ML21119A124

Annual Radiological Environmental Operating Report

ML21119A124
Person / Time
Site:	Grand Gulf
Issue date:	04/28/2021
From:	Franssen R Entergy Operations
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
GNRO2021/00013
Download: ML21119A124 (47)

Text

Entergy Operations, Inc.

P.O. Box 756 Port Gibson, Mississippi 39150 Robert Franssen Site Vice President Grand Gulf Nuclear Station Tel: 601-437-7500 GNRO2021/00013 April 28, 2021 ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001

SUBJECT:

Grand Gulf Nuclear Station Annual Radiological Environmental Operating Report (AREOR)

Grand Gulf Nuclear Station, Unit 1 NRC Docket No. 50-416 Renewed Facility Operating License No. NPF-29 In accordance with Grand Gulf Nuclear Station Unit 1 Technical Specification 5.6.2, attached is the Annual Radiological Environmental Operating Report (AREOR) for the time-period of January 1, 2020 through December 31, 2020.

This letter contains no new commitments. Should you have any questions concerning this letter or require additional information, please contact Kevin Sanders at 1-601-437-6930.

Sincerely, Robert Franssen RF/rm Attachments: 1. Annual Radiological Environmental Operating Report (AREOR) cc:

NRC Region IV - Regional Administrator NRC Senior Resident Inspector, Grand Gulf Nuclear Station State Health Officer, Mississippi Department of Health NRR Project Manager

GNRO2021/00013 Attachment 1 GNRO2021/00013 Annual Radiological Environmental Operating Report (AREOR)

Page 1 of 46 Plant: Grand Gulf Nuclear Station YEAR: 2020 Document Number: GNRO 2021-00013 Annual Radiological Environmental Operating Report

Plant: Grand Gulf Nuclear Station Year: 2020 Page 2 of 45 Annual Radiological Environmental Operating Report TABLE OF CONTENTS 1.0 EXECUTIVE

SUMMARY

............................................................................................................. 3

2.0 INTRODUCTION

.........................................................................................................................5 3.0 RADIOLOGICAL ENVIRONMENTAL SAMPLING PROGRAM REQUIREMENTS ...................... 6 4.0 INTERPRETATION AND TRENDS OF RESULTS .................................................................... 17 5.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM

SUMMARY

.......................... 22 ATTACHMENTS - Sample Deviations ........................................................................................................ 28 - Monitoring Results Tables ............................................................................................ 29 - Interlaboratory Comparison Program Results ............................................................... 44

Plant: Grand Gulf Nuclear Station Year: 2020 Page 3 of 45 Annual Radiological Environmental Operating Report 1.0 EXECUTIVE

SUMMARY

1.1 Radiological Environmental Monitoring Program The Annual Radiological Environmental Operating Report presents data obtained through analyses of environmental samples collected for Grand Gulf Nuclear Station (GGNS) Radiological Environmental Monitoring Program (REMP) for the period January 1 through December 31, 2020. This report fulfills the requirements of Grand Gulf Nuclear Station Technical Specification 5.6.2.

All required lower limit of detection (LLD) capabilities were achieved in all sample analyses during 2020, as required by the GGNS Offsite Dose Calculation Manual (ODCM) Specifications Table 6.12.1-3. No measurable levels of radiation above baseline levels attributable to GGNS operation were detected in the vicinity of GGNS.

The 2020 Radiological Environmental Monitoring Program thus substantiated the adequacy of source control and effluent monitoring at GGNS with no observed impact of plant operations on the environment.

GGNS established the REMP in 1978 prior to the stations becoming operational (1985) to provide data on background radiation and radioactivity normally present in the area. GGNS has continued to monitor the environment by sampling air, water, sediment, fish, and food products, as well as measuring direct radiation. GGNS also samples milk if milk-producing animals used for human consumption are present within five miles (8 km) of the plant.

The REMP includes sampling indicator and control locations within an approximate 20-mile radius of the plant. The REMP utilizes indicator locations near the site to show any increases or buildup of radioactivity that might occur due to station operation and control locations farther away from the site to indicate the presence of only naturally occurring radioactivity. GGNS personnel compare indicator results with control and preoperational results to assess any impact GGNS operation might have had on the surrounding environment.

In 2020, environmental samples were collected for radiological analysis. The results of indicator locations were compared with control locations and previous studies. It was concluded that no significant relationship exists between GGNS operation and effect on the area around the plant. The review of 2020 data showed radioactivity levels in the environment were undetectable in many locations and near background levels in significant pathways.

1.2 Reporting Levels When averaged over any calendar quarter, no environmental samples equaled or exceeded reporting levels for radioactivity as outlined in ODCM Specifications Table 6.12.1-2; the analytical results did not trigger any Radiological Monitoring Program Special Reports.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 4 of 45 Annual Radiological Environmental Operating Report 1.3 Comparison to State and/or Federal Program GGNS personnel compared REMP data to state monitoring programs as results became available. Historically, the programs used for comparison have included the U.S. Nuclear Regulatory Commission (NRC) Thermoluminescent Dosimeter (TLD)

Direct Radiation Monitoring Network and the Mississippi State Department of Health (MSDH), Division of Radiological Health monitoring program.

The NRC TLD Network Program was discontinued in 1998. Historically these results have compared to those from the GGNS REMP. GGNS TLD results continue to remain similar to the historical average and continue to verify that plant operation is not affecting the ambient radiation levels in the environment.

The MSDH and the GGNS REMP entail similar radiological environmental monitoring program requirements. These programs include collecting air samples and splitting or sharing sample media such as water, sediment, and fish. Both programs have obtained similar results over previous years.

1.4 Sample Deviations During 2020, environmental sampling was performed for 5 media types addressed in the ODCM and for direct radiation. A total of 371 samples of the 375 scheduled were obtained. Of the scheduled samples, 98.9 percent were collected and analyzed in accordance with the requirements specified in the ODCM. Attachment 1 contains the listing of sample deviations and actions taken.

1.5 Program Modifications There were no program modifications during the reporting period.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 5 of 45 Annual Radiological Environmental Operating Report

2.0 INTRODUCTION

2.1 Radiological Environmental Monitoring Program GGNS established the REMP to ensure that plant operating controls properly function to minimize any associated radiation endangerment to human health or the environment. The REMP is designed for:

Analyzing applicable pathways for anticipated types and quantities of radionuclides released into the environment.

• Considering the possibility of a buildup of long-lived radionuclides in the environment and identifying physical and biological accumulations that may contribute to human exposures.

• Considering the potential radiation exposure to plant and animal life in the environment surrounding GGNS.

• Correlating levels of radiation and radioactivity in the environment with radioactive releases from station operation.

2.2 Pathways Monitored The airborne, direct radiation, waterborne and ingestion pathways are monitored as required by GGNS ODCM Table 6.12.1-1. A description of the REMP utilized to monitor the exposure pathways is described in the attached Tables and Figures.

Section 4.0 of this report provides a discussion of 2020 sampling results with Section 5.0 providing a summary of results for the monitored exposure pathways.

2.3 Land Use Census GGNS conducts a land use census biennially, as required by Section 6.12.2 of the ODCM. The purpose of this census is to identify changes in uses of land within five miles of GGNS that would require modifications to the REMP and the ODCM. The most important criteria during this census are to determine the location in each sector of the nearest occupied residence, unoccupied residence, garden, and milking animal.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 6 of 45 Annual Radiological Environmental Operating Report 3.0 RADIOLOGICAL ENVIRONMENTAL SAMPLING PROGRAM REQUIREMENTS Table 1, Exposure Pathway - Airborne Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency RADIOIODINE AND PARTICULATES AS-7 (Sector H, 0.5 miles) -

South-southeast of GGNS at 1 sample close to the SITE BOUNDARY the IBEW Union Hall having the highest calculated annual average ground level D/Q.

RADIOIODINE AND PARTICULATES AS-1 (Sector G, 5.5 miles) -

• Radioiodine Canisters - I-131 analysis every 7 days Southeast of GGNS at the 1 sample from the vicinity of a community Port Gibson City Barn

• Air Particulate - Gross beta radioactivity analysis having the highest calculated annual average 7 days, or more frequently if following filter change ground level D/Q.

required by dust loading.

• Air Particulate - Gamma Isotopic composite (by RADIOIODINE AND PARTICULATES AS-20 (Sector L, 0.9 miles) - location) every 92 days South-southeast of GGNS at 1 sample from the vicinity of a community the former Glodjo residence having the highest calculated annual average ground level D/Q.

