Text

2024 Annual Radioactive Effluent Release Report
	ML25122A018
Person / Time
Site:	Seabrook
Issue date:	05/01/2025
From:	Mack K; NextEra Energy Seabrook
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	L-2025-096
	Download: ML25122A018 (1)
	v • d • e

NEXTeraM ENERGY.

SEABROOK U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 Re:

Seabrook Station Docket No. 50-443 Renewed Facility Operating License NPF-86 2024 Annual Radioactive Effluent Release Report May 1, 2025 L-2025-096 1 O CFR 50.36a Pursuant to 10 CPR 50.36a and Technical Specification 6.8.1.4, NextEra Energy Seabrook, LLC submits the Annual Radioactive Effluent Release Report for 2024. A copy of the Offsite Dose Calculation Manual (ODCM) is not attached, as there were no changes for this annual period.

The following information is provided in the enclosures: : Effluent Release data as required by Regulatory Guide 1.21 : Radiation dose assessment : Joint frequency distributions of wind speed, wind direction, and atmospheric stability Should you have any questions regarding this submission, please contact Maribel Valdez, Fleet Licensing Manager, at 561-904-5164.

Sincerely, K~~XlJ Director, Licensing and Regulatory Compliance, 2 and 3 cc:

USNRC Regional Administrator, Region I USNRC Project Manager, Seabrook Station Nuclear Plant USNRC Senior Resident Inspector, Seabrook Station Nuclear Plant USNRC Regional Inspector, Region I, N. Eckhoff American Nuclear Insurers, Dylan Freiermuth NextEra Energy Seabrook, LLC P.O. Box 300, Lafayette Road, NH 03874 Effluent Release Data as Required by Regulatory Guide 1.21

EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT Supplemental Information 2024 Facility:

Seabrook Station Unit 1 Licensee: NextEra Energy Seabrook, LLC 1.

Regulatory Limits A.

Gaseous Effluents a.

5.0 mrad per quarter gamma air dose.

b.

10.0 mrad per quarter beta air dose.

c.

7.5 mrem per quarter to any organ.

B.

Liquid Effluents a.

1.5 mrem per quarter total body.

b.

5.0 mrem per quarter any organ.

c.

2.0 E-04 µCi/ml dissolved or entrained gas.

2.

Effluent Concentration Limits Provide the ECLs used in determining allowable release rates or concentrations.

a.

Fission and activation gases: 10 ECL b.

Iodines: 10 ECL c.

Particulates, half-lives >8 days: 10 ECL d.

Liquid Effluents: 10 ECL 3.

Average Energy Not applicable 4.

Measurements and Approximations of Total Radioactivity Provide the methods used to measure or approximate the total radioactivity in effluents and the methods used to determine radionuclide composition.

A.

Fission and activation gases: Determined by gamma spectroscopy. Total error is based on stack flow error, analytical error, and calculated sampling error.

B.

Iodines: Determined by collection on charcoal with subsequent gamma spectroscopy analysis. Total error is based on stack flow error, analytical error, and calculated sampling error.

C.

Particulates: Determined by collection on fixed filter with subsequent gamma spectroscopy analysis. Strontium is determined by composite analysis of filters by liquid scintillation, gross alpha by proportional counter and iron 55 by liquid scintillation. Total error is based on stack flow error, analytical error, and calculated sampling error.

D.

Liquid Effluents: Determined by gamma spectroscopy. A composite sample is analyzed for strontium by liquid scintillation, tritium by liquid scintillation, gross alpha by proportional counter and iron 55 by liquid scintillation. Total error is based on the volume discharge error and analytical error.

E.

ND: None Detected or No Detectable Activity

5. Batch Releases Provide the following information relating to batch releases of radioactive materials in liquid and gaseous effluents.

A.

Liquid

a.

Number of batch releases: 93

b.

Total time for batch releases: 21096 minutes

c.

Maximum time period for batch release: 1089 minutes

d.

Average time period for batch release: 227 minutes

e.

Minimum time period for batch release: 17 minutes

f.

Average stream flow during periods of release of effluents into a flowing stream: 1.60 E+06 liters per minute B.

Gaseous

a.

Number of batch releases: 19

b.

Total time for batch releases: 33297 minutes

c.

Maximum time period for batch release: 16881 minutes

d.

Average time period for batch release: 1842 minutes

e.

Minimum time period for batch release: 4 minutes

6.

Abnormal Releases A.

Liquid

a.

Number of releases: 0

b.

Total activity released: N/A B.

Gaseous

a.

Number of releases: 0

b.

Total activity released: N/A

TABLE 1A EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 GASEOUS EFFLUENTS-SUMMATION OF ALL RELEASES Unit Quarter 1

Quarter 2

Quarter 3

Quarter 4

Est. Total Error, %

A. Fission and activation gases

1. Total releases Ci 8.41E-03 2.80E-01 1.07E-02 1.31E+00 1.70E+01

2. Average release rate for period uCi/sec 1.07E-03 3.56E-02 1.35E-03 1.65E-01

3. Percent of applicable Technical Specification limit 8.32E-05 3.48E-03 1.10E-04 1.52E-02 B. Iodines

1. Total release Ci ND ND 8.17E-07 3.68E-06 1.50E+01

2. Average release rate for period uCi/sec N/A N/A 1.03E-07 4.63E-07

3. Percent of applicable Technical Specification limit N/A N/A 1.81E-01 4.09E-01 C. Particulates

1. Total release Ci 2.05E+00 5.02E+00 3.13E+00 1.86E+00 1.80E+01

2. Average release rate for period uCi/sec 2.61E-01 6.38E-01 3.94E-01 2.34E-01

3. Percent of applicable Technical Specification limit 1.61E-01 1.40E-01 1.81E-01 4.09E-01

4. Total alpha radioactivity Ci ND ND ND ND D. Tritium

1. Total release Ci 1.13E+01 9.37E+00 1.30E+01 2.78E+01 1.60E+01

2. Average release rate for period uCi/sec 1.44E+00 1.19E+00 1.64E+00 3.50E+00

3. Percent of applicable Technical Specification limit 1.61E-01 1.40E-01 1.81E-01 4.09E-01

TABLE 1B EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 GASEOUS EFFLUENTS-ELEVATED RELEASES BATCH Nuclides Released Unit Quarter 1

Quarter 2

Quarter 3

Quarter 4

1. Fission and activation gases argon-41 Ci 7.77E-03 2.78E-01 1.03E-02 1.31E+00 krypton-85 Ci ND ND ND ND krypton-85m Ci ND 1.58E-04 ND ND krypton-87 Ci ND ND ND ND krypton-88 Ci ND ND ND ND xenon-131m Ci ND 1.34E-03 ND ND xenon-133 Ci ND ND ND ND xenon-133m Ci ND ND ND ND xenon-135 Ci 6.39E-04 7.73E-04 3.18E-04 8.41E-05 xenon-135m Ci ND ND 8.57E-05 ND xenon-138 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 8.41E-03 2.80E-01 1.07E-02 1.31E+00

2. Iodines iodine-131 Ci ND ND ND ND iodine-132 Ci ND ND ND ND iodine-133 Ci ND ND ND ND iodine-135 Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

3. Particulates strontium-89 Ci ND ND ND ND strontium-90 Ci ND ND ND ND cesium-134 Ci ND ND ND ND cesium-137 Ci ND ND ND ND barium-lanthanum-140 Ci ND ND ND ND cobalt-58 Ci ND ND ND ND cobalt-60 Ci ND ND ND ND chromium-51 Ci ND ND ND ND manganese-54 Ci ND ND ND ND niobium-95 Ci ND ND ND ND iron-59 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

TABLE 1B EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 GASEOUS EFFLUENTS-ELEVATED RELEASES CONTINUOUS Nuclides Released Unit Quarter 1

Quarter 2

Quarter 3

Quarter 4

1. Fission and activation gases argon-41 Ci ND ND ND ND krypton-85 Ci ND ND ND ND krypton-85m Ci ND ND ND ND krypton-87 Ci ND ND ND ND krypton-88 Ci ND ND ND ND xenon-131m Ci ND ND ND ND xenon-133 Ci ND ND ND ND xenon-133m Ci ND ND ND ND xenon-135 Ci ND ND ND ND xenon-135m Ci ND ND ND ND xenon-138 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

2. Iodines iodine-131 Ci ND ND ND 3.68E-06 iodine-132 Ci ND ND ND ND iodine-133 Ci ND ND ND ND iodine-135 Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 3.68E-06

3. Particulates strontium-89 Ci ND ND ND ND strontium-90 Ci ND ND ND ND cesium-134 Ci ND ND ND ND cesium-137 Ci ND ND ND ND barium-lanthanum-140 Ci ND ND ND ND cobalt-58 Ci ND ND ND 2.60E-06 cobalt-60 Ci ND ND ND ND chromium-51 Ci ND ND ND ND manganese-54 Ci ND ND ND ND niobium-95 Ci ND ND ND ND iron-59 Ci ND ND ND ND carbon-14 Ci 2.05E+00 5.02E+00 3.13E+00 1.86E+00 unidentified Ci ND ND ND ND Total for period Ci 2.05E+00 5.02E+00 3.13E+00 1.86E+00

TABLE 1C EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 GASEOUS EFFLUENTS-GROUND LEVEL RELEASES BATCH Nuclides Released Unit Quarter 1

Quarter 2

Quarter 3

Quarter 4

1. Fission and activation gases argon-41 Ci ND ND ND ND krypton-85 Ci ND ND ND ND krypton-85m Ci ND ND ND ND krypton-87 Ci ND ND ND ND krypton-88 Ci ND ND ND ND xenon-131m Ci ND ND ND ND xenon-133m Ci ND ND ND ND xenon-133 Ci ND ND ND ND xenon-135 Ci ND ND ND ND xenon-135m Ci ND ND ND ND xenon-138 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

2. Iodines iodine-131 Ci ND ND ND ND iodine-132 Ci ND ND ND ND iodine-133 Ci ND ND 8.17E-07 ND iodine-135 Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 8.17E-07 0.00E+00

3. Particulates strontium-89 Ci ND ND ND ND strontium-90 Ci ND ND ND ND cesium-134 Ci ND ND ND ND cesium-136 Ci ND ND ND ND cesium-137 Ci ND ND ND ND barium-lanthanum-140 Ci ND ND ND ND cobalt-57 Ci ND ND ND ND cobalt-58 Ci ND ND ND ND cobalt-60 Ci ND ND ND ND manganese-54 Ci ND ND ND ND iron-59 Ci ND ND ND ND niobium/zirconium-95 Ci ND ND ND ND chromium-51 Ci ND ND ND ND technetium-99m Ci ND ND ND ND bromine-82 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

TABLE 1C EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 GASEOUS EFFLUENTS-GROUND LEVEL RELEASES CONTINUOUS Nuclides Released Unit Quarter 1

Quarter 2

Quarter 3

Quarter 4

1. Fission and activation gases argon-41 Ci ND ND ND ND krypton-85 Ci ND ND ND ND krypton-85m Ci ND ND ND ND krypton-87 Ci ND ND ND ND krypton-88 Ci ND ND ND ND xenon-131m Ci ND ND ND ND xenon-133m Ci ND ND ND ND xenon-133 Ci ND ND ND ND xenon-135 Ci ND ND ND ND xenon-135m Ci ND ND ND ND xenon-138 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

2. Iodines iodine-131 Ci ND ND ND ND iodine-132 Ci ND ND ND ND iodine-133 Ci ND ND ND ND iodine-135 Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 0.00E+00

3. Particulates strontium-89 Ci ND ND ND ND strontium-90 Ci ND ND ND ND cesium-134 Ci ND ND ND ND cesium-136 Ci ND ND ND ND cesium-137 Ci ND ND ND ND barium-lanthanum-140 Ci ND ND ND ND cobalt-57 Ci ND ND ND ND cobalt-58 Ci ND ND ND 3.94E-08 cobalt-60 Ci ND ND ND ND manganese-54 Ci ND ND ND ND iron-59 Ci ND ND ND ND niobium/zirconium-95 Ci ND ND ND ND chromium-51 Ci ND ND ND ND technetium-99m Ci ND ND ND ND bromine-82 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period Ci 0.00E+00 0.00E+00 0.00E+00 3.94E-08

