Text

Annual Radioactive Effluent Release Report (ARERR)
	ML25113A044
Person / Time
Site:	Grand Gulf
Issue date:	04/23/2025
From:	Hardy J; Entergy Operations
To:	; Office of Nuclear Reactor Regulation, Document Control Desk
References
	GNR02025-00011
	Download: ML25113A044 (1)
	v • d • e

) entergy GNRO2025-00011 April 23, 2025 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, D.C. 20555-0001 Entergy Operations, Inc.

P.O. Box 756 Port Gibson, Mississippi 39150 Jeffery Hardy Manager Regulatory Assurance Grand Gulf Nuclear Station Tel: 802-380-5124 GGNS TS 5.6.2

SUBJECT:

Grand Gulf Nuclear Station Annual Radioactive Effluent Release Report (ARERR)

Grand Gulf Nuclear Station, Unit 1 Docket No. 50-416 License No. NPF-29 In accordance with Grand Gulf Nuclear Station Unit 1 Technical Specification 5.6.2, attached is the Annual Radioactive Effluent Release Report for the time-period of January 1, 2024 through December 31, 2024.

There are no commitments contained in this submittal. If you have any questions or need additional information, please contact me at 802-380-5124.

Attachment:

1. Annual Radioactive Effluent Release Report

GNRO2025-00011 Page 2 of 2 cc:

NRC Senior Resident Inspector Grand Gulf Nuclear Station Port Gibson, MS 39150 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001 State Health Officer, Mississippi Department of Health GNRO2025-00011 Annual Radioactive Effluent Release Report

E) entergy Grand Gulf Nuclear Station Annual Radioactive Effluent Release Report 2024 Document Number: GNRO2025-00011

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 1 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station TABLE OF CONTENTS 1.0 LIST OF ACRONYMS AND DEFINITIONS................................................................................ 3 2.0 EXECUTIVE

SUMMARY

............................................................................................................ 5 2.1 Comparison to Regulatory Limits.................................................................................... 6

3.0 INTRODUCTION

........................................................................................................................ 8 3.1 About Nuclear Power...................................................................................................... 8 3.2 About Radiation Dose................................................................................................... 10 3.3 About Dose Calculation................................................................................................ 12 4.0 DOSE ASSESSMENT FOR PLANT OPERATIONS................................................................. 14 4.1 Regulatory Limits.......................................................................................................... 14 4.2 Regulatory Limits for Gaseous Effluent Doses:............................................................. 14 4.3 Regulatory Limits for Liquid Effluent Doses................................................................... 15 4.4 40 CFR 190 Regulatory Dose Limits for a Member of the Public.................................. 16 4.5 Onsite Doses (Within Site Boundary)............................................................................ 16 5.0 SUPPLEMENTAL INFORMATION........................................................................................... 17 5.1 Gaseous Batch Releases............................................................................................. 17 5.2 Liquid Batch Releases.................................................................................................. 17 5.3 Abnormal Releases...................................................................................................... 17 5.4 Non-routine Planned Discharge.................................................................................... 17 5.5 Land Use Census Changes.......................................................................................... 19 5.6 Meteorological Data...................................................................................................... 19 5.7 Effluent Radiation Monitors Out of Service Greater Than 30 Days................................ 19 5.8 Offsite Dose Calculation Manual (ODCM) Changes...................................................... 19

5. 9 Process Control Program (PCP) Changes.................................................................... 19 5.1 O Radioactive Waste Treatment System Changes........................................................... 19 5.11 Other Supplemental Information................................................................................... 19 6.0 NEI 07-07 ONSITE RADIOLOGICAL GROUNDWATER MONITORING PROGRAM............... 21 6.1 Voluntary Notification.................................................................................................... 25 7.0 BIBLIOGRAPHY...................................................................................................................... 26 TABLES Table 1, Grand Gulf Nuclear Station Unit 1 Dose Summary................................................................... 6 Table 2, Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for GGNS.................................. 7 Table 3, Onsite Doses (Within Site Boundary)..................................................................................... 16 Table 4, Groundwater Protection Program Monitoring Well Sample Schedule..................................... 22 Table 5, Groundwater Protection Program Monitoring Well Tritium Results......................................... 24 Table 6, Gaseous Effluents Summation of All Releases GGNS.......................................................... 27 Table 7, Gaseous Effluents-Ground Level Release Continuous Mode GGNS................................. 28 Table 8, Liquid Effluents - Summation of All Releases GGNS............................................................ 29

Annual Radioactive Effluent Release Report I YEAR: 2024 I

Page 2 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station Table 9, Batch Mode Liquid Effluents GGNS....................................................................................... 30 Table 10, Types of Solid Waste Summary GGNS................................................................................ 31 Table 11, Major Nuclides GGNS.......................................................................................................... 31 Table 12, Solid Waste Disposition GGNS............................................................................................ 33 Table 13, Irradiated Fuel Shipments Disposition GGNS....................................................................... 33 FIGURES Figure 1, Pressurized Water Reactor (PWR) [1]..................................................................................... 8 Figure 2, Boiling Water Reactor (BWR) [2]............................................................................................. 9 Figure 3, Sources of Radiation Exposure (NCRP Report No. 160) [3].................................................. 1 O Figure 4, Potential exposure pathways to Members of the Public due to Plant Operations [6]............. 12 Figure 5, Non-Routine Batch Release.................................................................................................. 18 ATTACHMENTS, ARERR Release Summary Tables (RG-1.21 Tables)................................................... 27, Solid Waste Information................................................................................................ 31

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 3 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station 1.0 LIST OF ACRONYMS AND DEFINITIONS

1.