RADIOIODINE AND PARTICULATES AS-3 (Sector B, 18 miles) -

North of the Vicksburg Airport 1 sample from a control location 15 - 30 km distance.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 7 of 45 Annual Radiological Environmental Operating Report Table 2, Exposure Pathway - Direct Radiation Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency TLDS

• M-16 (Sector A, Radius 0.9 Miles) - Meteorological Tower.

An inner ring of stations in the general areas 92 days Gamma dose; 92 days of the SITE BOUNDARY.

• M-19 (Sector E, Radius 0.5 Miles) - Eastern SITE BOUNDARY Property line, North-northeast of HWSA.

• M-21 (Sector J, Radius 0.4 Miles) - Near Former Training Center Building on Bald Hill Road.

• M-22 (Sector G, Radius 0.5 Miles) - Former RR Entrance Crossing on Bald Hill Road.

• M-23 (Sector Q, Radius 0.5 Miles) - Gin Lake Road 50 Yards North of Heavy Haul Road on Power Pole.

• M-25 (Sector N, Radius 1.6 Miles) - Radial Well Number 1.

• M-28 (Sector L, Radius 0.9 Miles) - Bald Hill Road.

• M-94 (Sector R, Radius 0.8 Miles) - Sector R Near Meteorological Tower.

• M-95 (Sector F, Radius 0.5 mi) -

Spoils Area, fence of old storage area, near entrance gate

Plant: Grand Gulf Nuclear Station Year: 2020 Page 8 of 45 Annual Radiological Environmental Operating Report Table 2, Exposure Pathway - Direct Radiation Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency TLDS

• M-96 (Sector B, Radius 0.7 mi.) -

North Gate Fence An inner ring of stations in the general areas 92 days Gamma dose; 92 days of the SITE BOUNDARY.

• M-97 (Sector D, Radius 0.8 mi.) -

Grand Gulf Road entrance gate to spoils area

• M-98 (Sector H, Radius 0.5 mi.) -

Bald Hill Road, across from Union Hall, in curve

• M-99 (Sector K, Radius 0.4 mi.) -

North Fence of old Ball Field near utility pole

• M-100 (Sector C, Radius 0.6 mi.)

- Grand Gulf Road

Plant: Grand Gulf Nuclear Station Year: 2020 Page 9 of 45 Annual Radiological Environmental Operating Report Table 2, Exposure Pathway - Direct Radiation Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency TLDS

• M-36 (Sector P, Radius 5.0 Miles) - Curve on HW 608, Point An outer ring of stations approximately 3 to 5 92 days Gamma dose; 92 days Nearest GGNS at Power Pole.

miles from the site.

• M-40 (Sector M, Radius 2.3 Miles) - Headly Drive, Near River Port Entrance.

• M-48 (Sector K, Radius 4.8 Miles) - 0.4 Miles South on Mont Gomer Road on West Side.

• M-49 (Sector H, Radius 4.5 Miles) - Fork in Bessie Weathers Road/Shaifer Road.

• M-50 (Sector B, Radius 5.3 Miles) - Panola Hunting Club Entrance.

• M-55 (Sector D, Radius 5.0 Miles) - Near Ingelside Karnac Ferry Road/Ashland Road Intersection.

• M-57 (Sector F, Radius 4.5 Miles) - Hwy 61, Behind the Welcome to Port Gibson Sign at Glensdale Subdivision.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 10 of 45 Annual Radiological Environmental Operating Report Table 2, Exposure Pathway - Direct Radiation Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency TLDS

• M-01 (Sector E, Radius 3.5 Miles) - Across the road from Additional stations in special interest areas 92 days Gamma dose; 92 days Lake Claiborne Entry Gate.

such as population centers, nearby (Special) residences, schools, and in 1 or 2 areas to serve as control locations.

• M-07 (Sector G, Radius 5.5 Miles) - AS-1 PG, Port Gibson City Barn. (Special)

• M-09 (Sector D, Radius 3.5 Miles) - Warner Tully Y-Camp.

(Special)

• M-10 (Sector A, Radius 1.5 Miles) - Grand Gulf Military Park.

(Special)

• M-14 (Sector B, Radius 18.0 Miles) - AS-3-61VA, Hwy 61, North of Vicksburg Airport.

(Control)

• M-33 (Sector P, Radius 12.5 Miles) - Newellton, Louisiana Water Tower. (Control)

• M-38 (Sector M, Radius 9.5 Miles) - Lake Bruin State Park, Entrance Road. (Special)

• M-39 (Sector M, Radius 13.0 Miles) - St. Joseph, Louisiana, Auxiliary Water Tank. (Special)

Plant: Grand Gulf Nuclear Station Year: 2020 Page 11 of 45 Annual Radiological Environmental Operating Report Table 3, Exposure Pathway - Waterborne Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency

• MRUP (Sector R, Radius 1.8 Miles) - At least 4500 ft upstream 92 days Gamma isotopic and tritium analysis; 92 days of the GGNS discharge point into SURFACE WATER the Mississippi River to allow adequate mixing of the Mississippi 1 sample upstream and 1 sample and Big Black Rivers.

downstream.

• MRDOWN (Sector N, Radius 1.6 Miles) - At least 5000 ft downstream of the GGNS discharge point in the Mississippi River near Radial Well No. 1.

• MRDOWN (Sector P, Radius 1.3 Miles) - Downstream of the 1 sample downstream during a Liquid GGNS discharge point in the 366 days Gamma isotopic and tritium analysis; 366 days Radwaste Discharge.

Mississippi River near Radial Well No. 5.

• OUTFALL 007 (Sector N, Radius 1 sample from Outfall 007 31 days Tritium; 31 days 0.2 Miles) - Storm Drain System

• PGWELL (Sector G, Radius 5.0 Miles) - Port Gibson Wells -

366 days Gamma isotopic and tritium analysis; 366 days Taken from distribution system or GROUNDWATER one of the five wells.

Samples from 2 sources

• CONSTWELL (Sector Q, Radius 0.4 Miles) - GGNS Construction Water Well - Taken from distribution system or the well.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 12 of 45 Annual Radiological Environmental Operating Report Table 3, Exposure Pathway - Waterborne Sample Point Description Sampling and Collection Requirement Type and Frequency of Analyses Distance and Direction Frequency SEDIMENT FROM SHORELINE

• SEDHAM (Sector N, Radius 1.6 Miles) - Downstream of the 1 sample from downstream area and 1 366 days Gamma isotopic; 366 days GGNS discharge point in the sample from upstream area Mississippi River near Hamilton Lake outlet.

• SEDCONT (Minimum of 100 yds)

- Upstream of the GGNS discharge point in the Mississippi River.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 13 of 45 Annual Radiological Environmental Operating Report Table 4, Exposure Pathway - Ingestion Sample Point Description Distance Sampling and Collection Requirement Type and Frequency of Analyses and Direction Frequency MILK

• If commercially available, 1 sample from

• Currently, no available milking animals 92 days when required Gamma isotopic and I-131; 92 days milking animals within 8 km distant within 8 km of GGNS.

• 1 sample from milking animals at a

• ALCONT (Sector K, Radius 10.5 control location >8 km distant when an Miles) - Located South-southwest of indicator location exists. GGNS at Alcorn State University.

(Control)

FISH AND INVERTEBRATES

• FISHDOWN - Downstream of the GGNS discharge point into the

• 1 sample in vicinity of GGNS discharge 366 days Gamma isotopic on edible portions; 366 days Mississippi River point.

• FISHUP - Upstream of the GGNS

• 1 sample uninfluenced by GGNS discharge point into the Mississippi discharge.

River uninfluenced by plant operations.

FOOD PRODUCTS

• VEG-J (Sector J, Radius 0.4 Miles) -

South of GGNS near former Training

• 1 sample of broadleaf vegetation grown in 92 days when available Gamma isotopic and I-131; 92 days Center on Bald Hill Road.

one of two different offsite locations with highest anticipated annual average

• VEG-CONT (Sector K, Radius 10.5 ground level D/Q if milk sampling is not Miles) - Alcorn State University south-performed. southwest of GGNS when available, otherwise a location 15-30 km distant.

