EPA-660/2-73-016
October 1973
Environmental Protection Technology Series
Reviewing Environmental Impact
Statements - Power Plant Cooling
Systems, Engineering Aspects
01
National Environmental Research Center
Office of Research and Development
U.S. Environmental Protection Agency
Corvallis, Oregon 97330
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RESEARCH REPORTING SERIES
Research reports of the Office of Research and Development,
U.S. Environmental Protection Agency, have been grouped into
five series. These five broad categories were established to
facilitate further development and application of environmental
technology. Elimination of traditional grouping was consciously
planned to foster technology transfer and a maximum interface
in related fields. The five series are:
1. Environmental Health Effects Research
2. Environmental Protection Technology
3. Ecological Research
4- Environmental Monitoring
5. Socioeconomic Environmental Studies
This report has been assigned to the ENVIRONMENTAL PROTECTION
TECHNOLOGY series. This series describes research performed
to develop and demonstrate instrumentation, equipment and methodology
to repair or prevent environmental degradation from point and
non-point sources of pollution. This work provides the new or
improved technology required for the control and treatment of
pollution sources to meet environmental quality standards.
EPA REVIEW NOTICE
This report has been reviewed by the Office of Research and
Development, U.S. Environmental Protection Agency, and approved
for publication. Approval does not signify that the contents
necessarily reflect the views and policies of the U.S. Environmental
Protection Agency, nor does mention of trade names or commerical
products constitute endorsement or recommendation for use.
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EPA-660/2-73-016
October 1973
REVIEWING ENVIRONMENTAL
IMPACT STATEMENTS -
POWER PLANT COOLING SYSTEMS,
ENGINEERING ASPECTS
by
National Thermal Pollution Research Program
Pacific Northwest Environmental Research Laboratory
National Environmental Research Center
Corvallis, Oregon
Program-Elements 1BA032 & 1BB392
For sale by the Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402 - Price $1.35
NATIONAL ENVIRONMENTAL RESEARCH CENTER
OFFICE OF RESEARCH AND DEVELOPMENT
U.S. ENVIRONMENTAL PROTECTION AGENCY
CORVALLIS, OREGON 97330
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ABSTRACT
This report describes the approach and technical base that have been
used by EPA's National Thermal Pollution Research Program for reviewing
those portions of Environmental Impact Statements (EIS's) relative
to the engineering aspects (including economics) of cooling water
systems for thermal power plants. The report provides techniques
and data to enable the EIS reviewer to make sound judgments concerning
the adequacy of both the cooling water system selected for the power
plant and the EIS comments on that system. Literature citations are
provided to direct the reviewer to additional and more detailed
information.
The report provides information and discussions on cooling system
configurations, operation, environmental effects, and costs.
Consideration is given to the intake as well as the discharge.
Various closed-cycle cooling systems employing cooling towers, cooling
ponds, spray systems, and other devices are covered. Methods of
assessing alternative selections and benefit-cost analyses are
presented. Non-thermal aspects of cooling water systems are discussed.
The report lays the groundwork for a technically sound EIS review;
however, the reviewer must supplement the material presented herein
with references and perhaps technical consultation to prepare
comprehensive and detailed review comments.
ii
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CONTENTS
TITLE PAGE
Abstract ii
List of Figures iv
List of Tables v
Acknowledgements vi
Sections
I Summary 1
II Introduction 2
III General Plant Assessment 7
IV Cooling Systems 11
A. Introduction 11
B. Intakes 14
C. Closed-cycle Cooling 21
D. Once-through Cooling 54
E. Combination Cooling Systems 62
V Chemical, Biocidal, and Sanitary Wastes 67
VI Alternative Cooling Systems 73
VII Benefit-cost Analysis 76
VIII References 88
111
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FIGURES
No. Page
1 Flow Chart for Evaluating Thermal
Power Plant Cooling Systems 4
2 Cooling Water Requirements for
Fossil and Nuclear Power Plants 13
3 Intake Designs 17
4 Intake Designs 18
5 Intake Designs 19
6 Geographical Distribution of
Potential Adverse Effects from
Cooling Towers 31
7 Cooling Pond Size vs. AT 37
8 Pond Area vs. Inlet Temperature 38
9 Mixed vs. Flow-through Ponds 40
10 Pond Evaporation vs. Wind Speed 43
11 Pond Evaporation vs. Inlet Temperature 45
12 Seasonal Performance of an Auxiliary Cooling Pond
for a 1,500 MWe Fossil Fueled Power Plant 64
IV
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TABLES
No. Page
1 Recirculating Water Quality Limitations 26
2 K and E Values 36
3 Comparison of Mechanical Draft Tower Cooling Limits
to Receiving Water Temperature 65
4 Residual Chlorine Recommendations 69
5 Capital Costs for Nuclear Plant Cooling Systems 79
6 Busbar Cost Increases—Cooling Systems for Power
Plants Near Lake Michigan 81
7 Relative Busbar Costs (Mills/KWH) for Nuclear Power
Plant Cooling Systems 82
8 Costs of Capability Loss and Added Fuel Attributed
to Various Cooling Systems 84
9 References for Detailed Economic Review 85
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ACKNOWLEDGEMENTS
The principal individuals contributing individually and collectively
to the substance of this report are, in alphabetical order: Alden G.
Christiansen, Frank H. Rainwater, Mostafa A. Shirazi, and Bruce A.
Tichenor.
VI
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SECTION I
SUMMARY
This report provides the Environmental Impact Statement (EIS) reviewer
with background information to assist in the development of technically
sound review comments. The techniques and data presented herein must
be supplemented by the references cited to give the review process a
substantial technical base. This report is limited to discussions
of the engineering aspects of power plant cooling system, and does not
deal with the biological portions of EIS's.
In most cases, the material presented will enable the reviewer to make
an initial and reasoned judgment as to the adequacy of the EIS. For
example, "Are the data presented on cooling tower water loss accurate?",
"Is the cooling pond size reasonable?", or "Are the costs excessive?"
It must be recognized, however, that a complete technical analysis of
a specific problem, such as for an adversary proceeding, will require
the use of techniques beyond the scope of this report. These techniques
are presented in the references. In addition, some problems preclude
an easy solution (e.g., thermal plume analysis). Here again, the reviewer
will have to rely heavily on the reference material. Consultation with
specialists may also be required.
While this report provides substantial information relative to the review
of thermal power plant cooling systems, in the end the responsibility
for the technical adequacy of the review rests with the reviewer. He
must use all of the technical and intellectual resources available to
him. Individual initiative coupled with common sense must be applied
to the review process, and no report or reference can supply these
requirements. Thus, the review process requires substantial effort;
it is hoped that this report will provide a solid basis for that effort.
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SECTION II
INTRODUCTION
PURPOSE
Section 102 of the National Environmental Policy Act of 1969 (NEPA)
requires Federal Agencies to evaluate the environmental impact of
their actions, including licensing. The Calvert Cliffs decision
(U. S. Court of Appeals, District of Columbia, Nos. 24839 and 24871)
highlights the applicability of NEPA to the licensing of nuclear power
plants and leaves no doubt as to the need for technically sound and
comprehensive environmental impact statements (EIS's) as a basis for
licensing.
The Atomic Energy Commission has issued guidelines for applicant's
reports used in preparation of environmental impact statements, which
have proliferated in response to current requirements. Throug'h May
31, 1973, the National Thermal Pollution Research Program has provided
technical input to EPA's review comments on about 80 draft environmental
impact statements for nuclear power plants, covering a wide range
of siting, engineering, and ecological combinations. Review of nuclear
power plant EIS's will be a continuing function of regulatory agencies;
fossil fueled plants will also require EIS's in some cases and detailed
review in others. From the standpoint of technical analysis of cooling
systems, fossil fired plants do not differ from nuclear plants, and
most of the technical material in this report are applicable to both
types of thermal power plants.
The purpose of this report is to (1) identify the environmentally
critical facets of cooling water systems, (2) point out some of the
problems that frequently surface in impact statement reviews, and
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(3) summarize and reference the many research products applicable to the
engineering-economic-environmental analysis required of EPA. Water
quality criteria are not included.
Figure 1 provides a "flow chart" of the review process for thermal
power plant cooling systems. More specifically, Figure 1 highlights
particular points of concern which will require technical consideration
by the reviewer.
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Figure 1. Flow Chart for Evaluating Thermal Power Plant Cooling Systems
Intake
Chemical,
Biocidal,
and Sanitary
Wastes
Closed-Cycle
I Placement
Screens
Once-through
Cooling
Device
ical
bility
Economics
Combination
Condenser
Cleaning
Types
of
Chemicals
Quantities
Discharged
Benef 1 ts
Costs
Methodology
Cooling
Device
Operating
Rules
Operating
Characteristics
Water
Consumption
Environmental
Effects
Discharge
Configuration
Plume
Temperature
Prediction
Water
Consumption
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CRITICAL ENVIRONMENTAL ASPECTS OF COOLING WATER SYSTEMS
Cooling systems can impact the environment several ways. The word
"system" is chosen advisedly. Most components are interrelated and
hence can and should be considered together for environmental optimization,
It is significant to note that of the many plants reviewed to date,
only one is so poorly sited that design of an environmentally acceptable
cooling systems is virtually impossible.
The EIS review should consider as a minimum the following:
1. Rate of cooling water withdrawal, with respect to:
a. Local and regional water supply and uses and the effect
of proposed withdrawals thereon.
b. Entrainment and subsequent kill of planktonic organisms
in passing through the condenser.
2. Intake design and hydraulics with respect to entrapment and
damage to fish.
3. Temperature rise across the condenser.
4. Effluent mixing zone.
a. A maximum temperature of discharge increase in temperature
above natural.
b. Size and geometry.
5. Land requirements for cooling systems, particularly ponds.
6. Water loss.
7. Local meteorological effects such as fog or ice.
8. Drift characteristics and terrestrial impact.
9. Chemical or physical cooling water treatment program.
10. Slowdown.
a. Cycles (multiples) of concentration and flowrate
b. Treatment and/or disposal
11. Overall minimization of waste discharges to water, air,
and land.
12. Cost implications of environmentally desirable refinements or
alternatives.
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GENERIC DEFICIENCIES OF ENVIRONMENTAL IMPACT STATEMENTS
Although the technical quality of draft statements differs widely,
the major, or more frequently occurring, deficiencies are in five
areas:
1. The staff preparing the statement ignores or does not describe
proximal and cumulative waste sources, and presents the plant as dis-
charging into virgin waters. An "area of influence" approach to
environmental assessment is required.
2. Inadequate data or description of methodology are presented
in the draft or supplemental Environmental Reports for EPA's independent
review and evaluation. EPA cannot accept unsupported statements such
as "applicable water quality standards will be met" or "the 3°F isotherm
will encompass only 35 acres."
3. 'Alternative cooling systems are treated in a cursory manner.
Such treatment is justified only if the proposed system is obviously
the best choice to protect the environment. Otherwise a thorough and
accurate analysis of secondary environmental impacts and costs is
required.
4. Data or conclusions presented on cooling system performance
and secondary environmental impacts are obsolete or grossly inaccurate.
5. Economic (benefit-cost) analysis of alternative systems is
inadequate or inapplicable to system selection.
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SECTION III
GENERAL PLANT ASSESSMENT
No two sites or plants are identical. Seldom, if ever, is a power
plant located or designed with environmental protection as the primary
objective function. This is not to say that some progressive utilities
do not do everything reasonable to negate or minimize adverse impacts.
It follows that such differences between plants affect the feasibility
of various cooling alternatives, the choice among alternatives for
maximum environmental protection, and the monetary costs.
As a first step in the review process, it is advisable for the reviewer
to become familiar with the plant as a whole as described in the
EIS and in backup material such as the utility's environmental report.
Information pertinent to the cooling system evaluation is often found
scattered throughout various EIS sections. All applicable information
should be located.
The initial perusal should also be used to catalog general information
affecting the acceptability of the cooling system choice. This includes
such factors as hydro!ogic and meteorologic conditions, general water
and land availability and use, recreation, etc.
In the general assessment, the reviewer considers the size of the
generating unit or units covered in the statement and any additional
units existing or planned at the site. He must also consider the plant's
thermal output, the cooling water requirements, and the temperature
rise across the condenser. The interfaces of the plant characteristics
with cooling systems are described in two EPA contract reports prepared
2 3
by Dynatech R/D Company and Hittman Associates, Inc.
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Location characteristics such as hydrology, meteorology, topography,
land area, and rural versus urban setting should also be considered
because they can influence the cooling system choice. A few generalizations
(which may not hold for any particular site) exemplify such relations:
]. If intake water is scarce or water appropriation is an issue,
the cooling system should be designed to minimize water intake and
consumption. Normally, once-through cooling is out and cooling towers
or spray systems would be preferable over cooling pond construction
because of the differential in water loss.
2. Meteorology controls the efficiency and limits of all cooling
systems and influences their potential adverse environmental effects.
3. There are several regional generalizations related to geography
or topography. Along much of the West Coast and some of New England,
deep, cold ocean receiving water can be reached by a discharge pipe in a
short distance and at reasonable cost. In such cases, the rapid mixing
attributes of submerged diffusers on a once-through system might be
exploited. Conversely, most of the coastal waters of the Gulf of Mexico
and the southeastern United States are too shallow for submerged diffusers
to be either effective or economical. In the Applachian Highlands natural
draft towers are usually selected over mechanical draft towers to get
the exhaust plume up over the ridges and minimize contribution to
characteristic valley fog. Conversely, in the hurricane or tornado
prone Atlantic Seaboard or Midwestern Plains, the comparative structural
stability of mechanical and natural draft towers can favor the former.
In the Colorado River Basin and other parts of the arid west, the probability
of fogging problems is remote, but water availability and salinity are
prime water quality problems; in this case, cooling system selection and
operation should be developed to minimize consumptive use of water and
salinity contribution. In fact, dry or wet/dry towers on mine mouth
plants are not beyond the pale of economic feasibility in the region.
4. The significance of land availability and urban versus rural
setting are rather obvious. Usually the exclusion zone and other site
limitations for nuclear power plants provide ample space for closed-cycle
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cooling systems, but attention must be given to items such as tower
height, proximity to airports, and the probability for fogging of major
highways.
