Text

Annual Radioactive Effluent Release Report for 2024 Monitoring Period
	ML25113A037
Person / Time
Site:	Sequoyah
Issue date:	04/23/2025
From:	Marshall T; Tennessee Valley Authority
To:	; Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk
References
	Download: ML25113A037 (1)
	v • d • e

Sequoyah Nuclear Plant, Post Office Box 2000, Soddy Daisy, Tennessee 37384 April 23, 2025 10 CFR 50.4 10 CFR 50.36a 10 CFR 50, Appendix I 10 CFR 72.44(d)(3)

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Sequoyah Nuclear Plant, Units 1 and 2 Renewed Facility Operating License Nos. DPR-77 and DPR-79 NRC Docket Nos. 50-327, 50-328, and 72-034

Subject:

Annual Radioactive Effluent Release Report for 2024 Monitoring Period Enclosed is the Annual Radioactive Effluent Release Report (ARERR) for the period of January 1 to December 31, 2024. This report (Enclosure) is being submitted in accordance with the respective Sequoyah Nuclear Plant (SQN), Units 1 and 2, Technical Specification (TS) 5.6.2 and Certificate of Compliance for Spent Fuel Storage Casks Nos. 1014 and 1032, Chapter 5.

Offsite Dose Calculation Manual (ODCM), Section 5.2 requires that a Radiological Impact Assessment be submitted with the ARERR for the same reporting period. The assessment is included in the report. There were no changes to the ODCM during the reporting period.

There are no new regulatory commitments contained in this letter. If you have any questions concerning this matter, please contact Mr. Rick Medina, Site Compliance Manager, at (423) 843-8129 or rmedina4@tva.gov.

Respectfully, Thomas Marshall Site Vice President Sequoyah Nuclear Plant

Enclosure:

Annual Radioactive Effluent Release Report, Sequoyah Nuclear Plant, January -

December 2024

U.S. Nuclear Regulatory Commission Page 2 April 23, 2025 cc (Enclosure):

NRC Regional Administrator - Region II NRC Senior Resident Inspector - Sequoyah Nuclear Plant NRR Project Manager - Sequoyah Nuclear Plant

ENCLOSURE ANNUAL RADIOACTIVE EFFLUENT RELEASE REPORT SEQUOYAH NUCLEAR PLANT JANUARY - DECEMBER 2024

1 Sequoyah Nuclear Power Plant Tennessee Valley Authority Annual Radioactive Effluent Release Report 2024

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 2

I.

Introduction..........................................................................................................................................5 II.

Supplemental Information....................................................................................................................5 A.

Regulatory Limits.............................................................................................................................5 B.

Limitation on Dose Rate...................................................................................................................6 C.

Average Energy................................................................................................................................6 D.

Measurements & Approximations of Total Radioactivity................................................................6 E.

Batch Releases.................................................................................................................................8 F.

Abnormal Releases........................................................................................................................13 G.

Non-routine, Planned Discharges..................................................................................................13 H.

Radioactive Waste System Treatment Changes............................................................................13 I.

Land Use Census Changes.............................................................................................................. 13 J.

Effluent Monitoring Instrument Inoperability > 30 Days............................................................... 13 K.

Effluent Monitoring Equipment Sample Deviation........................................................................ 13 L.

Offsite Dose Calculation Manual Changes..................................................................................... 13 M.

Groundwater Monitoring and Program (NEI 07-07)...................................................................... 14 N.

Errata/Corrections to Previous ARERRs......................................................................................... 16 III.

Gaseous Effluents.......................................................................................................................... 17 Table 1-A Gaseous Effluents - Summation of all Releases...................................................................... 17 Table 1-B Gaseous Effluents - Ground Level Releases (Batch)............................................................... 18 Zeroes indicate that no radioactivity was present at detectable levels................................................. 18 Table 1-B Gaseous Effluents - Ground Level Releases (Continuous)..................................................... 18 IV.

Liquid Effluents.............................................................................................................................. 19 Table 2-A Liquid Effluents - Summation of all Releases..........................................................................19 Table 2-B Liquid Effluents - Batch Mode................................................................................................ 20 Table 2-B Liquid Effluents - Continuous Mode....................................................................................... 21 V.

Solid Waste Storage and Shipment..................................................................................................... 22 A.

Types of Solid Waste - Summary................................................................................................... 22 B.

Estimate of Major Nuclide Composition (by waste type).............................................................. 23 C.

Solid Waste Disposition................................................................................................................. 25 VI.

Independent Spent Fuel Storage Installation................................................................................ 26 VII.

Radiological Impact to Man........................................................................................................... 27 A.

Introduction................................................................................................................................... 27

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 3

B.

Dose Limits.....................................................................................................................................27 C.

Dose Calculations...........................................................................................................................27 D.

Doses from Airborne Effluents......................................................................................................28 E.

Doses from Liquid Effluents...........................................................................................................29 F.

Population Doses...........................................................................................................................30 G.

Offsite Direct Radiation Dose.........................................................................................................30 H.

Dose to a Member of the Public Inside the Site Boundary............................................................30 I.

Total Dose......................................................................................................................................31 J.

Tables.............................................................................................................................................32 Table 3-A Doses from Airborne Effluents - 1st Quarter..........................................................................32 Table 3-B Doses from Airborne Effluents - 2nd Quarter.........................................................................33 Table 3-C Doses from Airborne Effluents - 3rd Quarter.......................................................................... 34 Table 3-D Doses from Airborne Effluents - 4th Quarter..........................................................................35 Table 4-A Doses from Liquid Effluents - 1st Quarter............................................................................... 36 Table 4-B Doses from Liquid Effluents - 2nd Quarter.............................................................................. 36 Table 4-C Doses from Liquid Effluents - 3rd Quarter.............................................................................. 37 Table 4-D Doses from Liquid Effluents - 4th Quarter.............................................................................. 37 Table 5 Total Dose from Fuel Cycle......................................................................................................... 38 VIII.

Meteorological Data...................................................................................................................... 39

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 4

TABLE 1-A GASEOUS EFFLUENTS - SUMMATION OF ALL RELEASES..............................................................................................17 TABLE 1-B GASEOUS EFFLUENTS - GROUND LEVEL RELEASES (BATCH).......................................................................................18 TABLE 1-B GASEOUS EFFLUENTS - GROUND LEVEL RELEASES (CONTINUOUS).............................................................................. 18 TABLE 2-A LIQUID EFFLUENTS - SUMMATION OF ALL RELEASES................................................................................................. 19 TABLE 2-B LIQUID EFFLUENTS - BATCH MODE...................................................................................................................... 20 TABLE 2-B LIQUID EFFLUENTS - CONTINUOUS MODE.............................................................................................................21 TABLE 3-A DOSES FROM AIRBORNE EFFLUENTS - 1ST QUARTER................................................................................................. 32 TABLE 3-B DOSES FROM AIRBORNE EFFLUENTS - 2ND QUARTER................................................................................................ 33 TABLE 3-C DOSES FROM AIRBORNE EFFLUENTS - 3RD QUARTER................................................................................................ 34 TABLE 3-D DOSES FROM AIRBORNE EFFLUENTS - 4TH QUARTER................................................................................................35 TABLE 4-A DOSES FROM LIQUID EFFLUENTS - 1ST QUARTER.....................................................................................................36 TABLE 4-B DOSES FROM LIQUID EFFLUENTS - 2ND QUARTER..................................................................................................... 36 TABLE 4-C DOSES FROM LIQUID EFFLUENTS - 3RD QUARTER..................................................................................................... 37 TABLE 4-D DOSES FROM LIQUID EFFLUENTS - 4TH QUARTER..................................................................................................... 37 TABLE 5 TOTAL DOSE FROM FUEL CYCLE............................................................................................................................... 38 TABLES

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 5

I.

Introduction The Annual Radioactive Effluent Release Report covering the operation of both units is submitted pursuant to Sequoyah Nuclear Plant Technical Specification 5.6.2 and Offsite Dose Calculation Manual 5.2.

II.

Supplemental Information A. Regulatory Limits

1. Gaseous Effluents Dose rates due to radioactivity released in gaseous effluents from the site to areas at and beyond the unrestricted area boundary shall be limited to the following:

Noble gases:

Less than or equal to 500 mrem/year to the total body.

Less than or equal to 3000 mrem/year to the skin.

Iodines, tritium and particulates with half-lives greater than eight days Less than or equal to 1500 mrem/year to any organ.

Dose to a member of the public due to Iodines, tritium and particulates with half-lives greater than eight days Less than or equal to 7.5 mrem to any organ during any calendar quarter.

Less than or equal to 15 mrem to any organ during any calendar year.

Air dose due to noble gases Less than or equal to 5 mrad for gamma radiation and less than or equal to 10 mrad for beta radiation during any calendar quarter.

Less than or equal to 10 mrad for gamma radiation and less than or equal to 20 mrad for beta radiation during any calendar year.

2. Liquid Effluents The annual average concentration of radioactivity released in liquid effluents to unrestricted areas shall be limited to the concentrations specified in Title 10 of the Code of Federal Regulations (CFR), Part 20 (Standards for Protection against Radiation),

Appendix B, Table 2, Column 2, for radionuclides other than dissolved or entrained noble gases. For dissolved or entrained noble gases, the concentration shall be limited to 2.0E-04 microcuries/milliliter The dose or dose commitment to a member of the public from radioactivity in liquid effluents released to unrestricted areas shall be limited to less than or equal to 1.5 mrem to the total body during any calendar quarter, less than or equal to 5 mrem to any organ during any calendar quarter, less than or equal to 3 mrem to the total body during any calendar year and less than or equal to 10 mrem to any organ during any calendar year.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 6

B. Limitation on Dose Rate

1. Gaseous Effluents Concentration limits for gaseous releases are met through compliance with the maximum permissible dose rates for gaseous releases as defined in plant Offsite Dose Calculation Manual (ODCM). (These values are used as applicable limits for gaseous effluents.)

Noble gases:

Less than or equal to 500 mrem/year to the total body.

Less than or equal to 3000 mrem/year to the skin.

Iodines, tritium and particulates with half-lives greater than eight days Less than or equal to 1500 mrem/year to any organ.

2. Liquid Effluents The effluent concentration limits (ECL) for liquids are those listed in 10 CFR 20, Appendix B, Table 2, Column 2. For dissolved and entrained gases, the ECL of 2.0E-04

-135 concentration in air (submersion dose) converted to an equivalent concentration in water as discussed in the International Commission on Radiological Protection (ICRP), Publication 2. (These values are used as applicable limits for liquid effluents.)

C. Average Energy Sequoyah Nuclear Plant's ODCM limits the dose equivalent rates due to the release of noble gases to less than or equal to 500 mrem/year to the total body and less than or equal to 3000 mrem/year to the skin. The use of dose rates is in accordance with NUREG-0133, "Preparation of Radiological Effluent Technical Specifications for Nuclear Power Plants." Since the release rate is not used for effluent control, the average energy discussed in Regulatory Guide 1.21 (used for release rate control) is not included in this report.

D. Measurements & Approximations of Total Radioactivity Radioactivity measurements performed in support of the Sequoyah Nuclear Plant ODCM meet the Lower Limit of Detection requirements given in ODCM Tables 2.2-1 and 2.2-2.

1. Gaseous Effluents Fission and Activation Gases Airborne effluent gaseous activity is continuously monitored and recorded. Additional grab samples from the shield building, auxiliary building, service building and condenser vacuum exhausts are taken and analyzed at least monthly to determine the quantity of noble gas activity released for the month based on the average vent flow rates recorded for the sample period. Also, noble gas samples are collected and evaluated for the shield and auxiliary buildings following startup, shutdown or rated thermal power change exceeding 15 percent within one hour (Sampling is only required if the dose equivalent I-131 concentration in the primary coolant or the noble gas activity monitor shows that the containment activity has increased more than a factor of 3).

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 7

The quantity of noble gases released through the shield and auxiliary building exhausts due to purging or venting of containment and releases of waste gas decay tanks are also determined.

The total noble gas activity released for the month is then determined by summing of the activity released from each vent for the sampling periods.

Iodines and Particulates in Gaseous Releases lodine and particulate activity is continuously sampled. Charcoal and particulate samples are taken from the shield and auxiliary building exhausts and analyzed at least weekly to determine the total activity released from the plant based on the average vent flow rates recorded for the sampling period.

Also, particulate and charcoal samples are taken from the shield and auxiliary building exhausts within 24 hours2.777778e-4 days 0.00667 hours 3.968254e-5 weeks 9.132e-6 months following startup, shutdown, or a rated thermal power change exceeding 15 percent within one hour, and will be repeated for seven days if either dose equivalent I-131 concentration in the primary coolant or the noble gas activity monitor shows that containment activity has increased more than a factor of 3. The quantity of iodine and particulate released from each vent during each sampling period is then determined using the average vent flow rates recorded for the sampling period and activity concentration.

The total particulate and iodine activity released for the month is then determined by summing all activity released from the shield and auxiliary building exhausts for the sampling periods.

Carbon-14 in Gaseous Releases The Carbon-14 production and effluent source term estimates were based on EPRI methodology provided in EPRI Report 1021106, "Estimation of Carbon-14 in Nuclear Power Plant Gaseous Effluents," dated December 2010. It was determined that 21.6 curies of Carbon-14 is generated annually at Sequoyah Nuclear Plant. However, only 98%

is considered released as gas and only the carbon dioxide form (20%) of that is used in the gaseous dose calculations

2. Liquid Effluents Batch (Radwaste and during periods of primary to secondary leakage, condensate regenerants to cooling tower blowdown)

Total gamma isotopic activity concentrations are determined on each batch of liquid effluent prior to release. The total activity of a released batch is determined by summing each nuclide's concentration and multiplying by the total volume discharged. The total activity released during a month is then determined by summing the activity content of each batch discharged during the month.