TABLE 2A EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 LIQUID EFFLUENTS-SUMMATION OF ALL RELEASES Unit Quarter 1 Quarter 2 Quarter 3 Quarter 4 Est. Total Error, %

A. Fission and activation products

1. Total releases Ci 4.08E-03 1.77E-03 8.72E-04 8.56E-03 7.00E+00

2. Average diluted concentration during period uCi/ml 1.86E-11 7.87E-12 3.71E-12 5.99E-11

3. Percent of applicable limit 7.33E-03 3.75E-03 2.13E-02 1.71E-02 B. Tritium

1. Total release Ci 1.41E+02 1.03E+02 1.18E+03 8.35E+01 9.00E+00

2. Average diluted concentration during period uCi/ml 6.44E-07 4.58E-07 5.02E-06 5.84E-07

3. Percent of applicable limit 6.02E-03 2.88E-03 6.48E-03 1.26E-02 C. Dissolved and entrained gases

1. Total release Ci ND ND ND ND 1.90E+01

2. Average diluted concentration during period uCi/ml N/A N/A N/A N/A

3. Percent of applicable limit N/A N/A N/A N/A D. Gross alpha radioactivity

1. Total release Ci ND ND ND ND 1.00E+01 E. Volume of waste released (prior to dilution) liters 1.77E+07 2.35E+07 2.32E+07 3.95E+07 1.30E+00 F. Volume of dilution water used during period liters 2.19E+11 2.25E+11 2.35E+11 1.43E+11 9.00E+00

TABLE 2B EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 LIQUID EFFLUENTS BATCH MODE Nuclides Released Unit Quarter 1 Quarter 2 Quarter 3 Quarter 4 strontium-89 Ci ND ND ND ND strontium-90 Ci ND ND ND ND cesium-134 Ci ND ND ND ND cesium-137 Ci ND 2.46E-06 ND ND iodine-131 Ci ND ND ND ND iodine-133 Ci ND ND ND ND cobalt-57 Ci 3.28E-05 9.59E-06 ND ND cobalt-58 Ci 1.43E-03 3.73E-04 1.86E-04 2.25E-03 cobalt-60 Ci 8.23E-04 2.76E-04 6.91E-05 8.92E-05 chromium-51 Ci ND ND ND 1.30E-04 iron-55 Ci 1.70E-03 1.08E-03 ND ND iron-59 Ci ND ND ND ND zinc-65 Ci ND ND ND ND manganese-54 Ci 8.07E-05 1.50E-05 4.84E-06 3.30E-06 zirconium-niobium-95 Ci ND ND ND 3.55E-06 zirconium-97 Ci ND ND ND ND molybdenum-99 Ci ND ND ND ND technetium-99m Ci 3.21E-06 ND ND ND silver-110m Ci ND ND ND ND barium-lanthanum-140 Ci ND ND ND ND cerium-141 Ci ND ND ND ND antimony-122 Ci ND ND ND ND antimony-124 Ci ND ND ND ND antimony-125 Ci 1.24E-05 8.80E-06 6.12E-04 1.59E-03 antimony-126 Ci ND ND ND ND niobium-97 Ci ND ND ND ND tin-117m Ci ND ND ND ND sodium-24 Ci ND ND ND ND tellurium-125m Ci ND ND ND ND tellurium-129m Ci ND ND ND ND tellurium-132 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period(above)

Ci 4.08E-03 1.76E-03 8.72E-04 4.07E-03 xenon-133 Ci ND ND ND ND xenon-135 Ci ND ND ND ND

TABLE 2B EFFLUENT AND WASTE DISPOSAL ANNUAL REPORT 2024 LIQUID EFFLUENTS CONTINUOUS MODE Nuclides Released Unit Quarter 1 Quarter 2 Quarter 3 Quarter 4 strontium-89 Ci ND ND ND ND strontium-90 Ci ND ND ND ND cesium-134 Ci ND ND ND ND cesium-137 Ci ND ND ND ND iodine-131 Ci ND ND ND ND iodine-133 Ci ND ND ND ND cobalt-57 Ci ND ND ND ND cobalt-58 Ci ND ND ND 4.50E-03 cobalt-60 Ci ND ND ND ND chromium-51 Ci ND ND ND ND iron-55 Ci ND ND ND ND iron-59 Ci ND ND ND ND zinc-65 Ci ND ND ND ND manganese-54 Ci ND ND ND 2.24E-06 zirconium-niobium-95 Ci ND ND ND ND molybdenum-99 Ci ND ND ND ND technetium-99m Ci ND ND ND ND silver-110m Ci ND ND ND ND barium-lanthanum-140 Ci ND ND ND ND cerium-141 Ci ND ND ND ND antimony-122 Ci ND ND ND 1.24E-06 antimony-124 Ci ND ND ND ND antimony-125 Ci ND ND ND ND antimony-126 Ci ND ND ND ND niobium-97 Ci ND ND ND ND tin-117m Ci ND ND ND ND sodium-24 Ci ND ND ND ND tellurium-129m Ci ND ND ND ND tellurium-132 Ci ND ND ND ND unidentified Ci ND ND ND ND Total for period(above)

Ci 0.00E+00 0.00E+00 0.00E+00 4.50E-03 xenon-133 Ci ND ND ND ND xenon-135 Ci ND ND ND ND

Radiation Dose Assessment

SEABROOK STATION RADIOLOGICAL EFFLUENT IMPACT ASSESSMENT FOR 2024 (Annual Radioactive Effluent Release Report}

Prepared for Next.Em Energy Swbrook, LLC P.O. Box'.300 Seabrook, NH 03874 by Pmmatome Inc.

Lynchburg, VA 24506 Pramatome Document No. I 03-4145-000 Prcparcr-L..--'°:-

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Max K\\mlbck, Engineer Jo-Ann Pelczar. Framatome Inc.

Advisory Scii;ntist

Reference:

Framatome Calculation 32-9390859-000 i

1 Seabrook Station Radiological Effluent Impact Assessment For 2024 (Annual Radioactive Effluent Release Report)

I.

Summary Seabrook Technical Specification Sections 6.7.6.g.4 & 9 require that limitations be placed on the quarterly and annual doses or dose commitments to Members of the Public from radioactive materials in liquid and gaseous effluents released from the station to Unrestricted Areas at or beyond the site boundary conforming to the dose objectives of Appendix I to 10 CFR Part 50. Technical Specification 6.7.6.g.8 requires that limitations on the quarterly and annual air doses resulting from noble gases released in gaseous effluents to areas beyond the site boundary also conform to Appendix I to 10 CFR Part 50. In a similar fashion, Technical Specification 6.7.6.g.11 requires limitations on the annual dose or dose commitment to any Member of the Public due to radioactivity and radiation from uranium fuel cycle sources conforming to the EPA Radiation Standards in 40 CFR Part 190. The following table details the above referenced effluent dose limits.

DOSE OBJECTIVE CRITERIA FOR COMPLIANCE EFFLUENT TYPE DOSE TYPE QUARTERLY LIMITS ANNUAL LIMITS LIQUIDS (10CFR50, APP. I)

Total Body Max. Organ 1.5 mrem 5 mrem 3 mrem 10 mrem NOBLE GAS (10CFR50, APP. I)

Gamma Air Beta Air 5 mrad 10 mrad 10 mrad 20 mrad GAS PARTICULATE (10CFR50, APP. I)

Max. Organ 7.5 mrem 15 mrem TOTAL DOSE (40CFR190)

[liquids, gas, direct]

Total Body & organ Thyroid 25 mrem 75 mrem Technical Specification 6.8.1.4 and the Seabrook Offsite Dose Calculation Manual (ODCM) Part A, Section 10.2, provide that the Stations Annual Radioactive Effluent Release Report include a demonstration of compliance with the above off-site dose limitations, as well as the determination of dose impacts to Members of the Public who may be associated with permitted activities inside the site boundary.

Doses resulting from actual liquid and gaseous effluents from Seabrook Station during 2024 were calculated in accordance with Method II as defined in the Station ODCM. The calculation methods follow the models in Regulatory Guide 1.109 (Reference 1). The assessments included maximum whole body doses and organ doses from all liquid releases, maximum offsite organ doses resulting from airborne Iodine, Tritium, Carbon-14 and particulate radionuclides with half-lives greater than eight days, and maximum offsite beta air and gamma air doses from airborne noble gases. Calculated dose impacts from airborne effluents included atmospheric dispersion estimates utilizing concurrent meteorology recorded by the Stations on-site meteorological tower. In addition, the potential direct dose from fixed radiation

2 sources from both plant operations and dry fuel storage were evaluated as part of the assessment required under 40 CFR Part 190 for doses from the uranium fuel cycle.

Doses were also calculated for three special receptor locations inside the site boundary where the public might be granted access for recreational or educational purposes. The Science and Nature Center is located in the southwest portion of the site and offers educational opportunities on nuclear power and the environment. The Fitness Center is located in the Hi-Rise office building, approximately 384 meters WSW from the plant vent stack. A third on-site location considered is the Firing Range for security force training (including local law enforcement), which straddles the West site boundary at approximately 974 meters from the plant vent stack. Another location which had been included in the past was the Rocks boat launching ramp in an area northeast of the main plant facilities with access to Browns Creek and the tidal marsh that borders the site. This location has been dropped from consideration of public on-site activities due to restricted public access limitation as a result of security and safety concerns and abandonment of the boat launching ramp.

All calculated liquid and gaseous pathway doses for the 2024 reporting period are well below the dose criteria of 10 CFR Part 50, Appendix I, and the dose limits for effluent releases stated in the ODCM. In addition, the total dose to the most limiting Member of the Public due to the combined exposure to plant liquid and gaseous effluents and direct radiation from fixed plant and dry fuel storage sources was below the dose standards of 40 CFR Part 190.

3 II.

Method for Calculating the Total Body and Maximum Organ Doses Resulting from Liquid Releases Liquid waste generated during plant operations is processed and discharged to the environment via the stations circulating water cooling system. The cooling system utilizes an offshore-submerged multi-port diffuser discharge for rapid dissipation and mixing of liquid effluents in the ocean environment. A 22-port diffuser section of the discharge system is located in approximately 50 to 60 feet of water with each nozzle 7 to 10 feet above the sea floor. Eleven riser shafts, with two discharge nozzles for each diffuser, are spaced about 100 feet apart over a distance of about 1000 feet. Water is discharged in a generally eastward direction away from the shoreline through the multiport diffuser, beginning at a location over one mile offshore. During power operations, these high velocity jets passively entrain about ten volumes of fresh water into the near field jet-mixing region before the plume reaches the water surface. This arrangement also effectively prevents the discharge plume (at least to the 1 degree or 40 to 1 dilution isopleth) from impacting the shoreline over the tidal cycle.

During shutdown periods, the high velocity jet mixing created by the normal circulating water flow at the diffuser nozzles is reduced. However, mixing within the discharge tunnel water volume is significantly increased due to the long transit time for batch discharges to travel the three miles from the plant through the 19-foot diameter tunnels to the diffuser nozzles. Additional mixing of the effluent in the near field assures that an equivalent overall 10 to 1 dilution occurs by the time the effluent reaches the ocean surface.

The exposure pathways considered in the calculations of total body and maximum organ doses resulting from liquid discharges from Seabrook Station are limited to ingestion of aquatic foods and exposure to shoreline deposits. The dose calculations do not include the ingestion of potable water or irrigated vegetation as potential exposure pathways because the liquid effluents from the plant are discharged into salt water.

The dose assessment models utilized in the Offsite Dose Calculation Manual (Reference 2) are taken from Regulatory Guide 1.109 (Reference 1). The total body and organ doses are evaluated for each of the four age groups (i.e., infant, child, teen and adult) to determine the maximum total body dose and maximum organ dose via all existing exposure pathways (i.e., fish and aquatic invertebrate ingestion, and shoreline exposure) to an age-dependent individual from all detected radionuclides in plant releases. The values for the various factors considered in the model equations are provided in Regulatory Guide 1.109 and the ODCM (see Table D). The flow rate (F) of the liquid effluent and the radionuclide activities (Qi) are measured specifically prior to each liquid release. The values for half-lives for radionuclides (T1/2) and their radioactive decay constants (i) have been taken from Kocher (Reference 3).