5. Added benefits may accrue to cooling ponds from recreational
use. On the other hand, such large areas are required for nuclear power
plants that close attention must be given to other land use penal ities
and to the efficiency of the pond design (see Section IV); the least
-cost design—measured in terms of construction—can be wasteful both
in terms of land and water resources. Ponds are somewhat unique among
cooling systems in that electric utilities may in some locations acquire
under condemnation proceedings land that will actually appreciate in
value over the life of the plant.
In addition to plant and site characteristics, the stage of design or
construction is an important factor. A plant ready to go on line or for
which most components are installed cannot be sent back to the drawing
board. The draft review must be directed to the question, "What is
reasonable for this plant at this time?"
The reviewer will usually find that much more information is given
relative to the cooling system selected by the utility than to alternative
possibilities. This is more acceptable in some cases than others. For
example, when commitments and funding for design, equipment, or construction
have already been made, the cost-benefit ratio has been biased in favor of
the chosen system; it is then very difficult to justify a complete
system change unless environmental effects are totally unacceptable. In
this case, it is most important to place primary review emphasis on the
design and operation of the chosen system to ensure that the utmost
environmental compatibility is achieved under the circumstances.
In cases where significant commitments and funding have not been made
toward a specific design, a more unbiased situation exists and the
reviewer should evaluate all possible alternatives in a thorough and like
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manner. This will require more back-up information on all systems so
that a truly optimum system may be obtained.
After initial familiarization with all available information and general
assessment of broad considerations described in this Section, the reviewer
can proceed with the more detailed evaluation of the proposed cooling
system and its alternatives.
10
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SECTION IV
COOLING SYSTEMS
A. INTRODUCTION
Thermal power plant cooling systems contain three basic elements:
1. An intake for supplying cooling water to the power plant.
2. A condenser where the turbine exhaust steam is condensed at
low temperature and pressure while transferring the waste heat to the
cooling water.
3. A device or mechanism for transferring this waste heat to
the atmosphere (and finally to the ultimate sink—outer space).
These three elements should be designed to "match" the steam turbine
in an optimum manner to minimize the cost of producing electric power
4
and, at the same time, prevent adverse environmental effects . In
evaluating the environmental effects of a power plant cooling system,
most of the attention is focussed on the third element—the mechanism
used tp transfer the waste heat from the cooling water to the atmosphere.
In practice, there are three basic methods of dissipating the waste heat
to the atmosphere:
1. Closed-cycle cooling—this method requires an off-stream
cooling device (i.e., pond, tower, spray system) to transfer the
waste heat to the atmosphere. The cooling water is recycled through
the cooling device after each pass through the condenser, and only a
small portion of the cooling water (blowdown) is discharged to an
adjacent water body or to an additional treatment facility.
2. Once-through cooling—in this method the cooling water is
pumped from an adjacent water body (i.e., river, lake, reservoir,
11
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ocean, etc.) through the condenser and discharged back to the water
body. The waste heat is transferred to the atmosphere from the heated
receiving water.
3. Combination cooling—this mode utilizes an off-stream cooling
device to dissipate a portion of the waste heat load. The cooling
water flow from this device may be sent directly to the receiving water
or it may be recycled back to the condenser.
For any given power plant, the method of dissipating the waste heat
dictates the amount of water flow through the intake. For once-through
systems, a continuous flow of a thousand or more cfs is required for
large nuclear power plants (see Figure 2) . For closed-cycle systems,
intake requirements are substantially less. Other water requirements
(e.g. - service water, boiler make-up, etc.) are low in volume and can
generally be disregarded in an evaluation of the waste heat disposal problem.
12
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FIGURE 2
COOLING WATER REQUIREMENTS FOR
FOSSIL AND NUCLEAR POWER PLANTS
NUCLEARt
T)f = 33 %,
IN-PLANT LOSSES
= 5%
FOSSIL,
71 • 40%
IN-PLANT AND
STACK LOSSES
= 15%
2500
0 (000 2000 3000
COOLING WATER FLOW (Q), cfs
AT - CONDENSER TEMP. RISE
THERMAL EFFICIENCY
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B. INTAKES
Cooling water intake structures for thermal power plants encompass a
wide variety of designs. In general, however, intakes usually consist
of:
1. A log boom to prevent large floating material from entering
the intake area.
2. A trash rack to hold back medium size (approximately 4")
debris.
3. A wire mesh screen to prevent the passage of small debris and
fish through the condenser.
Variations of these standard components include the lack of log booms on
submerged offshore intakes and the use of skimmer walls on canal type
intakes.
The problems associated with the intake of large volumes of cooling
water include:
1. The entrainment of organisms and subsequent passage through the
power plant cooling system where, depending on design, time and temperature
of exposure, and species of organisms, a variable fraction are killed.
2. The impingement of fish on intake screens.
3. The entrapment of fish in the intake structure (i.e., screenwell).
Intakes can and should be designed to reduce these effects.
The major environmental design problem is the prevention of fish kills
at the intake. Naturally, the best technique is to minimize the number
14
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of fish which enter the intake area. This can be accomplished by
locating the intake in an area of low fish population, reducing the
velocity of the intake water, and eliminating areas where fish can be
trapped (e.g., screenwells with no fish by-pass). If fish do go as
far as the screens, provisions for fish by-pass or collection and
harmless removal should be,provided.
It should be noted that wire screens are used to "protect" the power
plant, not the fish.. Vertical travelling screens (the most common type)
are usually moved only after a specified pressure drop across the screen
face is reached. Thus, a fish may be impinged on the screen for several
hours before removal, and thus suffer damage and possible death. In
many cases, whether the fish is alive or not does not matter, since the
material on the screen is often disposed of in a manner which causes
mortality. Therefore, fish, should be by-passed or collected prior to
impingement on such screens. If continuously moving screens are employed,
a suitable fish removal technique might be developed.
Several general criteria can be suggested for proper intake design and
placement:
1. Place the intake to avoid recirculation of the discharged
cooling water. Recirculation will cause increased thermal stress to
entrained organisms as well as reduce,the plant's thermal efficiency.
If intake and discharge points must be separated by considerable distance
to prevent recirculation, overall biological damage is reduced if the
intake is the long leg and the discharge is the short leg of the cooling
water system.
2. Avoid placing the intake in an area of high biological value
(e.g., spawning, rearing, migration areas).
15
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3. Reduce intake velocities to below 0.5 ft/sec at the trash
rack to enable fish to escape the screenwell. Note that the use of fish
avoidance techniques such as electrical fish "screens," air bubble
"curtains," light, and sound have proven generally ineffective under
field conditions (e.g., air bubbles and electric screens at Indian
Point ). Thus, low velocity is the only effective method, at present,
to prevent fish from entering the intake.
4. For off-shore, submerged intakes, velocity caps should be
used to reduce fish entrainment. Note, however, that the effectiveness
of such devices is not universally accepted .
5. For shoreline intakes, avoid breaks in the natural shoreline
and avoid the use of intake canals, since both may act as "fish traps."
6. Fish by-pass or collection and removal facilities should be
provided in the screenwell. Stationary louvers have proved effective
in guiding fish and could be employed as a fish by^-pass system.
7. Travelling screens (mesh size of 3/8" or less) should be
employed. Continuous movement with suitable fish removal procedures
is preferred over intermittent movement. Note that horizontal traveling
screens, now under experimental investigation, may prove effective as
fish by-pass devices.
As an aid in assessing the adequacy of a given intake design, the reader
is referred to Figures 3 through 5 taken from a report prepared by the
State of Washington Water Research Center under an EPA grant . These
figures indicate both good and bad intake design configurations.
All other factors being equal, biological damage due to condenser passage
is directly proportional to the volume of make-up water withdrawn. Thus
closed-cycle systems will cause less damage of this type than once-through
systems. The following portion of this Section includes discussion of
intake flow rates for closed-cycle cooling systems.
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rf
1
y
a
I
_SC_REEI
f
V
TRASH
\^
RIVER FLOW
OR
STILLWATER
RECESSED SCREEN
NO BY-PASS
POOR DESIGN
RIVER FLOW
OR
STILLWATER
SMOOTH FACED SCREEN
NO BY-PASS
SOMEWHAT BETTER DESIGN
FIGURE 3
INTAKE DESIGNS
17
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PIPE RISER
TO UNDERGROUND
RETURN PIPE
RIVER FLOW
SURFACE SLOPE
SMOOTH-FACED SCREEN
WITH BY-PASS
BETTER DESIGN
ICE BARRIER * I I I I.. . .TTT
TRASH RACK ^
FLOW
SMOOTH-FACED SCREEN
RIVER BECOMES BY'PASS
BEST DESIGN
FIGURE 4
INTAKE DESIGNS 7
18
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PIPE RISER
TO UNDERGROUND
RETURN PIPE—*
RIVER FLOW
OR STILLWATER
ANGLE FACE
WITH BY-PASS
GOOD DESIGN
a.
UJ
S.
'\
c
k
\\~
Nv^j
•VM
\
TRASH RACK
RIVER FLOW
OR STILLWATER
REVERSE ANGLE FACE
USING ONE BY-PASS
BEST DESIGN
FIGURE 5
INTAKE DESIGNS
19
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Intake icing should also be considered. Severe icing could cause flow
restrictions and/or structural damage, so de-icing procedures are
sometimes employed. Such procedures generally include the discharge
of warm condenser effluent in the vicinity of the intake (i.e., pur-
poseful recirculation). If such warm discharges act as fish attractants,
increased entrainment problems could occur. In addition, rapid "shut
off" of this heated discharge at the conclusion of the de-icing program
could cause cold shock to nearby organisms. Thus, the EIS reviewer
should carefully evaluate proposed de-icing plans.
For further information on intake design considerations, the reviewer
should consult the reports by Hanford Engineering Development Laboratory ,
7 R *
State of Washington Water Research Center , and Johns Hopkins .
20
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C. CLOSED-CYCLE COOLING
Several types Of cooling devices are available for use in a closed-cycle
cooling system, including:
1. Wet cooling towers (mechanical or natural draft).
2. Cooling ponds (flow-through or completely mixed).
3. Spray cooling systems (canal or pond type).
4. Dry cooling systems (direct or indirect; mechanical or natural
draft).
5. Wet/dry cooling towers (mechanical or natural draft).
In reviewing an EIS for a plant using closed-cycle cooling, three basic
factors should be considered:
1. Operating characteristics
2. Water consumption
3. Environmental effects.
Following is a discussion of these factors relating to the above cooling
devices.
Wet Cooling Towers
Operating Characteristics -
Wet cooling towers, both mechanical and natural draft, dissipate the
majority (approximately 75 percent) of the waste heat in the cooling
21
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water by latent heat transfer (evaporation) with the remainder lost by
sensible heat transfer (conduction-convection). The wet-bulb temperature
of the ambient air is the minimum temperature to which the water can be
cooled. The tower is designed to cool the water to some specified
temperature above the wet-bulb temperature.
The approach of the tower is defined as the difference between the cool
outlet water and the wet-bulb temperature. Approaches of 15-20°F are
generally used. The cooling range is the difference between the hot inlet
water temperature and the cool outlet water temperature. In a closed-cycle
system the range equals the condenser temperature rise and is generally
between 25 and 40°F. Thus, given information on the approach, range, and
wet-bulb temperature, one can determine the inlet (hot leg) and outlet
(cold leg) tower temperatures.
In evaluating these temperatures, one must differentiate between design
conditions and average conditions. Design wet-bulb temperature is often
designated as not to be exceeded more than a fixed percentage (say 5%) of
the time during the summer months. It represents a severe condition.
Average conditions will be much more moderate. For example, a particular
tower may be designed for a 15°F approach, a 30°F range, and 75°F wet-bulb
temperature. This would provide a 120°F tower inlet temperature with
a 90°F outlet temperature. Under more moderate off-design conditions,
much cooler temperatures will be realized.
In reviewing an EIS, substantial operating and design data with respect
to heat dissipation are not required. It is generally sufficient to
assume that the particular tower design selected will be adequate to
dissipate the waste heat load. However, information on the water balance
of the tower is critical to the review process.
For more details on cooling tower operation and design, the reviewer
is referred to Marley , McKelvey & Brooke , and Dynatech^.
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Water Consumption -
Since wet cooling towers operate primarily by latent heat transfer,
significant quantities of water are consumed by evaporation. Two rough
methods estimating the water loss by evaporation are available.
1. Assume that 75 percent of the waste heat is dissipated by
latent heat transfer. Thus, using a value of 1,000 Btu/lb for the
latent heat of vaporization for water, one can easily calculate the
approximate evaporative loss on the basis of total waste heat to the
cooling water. For example, a 1,000 MWe nuclear power plant with
a thermal efficiency of 33 percent and 5 percent in-plant losses discharges
g
6.4x10 Btu/hr to the cooling water. Thus, one can compute the tower
evaporation loss as:
(6.4xl09 Btu/hr) (75%)/(1000 Btu/lb) = 4.8xl06 Ib/hr or 21.4 cfs.
(Conversion factor: 1 cfs = 0.225xl06 Ib/hr)
i
2. One can also compute the evaporation loss given data on
cooling water flow rate and condenser temperature rise. Using the
same assumptions as above, the evaporation loss is equal to 0.75 percent
of the flow rate per 10°F drop (or rise) in cooling water temperature.
Thus, for the example shown above (temperature rise equals 30°F, flow
rate equals 950 cfs, see Figure 2) the evaporation loss equals:
(0.75%) (950 cfs) (30/10) = 21.4 cfs.
Both of these calculations were conducted assuming the plant was operating
under full load. To compute the average annual evaporation loss, one
should multiply this value by the annual plant load factor. For example,
given the same data as above with an annual load factor of 82 percent,
the average annual evaporation loss would be:
(21.4 cfs) (82%) = 17.5 cfs
23
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Finally, to compute the maximum (or design) evaporation rate under high
dry-bulb temperature conditions which will minimize convective heat loss,
one should assume that 95 percent of the waste heat in the cooling water
is lost by evaporation. Thus, the maximum evaporation rate for the
above example would be:
(21.4 cfs) (95/75) = 27.1 cfs
Note that the methodology presented above is only approximate, but it
should enable the reviewer to evaluate the EIS data on evaporation in
a reasonable manner. A more detailed technique is presented by Hittman
3
Associates, Inc.