Continuous Releases and Periodic Continuous Releases (Condensate regenerants, turbine building sump, and steam generator blowdown)

Total gamma isotopic activity and tritium concentrations are determined monthly on one composite sample each from the condensate system, and the turbine building sump.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 8

The tritium value is applied to releases over the month. Total gamma isotopic activity concentration for Units 1 and 2 steam generator blowdown is determined 3 times a week. In addition to ODCM Table 2.2-1, tritium concentrations are determined 3 times a week, averaged for the month, and applied to releases over the month. The total activity of the continuous release is determined by summing each nuclide's concentration and multiplying by the total volume discharged.

E. Batch Releases

1. Gaseous

2. Liquid Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total

1. Gaseous

1. Number of Batch Releases 40 33 25 15 113

2. Total duration of batch releases minutes 7.90E+04 3.94E+04 1.02E+05 1.68E+04 2.37E+05

3. Maximum batch release duration minutes 3.54E+04 5.30E+03 3.90E+04 1.47E+03 3.90E+04

4. Average batch release duration minutes 1.98E+03 1.20E+03 4.08E+03 1.12E+03 2.10E+03

5. Minimum batch release duration minutes 4.00E+01 2.71E+02 2.03E+02 1.77E+02 4.00E+01 Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total

1. Liquids

1. Number of Batch Releases 47 58 66 37 208

2. Total duration of batch releases minutes 7.59E+03 9.08E+03 1.02E+04 5.91E+03 3.28E+04

3. Maximum batch release duration minutes 1.97E+02 1.93E+02 2.00E+02 2.30E+02 2.30E+02

4. Average batch release duration minutes 1.62E+02 1.57E+02 1.54E+02 1.60E+02 1.57E+02

5. Minimum batch release duration minutes 1.26E+02 1.22E+02 8.50E+01 1.20E+02 8.50E+01

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 9

Release Type: Gaseous (Steam)

Release Point: Unit 1 Power Operated Relief Valves (PORV) 1, 2, 3, & 4 Dates of Release:

3/23/2024 1300 - 4/28/2024 0400 (U1R26) 8/23/2024 1100 - 9/24/2024 0500 (U1 Forced Outage) 9/29/2024 1900 - 10/17/2024 2100 (U1 Forced Outage)

This evaluation is for the release to the environment that occurred from U1 PORVs 1, 2, 3, and 4 during the U1R26 Refueling Outage, a U1 Forced Outage, and an additional U1 Forced Outage. Following the reactor trip, the Steam Generator PORVs were open for periods of time during each of the outages. The following is data used to determine the curies and dose impacts as a result of the releases:

The evaluation assumed the release was constant from PORVs 1, 2, 3, and 4 for each of the three events.

There have been no gamma emitting radionuclides identified in any Secondary Coolant samples during the previous cycle.

The first release occurred for 9 days in Q1 and 28 days in Q2 as a result of U1R26. Therefore 24%

of the total activity for Q1 and 76% of the total activity for Q2 were utilized for quarterly dose calculations.

The second release occurred for 33 days in Q3 as a result of the first U1 Forced Outage.

Therefore 100% of the total activity from this event is utilized for the quarterly dose calculation.

The third release occurred for 2 days in Q3 and 17 days in Q4 as a result of the second U1 Forced Outage. Therefore 11% of the total event activity for Q3 and 89% of the total event activity for Q4 were utilized for quarterly dose calculations.

The volume of the steam generator was taken from Westinghouse Guidelines for Secondary Water Chemistry. The listed normal water level value of 3516 ft3 was used as a conservative value. This calculation assumes that the total volume of the generators was released and that all the tritium present in that initial volume was released. The calculation for the total tritium activity released is as follows:

3516 ft3/generator

2.832E+04 ml/ft3

4 generators = 3.983E+08 ml U1R26: 1.41E-06 µCi/ml

3.983E+08 ml = 5.62E+02 µCi of H3 or 5.62E-04 Ci of H3 U1 Forced Outage: 2.62E-06 µCi/ml

3.983E+08 ml = 1.04E+03 µCi of H3 or 1.04E-03 Ci of H3 U1 Forced Outage: 1.62E-06 µCi/ml

3.983E+08 ml = 6.46E+02 µCi of H3 or 6.46E-04 Ci of H3 Q1 activity released: 0.24

5.62E-04 = 1.35E-04 Ci of H3 Q2 activity released: 0.76

5.62E-04 = 4.27E-04 Ci of H3 Q3 activity released: (1.00

1.04E-03 = 1.04E-03 Ci of H3) + (0.11*6.46E-04 = 7.10E-05 Ci of H3) = 1.11E-03 Ci of H3 Q4 activity released: 0.89

6.46E-04 = 5.75E-04 Ci of H3

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 10 Release Type: Gaseous (Steam)

Release Point: Unit 2 Power Operated Relief Valves (PORV) 1, 2, 3, & 4 Dates of Release: 7/21/2024 0700 - 12/31/2024 2359 (U2 Forced Outage)

This evaluation is for the release to the environment that occurred from Unit 2 PORVs 1, 2, 3 and 4 during the U2 Forced Outage. Following the reactor trip, the Steam Generator PORVs were open for periods of time during the outage. The following is data used to determine the curies and dose impacts as a result of the release:

The evaluation assumed the release was constant from PORVs 1, 2, 3, and 4.

There have been no gamma emitting radionuclides identified in any Secondary Coolant samples during the previous cycle.

The release occurred for 72 days in Q3 and 92 days in Q4 as a result of the U2 forced Outage.

Therefore 44% of the total activity for Q3 and 56% of the total activity for Q4 were utilized for quarterly dose calculations.

The volume of the steam generator was taken from Westinghouse Guidelines for Secondary Water Chemistry. The listed normal water level value of 3516 ft3 was used as a conservative value. This calculation assumes that the total volume of the generators was released and that all the tritium present in that initial volume was released. The calculation for the total tritium activity released is as follows:

3516 ft3/generator

2.832E+04 ml/ft3

4 generators = 3.983E+08 ml 2.59E-06 µCi/ml

3.983E+08 ml = 1.03E+03 µCi of H3 or 1.03E-03 Ci of H3 Q3 activity released: 0.44

1.03E-03 = 4.53E-04 Ci of H3 Q4 activity released: 0.56

1.03E-03 = 5.77E-04 Ci of H3 Combined Unit 1 and Unit 2 PORV Quarterly Contribution:

The activity of 1.35E-04 Ci H3 was added to the 1st Quarter section of Table 1-A Gaseous Effluents -

Summation of All Releases and Table 3-A Doses from Airborne Effluents - 1st Quarter.

The activity of 4.27E-04 Ci H3 was added to the 2nd Quarter section of Table 1-A Gaseous Effluents -

Summation of All Releases and Table 3-B Doses from Airborne Effluents - 2nd Quarter.

The activities of 1.1.1E-03 (U1) and 4.53E-04 (U2) Ci H3 were added to the 3rd Quarter section of Table 1-A Gaseous Effluents - Summation of All Releases and Table 3-C Doses from Airborne Effluents - 3rd Quarter.

The activities 5.75E-04 (U1) and 5.77E-04 (U2) Ci H3 were added to the 4th Quarter section of Table 1-A Gaseous Effluents - Summation of All Releases and Table 3-D Doses from Airborne Effluents - 4th Quarter.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 11 U1 PORV H-3 Individual Doses (Q1)

Pathway External Dose Quarterly Limit Percent of Limit Location Sector/Distance/Unit Gamma Air 0.00E+01 mrad 5 mrad

<1 N/A Beta Air 0.00E+01 mrad 10 mrad

<1 N/A Submersion Total Body 0.00E+01 mrad N/A N/A N/A Skin 0.00E+01 mrad N/A N/A N/A Organ Dose Child/Thyroid 6.43E-08 mrem 7.5 mrem

<1 WSW/1152/meters Child/Total Body 6.43E-08 mrem 7.5 mrem

<1 WSW/1152/meters Population Doses (Q1)

Total Body Dose 6.72E-07 man-rem Maximum Organ Dose (organ) 6.72E-07 man-rem (Thyroid, Liver, Bone, GIT, Lung, Kidney)

U1 PORV H-3 Individual Doses (Q2)

Pathway External Dose Quarterly Limit Percent of Limit Location Sector/Distance/Unit Gamma Air 0.00E+01 mrad 5 mrad

<1 N/A Beta Air 0.00E+01 mrad 10 mrad

<1 N/A Submersion Total Body 0.00E+01 mrad N/A N/A N/A Skin 0.00E+01 mrad N/A N/A N/A Organ Dose Child/Thyroid 1.47E-07 mrem 7.5 mrem

<1 WSW/1152/meters Child/Total Body 1.47E-07 mrem 7.5 mrem

<1 WSW/1152/meters Population Doses (Q2)

Total Body Dose 1.70E-06 man-rem Maximum Organ Dose (organ) 1.70E-06 man-rem (Thyroid, Liver, Bone, GIT, Lung, Kidney)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 12 U1 and U2 PORV H-3 Individual Doses (Q3)

Pathway External Dose Quarterly Limit Percent of Limit Location Sector/Distance/Unit Gamma Air 0.00E+01 mrad 5 mrad

<1 N/A Beta Air 0.00E+01 mrad 10 mrad

<1 N/A Submersion Total Body 0.00E+01 mrad N/A N/A N/A Skin 0.00E+01 mrad N/A N/A N/A Organ Dose Child/Thyroid 6.51E-07 mrem 7.5 mrem

<1 WSW/1152/meters Child/Total Body 6.51E-07 mrem 7.5 mrem

<1 WSW/1152/meters Population Doses (Q1)

Total Body Dose 8.33E-06 man-rem Maximum Organ Dose (organ) 8.33E-06 man-rem (Thyroid, Liver, Bone, GIT, Lung, Kidney)

U1 and U2 PORV H-3 Individual Doses (Q4)

Pathway External Dose Quarterly Limit Percent of Limit Location Sector/Distance/Unit Gamma Air 0.00E+01 mrad 5 mrad

<1 N/A Beta Air 0.00E+01 mrad 10 mrad

<1 N/A Submersion Total Body 0.00E+01 mrad N/A N/A N/A Skin 0.00E+01 mrad N/A N/A N/A Organ Dose Child/Thyroid 5.30E-07 mrem 7.5 mrem

<1 SSW/4363/meters Child/Total Body 5.30E-07 mrem 7.5 mrem

<1 SSW/4363/meters Population Doses (Q2)

Total Body Dose 7.12E-06 man-rem Maximum Organ Dose (organ) 7.12E-06 man-rem (Thyroid, Liver, Bone, GIT, Lung, Kidney)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 13 F. Abnormal Releases In calendar year 2024, there were no abnormal releases.

G. Non-routine, Planned Discharges In calendar year 2024, there were no non-routine planned discharges.

H. Radioactive Waste System Treatment Changes In calendar year 2024, there were no changes to the radwaste system or the process control program.

I. Land Use Census Changes In calendar year 2024, there were no changes to the land use census.

J. Effluent Monitoring Instrument Inoperability > 30 Days Date Description of Non Functionality 5/4/23 - 5/20/24 CR#1852508 0-RM-90-122, Liquid Radwaste Effluent Line Radiation Monitor, was declared non-functional on 5/4/23 due to a thermal dispersion flow switch failure (0-FS-90-122). ECP SQN-23-052 replaced the obsolete flow switch, and the radiation monitor was returned to service on 5/20/24. Compensatory sampling remained in place during the time of non-functionality.

12/1/23 - 2/21/24 CR#1895759 0-RM-90-118A, Waste Gas Disposal System Radiation Monitor, was declared non-functional on 12/1/23 due to faulty alarm circuitry. Corrective maintenance was performed and the radiation monitor returned to service on 2/21/24.

Compensatory sampling remained in place during the time of non-functionality.

1/13/24 - 7/3/24 CR#1902857 2-RM-90-400, U2 Shield Building Exhaust System Radiation Monitor, was declared non-functional on 1/13/24 due to flow element/controller failure (2-FE/FIC-90-452B). ECP SQN-23-005 replaced the obsolete flow element/controller, and the radiation monitor was returned to service on 7/3/24. Compensatory sampling remained in place during the time of non-functionality.

6/25/24 - TBD CR#1940231 1-RM-90-400, U1 Shield Building Exhaust System Radiation Monitor, was declared non-functional on 6/25/24 due to flow element/controller failure (1-FE/FIC-90-452A. ECP SQN-24-038 is in progress to replace the obsolete flow element/controller. Compensatory sampling has been in place and will continue until radiation monitor has returned to functional status.

K. Effluent Monitoring Equipment Sample Deviation In calendar year 2024 there were no effluent monitoring equipment sample deviations.