Alpha Particle (a): A charged particle emitted from the nucleus of an atom having a mass and charge equal in magnitude of a helium nucleus.

2.

BWR: Boiling Water Reactor

3.

Composite Sample: A series of single collected portions (aliquots) analyzed as one sample. The aliquots making up the sample are collected at time intervals that are very short compared to the composite period.

4.

Control: A sampling station in a location not likely to be affected by plant effluents due to its distance and/or direction from the Plant.

5.

Counting Error: An estimate of the two-sigma uncertainty associated with the sample results based on total counts accumulated.

6.

Curie (Ci): A measure of radioactivity; equal to 3.7 x 1010 disintegrations per second, or 2.22 x 1012 disintegrations per minute.

7.

Direct Radiation Monitoring: The measurement of radiation dose at various distances from the plant is assessed using thermoluminescent dosimeters (TLDs), optically stimulated luminescent dosimeters (OSLDs), and/or pressurized ionization chambers.

8.

Grab Sample: A single discrete sample drawn at one point in time.

9.

Indicator: A sampling location that is potentially affected by plant effluents due to its proximity and/or direction from the plant.

10.

Ingestion Pathway: The ingestion pathway includes milk, fish, drinking water and garden produce. Also sampled (under special circumstances) are other media such as vegetation or animal products when additional information about particular radionuclides is needed.

11.

ISFSI: Independent Spent Fuel Storage Installation

12.

LLD: Lower Limit of Detection. An a priori measure of the detection capability of a radiochemistry measurement based on instrument setup, calibration, background, decay time, and sample volume. An LLD is expressed as an activity concentration. The MDA is used for reporting results. LLD are specified by a regulator, such as the NRC and are typically listed in the ODCM.

13.

MDA: Minimum Detectable Activity. For radiochemistry instruments, the MDA is the a posteriori minimum concentration that a counting system detects. The smallest concentration or activity of radioactive material in a sample that will yield a net count above instrument background and that is detected with 95%

probability, with only 5% probability of falsely concluding that a blank observation represents a true signal.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 4 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station

14.

MDC: Minimum Detectable Concentration. Essentially synonymous with MDA for the purposes of radiological monitoring.

15.

Mean: The sum of all of the values in a distribution divided by the number of values in the distribution, synonymous with average.

16.

Microcurie (µCi): 3.7 x 104 disintegrations per second, or 2.22 x106 disintegrations per minute.

17.

millirem (mrem): 1/1000 rem; a unit of radiation dose equivalent in tissue.

18.

Milliroentgen (mR): 1/1000 Roentgen; a unit of exposure to X-or gamma radiation.

19.

N/A: Not Applicable

20.

NEI: Nuclear Energy Institute

21.

NRC: Nuclear Regulatory Commission

22.

ODCM: Offsite Dose Calculation Manual

23.

OSLO: Optically Stimulated Luminescence Dosimeter

24.

Protected Area: A 10 CFR 73 security term is an area encompassed by physical barriers and to which access is controlled for security purposes. The fenced area immediately surrounding the plant and around ISFSI are commonly classified by the licensee as "Protected areas." Access to the protected area requires a security badge or escort.

25.

PWR: Pressurized Water Reactor

26.

REC: Radiological Effluent Control

27.

REMP: Radiological Environmental Monitoring Program

28.

Restricted Area: A 10 CFRR 20 defined term where access to which is limited by the licensee for the purpose of protecting individuals against undue risks from exposure to radiation and radioactive materials.

29.

TEDE: Total Effective Dose Equivalent (TEDE) means the sum of the effective dose equivalent (for external exposures) and the committed effective dose equivalent (for internal exposures).

30.

TLD: Thermoluminescent Dosimeter 31.

TRM: Technical Requirements Manual

32.

TS: Technical Specification

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 5 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station

33.

Unrestricted Area: An area, access to which is neither limited nor controlled by the licensee.

2.0 EXECUTIVE

SUMMARY

Grand Gulf Nuclear Station (GGNS) Radiological Effluent Control (REC) Program was established to limit the quantities of radioactive material that may be released based on calculated radiation doses or dose rates. Dose to Members of the Public due to radioactive materials released from the plant is limited by Technical Specifications, 1 O CFR 20, and by 40 CFR 190. Operational doses to the public during 2024 were calculated to be within the limits required by regulation and compared to other sources of radiation dose and pose no health hazard. These doses are summarized and compared to the regulatory limits in Section 2.1 Comparison to Regulatory Limits below.

The Annual Radioactive Effluent Release Report (ARERR) is published per REC requirements and provides data related to plant operation, including: quantities of radioactive materials released in liquid and gaseous effluents; radiation doses to members of the public; solid radioactive waste shipped offsite for processing or direct disposal; and other information as required by site licensing documents.

In 2024, the gaseous effluent dose assessments for locations from the Land Use Census showed that the critical receptor for Grand Gulf Nuclear Station is a Child, due to Ground Plane, Inhalation, Garden Vegetation and Grass-Cow-Meat pathways in the southwest sector at 0.89 miles. The maximum Annual Organ Dose calculated for this receptor was 5.58E-02 mrem to the Child Thyroid.

The maximum dose calculated to any organ due to radioactive liquid effluents was 3.64E-01 mrem to the Adult Liver due to liquid releases.

Solid radioactive waste shipped offsite for processing or direct disposal included 6.14E+04 Curies and 9.98E+02 m3, shipped in 52 shipments.