Another mechanism by which water is lost from a wet cooling tower is
drift. As the water falls down through the tower packing and below,
it is possible for small droplets to become entrained in the air stream
moving out through the tower top. These droplets have the same chemical
characteristics as the cooling water in the system. The use of drift
eliminators above the packing can reduce the drift loss substantially.
State-of-the-art design can be used to obtain drift losses of 0.005%
of the circulating flow rate for mechanical draft units and 0,002% for
12
natural draft towers . In no case should the drift loss exceed 0.01%
for modern, well-designed towers. The only exception would be for a
tower designed to maximize the drift loss in order to reduce the blowdown
volume (see below).
The process of evaporation in a wet cooling tower causes an increase
in the concentration of dissolved and suspended material in the circulating
water. In order to prevent a build-up of undesirably high concentrations
in the system, a small portion is continually or intermittently bled
from the system. This stream is called blowdown. The blowdown (B) is
a function of the available make-up (B+D+Ev) water quality and is related
24
-------
to evaporation (Ev) and drift (D) in the following manner:
C = (B + Ev + D)/(B + D) (1)
In this equation, C equals cycles of concentration, a dimensionless number
which expresses the number of times the concentration of any constituent
is multiplied from its original value in the make-up water. (It does
not represent the number of passes through the system). B, Ev, and D
are expressed in consistent units (e.g. percent of circulating water
flow rate or actual flow rate).
For average make-up water quality, conventional practice sets the value
of C between 4 and 6. For extremely high makeup quality water (or treated
water) C values of 15 and above are possible. For salt or saline water,
C values as low as 1.2 to 1.5 may be required. This is usually not a
materials or operating limit, but rather a means of preventing biological
damage from blowdown salinity.
The chemical characteristics of the recirculating water (treated or
untreated) determine the maximum C value. Table 1 provides some "rules
of thumb" to be used in establishing the maximum C value. Note that
the C . . . designations used in the table represent individual
constituent concentrations and should not be confused with C, cycles
of concentration used above.
25
-------
Table 1
RECIRCULATING WATER QUALITY LIMITATIONS
Characteristic
Limitation
Comment
pH and Hardness
Langelier Saturation
Index = 1.0
Langelier Saturation
Index = pH-pHs
where
pH and Hardness
with addition of
proprietory chemicals
for deposit control.
Langelier Saturation
Index = 2.5
pH = measured pH
pHs = pH at saturation
with CaC03
See Sisson13 for
nomograph solution.
Sulfate and Calcium
Silica
Magnesium and Silica
(CSQ ) x (CCa) = 500,000
CSi0
« 35,000
= concentration of
S04 in mg/1
= concentration of
Ca in mg/1 as CaC03
CSiO = concentration of
M
Si Op in mg/1
= concentration of
Mg in mg/1 as CaCO,
26
-------
The "Limitation" column in Table 1 indicates the maximum value allowed in
the recirculating water for each chemical characteristic given. The
maximum C value would be established when any one of the "Limitations"
is exceeded. Note that this table provides "rule of thumb" estimates,
which may not be applicable to unique water quality problems.
The equation for C can be rewritten for blowdown (B):
p _ Ey-D(C-l) {2]
C - 1 u'
In order to minimize the total amount of make-up water by the cooling
tower, one should operate at as high a C value as possible. The following
data were computed using the above equation and illustrate the effect
of C on the blowdown and make-up flow rates:
C Blowdown Make-up
(cycles of concentration) (cfs) (cfs)
1.2 107 128
1,5 42.8 64.2
2. 21.4 42.8
5. 5.3 26.7
10. 2.3 23.7
20. 1.1 22.5
This table was developed assuming an evaporation rate (Ev) of 21.4 cfs
and a drift rate (D) of 0.05 cfs (0.005% of 950 cfs).
There are several advantages to maintaining a high C value:
a. Minimizing the make-up water requirement, thus reducing the
number of organisms entrained in the cooling water.
b. Minimizing the volume of blowdown water to be discharged.
27
-------
c. Reducing the size and cost of make-up and blowdown handling
facilities (i.e., pumps, pipes, screens, etc.).
Environmental Effects -
In addition to the consumption of water, wet cooling towers can cause
potential adverse side effects due to the vapor plume, drift, and blowdown.
Cooling tower plumes have the potential for causing or increasing
local fogging or icing conditions. The key word here is potential,
since in most cases, no such problems will occur. Fog is defined
here as a condition where vision is obstructed.
Cooling towers do produce visible plumes; however, plumes are normally
not a problem unless they reach the ground. Under normal conditions,
cooling tower plumes rise due to their initial velocity and buoyancy and
rarely intersect the ground before they are mixed with the ambient air
and dissipated. However, under adverse climatic conditions (i.e.,
high humidity and low temperature), the moisture could produce a fog
condition if it were trapped in the lower levels of the atmosphere,
such as during a period of high atmospheric stability (i.e., an inversion).
In almost all cases, natural draft towers are less likely to cause fogging
problems than mechanical draft towers. Mechanical draft towers may
cause problems, but in most cases fogging and icing would be on-site
(i.e., within 1000-2000 ft of the tower). Also the limited vertical
mixing occurring during neutral stability conditions could limit plume
dispersion.
Several analytical techniques have been used to evaluate the fog potential
of cooling tower plumes:
1. One method is to estimate the concentration of liquid water
added by the cooling tower plume to the ambient atmosphere in the vicinity
of the cooling tower. EG&G indicates that the amount of liquid water
added by cooling towers is normally between 0.1 and 0.5 grams per cubic
28
-------
meter, one or more kilometers downwind from cooling towers. Thus, any
time the difference between the liquid water content of saturated air
and the liquid water content of the ambient air is less than 0.1 to 0.5
grams per cubic meter, there is a potential for fog conditions within
the specified distance from the cooling tower. Thus, a method which
can be used to determine whether or not fog may occur for a particular
tower is to evaluate the percent of time that the ambient air contains
a liquid water concentration sufficiently close to the saturation liquid
water content (i.e., within 0.1 to 0.5 grams per cubic meter). This
method was used in analysis of potential fog from cooling towers in the
vicinity of Lake Michigan and is described in detail in a 1970 FWQA
4
report .
2. Another method involves approximating the dilution of a
cooling tower plume by the ambient atmosphere using standard methods of
evaluating smoke plumes from a point source. In this method one computes
the total amount of liquid water added by the cooling tower and determines
the downwind mixing with the ambient atmosphere by using the classical
Gaussian dispersion models available in standard textbooks on air
pollution . This method was also used in evaluating potential fog
4
from cooling towers in the vicinity of Lake Michigan .
3. Also available are mathematical models of cooling tower plumes
which take into account the rise of the plume using information on cloud
physics, such as liquid-vapor phase change reactions, liquid water content,
and precipitation. To date, such models lack complete verification with
field data and are thus subject to engineering judgment in their use.
References on such models include EG&G , Hanna ' and Sierra Research ,
4. Finally, empirical methods are also used in the prediction
of potential fog from wet cooling towers. These methods utilize
field observations from existing towers and correlation with meteor-
olgical information. TVA has developed such models using data from their
in
Paradise plant .
29
-------
In reviewing that portion of the EIS describing the fogging potential
of a cooling tower, one should assess the duration (e.g., hours per
year or percent of time), frequency (number of occurances per year), and
location (e.g., highway, airport, residential or industrial area) of
the predicted episodes. A careful check of the methodology coupled
with a critical evaluation of the meteorological data is required. In
addition, the description of the methodology used for prediction should
be sufficiently detailed to allow the reviewer ,to prepare independent
calculations. In many cases, only a cursory analysis is provided, which
may be sufficient if the site is not subjected to prolonged periods of
high humidity and low temperature. A final point to consider is a
possible interaction between the cooling tower plume and nearby point
sources of air pollution from industrial plants. Potential problems such
as acid mist may occur due to such interactions and would require further
analysis.
''*'-" .," •
As a rough check on the fog potential of power plant cooling towers,
14
Figure 6 may be used. According to EG&G , this map provides a
"qualitative classification for the potential for adverse cooling
14
tower effects." The following criteria were used by EG&G in developing
this map.
a. High Potential.
Regions where naturally occuring heavy fog is observed over 45 days
per year, where October through March the maximum mixing depths are
low (400-600 meters), and the frequency of low-level inversions is
at least 20-30 percent.
b. Moderate Potential.
Regions where naturally occuring heavy fog is observed over 20 days
per year, where October through March the maximum mixing depths are
less than 600 meters, and the frequency of low-level inversions is
at least 20-30 percent.
30
-------
FIGURE 6
GEOGRAPHICAL DISTRIBUTION OF
POTENTIAL ADVERSE EFFECTS FROM
COOLING TOWERS
HIGH POTENTIAL
SS353 MODERATE POTENTIAL
SLIGHT POTENTIAL
31
-------
c. Low Potential.
Regions where naturally occuring heavy fog is observed less than
20 days per year, and where October through March the maximum mixing
depths are moderate to high (generally greater than 600 meters).
It must be emphasized that the classifications of "high," "moderate,"
"low" potential are relative rather than absolute descriptors. Thus,
a cooling tower located in an area of "high potential" would be more
likely to cause a fogging problem than one located in an area of
"moderate" or "low potential," but whether or not the tower ever
produced a fog problem would depend upon specific site and climatic
conditions.
During sub-freezing weather, fogging and drift conditions may result
in icing. As with fog, experience with large power plant cooling towers
has not resulted in major icing problems. Methods of predicting the
accumulation of ice due to cooling tower plumes are not widely reported.
In general, icing caused by plumes will be a low-density accumulation
of granular ice tufts and is unlikely to cause damage due to its weight.
A problem to be considered would be associated with the danger of icy
roads. It should be noted that icing caused by the plume will be
generally limited to vertical surfaces, and icing of horizontal roadways
will be less severe. When such conditions may occur, the EIS should contain
data on icing frequency, duration, and location. Also, suggestions
for preventing safety problems should be made (i.e., plans for caution
signs and/or lights).
As discussed above, drift is entrained water that is carried out of
the top of a wet cooling tower in liquid droplets rather than as vapor.
While some objection has been raised concerning the environmental
effects from freshwater cooling towers, more vocal opposition has been
expressed to large salt water towers because of the potential damage
to the surrounding area from fallout of salt discharged to the
atmosphere in drift particles.
32
-------
In addition to data on the amount of drift given previously, some
information is also available on the size of drift particles. Environmental
12
Systems Corporation conducted measurements on a mechanical draft tower
(drift rate 0.005%) which showed that the size of particles contributing
the majority of the total mass ranged from about 100 to more than 300
microns in diameter. Particles less than 100 microns in diameter
contributed only about 5 percent of the total drift mass. On the other
hand, measurements taken a few feet above the eliminators in a natural draft
tower showed few particles greater than 100 microns.
In order to evaluate the environmental effect of drift, one must be
able to predict the amount of deposition on the surrounding landscape.
Unfortunately, the state-of-the-art is inadequate to precisely quantify
the fallout characteristics of cooling tower drift; however, qualitative
20 . 21
deductions are possible. Papers by Stewart and Hosier, et. al. can
be used to provide such qualitative deductions. In general, these papers
indicate that the majority of the drift particles will fall out within
2,000 feet of a cooling tower under normal conditions.
Two basic problems prevent one from making a firm judgment on the
severity of environmental problems associated with cooling tower drift
from salt water towers. First of all, only limited and qualitative
information is available on the effect of various levels of salt
concentration on various species of vegetation. Second, in order to
effectively evaluate the cooling tower drift effect, information
on the salt concentration in the ambient atmosphere and its deposition
must be obtained. Such data are generally unavailable.
While limited experience has been gained in the operation of salt
water cooling towers, no adverse environmental effects have been
experienced at a tower which has been operating in Fleetwood, England,
for several years. In addition, cooling towers associated with oil
refineries in Texas and New Jersey have been operated on salt water
for some time without objectionable effects. However, these examples
33
-------
should not be cited as proof, at the present time, that salt water
towers can be used at any given site without drift damage to any_
type of surrounding. Finally, large natural draft cooling towers
have been planned for operation on salt water at the Chalk Point power
plant in Maryland and the Forked River nuclear power plant in New Jersey.
Two excellent references which discuss the problem of drift from salt
22
water cooling towers are a report by Westinghouse and the Forked
River EIS23.
The environmental effects of bl owdown and its treatment and disposal
are discussed later in Section V of this report.
Cooling Ponds
Operating Characteristics -
Cooling ponds are simply open bodies of water which use the natural
heat exchange processes of evaporation, radiation, and conduction-
convection to dissipate a power plant's waste heat load. The design
of a cooling pond depends upon the plant size, the local meteorology,
and the pond type— mixed or flow-through. Mixed ponds have uniform
surface temperatures; flow-through (or slug flow) ponds are designed to
exhibit a temperature decay from the warm inlet to the cool outlet.
Flow-through ponds require smaller surface areas than mixed ponds.
The determination of cooling pond area requires an analysis of the
pond's energy budget. An approximate analysis of the energy budget
can be used by the EIS reviewer to calculate pond size. This method
is referred to as the equilibrium temperature technique and involves
a one-dimensional exponential temperature decay equation. Assuming a
flow-through pond, the pond performance is described by:
Tout = (Tin " E) exp (-0-505KA/pC Q) + E (3)
34
-------
Where Tout = pond outlet temperature, °F
Tjn = pond inlet temperature, °F
E = equilibrium temperature, °F
K = energy exchange coefficient, Btu/day ft2 °F
Q = cooling water flow, cfs
3
p = water density, Ib/ft
C = specific heat, Btu/lb°F
A = pond surface area, acres
K and E values are basically functions of meteorological conditions.
24
Methods of computing these parameters are found in Edinger and Geyer
or nr
and in the Industrial Waste Guide on Thermal Pollution . Brady, et. al.
provide approximate techniques for computing K and E values. Also,
values of K and E for average and extreme meteorological conditions are
27
contained in a report by Vanderbilt for various locations throughout
the United States. K and E values should be averaged over the time
of passage through the pond, which is usually at least a week.
The above equation can be simplified in order to provide direct computation
of pond area. Given a water density (p) of 62.4 Ib/ft and specific
heat (C ) of 1 Btu/lb°F and solving for A gives:
A = (123Q/K)ln [(T1n-E)/(Tout-E)] (4)
Defining:
T . - E = cooling pond "approach" and
35
-------
T. - T = condenser AT for a closed cycle pond, equation 4 can
in out —
be rewritten as:
A _ 1230 1n /AT + Approach
A ' K ln (—Approach ;
(5)
A graphical representation of this equation is presented in Figure 7
for a 1,000 MWe nuclear power plant (nt = 33%, in-plant losses = 5%).