L. Offsite Dose Calculation Manual Changes In calendar year 2024 there were no changes to the Offsite Dose Calculation Manual.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 14 M. Groundwater Monitoring and Program (NEI 07-07)

Monitoring Wells The Groundwater Protection Initiative, GPI, identifies actions to improve utilities management and response to instances where the inadvertent release of radioactive substances may result in low but detectable levels of plant related materials in subsurface soil and water. This initiative provides guidelines on how to implement an effective Groundwater Protection Program. Sequoyah Nuclear Plant started investigating tritium releases to the groundwater in 2003 due to the identification of tritium in one of the on-site monitoring wells. This study involved pressure testing of the radwaste discharge line, installation and sampling of groundwater wells, visual inspection under the refueling water storage tanks (RWSTs) and inspection of drain lines. In addition to the one on-site Radiological Environmental Monitoring Program (REMP) groundwater monitoring well, SQN also has 29 non-REMP monitoring wells to support monitoring the onsite groundwater plume and for the presence or increase of radioactivity. SQN updated the number of wells in 2019 to better monitor the onsite groundwater. These wells are sampled periodically for tritium. The tritium concentrations obtained in 2024 from these non-REMP wells are listed below. Tritium fluctuation in Well 47i continues to be observed and is consistent with seasonal variation due to sources from previously documented legacy releases. No leaks to site groundwater are currently present. Ni-63 has also been observed in W10 since its installation in 2011. This has been investigated and determined to be from documented spills in the 1980s that are documented in the sites Site Conceptual Model. Concentrations of Ni-63 at W10 have remained above USEPA drinking water standards since March 2012. The activity of Ni-63 at W10 has continued to decrease since April 2015.

Well name Date and time Tritium, pCi/L Well name Date and time Tritium, pCi/L W9 4/3/2024 18:25

< 1.910E+02 W39 4/2/2024 14:20

< 1.940E+02 10/29/2024 17:45

< 2.380E+02 10/29/2024 15:30

< 2.440E+02 W10 1/11/2024 14:45 2.010E+03 W40 10/29/2024 14:15

< 2.380E+02 4/4/2024 12:45 1.220E+03 W41 10/29/2024 12:00

< 2.400E+02 7/24/2024 15:00 1.890E+03 W42 1/10/2024 14:55

< 1.850E+02 10/30/2024 17:15 1.160E+03 4/2/2024 17:35

< 1.940E+02 W11 1/11/2024 14:15

< 1.810E+02 7/24/2024 13:30

< 1.990E+02 4/4/2024 13:20

< 2.240E+02 10/29/2024 12:45

< 2.400E+02 7/24/2024 14:15

< 1.510E+02 W43 1/10/2024 13:35 3.430E+02 10/30/2024 16:15

< 2.120E+02 4/3/2024 11:30

< 1.950E+02 W12 1/11/2024 15:25 4.580E+02 7/23/2024 16:00

< 1.850E+02 4/4/2024 12:00

< 2.190E+02 10/29/2024 16:30

< 2.370E+02 7/24/2024 15:50 4.510E+02 W44 1/10/2024 14:20

< 1.880E+02 10/30/2024 15:25 2.760E+02 4/3/2024 12:05 3.190E+02 W13 1/10/2024 15:35

< 1.870E+02 7/23/2024 17:00 3.770E+02 4/2/2024 18:15

< 1.930E+02 10/30/2024 11:45

< 2.430E+02 W13 7/23/2024 14:45

< 1.840E+02 10/29/2024 14:45

< 2.330E+02

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 15 Well name Date and time Tritium, pCi/L Well name Date and time Tritium, pCi/L W15 1/11/2024 12:55

< 1.880E+02 W45i 1/11/2024 12:20

< 1.810E+02 4/3/2024 16:10

< 1.960E+02 4/3/2024 14:25

< 1.970E+02 7/23/2024 15:20

< 1.900E+02 7/24/2024 16:45

< 2.250E+02 10/30/2024 12:20

< 2.400E+02 10/30/2024 13:40

< 2.060E+02 W16 1/10/2024 10:50 3.750E+02 W45s 1/11/2024 11:45 1.960E+02 4/26/2024 14:00 7.990E+02 4/3/2024 15:00 1.980E+02 7/23/2024 20:00

< 2.440E+02 7/24/2024 17:20 4.270E+02 10/29/2023 18:45 4.040E+02 10/30/2024 14:00

< 2.160E+02 W18 1/10/2024 11:35 3.670E+02 W46i 1/10/2024 12:50 4.580E+02 4/2/2024 15:40 2.360E+02 4/2/2024 16:30 1.960E+02 7/23/2024 18:50 4.440E+02 7/23/2024 17:40 5.620E+02 10/30/2024 19:20

< 2.170E+02 10/30/2024 17:55 2.220E+02 W24 4/4/2024 14:25

< 2.250E+02 W46s 1/10/2024 12:15

< 1.840E+02 10/31/2024 17:05 2.360E+02 4/2/2024 17:00

< 1.960E+02 W25 4/4/2024 15:00

< 2.250E+02 7/23/2024 18:15 2.570E+02 10/31/2024 16:30

< 2.020E+02 10/30/2024 18:40

< 2.160E+02 W26 4/4/2024 15:40

< 2.190E+02 W47i 1/12/2024 11:15 1.500E+04 10/31/2024 15:50

< 2.120E+02 4/3/2024 17:25 1.530E+04 W27 10/29/2024 13:25 5.920E+02 7/24/2024 19:25 2.880E+04 W28 NSR*

NSR*

9/10/2024 15:10 2.010E+04 W36 1/11/2024 13:35

< 1.860E+02 10/31/2024 12:25 2.220E+04 4/2/2024 18:45

< 1.920E+02 W47s 1/12/2024 10:45 5.840E+03 7/22/2024 16:05

< 1.470E+02 4/3/2024 16:50 8.290E+03 W37 10/31/2024 14:30

< 2.110E+02 7/24/2024 18:45 1.270E+04 9/10/2024 14:25 1.308E+04 W38 4/3/2024 10:45

< 1.920E+02 10/31/2024 11:40 1.040E+04 10/29/2024 18:25

< 2.480E+02 W48 1/12/2024 9:30 1.270E+03 4/2/2024 14:55 8.070E+02 7/23/2024 19:25 1.920E+03 10/29/2024 17:05 1.370E+03

NSR - W28 sample not required unless W42 indicates > LLD values. All W42 values in 2024 were < LLD.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 16 Doses from l-131 Water lngestion Pathway The REMP requirements as specified in Table 3.12-1 from NUREG 1301, "Offsite Does Calculation Manual Guidance: Standard Radiological Effluent Controls for Pressurized Water Reactors," April 1991, requires an I-131 specific analysis for drinking water pathway samples if the annual dose from I-131 is greater than 1 mrem. To evaluate the need for implementation of this additional analysis, the drinking water pathway dose from I-131 to the maximum organ and age group is calculated. The evaluation confirms that the drinking water pathway dose from I-131 was less than the 1 mrem limit and that the performance of the I-131 specific analysis is not required for SQN REMP drinking water samples.

N. Errata/Corrections to Previous ARERRs

1. Previous ARERRs have incorrectly listed the Quarterly Limit for Airborne Submersion Dose (Total Body and Skin) as 10 mrad. There is no stated Quarterly Limit for Individual Submersion Dose from Appendix I of 10 CFR Part 50. This error was noted in Tables 3-A, 3-B, 3-C, and 3-D, Doses from Airborne Effluents Q1-Q4, in section VII J. Additionally, this error was found in all previous Power Operated Relief Valve Radiological Impact Evaluations under Section II E (Batch Releases).

2. Power Operated Relief Valve Radiological Impact Evaluations (Section II E, Batch Releases) in previous ARERRs have reported Airborne Organ Doses (typically Child/Thyroid and Child/Total Body) in mrad while the applicable Quarterly Limit was stated in mrem. For consistency with Appendix I of 10 CFR Part 50, these doses should be reported in mrem.

3. In July 2023, a release to the environment occurred from the Auxiliary Building Exhaust due to a failed access panel located upstream of the monitored release point (0-RM-90-101),

and documented in CR# 1872170. Following discovery and repair of the access panel, this release was fully evaluated, quantified, and processed as a release (20231164.023.002.G).

The 2023 ARERR fully accounted for this release in the following: Section III Table 1-A, Gaseous Effluents - Summation of all Releases 3rd Quarter;Section III Table 1-B, Gaseous Effluents - Ground Level Releases (Continuous) 3rd Quarter;Section VII J Table 3-C, Doses from Airborne Effluents - 3rd Quarter;Section VII J Table 5, Total Dose from Fuel Cycle 3rd Quarter.

SQN is currently committed to RG 1.21 Rev. 1, which was utilized during the initial evaluation. RG 1.21 Revisions 2 and 3 provide more detailed criteria for evaluating and classifying an Abnormal Release. With additional consideration and plans to commit to the latest revision of RG 1.21, the July 2023 release has been reclassified as an Abnormal Release (CR# 1942704). This release should have been noted specifically in the 2023 ARERR Section II Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total I-131 Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 Infant / Thyroid (mrem) 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 Population / Thyroid (mrem) 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 17 F - Abnormal Releases, but was only included in the calculated totals release values and dose impacts.

III.

Gaseous Effluents Table 1-A Gaseous Effluents - Summation of all Releases Zeroes indicate that no radioactivity was present at detectable levels.

Applicable Limits are expressed in terms of dose. See Tables 3A-D.

N/A - Errors in measurement are not reported for these values since none were identified during the reporting period.

N/A - Values estimated based on Section II D.1.

Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Error %

A. Fission and Activation Gases

1. Total Release Curies 1.14E+01 1.27E+01 1.62E+00 1.76E-01 2.58E+01 11%

2. Average Release Rate for Period uCi/sec 1.45E+00 1.61E+00 2.04E-01 2.21E-02 8.17E-01

3. Percent of Tech Spec Limit B. Iodines

1. Total Release Curies 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 N/A**

2. Average Release Rate for Period uCi/sec 0.00E+01 0.00E+01 0.00E+01 0.00E+01

3. Percent of Tech Spec Limit C. Particulates

1. Total Release Curies 3.04E-06 1.60E-06 0.00E+01 0.00E+01 4.63E-06 N/A**

2. Average Release Rate for Period uCi/sec 3.86E-07 2.03E-07 0.00E+01 0.00E+01 1.47E-07

3. Percent of Tech Spec Limit D. Tritium

1. Total Release Curies 2.24E+01 1.70E+01 2.96E+01 1.85E+01 8.75E+01 15%

2. Average Release Rate for Period uCi/sec 2.85E+00 2.16E+00 3.72E+00 2.33E+00 2.77E+00

3. Percent of Tech Spec Limit E. Carbon-14

1. Total Release Curies 5.42E+00 4.74E+00 3.11E+00 2.15E+00 1.54E+01 N/A***

2. Average Release Rate for Period uCi/sec 6.90E-01 6.03E-01 3.91E-01 2.71E-01 4.89E-01

3. Percent of Tech Spec Limit

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 18 Table 1-B Gaseous Effluents - Ground Level Releases (Batch)

Zeroes indicate that no radioactivity was present at detectable levels.

Table 1-B Gaseous Effluents - Ground Level Releases (Continuous)

Zeroes indicate that no radioactivity was present at detectable levels.

Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total

1. Fission and Activation Gases Ar-41 Ci 8.87E+00 1.18E+01 1.24E+00 1.58E-01 2.20E+01

-133 Ci 2.38E+00 9.01E-01 3.76E-01 1.82E-02 3.68E+00

-135 Ci 1.19E-01 0.00E+01 1.17E-04 0.00E+01 1.20E-01 Total For Period Ci 1.14E+01 1.27E+01 1.62E+00 1.76E-01 2.58E+01

2. Iodines Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

3. Particulates Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

4. Gross Alpha Gross Alpha Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

5. Tritium H-3 Ci 1.13E+01 5.54E+00 6.25E+00 1.34E-01 2.32E+01

6. Carbon-14 C-14 Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total

1. Fission and Activation Gases Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

2. Iodines Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

3. Particulates Co-60 Ci 3.04E-06 1.60E-06 0.00E+01 0.00E+01 4.63E-06 Total For Period Ci 3.04E-06 1.60E-06 0.00E+01 0.00E+01 4.63E-06

4. Gross Alpha Gross Alpha Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

5. Tritium H-3 Ci 1.11E+01 1.15E+01 2.33E+01 1.84E+01 6.43E+01

6. Carbon-14 C-14 Ci 5.42E+00 4.74E+00 3.11E+00 2.15E+00 1.54E+01

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 19 IV.

Liquid Effluents Table 2-A Liquid Effluents - Summation of all Releases Zeroes indicate that no radioactivity was present at detectable levels.

Applicable Limits are expressed in terms of dose. See Tables 3A-D Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total Error %

A. Fission and Activation Products

1. Total Release Curies 9.14E-03 1.91E-02 3.79E-02 4.19E-03 7.03E-02 18%

2. Average Diluted Concentration uCi/mL 3.56E-09 7.49E-09 1.54E-08 2.61E-09 7.66E-09

4. Percent of Tech Spec Limit B. Tritium

1. Total Release Curies 1.00E+03 3.01E+02 1.53E+03 2.65E+02 3.09E+03 18%

2. Average Diluted Concentration uCi/mL 3.89E-04 1.18E-04 6.21E-04 1.65E-04 3.37E-04

4. Percent of Tech Spec Limit C. Dissolved and Entrained Noble Gases

1. Total Release Curies 1.44E-03 3.52E-05 9.85E-04 0.00E+01 2.46E-03 39%

2. Average Diluted Concentration uCi/mL 5.61E-10 1.38E-11 4.01E-10 0.00E+01 2.68E-10

4. Percent of Tech Spec Limit D. Gross Alpha Radioactivity

1. Total Release Curies 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01 N/A E. Volume of Liquid Waste to Discharge Canal (prior to dilution)

Liters 6.60E+07 6.48E+07 6.16E+07 4.83E+07 2.41E+08 4%

F. Volume of Dilution Water for Period Liters 2.50E+09 2.48E+09 2.40E+09 1.56E+09 8.94E+09 N/A

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 20 Table 2-B Liquid Effluents - Batch Mode Zeroes indicate that no radioactivity was present at detectable levels.

Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total

1. Fission and Activation Products Cr-51 Ci 6.61E-04 4.96E-03 2.72E-03 1.01E-04 8.44E-03 Mn-54 Ci 2.92E-04 1.88E-04 4.21E-05 4.05E-05 5.62E-04 Fe-55 Ci 2.01E-04 6.15E-04 3.39E-03 3.55E-04 4.56E-03 Co-58 Ci 5.89E-04 2.97E-03 4.67E-03 8.67E-04 9.09E-03 Fe-59 Ci 0.00E+01 7.81E-06 9.05E-06 1.98E-05 3.67E-05 Co-60 Ci 4.17E-03 4.32E-03 3.06E-03 9.09E-04 1.25E-02 Ni-63 Ci 2.19E-03 7.51E-04 2.39E-02 7.71E-04 2.76E-02 Zn-65 Ci 2.18E-04 2.06E-05 2.28E-05 4.97E-06 2.67E-04 Zr-95 Ci 1.92E-05 2.83E-04 8.50E-06 4.02E-05 3.51E-04 Nb-95 Ci 7.84E-05 5.56E-04 4.40E-05 1.52E-04 8.30E-04 Nb-97 Ci 0.00E+01 8.36E-06 7.01E-06 0.00E+01 1.54E-05 Ag-110m Ci 1.38E-05 4.27E-05 0.00E+01 0.00E+01 5.65E-05 Sb-122 Ci 0.00E+01 3.51E-05 0.00E+01 0.00E+01 3.51E-05 Sb-124 Ci 6.58E-06 1.43E-03 0.00E+01 1.37E-04 1.57E-03 Sb-125 Ci 2.34E-04 2.78E-03 5.74E-05 7.94E-04 3.86E-03 Sb-126 Ci 0.00E+01 6.39E-05 0.00E+01 0.00E+01 6.39E-05 Te-129 Ci 0.00E+01 3.64E-05 0.00E+01 0.00E+01 3.64E-05 Cs-137 Ci 4.74E-04 0.00E+01 0.00E+01 0.00E+01 4.74E-04 Total For Period Ci 9.14E-03 1.91E-02 3.79E-02 4.19E-03 7.03E-02

2. Dissolved and Entrained Gases

-133 Ci 1.41E-03 3.52E-05 9.74E-04 0.00E+01 2.42E-03

-135 Ci 3.29E-05 0.00E+01 1.09E-05 0.00E+01 4.38E-05 Total For Period Ci 1.44E-03 3.52E-05 9.85E-04 0.00E+01 2.46E-03

3. Tritium Total for the Period Ci 1.00E+03 3.01E+02 1.53E+03 2.65E+02 3.09E+03

4. Gross Alpha Activity Total for the Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 21 Table 2-B Liquid Effluents - Continuous Mode Zeroes indicate that no radioactivity was present at detectable levels.

Units 1st Quarter 2nd Quarter 3rd Quarter 4th Quarter Total

1. Fission and Activation Products Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

2. Dissolved and Entrained Gases Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

3. Tritium Total For Period Ci 1.48E-01 1.12E-01 1.07E-01 1.12E-01 4.79E-01

4. Gross Alpha Activity Total For Period Ci 0.00E+01 0.00E+01 0.00E+01 0.00E+01 0.00E+01

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 22 V.

Solid Waste Storage and Shipment A. Types of Solid Waste - Summary Solid Waste Shipped Offsite for Burial or Disposal (not Irradiated Fuel)

1. Type of Waste

a. Spent Resins, Filter Sludges, Evaporator Bottoms, etc.

b. Dry Active Waste, Compressible Waste Contaminated Equipment, etc.

c. Irradiated Components, Control Rods, etc.

d. Other: Glycol Sent for Processing Unit m3 Ci m3 Ci m3 Ci m3 Ci 12 Month Period 13.5 1.38E+02 581 1.99E+00 0.00 0.00E+00 23.0 7.98E-03 Est. Tot.

Error %

+5.00E-01

+2.29E+01

+1.00E+01

+2.29E+01

+1.00E+01

+2.29E+01

+1.00E+01

+2.29E+01 The reported volume for category a waste is based on the volume of the disposal container. Waste volumes for categories b, c, and d are based on the net waste volume rather than the shipping container volume. During transit, the waste for category b may settle resulting in an overall reduced volume. The reduction in disposal volume is estimated to be 10 percent due to settling. Volume estimates for category b wastes were based on a visual inspection of the containers contents and its percent full.

The estimated total error (percent) for the total Curies shipped is based on calculating the square root of the sum of the squares method. Three parameters were considered as important for estimating the error. The parameters were variances with sample preparation and counting geometry, survey instrument accuracy for dose to Curie evaluations, and in-field sampling techniques. The assigned values for these parameters were 20, 10, and 5 percent, respectively.

Total error (%) = (0.202 + 0.102 + 0.052)1/2 x 100 = 22.9%

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 23 B. Estimate of Major Nuclide Composition (by waste type)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 24

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report 25 C. Solid Waste Disposition

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 26 VI.

Independent Spent Fuel Storage Installation SQN implemented use of an independent spent fuel storage installation (ISFSI) on July 13, 2004. 10 CFR 72.214 Certificate of Compliance (CoC) Nos. 1014 and 1032 correspond to the two certificates of the spent fuel storage systems in use at the ISFSI. The ISFSI is located on site, within the protected area and is designed to hold 90 spent fuel storage canisters (SFSCs). CoC Nos. 1014 and 1032 Appendix A Chapter 5 requires an annual report in accordance with 10 CFR 72.44(d)(3). CoC Nos. 1014 and 1032 Chapter 5 also provides that the ISFSI operations may be considered part of plant operations for the purposes of the radiological environmental monitoring program.

CoC No. 1014 Section 5.4a states The HI-STORM 100 Cask System does not create any radioactive material or have any radioactive waste treatment systems. Therefore, specific operating procedures for the control of radioactive effluents are not required.

Specification 3.1.1, Multi-Purpose Canister (MPC), provides assurance that there are not radioactive effluents from SFSC.

CoC No. 1032 Section 5.1a states, The HI-STORM FW MPC Storage System does not create any radioactive materials or have any radioactive waste treatment systems. Therefore, specific operating procedures for the control of radioactive effluents are not required.

Specification 3.1.1, Multi-Purpose Canister (MPC), provides assurance that there are not radioactive effluents from the SFSC.

The Environmental Protection Agency limits for the total dose to the public in the vicinity of a nuclear power plant, established in the Environmental Dose Standard of 40 CFR 190, are as follows:

Total Body Thyroid Any other organ Although CoC Nos. 1014 and 1032 provide that the HI-STORM 100 Cask System and HI-STORM FW MPC Storage System do not create any radioactive material or have any radioactive waste treatment systems, for this report, total site releases include the SQN ISFSI as part of the SQN site and part of plant operations. These releases are within 40 CFR 190 limits and 10 CFR 72.104 limits.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 27 VII.

Radiological Impact to Man A. Introduction Potential doses to maximum individuals and the population around Sequoyah Nuclear Plant (SQN) are calculated for each quarter as required in Section 5.2 of the Offsite Dose Calculation Manual (ODCM). Measured plant releases for the reporting period are used to estimate these doses. Dispersion of radioactive effluents in the environment is estimated using meteorological data and river flow data. In this report, the doses resulting from releases are described and compared to limits established for SQN.

B. Dose Limits The ODCM specifies limits for the release of radioactive effluents, as well as limits for doses to the general public from the release of radioactive effluents. These limits are set well below the Technical Specification limits which govern the concentrations of radioactivity and doses permissible in unrestricted areas. This ensures that radioactive effluent releases are As Low As Reasonably Achievable.

The limits for doses in unrestricted areas from airborne noble gases released are:

Less than or equal to 5 mrad per quarter and 10 mrad per year (per reactor unit) for gamma radiation Less than or equal to 10 mrad per quarter and 20 mrad per year (per reactor unit) for beta radiation.

The limit for the dose to a member of the general public in an unrestricted area from Iodines and particulates released in airborne effluents is:

Less than or equal to 7.5 mrem per quarter and 15 mrem per year (per reactor unit) to any organ.

The limits for doses to a member of the general public from radioactive material in liquid effluents released to unrestricted areas are:

Less than or equal to 1.5 mrem per quarter and 3 mrem per year (per reactor unit) to the total body Less than or equal to 5 mrem per quarter and 10 mrem per year (per reactor unit) to any organ.

The Environmental Protection Agency limits for total dose to the public in the vicinity of a nuclear power plant, established in the Environmental Dose Standard of 40 CFR 190 are:

Less than or equal to 25 mrem per year to the total body, Less than or equal to 75 mrem per year to the thyroid, Less than or equal to 25 mrem per year to any other organ.

C. Dose Calculations Estimated doses to the public are determined using computer models: Gaseous Effluent Licensing Code (GELC), and the Quarterly Water Dose Assessment Code (QWATA). These models are based on guidance provided by the NRC (in Regulatory Guides 1.109, 1.111 and 1.113) for determining the potential dose to individuals and populations living in the vicinity

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 28 of the plant. The area around the plant is analyzed to determine the pathways through which the public may receive a dose. The doses calculated are a representation of the dose to a "maximum exposed individual." Some of the factors used in these calculations (such as ingestion rates) are maximum values. Many of these factors are obtained from NUREG/CR-1004. The values chosen will tend to overestimate the dose to this "maximum" person. The expected dose to actual individuals is lower. The calculated doses are presented in Tables 3 and 4.

D. Doses from Airborne Effluents For airborne effluents, the public can be exposed to radiation from several sources: direct radiation from the radioactivity in the air, direct radiation from radioactivity deposited on the ground, inhalation of airborne radioactivity, ingestion of vegetation which contains radioactivity deposited from the atmosphere, and ingestion of milk and beef which contains radioactivity deposited from the atmosphere onto vegetation and subsequently eaten by milk and beef animals.

Airborne Discharge Points All releases from SQN are considered ground-level releases. The ground-level Joint Frequency Distribution (JFD) is derived from wind speeds and directions measured 10 meters above ground and from the vertical temperature difference between 10 and 46 meters, as presented for each quarter in Section VIII Meteorological Data.

Meteorological Data Meteorological variables at SQN are measured continuously. Measurements collected include wind speed, wind direction, and temperature at heights of 10, 46, and 91 meters above the ground. Quarterly JFDs are calculated for each release point using the appropriate levels of meteorological data. A JFD provides the percentage of the time in a quarter that the wind is blowing out of a particular upwind compass sector in a particular range of wind speeds for a given stability class A through G. The wind speeds are divided into nine wind speed ranges. Calms are distributed by direction in proportion to the distribution of non-calm wind directions less than 0.7 m/s (1.5 mph). Stability classes are determined from the vertical temperature difference between two measurement levels.

External Exposure Dose Dose estimates for maximum external air dose (gamma-air and beta-air doses) are made for points at and beyond the unrestricted area boundary as described in the SQN ODCM. The highest of these doses is then selected.

Submersion Dose External doses to the skin and total body, due to submersion in a cloud of noble gases, are estimated for the nearest residence in each sector. The residence with the highest dose is then selected from all sectors.

Organ Dose Doses to organs due to releases of airborne effluents are estimated for the inhalation, ground contamination, and ingestion pathways. The ingestion pathway is further divided into four possible contributing pathways: ingestion of cow milk, ingestion of beef, and ingestion of vegetables. Doses from applicable pathways are calculated for each real receptor location identified in the most recent land use survey. To determine the maximum organ dose, the

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 29 doses from the pathways are summed for each receptor. For the ingestion dose, however, only those pathways that exist for each receptor are considered in the sum, i.e., milk ingestion doses are included only for locations where milk is consumed without commercial preparation and vegetable ingestion is included only for those locations where a garden is identified. To conservatively account for beef ingestion, a beef ingestion dose equal to that for the highest unrestricted area boundary location is added to each identified receptor. For ground contamination, the dose added to the organ dose being calculated is the total body dose calculated for that location, i.e., it is assumed that the dose to an individual organ is equal to the total body dose.

Doses from airborne effluents are presented in Table 3.

E. Doses from Liquid Effluents For liquid effluents, the public can be exposed to radiation from three sources: the ingestion of water from the Tennessee River, the ingestion of fish caught in the Tennessee River, and direct exposure from radioactive material deposited on the river shoreline sediment (recreation).

The concentrations of radioactivity in the Tennessee River are estimated by a computer model which uses measured hydraulic data downstream of SQN. Parameters used to determine the doses are based on guidance given by the NRC (in Regulatory Guide 1.109) for maximum ingestion rates, exposure times, etc. Wherever possible, parameters used in the dose calculation are site specific use factors determined by TVA. The models that are used to estimate doses, as well as the parameters input to the models, are described in detail in the SQN ODCM.

Liquid Release Points and River Data Radioactivity concentrations in the Tennessee River are calculated assuming that releases in liquid effluents are continuous. Routine liquid releases from SQN, located at Tennessee River Mile 484, are made through diffusers which extend into the Tennessee River. It is assumed that releases to the river through these diffusers will initially be entrained in one-fifth of the water which flows past the plant. The QWATA code assumes that this mixing condition holds true until the water is completely mixed at the first downstream dam, at Tennessee River Mile 471.

Doses are calculated for locations within a 50-mile radius downstream of the plant site.

