Document ID: EPA-HQ-OW-2008-0667-0014
Agency: epa
Document Type: Supporting & Related Material
Title: 
Posted Date: 2009-11-05T05:00Z

Site Visit Report

	St. Lucie Plant

	6501 South State Rd

	Jensen Beach, FL 34957

March 26, 2008

Background and Objectives

The Environmental Protection Agency (EPA) is in the process of
developing 316(b) cooling water intake structure requirements that
reflect the best technology available (BTA) for minimizing adverse
environmental impact for all existing power plants and manufacturing
facilities. As part of this process, EPA staff is visiting electric
generators and manufacturers to better understand the cooling water
intake structure (CWIS) technologies in use at facilities, including the
site-specific characteristics of each facility and how these affect the
selection and performance of CWIS technologies.  EPA is also visiting
facilities to better understand cooling water use and specific issues or
technologies that can affect 316(b) compliance.  St. Lucie Plant (St.
Lucie) was selected for a site visit due to its use of an offshore
intake location (with a velocity cap) and its large intake flows.

Facility Description

St. Lucie is located on Hutchinson Island, a barrier island on the
eastern coast of Florida.  The facility, owned by Florida Power and
Light (FPL) and located on a 1132 acre site, withdraws from an offshore
intake in the Atlantic Ocean and began operations in 1976.  St.
Lucie’s discharge point is also an oceanic offshore discharge.

The facility’s NPDES permit (FL0002208) expires in 2010.

Electricity Generation and Transmission

St. Lucie has two nuclear generating units capable of generating a total
of 863 megawatts.  The facility typically has a capacity utilization
rate of over 90%, but has been below that threshold (approximately 85%)
in recent years due to extended outages to replace the reactor head and
the pressurizer, as well as repairs due to recent hurricanes and other
large storms.  Typical outages are every 18 months (per unit) in the
spring or fall and last 20 to 30 days.

FPL also owns the switchyard and transmission facilities.

Cooling Water Intake Structure

St. Lucie withdraws cooling water from three velocity caps located 1200
feet offshore at a depth of 24 feet.  The facility noted it selected
mid-depth intakes to avoid bottom dwelling fish.  The velocity caps each
consist of cement slabs on 16 pillars that are 9 inches in diameter. 
The velocity caps are unscreened and direct water into a 1 mile long
intake canal.  At the entrance of the canal, a series of two barrier
nets trap larger fish and sea turtles; smaller nets and traps are used
to transport these organisms back to the ocean.,, Adjacent to the
facility at the end of the canal, two shoreline CWISs provide cooling
water directly to each of the generating units.  These traveling screens
are standard 3/8” mesh with no fish return (materials on the screen
are disposed of in a landfill).

The permitted design intake flow for the facility is 1477 million
gallons per day (MGD).

In the original site plans, the intake structure was to be located on
the western side of the facility’s canal and draw water from the
Indian River.  However, during construction, concerns arose about the
biological productivity in the estuary and the current offshore location
was selected as the best location for the intake structure.  Biological
sampling was conducted to compare the ocean and the estuarine
environments.  An intake structure on the Indian River remains as the
source of emergency cooling water should the offshore CWIS fail.

The facility uses both mechanical (Tapprogge) and chemical (chlorine
injection) approaches to address biofouling concerns.

Impingement and Entrainment Information

St. Lucie conducted seven years of biological monitoring in the late
1970s and early 1980s.  Additionally, the facility recently completed
another 21 months of monitoring that compared the ocean and estuarine
environments through parallel sampling events to demonstrate the
effective reduction in impingement and entrainment realized by utilizing
an offshore intake location.  During its recent sampling, St. Lucie
collected fish samples with gill nets every other week at three
locations in the Atlantic Ocean:  close to shore, close to the intake
structure, and off-shore and in the estuary.  Additionally, St. Lucie
collected entrainment data (day and night) with a 300-micron plankton
net located at mid depth where the intake pipe comes into the canal.    

St. Lucie indicated that its earlier studies indicated a higher
abundance of impingeable-sized fish near the shore as opposed to
off-shore.  Also, ichthyoplankton densities were 58% to 73% lower at
mid-depth than near the water surface.  Near shore densities
approximated 2.5 fish/100 m3 and decreased with distance off-shore. 
Densities beyond the cap approximated 0.8 fish/100 m3.  

St. Lucie also provided some results from the first year (2006) of the
recent sampling in regards to reductions in densities between the Indian
River Lagoon and the Atlantic Ocean.  In addition to the reductions
indicated below, the facility noted a 94% reduction in biomass between
the ocean and the estuary.

	I Reductions	E Reductions

Total	77.1%	89.7%

Fish only	71.6%	78.4%

Shellfish only	98.5%	90.4%

Facility representatives stated that they expected to be in compliance
with the now-suspended Phase II rule.  Due to the offshore intake
location, the facility planned to document significant entrainment
reductions.  With an improved barrier net and capture program in the
canal, the facility expected to be able to meet the impingement
requirements.  Facility representatives stated that they rarely see
impinged fish in the screenwash. 