Q and AT values were obtained from Figure 2. Three values of K and two
"approach" levels are provided. Note that pond size decreases with
increasing values of K, AT, and approach (with all other factors being
constant). The effect of higher waste heat loads at a higher "approach"
due to an increase in plant heat rate is not represented. Figure 8 and
Table 2 provide information on the relationship between pond size and pond
inlet water temperature for various regions of the U.S. under design
summertime conditions for a 1,000 MWe nuclear power plant (TU = 33%,
In-plant losses = 5%). Mote that as the inlet temperature increases,
the required pond area decreases.
Table 2. K AND E VALUES
29
Location
Location in U. S.
Portland, OR
Dallas, TX
Bakersfield, CA
Atlanta, GA
Boston, MA
Chicago, IL
Northwest (NW)
South Central (SC)
Southwest (SW)
Southeast (SE)
Northeast (NE)
Great Lakes (GL)
1C
(Btu/ft2-
day °F)
128
202
166
132
184
203
87
92
88
98
87
89
36
-------
FIGURE 7
COOLING POND SIZE VS. AT
"APPROACH" =5° F
"APPROACH" =2 °F
K VALUES IN Btu/ft2doy °F
6000
1000
20 30
Tin-Touf,«F
37
-------
FIGURE 8
POND AREA VERSUS
INLET TEMPERATURE
3000
ATLANTA (SE)
BAKERSFIELD (SW)
PORTLAND (NW)
CHICAGO (GD*
500
110 115 120 125 130 135
INLET TEMPERATURE, IN DEGREES FAHRENHEIT
38
-------
The equilibrium temperature method is normally used to determine pond
size under design meteorological conditions. It can also be used to
evaluate pond performance under off-design conditions.
The equations presented above are for flow-through ponds. In order
to obtain a truly flow-through configuration, the water must be directed
through the pond by baffles or dikes, since the natural topography is
often not adequate to provide the proper flow configuration. In many
cases, a cooling pond will contain "dead spots" such as bays or inlets
which do not participate in the heat exchange processes. In such
cases, one should reduce the effective pond area to account for this
reduced cooling capability. Also, ponds may be configured such that
a portion is operating as a completely mixed pond rather than as a
flow- through pond. In such cases, one should evaluate the lower
effectiveness of the completely mixed portion.
Edinger and Geyer present a table relating the temperature excess
t
ratio, (Tout~E)/(Tjn"E) to tne ratio of areas for the two pond types
(mixed pond area/flow-through pond area). Figure 9 provides a plot of
these data. This figure illustrates the fact that for a given value
of E and condenser AT, the cooler the desired pond outlet temperature,
the greater the area of a mixed pond with respect to that of a flow-
through pond. < .
One can evaluate the temperature of the completely mixed portion of a
cooling pond by using the following relationship:
T = in (6)
m (123 Q + KA)
where T = surface temperature of mixed pond, °F
In using the the relationship, note that T^n is the inlet temperature to
the completely mixed portion of the pond, which may not equal the overall
pond inlet temperature. Also, A is the area of the completely mixed
portion.
39
-------
FIGURE 9
MIXED VS FLOW-THROUGH PONDS
T(OUT)-E
T (IN)- E
0.8
0.6
0.4
0.2
234
A (MIXED)/ A (FLOW-THROUGH)
40
-------
In evaluating pond designs presented in an EIS, the use of the above
relationships is preferred over the application of "rules of thumb" for
pond sizes. Meteorology plays such a dominant role in pond design that
wide variations in pond sizes can be expected for similar power plants
in different locations.
The material presented above merely highlights one method for calculating
pond size. More complete information on cooling pond size and performance
can be found in reports by FWPCA25 Hittman3, Littleton28, Brady et. al.26,
27 29
Vanderbilt , Tichenor and Christiansen , and Hanford Engineering
Development Laboratory .
* • v % • i
Water Consumption -
The computation of water consumption from cooling ponds cannot be
accomplished with simplified "rules of thumb" as is possible for
wet cooling towers. As discussed above, cooling pond operation is
dictated by all components of the energy budget and thus a simple
percentage estimate of latent heat transfer is not possible. -Two
methods are available for computing cooling pond evaporative water '
loss:
1. Energy budget - this method requires a complete evaluation of
all components of the energy budget (e.g., long and short wave incident
and reflected radiation, conduction-convection, and back radiation)
to compute evaporative water loss, knowing the pond temperature. The
reader is referred to Edinger and Geyer24 for details of such computations.
It must be noted that small variations in pond temperature can cause
large changes in evaporation, thus one should use the energy budget
method of evaporation prediction only when high confidence is placed
in the pond temperature data.
2. Mass transfer equations - this method employs empirical equations
of the form*:
QE = f(w) (es - ea)A (7)
*This is the most common form used in such calculations, however, many
other forms are available in the technical literature.
41
-------
where Qr = evaporative water loss, cfs
f(w) = wind speed function, w(wind speed) in mph
e = vapor pressure of saturated air at the pond water
o
temperature, inches Hg
e = vapor pressure in the ambient air, inches Hg
a
A = pond size, acres
The value selected for the f(w) coefficient is critical to the computation,
?4 ?fi
and several values can be found in the literature ' . The following
values of f(w) are presented in units consistent with this report:
Equation f(w)
0/1 ', "3
Lake Hefner" (2.25 x 10 )w
9A. -3
Lake Colorado City (3.31 x 10 °)w
9A. -9 -^
Meyer" 1.44 x 10 * + (1.44 x 10 J)w
Brady, et. al.26 1.38 x 10"2 + (1.38 x 10"4)w2
Figure 10 shows the relationship between QF and w for (e - e ) = 2 inches
t s a
Hg for these four values of f(w), for a 2,000 acre pond. Unfortunately,
no blanket statement can be made regarding the applicability of these
or other estimates of f(w) to a particular situation. All formulations
of f(w) given above are based on specific empirical data and none may be
strictly applicable to a given cooling pond. Historically, the Lake Hefner
2fi
function is the "most popular;" the Brady, et. al. , function was derived
42
-------
FIGURE 10
POND EVAPORATION VS WIND SPEED
QE VS. W, es-ea=2 in Hg
A =2000 acres
120 r
0
43
-------
from cooling ponds located in the Southeast and South Central United
States and is probably the "best" one to use in those locations.
When using Equation 7 to compute evaporative water loss for a flow-through
cooling pond, one should not simply use the average pond temperature,
(i.e., (T. - T .)/2) to obtain e , because e , is a nonlinear function
In UUv o w
of water temperature. A preferable method is to segment the pond into
several areas of similar temperature and perform calculations on each
segment.
Figure 11 illustrates the effect on evaporative water loss of varying • *!•,
the inlet temperature for a closed-cycle cooling pond serving a 1,000
MWe nuclear power plant. The curves in this figure were constructed
using f(w) = (2.96 x 10 )w for design summertime conditions at the
indicated locations. The data on pond areas contained in Figure 8
were also used.
t -': >
The above information can be used to estimate pond evaporation. In '
the case of cooling ponds, however, evaporation is not equivalent to [
consumptive water loss. The following considerations apply to the
evaluation of consumptive water loss.
1. Cooling ponds will gain water by direct precipitation and
runoff and possibly by infiltration. This water is subtracted from the,
evaporative loss in computing consumptive water loss.
2. If the pond existed prior to its use as a cooling facility, ,
the natural evaporation from the pond must be subtracted in evaluating-;
consumptive water loss, ? „••
3. For new ponds, the previous natural evapo-transpiration of the
area covered by the pond should be subtracted in estimating consumptive
water loss.
44
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FIGURE 11
POND EVAPORATION VERSUS
INLET TEMPERATURE
Q
CHICAGO (GL)
ATLANTA (SE)
BAKERS-
FIELD (SW)
PORTLAND (NW)
30
1
10 115
DALLAS^
(SO
1 1
120 125
•
— •
1 I
130 \:
INLET TEMPERATURE, IN DEGREES FAHRENHEIT
45
-------
4. Seepage from the pond should be added to the consumptive water loss.
As with cooling towers, the average annual consumptive water loss from
cooling ponds is substantially lower than the loss under design
meteorological and full load conditions. No simple "rules of thumb"
can be provided to estimate this difference due to the complex nature
of cooling pond consumptive loss mechanisms and regional differences
in meteorological conditions. It would not be unusual, however, for
average annual water losses to be less than half the losses under design
conditions.
Cooling ponds may require a blowdown discharge. Since no drift will
occur, Equation 2, can be rewritten as:
This equation assumes no precipitation, runoff, infiltration, or
seepage. Precipitation, runoff, and infiltration would reduce the
"effective evaporation" and lower the blowdown rate. Seepage would act
as blowdown, and thus reduce the blowdown required.
If the pond requires blowdown, the make-up requirements would equal
pond evaporation plus blowdown and seepage minus precipitation, runoff,
and infiltration.
The methodology presented above provides the EIS reviewer with one technique
for estimating cooling pond water consumption. Nomographs for computing "
o
pond evaporation are also available .
•>
Environmental Effects -
Cooling ponds dissipate a large portion of the waste heat load by
evaporation. Thus, large amounts of water vapor are discharged to
46
-------
the atmosphere. As with cooling towers, this phenomenon has the potential
for increasing local fogging and icing. Unlike cooling towers, however,
the water vapor is discharged over an extensive area and thus elevated
plumes are unlikely.
There is limited information concerning the fogging potential of
cooling ponds. Ponds do exhibit a "steam fog" directly over the surface
during cold weather periods30. Experience with such ponds indicates,
however, that this fog will not extend over the land surrounding the
pond for more than a few (i.e., 10-100) yards. However, under extreme
conditions, the fog may extend over land a mile or more. Also, steam
fogs have been observed to cause icing on the vegetation near the pond.
The icing is of a low-density, granular nature and is unlikely to cause
weight damage.
The potential for cooling pond fogging and icing increases as the
air temperature decreases, the humidity increases, and atmospheric
stability increases. The downwind distribution of water vapor can
be estimated using the dispersion calculations discussed previously
with regard to cooling towers.
In reviewing an EIS, one should consider the factors given previously
for cooling tower fogging.
Spray Cooling Systems
"**'
Operating Characteristics -
Spray cooling systems, using fixed or floating spray nozzles or spinning
discs, are available from several manufacturers. They provide cooling
by evaporative and convective heat exchange between the spray droplets
and the ambient air.
47
-------
A great deal of flexibility is available in the design of a spray
cooling system. They can be used in a canal (e.g., as designed for the
Quad Cities plant) or a pond in a closed-cycle configuration. Also,
they can be used in a canal in combination with a standard cooling
pond (e.g., the Dresden Station), they may also be used in a combination
cooling system in a discharge canal (e.g., the Chesterfield plant).
As with wet cooling towers, spray systems are designed for a specified
range and approach. The EIS reviewer may generally assume that the system
configuration provided by the manufacturer is adequate for the given
design conditions.
Water Consumption -
Evaporation from spray systems is comparable to that from wet cooling
towers except for ranges less than 10°F, and the estimates presented
previously can be used. For closed-cycle spray systems, blowdown rates
will also be comparable to wet cooling towers. Drift rates from spray
systems have not been adequately studied, however, the contribution
of drift to consumptive water loss is negligible. In summary, the
make-up water requirements and consumptive water loss for closed-spray
systems can be evaluated using the procedures given previously for wet
cooling towers.
Environmental Effects -
As with wet cooling towers and cooling ponds, spray systems have the
potential for fogging. Due to limited operating experience and minimal
research on the problem, one can only provide a qualitative judgment
on this potential. In general, under cold or humid weather conditions,
the immediate area of the spray system will probably be foggy. Normally,
this fog would not be extended over adjacent land. Extreme meteorological
conditions could cause a greater area to be covered, and the EIS reviewer
should use the techniques presented previously for cooling tower fogging
to assess such a situation.
48
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Ici"g due to spray systems is also a potential problem. Vegetation
near the system can be expected to receive a coating of low density
ice during cold weather periods; no structural damage to trees should
occur. More widespread icing is not probable; however, the considerations
presented for wet cooling towers would be applicable in evaluating extreme
conditions.
Spray systems drift rates are not generally available. In terms of
drift deposition on adjacent land and structures, two inherent characteristics
of spray systems contribute to lessening the effect:
1. Low profile - the top of the spray pattern is only about 20
feet above the water surface.
2. No vertical air movement is involved, so the drift particles
will not be carried aloft.
Also, spray systems that produce large droplets will cause fewer drift
problems than those which operate with small droplet size.
Dry Cooling Systems
Operati ng Characteri sti cs -
Dry cooling systems use only sensible heat transfer and are appropriate
in areas of little or no water. There are two types of dry systems:
1. The direct air condenser where the turbine exhaust steam is
condensed by the air and no cooling water is employed.
2. Indirect type dry systems where direct spray condensers
(Heller type) are used and the cooling water and steam are mixed, with
the resultant hot water going through an air heat exchanger. Thus,
49
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there is no separate cooling water system. Recent studies indicate
that a standard surface condenser could be used in place of a direct
spray condenser.
Several dry cooling systems are operating and under construction in
Europe; however, the only United States experience with dry cooling
for power plants is at the Simpson station in Wyodak, Wyoming. This
20 MWe unit employs a direct air condenser. An additional unit several
times this size is being planned for the Simpsom station using a dry
cooling system.
The economic and technical feasibility of dry cooling systems has been
01 n
widely reported ' . The major obstacle to their use on large power
plants in the United States appears to be the lack of suitable high back
pressure steam turbines. A wider use of dry towers in the United States
awaits the successful demonstration of a large prototype. The most obvious
use of dry systems is at fuel rich and water poor locations. Since
nuclear power plants are not generally located with respect to fuel
source, the major use of dry towers will probably be at mine-mouth fossil
fueled plants. The exception would be the use of a dry system to
alleviate environmental effects.
For information on technical and economic aspects of design and operation
of dry cooling systems, the EIS reviewer should consult an EPA report by
R. W. Beck and Associates "Research on Dry-Type Cooling Towers for Thermal
31
Electric Generation" .