The maximum potential recreation dose is calculated for a location immediately downstream from the plant outfall. The maximum individual dose from ingestion of fish is assumed to be that calculated for the consumption of fish caught anywhere between the plant and the first downstream dam (Chickamauga Dam). The maximum individual dose from drinking water is assumed to be that calculated at the nearest downstream public water supply (East Side Utilities). This could be interpreted as indicating that the maximum individual, as assumed for liquid releases from Sequoyah, is an individual who obtains all of his drinking water at East Side Utilities, consumes fish caught from the Tennessee River between SQN and Chickamauga Dam, and spends 500 hours0.00579 days 0.139 hours 8.267196e-4 weeks 1.9025e-4 months per year on the shoreline just below the outfall from Sequoyah. Dose estimates for the maximum individual due to liquid effluents for each quarter in the period are presented in Table 4, along with the average river flows past the plant site for the periods.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 30 Population doses are calculated assuming that each individual consumes milk, vegetables, and meat produced within the sector annulus in which he resides. Doses from external pathways and inhalation are based on the 50-mile human population distribution.

F. Population Doses Population doses for highest exposed organ due to airborne effluents are calculated for an estimated 1,060,000 persons living within a 50-mile radius of the plant site. Doses from external pathways and inhalation are based on the 50-mile human population distribution.

Ingestion population doses for total body and the maximum exposed organ due to liquid effluents are calculated for the entire downstream Tennessee River population. Water ingestion population doses are calculated using actual population figures for downstream public water supplies. Fish ingestion population doses are calculated assuming that all sport fish caught in the Tennessee River are consumed by the Tennessee River population.

Recreation population doses are calculated using actual recreational data on the number of shoreline visits at downstream locations.

Population dose estimates for airborne and liquid effluents are presented in Tables 3 and

4.

G. Offsite Direct Radiation Dose External gamma radiation levels were measured by dosimeters deployed around SQN as part of the offsite REMP. The quarterly gamma radiation levels determined from these dosimeters during this reporting period averaged approximately 14.4 mrem/quarter at onsite (at or near the site boundary) stations and approximately 13.4 mrem/quarter at offsite stations, or approximately 1.0 mrem/quarter higher onsite than at offsite stations. This difference is consistent with levels measured for preoperational and construction phases of the TVA nuclear plant site where the average radiation levels onsite were generally 1-3 mrem/quarter higher than the levels offsite. This may be attributable to natural variations in environmental radiation levels, earth moving activities onsite, the mass of concrete employed in the construction of the plants, or other undetermined influences. Fluctuations in natural background dose rates and in dosimeters readings tend to mask any small increments which may be due to plant operations. Thus, there was no identifiable increase in dose rate levels attributable to direct radiation from plant equipment and/or gaseous effluents.

H. Dose to a Member of the Public Inside the Site Boundary As stated in the SQN ODCM, an evaluation of the dose to a member of the public inside the unrestricted area boundary is performed for a hypothetical TVA employee who works just outside the restricted area boundary for an entire work year (2000 hours0.0231 days 0.556 hours 0.00331 weeks 7.61e-4 months ). Results from onsite dosimeter measurements for 2024 indicate that the highest onsite dosimeter reading was 25 mrem (Livewell Building) after subtraction of the annual background value of 61 mrem/year (from perimeter dosimeters around Sequoyah). Using this value and multiplying by the ratio of the occupancy times (2000/8784 for a leap year), the external dose was 5.69 mrem. The doses due to radioactive effluents released to the atmosphere calculated in this report would not add a significant amount to this measured dose. This dose is well below the 10 CFR 20 annual limit of 100 mrem.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 31 I. Total Dose To determine compliance with 40 CFR 190, annual total dose contributions to the maximum individual from SQN radioactive effluents and other nearby uranium fuel cycle sources are considered.

The annual dose to any organ other than thyroid for the maximum individual is conservatively estimated by summing the following doses: the total body air submersion dose for each quarter, the critical organ dose (for any organ other than the thyroid) from airborne effluents for each quarter from ground contamination, inhalation and ingestion, the total body dose from liquid effluents for each quarter, the maximum organ dose (for any organ other than the thyroid) from liquid effluents for each quarter, and any identifiable increase in direct radiation dose levels as measured by the environmental monitoring program. This dose is compared to the 40 CFR 190 limit for total body or any organ dose (other than thyroid) to determine compliance.

The annual thyroid dose to the maximum individual is conservatively estimated by summing the following doses: the total body air submersion dose for each quarter, the thyroid dose from airborne effluents for each quarter, the total body dose from liquid effluents for each quarter, the thyroid dose from liquid effluents for each quarter, and any identifiable increase in direct radiation dose levels as measured by the environmental monitoring program. This dose is compared to the 40 CFR 190 limit for thyroid dose to determine compliance.

Cumulative annual total doses are presented in Table 5.

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 32 J. Tables Table 3-A Doses from Airborne Effluents - 1st Quarter Individual Doses Pathway Dose Quarterly Limit Percent of Limit Location External Gamma Air 1.23E-02 mrad 5 mrad

<1%

N/950/meters Beta Air 4.75E-03 mrad 10 mrad

<1%

N/950/meters Submersion Total Body 7.59E-03 mrad N/A N/A SSW/2059/meters Skin 1.13E-02 mrad N/A N/A SSW/2059/meters Organ Doses (Iodine, Tritium, Particulates with >8-Day half-life)

Child / Bone (Max) 4.84E-01 mrem 7.5 mrem 6.5%

WSW/1152/meters Child / Thyroid 1.09E-01 mrem 7.5 mrem 1.5%

WSW/1152/meters Child / Total Body 1.09E-01 mrem 7.5 mrem 1.5%

WSW/1152/meters Population Doses Total Body Dose 6.28E-01 man-rem Maximum Organ Dose (Organ) 2.65E+00 man-rem (Bone)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 33 Table 3-B Doses from Airborne Effluents - 2nd Quarter Individual Doses Pathway Dose Quarterly Limit Percent of Limit Location External Gamma Air 1.79E-02 mrad 5 mrad

<1%

N/950/meters Beta Air 6.45E-03 mrad 10 mrad

<1%

N/950/meters Submersion Total Body 9.05E-03 mrad N/A N/A N/1389/meters Skin 1.33E-02 mrad N/A N/A N/1389/meters Organ Doses (Iodine, Tritium, Particulates with >8-Day half-life)

Child / Bone (Max) 3.35E-01 mrem 7.5 mrem 4.5%

WSW/1152/meters Child / Thyroid 7.48E-02 mrem 7.5 mrem

<1%

WSW/1152/meters Child / Total Body 7.48E-02 mrem 7.5 mrem

<1%

WSW/1152/meters Population Doses Total Body Dose 4.31E-01 man-rem Maximum Organ Dose (Organ) 1.85E+00 man-rem (Bone)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 34 Table 3-C Doses from Airborne Effluents - 3rd Quarter Individual Doses Pathway Dose Quarterly Limit Percent of Limit Location External Gamma Air 1.66E-03 mrad 5 mrad

<1%

SSW/1840/meters Beta Air 6.47E-04 mrad 10 mrad

<1%

SSW/1840/meters Submersion Total Body 1.30E-03 mrad N/A N/A SSW/2059/meters Skin 1.93E-03 mrad N/A N/A SSW/2059/meters Organ Doses (Iodine, Tritium, Particulates with >8-Day half-life)

Child / Bone (Max) 2.58E-01 mrem 7.5 mrem 3.4%

WSW/1152/meters Child / Thyroid 6.18E-02 mrem 7.5 mrem

<1%

WSW/1152/meters Child / Total Body 6.18E-02 mrem 7.5 mrem

<1%

WSW/1152/meters Population Doses Total Body Dose 4.69E-01 man-rem Maximum Organ Dose (Organ) 1.71E+00 man-rem (Bone)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 35 Table 3-D Doses from Airborne Effluents - 4th Quarter Individual Doses Pathway Dose Quarterly Limit Percent of Limit Location External Gamma Air 2.52E-04 mrad 5 mrad

<1%

SSW/1840/meters Beta Air 9.26E-05 mrad 10 mrad

<1%

SSW/1840/meters Submersion Total Body 1.99E-04 mrad N/A N/A SSW/2059/meters Skin 2.93E-04 mrad N/A N/A SSW/2059/meters Organ Doses (Iodine, Tritium, Particulates with >8-Day half-life)

Child / Bone (Max) 2.01E-01 mrem 7.5 mrem 2.7%

SSW/4363/meters Child / Thyroid 4.71E-02 mrem 7.5 mrem

<1%

SSW/4363/meters Child / Total Body 4.71E-02 mrem 7.5 mrem

<1%

SSW/4363/meters Population Doses Total Body Dose 3.66E-01 man-rem Maximum Organ Dose (Organ) 1.37E+00 man-rem (Bone)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 36 Table 4-A Doses from Liquid Effluents - 1st Quarter Individual Doses Age Group Organ Dose Quarterly Limit Percent of Limit Child (Max)

Bone 4.35E-03 mrem 5 mrem

< 1 %

Child Thyroid 4.23E-03 mrem 5 mrem

< 1 %

Child Total Body 4.25E-03 mrem 1.5 mrem

< 1 %

Average Riverflow past SQN (cubic feet per second): 46,601 Population Doses Total Body Dose 2.85E-01 man-rem Maximum Organ Dose (Organ) 2.86E-01 man-rem (Bone/Liver)

Table 4-B Doses from Liquid Effluents - 2nd Quarter Individual Doses Age Group Organ Dose Quarterly Limit Percent of Limit Child (Max)

GIT 3.07E-03 mrem 5 mrem

< 1 %

Child Thyroid 2.91E-03 mrem 5 mrem

< 1 %

Child Total Body 2.92E-03 mrem 1.5 mrem

< 1 %

Average Riverflow past SQN (cubic feet per second): 22,060 Population Doses Total Body Dose 2.21E-01 man-rem Maximum Organ Dose (Organ) 2.23E-01 man-rem (GIT)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 37 Table 4-C Doses from Liquid Effluents - 3rd Quarter Individual Doses Age Group Organ Dose Quarterly Limit Percent of Limit Child (Max)

Bone 1.40E-02 mrem 5 mrem

< 1 %

Child Thyroid 1.33E-02 mrem 5 mrem

< 1 %

Child Total Body 1.33E-02 mrem 1.5 mrem

< 1 %

Average Riverflow past SQN (cubic feet per second): 23,164 Population Doses Total Body Dose 8.69E-01 man-rem Maximum Organ Dose (Organ) 9.00E-01 man-rem (Bone)

Table 4-D Doses from Liquid Effluents - 4th Quarter Individual Doses Age Group Organ Dose Quarterly Limit Percent of Limit Child (Max)

GIT 1.57E-03 mrem 5 mrem

< 1 %

Child Thyroid 1.54E-03 mrem 5 mrem

< 1 %

Child Total Body 1.54E-03 mrem 1.5 mrem

< 1 %

Average Riverflow past SQN (cubic feet per second): 34,731 Population Doses Total Body Dose 1.04E-01 man-rem Maximum Organ Dose (Organ) 1.05E-01 man-rem (GIT)

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Radiological Impact 38 Table 5 Total Dose from Fuel Cycle Dose First Quarter Second Quarter Third Quarter Fourth Quarter Total Body or any Organ (except thyroid)

Total body air (submersion) 7.59E-03 9.05E-03 1.30E-03 1.99E-04 Critical organ dose (airborne) 4.84E-01 3.35E-01 2.58E-01 2.01E-01 Total body dose (liquid) 4.25E-03 2.92E-03 1.33E-02 1.54E-03 Maximum organ dose (liquid) 4.35E-03 3.07E-03 1.40E-02 1.57E-03 Direct Radiation Dose 0.00E+01 0.00E+01 0.00E+01 0.00E+01 Total 5.00E-01 3.50E-01 2.87E-01 2.04E-01 Cumulative Total Dose (mrem) 1.34 Annual Dose Limit (mrem) 25 Percent of Limit 5.36 Thyroid Total body air (submersion) 7.59E-03 9.05E-03 1.30E-03 1.99E-04 Thyroid dose (airborne) 1.09E-01 7.48E-02 6.18E-02 4.71E-02 Total body dose (liquid) 4.25E-03 2.92E-03 1.33E-02 1.54E-03 Thyroid dose (liquid) 4.23E-03 2.91E-03 1.33E-02 1.54E-03 Total 1.25E-01 8.97E-02 8.97E-02 5.04E-02 Cumulative Total Dose (mrem) 0.355 Annual Dose Limit (mrem) 75 Percent of Limit <1

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 39 VIII. Meteorological Data