In addition to monitoring radioactive effluents, GGNS has a Radiological Environmental Monitoring Program (REMP) that monitors for levels of radiation and radioactive materials in the local environment. Data from the REMP is published in the Annual Radiological Environmental Operating Report (AREOR).

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 6 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station 2.1 Comparison to Regulatory Limits During 2024 all solid, liquid, and gaseous radioactive effluents from Grand Gulf Nuclear Station were well below regulatory limits, as summarized in Table 1 and Table 2.

Table 1, Grand Gulf Nuclear Station Unit 1 Dose Summary1 Quarter 1 Quarter 2 Quarter 3 Quarter 4 Liquid Effluents Limit 1.5 mrem 1.5 mrem 1.5 mrem 1.5 mrem Total Body Dose 1.09E-01 5.00E-02 1.39E-02 1.28E-02

% Of Limit 7.27E+00 3.33E+00 9.27E-01 8.51 E-01 Limit 5 mrem 5 mrem 5 mrem 5mrem Maximum Organ Dose 2.33E-01 9.68E-02 3.0BE-02 2.21E-02

% Of Limit 4.66E+O0 1.94E+00 6.16E-01 4.42E-01 Gaseous Effluents Limit 5 mrad 5 mrad 5 mrad 5 mrad Gamma Air Dose 8.29E-02 1.09E-01 2.0?E-01 8.16E-02

% Of Limit 1.66E+00 2.19E+00 4.13E+00 1.63E+00 Limit 10 mrad 10 mrad 10 mrad 10 mrad Beta Air Dose 3.53E-02 5.34E-02 8.23E-02 3.95E-02

% Of Limit 3.53E-01 5.34E-01 8.23E-01 3.95E-01 Limit 7.5 mrem 7.5 mrem 7.5 mrem 7.5 mrem Maximum Organ Dose 1.42E-02 1.30E-02 1.14E-02 1.74E-02

% Of Limit 1.89E-01 1.74E-01 1.52E-01 2.33E-01 1 Table 1 demonstrates compliance with 10 CFR Part 50, App. I Limits.

2 Adult Liver 3 Child Thyroid Annual 3 mrem 1.77E-01 5.90E+00 10 mrem 3.64E-01 2 3.64E+00 10 mrad 4.81 E-01 4.81E+00 20 mrad 2.11E-01 1.06E+00 15 mrem 5.SBE-023 3.72E-01

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 7 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station Table 2, Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for GGNS Whole Body Thyroid Max Other Organ Gaseous1 5.31 E-01 5.58E-02 5.58E-02 Carbon-14 1.0?E+00 1.0?E+00 5.36E+00 Liquid

1. ??E-01 1.23E-03 3.64E-01 Direct Shine 0

0 0

Total Site Dose 1.78E+00 1.13E+00 5.78E+00 Total w/Other Nearby Facility2 N/A N/A N/A Limit 25 mrem 75 mrem 25 mrem

% of Limit 7.12E+00 1.S0E+00 2.31 E+01 1 Gaseous dose values in Table 2 include organ dose from Noble Gas, Iodine, Tritium, and particulates.

2 Other fuel cycle sources within 5 miles of the site are considered in this analysis.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 8 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station

3.0 INTRODUCTION

3.1 About Nuclear Power Commercial nuclear power plants are generally classified as either Boiling Water Reactors (BWRs) or Pressurized Water Reactors (PWRs), based on their design. A BWR includes a single coolant system where water used as reactor coolant boils as it passes through the core and the steam generated is used to turn the turbine generator for power production. A PWR, in contrast, includes two separate water systems: radioactive reactor coolant and a secondary system. Reactor coolant is maintained under high pressure, preventing boiling. The high-pressure coolant is passed through a heat exchanger called a steam generator where the secondary system water is boiled, and the steam is used to turn the turbine generator for power production.

Contoinment StNetl.ft Figure 1, Pressurized Water Reactor (PWR) [1]

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 9 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 3.1 (Continued)

Containment Structure Figure 2, Boiling Water Reactor (BWR) [2]

Electricity is generated by a nuclear power plant similarly to the way that electricity is generated at other conventional types of power plants, such as those powered by coal or natural gas. Water is boiled to generate steam; the steam turns a turbine that is attached to a generator and the steam is condensed back into water to be returned to the boiler. What makes nuclear power different from these other types of power plants is that the heat is generated by fission and decay reactions occurring within and around the core containing fissionable uranium (U-235).

Nuclear fission occurs when certain nuclides (primarily U-233, U-235, or Pu-239) absorb a neutron and break into several smaller nuclides (called fission products) as well as producing some additional neutrons.

Fission results in production of radioactive materials including gases and solids that must be contained to prevent release or treated prior to release. These effluents are generally treated by filtration and/or hold-up prior to release. Releases are generally monitored by sampling and by continuously indicating radiation monitors. The effluent release data is used to calculate doses in order to ensure that dose to the public due to plant operation remains within required limits.

Ann-ual Radioactive Effluent Release Report I YEAR: 2024 I Page 10 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station 3.2 About Radiation Dose Ionizing radiation, including alpha, beta, and gamma radiation from radioactive decay, has enough energy to break chemical bonds in tissues and result in damage to tissue or genetic material. The amount of ionization that will be generated by a given exposure to ionizing radiation is quantified as dose. Radiation dose is generally reported in units of millirem (mrem) in the US.

