NC0024392_Part 1 Condition (A) (22)_20190826

st, DUKE Duke Energy
McGuire Nuclear Station
ENERGY: 12700 Hagers Ferry Road
Huntersville,NC 28078
Certified Mail: 7016 0910 0001 0230 4202
August 26, 2019
Ms. Linda Culpepper, Director
North Carolina Department of Environmental Quality RECEIVED/NCDEQ/DWI
Division of Water Resources
512 N. Salisbury Street AUG 2 9 2019
Raleigh, NC 27604
Water Quality
Subject: Duke Energy Carolinas LLC/McGuire Nuclear Station Permitting Section
Renewal Application for NPDES Permit No. NC 0024392
Part 1 Condition (A)(22) - Clean Water Act Section 316(b) Reports
Mecklenburg County
Dear Ms. Culpepper:
Duke Energy Carolinas LLC (Duke Energy) McGuire Nuclear Station (MNS) has
prepared this summary of the reports required to be submitted per the 316(b) Rule and
NPDES Permit No. NC0024392. The reports provide detailed information which should
enable the Director to make a Best Technology Available (BTA) entrainment
determination after considering the site-specific factors and other information. Although
the impingement compliance preference is also presented in these reports, final selection
is dependent upon the BTA entrainment decision. The enclosed reports provide our
evaluation of the MNS cooling water intake structure with consideration of the facility,
source waterbody, and potentially feasible compliance measures. Duke Energy
respectfully requests that the Director concur with our proposed impingement and
entrainment compliance measures to establish BTA at the MNS.
Following is a summary of the enclosed 316(b) reports to facilitate the NC DEQ DWR's
review.
Existing Facility 316(b) Rule Summary
The USEPA published the Clean Water Act 316(b) Rule for existing facilities with an
effective date of October 14, 2014. Although there are exceptions, generally the Rule
requires that a NPDES permittee with a cooling water intake structure (CWIS) design
capacity of 2 MGD or greater to submit the following reports based on the CWIS average
(actual) flow:
• <125 MGD—40 CFR § 122.21(r)(2)-(8) reports
• >125 MGD—40 CFR § 122.21(r)(2)-(13) reports
• New unit at an existing facility—40 CFR § 122.21(r)(2)-(8) and (14) reports
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Based on the NPDES Permit Director review of these reports, a site-specific entrainment
decision is made to establish BTA and then the permittee selects the appropriate
complementary impingement compliance alternative(s).
The MNS CWIS ("Main Intake") has a design capacity greater than 2 MGD and an
average intake flow of greater than 125 MGD. Therefore the 40 CFR § 122.21(r)(2)-(13)
reports are enclosed with this submittal.
MNS Cooling Water Intake Structure Summary
The MNS consists of two identical pressurized water nuclear reactors, each with a net
electrical generation of approximately 1,158 MW. Unit 1 began commercial operation
during 1981 with Unit 2 following in 1984. The MNS carbon free generation is critical
for meeting Duke Energy customer needs.
MNS has two separate CWIS to provide cooling water for various plant purposes,
including the steam turbine condensers and nuclear safety-related systems. The Main
Intake is a shoreline structure located in a small cove near Cowans Ford Dam on Lake
Norman. The Main Intake bay center is approximately 30 feet below the lake pool
elevation. The Low Level Intake (LLI) is located near the base of Cowans Ford Dam and
withdraws water from Lake Norman with the center of the structure approximately 100
feet below the pool elevation. Sections 2, 3, and 5 of the enclosed reports provide a
comprehensive description of the MNS CWIS. The following table provides a summary
of the major characteristics for each CWIS:
Main Intake Low Level Intake(LLI)
Nuclear safety related("RN
Purpose Once through cooling water system")service water.
and other plant requirements
(Note 1)
Invert Elevation (ft msl) 715 644
Depth (from full pond elevation) 45 116
(feet)
Depth of Water Withdrawal (ft 715 745 654-670
msl)
Structure linear length (feet) 247 118
Number of Intake Bays 8 (4 per unit) 3
16traveling t ave water screens
Number of Screens and Type g9 fixed panel screens
(8 per unit)
Screen Mesh (inches) 3/8 3/4
Through-screen velocity (fps) 1.2 0.06
Number of Pumps 8 (4 per unit) 4 (note 2 & 3)
Pump Rating(gpm) 254,000 17,500
Total Design Flow (MGD) 2,969 43.2
Average Flow(MGD) 2,631 27.0
Note 1: LLI is also the routine makeup water source to the safety-related Standby Nuclear Service
Water Pond.
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Note 2: There are four RN pumps with 17.500 gpm capacity each;however only two are typically
operated with two for redundancy.
Note 3: There are also 3 pumps with 150,000 gpm capacity each with one or two pumps operating
intermittently for once to five weeks per year as dictated by plant operations for MNS thermal
discharge limitation compliance.