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 40 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS A (DELTA T<=-1.9 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.000 0.092 0.184 0.046 0.000 0.000 0.322 NNE 0.000 0.000 0.092 0.092 0.230 0.414 0.046 0.000 0.000 0.874 NE 0.000 0.000 0.092 0.230 0.046 0.092 0.000 0.000 0.000 0.460 ENE 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.046 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ESE 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.046 SE 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 SSE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 S 0.000 0.000 0.000 0.000 0.138 0.092 0.000 0.000 0.000 0.230 SSW 0.000 0.000 0.000 0.000 0.276 0.506 0.000 0.000 0.000 0.782 SW 0.000 0.000 0.000 0.000 0.092 0.092 0.000 0.000 0.000 0.184 WSW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 W 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.000 0.000 0.000 0.000 0.322 0.092 0.000 0.000 0.414 NNW 0.000 0.000 0.000 0.000 0.046 0.230 0.000 0.000 0.000 0.276 SUBTOTAL 0.000 0.000 0.230 0.414 0.920 1.932 0.184 0.000 0.000 3.680 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS A 80 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS A 80 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 7.91 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 41 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS B (-1.9< DELTA T<=-1.7 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.000 0.276 0.230 0.000 0.000 0.000 0.506 NNE 0.000 0.000 0.046 0.414 0.322 0.322 0.046 0.000 0.000 1.150 NE 0.000 0.000 0.092 0.184 0.092 0.138 0.000 0.000 0.000 0.506 ENE 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.046 E 0.000 0.000 0.000 0.138 0.000 0.000 0.000 0.000 0.000 0.138 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SSE 0.000 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.092 S 0.000 0.000 0.000 0.000 0.092 0.230 0.000 0.000 0.000 0.322 SSW 0.000 0.000 0.000 0.046 0.460 0.506 0.000 0.000 0.000 1.012 SW 0.000 0.000 0.000 0.046 0.230 0.000 0.000 0.000 0.000 0.276 WSW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 W 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.046 WNW 0.000 0.000 0.000 0.000 0.000 0.092 0.046 0.000 0.000 0.138 NW 0.000 0.000 0.000 0.000 0.046 0.092 0.000 0.000 0.000 0.138 NNW 0.000 0.000 0.000 0.046 0.046 0.184 0.000 0.000 0.000 0.276 SUBTOTAL 0.000 0.000 0.230 0.966 1.610 1.794 0.092 0.000 0.000 4.692 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS B 102 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS B 102 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 7.02 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 42 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS C (-1.7< DELTA T<=-1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.138 0.138 0.552 0.000 0.000 0.000 0.828 NNE 0.000 0.000 0.000 0.138 0.322 0.460 0.000 0.000 0.000 0.920 NE 0.000 0.000 0.092 0.000 0.092 0.046 0.000 0.000 0.000 0.230 ENE 0.000 0.000 0.046 0.092 0.000 0.000 0.000 0.000 0.000 0.138 E 0.000 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.092 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SSE 0.000 0.000 0.000 0.046 0.046 0.046 0.000 0.000 0.000 0.138 S 0.000 0.000 0.046 0.000 0.138 0.046 0.000 0.000 0.000 0.230 SSW 0.000 0.000 0.000 0.368 0.506 0.046 0.000 0.000 0.000 0.920 SW 0.000 0.000 0.092 0.138 0.276 0.000 0.046 0.000 0.000 0.552 WSW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 W 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 WNW 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 NW 0.000 0.000 0.000 0.000 0.092 0.092 0.000 0.000 0.000 0.184 NNW 0.000 0.000 0.000 0.046 0.046 0.092 0.000 0.000 0.000 0.184 SUBTOTAL 0.000 0.000 0.322 1.012 1.656 1.472 0.046 0.000 0.000 4.508 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS C 98 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS C 98 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 6.81 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 43 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS D (-1.5< DELTA T<=-0.5 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.046 0.828 1.656 1.334 1.334 0.000 0.000 0.000 5.198 NNE 0.000 0.046 1.472 1.978 1.840 2.346 0.000 0.000 0.000 7.682 NE 0.000 0.000 0.736 0.414 0.322 0.276 0.000 0.000 0.000 1.748 ENE 0.000 0.000 0.322 0.046 0.000 0.000 0.000 0.000 0.000 0.368 E 0.000 0.000 0.230 0.000 0.000 0.000 0.000 0.000 0.000 0.230 ESE 0.000 0.000 0.138 0.000 0.000 0.000 0.000 0.000 0.000 0.138 SE 0.000 0.000 0.322 0.138 0.000 0.000 0.000 0.000 0.000 0.460 SSE 0.000 0.046 0.322 0.184 0.092 0.138 0.046 0.000 0.000 0.828 S 0.000 0.092 0.966 0.690 0.460 0.736 0.092 0.000 0.000 3.036 SSW 0.000 0.000 1.334 2.760 1.150 0.414 0.000 0.000 0.000 5.658 SW 0.000 0.000 0.874 1.426 1.058 0.322 0.000 0.000 0.000 3.680 WSW 0.000 0.000 0.184 0.552 0.552 0.690 0.000 0.000 0.000 1.978 W 0.000 0.046 0.184 0.092 0.138 0.184 0.000 0.000 0.000 0.644 WNW 0.000 0.000 0.138 0.000 0.276 0.092 0.046 0.000 0.000 0.552 NW 0.000 0.092 0.138 0.276 0.690 0.552 0.000 0.000 0.000 1.748 NNW 0.000 0.000 0.322 0.736 1.564 1.058 0.000 0.000 0.000 3.680 SUBTOTAL 0.000 0.368 8.510 10.948 9.476 8.142 0.184 0.000 0.000 37.626 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS D 818 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS D 818 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 5.53 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 44 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS E (-0.5< DELTA T<= 1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.184 1.840 0.966 0.138 0.046 0.000 0.000 0.000 3.174 NNE 0.000 0.368 3.312 1.380 0.782 0.184 0.000 0.000 0.000 6.026 NE 0.000 0.092 0.782 0.230 0.046 0.000 0.000 0.000 0.000 1.150 ENE 0.000 0.138 0.138 0.046 0.000 0.000 0.000 0.000 0.000 0.322 E 0.000 0.138 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.184 ESE 0.000 0.092 0.138 0.000 0.000 0.000 0.000 0.000 0.000 0.230 SE 0.000 0.046 0.276 0.000 0.000 0.000 0.000 0.000 0.000 0.322 SSE 0.000 0.138 0.460 0.046 0.000 0.000 0.000 0.000 0.000 0.644 S 0.000 0.000 1.380 0.368 0.920 0.552 0.000 0.000 0.000 3.220 SSW 0.000 0.230 2.392 1.058 0.598 1.104 0.000 0.000 0.000 5.382 SW 0.000 0.184 1.518 0.828 0.092 0.138 0.000 0.000 0.000 2.760 WSW 0.000 0.092 0.552 0.276 0.046 0.230 0.000 0.000 0.000 1.196 W 0.000 0.000 0.184 0.046 0.000 0.046 0.000 0.000 0.000 0.276 WNW 0.000 0.000 0.230 0.046 0.092 0.000 0.000 0.000 0.000 0.368 NW 0.000 0.000 0.506 0.230 0.092 0.092 0.000 0.000 0.000 0.920 NNW 0.000 0.230 0.644 0.690 0.092 0.000 0.000 0.000 0.000 1.656 SUBTOTAL 0.000 1.932 14.397 6.210 2.898 2.392 0.000 0.000 0.000 27.829 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS E 605 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS E 605 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 3.76 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 45 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS F ( 1.5< DELTA T<= 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.046 0.598 0.046 0.000 0.000 0.000 0.000 0.000 0.690 NNE 0.000 0.414 2.852 0.828 0.000 0.000 0.000 0.000 0.000 4.094 NE 0.000 0.460 1.472 0.046 0.000 0.000 0.000 0.000 0.000 1.978 ENE 0.000 0.184 0.230 0.000 0.000 0.000 0.000 0.000 0.000 0.414 E 0.000 0.046 0.230 0.000 0.000 0.000 0.000 0.000 0.000 0.276 ESE 0.000 0.046 0.138 0.046 0.000 0.000 0.000 0.000 0.000 0.230 SE 0.000 0.046 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.138 SSE 0.000 0.184 0.184 0.000 0.000 0.000 0.000 0.000 0.000 0.368 S 0.000 0.184 0.644 0.092 0.046 0.000 0.000 0.000 0.000 0.966 SSW 0.000 0.230 1.288 0.598 0.000 0.000 0.000 0.000 0.000 2.116 SW 0.000 0.138 1.196 0.046 0.000 0.000 0.000 0.000 0.000 1.380 WSW 0.000 0.000 0.460 0.000 0.000 0.000 0.000 0.000 0.000 0.460 W 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.092 NNW 0.000 0.000 0.184 0.000 0.000 0.000 0.000 0.000 0.000 0.184 SUBTOTAL 0.000 2.024 9.614 1.702 0.046 0.000 0.000 0.000 0.000 13.385 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS F 291 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS F 291 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 2.33 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 46 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS G (DELTA T > 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT JAN 1, 2024 - MAR 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.046 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.138 NNE 0.000 0.092 0.966 0.092 0.000 0.000 0.000 0.000 0.000 1.150 NE 0.000 0.506 1.656 0.184 0.000 0.000 0.000 0.000 0.000 2.346 ENE 0.000 0.460 0.184 0.000 0.000 0.000 0.000 0.000 0.000 0.644 E 0.000 0.092 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.184 ESE 0.000 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.092 SE 0.000 0.184 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.230 SSE 0.000 0.368 0.138 0.000 0.000 0.000 0.000 0.000 0.000 0.506 S 0.000 0.414 0.230 0.000 0.000 0.000 0.000 0.000 0.000 0.644 SSW 0.000 0.184 1.472 0.000 0.000 0.000 0.000 0.000 0.000 1.656 SW 0.000 0.092 0.414 0.092 0.000 0.000 0.000 0.000 0.000 0.598 WSW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 W 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SUBTOTAL 0.000 2.530 5.382 0.368 0.000 0.000 0.000 0.000 0.000 8.280 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2174 TOTAL HOURS OF STABILITY CLASS G 180 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS G 180 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2174 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/04/04 MEAN WIND SPEED = 1.93 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 47 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS A (DELTA T<=-1.9 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.183 0.183 0.092 0.000 0.000 0.000 0.458 NNE 0.000 0.000 0.092 1.099 0.733 0.137 0.000 0.000 0.000 2.061 NE 0.000 0.000 0.137 0.641 0.321 0.092 0.000 0.000 0.000 1.191 ENE 0.000 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.092 E 0.000 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.092 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.000 0.092 0.000 0.000 0.000 0.000 0.000 0.092 SSE 0.000 0.000 0.046 0.092 0.000 0.000 0.000 0.000 0.000 0.137 S 0.000 0.000 0.046 0.183 0.183 0.000 0.000 0.000 0.000 0.412 SSW 0.000 0.000 0.046 0.366 0.366 0.000 0.000 0.000 0.000 0.779 SW 0.000 0.000 0.000 0.229 0.092 0.000 0.000 0.000 0.000 0.321 WSW 0.000 0.000 0.000 0.000 0.046 0.137 0.000 0.000 0.000 0.183 W 0.000 0.000 0.000 0.000 0.000 0.183 0.046 0.000 0.000 0.229 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.046 NW 0.000 0.000 0.000 0.000 0.000 0.137 0.000 0.000 0.000 0.137 NNW 0.000 0.000 0.046 0.000 0.321 0.092 0.000 0.000 0.000 0.458 SUBTOTAL 0.000 0.000 0.504 2.978 2.245 0.870 0.092 0.000 0.000 6.688 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS A 146 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS A 146 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 5.67 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 48 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS B (-1.9< DELTA T<=-1.7 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.046 0.229 0.137 0.000 0.000 0.000 0.000 0.412 NNE 0.000 0.000 0.137 0.229 0.275 0.046 0.000 0.000 0.000 0.687 NE 0.000 0.000 0.046 0.137 0.046 0.000 0.000 0.000 0.000 0.229 ENE 0.000 0.000 0.092 0.092 0.000 0.000 0.000 0.000 0.000 0.183 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.000 0.092 0.046 0.000 0.000 0.000 0.000 0.137 SSE 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.046 S 0.000 0.000 0.046 0.137 0.412 0.000 0.000 0.000 0.000 0.596 SSW 0.000 0.000 0.046 0.870 0.733 0.046 0.000 0.000 0.000 1.695 SW 0.000 0.000 0.137 0.412 0.137 0.046 0.000 0.000 0.000 0.733 WSW 0.000 0.000 0.000 0.092 0.046 0.046 0.000 0.000 0.000 0.183 W 0.000 0.000 0.046 0.000 0.000 0.137 0.046 0.000 0.000 0.229 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.000 0.000 0.000 0.183 0.046 0.000 0.000 0.000 0.229 NNW 0.000 0.000 0.000 0.000 0.275 0.092 0.000 0.000 0.000 0.366 SUBTOTAL 0.000 0.000 0.596 2.336 2.290 0.458 0.046 0.000 0.000 5.726 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS B 125 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS B 125 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 5.46 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 49 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS C (-1.7< DELTA T<=-1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.046 0.092 0.137 0.000 0.000 0.000 0.000 0.275 NNE 0.000 0.000 0.137 0.504 0.229 0.000 0.000 0.000 0.000 0.870 NE 0.000 0.000 0.092 0.137 0.000 0.000 0.000 0.000 0.000 0.229 ENE 0.000 0.000 0.137 0.046 0.000 0.000 0.000 0.000 0.000 0.183 E 0.000 0.000 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.092 ESE 0.000 0.000 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.092 SE 0.000 0.000 0.046 0.092 0.000 0.000 0.000 0.000 0.000 0.137 SSE 0.000 0.000 0.092 0.046 0.046 0.046 0.000 0.000 0.000 0.229 S 0.000 0.000 0.137 0.321 0.183 0.092 0.000 0.000 0.000 0.733 SSW 0.000 0.000 0.366 1.787 0.412 0.092 0.000 0.000 0.000 2.657 SW 0.000 0.000 0.275 0.733 0.092 0.000 0.000 0.000 0.000 1.099 WSW 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 W 0.000 0.000 0.000 0.046 0.092 0.046 0.046 0.000 0.000 0.229 WNW 0.000 0.000 0.000 0.046 0.046 0.092 0.000 0.000 0.000 0.183 NW 0.000 0.000 0.000 0.000 0.229 0.092 0.046 0.000 0.000 0.366 NNW 0.000 0.000 0.000 0.000 0.137 0.092 0.000 0.000 0.000 0.229 SUBTOTAL 0.000 0.000 1.512 3.848 1.603 0.596 0.092 0.000 0.000 7.650 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS C 167 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS C 167 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 4.96 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 50 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS D (-1.5< DELTA T<=-0.5 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.641 1.237 0.366 0.046 0.000 0.000 0.000 2.290 NNE 0.000 0.000 1.374 1.466 0.366 0.092 0.000 0.000 0.000 3.298 NE 0.000 0.000 0.733 0.275 0.046 0.000 0.000 0.000 0.000 1.054 ENE 0.000 0.000 0.183 0.137 0.000 0.000 0.000 0.000 0.000 0.321 E 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 ESE 0.000 0.046 0.183 0.000 0.000 0.000 0.000 0.000 0.000 0.229 SE 0.000 0.046 0.550 0.092 0.046 0.000 0.000 0.000 0.000 0.733 SSE 0.000 0.000 0.779 0.550 0.092 0.000 0.000 0.000 0.000 1.420 S 0.000 0.046 2.519 2.886 1.145 0.321 0.000 0.000 0.000 6.917 SSW 0.000 0.000 4.077 4.535 0.779 0.183 0.000 0.000 0.000 9.574 SW 0.000 0.092 1.924 1.832 0.458 0.092 0.000 0.000 0.000 4.398 WSW 0.000 0.000 0.412 0.412 0.275 0.046 0.000 0.000 0.000 1.145 W 0.000 0.000 0.137 0.183 0.412 0.137 0.000 0.000 0.000 0.870 WNW 0.000 0.046 0.229 0.275 0.229 0.275 0.000 0.000 0.000 1.054 NW 0.000 0.092 0.229 0.137 0.366 0.183 0.000 0.000 0.000 1.008 NNW 0.000 0.000 0.366 0.321 0.504 0.000 0.000 0.000 0.000 1.191 SUBTOTAL 0.000 0.366 14.384 14.338 5.085 1.374 0.000 0.000 0.000 35.547 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS D 776 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS D 776 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 4.04 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 51 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS E (-0.5< DELTA T<= 1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.641 2.703 0.962 0.046 0.000 0.000 0.000 0.000 4.352 NNE 0.000 0.733 2.840 0.504 0.046 0.000 0.000 0.000 0.000 4.123 NE 0.000 0.229 0.412 0.092 0.000 0.000 0.000 0.000 0.000 0.733 ENE 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.092 E 0.000 0.183 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.275 ESE 0.000 0.183 0.366 0.000 0.000 0.000 0.000 0.000 0.000 0.550 SE 0.000 0.137 0.366 0.000 0.000 0.000 0.000 0.000 0.000 0.504 SSE 0.000 0.275 0.641 0.321 0.046 0.000 0.000 0.000 0.000 1.283 S 0.000 0.229 1.099 0.458 0.550 0.092 0.000 0.000 0.000 2.428 SSW 0.000 0.229 2.840 1.237 0.366 0.046 0.000 0.000 0.000 4.718 SW 0.000 0.321 3.573 0.641 0.046 0.000 0.000 0.000 0.000 4.581 WSW 0.000 0.000 1.054 0.321 0.046 0.000 0.000 0.000 0.000 1.420 W 0.000 0.137 0.412 0.183 0.046 0.000 0.000 0.000 0.000 0.779 WNW 0.000 0.183 0.092 0.000 0.046 0.000 0.000 0.000 0.000 0.321 NW 0.000 0.183 0.412 0.366 0.000 0.000 0.000 0.000 0.000 0.962 NNW 0.000 0.183 1.191 0.412 0.183 0.000 0.000 0.000 0.000 1.970 SUBTOTAL 0.000 3.894 18.140 5.497 1.420 0.137 0.000 0.000 0.000 29.088 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS E 635 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS E 635 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 2.73 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 52 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS F ( 1.5< DELTA T<= 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.412 1.420 0.229 0.000 0.000 0.000 0.000 0.000 2.061 NNE 0.000 0.687 3.023 0.000 0.000 0.000 0.000 0.000 0.000 3.710 NE 0.000 0.733 0.779 0.000 0.000 0.000 0.000 0.000 0.000 1.512 ENE 0.000 0.550 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.550 E 0.000 0.183 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.275 ESE 0.000 0.366 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.412 SE 0.000 0.412 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.458 SSE 0.000 0.275 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.321 S 0.000 0.321 0.137 0.046 0.000 0.000 0.000 0.000 0.000 0.504 SSW 0.000 0.183 1.054 0.046 0.000 0.000 0.000 0.000 0.000 1.283 SW 0.000 0.092 0.733 0.046 0.000 0.000 0.000 0.000 0.000 0.870 WSW 0.000 0.046 0.504 0.000 0.000 0.000 0.000 0.000 0.000 0.550 W 0.000 0.046 0.183 0.000 0.000 0.000 0.000 0.000 0.000 0.229 WNW 0.000 0.046 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.137 NW 0.000 0.046 0.137 0.046 0.000 0.000 0.000 0.000 0.000 0.229 NNW 0.000 0.092 0.458 0.046 0.000 0.000 0.000 0.000 0.000 0.596 SUBTOTAL 0.000 4.489 8.749 0.458 0.000 0.000 0.000 0.000 0.000 13.697 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS F 299 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS F 299 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 1.83 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 53 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS G (DELTA T > 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT APR 1, 2024 - JUN 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NNE 0.000 0.046 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.092 NE 0.000 0.092 0.092 0.000 0.000 0.000 0.000 0.000 0.000 0.183 ENE 0.000 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.137 E 0.000 0.092 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.137 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SSE 0.000 0.092 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.137 S 0.000 0.092 0.275 0.000 0.000 0.000 0.000 0.000 0.000 0.366 SSW 0.000 0.092 0.366 0.000 0.000 0.000 0.000 0.000 0.000 0.458 SW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 WSW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 W 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NNW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 