Water Consumption -
Dry cooling systems have essentially zero water loss. Heat exchanger
leaks are possible, but would cause only minute water loss in comparison
to wet cooling devices.
Environmental Effects -
By the nature of their operation, dry cooling systems will not cause
50
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fogging, icing, drift, or blowdown problems. There is some controversy
over what the overall environmental effects of the warm air discharge
from a dry cooling tower might be. A beneficial effect may be to
increase ventilation in inversion prone areas. The potential modification
of local meteorology, such as triggering the formation of cumulus clouds,
requires further study. Also the overall meteorological consequences
of large heat releases should be assessed; however this problem should be
considered in the broad context of all large heat sources. In general,
dry towers can be expected to be good environmental "neighbors," with the
possible exception of noise problems.
A comprehensive analysis of the potential environmental effects of dry
cooling towers is contained in a recent report by Boyack and Kearney^2
of Gulf General Atomic Company.
yet/Dry Towers
Operating Characteristics -
Wet/dry cooling towers have received intensive study in recent years
by several manufacturers. These systems, as the name implies, are
constructed with both dry and evaporative heat exchangers. The normal
design provides initial cooling water passage through a dry heat exchanger
with the water then falling through conventional wet cooling tower
packing. Other configurations are also possible, such as separate
closed-loop cooling circuits for the wet and dry sections as proposed by
qo
Heller . To date, only mechanical draft units have been tested on a
full-scale. Single cells are operational, but no power plant operates
completely on wet/dry towers.
The purposes of utilizing wet/dry towers are two-fold:
1. To reduce or eliminate the visible plume emission by a)
decreasing the moisture content of the vapor discharge and b) heating the
plume to allow it to hold more water vapor before becoming saturated.
51
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2. To reduce water consumption. The tower designer can specify
what proportion of the waste heat load must be rejected by the dry section
and design the tower accordingly (i.e., 50% dry, 50% wet; 30% dry, 70%
wet; etc.). In general, the dry section will have a larger heat
rejection capacity than the wet section when water conservation is the
goal.
The operation of the wet/dry tower will depend on meteorological, < >
hydrological, and plant-load factors. For example, during meteorological
conditions conducive to fog problems, maximal use of the dry section will
reduce or eliminate the visible plume. During other weather conditions,
the tower may operate primarily as an evaporative cooler. Low availability
of make-up water will also require maximal use of the dry section, with
due consideration to the effect of high turbine back pressure on the
plant's capacity and efficiency (see Section VII).
As with both wet and dry towers, the EIS reviewer can assume that a
design providing a wet/dry tower for a given closed-cycle cooling
system is suitable to dissipate the waste heat. The reviewer can refer
to the previous sections on wet and dry towers for operating and design
information concerning the appropriate segment of the wet/dry tower.
Reference should also be made to information contained in the technical
literature34' 35> 36' 33. '.;..
Water Consumption -
The water consumption from a wet/dry tower will vary considerably
depending on the design (i.e., % dry vs. % wet), operation, and meteorology.
Given this information, the EIS reviewer can use the procedures described
previously for wet and dry towers to estimate water consumption.
Envi ronmental Effects -
As discussed above, fogging (and thus icing) can be controlled by the
52
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design and operation of wet/dry towers. The EIS reviewer can use the
information presented previously on fogging and icing for wet towers
to assess a similar problem for wet/dry towers. Care must be taken,
however, to include the effect of,the dry heat exchange in evaluating
the plume moisture.
Drift is caused by "mechanical" forces and is not affected by the heat
exchange in a tower. Therefore, if all of the water is circulated
through the wet section of a wet/dry tower, one would not expect the
drift rate and subsequent deposition to be much different than for a
conventional wet tower. Thus, the EIS reviewer can use the information
presented on drift from wet towers to evaluate drift from wet/dry towers
Conclusion
The material provided above on various closed-cycle cooling systems
should provide the EIS reviewer with sufficient information to assess
the great majority of power plant closed-cycle cooling systems. Unique
systems, such as fan assisted natural draft towers , and oversized
towers for fog control as proposed for the Sherburne County plant in
Minnesota38, were not discussed. However, enough general information
is presented to enable the reviewer to address such unique systems in
an informed manner.
53
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D. ONCE-THROUGH COOLING
Introduction
The increasing scarcity of water supplies adequate to accomodate large
multiple generating units, water temperature standards and mixing
zone specifications, power plant effluent limitations, and the national
goal of eliminating industrial waste discharges will tend to preclude
once-through cooling for most new plants that use fresh water. In the
remaining fresh and salt water cases, evaluation of the applicant's
methods, findings and conclusions are required.
Data to support proposed once-through "cooling may be in the form of
physical model results, mathematical model results, transposition of
data from an existing plant to an undeveloped site, or combinations of
these. Although data transposition can complement model data, it
will seldom stand alone in marginal cases because of physical, hydraulic,
and plant dissimilarities between sites. So we turn here to physical and
mathematical models.
The first question in evaluation is the suitability of the applicant's
model to the case at hand.
Applicability of Models
Unfortunately, models are not always made to behave identically to
their natural counterparts (that is, to their prototypes). The
reasons are these: (a) Even if it were possible to formulate most
general mathematical models so that they closely resemble nature,
they would (1) become too difficult to solve mathematically, and
(2) would depend on certain inputs that are not easily available;
(b) Physical models can be made to closely reproduce the behavior of
54
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a prototype only if they are made as large and as complicated as the
prototype itself.
For the reasons mentioned above, all practical models, whether mathematical
or physical, are simplified so that (a) they become amenable to analysis,
and (b) they are economically feasible to build and operate. Nevertheless,
if simplification is made at the expense of those very processes in
nature that the models are assumed to imitate, then the benefit derived
from such models is limited proportionately to the sacrifice made to
arrive at simplification. This should not imply that good models
must be necessarily complicated, but it does mean that (a) a simple
model can be developed to represent and predict reasonably well few
(but not all) particular processes in nature, and (b) a complicated
model may fail to predict a simple process if not properly applied.
In short, it is always important to examine all assumptions used
in developing a model and to guard against applying the model to
situations they are not intended to represent.
38a
A report by Silberman and Stefan discusses the attributes and
limitations of physical modeling. Where boundary conditions are
complex or mathematical models are otherwise unreliable, an applicant
seriously proposing once-through cooling should provide physical
model data along with sufficient description of the model and studies
for EPA evaluation.
In general, mathematical analytical techniques can be classified
with respect to submergence of the discharge.
Deep submergence implies the absence of extraneous effects, such as
proximity of the water surface and the ocean or river floor or any
wall or barrier that might affect the plume trajectory. The jet
must be submerged at least 40 or more diameters deep. Reference
39 provides a useful compilation of numerous practical analyses of
this discharge category.
55
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In a shallow discharge the effects of such disturbances as the bottom,
water surface, and downstream flow conditions are accounted for
either analytically or experimentally. Examples of vertical discharge
in shallow water without current are given in Reference 39. Reference
40 is a comprehensive review of shallow discharges and provides analysis
and experimental results of multiport diffusers. Reference 41 deals
with single jet discharges. It contains limited but useful data.
State-of-the-art information on surface discharges is presented
in Reference 42. Reference 43 is a User's Manual for surface discharges
and Reference 44 is a compilation of recent data.
Generalizations on Plume Behavior
Thermal plume behavior depends on characteristics of both the receiving
water and the discharge. Plume analysis is primary a matter of
hydraulics (mixing); heat exchange between water surface and atmosphere
usually, but not always, plays a relatively minor role in the location
of isotherms less than about A2°F.
Inasmuch as receiving water charactersitics at a site are generally
fixed whereas discharge characteristics are variable, the former-
imposes the first set of limitations on designing an acceptable once-
through discharge.
The following is a listing of some possible receiving water characteristics
that affect mixing:
a) The ambient water could be i) nearly motionless, such as in
a lake, ii) flowing, such as in a river, or iii) intermittent, ,
such as tidal waters.
b) The water body may be without temperature or salinity
stratification or partially or totally stratified.
56
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c) The water basin near the discharge may be deep and vast or
there may be effects of boundaries, such as shoreline and
bottom slope.
d) The ambient water may be influenced by the action of wind.
This effect may be very strong or negligibly small at times.
. •' ''
Pertinent discharge characteristics include:
a) Submerged or surface discharge. ; .
b) Discharges from single or multiple round ports or from a
rectangular port.
c) Discharges from an open channel or a closed conduit.
d) Discharges in the general direction of the current, cross
current, counter current, or other angles. '
e) Discharges in a vertical, horizontal, or inclined direction.
f) Generally uniform and constant discharges or intermittent
and time varying discharges.
Other factors being equal, the greatest degree of mixing can be accomplished
with multiple port discharges in deep water. This is usually preferred
from a biological standpoint because the smallest volumes of water are
subjected to excess temperatures for the minimum length of time.
Stratification with little or no mixing can result from a surface
discharge from a channel. In rivers, such heated surface layers are
usually not acceptable if they cover a major portion of the river
width. A high velocity discharge into a cross current may in some
cases cause too much penetration and blockage of the waterway, thus
preventing the natural migration and other activities of fish. For
this reason, discharges at an angle may be more desirable.
57
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In the majority of situations, it is desirable to locate the discharges
at some distance downstream of the intake; also when there is no
predominant ambient current, to locate the discharges at a higher
elevation than the intake, in order to avoid or eliminate the possibility
of recirculation.
Once-through discharges using ocean water often require large diameter
pipes extending hundreds or even several thousand feet into the ocean
to reach deeper waters so that shallow coastal waters are protected
from excess heated water. Such pipes are often made of concrete and
they can be more than ten feet in diameter. Typical jet diameters
for single port discharges may be on the order of ten feet and for a
multiple port discharge, on the order of one foot. Typical dimensions
of a surface jet channel may be up to one hundred feet wide and up
to 30 feet deep. Typical discharge velocities from a submerged jet are
6 to 17 ft/sec and for surface discharges, 1 to 6 ft/sec. Excess
temperature is on the order of 15 to 30°F depending on the waste heat
load and the flow rate used.
The interaction of the plume with the ambient water results in the following:
a) dilution is enhanced by the turbulence in the ambient current,
by wind, and by a high velocity discharge into a current,
b) plume rise from a submerged discharge is delayed by ambient
current, and by jet inclination,
c) plume rise can be totally terminated in a stratified environment,
d) the discharge from the shore into a river can result in deep
penetration if the jet velocity is much greater than the
river current—otherwise the plume hugs the shoreline,
e) the plume width is generally greater in stagnant water than
in moderate currents.
58
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Water Consumption
The amount of water consumed by wet cooling devices (see information
presented in Section IV-C) is often noted as an adverse effect. This
may or may not be true, depending upon the local availability of water.
A point often overlooked, however, is the fact that once-through
cooling systems also cause water consumption (i.e. evaporation) to
occur. A significant portion of the waste heat in the discharge is
ultimately transferred to the atmosphere by latent heat exchange at
the water surface, which incidentally, may cause a "steam fog" to
occur. For example, a once-through cooling system for a 1000 MWe
fossil plant on Lake Michigan could cause an annual average
evaporation loss in excess of 8 cfs . The EIS reviewer should make
sure that a value for this evaporative loss is provided, to assist in
both his assessment of the system and his comparison of alternatives.
Suggestions for Review
Although certain deviations may be necessary, the following checklist
and approach have been useful.
1. The reviewer should familiarize himself with the general
topography of the site, particularly with respect to the water body
that is being used as the source of cooling water and as a recipient of the
heated effluent. Important items to be reviewed are:
a) ambient flow conditions, such as the velocity, flow rate,
tidal exchange and tidal prism, etc.,
b) water depth at the discharge and intake as well as the
general depth contours,
c) seasonal variation in flow, particularly the extreme (such
as the 7-day, once in 10-year occurrance) and average conditions
as obtained from past records, and
d) the ambient weather conditions, particularly the presence of
prevailing wind and severe or extreme climates.
59
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2. The reviewer should then briefly check the applicant's
calculation "for the flow rate at a given AT against the quantity
of heat that the plant is expected to release. The following equation
can be used:
Q = 0.00445 (WH) (P)/AT (9)
where Q = Flow rate, cfs .
WH = Waste heat,to cooling water, Btu/KWH
P = Plant size, MWe.
AT =. Cooling water temperature rise., °F
•. <•,,. - •
Figure 2 is a graphical representation of this equation.
3. Some of the preliminary environmental considerations can
be sized up at this point, as follows: .
a) compare the relative flow rate of the ambient water against
the discharge. If the river flow or tidal exchange is,
say ten times the discharge rate or less, then the assessment
of the physical impact, if not already obvious, should be :
reserved for further detailed examination,
b) check if the discharge is reasonably well extended into the
deeper waters, , . ,
c) check if there is obvious scouring of the bottom or obvious
plume hugging of the shoreline,
d) check for minimum length of piping ahead of the diffuser to
see if the exposure time to heat could be minimized—note also
the competing results from c) and d),
e) examine some of the results, such as centerline temperature,
plume dimensions and plume areas enclosed by specified isotherms
If in the above considerations, the following are observed, closer
examination is needed:
60
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a) if the plume area is relatively large compared with the gross
water surface area near the discharge,
b) if the topography is very complex, such as shorelines, bends,
etc.,
c) if there is tidal fluctuation, and
d) if there is the possibility of a sinking plume. The latter
possibility could present itself if the discharge water is
more saline than receiving water, or if there is temperature
stratification under winter operating conditions, such that
the discharge could be locally more dense than the receiving
water anywhere along the trajectory of the plume.
4. There are situations where the reviewer may form a definite
idea at this point as to whether or not the once-through system is an
acceptable alternative. This happens only when there are clear
indications of environmental acceptability of the plan or a clear
indication of lack of such acceptability. In the other cases, however,
a more detailed study may be required.
It should be pointed out that a complete analysis of once-through
systems requires expertise in several disciplines including engineering,
economics, and biology. Important factors in all these disciplines
dictate the method of discharging heated water from a once-through
system. Among the factors to be considered in selection of one method
of discharge over another are:
a) environmental impact,
b) temperature criteria,
c) cost,
d) cooling performance, and
e) cooling water recirculation.