Space (background)

Computed tomograpliy (medical)

(24%)

Terrestrial (background)

(3%)

Nuclear medicine (medical)

{12%)

lnterventional fluoroscopy (medical)

(7%)

(5%)

Radon & thoron (background)

(37%)

Industrial

(<0.1%)

Occupational

(<0.1%)

Consumer Conventional radiographyffluoroscopy (medical)

(5%)

(2%)

Figure 3, Sources of Radiation Exposure (NCRP Report No. 160) [3]

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 11 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 3.2 (Continued)

The National Council on Radiation Protection (NCRP) has evaluated the population dose for the US and determined that the average individual is exposed to approximately 620 mrem per year [3]. There are many sources for radiation dose, ranging from natural background sources to medical procedures, air travel, and industrial processes. Approximately half (310 mrem) of the average exposure is due to natural sources of radiation including exposure to radon, cosmic radiation, and internal radiation and terrestrial due to naturally occurring radionuclides. The remaining 310 mrem of exposure is due to man-made sources of exposure, with the most significant contributors being medical (48% of total mrem per year) due to radiation used in various types of medical scans and treatments. Of the remaining 2%

of dose, most is due to consumer activities such as air travel, smoking cigarettes, and building materials. A small fraction of this 2% is due to industrial activities including generation of nuclear power.

Readers that are curious about common sources and effects of radiation dose that they may encounter can find excellent sources of information from the Health Physics Society, including the Radiation Fact Sheets [4], and from the US Nuclear Regulatory Commission website [5].

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 12 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 3.3 About Dose Calculation Concentrations of radioactive material in the environment resulting from plant operations are very small and it is not possible to determine doses directly using measured activities of environmental samples. To overcome this, dose calculations based on measured activities of effluent streams are used to model the dose impact for Members of the Public due to plant operation and effluents. There are several mechanisms that can result in dose to Members of the Public, including: Ingestion of radionuclides in food or water; Inhalation of radionuclides in air; Immersion in a plume of noble gases; and Direct Radiation from the ground, the plant or from an elevated plume.

Livestock products

Radiation o

Radionuclides

.... : Behavior of radionuclides Figure 4, Potential exposure pathways to Members of the Public due to Plant Operations [6]

Each plant has an Offsite Dose Calculation Manual (ODCM) that specifies the methodology used to obtain the doses in the Dose Assessment section of this report.

The dose assessment methodology in the ODCM is based on NRC Regulatory Guide 1.109 [7] and NUREG-0133 [8]. Doses are calculated by determining what the nuclide concentration will be in air, water, on the ground, or in food products based on plant effluent releases. Release points are continuously monitored to quantify what concentrations of nuclides are being released. For gaseous releases meteorological data is used to determine how much of the released activity will be present at a given location outside of the plant either deposited onto the ground or in gaseous form.

Intake patterns and nuclide bio-concentration factors are used to determine how much activity will be transferred into animal milk or meat. Finally, human ingestion factors and dose factors are used to determine how much activity will be consumed and how much dose the consumer will receive. Inhalation dose is calculated by determining the concentration of nuclides and how much air is breathed by the individual.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 13 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 3.3 (Continued)

For liquid releases, dilution and mixing factors are used to model the environmental concentrations in water. Drinking water pathways are modeled by determining the concentration of nuclides in the water at the point where the drinking water is sourced (e.g., taken from wells, rivers, or lakes). Fish and invertebrate pathways are determined by using concentration at the release point, bioaccumulation factors for the fish or invertebrate and an estimate of the quantity of fish consumed.

Every two years a Land Use Census is performed to determine what potential dose pathways currently exist within a five-mile radius around the plant, the area most affected by plant operations. The Annual Land Use Census identifies the locations of vegetable gardens, nearest residences, milk animals and meat animals. The data from the census is used to determine who is the likely to be most exposed to radiation dose as a result of plant operation.

There is significant uncertainty in dose calculation results, due to modeling dispersion of material released and bioaccumulation factors, as well as assumptions associated with consumption and land-use patterns. Even with these sources of uncertainty, the calculations do provide a reasonable estimate of the order of magnitude of the exposure. Conservative assumptions are made in the calculation inputs such as the number of various foods and water consumed, the amount of air inhaled, and the amount of direct radiation exposure from the ground or plume, such that the actual dose received are likely lower than the calculated dose. Even with the built-in conservatism, doses calculated for the maximum exposed individual due to plant operation are a very small fraction of the annual dose that is received due to other sources. The calculated doses due to plant effluents, along with REMP results, serve to provide assurance that radioactive effluents releases are not exceeding safety standards for the environment or people living near the plant.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 14 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station 4.0 DOSE ASSESSMENT FOR PLANT OPERATIONS 4.1 Regulatory Limits 4.2 Regulatory limits are detailed in station licensing documents such as the plant Technical Specifications (Sections 5.5.1, 5.5.4, 5.6.2, 5.6.3 of GGNS License Number NPF-29) and the Offsite Dose Calculation Manual (ODCM). These documents contain the limits to which GGNS must adhere. GGNS drives to maintain the philosophy to keep dose "as low as is reasonably achievable" (ALARA) and actions are taken to reduce the an:,ount of radiation released to the environment. Liquid and gaseous release data show that the dose from GGNS is well below the ODCM limits. The instantaneous concentration of liquid radioactive material released shall be limited to ten times the concentration specified in 1 O CFR 20, Appendix B, Table 2, Column 2, for radionuclides other than dissolved or entrained noble gases. For dissolved or entrained noble gases, the total concentration released shall be limited to 2.0 x 10-4 microcuries/ml.