Cooling Tower Feasibility

Facility representatives estimated that conversion to a closed-cycle
cooling system would require an 80 cell mechanical draft cooling tower
or two large natural draft towers. St. Lucie noted it has once-through
condensers, affecting the design of cooling towers.  The facility noted
that towers would be a challenge because of the typically high wet bulb
temperature.  Facility representatives estimate an additional 20%
premium in the total cost to make the towers “hurricane-resistant.” 
They also noted that a mangrove forest to the south is likely the best
potential site for cooling towers, but would require removing the
forest; in addition, ambient winds would carry the salt drift back to
the plant, leading to potential mechanical problems.  The facility also
noted local resistance may be an issue due to its proximity to the beach
and local resistance to a recent windmill power generation project.

The facility is often requested to operate in the winter to provide
thermal effluent-warmed waters as manatee habitat; facility
representatives noted that converting to a closed-cycle system would
remove this thermal effluent and may eliminate the manatee habitat.

Additional Information

The source water generally maintains a constant salinity and
temperature.

The state of Florida and other groups have approached the facility about
co-locating a desalinization facility at St. Lucie.  To date, St. Lucie
has opted against the proposal, as the possibility that cooling towers
could be required for 316(b) compliance, thereby negating the advantages
for co-locating a desalinization plant.

A municipal water treatment plant has a discharge pipe that empties into
St. Lucie’s discharge canal.  The outfall rarely discharges, however,
and facility representatives stated that there haven’t been any
problems with this discharge in at least 10 years.

St. Lucie expressed an interest in receiving credit for impingement and
entrainment reductions for locating its intake on the ocean rather than
on the estuary.  Facility representatives stated that they are given
impingement and entrainment “credit” for reducing or halting
operations during peak spawning periods.

Facility representatives also noted some areas for possible
clarification in the revised 316(b) rules: (1) if the organisms are
entrained, then they are not impinged, and double counting should not
occur; (2) in some cases, an organism is neither impinged nor entrained,
but could be realistically be considered “entrapped.”

Facility representatives also discussed a nearby plant (Riviera),
particularly with regard to the difficulties that would be encountered
in converting the facility to closed-cycle cooling.  The Riviera plant
has 4 units with a submerged shoreline intake.  The facility’s intake
structure is located on property owned by the port authority, and the
site is bounded by the port, highways, and residential areas. 
Riviera’s thermal discharge is also an integral part of a manatee
protection plan, as the area near the outfall has now been designated
critical habitat.  Facility representatives estimated that the cost to
convert to closed-cycle would be approximately $300 million and likely
lead to the closure of the facility.  Due to a lack of available
freshwater, saltwater towers would be required.  Additionally, the
uncertainty regarding cooling towers is delaying a potential repowering
project.

Attachments

Attachment A		List of Attendees

Attachment B		Aerial Photo

Attachment C		Manatee Photos

Attachment A--List of Attendees

Paul Shriner, EPA

Jan Matuszko, EPA

Kelly Meadows, Tetra Tech

Ron Hix, FP&L

Vince Munne, FP&L

David Nepshe, FP&L

Attachment B—Aerial Photo

Please see DCN 10-6515D accompanying this document.

Attachment C—Manatee Photos

Please see DCNs 10-6515A-C accompanying this document.

 The discharge uses 57 diffuser ports to mitigate thermal impacts.

 Unit 1 began operation in 1976, Unit 2 in 1983.  The facility is
planning an uprating project (via enriched fuel and an upgraded
turbine/condenser) in 2012 that will add another 206 megawatts of
generating capacity.  The intake flow will remain the same.

 Originally, two velocity caps (each 12 feet in diameter) served the
facility; a third (16 foot diameter) was later added.  Each velocity cap
has a dedicated pipe that transports water to the intake canal.  The
three caps are located side by side.

 The bottom of the velocity cap is approximately 7 feet from the ocean
bottom and the top of the velocity cap is approximately 5 feet
underwater at low tide.

 There are no pumps to withdraw water into the 300 feet wide, 25 foot
deep canal—the system is passively fed by the pumps at the shoreline
intake structure within the canal.  The canal is dredged on an
infrequent basis.

 The first barrier net (mesh size of 5”) is approximately 600 feet
from the point where the water from the velocity cap enters the canal. 
The facility is currently building a new net system that will be easier
to maintain.  The second net (mesh size of 10”) is located in the
western portion of the canal. 

 St. Lucie’s NPDES permit limits the number of turtles they can entrap
within the intake canal annually to 1000 turtles (for every 100 turtles
they are allowed one injured or dead), based on recommendations from the
National Marine Fisheries Service.  The facility employs four full-time
biologists to monitor the canal for entrapped turtles, record biological
data about the individuals, and to quickly return them to the ocean. 
St. Lucie’s data collection has resulted in one of the largest turtle
biological databases in the world.  In recent years, the number of
turtles has approached the permit limit; the facility is currently
examining options for exclusion devices at the offshore intake.

 The facility also occasionally uses net traps to capture fish and
return them to the ocean, but many fish remain in the upper portion of
the canal, surviving on smaller entrapped fish.  Approximately 10,000
pounds of fish were returned to the ocean last year.  Aquariums also use
the canal as a collection site for marine organisms, due to the
convenience.

 The collected sample was transferred to jar for subsequent
identification, counting, and biomass determination.  The facility
counted fish/shellfish, eggs, larvae, and juveniles, which were
identified to the lowest taxonomic level possible.  The facility noted
that the majority of the costs associated with this effort were for QA. 

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