61
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E. COMBINATION COOLING SYSTEMS
Operating Characteristics
Combination cooling systems have characteristics of both closed-cycle
and once-through systems. Although terminology often differs, the
"helper" category includes any of the cooling devices discussed previously
in this section to recirculate any portion (0-100%) of the cooling water
requirement. The operating mode is determined by the temporal characteristics
of water supply availability, water temperature, meteorology, and by
applicable water quality standards. Another combination system uses a
"terminal difference" or auxiliary cooling device which removes a portion
of the waste heat from a once-through system.
Cooling systems involving helpers should be reviewed carefully, inasmuch
as the tempting by-pass option is always present. In terms of economics,
any advantage of helper over closed-cycle for optimized new plants is
marginal due to the interrelationship of the turbine condenser and
234
cooling device ' ' . For retrofitting an economic advantage may exist.
In any event, the economic analysis must be approached on a case-by-case
basis.
One problem with helpers is the inadequacy of the management (decision
making) system in comparison to the versatility of the hardware. While
theoretically a helper system can be tuned and operated so that the
discharge quality will "just meet" water quality standards or effluent
limitations, a rather sophisticated in-stream and in-plant sensing
network coupled with a conditional probability program is required to
turn the right valve at the right time. We have not seen such a system
described in any environmental impact statements reviewed.
An EIS on a helper system should contain the following information:
1. The percent of time the cooling device will be operated.
62
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2. The operation schedule throughout the annual cycle.
3. The amount of waste heat removed with respect to 1 and 2,
above.
4. How the operation according to 1 and 2 above will affect
the water consumption, fogging and icing potential, drift, and blowdown
(if any).
The consent decree in the case of Houston Lighting and Power versus
Ruckelshaus, et. al. allows an auxiliary system. In this instance, a
cooling pond on a once-through cooling system dissipates a seasonally
variable fraction of the waste heat from the condenser effluent for
discharge into Trinity Bay.
Practical cooling limits of evaporative auxiliary systems, as related
to equilibrium temperature and evaporation rate or wet bulb temperature,
should be examined throughout the annual cycle. A system that can meet
water quality standards in the summer, under design conditions, frequently
will not in the winter if such standards limit the temperature rise
above ambient temperature. Figure 12 exemplifies seasonal variations
in cooling pond efficiency near Galveston Bay, Texas for an auxiliary
pond on a 1,500 MWe fossil fueled station.
For cooling towers, an approach to wet bulb temperature of less than 10°F
is rarely achieved under design conditions and certainly the approach
is never less than 5°F. Therefore, to determine the effectiveness of
auxiliary cooling towers on a once-through system, one can compare the
practical cooling limit, (wet bulb plus approach) to the receiving
water temperature. Table 3 provides such a comparison for the same
geographical area. Note that through much of the year a tower effluent
would be appreciably warmer than the receiving water.
63
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FIGURE 12
SEASONAL PERFORMANCE OF AN
AUXILARY COOLING POND FOR A
1500 MWe FOSSIL FUELED
POWER PLANT
[22,500
o
CO
o
o 1,500
Q_
1,000
JAN.
(AVE)
JULY I JULY
(AVE.) I (EXT.)
JAN.
(EXT.)
4 6 8 10
AT FROM POND,°F
12
NOTES*
T IN= E+20°F
T OUT = E+ AT FROM POND
AVE. = AVERAGE METEOROLOGICAL CONDITIONS
EXT= EXTREME METEOROLOGICAL CONDITIONS
64
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Table 3. COMPARISON OF MECHANICAL DRAFT TOWER COOLING LIMITS
TO RECEIVING WATER TEMPERATURE
Receiving Water
Cooling Limit (°F) Temp (°F)
Month 5°F Approach 10°F Approach Average Maximum
Jan
Feb
Mar
Apr
May
Jun
Jul
Aug
Sep
Oct
Nov
Dec
73
73
75
79
83
86
85
85
85
85
83
78
78
78
80
84
88
91
90
90
90
90
88
83
56
53
62
72
80
84
86
86
85
72
72
55
63
60
67
80
86
86
90
90
90
79
76
64
65
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When air and water temperatures drop, prudence imposes another lower
practical limit on tower effluent. Regardless of meteorologic limits
on cooling capability, no plant superintendent is going to run a tower
with a cold leg anywhere close to freezing temperatures because of the
hazard of tower icing, which can be very costly.
Any wet cooling device can be used in a combination system for either
an original design or a backfitted situation. For backfitted systems,
the design and construction flexibility of spray systems is often
overlooked in the EIS.
Water Consumption
The amount of water consumed by a combination cooling system will be
governed by the same factors discussed previously for closed-cycle and
once-through cooling systems. The EIS reviewer can compute the total
water consumed on a design and annual basis using the procedures given
previously coupled with information on the percent of waste heat
dissipated and the seasonal operating schedule.
Environmental Effects
The environmental effects of combination systems can be assessed using
the techniques described previously for closed-cycle systems. The
operational characteristics of the combination system may ameliorate some
environmental problems (e.g., reduced use of cooling towers in cold
weather will lower probability of fogging and icing problems). On the
other hand, an auxiliary cooling tower will increase the time-temperature
exposure for entrained organisms and probably cause more damage to such
organisms. Thus, the fact that an auxiliary cooling device will permit
water quality standards to be met does not insure an improvement in the
environmental acceptability of the cooling system.
In summary, any proposed combination cooling system should be viewed,
initially at least, with judicious scepticism.
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SECTION V
CHEMICAL, BIOCIDAL, AND SANITARY WASTES
Numerous chemical wastes and other effluents are generated during
startup and normal operation of a nuclear power plant. Many of these
effluents are totally independent of the type of cooling system utilized;
however, it is common practice in most cases to combine these effluents
with the cooling water or blowdown discharges at some point before
final release. Therefore, although the quantity of many constituents
is unrelated to the cooling system choice, the concentration of the
constituent in the discharge stream may well be determined or influenced
by cooling system choice and operating characteristics.
Although the combining of effluent streams before discharge is a common
and acceptable practice, the dilution effect should not be pursued as
a substitute for treatment of wastes prior to discharge. Since the
quantity of blowdown is governed by the cycles of concentration in a
closed-loop system (i.e. low C, greater blowdown volume), the reviewer
is encouraged to assess carefully the reasons for running at the
proposed number of cycles, especially if the C value appears excessively
low. Cycles of concentration should be governed by water quality
limitations as described in Section IV-C and should be as high as possible.
Treatment of wastes may be required before dilution with other effluent
streams.
Radioactive wastes and most toxic wastes are processed through the
radwaste system. The following discussion is primarily oriented toward
other wastes, from the plant or from cooling water treatment, which the
reviewer should survey in connection with cooling system alternatives.
Sanitary waste treatment is usually dictated by State requirements, to
which conformance is normally verified quite easily.
67
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Only a few of the most common chemical pollutants are cited herein
because of the great variability of treatment requirements (and resulting
effluent characteristics) occurring from site to site. The best approach
for the reviewer is to carefully assess: (1) The quantity of each
constituent added for plant operations, and (2) the before/after comparison
of the concentrations of any constituent causing potential pollution
concern. Resulting constituent levels in discharge effluents should
then be compared with Water Quality Standards or applicable effluent
requirements or pertinent information which may indicate the reasonableness
or environmental acceptability of proposed discharges.
i . _ t ,t ,i
Liquid wastes with pollution potential emanate primarily from condenser
cleaning, water treatment, and blowdown operations.
An important area to review is the method of control of biological
growth in the condensers. Periodic addition of chlorine is an effective
method of control which has been widely used in the power industry.
However, the toxic effects of chlorine or chlorine derivatives to
aquatic organisms require minimization and close control of these
constituents in effluent discharges. When chlorination is proposed, the
length of time and the concentration of residual chlorine (free and
combined) in discharges should be reviewed for compliance with recommendations
45
by Brungs , which follow in Table 4. It should be noted that these
recommendations apply only to freshwater aquatic life and that the criteria
vary according to time factors and type of organisms.
68
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Table 4
RESIDUAL CHLORINE RECOMMENDATIONS, from Brungs45
TYPE OF CHLORINE USE
CONCENTRATION OF TOTAL
RESIDUAL CHLORINE
DEGREE OF PROTECTION
Continuous
Intermittent
A. Not to exceed
0.01 mg/1
B. Not to exceed
0.002 mg/1
For a period of
2 hr a day,
up to, but
not to exceed,
0.2 mg/1
For a period of
2 hr a day,
up to, but
not to exceed,
0.04 mg/1
This concentration
would not protect
trout and salmon and
some important fish-
food organisms, it
could be partially
lethal to sensitive
life stages of
sensitive fish species,
This concentration
should protect most
aquatic organisms.
This concentration
would not protect
trout and salmon.
This concentration
should protect most
species of fish.
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If proposed chlorination practices are deemed unacceptable, various
approaches may be applicable, depending on the situation, for further
control, including:
(1) Practicing split stream chlorination, i.e. treating one condenser
at a time.
(2) Reducing the chlorine feed period.
(3) Combining a discharge stream with another in-plant stream
which has a high chlorine demand.
(4) Discontinuing blowdown during periods when residual chlorine
is present in the cooling tower sump.
(5) Decreasing the rate of chlorine addition during feed, in
proportion to the reduction of chlorine demand of recirculating water
in closed-cycle systems. This method maintains a constant residual
chlorine level at the condenser discharge.
(6) Adding sodium sulfite, sodium bisulfite, or sulfur dioxide
to blowdown to reduce residual chlorine.
46
A recent report by Nelson provides specific information on evaluating
many of these control techniques.
A different type of control from those cited above is that of mechanical
cleaning of condenser tubes which, from an environmental standpoint,
is the preferred method because no chemicals are employed. Balls
(Amertap System) or brushes (MAN System) are passed through the condenser
tubes periodically to cleanse them of biological growth. Mechanical
cleaning is being used in numerous instances, particularly in new
plants where it can be incorporated into the initial design. Mechanical
cleaning may promote better heat transfer efficiency; disadvantages
include installation and maintenance problems and potentially higher
costs than chemical cleaning. Also, the condenser alone is treated
whereas chemical cleaning affects the entire cooling system.
70
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Boiler water treatment wastes include demineralizer regenerant wastes,
filter backwash and coagulant sludge blowdown. In this category total
dissolved solids (mostly sodium sulfate) are most notably increased.
Steam generator blowdown may contain phosphate loads which could affect
receiving water nuisance growth potential. Morpholine, a pH control
agent, might also be present in this blowdown and has potential adverse
aquatic effects.
Cooling tower blowdown will contain constituents in the makeup water
and materials in the recirculating water which are scrubbed from the
air and concentrated due to continual water evaporation by the cooling
tower.
Other chemicals may be added infrequently or in small amounts for various
purposes during plant operation. These can include deposit control
agents (which may contain nitrogen or phosphorous), cleaning agents,
•or proprietary biocides, as required.
Corrosion control may be required in a very small number of cases,
primarily those with high chloride concentrations in the circulating
water. Generally, however, corrosion is not a significant factor because
potential problems can be averted through proper choice of corrosion
resistant materials or coatings. Where protection is required, chromate,
zinc, or phosphate based inhibitors may be proposed. Their presence in
blowdown waters requires careful assessment with regard to permissible
concentration levels and potential reduction and/or removal.
The assessment of the above general or unpredictable plant wastes must
be approached on an individual constituent basis, as mentioned previously,
Waste characteristics and potential impact will vary from site to site,
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depending on source and receiving water quality, system type and operating
procedures, required treatment, discharge procedures, etc. Common
waste sources and constituents are covered here to orient the reviewer
toward potentially significant areas, but individual parameters must
be viewed in the context of applicable regulations and/or practical
alternatives or treatment for the given situation.
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SECTION VI'
ALTERNATIVE COOLING SYSTEMS
*i -i
' '' - '• ' J i • :
^ f
The reviewer's objective in this area is basically three-fold: (1)
to assure that all feasible cooling system alternatives are included
in the EIS presentation, (2) to assure that alternatives are described
accurately and thoroughly, and (3) to judge the validity of the applicant's
proposed choice when compared to the alternatives described.
The AEC's Regulatory Guide 4.2, "Preparation of Environmental Reports
for Nuclear Power Plants" provides guidance to applicants for presenting
information which forms the basis of the EIS. The following excerpts
from this guide are cited below to indicate the intent and scope of
the coverage of alternatives:
"The applicant should ... show how the proposed plant design was
arrived at through consideration of alternative designs of identifiable
systems and through their comparative assessment."
"The applicant should limit the discussion to those alternatives
which the current state-of-the-art indicates are technically
practicable."
"The discussion should describe each alternative, present estimates
of its environmental impact and compare the estimated impact with
that of the proposed system."
"Environmental effects of alternatives should be fully documented."
73
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"The acquisition and operating costs of individual systems and
their alternatives (as well as costs of the total plant and
transmission facility and alternatives) are to be expressed as
power generating costs."
If cooling system alternatives are described in full accordance with
the context of the above instructions, the reviewer will have little
problem in meeting his objectives. He should, however, follow a general
stepwise procedure in his overall assessment.
The reviewer is referred to Section V - C for the description of devices,
in addition to once-through, which are technically feasible under the
current state-of-the-art. However, this does not imply that all of
the systems described must be considered as viable alternatives for
every situation.
Technical infeasibility may be established in instances where physical
or operational design flexibility does not exist. For example, dry
cooling towers are usually not applicable to backfitting situations,
i.e. existing plants or those in design/construction stages where a
turbine is on order. Space availability may also preclude consideration
of certain control devices, most notably cooling ponds which require
large land areas. Meteorological hazards may be a governing condition,
e.g. natural draft towers may likely be excluded in areas of high hurricane
potential. These examples indicate that there are a multitude of valid
reasons why some devices are not feasible in some cases. The reviewer
is encouraged to use the devices described in Section V - C as a check-
list; if these devices are not presented as alternatives, he should
look for valid reasons for their exclusion.
74
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The description of each of the alternatives must be accurate and complete
enough to permit an unbiased comparison of potentially applicable systems.
Again, the reviewer is referred to the detailed technical and economic
considerations for each system as presented in respective sections
of this guide. Considerable judgment must be exercised in determining
exactly what information must be included. Although the system characteristics
discussed elsewhere should be used as a check-list, it is not possible
to set absolute coverage requirements. There is a tendency in some
EIS presentations to provide extensive coverage of the proposed system and
lesser coverage of alternatives. It is the responsibility of the reviewer
to see that each valid alternative is addressed in a manner which satisfies
his evaluation needs. If he feels that inadequate information is provided,
it should be expressed in review comments.