The annual whole body, skin and organ dose was computed using the 2024 source term using the dose calculation methodology provided in the ODCM. The calculated doses due to gaseous effluents are used to demonstrate compliance with offsite dose limits are presented in Table 1, Grand Gulf Nuclear Station Unit 1 Dose Summary and Table 2, Total Annual Offsite-Dose Comparison to 40 CFR 190 Limits for GGNS.

Regulatory Limits for Gaseous Effluent Doses:

1.

Fission and activation gases:

a.

Noble gases dose rate due to radioactive materials released in gaseous effluents from the site to areas at and beyond the site boundary shall be limited to the following:

1)

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

2)

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

b.

Noble gas air dose due to noble gases released in gaseous effluents from each reactor unit, to areas at and beyond the site boundary shall be limited to the following:

1)

Quarterly a)

Less than or equal to 5 mrads gamma b)

Less than or equal to 1 O mrads beta

2)

Yearly a)

Less than or equal to 10 mrads gamma b)

Less than or equal to 20 mrads beta

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 15 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 4.2 (Continued) 4.3

2.

Iodine, tritium, and all radionuclides in particulate form with half-lives greater than 8 days.

a.

The dose rate for iodine-131, iodine-133, tritium, and all radionuclides in particulate form with half-lives greater than 8 days in gaseous effluents released from the site to areas at and beyond the site boundary shall be limited to the following:

1)

Less than or equal to 1500 mrem/yr to any organ

b.

The dose to a MEMBER OF THE PUBLIC from iodine-131, iodine-133, tritium, and all radionuclides in particulate form with half-lives greater than 8 days in gaseous effluents released from each reactor unit, to areas at and beyond the site boundary shall be limited to the following:

1)

Quarterly a)

Less than or equal to 7.5 mrem to any organ

2)

Yearly a)

Less than or equal to 15 mrem to any organ Regulatory Limits for Liquid Effluent Doses

1.

The dose or dose commitment to a MEMBER OF THE PUBLIC from radioactive materials in liquid effluents released from each reactor unit, to unrestricted areas shall be limited to the following:

a.

Quarterly

1)

Less than or equal to 1.5 mrem total body

2)

Less than or equal to 5 mrem critical organ

b.

Yearly

1)

Less than or equal to 3 mrem total body

2)

Less than or equal to 1 O mrem critical organ

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 16 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 4.4 4.5 40 CFR 190 Regulatory Dose Limits for a Member of the Public

1.

Total Dose (40 CFR 190)

a.

The annual (calendar year) dose or dose commitment to any MEMBER OF THE PUBLIC in the unrestricted area due to releases of radioactivity and to radiation from uranium fuel cycle sources shall be limited to the following:

1)

Less than or equal to 25 mrem, Total Body or any Organ except Thyroid.

2)

Less than or equal to 75 mrem, Thyroid.

Onsite Doses (Within Site Boundary)

GGNS classifies individuals within the site boundary as either occupationally exposed individuals or members of the public. This section evaluates dose to non-occupationally exposed workers and members of the public that may be onsite for various reasons. The report must include any other information as may be required by the Commission to estimate maximum potential annual radiation doses to the public resulting from effluent releases as required by 10 CFR 50.36a(a)(2). While within controlled or restricted areas, the limits from Sections 4.1 through 4.4 do not apply; however, 10 CFR 20.1301 dose limit of 100 mrem per year TEDE and dose rate limit of 2 mrem per hour from external sources continue to apply. Occupancy times within the controlled areas are generally sufficiently low to compensate for increase in the atmospheric dispersion factor above the site boundary. Groups of concern include Access Control personnel and Credit Union employees. Use of a conservative assumption of 2000 hour0.0231 days 0.556 hours 0.00331 weeks 7.61e-4 months s/year spent inside the site boundary by these groups conservatively represents the most-exposed individual.

Table 3, Onsite Doses (Within Site Boundary)

Approx.

Dose (mrem)

Location Sector Distance Occupancy (Miles)

(Hours)

Total Body Organ Energy Service NNW 0.5 2000 1.58E-02 2.48E-02 Centers Credit Union NW 0.18 2000 1.19E-01 1.88E-01 Doses calculated using GASPARI!, NRCDose3, Version 1.1.3. Adult working 2000 hours0.0231 days 0.556 hours 0.00331 weeks 7.61e-4 months per year. 2024 Daytime X/Q and D/Q was used. Plume, Ground Plane and Inhalation doses were considered. C-14 is included.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 17 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 5.0 SUPPLEMENTAL INFORMATION 5.1 Gaseous Batch Releases 5.1.1 GGNS Unit 1 Number of batch releases Total time period for a batch release 0

Maximum time period for a batch release 0

Average time period for a batch release 0

Minimum time period for a batch release 0

5.2 Liquid Batch Releases 5.2.1 GGNS Unit 1 Number of batch releases Total time period for a batch release 1.34E+04 Maximum time period for a batch release 3.15E+02 Average time period for a batch release 2.68E+02 Minimum time period for a batch release 1.10E+02 Average total flow during period of release 5.61 E+03 5.3 Abnormal Releases 5.3.1 Gaseous Abnormal Releases There were no Abnormal Gaseous Releases from the site in 2024.