Table A presents the calculated liquid pathway doses for each calendar quarter and total for the year. The calculated annual doses as a percent of the applicable regulatory limits are shown in Table C.

The estimated quarterly and annual doses resulting from liquid effluents to members of the public are well below all dose limit criteria.

4 III.

Method for Calculating the Gamma and Beta Air Doses from Noble Gases Gamma and beta air doses due to noble gases in gaseous effluents are calculated for several receptor locations when noble gases are recorded in effluents. Those locations include the points in each of the sixteen principle compass directions of estimated highest off-site ground level air concentration of radioactive material, site boundary (or closest point on the opposite shoreline in directions which are bordered by the tidal marsh), nearest resident, nearest vegetable garden, and nearest milk animal within five miles. The special on-site receptor locations (Science and Nature Center, the Fitness Center and the Firing Range) are evaluated for whole body dose to an individual from the noble gas component of effluents predicted to pass nearby.

Atmospheric dispersion factors (i.e., X/Q factors) calculated from recorded concurrent site meteorological data (i.e., meteorological data measurements taken during the time of the release) are used in the estimation of receptor specific air concentrations due to station effluents. The atmospheric dispersion estimations utilize methodology generally consistent with US NRC Regulatory Guide 1.111 (Reference 4). Beta air doses use undepleted X/Qs and assume a semi-infinite plume at the point of exposure. Gamma air doses are calculated using the finite cloud model presented in Meteorology and Atomic Energy - 1968 (Reference 5). That model is implemented through the definition of an effective gamma atmospheric dispersion factor [X/Q] (Reference 6) and the replacement of the undepleted X/Q in the infinite cloud dose equation by [X/Q].

The release point of effluents is also considered in the atmospheric dispersion calculation. The primary vent stack is treated as a mixed-mode release, as defined in Regulatory Guide 1.111 (Reference 4). These effluents are considered to be part-time ground-level / part-time elevated releases, depending on the ratio of primary vent stack exit velocity relative to the speed of prevailing wind. All other release points (e.g., Turbine Building and Chemistry lab hoods) are considered ground-level releases. The beta air and gamma air dose calculations are consistent with the models presented in Regulatory Guide 1.109 (Reference 1). The values for the dose factors, DFi and DFi, have been taken from Table B-1 in Regulatory Guide 1.109.

Table A presents the calculated maximum off-site gamma air and beta air doses for each calendar quarter and year. The calculated annual doses as a percent of the applicable regulatory limit are shown in Table C. The estimated quarterly and annual air doses resulting from noble gas effluents are well below all dose limit criteria.

5 IV.

Method for Calculating the Critical Organ Dose Resulting from Iodines, Tritium, Carbon-14 and Particulates with T 1/2 Greater than 8 Days in Gaseous Releases Regulatory Guide 1.109 (Reference 1) dose models are applied in the calculation of the critical organ doses from Iodines, Tritium, Carbon-14 and particulate radionuclides released into the atmosphere during the reporting period. Atmospheric dispersion and deposition factors (i.e., depleted X/Q and D/Q factors) calculated with concurrent meteorological data (i.e., meteorological data measurements taken during the time of the release) are used in the determination of gaseous pathway doses. The dispersion models are described in Section B.7.3.2 & B.7.3.3 of the Seabrook ODCM.

Potential exposure pathways associated with gaseous effluent are (i) external irradiation from radioactivity deposited on the ground surface, (ii) inhalation, and (iii) ingestion of vegetables (both fresh leafy and stored) and milk. Dose estimates were determined for the site boundary and for the locations of the nearest resident, vegetable garden, and milk animal in each of the sixteen principle compass directions. The locations of the nearest resident, vegetable garden and milk animal in each sector were identified by the 2024 Annual Land Use Census as required by ODCM Control C.9.2.1 (see Table F).

Conservatism in the dose estimates was maintained by assuming that the vegetable garden pathway was active at each milk animal location. Milk animals were assumed to receive their entire intake from pasture during the second and third quarters. This is a conservative assumption because most dairy operations utilize supplemental feeding when animals are on pasture, or actually restrict animals to full time silage feeding throughout the entire year. Table E provides the reference sources for dose model parameter assumptions used in the dose assessment.

In June 2009, the NRC issued Revision 2 of Regulatory Guide 1.21 (Reference 7) which introduced the term principal radionuclide in a risk informed or dose context. A radionuclide can be considered a principal radionuclide if it contributes either (1) greater than 1 percent of the 10 CFR Part 50, Appendix I design objective dose for all radionuclides in the type of effluent being considered, or (2) greater than 1 percent of the activity of all radionuclides in the type of effluent being considered. In addition to natural production in the environment, Carbon-14 is also produced in nuclear reactors as a function of power output, but at amounts much less than those generated naturally or from past weapons testing. Since the time of the earlier publication of Regulatory Guide 1.21 (Revision 1) in 1974, commercial nuclear power plants have decreased total radioactive effluents (other than Carbon-14) through improved fuel performance and waste management practices to the point today that Carbon-14 could be considered a principal radionuclide under todays definition, and therefore has been included in the assessment of dose to the public from gaseous effluent releases for 2024.

The primary exposure pathways associated with Carbon-14 include inhalation and ingestion of food products that have incorporated Carbon-14 (in the form of CO2) via photosynthesis. A full years consumption of food products are assumed to be grown from the highest impacted garden during the growing season (2nd and 3rd quarters). It is also assumed that the garden grows sufficient mass to support ingestion throughout the year (i.e., the annual dose to the individual is from consumption during all four quarters).

The maximum organ doses from all radionuclides in this category of gaseous effluents were determined by summing the contributions from all exposure pathways at each location, and sorting in descending order. Doses were calculated for the whole body, GI-LLI, bone, liver, kidney, thyroid, lung, and skin for

6 adults, teenagers, children, and infants. The estimated quarterly and annual organ doses at the location of the maximally exposed individual are reported in Table A.

The estimated organ doses from Iodines, Tritium, Carbon-14 and Particulates in gaseous effluents are well below the 10 CFR Part 50, Appendix I dose criteria for the reporting period. (See Table C for calculated dose as a percentage of annual limits.)

7 V.

Total Dose (40 CFR Part 190) 40 CFR 190 states that the annual dose equivalent should not exceed 25 mrem to the whole body, 75 mrem to the Thyroid, or 25 mrem to any other organ of any Member of the Public at and beyond the site boundary from all uranium fuel cycle sources. To show compliance with this standard, the maximum doses for both the liquid and gaseous pathways from Seabrook Station are added together with the whole body dose from noble gas releases and any direct radiation component attributed to station fixed sources to the maximum receptor location. This includes the addition of spent fuel storage in a Dry Fuel Storage (DFS) facility that began operations in July 2008 with the first transfer of spent fuel assemblies into storage arrays. A second transfer of spent fuel assemblies to the DFS occurred between August and September, 2013. A third spent fuel transfer campaign was conducted during September and October of 2017. A fourth spent fuel transfer campaign was conducted during August and September of 2022, with an additional eight fuel canisters placed into storage, bringing the total to 30 canisters in storage the beginning of 4th quarter 2022. The DFS facility is located on Seabrook Station property approximately 0.38 miles West-Southwest of the Unit 1 Containment Building. Since there are no other uranium fuel cycle facilities within five miles of Seabrook Station, no additional impacts from sources beyond Seabrook Station need be considered.

The sum of the maximum annual whole body doses to Members of the Public from all exposure pathways for liquid and gaseous effluents, plus the direct external dose from plant and dry fuel storage fixed sources, was 5.35E-02 mrem to a hypothetical individual at or beyond the site boundary. The maximum organ dose (including the thyroid) to any age group from all exposure pathways including direct radiation was 2.35E-01 mrem.

Table B illustrates the total dose projections from all station sources to the maximum potential off-site individual for the year 2024 and demonstrates compliance with the EPAs environmental radiation standard for the uranium fuel cycle per 40 CFR Part 190. (See Table C for total dose as a percentage of annual limits.)

8 VI.

References

1.

Regulatory Guide 1.109, Revision 1,Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purposes of Evaluating Compliance with 10CFR Part 50, Appendix I, USNRC, October 1977.

2.

Seabrook Station Program Manual: Offsite Dose Calculation Manual (ODCM), Revision 41.

3.

Kocher, D.C., Dose-Rate Conversion Factors for Exposure to Photons and Electrons, Health Physics, Vol. 45, No. 3, Sept. 1983.

4.

Regulatory Guide 1.111, Revision 1, Method for Estimating Atmospheric Transport and Dispersion of Gaseous Effluents in Routine Releases from Light-Water Cooled Reactors, USNRC, July 1977.

5.

Slade, D.H., Meteorology and Atomic Energy - 1968, USAEC, July 1968.

6.

Hamawi, J.N., AEOLUS-2 A Computer Code for the Determination of Continuous and Intermittent-Release Atmospheric Dispersion and Deposition of Nuclear Power Plant Effluents in Open-Terrain Sites, Coastal Sites, and Deep-River Valleys for the Assessment of Ensuing Doses and Finite-Cloud Gamma Radiation Exposures, Entech Engineering, Inc., March 1988.

7.

Regulatory Guide 1.21, Revision 2, Measuring, Evaluating, and Reporting Radioactive Material in Liquid and Gaseous Effluents and Solid Waste, USNRC, June 2009.

9 Table A Seabrook Station 2024 Annual Radioactive Effluent Release Report Maximum(a) Off-Site Doses and Dose Commitments to Members of the Public Dose (mrem)(b)

Total Body Dose Max Organ Dose 5.94E-05 (1) 1.21E-04 (3) 3.78E-05 (1) 7.36E-05 (3) 3.12E-04 (1) 3.17E-04 (2) 1.54E-04 (1) 5.21E-04 (2) 5.63E-04 1.03E-03 Airborne Effluents:

Organ Dose from Carbon-14, Iodines, Tritium, and Particulates (T1/2 > 8 days) 5.69E-02 (4) 5.99E-02 (4) 5.84E-02 (4) 5.90E-02 (4) 2.34E-01 Noble Gases Beta Air (mrad) 5.07E-07 (6) 5.04E-05 (6) 8.86E-07 (6) 9.23E-05 (7) 1.44E-04 Gamma Air (mrad) 1.63E-06 (5) 1.32E-04 (6) 2.57E-06 (6) 2.65E-04 (7) 4.01E-04 Direct Dose Offsite From Station Operation(e) 0 0

0 0

0 Doses (mrem) at Receptor Locations Inside Site Boundary(d):

Science and Nature Center (SW, 488m):

Max Organ Dose (mrem) 4.56E-06 1.27E-05 4.85E-06 1.26E-06 2.34E-05 The Firing Range (W, 974m)

Max Organ Dose 7.62E-05 2.10E-04 1.36E-04 4.07E-05 4.63E-04 The Fitness Center (WSW, 384m):

Max Organ Dose (mrem) 1.74E-04 5.88E-04 1.70E-04 1.50E-04 1.08E-03

10 Table A (continued)

Seabrook Station 2024 Annual Radioactive Effluent Release Report Maximum(a) Off-Site Doses and Dose Commitments to Members of the Public NOTES:

(a)

"Maximum means the largest fraction of corresponding 10CFR50, Appendix I, dose design objective.

(b)

The numbered footnotes indicate the age group, organ, and location (compass sector and distance from the primary vent in meters) of the critical receptor, where appropriate, based on the most limiting radionuclide dose contributor (C-14).

(1) Adult (2) GI-LLI of an adult (3) Bone of a child (4) Bone of a child, W 1252 m (5) S 930 m (6) W 1005 m (7) ESE 2276 m (c)

"Maximum" dose for the year is the sum of the maximum doses for each quarter. This results in a conservative yearly dose estimate, but still well within the limits of 10CFR50.