• 1 sample of similar vegetation grown 15 - (Control) 30 km distant if milk sampling is not performed.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 14 of 45 Annual Radiological Environmental Operating Report Figure 1, Exposure Pathway

Plant: Grand Gulf Nuclear Station Year: 2020 Page 15 of 45 Annual Radiological Environmental Operating Report Figure 2, Sample Collection Sites -Near Field

Plant: Grand Gulf Nuclear Station Year: 2020 Page 16 of 45 Annual Radiological Environmental Operating Report Figure 3, Sample Collection Sites - Far Field

Plant: Grand Gulf Nuclear Station Year: 2020 Page 17 of 45 Annual Radiological Environmental Operating Report 4.0 INTERPRETATION AND TRENDS OF RESULTS 4.1 Air Particulate and Radioiodine Sample Results GGNS did not detect any plant related gamma emitting radionuclides in the quarterly air particulate composites. The REMP had previously detected airborne radioactivity attributable to other sources in this pathway. These sources include the Chinese nuclear test in 1980 and the accident at the Chernobyl Nuclear Power Plant in 1986.

The GGNS REMP detected radioactivity released from the Fukushima Dai-ichi Nuclear Power Plant following the March 11, 2011, Tohoku earthquake.

In 2020 there were no samples above the LLD for I-131. Indicator gross beta air particulate results for 2020 were comparable to results obtained from 2010-2019 of the operational REMP. Also, the 2020 gross beta annual average was less than the average for preoperational levels. Results are reported as annual average picocuries per cubic meter (pCi/m3).

Monitoring Period Result 2010 - 2019 (Minimum Value) 0.009 2020 Average Value 0.018 2010 - 2019 (Maximum Value) 0.043 Preoperational 0.032 In the absence of plant-related gamma radionuclides, gross beta activity is attributed to naturally occurring radionuclides. Table 3.1, which include gross beta concentrations and provide a comparison of the indicator and control means and ranges emphasizes the consistent trends seen in this pathway to support the presence of naturally occurring activity. Therefore, it can be concluded that the airborne pathway continues to be unaffected by Grand Gulf Nuclear Station operations.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 18 of 45 Annual Radiological Environmental Operating Report 4.2 Thermoluminescent Dosimetry (TLD) Sample Results Grand Gulf Nuclear Station reports measured dose as net exposure (field reading less transit reading) normalized to 92 days and relies on comparison of the indicator locations to the control as a measure of plant impact. Grand Gulf Nuclear Stations comparison of the inner ring and special interest area TLD results to the control, as seen in Table 7, identified no noticeable trend that would indicate that the ambient radiation levels are being affected by plant operations. In addition, the inner ring value of 9.6 millirem/quarter (mR/Qtr) shown in Table 7 for 2020 is within the historical bounds of 2010 - 2019 annual average results, which have ranged from 9.3 to 10.8 mrem. Overall, Grand Gulf Nuclear Station concluded that the ambient radiation levels are not being affected by plant operations.

Table 5, Direct Radiation Annual Summary Year Inner Ring (mR/Qtr) Outer Ring (mR/Qtr) Control Location (mR/Qtr) 2010 10.8 10.5 12.1 2011 10.0 10.2 11.4 2012 9.5 9.7 11.0 2013 9.8 9.7 10.8 2014 10.0 9.9 11.0 2015 9.6 9.5 10.8 2016 9.3 9.3 10.7 2017 9.9 9.9 11.3 2018 9.7 9.8 10.6 2019 10.0 9.7 10.7 2020 9.6 9.4 10.7 4.3 Waterborne Sample Results Analytical results for 2020 surface water and drinking water samples were similar to those reported in previous years. Gamma radionuclides analytical results for 2020 surface water samples were similar to those reported in previous years. Tritium in Grand Gulf Nuclear Station surface water indicator samples continues to be detected, but is attributed to washout and entrainment of normal, previously monitored gaseous effluents. These results are further explained below.

4.3.1 Surface Water Samples were collected from two indicator locations (Outfall 007, MRDOWN) and one control location (MRUP) and analyzed for gamma emitting radionuclides and tritium. Plant related gamma emitting radionuclides and tritium remained undetectable in the upstream and downstream Mississippi River locations, which is consistent with previous operational years.

Storm waters contribute to Outfall 007 and can include tritium as a result of washout and

Plant: Grand Gulf Nuclear Station Year: 2020 Page 19 of 45 Annual Radiological Environmental Operating Report entrainment of normal, previously monitored gaseous effluents. As a result, tritium is occasionally observed. Tritium was measured during February (1480 pCi/L) at the Outfall 007 location. Tritium was also measured in the duplicate samples collected during February (1640 pCi/L). Tritium was not observed in the remaining Outfall 007 samples collected during 2020.

Results are reported as annual average pCi/l.

Monitoring Period Result 2010 - 2019 (Minimum Value) 795 2020 (Value) 1560 2010 - 2019 (Maximum Value) 8863 Preoperational 2739 In addition to the tritium samples required by the REMP, six special surface water samples for gamma emitting radionuclides were collected at the Outfall 007 location.

Plant related gamma emitting radionuclides remained undetectable in these samples.

Grand Gulf Nuclear Station personnel have noted no definable increasing trends associated with the tritium levels at the discharge location. Levels detected during 2020 and previous operational years have been well below regulatory reporting limits.

Therefore, the operation of Grand Gulf Nuclear Station had no definable impact on this waterborne pathway during 2020 and levels of radionuclides remain similar to those obtained in previous operational years.

4.3.2 Drinking Water Drinking water samples were collected from two locations, CONSTWELL (indicator) and PGWELL (control). Drinking water samples were analyzed for I-131, gamma radionuclides and tritium. During 2020, gamma radionuclides, I-131, and tritium concentrations were below the LLD limits at the indicator and control locations, which is consistent with previous operational years. Results are reported as annual average pCi/L.

Radionuclide 2020 2010 - 2019 Preoperational Gross Beta < LLD < LLD < LLD Iodine-131 < LLD < LLD < LLD Gamma < LLD < LLD < LLD Tritium < LLD < LLD <LLD Grand Gulf Nuclear Station personnel have noted no definable trends associated with drinking water results at the indicator location. Therefore, the operation of Grand Gulf Nuclear Station had no definable impact on this waterborne pathway during 2020 and levels of radionuclides remain similar to those obtained in previous operational years.

Results from 2020 are summarized in Table 7.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 20 of 45 Annual Radiological Environmental Operating Report 4.3.3 Groundwater Groundwater monitoring data collected during administration of the Groundwater Protection Initiative (GPI) site program are included in the Annual Radioactive Effluent Release Report.

4.4 Soil Sample Results Sediment samples were collected from two locations in 2020 and analyzed for gamma radionuclides. Listed below is a comparison of 2020 indicator results to the 2010 - 2019 operational years. Grand Gulf Nuclear Station operations had no significant impact on the environment or public by this waterborne pathway. Results are reported as pCi/kg.

Monitoring Period Result 2010 - 2019 (Minimum Value) <LLD 2020 Value < LLD 2010 - 2019 (Maximum Value) 40.3 Preoperational 295.0 4.5 Ingestion Sample Results 4.5.1 Milk Sample Results Milk samples were not collected during 2020 due to the unavailability of indicator locations within five miles of Grand Gulf Nuclear Station.

4.5.2 Fish Sample Results Fish samples were collected from two locations and analyzed for gamma radionuclides. In 2020, gamma radionuclides were below detectable limits which are consistent with preoperational and operational years. Therefore, based on these measurements, Grand Gulf Nuclear Station operations had no significant radiological impact upon the environment or public by this ingestion pathway.

4.5.3 Food Product Sample Results The REMP has detected radionuclides prior to 1990 that are attributable to other sources. These include the radioactive plume release due to reactor core degradation at Chernobyl Nuclear Power Plant in 1986 and atmospheric weapons testing.

In 2020, food product samples were collected from two locations and analyzed for plant related Iodine-131 and gamma radionuclides. The 2020 levels remained undetectable, as has been the case in previous years. Therefore, based on these measurements, Grand Gulf Nuclear Station operations had no significant radiological impact upon the environment or public by this ingestion pathway.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 21 of 45 Annual Radiological Environmental Operating Report 4.6 Land Use Census Results The latest land use census, performed in 2020, did not identify any new locations that yielded a calculated dose or dose commitment greater than those currently calculated.

The land use census identified no milk-producing animals within a five-mile radius of the plant site. In accordance with ODCM Section 6.12.1, Grand Gulf Nuclear Station personnel sampled broadleaf vegetation.

