar exceeds anything the Donald C. Cook Nuclear plant could produce. The variability in the currents are the result of complex eddying motions that, along with the natural temperature varia- ] tions, are practically impossible to simulate in a hydraulic model. p A-comparison of the -predictions of plume size and location with the data a obtained during the monitoring program showed that, with the exception of the j three transitory plumes, the models predicted areas larger than were observed in _ the ficid. The prediction of the excess temperature profile along the plume centerline showed relatively good agreement for the plumes measured in_ i November (when the lake temperature was relatively uniform), However, the - models _ over predicted the excess temperature as a function of distance from the discharge during the earlier monitoring periods. The prediction of the-plume depth agreed well with the data, but the predicted volume was almost twice 'as great as the observed voluma. Although the observed volume was smaller than the prediction, the obso.ved region of influence of the A3'T . water was somewhat larger than the predictions, Conditions -in the lake during the late fall monitoring periods most closely approximated the uniform temperature: conditions utilized in modeling the ther-mal _ plume. The__ conditions during late fall also produced the largest plume areas _because the intake water temperature is essentially the same as the ambient - water temperature used to define __ the excess temperature isotherms. (Stratification ef fects_ that occur earlier in the; year cause: the intake water to be -~ cooler than the-ambient water temperature. This results in a smaller - temperature difference between the discharge water and the ambient temperature-and therefore ' produces a smaller plume.) Tnis same condition of relatively 1 uniform _ lake _ temperatures persists _ during the winter and until the spring - warming--and the beginningl of stratification--starts in late March or early - April. Therefore, it is felt that this' monitoring ef fort, even though it was unable to monitor plumes during the February-March period and during the i 43
Ap r.i l-loay period, has provided adequate data for validating the modeling techniques utilized for the D. C. Cook plant. And it has provided plume data during the time when the plume would he expected to be the largest. i lt is highly unlikely that measurements of the thermal dischargo during the f winter months can be made at the Donald C. Cook plant. The adverse weather and lake conditions existing during the winter, the accumulation of ice, the unavailability of boats during that time of year, along with general safety considerations, render it virtually impossible to obtain winter plume data. Plume meawnments during the spring season will also be almost impossible to obtain, since planned maintenance schedules will have one or both of the units [ down during this period. It is further felt that data obtained during this ] J time of year are of little significance with respect to comparison with the modeling data because of the stratification effects. As the smallest plumes occur during this time of year, the data are also of little significance with respect to validating the allowable area specified in the NPDES permit. l 0 I i s t J [ l 44
6 REFERENCES 1. U. S. Atomic Energy Conmission, Directorate of Licensing, Appendix B, " Environmental lechnical Specifications for Donald C. Cook Nuclear Dlant, i Units 1 and 2 Berrien County, Michioan, Docket No's. 50-315, and 50-316," October 25,19/4 - Amended November 8, 1978, by Nuclear Regulatory Com-mission, " Amendment No. 26 (Unit 1)/ Amendment No. 8 (Unit 2)." 2. Indiana & Michigan Power Company, Donald C. Cook Nuclear Plant, Units 1 & 2, " Report on the Characteristics of the Thermal Discharge from Donald C. l Cook Units 1 & 2, Volumes 1 and 2," submitted to Chief, Water Quality l Division, Michigan Water Resources Commission, January 1980. ] 3. Chief Engineer, Michigan Water Resources Commission, " Michigan Water Resources Commission Authorization to Discharge Under the National Pol-b,f . 'l M ) /. lution Discharge Flimination System," Permit No. MI 0005827, December 7, 1974. '*J' }'. 4. Indiana & P' .er Company, Donald C. Cook Nuclear Plant, Units 1 a A. Y and 2, "Rept .ne Performance of Thermal Plume Area Measurements, fi z Volumes 1 and _," submitted to Chief Engineer, Michigan Water Resources h.c (d i, I Commission, June 1, 1976. j p iy - 5.
- Wiegel, R.
L., I. Mobarek, and Y. Jen (1964), " Discharge of Warm Water d. Jet Over Sloping Bottom," Technical Report HEL 3-4, Inst, of Engineering Research, Univ. of California, Berkeley, Calif., Nov. 1964. s 6. Stolzenbach, K., and D. R. F. Harleman (1971), "An Analytical and Experi-g mental Investigation of Surface Discharges of Heated Water," M.I.T., H Hydrodynamics Laboratory Technical Report No. 135, Feb. 1971. q 7. Sundaram, T. R., C. C. Esterbrook, K. R. Piech, and G. Rudinger (1969), "An Investigation of the Physical Effects of Thermal Discharges into Cayuga Lake (Analytical Studies)," CAL No. VT-2616-0-2, Cornell Aeronau-g tical Laboratory, Inc., Nov. 1969. 8. Testimony of J. J. Markowsky, Ph.D., before the Atomic Safety and Licen-sing Board in the Matter of Indiana & Michigan Electric Co. and Indiana and Michigan Power Co. (D. C. Cook Nuclear Plant, Units 1 and 2), Docket Hos. 50-315 and 50-316, feb. 11, 1974. 9. Indiana & Michigan Power Co. (1975), " Plan of Study and Demonstration Concerning Thermal Discharges at the Donald C. Cook Nuclear Plant," sub-mitted to the Michigan Water Resources Commission, April 7,1975) (pp. E 88-120). 10. Indiana & Michigan Power Company, Donald C. Cook Nuclear Plant, Units 1 and 2, " Report on the Impact of Cooling Water Use at the Donald C. Cook Nuclear Plant," submitted to Chief Engineer, Michigan Water Resources Commission, January 1, 1977. 45