(d)

For each special receptor location, the whole body and organ doses calculated for the airborne effluent releases were adjusted by the occupancy factors (i.e., 0.0014 for the Science and Nature Center and 0.0416 for the Fitness Center and Firing Range). The most limiting on-site location with respect to dose is estimated to be the Fitness Center located in the Hi-Rise office building due to relatively close location to the plant vent stack.

(e)

Only station sources (both plant and dry fuel storage) are considered since there are no other fuel cycle facilities within five miles of Seabrook Station site. Dosimeter data collected in 2024 for the closest off-site environmental TLD locations in each sector (as listed in Tables B.4-1 and B.4-2 of Seabrook's ODCM) were compared to preoperational data for the same locations. No statistical difference above random background variability which could be attributed to station sources was identified.

11 Table B Seabrook Station 2024 Annual Radioactive Effluent Release Report Total Dose to Maximum Off-Site Individual (40CFR190)

Release Source Total Body (mrem)

Maximum Organ(a)

(mrem)

Liquids 5.63E-04 1.03E-03 Noble Gases 2.67E-04 2.67E-04 Gaseous Iodines, Tritium, C-14 Particulates (T1/2 > 8 days) 5.27E-02 2.34E-01 Direct Radiation 0

0 Annual Total 5.35E-02 2.35E-01 (a) Maximum organ includes consideration of the thyroid.

12 Table C Seabrook Station 2024 Annual Radioactive Effluent Release Report Calculated 2024 Maximum Doses versus Applicable Limits Receptor Applicable ODCM Control ODCM Annual Limit Calculated Annual (2024)

Dose Percent of Limit Offsite Liquid Effluents Whole Body Dose C.6.2.1 3

mrem 5.63E-04 mrem 0.0188%

Organ Dose C.6.2.1 10 mrem 1.03E-03 mrem 0.0103%

Airborne Effluents Organ Dose (iodines, H-3, C-14 and part.)

C.7.3.1 15 mrem 2.34E-01 mrem 1.56%

Gamma Air Dose (noble gases)

C.7.2.1 10 mrad 4.01E-04 mrad 0.0040%

Beta Air Dose (noble gases)

C.7.2.1 20 mrad 1.44E-04 mrad 0.00072%

All Station Sources (a)

Whole Body Dose C.8.1.1 25 mrem 5.35E-02 mrem 0.214%

Organ Dose C.8.1.1 25 mrem 2.35E-01 mrem 0.94%

Onsite (Science & Nature Center, 488m SW)

Organ Dose (iodines, H-3, C-14 and part.)

C.7.3.1(b) 15 mrem 2.34E-05 mrem 0.00016%

Onsite (The Firing Range, 974m W)

Organ Dose (iodines, H-3, C-14 and part.)

C.7.3.1(b) 15 mrem 4.63E-04 mrem 0.0031%

Onsite (Fitness Center, 384m WSW)

Organ Dose (iodines, H-3, C-14 and part.)

C.7.3.1(b) 15 mrem 1.08E-03 mrem 0.0072%

(a) The all station sources doses are the sum of the whole body doses and maximum organ doses from liquid, noble gas, and gaseous iodines/tritium/carbon-14/particulate releases as well as direct radiation from fixed station sources (both plant facilities and dry fuel storage).

(b) ODCM Part A, Section 10.2 states that the annual effluent report shall include an assessment of the radiation doses from radioactive liquids and gaseous effluents to members of the public due to their activities inside the site boundary during the report period. The referenced limits (C.7.2.1 & C.7.3.1) are the acceptable doses from liquid and gaseous effluents to areas at and beyond the site boundary and are considered to be appropriate for comparison purposes.

13 Table D Seabrook Station 2024 Annual Radioactive Effluent Release Report Sources of the Values of Factors Used in Liquid Dose Equations Factor Definition Source Uap Usage factor Table B.7-1, Station ODCM Mp Mixing ratio Section B.7.1, Station ODCM (value=0.1 for aquatic foods and 0.025 for shoreline)

Bip Equilibrium bioaccumulation factor Table A-1, Reg. Guide 1.109 Daipj Dose factor Tables E-11 through E-14, Reg. Guide 1.109 tp Nuclide transit time Table E-15, Reg. Guide 1.109 Kc Transfer coefficient from water to sediment Reg. Guide 1.109 tb Period of activity buildup in sediment or soil Table B.7-2, Station ODCM W

Shoreline width factor Table A-2, Reg. Guide 1.109 (value = 0.5)

14 Table E Seabrook Station 2024 Annual Radioactive Effluent Release Report Sources of Values for the Factors Used in Dose Equations for Gaseous Releases Factor Definition Source tb Period of activity buildup in sediment or soil Table B.7-2, Station ODCM i

Nuclide decay constant Kocher (Reference 3)

DFGij Ground plane dose factor Table E-6, Reg. Guide 1.109

[X/Q]

Atmospheric dispersion factor (non-depleted)

Calculated following Reg. Guide 1.111

[X/Q]D Atmospheric dispersion factor (depleted)

Calculated following Reg. Guide 1.111 Ra Breathing rate Table B.7-3, Station ODCM DFAija Inhalation dose factor Tables E-7 through E-10, Reg. Guide 1.109 di Nuclide deposition rate Reg. Guide 1.109 P

Soil surface density Table B.7-2, Station ODCM te Crop, leafy vegetable, or pasture grass exposure period Table B.7-2, Station ODCM th Average time from crop harvest to consumption Table B.7-2, Station ODCM Yv Agricultural productivity by unit area Table B.7-2, Station ODCM r

Fraction of deposited activity retained on crops, leafy vegetables, or pasture grass Table E-15, Reg. Guide 1.109 Biv Stable element transfer coefficient from soil to produce, leafy vegetable, or pasture grass Table E-1, Reg. Guide 1.109 p

Fractional equilibrium ratio Reg. Guide 1.109 H

Ambient absolute humidity Table B.7-2, Station ODCM

15 Table E (continued)

Seabrook Station 2024 Annual Radioactive Effluent Release Report Sources of Values for the Factors Used in Dose Equations for Gaseous Releases Factor Definition Source Fm Stable element transfer coefficient from feed to milk Tables E-1 and E-2, Reg. Guide 1.109 tf Average time from feed to milk to consumption Reg. Guide 1.109 fp Fraction of the year that animals graze on pasture Table B.7-2, Station ODCM fs Fraction daily feed pasture grass Table B.7-2, Station ODCM Ff Stable element transfer coefficient from feed to meat Table E-1, Reg. Guide 1.109 ts Average time from meat animal slaughter to consumption Table E-15, Reg. Guide 1.109 DFIija Ingestion dose factor Tables E-11 through E-14, Reg. Guide 1.109 U

v a

Annual intake of produce Table B.7-3, Station ODCM U

m a

Annual intake of milk Table B.7-3, Station ODCM U

F a

Annual intake of meat Table B.7-3, Station ODCM U

L a

Annual intake of leafy vegetables Table B.7-3, Station ODCM fg Ingestion rate fractions for garden produce Reg. Guide 1.109 fl Ingestion rate fractions for garden leafy vegetables Reg. Guide 1.109 w

Rate constant for activity removal from plant and leaf surfaces by weathering Table E-15, Reg. Guide 1.109 QF Animal consumption rate Table E-3, Reg. Guide 1.109

16 Table F Seabrook Station 2024 Annual Radioactive Effluent Release Report Receptor Locations* for Seabrook Station Sector Nearest Resident km (miles)

Nearest Garden km (miles)

Milk Animals within 5 Mile Radius km (miles)

N 2.78 (1.73) 3.99 (2.48)

NNE 3.05 (1.89) 3.32 (2.06)

NE 2.94 (1.82) 4.17 (2.59)

ENE 2.33 (1.44) 2.53 (1.57)

E 2.56 (1.59)

ESE 2.44 (1.52) 3.12 (1.94)

SE 2.39 (1.48)

SSE 1.66 (1.03) 6.52 (4.05)

S 1.21 (0.75) 1.40 (0.87)

SSW 1.12 (0.69) 1.22 (0.76)

SW 1.13 (0.70) 1.73 (1.08)

WSW 1.88 (1.17) 2.61 (1.62)

W 1.25 (0.78) 1.55 (0.96)

WNW 1.11 (0.69) 3.08 (1.92)

NW 1.22 (0.76) 2.18 (1.36) 6.93 (4.30)

NNW 1.04 (0.64) 2.07 (1.29)

Locations based on 2024 Land Use Census.

List of Appendices Appendix Title A

Offsite Dose Calculation Manual B

Process Control Program C

Liquid Holdup Tanks D

Radwaste Treatment Systems E

Unplanned Releases

Appendix A Offsite Dose Calculation Manual Requirement:

Technical Specification 6.13 requires that licensee initiated changes to the Offsite Dose Calculation Manual be submitted to the Commission in the Annual Radioactive Effluent Release Report for the period in which the change(s) was made effective. Include in this changes to the Radiological Environmental Program in accordance with Offsite Dose Calculation Manual (ODCM)-C.9.1.1 and -C.9.2.1.

Response

No changes were made to the Offsite Dose Calculation Manual in 2024.

Appendix B Process Control Program Requirement:

Technical Specification 6.12 requires that licensee initiated changes to the Process Control Program be submitted to the Commission in the Annual Radioactive Effluent Release Report for the period in which the change(s) was made.

Response

No changes were made to the Process Control Program in 2024.

Appendix C Liquid Holdup Tank Requirement:

Technical Specification 3.11.1.4 limits the quantity of radioactive material contained in any outside temporary tank. With the quantity of radioactive material in any outside temporary tank exceeding the limits of Technical Specification 3.11.1.4, a description of the events leading to this condition is required in the next Annual Effluent Release Report in accordance with Tech. Spec. 6.8.1.4.

Response

A review of the period January 1, 2024 to December 31, 2024, indicated there was no radioactive material stored in any temporary outdoor tank that exceeded the limits of T.S. 3.11.1.4.

Appendix D Radwaste Treatment Systems Requirement:

Technical Specification 6.14.1a requires that licensee initiated changes to the Radwaste Treatment Systems (liquid, gaseous, and solid) be submitted to the Commission in the Annual Radioactive Effluent Release Report for the period in which the change was made.

Response

For 2024 NextEra Energy Seabrook, LLC, will submit any changes in the Radwaste Treatment Systems (liquid, gaseous and solid) as part of the FSAR update.

Appendix E Unplanned Releases Requirement:

Technical Specification 6.8.1.4 requires a list and description of unplanned releases from the site to UNRESTRICTED AREAS of radioactive materials in gaseous and liquid effluents made during the reporting period.

Submit all groundwater monitoring well sample results and a description of any significant onsite leaks/spills that impact groundwater

Response

A review of the period January 1, 2024 to December 31, 2024, indicated no unplanned, unanticipated or abnormal releases from the site to unrestricted areas of radioactive materials of gaseous or liquid effluents.

See next sheet for groundwater monitoring well results.