Table 6, Land Use Census - 2020 Nearest Residence Within Five Miles Sector Direction Nearest Residence (miles) Nearest Garden (miles)

A N 1.02 1.02 B NNE 1.51 1.52 C NE 0.70 4.14 D ENE 2.60 4.50 E E 0.83 0.91 F ESE 2.25 4.51 G SE 3.72 4.20 H SSE 1.10 4.31 J S 3.14 3.16 K SSW 2.20 2.18 L SW 0.89 0.89 M WSW none within 5 miles none within 5 miles N W none within 5 miles none within 5 miles P WNW none within 5 miles none within 5 miles Q NW none within 5 miles none within 5 miles R NNW 1.44 none within 5 miles The next land use census is scheduled to be conducted in 2022.

4.7 Interlaboratory Comparison Results Attachment 3 contains result summary for Interlaboratory Comparison program for Teledyne Brown Engineering.

5.0 RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM

SUMMARY

1. Table 7, Radiological Environmental Monitoring Program Summary, summarizes data for the 2020 REMP program.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 22 of 45 Annual Radiological Environmental Operating Report Table 7, Radiological Environmental Monitoring Program Summary Location with the Highest Annual Control Type / Number Indicator Locations Mean Number of Sample Type [Note 2] Locations of Analyses LLD Mean (F)[Note 3] Non-Routine (Units) Mean (F)[Note 3]

[Note 1]

[Range] Mean (F)[Note 3] Results [Note 5]

Location [Note 4] [Range]

[Range]

GB / 208 0.01 0.0177 (156 / 156) AS-1 PG 0.0182 (52 / 52) 0.0185 (52 / 52) 0 Air [0.0060 - 0.0340] (Sector G, 5.5 mi) [0.0071 - 0.0340] [0.0084 - 0.0338]

Particulates GS / 16 (pCi/m3) Cs-134 0.05 <LLD N/A N/A <LLD 0 CS-137 0.06 <LLD N/A N/A <LLD 0 Airborne I-131 / 208 0.07 < LLD N/A N/A < LLD 0 Iodine (pCi/ m3)

Inner Ring Gamma / 52 [Note 6]

9.57 (52 / 52) M-99 11.9 (4 / 4) N/A 0 TLDs (mR/Qtr)

[5.3 - 14.6] (Sector J, 0.4 mi.) [10.2 - 14.6]

Outer Ring Gamma / 28 [Note 6] 9.4 (28 / 28) M-57 11.3 (4 / 4) 0 N/A TLDs (mR/Qtr) [3.6 - 12.2] (Sector F, 4.5 mi.) [9.4 - 12.2]

Special Interest TLDs Gamma / 28 [Note 6] 9.2 (28 / 28) M-01 11.3 (4 / 4) N/A 0 (mR/Qtr) [6.3 - 12.5] (Sector E, 3.5 mi.) [10.0 - 12.5]

Control TLD N/A 10.7 (4 / 4) 0 Gamma / 4 [Note 6] N/A N/A (mR/Qtr) [9.3 - 11.4]

Plant: Grand Gulf Nuclear Station Year: 2020 Page 23 of 45 Annual Radiological Environmental Operating Report Table 7, Radiological Environmental Monitoring Program Summary Location with the Highest Annual Control Type / Number Indicator Locations Mean Number of Sample Type Locations of Analyses LLD [Note 2]

Mean (F)[Note 3] Non-Routine (Units) Mean (F)[Note 3]

[Note 1]

[Range] Mean (F)[Note 3] Results [Note 5]

Location [Note 4] [Range]

[Range]

H-3 / 37 3000 1560 (2 / 30) Outfall 007 1560 (2 / 21) < LLD 0

[1480 - 1640] (Sector N, 0.2 mi.) [1480 - 1640]

GS / 16 Mn-54 15 < LLD N/A N/A < LLD 0 Fe-59 30 < LLD N/A N/A < LLD 0 Co-58 15 < LLD N/A N/A < LLD 0 Co-60 15 < LLD N/A N/A < LLD 0 Surface Water Zn-65 30 < LLD N/A N/A < LLD 0 (pCi/l)

Zr-95 30 < LLD N/A N/A < LLD 0 Nb-95 15 < LLD N/A N/A < LLD 0 I-131 15 < LLD N/A N/A < LLD 0 Cs-134 15 < LLD N/A N/A < LLD 0 Cs-137 18 < LLD N/A N/A < LLD 0 Ba-140 60 < LLD N/A N/A < LLD 0 La-140 15 < LLD N/A N/A < LLD 0

Plant: Grand Gulf Nuclear Station Year: 2020 Page 24 of 45 Annual Radiological Environmental Operating Report Table 7, Radiological Environmental Monitoring Program Summary Location with the Highest Annual Control Type / Number Indicator Locations Mean Number of Sample Type Locations of Analyses LLD [Note 2]

Mean (F)[Note 3] Non-Routine (Units) Mean (F)[Note 3]

[Note 1]

[Range] Mean (F)[Note 3] Results [Note 5]

Location [Note 4] [Range]

[Range]

I-131 / 4 1 < LLD N/A N/A < LLD 0 H-3 / 4 2000 < LLD N/A N/A < LLD 0 GS / 4 Mn-54 15 < LLD N/A N/A < LLD 0 Fe-59 30 < LLD N/A N/A < LLD 0 Drinking Water Co-58 15 < LLD N/A N/A < LLD 0 (pCi/1) Co-60 15 < LLD N/A N/A < LLD 0 Zn-65 30 < LLD N/A N/A < LLD 0 Zr-95 30 < LLD N/A N/A < LLD 0 Nb-95 15 < LLD N/A N/A < LLD 0 Cs-134 15 < LLD N/A N/A < LLD 0 Cs-137 18 < LLD N/A N/A < LLD 0 Ba-140 60 < LLD N/A N/A < LLD 0 La-140 15 < LLD N/A N/A < LLD 0 GS / 4 Sediment Cs-134 150 < LLD N/A N/A N/A 0 (pCi/kg) Cs-137 180 < LLD N/A N/A N/A 0

Plant: Grand Gulf Nuclear Station Year: 2020 Page 25 of 45 Annual Radiological Environmental Operating Report Table 7, Radiological Environmental Monitoring Program Summary Location with the Highest Annual Control Type / Number Indicator Locations Mean Number of Sample Type Locations of Analyses LLD [Note 2]

Mean (F)[Note 3] Non-Routine (Units) Mean (F)[Note 3]

[Note 1]

[Range] Mean (F)[Note 3] Results [Note 5]

Location [Note 4] [Range]

[Range]

GS / 2 Mn-54 130 < LLD N/A N/A < LLD 0 Fe-59 260 < LLD N/A N/A < LLD 0 Co-58 130 < LLD N/A N/A < LLD 0 Fish (pCi/kg)

Co-60 130 < LLD N/A N/A < LLD 0 Zn-65 260 < LLD N/A N/A < LLD 0 Cs-134 130 < LLD N/A N/A < LLD 0 Cs-137 150 < LLD N/A N/A < LLD 0 I-131 / 10 60 < LLD N/A N/A N/A 0 Food Products GS / 10 (pCi/kg)

Cs-134 60 < LLD N/A N/A N/A 0 Cs-137 80 < LLD N/A N/A N/A 0

Plant: Grand Gulf Nuclear Station Year: 2020 Page 26 of 45 Annual Radiological Environmental Operating Report Table 7, Radiological Environmental Monitoring Program Summary Location with the Highest Annual Control Type / Number Indicator Locations Mean Number of Sample Type Locations of Analyses LLD [Note 2]

Mean (F)[Note 3] Non-Routine (Units) Mean (F)[Note 3]

[Note 1]

[Range] Mean (F)[Note 3] Results [Note 5]

Location [Note 4] [Range]

[Range]

GS / 6 Mn-54 15 < LLD N/A N/A < LLD 0 Fe-59 30 < LLD N/A N/A < LLD 0 Co-58 15 < LLD N/A N/A < LLD 0 Co-60 15 < LLD N/A N/A < LLD 0 Surface Water Zn-65 30 < LLD N/A N/A < LLD 0 (Special) Zr-95 30 < LLD N/A N/A < LLD 0 (pCi/l) Nb-95 15 < LLD N/A N/A < LLD 0 Cs-134 15 < LLD N/A N/A < LLD 0 Cs-137 18 < LLD N/A N/A < LLD 0 Ba-140 60 < LLD N/A N/A < LLD 0 La-140 15 < LLD N/A N/A < LLD 0

Plant: Grand Gulf Nuclear Station Year: 2020 Page 27 of 45 Annual Radiological Environmental Operating Report Table 7, Radiological Environmental Monitoring Program Summary Location with the Highest Annual Control Type / Number Indicator Locations Mean Number of Sample Type Locations of Analyses LLD [Note 2]

Mean (F)[Note 3] Non-Routine (Units) Mean (F)[Note 3]

[Note 1]

[Range] Mean (F)[Note 3] Results [Note 5]

Location [Note 4] [Range]

[Range]

GS / 1 Mn-54 130 < LLD N/A N/A < LLD 0 Fe-59 260 < LLD N/A N/A < LLD 0 Meat Co-58 130 < LLD N/A N/A < LLD 0 (Special)

Co-60 130 < LLD N/A N/A < LLD 0 (pCi/kg)

Zn-65 260 < LLD N/A N/A < LLD 0 Cs-134 130 < LLD N/A N/A < LLD 0 Cs-137 150 < LLD N/A N/A < LLD 0 LEGEND:

[Note 1] - GB = Gross beta; I-131 = Iodine-131; H-3 = Tritium; GS = Gamma scan.