5.3.2 Liquid Abnormal Releases 5.4 There were no Abnormal Liquid Releases from the site in 2024.

Non-routine Planned Discharge Number of releases 9

Total activity released 2.22E-01 Ci 0

minutes minutes minutes minutes 50 minutes minutes minutes minutes gpm

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 18 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station The Grand Gulf Nuclear Station (GGNS) Unit 2 is a partially constructed facility that was abandoned in December 1979. This unit was never completed or operated. Due to ambient environmental conditions and the unfinished status of the Unit 2 turbine building sub-structure high conductivity rainwater is routinely observed to collect in sumps, tunnels and condenser bay. Sample analysis indicates there are fission and activation products in the sump water. Condition Report, CR-GGN-2022-10783, was initiated to discharge the Unit 2 sump water due to the concern if the contaminated water is not removed and the area not remediated appropriately, the potential would exist to release contaminated water to the surrounding environment should the Unit 2 structure degrade, overflow out of the building or become compromised. In 2024 GGNS began collecting water in a 15,000-gallon tank, mixed and sampled in accordance with site procedures, and if within the ODCM limits, discharged through the site approved discharge pathway. The radionuclides detected and average concentrations are listed in Figure 5, Non-Routine Batch Release. The resulting dose to the Total Body was 1.09E-01 mrem and the maximum organ dose was 2.33E-01 mrem. Activity and dose are included in Table 1, Table 8 and Table 9 of this report.

LIQUID RELEASE AND DOSE SU,.V-IARY REPORT

---- (PERMIT BASIS) -----------

Rel ease ID: 4 Non-Routine Batch Release Thru,001

RELEASE DATA=================-=======-==================================

Per iod Star t Date/ Time......................................... 01/01/2024 00:00 Per iod End Date/ Time........................................... 01/01/ 2025 00:00 Total Release Duration (mi nutes )...................................... 1.29E+03 Tot al Undiluted Volume Released (gallons )............................. 1.17E+05 Aver age Undiluted Flowrate (gpm)...................................... 9. 03E+01 Total Dilution Volume (gallons)....................................... 8.02E+06 Aver age Dilution Flowrate (gpm)....................................... 6.22E+03

NUCLIDE DATA============================================================

1-- - -Undiluted----- 1 1-----Diluted------ 1 Average Per cent Average Percent Nuclide uCi uCi/ml of 10*EC uCi/ml of l 0*EC CO-60 1.10E+02 2.49E-07 8.31E-01 3.S7E-09 l. 19E -02 CS-137

6. 60E+01 1.50E-07 1.50E+00 2.14E-09 2.14E-02 Gamma 1.76E+02 3.99E-07 2. 33E+00

5. 71E-*09 3.33E-'92 H-3 2.22E+05 5.03E-04 5.03E+00

7. WE -06 7.20E-02 Beta

2. 22E+05 5.03E-04 5. 03E+00

7. 20E -06

7. 20E-02 Tot al 2.22E+05 5.04E-04 7. 36E+00

7. 21E-06 L 05E-01 Figure 5, Non-Routine Batch Release

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 19 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 5.5 5.6 5.7 5.8 5.9 5.10 Land Use Census Changes The last land use census performed did not identify any new locations that yielded a calculated dose or dose commitment greater than those currently calculated. No milk-producing animals were identified within a five-mile radius of the plant site.

Meteorological Data

1.

Data recovery for reporting period: 99%

2.

Predominant wind direction: From North-Northeast 14.5% of the reporting period

3.

Predominant stability class: D (44.7%)

4.

Average wind speed: 4.1 miles per hour at the 33-foot level

5.

The annual meteorological data (Hourly Average Data or Joint Frequency Distribution) is maintained on site in a file that will be provided to the NRC upon request Effluent Radiation Monitors Out of Service Greater Than 30 Days There were no effluent radiation monitors listed in ODCM Table 6.3.9-1 and 6.3.10-1 that were out of service greater than 30 days in 2024.

Effluent Number of Date Range Out Radiation Days Out of Monitor Name Service of Service N/A N/A N/A Offsite Dose Calculation Manual (ODCM) Changes There were no changes to the ODCM in 2024.

Process Control Program (PCP) Changes There were no changes to the PCP in 2024.

Radioactive Waste Treatment System Changes Reason Out of Service >30 Days N/A There were no changes to the Radioactive Waste Treatment System in 2024.

Additional Notes (ODCM or TS)

NIA 5.11 Other Supplemental Information 5.11.1 Temporary Outside Tanks No temporary outside tanks exceeded ODCM or Technical Specification Limit of 10 curies not including tritium.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 20 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 5.11.2 Independent Spent Fuel Storage Installation (ISFSI) Monitoring Program The ISFSI annual report on radioactive releases is submitted as a separate report.

5.11.3 Sewage Disposal Summary There were no sewage disposals during the reporting period.

5.11.4 Carbon-14 Carbon-14 activity of 1.59E+01 Curies released this year in gaseous form was obtained by estimation using EPRI spreadsheet BWR Source Term Calculation (MAL-1)_r1 and the information in NEAD-NS-11-0060-REV1-EC42519 and adjusted by 315.35 full power production days. Carbon-14 activity reported in the tables of this report are based on a constant release rate. Public dose estimates were performed using methodology from the ODCM which is based on Regulatory Guide 1.109 methodology. C-14 dose is included in dose calculation results in Table 2.

5.11.5 Errata/Corrections to Previous ARERRs There were no errata issued or corrections to previous ARERRs for the 2024 reporting period.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 21 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 6.0 NEI 07-07 ONSITE RADIOLOGICAL GROUNDWATER MONITORING PROGRAM Grand Gulf Nuclear Station has developed a Groundwater Protection Initiative (GPI) program in accordance with NEI 07-07, Industry Ground Water Protection Initiative -

Final Guidance Document [9]. The purpose of the GPI is to ensure timely detection and an effective response to situations involving inadvertent radiological releases to groundwater to prevent migration of licensed radioactive material off-site and to quantify impacts on decommissioning. During 2024, GGNS collected and analyzed groundwater samples in accordance with the requirements of EN-CY-111,

Radiological Groundwater Protection Program.