2024 Ground Water Monitoring Well Tritium Data Date/Time BD-1 BD-2 BD-3 BD-4 BD-5 BD-6 BU-1 SC-1 SD-1 SD-2 SD-3 SD-4 SD-5 SU-1 SW-1 SW-2 SW-3 SW-4 SW-5 SW-6 SU-10 SU-11 BU-10 BU-11 TW-1 TW-2 TW-3 (pCi/L)(pCi/L)(pCi/L (pCi/L)(pCi/L)(pCi/L)(pCi/L)(pCi/L)(pCi/L) (pCi/L (pCi/L)(pCi/L)(pCi/L (pCi/L)(pCi/L)(pCi/L)(pCi/L (pCi/L (pCi/L) (pCi/L) (pCi/L) (pCi/L) (pCi/L)(pCi/L) (pCi/L) (pCi/L) (pCi/L) 03/06/24

<558

<559 07/15/24

<618

<611 09/12/24

<592

<595 12/02/24

<584

<565

<587

<590

<586

<584 N/A N/A N/A N/A N/A

<587

<586

<590 N/A

<589 N/A N/A

<586 N/A

<583

<586 N/A N/A N/A Paired well locations:

Selected well locations:

BD-1 Southwest of plant, south of cooling tower outside PA fence SW-1 South of Fuel Storage Building (Indicator location) inside PA fence SD-1 / BD-2 South of plant near seawall inside PA fence SW-2 East of plant near Service Water Pump House inside PA fence SD-2 / BD-3 East of plant inside owner controlled area SW-3 Southwest of plant near Unit 1 to Unit 2 tunnel inside PA fence SD-3 / BD-4 Northeast of plant inside owner controlled area SW-4 South of waste process building / steam generator blowdown room inside PA fence SD-4 / BD-5 Southwest of plant, south of cooling tower inside owner controlled area SW-5 West of service water building inside PA fence SD-5 / BD-6 South of Unit 2 containment equipment hatch outside PA fence SW-6 Southwest of demineralized tank 259 inside PA fence SU-1 / BU-1 Northwest of plant (Background location) inside owner controlled area TW-1 Southeast of plant inside owner controlled area outside PA fence SU-10 / BU-10 North / northwest of plant inside PA fence TW-2 Southeast of plant inside owner controlled area outside PA fence SU-11 / BU-11 North of plant inside PA fence TW-3 Southeast of plant inside owner controlled area outside PA fence Definitions:

Note: All sample results in pCi/L S = Shallow C = Cross gradient U = up gradient W = well B = Bedrock D = down gradient T = temporary Joint Frequency Distribution of Wind Speed, Wind Direction, and Atmospheric Stability