[Note 2] - LLD = Required lower limit of detection based on ODCM Table 6.12.1-3.

[Note 3] - Mean and range based upon detectable measurements only. Fraction of detectable measurements at specified locations is indicated in parenthesis (F).

[Note 4] - Where applicable, locations are specified (1) by name, (2) distance from reactor site, and (3) meteorological sector.

[Note 5] - Non-routine results are those which exceed ten times the control station value. If no control station value is available, the result is considered non-routine if it exceeds ten times the preoperational value for the location.

[Note 6] - LLD is not defined in ODCM Table 6.12.1-3.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 28 of 45 Annual Radiological Environmental Operating Report Attachment 1 Page 1 of 1 Sample Deviations Table 8, Sample Deviations Table Sample Comment Sample Media Date Problem Evaluation / Actions No. Location Affected During collection of first quarter 2020 TLDs, two locations, M-23 and M-25, M-23, were inaccessible due to high Mississippi River water level. New TLDs 1 TLD 04/08/20 Inaccessible M-25 were installed when the locations became accessible in July 2020. CR-GGN-2020-04888 documents the condition.

During collection of second quarter 2020 TLDs, two locations, M-23 and M-25, were unavailable for collection. Due to high Mississippi River water M-23, 2 TLD 07/07/20 Unavailable level in April 2020, second quarter TLDs were not installed at these M-25 locations. New TLDs were installed when the locations became accessible in July 2020. CR-GGN-2020-07873 documents the condition.

During collection of third quarter 2020 TLDs, one location, M-100, was found on the ground. The TLD was knocked to the ground by a fallen tree.

3 TLD M-100 10/06/20 Displaced The TLD was collected and analyzed. A new TLD was installed. CR-GGN-2020-10407 documents the condition.

During collection of fourth quarter 2020 TLDs, one location, M-60, was 4 TLD M-60 01/05/21 Wet found wet The TLD was collected and analyzed. A new TLD was installed.

CR-GGN-2021-00046 documents the condition.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 29 of 45 Annual Radiological Environmental Operating Report Page 1 of 16 Monitoring Results Tables Table 9, Air Particulate Data Summary Table Analysis: Gross Beta Units: pCi/m3 Station Station Station Station Start Date End Date AS-1 AS-7 AS-20 AS-3 [Note 1]

(Indicator) (Indicator) (Indicator) (Control)

REQUIRED LLD 0.01 0.01 0.01 0.01 12/31/19 01/07/20 0.01230 0.01290 0.01620 0.01290 01/07/20 01/14/20 0.01050 0.01230 0.00944 0.01250 01/14/20 01/21/20 0.01220 0.01360 0.01560 0.01720 01/21/20 01/28/20 0.01840 0.02050 0.01570 0.01740 01/28/20 02/04/20 0.01940 0.01800 0.02260 0.01990 02/04/20 02/11/20 0.01250 0.01460 0.01110 0.01380 02/11/20 02/18/20 0.00714 0.00770 0.00867 0.00842 02/18/20 02/25/20 0.01600 0.01360 0.01630 0.01940 02/25/20 03/03/20 0.01970 0.01600 0.01750 0.01460 03/03/20 03/10/20 0.01410 0.01630 0.01140 0.01450 03/10/20 03/17/20 0.01220 0.01350 0.01170 0.01460 03/17/20 03/24/20 0.01390 0.01350 0.01230 0.01130 03/24/20 03/31/20 0.01560 0.01520 0.01300 0.01270 03/31/20 04/07/20 0.02440 0.02180 0.01940 0.02110 04/07/20 04/14/20 0.01680 0.01290 0.01890 0.01630 04/14/20 04/21/20 0.01780 0.01350 0.01880 0.01530 04/21/20 04/28/20 0.01190 0.01180 0.01380 0.01760 04/28/20 05/05/20 0.01760 0.01760 0.01490 0.02010 05/05/20 05/12/20 0.01560 0.01080 0.01140 0.01180 05/12/20 05/19/20 0.01220 0.01210 0.01650 0.02220 05/19/20 05/26/20 0.01880 0.01510 0.01610 0.01510 05/26/20 06/02/20 0.01710 0.01410 0.01640 0.01720 06/02/20 06/09/20 0.01530 0.01310 0.01460 0.01540 06/09/20 06/16/20 0.01910 0.02010 0.01940 0.02190 06/16/20 06/23/20 0.02390 0.02390 0.02170 0.02240 06/23/20 06/30/20 0.01480 0.01440 0.01680 0.01470 06/30/20 07/07/20 0.01680 0.01880 0.01730 0.01910

Plant: Grand Gulf Nuclear Station Year: 2020 Page 30 of 45 Annual Radiological Environmental Operating Report Attachment 2 Page 2 of 15 Monitoring Results Tables Table 9, Air Particulate Data Summary Table Analysis: Gross Beta Units: pCi/m3 Station Station Station Station Start Date End Date AS-1 AS-7 AS-20 AS-3 [Note 1]

(Indicator) (Indicator) (Indicator) (Control)

REQUIRED LLD 0.01 0.01 0.01 0.01 07/07/20 07/14/20 0.01620 0.01710 0.01400 0.01770 07/14/20 07/21/20 0.01840 0.02300 0.01670 0.02250 07/21/20 07/28/20 0.00758 0.00769 0.00604 0.00896 07/28/20 08/04/20 0.01720 0.01950 0.01790 0.01970 08/04/20 08/11/20 0.03280 0.03010 0.03000 0.03240 08/11/20 08/18/20 0.01730 0.01680 0.01890 0.01590 08/18/20 08/25/20 0.02340 0.02470 0.02520 0.02680 08/25/20 09/01/20 0.01110 0.00922 0.01130 0.00983 09/01/20 09/08/20 0.02270 0.02620 0.02350 0.02850 09/08/20 09/15/20 0.01700 0.01140 0.01420 0.01380 09/15/20 09/22/20 0.03400 0.02950 0.02610 0.03150 09/22/20 09/29/20 0.01300 0.01480 0.01230 0.01610 09/29/20 10/06/20 0.02630 0.02550 0.02450 0.02280 10/06/20 10/13/20 0.02040 0.02100 0.01780 0.02090 10/13/20 10/20/20 0.02350 0.02060 0.02220 0.01940 10/20/20 10/27/20 0.01860 0.01590 0.01600 0.01670 10/27/20 11/03/20 0.03280 0.02800 0.03090 0.03380 11/03/20 11/10/20 0.02100 0.02200 0.02000 0.01900 11/10/20 11/17/20 0.02140 0.01790 0.01770 0.01870 11/17/20 11/24/20 0.02040 0.01510 0.01760 0.01570 11/24/20 12/01/20 0.02330 0.02540 0.02340 0.02060 12/01/20 12/08/20 0.01700 0.01670 0.01750 0.01750 12/08/20 12/15/20 0.02320 0.02720 0.02630 0.02870 12/15/20 12/22/20 0.02170 0.02190 0.02270 0.02370 12/22/20 12/29/20 0.01980 0.01620 0.01810 0.02050

[Note 1] - Station with highest annual mean.