I~ APPENDIX
SUMMARY
Of THE MON 110 RING PERIODS The log of the monitoring ef fort involved in this study is summarized below. It recounts some of the difficulties encountered in performing this monitoring effort on Lake Michigan, particularly during the colder months. 4 g..A August 21 - September 8, 1978 nitoring of the thermal discharges from both Unit 1 and Unit 1, with both Its operating at greater than 75% full power, was initiated on August 21, -7 8. Eleven plumes were mapped on six different days. bi Aug. 21 - Installed monitoring equipment on the boat. Boat ,.y generator failed and required repair. Serviced I current meters and temperature recorders. q-Aug. 22 - No monitoring. Unit I at 40% power, Unit 2 down. Calibrated intake and discharge thermocouples at the plant. Aug. 23 - Mapped 1 plume. Sky clear and sunny. Lake changed from light chop to glassy. Aug. 24 - No monitoring. Plant was down for the day. Worked on equipment. Aug. 25 - Mapped 2 plumes. Sky overcast, foggy in the morning; light wi'id, 1-3 foot swells. Aug. 26 - Plume mapping attempt aborted af ter Unit I tripped early in the run. Aug. 26 - Sept. 4-Unit 1 down. Sept. 5-Mapped 2 plumes. Sky clear and sunny, light wind, lake calm. Sept. 6-Mapped 2 plumes. Sky partly cloudy then clearing, moderate breeze, 2-4 foot swells. Sept. 7-Mapped 2 plumes. Sky sunny with haze, light wind, 1-2 foot swells with chop. Sept. 8-Mapped 2 plumes. Sky sunny and clear, light wind, 2-3 foot swells with chop. 46
s Y October 30 - Ik.cember 15,19/8 J Monitorire; of the thermal discharge during the fall season was begun on L October 30, 1978. Eight plumes were mapped on four days early in llovember. Weather conditions or plant operating conditions prevented additional plume mapping until the of fort was terminated on December 15. { Oct. 30 - Installed equipment on beat and checked its operation. Gale warning prevented monitoring attempt. Serviced current meters and temperature recordings. Oct. 31 - Aborted monito ..g attempt because of high winds and waves and failure of the generator on the way to the plant. Calibrated intake and discharge water thermo-couples at the plant. flov. 1-Mapped 2 plumes. Sky sunny and hazy, light wind,1-2 foot waves. l Nov. 2 - Mapped 2 plumes. Sky sunny with haze, 1-3 foot waves I with whitecaps. Nov. 3 - Mapped 2 p'umes. Sky sunny with some haze, light wind, 1-2 foat waves. Nov. 4 - No monitoring. Unit 2 at 60% power. I Nov. 5 Unit 2 at less than 75% power. ? Nov. 7 - Mapped 2 plumes. Sky had rattered clouds, no wind, lake flat. Nov. 8 - No monitoring. Wind blowing at 25 - 30 mph, 4 foot I waves. Nov. 9 - No monitoring. Lake too rough--4 foot waves with l whitecar Nov. 10 - tio morJ toring. Unit 2 shut down f or scheduled niain-tenance. Nov. 27 - No monitoring. Boat had engine problems. Unit 2 at 60% power. Lake was rough. flov. 28 - Moved equipment to another boat. flo monitoring. Wind 17 - 25 mph, 4-6 foot waves. l fiov. 29 - flov. 30 - Bad weather. On standby. I 47 t
l Dec. 1 - Monitoring attempt aborted because of l'igh wind and waves. I Dec. 2 Bad weather. On standby. Dec. 7 - Monitoring attempt aborted af ter Coast Guard warning of high winds, i Dec. 8 Bad weather. On standby. Monitoring ef fort aborted. March 27 - April 6 l The winter season monitorina ef fort was delayed until March 1979, because of heavy lake ice and a frozen St. Joseph Ri'.er. No mnnings were obtained because of bad weather prior to an extender: Unit 1. Mar. 27 - Lake and mouth of river blocked by ice. Mar. 28 - Large quantities of lake ice. Mar. 29 - No monitoring. Lake ice. Boat engines being repa red. -Mar. 30 - Monitoring effort aborted because of ice floes at river mouth, m Mar. 31 - Apr. 3 - On standby, waiting for ice to clear. Apr. 4 - Monitoring attempt aborted at the plant af ter data system became erratic because of the cold. Apr. 5 - Monitoring effort aborted on way to plant because of increasing winds and waves. Winds gusting to 80 mph that night, 15 foot waves on lake. Apr. 6 - Winds still gusting to 30 knots, Unit 1 tripped, would be down for refueling until May 30. Monitoring effort terminated. July 23 - July 28, 1979 No monitoring was performed during the April 15 - May 15 period because the two units were down for refueling and repairs for an extended period. Both units were not at 75% power until July 23, 1979. Eleven plumes were subse-quently mapped during six consecutive days. 48 l ________===__-_:-__ = :_ = __= = ___ = ~ - = = -
9-( l July 23 - Mapped 1 plume (practice run). Unit 2 at 60% power. ,1uly 24 - Mapped 2 piumes. Sky was cloudy. Lake had 2 foot
- waves, July 25 -
Mapped 2 plumes. Sky was cloudy. Wind 12-20 mph, 1-2 foot waves. July 26 - Mapped 2 plumes. Sky sunny and clear, NW wind, 2-5 foot waves. July 27 - Mapped 2 plumes. Sky sunny with light haze, light wind, 1-2 foot waves. July 28 - Mapped 2 plumes. Sky cloudy, slight drizzle, light wind,1-2 f oot waves. Appeared to be strong current to north, r, Y i L F L I P L r L I 49 m -}}