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS A CLASS FREQUENCY (PERCENT) = 33.47 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 1 0 1 1 0 0 0 0 0 1 2 2 2 0 0 0 10 (1) 0.00 0.03 0.00 0.03 0.03 0.00 0.00 0.00 0.00 0.00 0.03 0.07 0.07 0.07 0.00 0.00 0.00 0.34 (2) 0.00 0.01 0.00 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.01 0.02 0.02 0.02 0.00 0.00 0.00 0.11 C-3 16 25 21 35 21 13 19 32 31 30 29 24 46 22 30 23 0 417 (1) 0.55 0.85 0.72 1.20 0.72 0.44 0.65 1.09 1.06 1.03 0.99 0.82 1.57 0.75 1.03 0.79 0.00 14.26 (2) 0.18 0.29 0.24 0.40 0.24 0.15 0.22 0.37 0.35 0.34 0.33 0.27 0.53 0.25 0.34 0.26 0.00 4.77 4-7 29 27 97 69 133 109 135 76 71 93 136 172 151 120 74 43 0 1535 (1) 0.99 0.92 3.32 2.36 4.55 3.73 4.62 2.60 2.43 3.18 4.65 5.88 5.16 4.10 2.53 1.47 0.00 52.48 (2) 0.33 0.31 1.11 0.79 1.52 1.25 1.54 0.87 0.81 1.06 1.56 1.97 1.73 1.37 0.85 0.49 0.00 17.56 8-12 2 1 77 74 117 70 56 20 15 75 112 73 65 65 72 10 0 904 (1) 0.07 0.03 2.63 2.53 4.00 2.39 1.91 0.68 0.51 2.56 3.83 2.50 2.22 2.22 2.46 0.34 0.00 30.91 (2) 0.02 0.01 0.88 0.85 1.34 0.80 0.64 0.23 0.17 0.86 1.28 0.84 0.74 0.74 0.82 0.11 0.00 10.34 13-18 0 0 13 0 3 0 4 5 5 4 4 1 2 5 11 1 0 58 (1) 0.00 0.00 0.44 0.00 0.10 0.00 0.14 0.17 0.17 0.14 0.14 0.03 0.07 0.17 0.38 0.03 0.00 1.98 (2) 0.00 0.00 0.15 0.00 0.03 0.00 0.05 0.06 0.06 0.05 0.05 0.01 0.02 0.06 0.13 0.01 0.00 0.66 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 ALL SPEEDS 47 54 208 179 275 192 214 133 122 203 282 272 266 214 187 77 0 2925 (1) 1.61 1.85 7.11 6.12 9.40 6.56 7.32 4.55 4.17 6.94 9.64 9.30 9.09 7.32 6.39 2.63 0.00 100.00 (2) 0.54 0.62 2.38 2.05 3.15 2.20 2.45 1.52 1.40 2.32 3.23 3.11 3.04 2.45 2.14 0.88 0.00 33.47 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS B CLASS FREQUENCY (PERCENT) = 3.83 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 0 0 1 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 C-3 1 3 1 2 4 4 2 0 5 3 4 4 7 4 5 3 0 52 (1) 0.30 0.90 0.30 0.60 1.19 1.19 0.60 0.00 1.49 0.90 1.19 1.19 2.09 1.19 1.49 0.90 0.00 15.52 (2) 0.01 0.03 0.01 0.02 0.05 0.05 0.02 0.00 0.06 0.03 0.05 0.05 0.08 0.05 0.06 0.03 0.00 0.60 4-7 3 4 7 15 13 6 7 7 5 6 10 20 19 14 9 4 0 149 (1) 0.90 1.19 2.09 4.48 3.88 1.79 2.09 2.09 1.49 1.79 2.99 5.97 5.67 4.18 2.69 1.19 0.00 44.48 (2) 0.03 0.05 0.08 0.17 0.15 0.07 0.08 0.08 0.06 0.07 0.11 0.23 0.22 0.16 0.10 0.05 0.00 1.71 8-12 1 0 5 2 15 6 7 5 1 1 14 12 13 17 4 0 0 103 (1) 0.30 0.00 1.49 0.60 4.48 1.79 2.09 1.49 0.30 0.30 4.18 3.58 3.88 5.07 1.19 0.00 0.00 30.75 (2) 0.01 0.00 0.06 0.02 0.17 0.07 0.08 0.06 0.01 0.01 0.16 0.14 0.15 0.19 0.05 0.00 0.00 1.18 13-18 0 0 3 0 2 0 0 0 1 0 0 0 2 12 10 0 0 30 (1) 0.00 0.00 0.90 0.00 0.60 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.60 3.58 2.99 0.00 0.00 8.96 (2) 0.00 0.00 0.03 0.00 0.02 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.02 0.14 0.11 0.00 0.00 0.34 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 5 7 16 19 34 16 16 12 12 11 28 36 41 47 28 7 0 335 (1) 1.49 2.09 4.78 5.67 10.15 4.78 4.78 3.58 3.58 3.28 8.36 10.75 12.24 14.03 8.36 2.09 0.00 100.00 (2) 0.06 0.08 0.18 0.22 0.39 0.18 0.18 0.14 0.14 0.13 0.32 0.41 0.47 0.54 0.32 0.08 0.00 3.83 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS C CLASS FREQUENCY (PERCENT) = 5.39 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 0 0 0 0 0 0 0 0 0 1 0 0 0 0 0 1 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.21 0.00 0.00 0.00 0.00 0.00 0.21 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.01 C-3 5 6 3 3 1 2 0 3 6 8 5 5 5 6 2 7 0 67 (1) 1.06 1.27 0.64 0.64 0.21 0.42 0.00 0.64 1.27 1.70 1.06 1.06 1.06 1.27 0.42 1.49 0.00 14.23 (2) 0.06 0.07 0.03 0.03 0.01 0.02 0.00 0.03 0.07 0.09 0.06 0.06 0.06 0.07 0.02 0.08 0.00 0.77 4-7 7 6 6 10 8 10 13 7 8 3 15 23 16 26 13 8 0 179 (1) 1.49 1.27 1.27 2.12 1.70 2.12 2.76 1.49 1.70 0.64 3.18 4.88 3.40 5.52 2.76 1.70 0.00 38.00 (2) 0.08 0.07 0.07 0.11 0.09 0.11 0.15 0.08 0.09 0.03 0.17 0.26 0.18 0.30 0.15 0.09 0.00 2.05 8-12 8 1 11 8 14 5 7 3 2 3 7 12 24 35 23 8 0 171 (1) 1.70 0.21 2.34 1.70 2.97 1.06 1.49 0.64 0.42 0.64 1.49 2.55 5.10 7.43 4.88 1.70 0.00 36.31 (2) 0.09 0.01 0.13 0.09 0.16 0.06 0.08 0.03 0.02 0.03 0.08 0.14 0.27 0.40 0.26 0.09 0.00 1.96 13-18 1 0 2 0 1 0 0 0 0 0 1 1 4 21 17 1 0 49 (1) 0.21 0.00 0.42 0.00 0.21 0.00 0.00 0.00 0.00 0.00 0.21 0.21 0.85 4.46 3.61 0.21 0.00 10.40 (2) 0.01 0.00 0.02 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.01 0.01 0.05 0.24 0.19 0.01 0.00 0.56 19-24 0 0 0 0 2 0 0 0 0 0 0 0 0 0 2 0 0 4 (1) 0.00 0.00 0.00 0.00 0.42 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.42 0.00 0.00 0.85 (2) 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.05 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 21 13 22 21 26 17 20 13 16 14 28 42 49 88 57 24 0 471 (1) 4.46 2.76 4.67 4.46 5.52 3.61 4.25 2.76 3.40 2.97 5.94 8.92 10.40 18.68 12.10 5.10 0.00 100.00 (2) 0.24 0.15 0.25 0.24 0.30 0.19 0.23 0.15 0.18 0.16 0.32 0.48 0.56 1.01 0.65 0.27 0.00 5.39 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS D CLASS FREQUENCY (PERCENT) = 31.87 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 2 1 1 0 2 2 2 2 0 0 1 1 2 3 2 1 0 22 (1) 0.07 0.04 0.04 0.00 0.07 0.07 0.07 0.07 0.00 0.00 0.04 0.04 0.07 0.11 0.07 0.04 0.00 0.79 (2) 0.02 0.01 0.01 0.00 0.02 0.02 0.02 0.02 0.00 0.00 0.01 0.01 0.02 0.03 0.02 0.01 0.00 0.25 C-3 31 14 18 18 9 10 12 13 13 26 38 36 45 48 35 36 0 402 (1) 1.11 0.50 0.65 0.65 0.32 0.36 0.43 0.47 0.47 0.93 1.36 1.29 1.62 1.72 1.26 1.29 0.00 14.43 (2) 0.35 0.16 0.21 0.21 0.10 0.11 0.14 0.15 0.15 0.30 0.43 0.41 0.51 0.55 0.40 0.41 0.00 4.60 4-7 86 61 31 30 53 47 36 49 49 52 75 138 131 124 129 86 0 1177 (1) 3.09 2.19 1.11 1.08 1.90 1.69 1.29 1.76 1.76 1.87 2.69 4.96 4.70 4.45 4.63 3.09 0.00 42.26 (2) 0.98 0.70 0.35 0.34 0.61 0.54 0.41 0.56 0.56 0.60 0.86 1.58 1.50 1.42 1.48 0.98 0.00 13.47 8-12 46 11 37 55 42 32 11 25 18 24 41 49 92 215 131 36 0 865 (1) 1.65 0.39 1.33 1.97 1.51 1.15 0.39 0.90 0.65 0.86 1.47 1.76 3.30 7.72 4.70 1.29 0.00 31.06 (2) 0.53 0.13 0.42 0.63 0.48 0.37 0.13 0.29 0.21 0.27 0.47 0.56 1.05 2.46 1.50 0.41 0.00 9.90 13-18 0 5 11 17 10 10 2 2 1 1 2 2 6 99 73 1 0 242 (1) 0.00 0.18 0.39 0.61 0.36 0.36 0.07 0.07 0.04 0.04 0.07 0.07 0.22 3.55 2.62 0.04 0.00 8.69 (2) 0.00 0.06 0.13 0.19 0.11 0.11 0.02 0.02 0.01 0.01 0.02 0.02 0.07 1.13 0.84 0.01 0.00 2.77 19-24 0 1 3 8 17 3 0 0 0 0 0 0 0 14 11 0 0 57 (1) 0.00 0.04 0.11 0.29 0.61 0.11 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.50 0.39 0.00 0.00 2.05 (2) 0.00 0.01 0.03 0.09 0.19 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.16 0.13 0.00 0.00 0.65 GT 24 0 0 0 4 15 0 0 0 0 0 0 0 0 1 0 0 0 20 (1) 0.00 0.00 0.00 0.14 0.54 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.00 0.00 0.72 (2) 0.00 0.00 0.00 0.05 0.17 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.23 ALL SPEEDS 165 93 101 132 148 104 63 91 81 103 157 226 276 504 381 160 0 2785 (1) 5.92 3.34 3.63 4.74 5.31 3.73 2.26 3.27 2.91 3.70 5.64 8.11 9.91 18.10 13.68 5.75 0.00 100.00 (2) 1.89 1.06 1.16 1.51 1.69 1.19 0.72 1.04 0.93 1.18 1.80 2.59 3.16 5.77 4.36 1.83 0.00 31.87 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS E CLASS FREQUENCY (PERCENT) = 14.80 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 2 3 3 0 1 1 0 2 2 1 1 6 6 4 1 0 0 33 (1) 0.15 0.23 0.23 0.00 0.08 0.08 0.00 0.15 0.15 0.08 0.08 0.46 0.46 0.31 0.08 0.00 0.00 2.55 (2) 0.02 0.03 0.03 0.00 0.01 0.01 0.00 0.02 0.02 0.01 0.01 0.07 0.07 0.05 0.01 0.00 0.00 0.38 C-3 19 10 14 15 17 6 6 12 18 26 52 82 114 105 63 26 0 585 (1) 1.47 0.77 1.08 1.16 1.31 0.46 0.46 0.93 1.39 2.01 4.02 6.34 8.82 8.12 4.87 2.01 0.00 45.24 (2) 0.22 0.11 0.16 0.17 0.19 0.07 0.07 0.14 0.21 0.30 0.60 0.94 1.30 1.20 0.72 0.30 0.00 6.69 4-7 16 3 7 9 15 13 6 12 3 14 62 149 84 122 76 23 0 614 (1) 1.24 0.23 0.54 0.70 1.16 1.01 0.46 0.93 0.23 1.08 4.80 11.52 6.50 9.44 5.88 1.78 0.00 47.49 (2) 0.18 0.03 0.08 0.10 0.17 0.15 0.07 0.14 0.03 0.16 0.71 1.71 0.96 1.40 0.87 0.26 0.00 7.03 8-12 0 1 2 5 5 2 1 2 0 0 12 9 1 8 10 0 0 58 (1) 0.00 0.08 0.15 0.39 0.39 0.15 0.08 0.15 0.00 0.00 0.93 0.70 0.08 0.62 0.77 0.00 0.00 4.49 (2) 0.00 0.01 0.02 0.06 0.06 0.02 0.01 0.02 0.00 0.00 0.14 0.10 0.01 0.09 0.11 0.00 0.00 0.66 13-18 0 0 0 1 2 0 0 0 0 0 0 0 0 0 0 0 0 3 (1) 0.00 0.00 0.00 0.08 0.15 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.23 (2) 0.00 0.00 0.00 0.01 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 37 17 26 30 40 22 13 28 23 41 127 246 205 239 150 49 0 1293 (1) 2.86 1.31 2.01 2.32 3.09 1.70 1.01 2.17 1.78 3.17 9.82 19.03 15.85 18.48 11.60 3.79 0.00 100.00 (2) 0.42 0.19 0.30 0.34 0.46 0.25 0.15 0.32 0.26 0.47 1.45 2.81 2.35 2.73 1.72 0.56 0.00 14.80 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS F CLASS FREQUENCY (PERCENT) = 5.98 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 1 1 1 3 2 0 1 0 1 0 0 3 7 2 1 2 0 25 (1) 0.19 0.19 0.19 0.57 0.38 0.00 0.19 0.00 0.19 0.00 0.00 0.57 1.34 0.38 0.19 0.38 0.00 4.78 (2) 0.01 0.01 0.01 0.03 0.02 0.00 0.01 0.00 0.01 0.00 0.00 0.03 0.08 0.02 0.01 0.02 0.00 0.29 C-3 6 7 5 8 4 0 3 2 3 5 24 36 107 100 62 18 0 390 (1) 1.15 1.34 0.96 1.53 0.76 0.00 0.57 0.38 0.57 0.96 4.59 6.88 20.46 19.12 11.85 3.44 0.00 74.57 (2) 0.07 0.08 0.06 0.09 0.05 0.00 0.03 0.02 0.03 0.06 0.27 0.41 1.22 1.14 0.71 0.21 0.00 4.46 4-7 0 0 0 1 1 0 0 1 0 0 5 14 17 34 31 4 0 108 (1) 0.00 0.00 0.00 0.19 0.19 0.00 0.00 0.19 0.00 0.00 0.96 2.68 3.25 6.50 5.93 0.76 0.00 20.65 (2) 0.00 0.00 0.00 0.01 0.01 0.00 0.00 0.01 0.00 0.00 0.06 0.16 0.19 0.39 0.35 0.05 0.00 1.24 8-12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 13-18 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 7 8 6 12 7 0 4 3 4 5 29 53 131 136 94 24 0 523 (1) 1.34 1.53 1.15 2.29 1.34 0.00 0.76 0.57 0.76 0.96 5.54 10.13 25.05 26.00 17.97 4.59 0.00 100.00 (2) 0.08 0.09 0.07 0.14 0.08 0.00 0.05 0.03 0.05 0.06 0.33 0.61 1.50 1.56 1.08 0.27 0.00 5.98 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS G CLASS FREQUENCY (PERCENT) = 4.66 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 1 1 0 1 0 0 0 0 0 1 7 6 6 2 2 0 27 (1) 0.00 0.25 0.25 0.00 0.25 0.00 0.00 0.00 0.00 0.00 0.25 1.72 1.47 1.47 0.49 0.49 0.00 6.63 (2) 0.00 0.01 0.01 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.01 0.08 0.07 0.07 0.02 0.02 0.00 0.31 C-3 1 1 2 7 3 2 1 1 2 1 13 24 101 136 48 10 0 353 (1) 0.25 0.25 0.49 1.72 0.74 0.49 0.25 0.25 0.49 0.25 3.19 5.90 24.82 33.42 11.79 2.46 0.00 86.73 (2) 0.01 0.01 0.02 0.08 0.03 0.02 0.01 0.01 0.02 0.01 0.15 0.27 1.16 1.56 0.55 0.11 0.00 4.04 4-7 0 0 0 0 0 0 0 0 0 0 0 2 4 12 9 0 0 27 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.49 0.98 2.95 2.21 0.00 0.00 6.63 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.05 0.14 0.10 0.00 0.00 0.31 8-12 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 13-18 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 1 2 3 7 4 2 1 1 2 1 14 33 111 154 59 12 0 407 (1) 0.25 0.49 0.74 1.72 0.98 0.49 0.25 0.25 0.49 0.25 3.44 8.11 27.27 37.84 14.50 2.95 0.00 100.00 (2) 0.01 0.02 0.03 0.08 0.05 0.02 0.01 0.01 0.02 0.01 0.16 0.38 1.27 1.76 0.68 0.14 0.00 4.66 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 43.0 FT WIND DATA STABILITY CLASS ALL CLASS FREQUENCY (PERCENT) = 100.00 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 5 7 6 4 7 3 3 4 3 2 4 20 23 17 6 5 0 119 (1) 0.06 0.08 0.07 0.05 0.08 0.03 0.03 0.05 0.03 0.02 0.05 0.23 0.26 0.19 0.07 0.06 0.00 1.36 (2) 0.06 0.08 0.07 0.05 0.08 0.03 0.03 0.05 0.03 0.02 0.05 0.23 0.26 0.19 0.07 0.06 0.00 1.36 C-3 79 66 64 88 59 37 43 63 78 99 165 211 425 421 245 123 0 2266 (1) 0.90 0.76 0.73 1.01 0.68 0.42 0.49 0.72 0.89 1.13 1.89 2.41 4.86 4.82 2.80 1.41 0.00 25.93 (2) 0.90 0.76 0.73 1.01 0.68 0.42 0.49 0.72 0.89 1.13 1.89 2.41 4.86 4.82 2.80 1.41 0.00 25.93 4-7 141 101 148 134 223 185 197 152 136 168 303 518 422 452 341 168 0 3789 (1) 1.61 1.16 1.69 1.53 2.55 2.12 2.25 1.74 1.56 1.92 3.47 5.93 4.83 5.17 3.90 1.92 0.00 43.36 (2) 1.61 1.16 1.69 1.53 2.55 2.12 2.25 1.74 1.56 1.92 3.47 5.93 4.83 5.17 3.90 1.92 0.00 43.36 8-12 57 14 132 144 193 115 82 55 36 103 186 155 195 340 240 54 0 2101 (1) 0.65 0.16 1.51 1.65 2.21 1.32 0.94 0.63 0.41 1.18 2.13 1.77 2.23 3.89 2.75 0.62 0.00 24.04 (2) 0.65 0.16 1.51 1.65 2.21 1.32 0.94 0.63 0.41 1.18 2.13 1.77 2.23 3.89 2.75 0.62 0.00 24.04 13-18 1 5 29 18 18 10 6 7 7 5 7 4 14 137 111 3 0 382 (1) 0.01 0.06 0.33 0.21 0.21 0.11 0.07 0.08 0.08 0.06 0.08 0.05 0.16 1.57 1.27 0.03 0.00 4.37 (2) 0.01 0.06 0.33 0.21 0.21 0.11 0.07 0.08 0.08 0.06 0.08 0.05 0.16 1.57 1.27 0.03 0.00 4.37 19-24 0 1 3 8 19 3 0 0 0 0 0 0 0 14 13 0 0 61 (1) 0.00 0.01 0.03 0.09 0.22 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.16 0.15 0.00 0.00 0.70 (2) 0.00 0.01 0.03 0.09 0.22 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.16 0.15 0.00 0.00 0.70 GT 24 0 0 0 4 15 0 0 0 0 1 0 0 0 1 0 0 0 21 (1) 0.00 0.00 0.00 0.05 0.17 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.24 (2) 0.00 0.00 0.00 0.05 0.17 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.24 ALL SPEEDS 283 194 382 400 534 353 331 281 260 378 665 908 1079 1382 956 353 0 8739 (1) 3.24 2.22 4.37 4.58 6.11 4.04 3.79 3.22 2.98 4.33 7.61 10.39 12.35 15.81 10.94 4.04 0.00 100.00 (2) 3.24 2.22 4.37 4.58 6.11 4.04 3.79 3.22 2.98 4.33 7.61 10.39 12.35 15.81 10.94 4.04 0.00 100.00 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS A CLASS FREQUENCY (PERCENT) = 33.51 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 1 1 0 0 0 0 0 0 0 0 1 0 0 0 0 3 (1) 0.00 0.00 0.03 0.03 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.10 (2) 0.00 0.00 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.03 C-3 7 8 11 8 18 8 16 8 7 12 9 10 8 3 9 5 0 147 (1) 0.24 0.27 0.38 0.27 0.62 0.27 0.55 0.27 0.24 0.41 0.31 0.34 0.27 0.10 0.31 0.17 0.00 5.02 (2) 0.08 0.09 0.13 0.09 0.21 0.09 0.18 0.09 0.08 0.14 0.10 0.11 0.09 0.03 0.10 0.06 0.00 1.68 4-7 25 32 38 50 50 100 98 46 40 43 47 38 39 40 32 22 0 740 (1) 0.85 1.09 1.30 1.71 1.71 3.42 3.35 1.57 1.37 1.47 1.61 1.30 1.33 1.37 1.09 0.75 0.00 25.29 (2) 0.29 0.37 0.44 0.57 0.57 1.15 1.12 0.53 0.46 0.49 0.54 0.44 0.45 0.46 0.37 0.25 0.00 8.47 8-12 30 31 79 105 68 98 117 95 55 87 145 169 140 121 82 40 0 1462 (1) 1.03 1.06 2.70 3.59 2.32 3.35 4.00 3.25 1.88 2.97 4.96 5.78 4.78 4.14 2.80 1.37 0.00 49.97 (2) 0.34 0.36 0.90 1.20 0.78 1.12 1.34 1.09 0.63 1.00 1.66 1.94 1.60 1.39 0.94 0.46 0.00 16.74 13-18 0 2 30 19 11 4 21 46 13 29 92 86 62 46 56 21 0 538 (1) 0.00 0.07 1.03 0.65 0.38 0.14 0.72 1.57 0.44 0.99 3.14 2.94 2.12 1.57 1.91 0.72 0.00 18.39 (2) 0.00 0.02 0.34 0.22 0.13 0.05 0.24 0.53 0.15 0.33 1.05 0.98 0.71 0.53 0.64 0.24 0.00 6.16 19-24 0 0 2 0 0 0 0 9 4 1 0 4 7 3 2 2 0 34 (1) 0.00 0.00 0.07 0.00 0.00 0.00 0.00 0.31 0.14 0.03 0.00 0.14 0.24 0.10 0.07 0.07 0.00 1.16 (2) 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.10 0.05 0.01 0.00 0.05 0.08 0.03 0.02 0.02 0.00 0.39 GT 24 0 0 0 0 0 0 0 2 0 0 0 0 0 0 0 0 0 2 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.07 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.02 ALL SPEEDS 62 73 161 183 147 210 252 206 119 172 293 307 257 213 181 90 0 2926 (1) 2.12 2.49 5.50 6.25 5.02 7.18 8.61 7.04 4.07 5.88 10.01 10.49 8.78 7.28 6.19 3.08 0.00 100.00 (2) 0.71 0.84 1.84 2.10 1.68 2.40 2.89 2.36 1.36 1.97 3.36 3.52 2.94 2.44 2.07 1.03 0.00 33.51 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS B CLASS FREQUENCY (PERCENT) = 3.84 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 C-3 0 1 0 4 2 0 1 0 1 2 0 0 0 0 1 0 0 12 (1) 0.00 0.30 0.00 1.19 0.60 0.00 0.30 0.00 0.30 0.60 0.00 0.00 0.00 0.00 0.30 0.00 0.00 3.58 (2) 0.00 0.01 0.00 0.05 0.02 0.00 0.01 0.00 0.01 0.02 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.14 4-7 6 2 4 6 4 8 8 4 3 7 2 4 7 4 2 4 0 75 (1) 1.79 0.60 1.19 1.79 1.19 2.39 2.39 1.19 0.90 2.09 0.60 1.19 2.09 1.19 0.60 1.19 0.00 22.39 (2) 0.07 0.02 0.05 0.07 0.05 0.09 0.09 0.05 0.03 0.08 0.02 0.05 0.08 0.05 0.02 0.05 0.00 0.86 8-12 5 5 6 8 12 10 6 6 6 7 12 20 19 14 8 5 0 149 (1) 1.49 1.49 1.79 2.39 3.58 2.99 1.79 1.79 1.79 2.09 3.58 5.97 5.67 4.18 2.39 1.49 0.00 44.48 (2) 0.06 0.06 0.07 0.09 0.14 0.11 0.07 0.07 0.07 0.08 0.14 0.23 0.22 0.16 0.09 0.06 0.00 1.71 13-18 0 0 3 1 4 1 2 6 1 1 2 14 11 13 15 4 0 78 (1) 0.00 0.00 0.90 0.30 1.19 0.30 0.60 1.79 0.30 0.30 0.60 4.18 3.28 3.88 4.48 1.19 0.00 23.28 (2) 0.00 0.00 0.03 0.01 0.05 0.01 0.02 0.07 0.01 0.01 0.02 0.16 0.13 0.15 0.17 0.05 0.00 0.89 19-24 0 0 2 0 0 0 0 1 0 0 0 0 2 5 6 0 0 16 (1) 0.00 0.00 0.60 0.00 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.00 0.60 1.49 1.79 0.00 0.00 4.78 (2) 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.02 0.06 0.07 0.00 0.00 0.18 GT 24 0 0 0 0 0 0 0 0 0 1 0 0 0 3 1 0 0 5 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.30 0.00 0.00 0.00 0.90 0.30 0.00 0.00 1.49 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.03 0.01 0.00 0.00 0.06 ALL SPEEDS 11 8 15 19 22 19 17 17 11 18 16 38 39 39 33 13 0 335 (1) 3.28 2.39 4.48 5.67 6.57 5.67 5.07 5.07 3.28 5.37 4.78 11.34 11.64 11.64 9.85 3.88 0.00 100.00 (2) 0.13 0.09 0.17 0.22 0.25 0.22 0.19 0.19 0.13 0.21 0.18 0.44 0.45 0.45 0.38 0.15 0.00 3.84 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS C CLASS FREQUENCY (PERCENT) = 5.39 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 C-3 3 4 0 0 1 0 0 0 1 0 1 1 1 3 1 0 0 16 (1) 0.64 0.85 0.00 0.00 0.21 0.00 0.00 0.00 0.21 0.00 0.21 0.21 0.21 0.64 0.21 0.00 0.00 3.40 (2) 0.03 0.05 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.01 0.01 0.01 0.03 0.01 0.00 0.00 0.18 4-7 6 5 4 7 10 4 8 1 7 9 7 9 8 4 8 6 0 103 (1) 1.27 1.06 0.85 1.49 2.12 0.85 1.70 0.21 1.49 1.91 1.49 1.91 1.70 0.85 1.70 1.27 0.00 21.87 (2) 0.07 0.06 0.05 0.08 0.11 0.05 0.09 0.01 0.08 0.10 0.08 0.10 0.09 0.05 0.09 0.07 0.00 1.18 8-12 18 6 8 11 11 10 11 10 9 6 10 18 27 17 16 3 0 191 (1) 3.82 1.27 1.70 2.34 2.34 2.12 2.34 2.12 1.91 1.27 2.12 3.82 5.73 3.61 3.40 0.64 0.00 40.55 (2) 0.21 0.07 0.09 0.13 0.13 0.11 0.13 0.11 0.10 0.07 0.11 0.21 0.31 0.19 0.18 0.03 0.00 2.19 13-18 5 4 5 0 1 0 3 6 2 0 6 4 17 33 25 5 0 116 (1) 1.06 0.85 1.06 0.00 0.21 0.00 0.64 1.27 0.42 0.00 1.27 0.85 3.61 7.01 5.31 1.06 0.00 24.63 (2) 0.06 0.05 0.06 0.00 0.01 0.00 0.03 0.07 0.02 0.00 0.07 0.05 0.19 0.38 0.29 0.06 0.00 1.33 19-24 1 0 0 0 2 0 0 0 1 0 1 2 2 12 18 0 0 39 (1) 0.21 0.00 0.00 0.00 0.42 0.00 0.00 0.00 0.21 0.00 0.21 0.42 0.42 2.55 3.82 0.00 0.00 8.28 (2) 0.01 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.01 0.00 0.01 0.02 0.02 0.14 0.21 0.00 0.00 0.45 GT 24 0 0 0 0 1 0 0 0 0 0 0 0 0 4 1 0 0 6 (1) 0.00 0.00 0.00 0.00 0.21 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.85 0.21 0.00 0.00 1.27 (2) 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.05 0.01 0.00 0.00 0.07 ALL SPEEDS 33 19 17 18 26 14 22 17 20 15 25 34 55 73 69 14 0 471 (1) 7.01 4.03 3.61 3.82 5.52 2.97 4.67 3.61 4.25 3.18 5.31 7.22 11.68 15.50 14.65 2.97 0.00 100.00 (2) 0.38 0.22 0.19 0.21 0.30 0.16 0.25 0.19 0.23 0.17 0.29 0.39 0.63 0.84 0.79 0.16 0.00 5.39 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS D CLASS FREQUENCY (PERCENT) = 31.84 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 2 0 0 0 0 0 0 0 0 0 0 0 0 0 0 1 0 3 (1) 0.07 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.04 0.00 0.11 (2) 0.02 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.03 C-3 12 5 8 4 8 6 10 6 7 4 7 5 2 6 12 8 0 110 (1) 0.43 0.18 0.29 0.14 0.29 0.22 0.36 0.22 0.25 0.14 0.25 0.18 0.07 0.22 0.43 0.29 0.00 3.96 (2) 0.14 0.06 0.09 0.05 0.09 0.07 0.11 0.07 0.08 0.05 0.08 0.06 0.02 0.07 0.14 0.09 0.00 1.26 4-7 63 37 13 19 22 43 36 16 23 42 43 26 36 26 47 35 0 527 (1) 2.27 1.33 0.47 0.68 0.79 1.55 1.29 0.58 0.83 1.51 1.55 0.94 1.29 0.94 1.69 1.26 0.00 18.96 (2) 0.72 0.42 0.15 0.22 0.25 0.49 0.41 0.18 0.26 0.48 0.49 0.30 0.41 0.30 0.54 0.40 0.00 6.04 8-12 99 85 25 49 35 35 16 43 53 52 66 94 90 119 137 66 0 1064 (1) 3.56 3.06 0.90 1.76 1.26 1.26 0.58 1.55 1.91 1.87 2.37 3.38 3.24 4.28 4.93 2.37 0.00 38.27 (2) 1.13 0.97 0.29 0.56 0.40 0.40 0.18 0.49 0.61 0.60 0.76 1.08 1.03 1.36 1.57 0.76 0.00 12.19 13-18 41 36 22 29 15 10 9 8 25 21 27 56 98 166 172 34 0 769 (1) 1.47 1.29 0.79 1.04 0.54 0.36 0.32 0.29 0.90 0.76 0.97 2.01 3.53 5.97 6.19 1.22 0.00 27.66 (2) 0.47 0.41 0.25 0.33 0.17 0.11 0.10 0.09 0.29 0.24 0.31 0.64 1.12 1.90 1.97 0.39 0.00 8.81 19-24 2 3 7 12 13 8 6 3 1 0 2 6 16 47 73 6 0 205 (1) 0.07 0.11 0.25 0.43 0.47 0.29 0.22 0.11 0.04 0.00 0.07 0.22 0.58 1.69 2.63 0.22 0.00 7.37 (2) 0.02 0.03 0.08 0.14 0.15 0.09 0.07 0.03 0.01 0.00 0.02 0.07 0.18 0.54 0.84 0.07 0.00 2.35 GT 24 1 3 3 11 30 10 5 1 1 0 1 0 0 12 24 0 0 102 (1) 0.04 0.11 0.11 0.40 1.08 0.36 0.18 0.04 0.04 0.00 0.04 0.00 0.00 0.43 0.86 0.00 0.00 3.67 (2) 0.01 0.03 0.03 0.13 0.34 0.11 0.06 0.01 0.01 0.00 0.01 0.00 0.00 0.14 0.27 0.00 0.00 1.17 ALL SPEEDS 220 169 78 124 123 112 82 77 110 119 146 187 242 376 465 150 0 2780 (1) 7.91 6.08 2.81 4.46 4.42 4.03 2.95 2.77 3.96 4.28 5.25 6.73 8.71 13.53 16.73 5.40 0.00 100.00 (2) 2.52 1.94 0.89 1.42 1.41 1.28 0.94 0.88 1.26 1.36 1.67 2.14 2.77 4.31 5.33 1.72 0.00 31.84 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS E CLASS FREQUENCY (PERCENT) = 14.77 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 0 1 0 0 0 1 0 0 0 0 3 0 0 0 0 5 (1) 0.00 0.00 0.00 0.08 0.00 0.00 0.00 0.08 0.00 0.00 0.00 0.00 0.23 0.00 0.00 0.00 0.00 0.39 (2) 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.03 0.00 0.00 0.00 0.00 0.06 C-3 1 8 7 10 4 7 9 6 4 6 3 2 3 2 3 2 0 77 (1) 0.08 0.62 0.54 0.78 0.31 0.54 0.70 0.47 0.31 0.47 0.23 0.16 0.23 0.16 0.23 0.16 0.00 5.97 (2) 0.01 0.09 0.08 0.11 0.05 0.08 0.10 0.07 0.05 0.07 0.03 0.02 0.03 0.02 0.03 0.02 0.00 0.88 4-7 19 22 14 16 8 12 19 20 16 20 26 27 27 25 22 21 0 314 (1) 1.47 1.71 1.09 1.24 0.62 0.93 1.47 1.55 1.24 1.55 2.02 2.09 2.09 1.94 1.71 1.63 0.00 24.34 (2) 0.22 0.25 0.16 0.18 0.09 0.14 0.22 0.23 0.18 0.23 0.30 0.31 0.31 0.29 0.25 0.24 0.00 3.60 8-12 35 25 8 3 9 9 6 16 19 23 56 102 97 109 131 41 0 689 (1) 2.71 1.94 0.62 0.23 0.70 0.70 0.47 1.24 1.47 1.78 4.34 7.91 7.52 8.45 10.16 3.18 0.00 53.41 (2) 0.40 0.29 0.09 0.03 0.10 0.10 0.07 0.18 0.22 0.26 0.64 1.17 1.11 1.25 1.50 0.47 0.00 7.89 13-18 7 3 1 5 1 0 2 4 1 1 20 59 28 23 37 6 0 198 (1) 0.54 0.23 0.08 0.39 0.08 0.00 0.16 0.31 0.08 0.08 1.55 4.57 2.17 1.78 2.87 0.47 0.00 15.35 (2) 0.08 0.03 0.01 0.06 0.01 0.00 0.02 0.05 0.01 0.01 0.23 0.68 0.32 0.26 0.42 0.07 0.00 2.27 19-24 0 0 0 0 3 0 2 0 0 0 0 2 0 0 0 0 0 7 (1) 0.00 0.00 0.00 0.00 0.23 0.00 0.16 0.00 0.00 0.00 0.00 0.16 0.00 0.00 0.00 0.00 0.00 0.54 (2) 0.00 0.00 0.00 0.00 0.03 0.00 0.02 0.00 0.00 0.00 0.00 0.02 0.00 0.00 0.00 0.00 0.00 0.08 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 62 58 30 35 25 28 38 47 40 50 105 192 158 159 193 70 0 1290 (1) 4.81 4.50 2.33 2.71 1.94 2.17 2.95 3.64 3.10 3.88 8.14 14.88 12.25 12.33 14.96 5.43 0.00 100.00 (2) 0.71 0.66 0.34 0.40 0.29 0.32 0.44 0.54 0.46 0.57 1.20 2.20 1.81 1.82 2.21 0.80 0.00 14.77 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS F CLASS FREQUENCY (PERCENT) = 5.99 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 C-3 7 2 3 4 2 1 4 5 4 6 4 3 7 4 2 5 0 63 (1) 1.34 0.38 0.57 0.76 0.38 0.19 0.76 0.96 0.76 1.15 0.76 0.57 1.34 0.76 0.38 0.96 0.00 12.05 (2) 0.08 0.02 0.03 0.05 0.02 0.01 0.05 0.06 0.05 0.07 0.05 0.03 0.08 0.05 0.02 0.06 0.00 0.72 4-7 6 16 10 10 5 3 8 12 9 18 17 16 13 12 17 10 0 182 (1) 1.15 3.06 1.91 1.91 0.96 0.57 1.53 2.29 1.72 3.44 3.25 3.06 2.49 2.29 3.25 1.91 0.00 34.80 (2) 0.07 0.18 0.11 0.11 0.06 0.03 0.09 0.14 0.10 0.21 0.19 0.18 0.15 0.14 0.19 0.11 0.00 2.08 8-12 24 3 3 1 0 1 1 3 4 8 14 29 41 34 41 30 0 237 (1) 4.59 0.57 0.57 0.19 0.00 0.19 0.19 0.57 0.76 1.53 2.68 5.54 7.84 6.50 7.84 5.74 0.00 45.32 (2) 0.27 0.03 0.03 0.01 0.00 0.01 0.01 0.03 0.05 0.09 0.16 0.33 0.47 0.39 0.47 0.34 0.00 2.71 13-18 3 0 0 0 0 1 0 1 0 0 0 8 11 4 7 6 0 41 (1) 0.57 0.00 0.00 0.00 0.00 0.19 0.00 0.19 0.00 0.00 0.00 1.53 2.10 0.76 1.34 1.15 0.00 7.84 (2) 0.03 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.00 0.09 0.13 0.05 0.08 0.07 0.00 0.47 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 40 21 16 15 7 6 13 21 17 32 35 56 72 54 67 51 0 523 (1) 7.65 4.02 3.06 2.87 1.34 1.15 2.49 4.02 3.25 6.12 6.69 10.71 13.77 10.33 12.81 9.75 0.00 100.00 (2) 0.46 0.24 0.18 0.17 0.08 0.07 0.15 0.24 0.19 0.37 0.40 0.64 0.82 0.62 0.77 0.58 0.00 5.99 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS G CLASS FREQUENCY (PERCENT) = 4.66 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 0 1 1 0 0 0 0 0 0 0 1 0 1 0 0 2 0 6 (1) 0.00 0.25 0.25 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.25 0.00 0.25 0.00 0.00 0.49 0.00 1.47 (2) 0.00 0.01 0.01 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.01 0.00 0.00 0.02 0.00 0.07 C-3 3 2 6 1 1 1 2 4 2 6 4 7 6 3 4 1 0 53 (1) 0.74 0.49 1.47 0.25 0.25 0.25 0.49 0.98 0.49 1.47 0.98 1.72 1.47 0.74 0.98 0.25 0.00 13.02 (2) 0.03 0.02 0.07 0.01 0.01 0.01 0.02 0.05 0.02 0.07 0.05 0.08 0.07 0.03 0.05 0.01 0.00 0.61 4-7 9 6 4 0 1 4 3 6 10 17 16 24 18 13 13 8 0 152 (1) 2.21 1.47 0.98 0.00 0.25 0.98 0.74 1.47 2.46 4.18 3.93 5.90 4.42 3.19 3.19 1.97 0.00 37.35 (2) 0.10 0.07 0.05 0.00 0.01 0.05 0.03 0.07 0.11 0.19 0.18 0.27 0.21 0.15 0.15 0.09 0.00 1.74 8-12 18 6 4 0 0 1 1 5 5 12 13 16 30 20 26 25 0 182 (1) 4.42 1.47 0.98 0.00 0.00 0.25 0.25 1.23 1.23 2.95 3.19 3.93 7.37 4.91 6.39 6.14 0.00 44.72 (2) 0.21 0.07 0.05 0.00 0.00 0.01 0.01 0.06 0.06 0.14 0.15 0.18 0.34 0.23 0.30 0.29 0.00 2.08 13-18 4 0 0 0 0 0 0 1 0 0 0 0 3 0 4 2 0 14 (1) 0.98 0.00 0.00 0.00 0.00 0.00 0.00 0.25 0.00 0.00 0.00 0.00 0.74 0.00 0.98 0.49 0.00 3.44 (2) 0.05 0.00 0.00 0.00 0.00 0.00 0.00 0.01 0.00 0.00 0.00 0.00 0.03 0.00 0.05 0.02 0.00 0.16 19-24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 GT 24 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 0 (1) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 (2) 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 0.00 ALL SPEEDS 34 15 15 1 2 6 6 16 17 35 34 47 58 36 47 38 0 407 (1) 8.35 3.69 3.69 0.25 0.49 1.47 1.47 3.93 4.18 8.60 8.35 11.55 14.25 8.85 11.55 9.34 0.00 100.00 (2) 0.39 0.17 0.17 0.01 0.02 0.07 0.07 0.18 0.19 0.40 0.39 0.54 0.66 0.41 0.54 0.44 0.00 4.66 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