Plant: Grand Gulf Nuclear Station Year: 2020 Page 31 of 45 Annual Radiological Environmental Operating Report Page 3 of 15 Monitoring Results Tables Table 10, Radioiodine Cartridge Data Table Summary Analysis: I-131 Units: pCi/m3 AS-1 AS-7 AS-20 AS-3 Start Date End Date (Indicator) (Indicator) (Indicator) (Control)

REQUIRED LLD 0.07 0.07 0.07 0.07 12/31/19 01/07/20 <0.03956 <0.03864 <0.04058 <0.04008 01/07/20 01/14/20 <0.03111 <0.03104 <0.03127 <0.03095 01/14/20 01/21/20 <0.02404 <0.02362 <0.02316 <0.02422 01/21/20 01/28/20 <0.02812 <0.02769 <0.02789 <0.02803 01/28/20 02/04/20 <0.02914 <0.02845 <0.02895 <0.02892 02/04/20 02/11/20 <0.06609 <0.06655 <0.06696 <0.06611 02/11/20 02/18/20 <0.02780 <0.02762 <0.02765 <0.02803 02/18/20 02/25/20 <0.02898 <0.02919 <0.02916 <0.02909 02/25/20 03/03/20 <0.02175 <0.02152 <0.02183 <0.02147 03/03/20 03/10/20 <0.02622 <0.02697 <0.02706 <0.02708 03/10/20 03/17/20 <0.03238 <0.03243 <0.03293 <0.03256 03/17/20 03/24/20 <0.02138 <0.02134 <0.02183 <0.02127 03/24/20 03/31/20 <0.03323 <0.03332 <0.01379 <0.03308 03/31/20 04/07/20 <0.06084 <0.06323 <0.06083 <0.06056 04/07/20 04/14/20 <0.02973 <0.02951 <0.03051 <0.02933 04/14/20 04/21/20 <0.03027 <0.02981 <0.02993 <0.02976 04/21/20 04/28/20 <0.03288 <0.03556 <0.03245 <0.0326 04/28/20 05/05/20 <0.02591 <0.02553 <0.02535 <0.02545 05/05/20 05/12/20 <0.02887 <0.02848 <0.02850 <0.02840 05/12/20 05/19/20 <0.02483 <0.02433 <0.02445 <0.02437 05/19/20 05/26/20 <0.04481 <0.04419 <0.04445 <0.04398 05/26/20 06/02/20 <0.03742 <0.03655 <0.01531 <0.03733 06/02/20 06/09/20 <0.03529 <0.03487 <0.03477 <0.03484 06/09/20 06/16/20 <0.05028 <0.04922 <0.04867 <0.04970 06/16/20 06/23/20 <0.03504 <0.03464 <0.03440 <0.03484 06/23/20 06/30/20 <0.01710 <0.01707 <0.01716 <0.01733 06/30/20 07/07/20 <0.02212 <0.02243 <0.02203 <0.02214

Plant: Grand Gulf Nuclear Station Year: 2020 Page 32 of 45 Annual Radiological Environmental Operating Report Page 4 of 15 Monitoring Results Tables Table 10, Radioiodine Cartridge Data Table Summary Analysis: I-131 Units: pCi/m3 AS-1 AS-7 AS-20 AS-3 Start Date End Date (Indicator) (Indicator) (Indicator) (Control)

REQUIRED LLD 0.07 0.07 0.07 0.07 07/07/20 07/14/20 <0.04587 <0.04501 <0.04540 <0.04563 07/14/20 07/21/20 <0.03037 <0.03006 <0.03048 <0.03049 07/21/20 07/28/20 <0.03601 <0.03439 <0.03550 <0.03631 07/28/20 08/04/20 <0.02991 <0.02937 <0.02930 <0.03008 08/04/20 08/11/20 <0.02795 <0.02794 <0.02766 <0.02778 08/11/20 08/18/20 <0.04350 <0.01784 <0.04273 <0.04343 08/18/20 08/25/20 <0.02914 <0.02874 <0.02861 <0.03088 08/25/20 09/01/20 <0.03568 <0.03477 <0.03408 <0.03346 09/01/20 09/08/20 <0.06094 <0.05954 <0.05926 <0.05921 09/08/20 09/15/20 <0.04277 <0.04297 <0.04299 <0.04330 09/15/20 09/22/20 <0.04861 <0.04871 <0.04884 <0.05028 09/22/20 09/29/20 <0.03268 <0.03187 <0.03270 <0.03370 09/29/20 10/06/20 <0.03530 <0.03516 <0.03554 <0.03668 10/06/20 10/13/20 <0.03180 <0.03501 <0.03186 <0.03294 10/13/20 10/20/20 <0.00738 <0.00742 <0.00742 <0.00755 10/20/20 10/27/20 <0.02091 <0.05006 <0.05084 <0.05141 10/27/20 11/03/20 <0.03837 <0.03821 <0.03888 <0.03914 11/03/20 11/10/20 <0.03785 <0.03851 <0.03735 <0.03819 11/10/20 11/17/20 <0.02562 <0.02533 <0.02537 <0.02522 11/17/20 11/24/20 <0.04461 <0.04450 <0.01849 <0.04462 11/24/20 12/01/20 <0.04990 <0.05062 <0.04928 <0.05029 12/01/20 12/08/20 <0.04663 <0.04672 <0.04561 <0.04673 12/08/20 12/15/20 <0.04025 <0.03929 <0.01625 <0.03965 12/15/20 12/22/20 <0.04841 <0.04717 <0.04676 <0.04840 12/22/20 12/29/20 <0.06227 <0.06302 <0.02516 <0.06162

Plant: Grand Gulf Nuclear Station Year: 2020 Page 33 of 45 Annual Radiological Environmental Operating Report Page 5 of 15 Monitoring Results Tables Table 11, Air Gamma Quarterly Composite Analysis: Gamma Isotopic Units: pCi/cu.m Location Date CS-134 CS-137 REQUIRED LLD 0.05 0.06 AS-1 <0.002539 <0.00174 AS-3 <0.001585 <0.00154 02/14/20 AS-7 <0.001922 <0.002001 AS-20 <0.002483 <0.002295 AS-1 <0.002383 <0.002191 AS-3 <0.001544 <0.001507 05/15/20 AS-7 <0.001777 <0.001508 AS-20 <0.001599 <0.001395 AS-1 <0.003479 <0.002381 AS-3 08/14/20 <0.001957 <0.001658 AS-7 <0.001395 <0.001622 AS-20 <0.001787 <0.001378 AS-1 <0.001754 <0.00134 AS-3 <0.001342 <0.00154 11/13/20 AS-7 <0.001819 <0.002058 AS-20 <0.003241 <0.002657

Plant: Grand Gulf Nuclear Station Year: 2020 Page 34 of 45 Annual Radiological Environmental Operating Report Page 6 of 15 Monitoring Results Tables Table 12, Thermoluminescent Dosimeters - Inner Ring Analysis: Gamma Dose Units: mrem Annual Station 1st Qtr 2020 2nd Qtr 2020 3rd Qtr 2020 4th Qtr 2020 Mean 2020 M-16 10.8 9.1 11.3 11.6 10.7 M-19 8.5 9.9 9.9 10.0 9.0 M-21 11.2 12.5 12.5 11.9 11.4 M-22 8.3 8.5 8.5 8.6 7.9 M-23 Lost[Note 2] Lost[Note 3] 9.3 8.8 9.0 M-25 Lost[Note 2] Lost[Note 3] 8.4 8.7 8.5 M-28 10.7 8.9 12.1 11.3 10.7 M-94 10.8 8.4 10.7 10.5 10.1 M-95 6.2 5.3 7.4 7.0 6.5 M-96 7.3 6.8 9.1 8.3 7.9 M-97 7.2 5.9 7.3 8.1 7.1 M-98 10.1 9.6 14.1 12.3 11.5 M-99[Note 1] 10.2 10.3 14.6 12.4 11.9 M-100 10.0 10.2 12.1 11.0 10.8

[Note 1] - Station with highest annual mean.

[Note 2] - Reference Attachment 1, Sample Deviations, Table 8, Sample Deviations Table, Comment 1

[Note 3] - Reference Attachment 1, Sample Deviations, Table 8, Sample Deviations Table, Comment 2

Plant: Grand Gulf Nuclear Station Year: 2020 Page 35 of 45 Annual Radiological Environmental Operating Report Page 7 of 15 Monitoring Results Tables Table 13, Thermoluminescent Dosimeters - Outer Ring Analysis: Gamma Dose Units: mrem Annual Mean Station 1st Qtr 2020 2nd Qtr 2020 3rd Qtr 2020 4th Qtr 2020 2020 M-36 8.6 6.4 9.0 8.6 8.1 M-40 4.5 3.6 5.6 6.5 5.1 M-48 10.3 8.4 10.8 10.5 10.0 M-49 11.3 9.4 11.0 11.8 10.9 M-50 9.6 7.9 10.3 9.7 9.4 M-55 11.0 9.1 11.5 12.2 10.9 M-57[Note 1] 11.4 9.4 12.2 12.2 11.3

[Note 1] - Station with highest annual mean.