This section is included in this report to communicate results of NEI 07-07 Radiological Groundwater Monitoring Program. Monitoring wells installed as part of GPI program are sampled and analyzed as summarized in Table 4, Groundwater Protection Program Monitoring Well Sample Schedule. In addition to reporting results from NEI 07-07 monitoring wells, voluntary communications to offsite governmental agencies for onsite leaks or spills per NEI 07-07 Objective 2.2, are also reported as part of this report. It is important to note, samples and results taken in support of NEI 07-07 groundwater monitoring program are not part of the Radiological Environmental Monitoring Program (REMP) but should be reported as part of ARERR.

GPI Ground Water samples were collected from onsite Dewatering Wells (DW),

Monitoring Wells (MW), and Sentinel Wells (SW). Samples were analyzed for Tritium and gamma and selected samples were analyzed for hard-to-detect (HTD) radionuclides (Americium-241, Curium-242, Curium-243/244, lron-55, Nickel-63, Plutonium-238, Strontium-89 and Strontium-90). Analyses are to the Lower Level of Detection (LLD) values for the GGNS Radiological Environmental Monitoring Program.

No dose to the public is attributed to ground water since wells with results above Minimum Detectable Activity (MDA) are bounded by wells which are less than MDA.

Tritium and gamma results are shown in the table below. HTD analyses performed on MW-1148 indicated< MDA for all HTD radionuclides.

Radiological Groundwater Monitoring Program tritium results are summarized in Table 5, Groundwater Protection Program Monitoring Well Tritium Results. No groundwater monitoring locations had detectable gamma or HTD in 2024.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 22 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station Table 4, Groundwater Protection Program Monitoring Well Sample Schedule Installation ID Installation Type Quarterly Annual Rationale Sampling Sampling DW-01 Dewatering Well X

DW-01 plume DW-02 Dewatering Well X

M&E sampling DW-03 Dewatering Well X

M&E sampling DW-04 Dewatering Well X

General detection monitoring DW-05 Dewatering Well X

General detection monitoring DW-07 Dewatering Well X

DW-07 plume MW-01 Monitoring Well X

M&E sampling, DW-01 plume MW-04 Monitoring Well X

General detection monitoring MW-06 Monitoring Well X

DW-07 plume MW-100B Monitoring Well X

General detection monitoring - perimeter well MW-101B Monitoring Well X

DW-01 plume MW-102B Monitoring Well X

General detection monitoring - perimeter well MW-103B Monitoring Well X

General detection monitoring - perimeter well MW-104B Monitoring Well X

General detection monitoring - perimeter well MW-105B Monitoring Well X

DW-01 plume MW-106B Monitoring Well X

DW-01 plume MW-107B Monitoring Well X

DW-07 plume MW-108B Monitoring Well X

DW-07 plume MW-109B Monitoring Well X

DW-07 plume MW-110B Monitoring Well X

DW-07 plume MW-111B Monitoring Well X

DW-01 plume MW-112B Monitoring Well X

M&E sampling, DW-01 plume MW-113B Monitoring Well X

M&E sampling, perimeter well MW-114B Monitoring Well X

DW-01 plume

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 23 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station Table 4, Groundwater Protection Program Monitoring Well Sample Schedule Installation ID Installation Type Quarterly Annual Rationale Sampling Sampling MW-1158 Monitoring Well X

DW-01 plume MW-1168 Monitoring Well X

DW-01 plume MW-1188 Monitoring Well X

DW-01 plume MW-1198 Monitoring Well X

General detection monitoring - perimeter well MW-1208 Monitoring Well X

General detection monitoring - perimeter well MW-1218 Monitoring Well X

General detection monitoring - perimeter well MW-1228 Monitoring Well X

8 quarterly requirement, M&E sampling MW-1238 Monitoring Well X

8 quarterly requirement, M&E sampling MW1007C Monitoring Well X

General detection monitoring MW1009C Monitoring Well X

General detection monitoring MW1012C Monitoring Well X

General detection monitoring MW1020C Monitoring Well X

General detection monitoring MW1024C Monitoring Well X

General detection monitoring MW1027C Monitoring Well X

General detection monitoring MW1042C Monitoring Well X

General detection monitoring MW1082C Monitoring Well X

General detection monitoring MW1134C Monitoring Well X

General detection monitoring P-05 Piezometer X

General detection monitoring SW-103A Monitoring Well X

Discharge pipeline sentinel well SW-101 Sump X

Discharge pipeline sentinel well SW-102 Sump X

Discharge pipeline sentinel well

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 24 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station Table 5, Groundwater Protection Program Monitoring Well Tritium Results Number of Number of Average Maximum Well Name Positive Analyses Concentration1 Concentration Detections (pCi/L)

(pCi/L)