SUBTOTAL 0.000 0.641 0.962 0.000 0.000 0.000 0.000 0.000 0.000 1.603 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2183 TOTAL HOURS OF STABILITY CLASS G 35 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS G 35 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2183 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/07/16 MEAN WIND SPEED = 1.67 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 54 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS A (DELTA T<=-1.9 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.454 0.272 0.000 0.000 0.000 0.000 0.726 NNE 0.000 0.000 0.091 1.816 0.817 0.182 0.000 0.000 0.000 2.905 NE 0.000 0.000 0.045 0.999 0.272 0.045 0.000 0.000 0.000 1.362 ENE 0.000 0.000 0.045 0.045 0.000 0.000 0.000 0.000 0.000 0.091 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.045 0.045 0.000 0.000 0.000 0.000 0.000 0.091 SSE 0.000 0.000 0.136 0.000 0.000 0.000 0.000 0.000 0.000 0.136 S 0.000 0.000 0.045 0.136 0.091 0.045 0.000 0.000 0.000 0.318 SSW 0.000 0.000 0.091 0.409 0.409 0.000 0.000 0.000 0.000 0.908 SW 0.000 0.000 0.091 0.409 0.091 0.000 0.000 0.000 0.000 0.590 WSW 0.000 0.000 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.045 W 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.045 WNW 0.000 0.000 0.000 0.000 0.045 0.045 0.000 0.000 0.000 0.091 NW 0.000 0.000 0.000 0.045 0.045 0.000 0.000 0.000 0.000 0.091 NNW 0.000 0.000 0.000 0.045 0.136 0.000 0.000 0.000 0.000 0.182 SUBTOTAL 0.000 0.000 0.635 4.403 2.224 0.318 0.000 0.000 0.000 7.581 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS A 167 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS A 167 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 5.02 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 55 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS B (-1.9< DELTA T<=-1.7 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.091 0.318 0.045 0.000 0.000 0.000 0.000 0.454 NNE 0.000 0.000 0.182 0.999 0.227 0.091 0.000 0.000 0.000 1.498 NE 0.000 0.000 0.545 0.272 0.000 0.000 0.000 0.000 0.000 0.817 ENE 0.000 0.000 0.272 0.045 0.000 0.000 0.000 0.000 0.000 0.318 E 0.000 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.091 ESE 0.000 0.000 0.045 0.091 0.000 0.000 0.000 0.000 0.000 0.136 SE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SSE 0.000 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.045 S 0.000 0.000 0.000 0.227 0.091 0.091 0.000 0.000 0.000 0.409 SSW 0.000 0.000 0.136 1.044 0.136 0.000 0.000 0.000 0.000 1.316 SW 0.000 0.000 0.409 0.227 0.045 0.000 0.000 0.000 0.000 0.681 WSW 0.000 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.091 W 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.045 WNW 0.000 0.000 0.045 0.136 0.000 0.000 0.000 0.000 0.000 0.182 NW 0.000 0.000 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.045 NNW 0.000 0.000 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.045 SUBTOTAL 0.000 0.000 1.952 3.404 0.635 0.182 0.000 0.000 0.000 6.173 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS B 136 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS B 136 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 4.27 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 56 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS C (-1.7< DELTA T<=-1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.182 0.363 0.045 0.000 0.000 0.000 0.000 0.590 NNE 0.000 0.000 0.409 0.681 0.000 0.000 0.000 0.000 0.000 1.089 NE 0.000 0.000 0.318 0.136 0.045 0.000 0.000 0.000 0.000 0.499 ENE 0.000 0.000 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.182 E 0.000 0.000 0.136 0.000 0.000 0.000 0.000 0.000 0.000 0.136 ESE 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.045 SE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SSE 0.000 0.000 0.272 0.045 0.000 0.000 0.000 0.000 0.000 0.318 S 0.000 0.000 0.091 0.363 0.045 0.000 0.000 0.000 0.000 0.499 SSW 0.000 0.000 0.454 1.180 0.000 0.000 0.000 0.000 0.000 1.634 SW 0.000 0.000 0.454 0.272 0.045 0.000 0.000 0.000 0.000 0.772 WSW 0.000 0.000 0.136 0.045 0.000 0.000 0.000 0.000 0.000 0.182 W 0.000 0.000 0.000 0.045 0.045 0.000 0.000 0.000 0.000 0.091 WNW 0.000 0.000 0.045 0.091 0.045 0.000 0.000 0.000 0.000 0.182 NW 0.000 0.000 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.045 NNW 0.000 0.000 0.045 0.045 0.045 0.000 0.000 0.000 0.000 0.136 SUBTOTAL 0.000 0.000 2.769 3.268 0.363 0.000 0.000 0.000 0.000 6.400 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS C 141 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS C 141 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 3.75 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 57 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS D (-1.5< DELTA T<=-0.5 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 1.226 1.044 0.136 0.045 0.000 0.000 0.000 2.451 NNE 0.000 0.000 1.861 2.951 1.816 0.363 0.000 0.000 0.000 6.990 NE 0.000 0.000 1.316 0.363 0.091 0.000 0.000 0.000 0.000 1.770 ENE 0.000 0.000 0.318 0.409 0.000 0.000 0.000 0.000 0.000 0.726 E 0.000 0.000 0.363 0.136 0.091 0.000 0.000 0.000 0.000 0.590 ESE 0.000 0.000 0.363 0.091 0.091 0.000 0.000 0.000 0.000 0.545 SE 0.000 0.091 0.409 0.136 0.045 0.000 0.000 0.000 0.000 0.681 SSE 0.000 0.045 1.180 0.454 0.000 0.000 0.000 0.000 0.000 1.680 S 0.000 0.091 2.814 2.951 0.635 0.908 0.000 0.000 0.000 7.399 SSW 0.000 0.045 3.677 2.769 0.363 0.182 0.000 0.000 0.000 7.036 SW 0.000 0.091 1.180 0.590 0.182 0.136 0.000 0.000 0.000 2.179 WSW 0.000 0.136 0.681 0.182 0.045 0.000 0.000 0.000 0.000 1.044 W 0.000 0.000 0.227 0.136 0.091 0.000 0.000 0.000 0.000 0.454 WNW 0.000 0.045 0.182 0.045 0.091 0.045 0.000 0.000 0.000 0.409 NW 0.000 0.000 0.182 0.136 0.000 0.000 0.000 0.000 0.000 0.318 NNW 0.000 0.045 0.409 0.318 0.091 0.000 0.000 0.000 0.000 0.862 SUBTOTAL 0.000 0.590 16.387 12.710 3.768 1.680 0.000 0.000 0.000 35.134 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS D 774 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS D 774 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 3.89 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 58 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS E (-0.5< DELTA T<= 1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.726 5.356 1.044 0.045 0.000 0.000 0.000 0.000 7.172 NNE 0.000 0.953 4.222 1.180 0.136 0.000 0.000 0.000 0.000 6.491 NE 0.000 0.409 0.409 0.045 0.000 0.000 0.000 0.000 0.000 0.862 ENE 0.000 0.227 0.409 0.000 0.000 0.000 0.000 0.000 0.000 0.635 E 0.000 0.091 0.409 0.045 0.000 0.000 0.000 0.000 0.000 0.545 ESE 0.000 0.091 0.136 0.000 0.000 0.000 0.000 0.000 0.000 0.227 SE 0.000 0.136 0.182 0.045 0.000 0.000 0.000 0.000 0.000 0.363 SSE 0.000 0.091 0.363 0.227 0.000 0.000 0.000 0.000 0.000 0.681 S 0.000 0.091 1.316 0.182 0.000 0.000 0.000 0.000 0.000 1.589 SSW 0.000 0.363 2.587 0.318 0.000 0.000 0.000 0.000 0.000 3.268 SW 0.000 0.045 1.634 0.318 0.000 0.000 0.000 0.000 0.000 1.997 WSW 0.000 0.272 0.590 0.182 0.000 0.000 0.000 0.000 0.000 1.044 W 0.000 0.182 0.590 0.045 0.045 0.000 0.000 0.000 0.000 0.862 WNW 0.000 0.363 0.363 0.000 0.000 0.000 0.000 0.000 0.000 0.726 NW 0.000 0.363 0.590 0.000 0.000 0.000 0.000 0.000 0.000 0.953 NNW 0.000 0.772 1.589 0.136 0.045 0.000 0.000 0.000 0.000 2.542 SUBTOTAL 0.000 5.175 20.744 3.768 0.272 0.000 0.000 0.000 0.000 29.959 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS E 660 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS E 660 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 2.33 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 59 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS F ( 1.5< DELTA T<= 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.227 2.133 0.091 0.045 0.000 0.000 0.000 0.000 2.497 NNE 0.000 1.362 4.085 0.136 0.000 0.000 0.000 0.000 0.000 5.583 NE 0.000 0.953 0.908 0.000 0.000 0.000 0.000 0.000 0.000 1.861 ENE 0.000 0.272 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.454 E 0.000 0.272 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.272 ESE 0.000 0.227 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.272 SE 0.000 0.182 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.227 SSE 0.000 0.136 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.182 S 0.000 0.091 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.182 SSW 0.000 0.091 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.272 SW 0.000 0.045 0.045 0.045 0.000 0.000 0.000 0.000 0.000 0.136 WSW 0.000 0.000 0.136 0.000 0.000 0.000 0.000 0.000 0.000 0.136 W 0.000 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.045 WNW 0.000 0.045 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.136 NW 0.000 0.000 0.409 0.000 0.000 0.000 0.000 0.000 0.000 0.409 NNW 0.000 0.091 0.272 0.000 0.000 0.000 0.000 0.000 0.000 0.363 SUBTOTAL 0.000 3.995 8.715 0.272 0.045 0.000 0.000 0.000 0.000 13.028 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS F 287 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS F 287 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 1.80 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 60 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS G (DELTA T > 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT JUL 1, 2024 - SEP 30, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.136 0.000 0.000 0.000 0.000 0.000 0.000 0.136 NNE 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.091 NE 0.000 0.227 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.272 ENE 0.000 0.182 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.227 E 0.000 0.045 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.091 ESE 0.000 0.227 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.272 SE 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.045 SSE 0.000 0.272 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.272 S 0.000 0.045 0.136 0.000 0.000 0.000 0.000 0.000 0.000 0.182 SSW 0.000 0.045 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.091 SW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WSW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 W 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.045 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.045 NNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SUBTOTAL 0.000 1.226 0.499 0.000 0.000 0.000 0.000 0.000 0.000 1.725 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2203 TOTAL HOURS OF STABILITY CLASS G 38 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS G 38 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2203 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2024/10/02 MEAN WIND SPEED = 1.43 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 61 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS A (DELTA T<=-1.9 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.091 0.319 0.091 0.000 0.000 0.000 0.501 NNE 0.000 0.000 0.000 0.865 0.728 0.273 0.000 0.000 0.000 1.866 NE 0.000 0.000 0.228 0.728 0.046 0.091 0.000 0.000 0.000 1.092 ENE 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ESE 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 SE 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 SSE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 S 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.046 SSW 0.000 0.000 0.046 0.046 0.091 0.000 0.000 0.000 0.000 0.182 SW 0.000 0.000 0.000 0.046 0.091 0.000 0.000 0.000 0.000 0.137 WSW 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 W 0.000 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.046 WNW 0.000 0.000 0.000 0.000 0.000 0.137 0.000 0.000 0.000 0.137 NW 0.000 0.000 0.000 0.000 0.046 0.137 0.000 0.000 0.000 0.182 NNW 0.000 0.000 0.000 0.000 0.228 0.228 0.000 0.000 0.000 0.455 SUBTOTAL 0.000 0.000 0.410 1.821 1.548 1.001 0.046 0.000 0.000 4.825 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS A 106 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS A 106 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 5.86 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 62 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS B (-1.9< DELTA T<=-1.7 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.182 0.137 0.046 0.000 0.000 0.000 0.364 NNE 0.000 0.000 0.091 0.228 0.091 0.137 0.000 0.000 0.000 0.546 NE 0.000 0.000 0.228 0.501 0.046 0.000 0.000 0.000 0.000 0.774 ENE 0.000 0.000 0.137 0.091 0.000 0.000 0.000 0.000 0.000 0.228 E 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 ESE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SSE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 S 0.000 0.000 0.046 0.000 0.000 0.046 0.000 0.000 0.000 0.091 SSW 0.000 0.000 0.000 0.046 0.182 0.046 0.000 0.000 0.000 0.273 SW 0.000 0.000 0.000 0.137 0.091 0.000 0.046 0.000 0.000 0.273 WSW 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 W 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 WNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 NW 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 NNW 0.000 0.000 0.000 0.000 0.091 0.091 0.000 0.000 0.000 0.182 SUBTOTAL 0.000 0.000 0.501 1.183 0.637 0.501 0.046 0.000 0.000 2.868 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS B 63 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS B 63 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 5.45 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 63 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS C (-1.7< DELTA T<=-1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.000 0.000 0.091 0.091 0.000 0.000 0.000 0.000 0.182 NNE 0.000 0.000 0.091 0.865 0.182 0.182 0.000 0.000 0.000 1.320 NE 0.000 0.000 0.364 0.182 0.000 0.000 0.000 0.000 0.000 0.546 ENE 0.000 0.000 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.182 E 0.000 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.091 ESE 0.000 0.000 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.137 SE 0.000 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.091 SSE 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 S 0.000 0.000 0.000 0.000 0.091 0.046 0.000 0.000 0.000 0.137 SSW 0.000 0.000 0.046 0.501 0.273 0.000 0.000 0.000 0.000 0.819 SW 0.000 0.000 0.137 0.410 0.091 0.046 0.000 0.000 0.000 0.683 WSW 0.000 0.000 0.000 0.046 0.046 0.046 0.000 0.000 0.000 0.137 W 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WNW 0.000 0.000 0.000 0.046 0.091 0.000 0.000 0.000 0.000 0.137 NW 0.000 0.000 0.000 0.046 0.000 0.182 0.000 0.000 0.000 0.228 NNW 0.000 0.000 0.000 0.000 0.000 0.046 0.000 0.000 0.000 0.046 SUBTOTAL 0.000 0.000 1.138 2.185 0.865 0.546 0.000 0.000 0.000 4.734 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS C 104 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS C 104 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 4.94 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 64 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS D (-1.5< DELTA T<=-0.5 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.046 0.637 0.865 1.593 0.728 0.000 0.000 0.000 3.869 NNE 0.000 0.046 1.365 2.594 1.548 0.228 0.000 0.000 0.000 5.781 NE 0.000 0.091 1.411 0.410 0.091 0.046 0.000 0.000 0.000 2.048 ENE 0.000 0.091 0.228 0.046 0.000 0.000 0.000 0.000 0.000 0.364 E 0.000 0.091 0.364 0.000 0.000 0.000 0.000 0.000 0.000 0.455 ESE 0.000 0.000 0.228 0.000 0.000 0.000 0.000 0.000 0.000 0.228 SE 0.000 0.000 0.273 0.000 0.000 0.000 0.000 0.000 0.000 0.273 SSE 0.000 0.046 0.182 0.046 0.000 0.000 0.000 0.000 0.000 0.273 S 0.000 0.046 1.092 1.365 0.865 0.046 0.000 0.000 0.000 3.414 SSW 0.000 0.182 2.412 4.142 1.593 0.501 0.000 0.000 0.000 8.830 SW 0.000 0.046 2.412 2.003 0.592 0.137 0.000 0.000 0.000 5.189 WSW 0.000 0.046 0.319 0.000 0.091 0.091 0.000 0.000 0.000 0.546 W 0.000 0.046 0.091 0.137 0.000 0.137 0.000 0.000 0.000 0.410 WNW 0.000 0.000 0.046 0.091 0.137 0.091 0.000 0.000 0.000 0.364 NW 0.000 0.000 0.182 0.319 0.410 0.455 0.000 0.000 0.000 1.365 NNW 0.000 0.091 0.364 0.774 1.001 0.501 0.000 0.000 0.000 2.731 SUBTOTAL 0.000 0.865 11.607 12.790 7.920 2.959 0.000 0.000 0.000 36.140 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS D 796 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS D 794 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 4.50 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 65 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS E (-0.5< DELTA T<= 1.5 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.956 1.684 1.365 0.046 0.000 0.000 0.000 0.000 4.051 NNE 0.000 1.047 3.914 1.092 0.501 0.000 0.000 0.000 0.000 6.554 NE 0.000 0.455 0.546 0.319 0.000 0.000 0.000 0.000 0.000 1.320 ENE 0.000 0.091 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.137 E 0.000 0.228 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.364 ESE 0.000 0.091 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.137 SE 0.000 0.182 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.319 SSE 0.000 0.137 0.364 0.000 0.046 0.000 0.000 0.000 0.000 0.546 S 0.000 0.546 0.819 0.273 0.182 0.000 0.000 0.000 0.000 1.821 SSW 0.000 0.228 3.186 1.548 0.546 0.091 0.000 0.000 0.000 5.599 SW 0.000 0.364 2.412 0.637 0.137 0.046 0.000 0.000 0.000 3.596 WSW 0.000 0.046 0.546 0.182 0.046 0.000 0.000 0.000 0.000 0.819 W 0.000 0.091 0.319 0.319 0.000 0.000 0.000 0.000 0.000 0.728 WNW 0.000 0.046 0.273 0.137 0.046 0.000 0.000 0.000 0.000 0.501 NW 0.000 0.000 0.455 0.683 0.046 0.046 0.000 0.000 0.000 1.229 NNW 0.000 0.228 0.637 0.683 0.091 0.000 0.000 0.000 0.000 1.639 SUBTOTAL 0.000 4.734 15.521 7.237 1.684 0.182 0.000 0.000 0.000 29.358 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS E 645 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS E 645 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 2.85 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 66 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS F ( 1.5< DELTA T<= 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.501 1.639 0.091 0.000 0.000 0.000 0.000 0.000 2.230 NNE 0.000 1.502 5.599 0.364 0.000 0.000 0.000 0.000 0.000 7.465 NE 0.000 0.683 1.502 0.046 0.000 0.000 0.000 0.000 0.000 2.230 ENE 0.000 0.455 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.546 E 0.000 0.182 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.228 ESE 0.000 0.319 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.364 SE 0.000 0.182 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.228 SSE 0.000 0.182 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.319 S 0.000 0.137 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.273 SSW 0.000 0.182 1.229 0.000 0.000 0.000 0.000 0.000 0.000 1.411 SW 0.000 0.000 1.092 0.091 0.000 0.000 0.000 0.000 0.000 1.183 WSW 0.000 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.091 W 0.000 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.091 WNW 0.000 0.000 0.137 0.046 0.000 0.000 0.000 0.000 0.000 0.182 NW 0.000 0.046 0.091 0.046 0.000 0.000 0.000 0.000 0.000 0.182 NNW 0.000 0.273 0.546 0.182 0.000 0.000 0.000 0.000 0.000 1.001 SUBTOTAL 0.000 4.643 12.517 0.865 0.000 0.000 0.000 0.000 0.000 18.025 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS F 396 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS F 396 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 1.93 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