Table 14, Thermoluminescent Dosimeters - Special Interest Areas Analysis: Gamma Dose Units: mrem Annual Mean Station 1st Qtr 2020 2nd Qtr 2020 3rd Qtr 2020 4th Qtr 2020 2020 M-01[Note 1] 10.4 10.0 12.5 12.4 11.3 M-07 10.5 9.3 10.4 11.5 10.4 M-09 9.6 8.4 9.7 10.6 9.6 M-10 7.7 7.5 8.3 9.6 8.3 M-33 7.5 6.3 7.3 7.9 7.3 M-38 9.3 7.1 9.4 10.5 9.1 M-39 8.6 7.3 8.9 9.6 8.6

[Note 1] - Station with highest annual mean.

Table 15, Thermoluminescent Dosimeters - Control Analysis: Gamma Dose Units: mrem Annual Mean Station 1st Qtr 2020 2nd Qtr 2020 3rd Qtr 2020 4th Qtr 2020 2020 M-14 10.7 9.3 11.3 11.4 10.7

Plant: Grand Gulf Nuclear Station Year: 2020 Page 36 of 45 Annual Radiological Environmental Operating Report Attachment 2 Page 8 of 16 Monitoring Results Tables Table 16, Surface Water - Gamma Analysis: Gamma Isotopic Units: pCi/L Location Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD 15 15 30 15 30 15 30 15 15 18 60 15 MRDOWN 02/04/20 <5.151 <6.112 <14.03 <5.607 <10.59 <5.535 <11.18 <9.03 <5.711 <6.03 <25.86 <7.505 (Indicator)

MRDOWN GG 02/04/20 <5.885 <6.385 <8.826 <5.159 <10.79 <4.508 <10.26 <7.929 <4.648 <5.334 <28.09 <7.745 (Indicator)

MRUP 02/04/20 <4.311 <5.22 <10.88 <5.322 <9.462 <5.284 <7.966 <7.951 <4.976 <4.561 <28.63 <7.463 (Control)

MRUP GG 02/04/20 <5.202 <6.186 <12.85 <6.41 <10.48 <5.628 <9.314 <9.046 <5.648 <5.585 <24 <9.3 (Control)

MRDOWN 05/05/20 <7.588 <8.095 <11.28 <7.962 <17.21 <9.156 <15.85 <9.986 <9.177 <9.624 <34.82 <12.4 (Indicator)

MRUP 05/05/20 <8.903 <7.711 <16.76 <7.362 <18.89 <8.31 <12.06 <12.16 <7.108 <8.446 <37.88 <8.503 (Control)

MRDOWN 08/03/20 <7.388 <7.356 <10.37 <7.03 <10.7 <7.105 <13.41 <12.05 <7.578 <7.572 <36.87 <8.773 (Indicator)

MRUP 08/03/20 <5.591 <3.808 <11.96 <5.834 <13.33 <5.883 <8.737 <9.34 <6.914 <5.963 <30.36 <6.7 (Control)

MRDOWN GG 08/03/20 <5.423 <5.138 <10.94 <6.583 <11.46 <5.55 <9.985 <9.752 <5.383 <5.136 <25.15 <8.553 (Indicatory)

MRUP GG 08/03/20 <6.452 <4.35 <13.99 <6.877 <11.41 <5.868 <12.18 <7.899 <5 <6.565 <28.67 <11.02 (Control)

Plant: Grand Gulf Nuclear Station Year: 2020 Page 37 of 45 Annual Radiological Environmental Operating Report Attachment 2 Page 9 of 15 Monitoring Results Tables Table 16, Surface Water - Gamma Analysis: Gamma Isotopic Units: pCi/L Location Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 MRDOWN 10/27/20 <3.052 <3.42 <8.274 <3.352 <6.71 <3.424 <6.507 <9.53 <3.239 <3.689 <25.58 <8.031 (Indicator)

MRUP 10/27/20 <2.836 <2.88 <7.103 <2.583 <5.475 <3.1 <5.113 <8.007 <3.412 <2.687 <18.46 <5.315 (Control)

MRDOWN GG 10/27/20 <2.789 <3.063 <5.867 <3.35 <5.499 <2.784 <5.71 <8.299 <3.145 <2.83 <18.48 <7.159 (Indicator)

MRUP GG 10/27/20 <2.524 <2.562 <6.472 <2.751 <5.015 <2.919 <5.243 <7.319 <2.88 <2.648 <17.27 <5.737 (Control)

MRDOWN*

10/27/20 <2.51 <2.706 <5.852 <2.95 <4.812 <2.588 <4.364 <7.669 <2.453 <2.442 <16.59 <5.919 (Indicator)

MRDOWN GG*

10/27/20 <2.753 <2.868 <6.12 <3.005 <5.517 <2.945 <4.913 <7.937 <2.944 <2.897 <16.1 <6.644 (Indicator)

GG - indicates duplicate sample

• - indicates Annual Sample collected during liquid discharge

Plant: Grand Gulf Nuclear Station Year: 2020 Page 38 of 45 Annual Radiological Environmental Operating Report Page 10 of 15 Monitoring Results Tables Table 17, Surface Water - Tritium Analysis: H-3 Units: pCi/L Location Date H-3 REQUIRED LLD 3000 OUTFALL 007 01/22/20 <533 MRDOWN 02/04/20 <545 MRDOWN GG 02/04/20 <563 MRUP 02/04/20 <542 MRUP GG 02/04/20 <540 OUTFALL 007 02/19/20 1480 OUTFALL 007 GG 02/19/20 1640 OUTFALL 007 03/17/20 <491 OUTFALL 007 04/21/20 <494 OUTFALL 007 GG 04/21/20 <506 MRDOWN 05/05/20 <488 MRUP 05/05/20 <511 OUTFALL 007 05/19/20 <489 OUTFALL 007 06/16/20 <538 OUTFALL 007 06/26/20 <517 OUTFALL 007 07/21/20 <400 OUTFALL 007 GG 07/21/20 <404 MRDOWN 08/03/20 <551 MRDOWN GG 08/03/20 <551 MRUP 08/03/20 <558 MRUP GG 08/03/20 <550 OUTFALL 007 08/18/20 <517 OUTFALL 007 09/15/20 <392 OUTFALL 007 GG 09/15/20 <397 OUTFALL 007 10/20/20 <519

GNRO 2020-00012 Rev. 2020 Page 39 of 45 Annual Radiological Environmental Operating Report Page 11 of 15 Monitoring Results Tables Table 17, Surface Water - Tritium Analysis: H-3 Units: pCi/L Location Date H-3 OUTFALL 007 GG 10/20/20 <521 MRDOWN 10/27/20 <486 MRDOWN* 10/27/20 <494 MRDOWN GG 10/27/20 <503 MRDOWN GG* 10/27/20 <486 MRUP 10/27/20 <495 MRUP GG 10/27/20 <496 OUTFALL 007 11/18/20 <543 OUTFALL 007 GG 11/18/20 <535 OUTFALL 007 12/02/20 <591 OUTFALL 007 GG 12/02/20 <573 OUTFALL 007 12/15/20 <526 GG - indicates duplicate sample

• - indicates Annual Sample collected during liquid discharge

Plant: Grand Gulf Nuclear Station Year: 2020 Page 40 of 45 Annual Radiological Environmental Operating Report Attachment 2 Page 12 of 16 Monitoring Results Tables Table 18, Drinking Water - Gamma, I-131 Analysis: Gamma Isotopic, I-131 Units: pCi/L Location Date I-131 Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD 1 15 15 30 15 30 15 30 15 18 60 15 CONSTWELL 4 11/10/20 <0.918 <8.092 <4.651 <13.13 <6.476 <11.35 <4.977 <9.832 <6.963 <6.838 <31.3 <6.172 CONSTWELL 4 GG 11/10/20 <0.851 <6.461 <5.792 <13.81 <7.236 <12.68 <6.57 <8.969 <6.348 <7.277 <23.81 <7.581 PGWELL 11/10/20 <0.653 <6.648 <6.003 <12.61 <8.275 <13 <5.661 <12.83 <6.581 <6.357 <27.9 <9.853 PGWELL GG 11/10/20 <0.788 <8.209 <6.721 <12.04 <6.922 <13.45 <9.792 <11.86 <8.022 <7.867 <26.19 <10.7 GG - indicates duplicate sample