The area of influence (AOI) for impingement is defined as the area encompassed by the
0.5 fps velocity contour at the intake structure. For the Main Intake, using the theoretical
design flow of 2,969 MGD and the Lake Norman authorized maximum (non-emergency)
drawdown water elevation of 751 ft msl (which is nine feet below normal pool elevation
of 760 ft msl), the estimated AOI extends 80 feet from the CWIS and encompasses an
area of 0.68 acres. Section 2.3 of the report provides information used to conservatively
estimate the AOI.
CWIS Source Water Summary
The MNS source waterbody, Lake Norman, was expressly created to provide cooling
water for electrical generation facilities including MNS and to power generators at the
Cowans Ford Hydroelectric Station. As part of the Catawba-Wateree Hydroelectric
Project (FERC No. 2232), Lake Norman is subject to licensing by the Federal Energy
Regulatory Commission (FERC). Lake Norman is an impoundment on the mainstem
Catawba River and is bracketed upstream by Lookout Shoals Lake and downstream by
Mountain Island Lake.
Lake Norman is characterized as an "inland sea" with 538 miles of shoreline, a surface
area of more than 32,475 acres, and an impounded volume of nearly 1,100,000 acre-feet.
Lake Norman supports a balanced fishery, provides recreational opportunities, and is
aesthetically desirable. Water quality, including fishery information, is well documented
at Lake Norman. Routine source waterbody assessments have occurred prior to and after
MNS operations and currently continue. The Lake Norman fishery studies have included
electrofishing, purse seine sampling, hydroacoustic surveys, and creel surveys. None of
these studies have attributed any adverse impact to operation of MNS including the
cooling water intake structure.
The North Carolina Wildlife Resources Commission (NCWRC) manages Lake Norman
through periodic fish stocking programs and assessments. The Lake Norman fish
population is diverse and many species were artificially introduced by the NCWRC
and/or the public. An established forage fishery exists to support important recreational
sportfishing species such as catfish black bass, and temperate bass. Much of the forage
base consists of shad and alewife, which are considered by the Rule to be a fragile
species.
As presented in Sections 2, 4, 7, 9, and 11 of the enclosed reports, there are no threatened
or endangered species that could be impacted by the MNS CWIS. Two years of
impingement and entrainment field data was collected at the Main Intake with discrete
24-hour samples occurring at one week intervals for impingement and two week intervals
for entrainment. The following tables provides a summary of these two sampling efforts:
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MNS Main Intake Impingement
2017 Flows— 2016-2017 Average
2016 Flows—Estimated
Annual Impingement Estimated Annual Estimated Annual
Impingement Impingement(Note 1)
Threadfin Shad 890 886 888
Alewife 336 313 324
Gizzard Shad 56 53 54
Bluegill 143 138 140
White Bass 77 75 76
Striped Bass 77 72 74
Channel Catfish 63 60 62
Unidentified Fish 54 54 54
Others 479 462 470
Total Fragile 1,295 1,263 1,279
Total Non-Fragile 880 850 865
Note 1 — crage annual impingement represents simple arithmetic average between 2016 and 2017.
MNS Main Intake Entrainment
2016 Flows—Estimated 2017 Flows— 2016-2017 Average
Annual Entrainment Estimated Annual Estimated Annual
Entrainment Entrainment(Note 1)
Shad and Herring Family 114,497,612 299,678,462 207,088,037
Shad Species 69,574,216 3,985,796 36,780,006
Sunfish Species 10,141,792 2,363,843 6,252,818
White Perch 7,836,624 61,829,106 34,832,865
Unidentified Fish 6,620,757 948,137 3,784,447
Alewife 4,445,066 3,169,191 3,807,128
Gizzard Shad 3,826,455 683,839 2,255,147
Threadfin Shad 1,998,006 999,003
Others(Note 2) 5,453,780 2,063,051 3,758,416
Total Fragile 194,341,355 307,517,288 250,929,322
Total Non-Fragile 30,052,953 67,204,137 48,628,545
Note 1 —Average annual entrainment represents simple arithmetic average between 2016 and 2017.
Note 2—The anomalous collection of Inland Silverside in 2016 is not included in the 2016 data presented.
Fragile species comprised approximately 60% of the estimated impingement and 84% of
the estimated entrainment at the MNS Main Intake. Section 11 of the enclosed report
presents an evaluation of the entrainment impacts using models such as Equivalent
Adults (EA) and Production Foregone (PF) which account for the natural survival of each
organism, trophic transfer, and its potential to become an adult that could be of benefit to
the Lake Norman aquatic system or provide a recreational opportunity. Based on the EA
and PF modeling, the monetary value of the MNS entrainment on an annual basis ranges
from $818 to $24,168.