The ultimate purpose of reviewing cooling system alternatives is to
support or challenge the applicant's choice. This decision must consider
the overall relative implications of each system. Individual systems
all have their own merits and disadvantages, so that a clear-cut choice
is not always apparent. In the end, the reviewer's recommendations,
comments, or conclusions should be based on a reasonable balance between
technical/economic feasibility and environmental impact, as revealed
through his review process.
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SECTION VII
BENEFIT-COST ANALYSIS
The objective in this area of review is to assess, verify, and compare
the economic implications of various cooling system alternatives. ?
The emphasis is, therefore, placed upon incremental values associated
directly with specific cooling systems rather than the absolute magnitude
of basic factors which are not affected-by the cooling system choice,
such as the value of power to be sold or the cost of the basic plant
excluding cooling system choice. In general, the EPA technical review
is not concerned with other alternatives, such as alternative methods
of providing power.
BENEFITS
, ' .. •' * "'.".. /• .„ i . ' •"
The single direct benefit from a proposed power plant is represented
by the total revenues to be obtained from sale of electrical energy*
steam, or other products produced by the plant. In most cases the
product will be electrical power and the amount to be generated will
be specified, regardless of the choice of cooling system. Although
the present value of this benefit can be checked rather easily, it
is not necessary to do so for review purposes. It is important to :
recognize, however, that this is the single direct benefit from the
proposed plant. Any other benefits that might be cited, e.g. taxes;
employment, research, regional products, etc., are already covered
by the single direct benefit. If these types of indirect or secondary
benefits are attributed to the plant, they should be labeled as such.
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COSTS
The review of the cost analysis related to cooling system alternatives
is not a clear-cut approach, since judgment must be applied throughout.
The basic reasons for this are as follows:
t.
(1) Various environmental effects (costs) associated with different
cooling systems cannot easily be monitized. Therefore, one can
not adhere to a strict $to$ ratio for comparisons and the review
may approach more of a net cost ranking of alternatives than an
absolute quantification.
i
(2) Equipment and operating costs attributable to specific
cooling systems are not easily identified for comparative purposes.
(3) The degree of committment to a proposed plant design can
alter the benefit-cost analysis. For example, if sizeable
expenditures for design and construction have occurred, a cost
analysis of alternatives is strongly biased toward the chosen
system since others would incur the cost penalty of "scrapping"
the system under construction.
The proposed plant and cooling system design serves as the reference
design case in an EIS cost analysis. Monitary costs of alternative
systems are presented in terms of incremental generating costs, on
a total present worth or annualized basis, as compared to the reference
design. Incremental generating costs reflect the combined effect
of all fixed and variable cost differences from the reference design.
An EIS will usually not provide the extensive background information
which would be needed to individually reconstruct the two components
of the incremental generating cost. However, in the majority of reviews
77
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it will not be necessary to attempt cost verification through such
a complex procedure. The approach here will be to first provide the
reviewer with general guidelines by which the reasonableness of incremental
costs may be judged for the majority of cases. Secondly, a brief
discussion of the scope of a detailed verification is presented along
with numerous referenced sources of additional information pertinent
to such a review.
Generalized Cost Verification Procedure
The information presented in this section will usually suffice for
reviewing the following cases:
(1) When the base design and alternative cooling systems being
considered are closed-cycle.
it
(2) When the proposed cooling system for a new plant is undoubtedly
desirable in terms of minimized environmental effects. In this
case, the outcome of the monitized cost comparison is of secondary
importance.
(3) When plant construction has progressed to the point where
"sunk" costs bias or control the benefit-cost ratio. In this case,
it is obvious that monitary considerations alone will not indicate
that a complete change in cooling system design is desirable.
Environmental acceptability with minimum added cost must be sought.
In the EIS, the total capital cost of the reference plant may or may
not be broken down into costs for the basic plant and costs for the
cooling system. The basic plant cost, excluding the cooling system,
varies greatly with site, design, and economic conditions and need
78
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not be challenged. Where capital costs of cooling systems alone are
identifiable, one can compare the reasonableness of the costs with
the typical values for new plants cited in Table 5.
Table 5. CAPITAL COSTS FOR NUCLEAR PLANT COOLING SYSTEMS47
Once-through system: 3 to 5 $/KW
Natural draft cooling towers: 9 to 13 $/KW
Mechanical draft cooling towers: 8 to 11 $/KW
Cooling pond: 6 to 9 $/KW
Spray system*: 7 to 10 $/KW
The values cited above do not reflect operating penalties of the systems
and therefore, cannot be used as a primary judgment factor. However,
the capital cost comparison should be used as a first-cut evaluation
which may identify systems requiring more detailed scrutiny.
The once-through system costs cited herein, later used as the basic
or reference case, reflect a more-or-less typical or uncomplicated
once-through situation. Long outfalls with diffusers can be quite
costly, depending on site-specific factors. Economic data on long outfalls
and diffusers are limited, but the following design-cost studies on
existing installations are mentioned here to provide a feeling for
the magnitude of costs which might be quoted.
* Independent estimates, not in reference.
79
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48
In 1967, Parkhurst, Haug, and Whitt of the Sanitation Districts
of Los Angeles reported on five major outfalls on the Pacific Coast.
Their tabulation includes trunk diameters up to 12 ft, overall lengths
up to 22,000 ft, and depths of discharge in excess of 200 ft. Costs
range from slightly over $100/ft to almost $500/ft. The cost data
are probably low by today's scale.
A 10 ft diameter steel sewer outfall running 18,000 ft out into Lake
Ontario from Rochester, New York, is described in the September 17, f
49
1970, issue of Engineering News Record . The cost reported is 18.7 ;
million dollars, or about $1,000 per ft.
50
Kempf and Fletcher report on the effects of site selection on the
capital costs of nuclear electric plants. They cite design data typical
of construction costs for discharges on the West Coast. Overall unit
costs range from $233 to $872 per ft, depending partially on trunk
diameters, which range from 7.5 to 14 ft.
A more sensitive approach for judging cost reasonableness is to look
at the magnitudes of incremental generating costs presented for the
alternatives. As noted earlier, incremental generating costs reflect
all capital and operating cost increases attributable to a cooling
system; the percent increase is, therefore, also comparable to calculated
increases in busbar costs for a given plant output.
In the EPA analysis of cooling system alternatives for new nuclear power
4
plants near Lake Michigan , the maximum busbar cost increases were
determined, as cited in Table 6:
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Table 6
BUSBAR COST INCREASES-COOLING SYSTEMS
FOR POWER PLANTS NEAR LAKE MICHIGAN
Type of Cooling System Percent Busbar Increase Over Reference
Once-through (Reference)
Cooling Pond < \%
Wet Mechanical Draft Tower 2%
Wet Natural Draft Tower 3%
Since incremental generating costs may be expressed in either total
present worth or annualized figures, the reviewer should be careful
to use consistent bases when calculating the percent increase over
total generating cost. Regardless of the choice, the percentage increase
in generation cost due to respective cooling systems should generally
correspond to the percentages cited above for new plants of optimized
design.
Another way of looking at the magnitude of costs attributed to cooling
systems is to express the cost difference from the reference design
in terms of mills/KWH of electricity produced and them compare these
figures with recent study results reflecting busbar cost variations.
One should use annualized incremental generating costs between each
pair of cooling systems being compared, thus:
81
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AMills/KWH = [A Annualized Cost. $] x [1000 Mills/Si
[Plant capacity, KWe] x
[Annual Plant Factor,56/100] x [8760 hr/yr]
Table 7 contains referenced results of busbar cost increases for new
plants, compared to once-through, which can be used in comparing the
relative magnitudes of busbar cost differences in mills/KWH:
Table 7
RELATIVE BUSBAR COSTS (Mills/KWH)
FOR NUCLEAR POWER PLANT COOLING SYSTEMS
Once-through Cooling Mechanical Natural
Sources Fresh Water Salt Water Pond Draft Tower Draft Tower
51
Woodson
EPA4
CO
Mauser0*
+0.08
+0.06
+0.3 +0.09
+0-11
+0-14
+0.21
+0.22
+0.22
+0.20
The variation in the values cited above is worth noting. It points out
the fact that one cannot go too far in evaluating cooling system costs
of a specific plant by comparing them to general norms. However, the
above costs do establish a relative level for reasonable incremental
cooling system costs. Deviations from these levels may well be justified,
but the reviewer is encouraged to investigate the reasons behind gross
deviations.
One reason for differences in values given above is that penalties for
various cooling systems are based on varying assumptions. Two cost
penalties often identified specifically in EIS cost analyses are:
82
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^ Capability loss (or capacity loss), which occurs when higher
condensing temperatures, determined by the type of cooling system and
meteorological conditions, cause higher back pressure on a turbine at
full-load and reduce its output. Capability loss occurs only when the
turbine's rated capacity can not be attained due to high back pressure.
(2) Added fuel cost (or effeciency loss), which is also a result
of high turbine back pressure because it increases the heat rate (Btu/KWH)
of the turbine for any level of output, thus more fuel is required to
generate a KWH of electricity.
Costs for capability loss and added fuel cited in an EIS Benefit-Cost
Analysis can have a sizeable impact on the economic feasibility of the
systems involved, and it is important to have a gauge of their reasonableness.
f-Q
The work of Hauser also includes an incremental cost breakdown (in
mills/KWH) for capability loss and for added fuel cost for new plants.
Table 8 presents this information along with an additional column
showing the magnitude of annual costs represented by these two penalties.
The annual costs were calculated by using the formula for A mills/KWH
given above and from Mauser's assumptions of a 1000 MWe nuclear plant
operating with an 80% plant factor.
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Table 8
COSTS OF CAPABILITY LOSS AND ADDED FUEL
ATTRIBUTED TO VARIOUS COOLING SYSTEMS
Type of Cooling System
Combined
Capability Loss Fuel Cost Annual Cost
(Mills/KWH) (Mills/KWH) (1000 MWe Plant)
1.
2.
3.
Fresh Water (Once-
through)
Cooling Ponds
Sea Coast (Once-
Base
0.0300
Base
0.0240
Base
380,000
through) Base
4. Wet Cooling Towers
Mechanical Draft 0.0300
5. Wet Cooling Towers
Natural Draft 0.0300
6. Dry Cooling Towers 0.1590
Base
0.0240
Base
380,000
0.0300 380,000
^
0.1272 2,000,000
As with other cost values presented herein for comparisons, it is
important to realize that these figures are given to indicate reasonable
cost levels; values for specific plants can vary considerably from
site to site. Also, these figures were calculated in 1970. for new
plants; hence, normal cost escalation should be taken into account.
These factors do not detract from the intended use of the figures for
guideline purposes, however.
Scope and References for Detailed Cost Verification Procedure
In a relatively small number of cases the validity of costs projected
for various cooling system alternatives becomes paramount. This situation
is usually encountered when a proposed once-through cooling system
84
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is questioned or challenged on environmental grounds while the applicant
is attempting to justify his proposed choice, partly on the basis of
economics. If the reviewer is faced with such a situation the benefit-cost
analysis requires a thorough verification not only of the final figures
presented but also of the values, assumptions, and procedures used in
determining the costs cited for considered systems.
It is beyond the scope of this presentation to cover the multitude of
assumptions, inputs, and calculations required for verifying a cost
analysis in detail. Table 9 provides sources of more detailed
information on procedures and economic factors. The EIS reviewer is
urged specifically to obtain reference 3, which provides nomograph
solutions for many of the cost estimates required.
Table 9
REFERENCES FOR DETAILED ECONOMIC REVIEW
Subject References
1. AEC recommended approach for 1
benefit-cost analysis.
2. Plant and/or cooling system 3, 4, 52, 53
economic analysis procedures.
3. Plant and/or cooling system costs. 3, 4, 53, 55, 60
4. Fuel Costs. 3, 4, 53, 55, 59, 60
5. Production Costs. 3, 4, 53, 55, 60
6. Backfitting Costs. 3, 4, 56, 57, 58
85
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Backfitting Costs
The reviewer will need to familiarize himself completely with power
plant economics to do an acceptable job of reviewing an EIS benefit-
cost analysis in detail. Many site specific factors arise with respect
to individual plants which necessitate such familiarity for valid
judgments to be made. A good example is for backfitted situations.
Estimates on the cost of backfitted cooling facilities are available
for a large number of specific plants. These data are, for the most
part, contained in utility environmental reports and AEC draft environmental
impact statements. The most striking aspect concerning these data is
the lack of consistency in the methods of reporting. This results in
widely different cost estimates. For example, total capital cost data
for backfitting power plants on Lake Michigan reported by Argonne
National Laboratory ranged from $19.4/KW to $95.7/KW for wet towers.
Assuming a fixed charge rate of 14 percent and a plant load factor of
82 percent, the increase in busbar cost would be 0.38 and 1.86 mills/KWH,
respectively. Thus, these backfitting costs differ by a factor of five.
In computing the increased busbar cost due to backfitting, care must be
taken to use realistic values for plant capacity factor and fixed
charge rate, since a short amortization period will increase the fixed
charge rate. Reducing the capacity factor and/or increasing the fixed
charge rate will increase the busbar cost differential for the same
total capital cost differential.
While no single value for backfitting costs can be given with assurance,
in general increased cost for retrofitted cooling systems will be from
two to three times the increase in costs for optimized cooling systems
given previously for new plants. On the basis of literature information,
Tichenor estimates that:
86
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"Increased cost due to back-fitting with a conventional wet tower
system is about 0.6 mills/KWH; however, site specific problems
can cause wide variations, both up and down, from this general value."
Finally, it is recognized that this report can not provide the expertise
required to evaluate crucial or particularly difficult cases, and in
such cases it is advisable for the reviewer to solicit outside help
from sources experienced in power plant economic evaluations.
87
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SECTION VIII
REFERENCES
1. U.S. Atomic Energy Commission. Preparation of Environmental
Reports for Nuclear Power Plants. Regulatory Guide 4.2.
Washington, D.C., March, 1973. 73 p.
2. Dynatech R/D Company. A Survey of Alternate Methods for Cooling
Condenser Discharge Water. Operating Characteristics and Design
Criteria. U.S. EPA Report No. 16130 DHS 08/70. August, 1970.