DW-01 2

5 1026 1090 DW-02 2

5 986 1070 DW-03 2

4 855 962 DW-04 4

4 893 1150 DW-05 0

4

<MDA

<MDA DW-07 5

5 1085 1290 MW-01 2

4 636 641 MW-04 0

4

<MDA

<MDA MW-06 7

7 1239 1720 MW-1008 0

1

<MDA

<MDA MW-1018 0

4

<MDA

<MDA MW-1028 0

1

<MDA

<MDA MW-1038 0

1

<MDA

<MDA MW-1048 0

1

<MDA

<MDA MW-1058 2

4 641 653 MW-106B 0

4

<MDA

<MDA MW-107B 0

4

<MDA

<MDA MW-108B 3

4 776 935 MW-109B 5

5 2780 5350 MW-110B 2

5 2925 3160 MW-1118 3

4 2171 3060 MW-1128 1

4 953 953 MW-113B 0

4

<MDA

<MDA MW-1148 4

4 1835 2040 MW-1158 2

4 1580 1660 MW-116B 0

4

<MDA

<MDA MW-1188 2

4 842 845 MW-1198 0

1

<MDA

<MDA MW-120B 0

1

<MDA

<MDA MW-1218 0

1

<MDA

<MDA MW-1228 0

4

<MDA

<MDA MW-1238 0

4

<MDA

<MDA 1 Results <MDA should not be included in the average concentration calculation.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 25 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station Table 5, Groundwater Protection Program Monitoring Well Tritium Results Number of Number of Average Maximum Well Name Positive Analyses Concentration 1 Concentration Detections (pCi/L)

(pCi/L)

MW-1007C 0

1

<MDA

<MDA MW-1009C 0

1

<MDA

<MDA MW-1012C 0

1

<MDA

<MDA MW-1020C 0

2

<MDA

<MDA MW-1024C 0

1

<MDA

<MDA MW-1027B 0

1

<MDA

<MDA MW-1027C 0

1

<MDA

<MDA MW-1042C 0

1

<MDA

<MDA MW-1134B 0

1

<MDA

<MDA MW-1134C 0

1

<MDA

<MDA MW-1082C 0

1

<MDA

<MDA P-05 0

1

<MDA

<MDA SW-103A 0

4

<MDA

<MDA 6.1 Voluntary Notification During 2024, Grand Gulf Nuclear Station did not make a voluntary NEI 07-07 notification to State/Local officials, NRC, and to other stakeholders required by site procedures.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 26 of 33 Company: Entergy Operations, Inc.

I Plant: Grand Gulf Nuclear Station 7.0 BIBLIOGRAPHY

[1] Nuclear Regulatory Commission, 30 June 2015. [Online]. Available: http://www.nrc.gov/reading-rm/basic-ref/students/animated-pwr.html. [Accessed October 2020].

[2] Nuclear Regulatory Commission, 25 June 2015. [Online]. Available: http://www.nrc.gov/reading-rm/basic-ref/students/animated-bwr.html. [Accessed October 2020].

[3] "NCRP Report No. 160 - Ionizing Radiation Exposure of the Population of the United States,"

National Council on Radiation Protection and Measurements, Bethesda, MD, 2009.

[4] Health Physics Society, [Online]. Available: http://hps.org/hpspublications/radiationfactsheets.html.

[Accessed 2020].

[5] "NRC Resource Page," [Online]. Available: http://www.nrc.gov/about-nrc/radiation.html. [Accessed 1 O November 2020].

[6] "Japan Atomic Energy Agency," 06 November 2020. [Online]. Available:

https://www.jaea.go.jp/english/04/ntokai/houkan/houkan_02.html.

[7] "Regulatory Guide 1.109 - Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Demonstrating Compliance with 10 CFR Part 50, Appendix I," Nuclear Regulatory Commission, Ocotober, 1977.

[8] "NUREG-0133 - Preparation of Effluent Technical Specifications for Nuclear Power Plants,"

Nuclear Regulatory Commission, 1987.

[9] "NEI 07 Industry Ground Water Protection Initiative -

Final Guidance Document, Rev. 1,"

Nuclear Energy Institute, Washington, D.C., 2019.

[10] "10 CFR 50 - Domestic Licensing of Production and Utilization Facilities," US Nuclear Regulatory Commission, Washington, DC.

[11] "40 CFR 190 - Environmental Radiation Protection Standards for Nuclear Power Operation," US Environmental Protection Agency, Washington, DC.

[12] "10 CFR 20 - Standards for Protection Against Radiation," US Nuclear Regulatory Commission, Washington, DC.

[13] "40 CFR 141 - National Primary Drinking Water Regulations," US Environmental Protection Agency, Washington, DC..

[14] "NUREG-0324 - XOQDOQ, Program for the Meteorological Evaluation of Routine Effluent Releases at Nuclear Power Stations," Nuclear Regulatory Commission, September, 1977.

[15] "NUREG-1301 - Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Pressurized Water Reactors," Nuclear Regulatory Commission, April 1991.

[16] "NUREG-1302 - Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Boiling Water Reactors," Nuclear Regulatory Commission, April 1991.

[17] "Regulatory Guide 4.13 - Performance, Testing, and Procedural Specifications for Thermoluminescence Dosimetry: Environmental Applications, Revision 2," Nuclear Regulatory Commision, June, 2019.

[18] "Regulatory Guide 4.15 - Quality Assurance for Radiological Monitoring Programs (Inception through Normal Operations to License Termination) -- Effluent Streams and the Environment,"

Nuclear Regulatory Commission, July, 2007.

Annual Radioactive Effluent Release Report I YEAR: 2024 I Page 27 of 33 Company: Enterav Operations, Inc.

I Plant: Grand Gulf Nuclear Station, ARERR Release Summary Tables (RG-1.21 Tables) 1.0 GASEOUS EFFLUENTS Table 6, Gaseous Effluents Summation of All Releases GGNS 1 Quarter Quarter Quarter Quarter Est. Total A. Fission & Activation Gases Unit 1

2 3

4 Annual Error%

1. Total Release Ci 3.57E+01 7.46E+01 8.03E+01 4.31E+01 2.34E+02 6.90E+01