Sequoyah Nuclear Plant Units 1 and 2 2024 Annual Radioactive Effluent Release Report Meteorological Data 67 JOINT PERCENTAGE FREQUENCIES OF WIND SPEED BY WIND DIRECTION FOR STABILITY CLASS G (DELTA T > 4.0 C/100 M)

SEQUOYAH NUCLEAR PLANT OCT 1, 2024 - DEC 31, 2024 WIND WIND SPEED(MPH)

DIRECTION CALM 0.60-1.40 1.41-3.40 3.41-5.40 5.41-7.40 7.41-12.40 12.41-18.40 18.41-24.40 >=24.41 TOTAL N 0.000 0.046 0.137 0.000 0.000 0.000 0.000 0.000 0.000 0.182 NNE 0.000 0.228 1.001 0.000 0.000 0.000 0.000 0.000 0.000 1.229 NE 0.000 0.319 0.728 0.000 0.000 0.000 0.000 0.000 0.000 1.047 ENE 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.046 E 0.000 0.273 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.273 ESE 0.000 0.091 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.091 SE 0.000 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.182 SSE 0.000 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.182 S 0.000 0.137 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.182 SSW 0.000 0.137 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.319 SW 0.000 0.000 0.182 0.000 0.000 0.000 0.000 0.000 0.000 0.182 WSW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 W 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 WNW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 NW 0.000 0.000 0.046 0.000 0.000 0.000 0.000 0.000 0.000 0.046 NNW 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 0.000 SUBTOTAL 0.000 1.639 2.412 0.000 0.000 0.000 0.000 0.000 0.000 4.051 TOTAL HOURS OF VALID STABILITY OBSERVATIONS 2199 TOTAL HOURS OF STABILITY CLASS G 89 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY CLASS G 89 TOTAL HOURS OF VALID WIND DIRECTION-WIND SPEED-STABILITY OBSERVATIONS 2197 TOTAL HOURS CALM 0 METEOROLOGICAL FACILITY: SEQUOYAH NUCLEAR PLANT STABILITY BASED ON DELTA-T BETWEEN 9.25 AND 45.99 METERS WIND SPEED AND DIRECTION MEASURED AT 9.73 METER LEVEL DATE PRINTED: 2025/01/08 MEAN WIND SPEED = 1.61 NOTE: TOTALS AND SUBTOTALS ARE OBTAINED FROM UNROUNDED NUMBERS

ML25113A037

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