SEABROOK JAN24-DEC24 MET DATA JOINT FREQUENCY DISTRIBUTION (210-FOOT TOWER) 209.0 FT WIND DATA STABILITY CLASS ALL CLASS FREQUENCY (PERCENT) = 100.00 WIND DIRECTION FROM SPEED N NNE NE ENE E ESE SE SSE S SSW SW WSW W WNW NW NNW VRBL TOTAL MPH CALM 2 1 2 2 0 0 0 1 0 0 1 0 5 0 0 3 0 17 (1) 0.02 0.01 0.02 0.02 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.00 0.06 0.00 0.00 0.03 0.00 0.19 (2) 0.02 0.01 0.02 0.02 0.00 0.00 0.00 0.01 0.00 0.00 0.01 0.00 0.06 0.00 0.00 0.03 0.00 0.19 C-3 33 30 35 31 36 23 42 29 26 36 28 28 27 21 32 21 0 478 (1) 0.38 0.34 0.40 0.36 0.41 0.26 0.48 0.33 0.30 0.41 0.32 0.32 0.31 0.24 0.37 0.24 0.00 5.47 (2) 0.38 0.34 0.40 0.36 0.41 0.26 0.48 0.33 0.30 0.41 0.32 0.32 0.31 0.24 0.37 0.24 0.00 5.47 4-7 134 120 87 108 100 174 180 105 108 156 158 144 148 124 141 106 0 2093 (1) 1.53 1.37 1.00 1.24 1.15 1.99 2.06 1.20 1.24 1.79 1.81 1.65 1.69 1.42 1.61 1.21 0.00 23.97 (2) 1.53 1.37 1.00 1.24 1.15 1.99 2.06 1.20 1.24 1.79 1.81 1.65 1.69 1.42 1.61 1.21 0.00 23.97 8-12 229 161 133 177 135 164 158 178 151 195 316 448 444 434 441 210 0 3974 (1) 2.62 1.84 1.52 2.03 1.55 1.88 1.81 2.04 1.73 2.23 3.62 5.13 5.08 4.97 5.05 2.40 0.00 45.51 (2) 2.62 1.84 1.52 2.03 1.55 1.88 1.81 2.04 1.73 2.23 3.62 5.13 5.08 4.97 5.05 2.40 0.00 45.51 13-18 60 45 61 54 32 16 37 72 42 52 147 227 230 285 316 78 0 1754 (1) 0.69 0.52 0.70 0.62 0.37 0.18 0.42 0.82 0.48 0.60 1.68 2.60 2.63 3.26 3.62 0.89 0.00 20.09 (2) 0.69 0.52 0.70 0.62 0.37 0.18 0.42 0.82 0.48 0.60 1.68 2.60 2.63 3.26 3.62 0.89 0.00 20.09 19-24 3 3 11 12 18 8 8 13 6 1 3 14 27 67 99 8 0 301 (1) 0.03 0.03 0.13 0.14 0.21 0.09 0.09 0.15 0.07 0.01 0.03 0.16 0.31 0.77 1.13 0.09 0.00 3.45 (2) 0.03 0.03 0.13 0.14 0.21 0.09 0.09 0.15 0.07 0.01 0.03 0.16 0.31 0.77 1.13 0.09 0.00 3.45 GT 24 1 3 3 11 31 10 5 3 1 1 1 0 0 19 26 0 0 115 (1) 0.01 0.03 0.03 0.13 0.36 0.11 0.06 0.03 0.01 0.01 0.01 0.00 0.00 0.22 0.30 0.00 0.00 1.32 (2) 0.01 0.03 0.03 0.13 0.36 0.11 0.06 0.03 0.01 0.01 0.01 0.00 0.00 0.22 0.30 0.00 0.00 1.32 ALL SPEEDS 462 363 332 395 352 395 430 401 334 441 654 861 881 950 1055 426 0 8732 (1) 5.29 4.16 3.80 4.52 4.03 4.52 4.92 4.59 3.83 5.05 7.49 9.86 10.09 10.88 12.08 4.88 0.00 100.00 (2) 5.29 4.16 3.80 4.52 4.03 4.52 4.92 4.59 3.83 5.05 7.49 9.86 10.09 10.88 12.08 4.88 0.00 100.00 (1)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PAGE (2)=PERCENT OF ALL GOOD OBSERVATIONS FOR THIS PERIOD C= CALM (WIND SPEED LESS THAN OR EQUAL TO 0.95 MPH)

L-2025-096, 2024 Annual Radioactive Effluent Release Report

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L-2025-096, 2024 Annual Radioactive Effluent Release Report

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