94 p. and System Selection, Design, and Optimization. U.S. EPA
Report No. 16130 DHS 01/71. January, 1971. 108 p. U.S. Government
Printing Office, Washington, D.C.
3. Hittman Associates, Inc. Nomographs for Thermal Pollution Control
Systems. U.S. EPA Report No. EPA-660/2-73-004. U.S. Government
Printing Office, Washington, D. C. 1973.
4. National Thermal Pollution Research Program and Great Lakes Regional
Office. Feasibility of Alternative Means of Cooling for Thermal
Power Plants Near Lake Michigan. U.S. FWQA. August 1970. (also
Supplement A. September 1970.)
5. Tichenor, B.A. Evaluating Thermal Pollution-Control Alternatives. -
In: Environmental Impact on Rivers, Shen, H.W. (ed.). Fort Collins,
Colorado, H. W. Shen, Publisher. 1973. p. 7-1 through 7-22.
6. Sonnichsen, J. C. Jr., B. W. Bentley, and G. F. Bailey. A Review
of Thermal Power Plant Intake Structure Designs and Related Environmental
Considerations. Hanford Engineering Development Laboratory, Report
No. HEDL - THE 73-24, UC - 12. May 1973. 77 p. & Appendix.
7. State of Washington Water Research Center. Analysis of Engineering
Alternatives for Environmental Protection from Thermal Discharges.
U.S. EPA Report No. EPA - R2 - 73 - 161. U.S. Government Printing
Office, Washington, D.C. March 1973. 228 p.
8. Entrainment and Intake Screening Workshop. The Johns Hopkins
University, Baltimore, Maryland. February 5-8, 1973. (Proceedings
In Press).
9. The Marley Company. Cooling Tower Fundamentals and Application
Principles. Kansas City, Missouri. 1967.
88
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1°' nsKevw'PLK\and ?• Br°°ke- The 'nutria! C°°^9 Tower.
tlsevier Publishing Company. 1959. 429 p.
11. Dynatech R/D Company. A Survey of Alternate Methods for Cooling
Condenser Discharge Water. Large-Scale Heat Rejection Equipment.
US. EPA Report No. 16130 DHS 07/69. U.S. Government Printing
Office, Washington, D.C. July 1969. 127 p.
12. Environmental Systems Corporation. Development and Demonstration
of Low-Level Drift Instrumentation. U.S. EPA Report No. 16130 GNK
iS(? r^'S> Gove™"ient Printing Office, Washington, D.C. October
iy/1. 56 p.
13. Sisson, W. Langelier Index Predicts Water's Carbonate Coating
Tendency. Power Engineering. 77_:44, February 1973.
14. E G & G, Inc. Potential Environmental Modifications Produced by
Large Evaporative Cooling Towers. U.S. EPA Report No. 16130 DNH
01/71. U.S. Government Printing Office, Washington, D.C. January
1971. 75 p.
15. Turner, B. D. Workbook of Atmosphere Dispersion Estimates. U.S. DREW,
Environmental Health Series, Cincinnati, Ohio. 1969. 84 p.
16. Hanna, S. R. Meteorological Effects of Cooling Tower Plumes.
(Presented at the Cooling Tower Institute Winter Meeting, Houston,
Texas. January 25, 1971.). 17 p. . ; ,. _
17. Hanna, S. R. Cooling Tower Plume Rise and Condensation. (Presented
at the Air Pollution Turbulence and Diffusion Symposium, Las Cruces,
New Mexico. December 7-10, 1971.) 6 p.
18. McVehil, G. E. Evaluation of Cooling Tower Effects at Zion Nuclear
Generating Station. Sierra Research Corporation Report No. TR - 0824.
Boulder, Colorado. October 30, 1970. 50 p. & Appendix.
••(
19. Colbaugh, W. C., J. P. Blackwell, and J. M.. Leavitt. Investigation
of Cooling Tower Plume Behavior. In: Cooling Towers, Chemical
Engineering Progress (eds.). New York,.American Institute of Chemical
Engineers, 1972. p. 83-86.
20. Stewart, R. E. Atmospheric Diffusion of Particulate Matter Released
from an Elevated Continuous Source. Journal of Applied Meteorology.
I (3):425-432, June 1968.
21. Hosier, C. L., J. Pena, and R. Pena. Determination of Salt Deposition
Rates from Drift from Evaporative Cooling Towers. Department of
Meteorology, The Pennsylvania State University. May 1972. 46 p.
89
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22. Roffman, A., et. al. The State of the Art of Salt Water Cooling
Towers for Steam Electric Generating Plants. Report No. WASH-1244,
UC-12 for U.S. AEC Contract No. AT (11-1) - 2221. Westinghouse
Electric Corporation, Pittsburgh, Pennsylvania. February 1973.
23. U.S. Atomic Energy Commission. Draft Environmental Statement
Related to the Forked River Nuclear Station, Unit 1, Jersey Central
Power and Light Company. Docket Number 50-363. Directorate of
Licensing, Washington, D.C. October 1972.
24. Edinger, J. E. and J. C. Geyer. Heat Exchange in the Environment.
Edison Electric Institute Research Project No. 49, EEI Publication
No. 65 - 902. New York, Edison Electric Institute, June 1, 1965.
259 p.
25. National Thermal Pollution Research Program. Industrial Waste Guide
on Thermal Pollution. U.S. FWPCA, Corvallis, Oregon, September
1968 (Revised). 112 p.
26. Brady, D. K., W. L. Graves, Jr., and J. C. Geyer. Surface Heat
Exchange at Power Plant Cooling Lakes. Edison Electric Institute
Research Project No. 49, EEI Publication No. 69-901. New York,
Edison Electric Institute, November 1969. 154 p.
27. Vanderbilt University. Effect of Geographical Location on Cooling
Pond Requirements and Performance. U.S. EPA Report No. 16130 FOQ
03/71. U.S. Government Printing Office, Washington, D.C. March
1971. 234 p.
28. Littleton Research and Engineering Corporation. An Engineering -
Economic Study of Cooling Pond Performance. U.S. EPA Report No..
16130 DFX 05/70. U.S. Government Printing Office, Washington, D.C.
May 1970. 172 p.
29. Tichenor, B. A. and A. G. Christiansen. Cooling Pond Temperature ,.,
versus Size and Water Loss. Proceedings of the American Society
of Civil Engineers, Journal of the Power Division. 97 (P03):589-596,
July 1971. ~
30. Sonnichsen, J. C., Jr., S. L. Engstrom, D. C. Kolesar, and G. C. Bailey.
Cooling Ponds—A Survey of the State of the Art. Hanford Engineering
Development Laboratory Report No. HEDL - TME 72 - 101. September
1972. 99 p. & Appendix.
31. Rossie, J. P. and E. A. Cecil. Research on Dry-Type Cooling Towers
for Thermal Electric Generation: Parts I and II. U.S. EPA Report
No. 16130 EES 11/70. U.S. Government Printing Office, Washington,
D.C. November 1970. 322 p. (Part I) and 101 p. (Part II).
90
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Plume Behav1°r ^d Potential
Gulf PHP A -r °f Ur§e Dry Cool1n9 Towers' RePO^ by
AT (04-3? 167 P^°TSy f°r U'St- Atomic Ener9y Commission Contract
fti IU4-3) - 167, Project Agreement No. 47. February 1973. 176 p.
33' lM16^^7L4-7H7:1Ma^rChD115?1913Hybn"d Wet/D^ C°o1^' Electrical World.
34. Olesen, K. A. And R. J. Budenholzer. Economics of Wet/Dry Cooling
Tower Show Promise. Electrical World. 178 (12):32-34, December
15, 1972.
35. Anon. Wet/Dry Cooling Towers .the Answer? Electrical World.
178 (6):80-83, September 15, 1972.
36. Anon. Wet/Dry Tower Shows Bright Promise. Power. 117:S-19,
March 1973.
37. Anon. The Latest in Towers: Fan-Assisted Cooling? Electrical World.
179 (1):32, January 1, 1973.
38. Sierra Research Corporation. Atmospheric Effects of Cooling Tower
Plumes, Northern States Power Company, Sherburne County Generating
Plant. Final Report for Black and Veatch Consulting Engineers.
March 15, 1971. 42 p.
38a. Silberman, E. and H. Stefan. Physical (Hydraulic) Modeling of Heat
Dispersion in Large Lakes. Argonne National Laboratory, Report No.
ANL/ES-2. August 17, 1970.
39. Shirazi, M. A. and L. R. Davis. Workbook of Thermal Plume Prediction,
Volume I, Submerged Discharge. U.S. EPA Report No. EPA - R2 -
72 - 005a. U.S. Government Printing Office, Washington, D.C.
August 1972. 228 p.
40. Jirka, G. and D. R. F. Harleman. The Mechanics of Submerged
Multiport Diffusers for Buoyant Discharges in Shallow water.
Massachusetts Institute of Technology, Ralph M. Parsons Laboratory,
Report No. 169. March 1973. 313 p.
41. Winiarski, L. and 0. Chasse. Plume Temperature Measurements of
Shallow, Submerged Model Discharges with Current. U.S. EPA Report
No. EPA-660/2-73-001 . Pacific Northwest Environmental Research
Laboratory, Corvallis, Oregon. 1973.
42. Policastro, A. J. and J. V. Tokar. Heated-Effluent Dispersion in
Large Lakes: State of the Art of Analytical Modeling, Part 1,
Critique of Model Formulations. Argonne National Laboratory,
Center for Environmental Studies, Report No. ANL/ES - 11. January
1972. 374 p.
91
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43. Stolzenbach, K. D., E. E. Adams, and D. R. F. Harleman. A User's
Manual for Three-Dimensional Heated Surface Discharge Computations.
U.S. EPA Report No. EPA - R2 - 73 - 133. U.S. Government Printing
Office, Washington, D.C. January 1973. 97 p.
44. Shirazi, M. A. A Critical Review of Laboratory and Some Field
Experimental Data on Surface Jet Discharge of Heated Water. U.S.
EPA, Pacific Northwest Environmental Research Laboratory, Con/all is,
Oregon. PNERL Working Paper No. 4. March 1973. 46 p.
45. Brungs, W. A. Effects of Residual Chlorine on Aquatic Life:
Literature Review. U.S. EPA, National Water Quality Laboratory, v
Duluth, Minnesota. 1973. ,^
46. Nelson, 6. R. Predicting and Controlling Residual Chlorine in Cooling,
Tower Blowdown. U.S. EPA, Pacific Northwest Environmental Research
Laboratory, Corvallis, Oregon. PNERL Working Paper No. 9, April
1973. 49 p.
47. Jimeson, R. M. and G. G. Adkins. Factors in Waste Heat Disposal
Associated with Power Generation. (Presented at American Institute
of Chemical Engineers', 68th National Meeting. Houston, Texas.
February 28 - March 4, 1971.)
48. Parkhurst, J. D., L. A. Haug, and M. L. Whitt. Ocean Outfall Design
for Economy of Construction. Journal of the Water Pollution Control
Federation. 39_:987-993, June 1967.
49. Anon. Engineering News Record. 185 (12), September 17, 1970.
50. Kempf, F. J. and J. F. Fletcher. Effects of Site Location on Capital
Costs of Nuclear Electric Plants. Battelle Northwest Laboratory,
Rich!and, Washington. March 1969.
51. Woodson, R. D. Cooling Towers for Large Steam - Electric Generating
Units. In: Electric Power and Thermal Discharges, Eisenbud, Merril,
and Gleason (eds.). New York, Gordon and Breach Publishers, 1970.
p. 351-380.
52. Hauser, L. G. Cooling Water Sources for Power Generation. (Presented
at American Society of Civil Engineers, National Water Resources
Engineering Meeting. Memphis, Tennessee. January 26-30, 1970).
Preprint No. 1102.
53. Swengel, F. M. A New Era of Power Supply Economics. Power Engineering.
7_4:30-38, March 1970.
92
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54. Anderson, R. T. Simplify Power-Plant Cost Calculations. Power.
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Concerning Thermal Discharges into Lake Michigan. For the U.S. EPA,
Region V, Enforcement Division, Contract Report No. 72-1. August 1972.
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93
*US. GOVERNMENT PRINTING OFFICE:1973 546-313/184 1-3
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Plant *^ew™9 Environmental Impact Statements - Power
Plant Cooling Systems, Engineering Aspects
> A"G" Rainwater' F'H" Shlrazl, M.A.,
-fora:,:. - Org^
"
National Thermal Pollution Research Program
Pacific Northwest Environmental Research Laboratory
EPA, NERC-Corvallis, Oregon
:tiOB „Environmental Protection'A§ency@
Environmental Protection Agency report number
EPA-660/2-73-016, October 1973.
Repc Ho.
Pr 3/ect ftf o
Contrast/Grant o
Typ. ' Rep; snd S'rw
«?•«
•.^ z
This report describes the approach and technical base that have been used by EPA's
National Thermal Pollution Research Program for reviewing those portions of
Environmental Impact Statements (EIS's) relative to the engineering aspects (including
economics) of cooling water systems for thermal power plants. The report provides
techniques and data to enable the EIS reviewer to make sound judgements concerning
the adequacy of both the cooling water system selected for the power plant and the
EIS comments on that system. Literature citations are provided to direct the reviewer
to additional and more detailed information.
The report provides information and discussions on cooling system configurations,
operation, environmental effects, and costs. Consideration is given to the intake
as well as the discharge.
Various closed-cycle cooling systems employing cooling towers, cooling ponds, spray
systems, and other devices are covered. Methods of assessing alternative selections
and benefit-cost analyses are presented. Non-thermal aspects of cooling water
systems are discussed.
The report lays the groundwork for a technically sound EIS review; however, the reviewe
must supplement the material presented herein with references and perhaps technical
consultation to prepare compr°hon?i''Y0 anH HotaiiaH rowiaui
J7a. jjescriptors
Thermal power plants*, Nuclear power plants*, Environmental effects*, Electric
power, cost-benefit analysis, cooling towers, thermal pollution
17 b. Identifiers
Environmental Impact statements*, Cooling water systems*
11:.. CO WRR Field & Group Q66, 05B, 06B
19.
-MyC.
21, Vo. of
, Pages
''&;*» <
Send To:
WATER RESOURCES SCIENTIFIC INFORMATION CENTER
US DEPARTMENT OF THE INTERIOR
WASHINGTON. D C. 2O24O
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