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Impingement and Entrainment Compliance
The 316(b) Rule requires the hypothetical evaluation of a closed-cooling and fine mesh
screen retrofit. The closed cycle cooling retrofit was evaluated using mechanical draft
cooling towers (MCDT). The fine mesh screen retrofit was evaluated using 2.0 mm fine
mesh "fish friendly" traveling screens (FMS). Section 10 of the enclosed report provides
the engineering evaluation, including costs, for the MCDT and FMS scenarios. It should
be noted that a closed cycle cooling retrofit at an existing facility presents many
challenges which may not he fully defined in the presented evaluation. Although fine
mesh screens are less challenging to retrofit, there could be unforeseen issues that are not
incorporated in the presented evaluation.
Sections 11 and 12 of the report presents the benefits and costs of each technology,
including the currently configured CWIS. Conversion to closed cycle cooling at
McGuire would result in the loss of winter fishing opportunities and commensurate local
economic impacts at Lake Norman. The following table (Table 11-17 in the report) and
figure (Figure 1 1-1 1 in the report) summarizes the net benefits of each evaluated
technology:
Regulatory Social Benefits
Standard Technology Total Social Net
Addressed Costa Impingement Entrainment Total Benefits
Benefits Benefits Benefits
Impingement De Minimis $457 $0 $0 $0 -$457
Impingement 2.0-mm FMS $51.2M $457 $0.5M $0.5M -$50.7M
and Closed-Cycle
Entrainment Retrofit $1.47B $397 $0.3M $0.3M -$1.47B
Note: "M" = million. "B' =billion
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Legend
Total Social Costs and Total Total
Benefits($) Social—► 4— Social
$1 500P.1 Benefit Cost 51.47E
Net Benefits i
(Benefits minus Costs)
Impingement
Compliance Entrainment Compliance Alternatives
Option
51 000M
1
$51.2M
S50M
5
50.5M
0.5M
SO.3M"
$500 5457
$0 ry .
-$500 -5457
De Minimis
-SSOM §125.94(c)(11)
-S50 7\I
2.0-mm Fine-Mesh
Screens
-$1,000M •
-S1 500M -
-S 473
Net Benefits($) Mechanical Draft
(Benefits minus Costs) Cooling Towers
Notes Social benefits are estimated using the 2016 entrainment data to present the benefits
associated with the highest obseried entrainment. Social costs and social benefits V E R I T A S
are discounted at 3°0
The'offal benefits for cooling towers are less than the total benefits for fine-mesh screens Economic Consulting
because fine mesh screens will be in operation longer
The "Total Social Cost" in the above table and figure demonstrates that the difference
between the costs and benefits is negative for each potential scenario. However, the
existing McGuire CWIS configuration ("De Minims") has a markedly smaller impact
than the other two technologies. The 316(b) Rule at 40 CFR § 125.98(0(4) states that the
Director can determine that no additional controls are necessary beyond the currently
installed technologies and implemented measures where costs are substantially
disproportionate and do not justify the social benefits or result in unacceptable adverse
impacts that cannot be mitigated. This is exactly the case for the MNS CWIS, and
therefore Duke Energy respectfully requests the Department concur with our analysis that
no additional controls are required to establish BTA with consideration of the following:
• Lake Norman is a managed waterbody
• MNS has no impact on any threatened or endangered species
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• Impingement rates are very low (many days would likely have no reasonably
anticipated impingement)
• Entrainment is mostly associated with prolific, reproducing forage fish considered
by the EPA to be fragile species
• The costs to install any technology are wholly disproportionate to any benefit
• Numerous prior studies have confirmed that the MNS CWIS has no impact on the
Lake Norman aquatic community
The estimated $1,850,000,000 compliance cost for a MDCT retrofit results in an
approximate 75,000:1 cost to benefit ratio. MDCT and FMS are unjustified based on the
above factors and therefore the existing CWIS should be considered as BTA per the
316(b) Rule.
Duke Energy will be contacting NC DEQ DWR staff in the near future to request a
meeting to provide an overview of these documents. Should you have any questions
concerning this 316(b) submittal in the interim, please contact Mr. John Ballard, MNS
Site Environmental Field Support, by phone at 704-875-5227, or via e-mail at
[e-mail]. Specific 316(b) technical aspects can be addressed by
Mr. Michael Smallwood at 704-875-5227 or via email at Michael.Smallwood@duke-
eneNy.com.
I certify, under penalty of law, that this document and all attachments were prepared
under my direction or supervision in accordance with a system designed to assure that
qualified personnel properly gather and evaluate the information submitted. Based on
my inquiry of the person or persons who manage the system, or those persons directly
responsible for gathering the information, the information submitted is, to the best of my
knowledge and belief, true, accurate, and complete. I am aware that there are significant
penalties for submitting false information, including the possibility of fines and imprisonment
for knowing violations.
Sincerely,
Thomas D. Ray
Site Vice President
Duke Energy Carolinas LLC
McGuire Nuclear Station
Enclosures
cc: Ms. Julie Grzyb, NPDES Complex Permitting Unit
Mr. Corey Basinger, Mooresville Regional Office
Mr. John Ballard, Duke Energy MNS Site Environmental Field Support
Mr. Don Safrit, Duke Energy Carolinas Permitting & Compliance
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