Plant: Grand Gulf Nuclear Station Year: 2020 Page 41 of 45 Annual Radiological Environmental Operating Report Page 13 of 15 Monitoring Results Tables Table 19, Drinking Water - Tritium Analysis: H-3 Units: pCi/L Location Date H-3 REQUIRED LLD 2000 CONSTWELL 4 11/10/20 <531 CONSTWELL 4 GG 11/10/20 <526 PGWELL 11/10/20 <518 PGWELL GG 11/10/20 <536 GG - indicates duplicate sample Table 20, Sediment Analysis: Gamma Isotopic Units: pCi/kg Location Date Cs-134 Cs-137 REQUIRED LLD 150 180 SEDCONT 09/10/20 <70.51 <64.27 SEDCONT GG 09/10/20 <66.61 <53.72 SEDHAM 09/10/20 <69.99 <66.05 SEDHAM GG 09/10/20 <61.7 <48.17 GG - indicates duplicate sample

Plant: Grand Gulf Nuclear Station Year: 2020 Page 42 of 45 Annual Radiological Environmental Operating Report Attachment 2 Page 14 of 15 Monitoring Results Tables Table 21, Fish Analysis: Gamma Isotopic Units: pCi/kg Collection Location Mn-54 Co-58 Fe-59 Co-60 Zn-65 Cs-134 Cs-137 Date REQUIRED LLD 130 130 260 130 260 130 150 FISHUP 09/21/20 <28.17 <32.85 <45.17 <53.67 <54.24 <51.19 <45.41 FISHDOWN 09/21/20 <29.75 <33.09 <95.58 <45.1 <62.37 <30.82 <41.33 Table 22, Food Products Analysis: Gamma Isotopic, I-131 Units: pCi/kg Location Collection Date I-131 Cs-134 Cs-137 REQUIRED LLD 60 60 80 VEG-CONT 02/21/20 <35.5 <32.42 <30.67 VEG-J 02/21/20 <45.64 <32.8 <30.17 VEG-CONT 05/19/20 <29.53 <26.97 <31.34 VEG-J 05/19/20 <28.85 <29.59 <28.42 VEG-CONT 08/19/20 <27.69 <31.52 <22.34 VEG-J 08/19/20 <25.7 <28.99 <24.17 VEG-CONT 11/16/20 <20.89 <27.29 <24.76 VEG-CONT GG 11/16/20 <25.19 <27.96 <27.47 VEG-J 11/16/20 <25.74 <28.23 <24.01 VEG-J GG 11/16/20 <30.85 <35.53 <34.3 GG - indicates duplicate sample

Plant: Grand Gulf Nuclear Station Year: 2020 Page 43 of 45 Annual Radiological Environmental Operating Report Attachment 2 Page 16 of 16 Monitoring Results Tables Table 23, Special Samples, Surface Water Analysis: Gamma Isotopic Units: pCi/L Location Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Nb-95 Zr-95 I-131 Cs-134 Cs-137 Ba-140 La-140 REQUIRED LLD 15 15 30 15 30 15 30 15 15 18 60 15 OUTFALL 007 03/21/20 <6.799 <5.552 <12.08 <6.479 <11.86 <5.479 <10.44 <8.474 <7.325 <7.322 <27.06 <6.656 OUTFALL 007 GG 03/21/20 <9.88 <6.548 <16.36 <9.058 <15.79 <7.193 <9.564 <11.14 <8.567 <8.34 <27.44 <11.27 OUTFALL 007 06/26/20 <4.388 <4.272 <10.22 <4.458 <10.77 <5.178 <7.806 <13.19 <4.138 <5.015 <26.39 <10.21 OUTFALL 007 09/29/20 <5.132 <5.811 <8.343 <6.061 <12.14 <6.53 <11.22 <11.03 <7.431 <5.289 <23.65 <9.397 OUTFALL 007 12/02/20 <5.482 <5.528 <12.06 <6.701 <12.2 <4.728 <8.601 <9.65 <4.56 <6.151 <27.92 <7.528 OUTFALL 007 GG 12/02/20 <5.669 <3.876 <10.83 <6.709 <13.21 <6.339 <8.664 <9.15 <5.86 <4.785 <26.45 <6.592 GG - indicates duplicate sample Table 24, Special Samples, Meat Analysis: Gamma Isotopic Units: pCi/kg Location Date Mn-54 Co-58 Fe-59 Co-60 Zn-65 Cs-134 Cs-137 REQUIRED LLD 130 130 260 130 260 130 150 DEER 11/13/20 <56.1 <47.13 <97.51 <56.33 <123.7 <59.17 <55.15

Plant: Grand Gulf Nuclear Station Year: 2020 Page 44 of 45 Annual Radiological Environmental Operating Report Attachment 3 Page 1 of 2 Interlaboratory Comparison Program Results TELEDYNE BROWN ENGINEERING 1.0 Summary The TBE Laboratory analyzed Performance Evaluation (PE) samples of air particulate (AP), air iodine, milk, soil, vegetation, and water matrices for various analytes. The PE samples supplied by Analytics Inc., Environmental Resource Associates (ERA) and Department of Energy (DOE)

Mixed Analyte Performance Evaluation Program (MAPEP), were evaluated against the following pre-set acceptance criteria:

A. Analytics Evaluation Criteria Analytics evaluation report provides a ratio of TBEs result and Analytics known value. Since flag values are not assigned by Analytics, TBE evaluates the reported ratios based on internal QC requirements based on the DOE MAPEP criteria.

B. ERA Evaluation Criteria ERAs evaluation report provides an acceptance range for control and warning limits with associated flag values. ERAs acceptance limits are established per the US EPA, National Environmental Laboratory Accreditation Conference (NELAC), state-specific Performance Testing (PT) program requirements or ERAs SOP for the Generation of Performance Acceptance Limits, as applicable. The acceptance limits are either determined by a regression equation specific to each analyte or a fixed percentage limit promulgated under the appropriate regulatory document.

C. DOE Evaluation Criteria MAPEPs evaluation report provides an acceptance range with associated flag values. MAPEP defines three levels of performance:

• Acceptable (flag = A) - result within +/- 20% of the reference value

• Acceptable with Warning (flag = W) - result falls in the +/- 20% to +/- 30% of the reference value

• Not Acceptable (flag = N) - bias is greater than 30% of the reference value Note: The Department of Energy (DOE) Mixed Analyte Performance Evaluation Program (MAPEP) samples are created to mimic conditions found at DOE sites which do not resemble typical environmental samples obtained at commercial nuclear power facilities.

For the TBE laboratory, 126 out of 133 analyses performed met the specified acceptance criteria. Seven analyses did not meet the specified acceptance criteria for the following reasons and were addressed through the TBE Corrective Action Program. A summary is found below:

Plant: Grand Gulf Nuclear Station Year: 2020 Page 45 of 45 Annual Radiological Environmental Operating Report Page 2 of 2 Interlaboratory Comparison Program Results

1. The MAPEP February 2020 AP U-233/234 and U-238 results were evaluated as Not Acceptable. The reported value for U-233/234 was 0.0416 +/- 0.0102 Bq/sample and the known result was 0.075 Bq/sample (acceptance range 0.053 - 0.098). The reported value for U-238 was 0.0388 +/- 0.00991 Bq/sample and the known result was 0.078 Bq/sample (acceptance range 0.055 - 0.101). This sample was run as the workgroup duplicate and had RPDs of 10.4% (U-234) and 11.7% (U-238). After the known results were obtained, the sample was relogged. The filter was completely digested with tracer added originally; the R1 results were almost identical. It was concluded that the recorded tracer amount was actually double, causing the results to be skewed. Lab worksheets have been modified to verify actual tracer amount vs. LIMS data. TBE changed vendors for this cross-check to ERA MRAD during the 2nd half of 2020. Results were acceptable at 97.8% for U-234 and 106% for U-238. (NCR 20-13)

2. The Analytics September 2020 milk Sr-89 result was evaluated as Not Acceptable. The reported value was 62.8 pCi/L and the known result was 95.4 (66%). All QC data was reviewed and there were no anomalies. This was the first failure for milk Sr-89 since 2013 and there have only been 3 upper/lower boundary warnings since that time. It is believed that there may have been some Sr-89 loss during sample prep. The December 2020 result was at 92% of the known. (NCR 20-19)

3. The ERA October 2020 water I-131 result was evaluated as Not Acceptable. The reported value was 22.9 pCi/L and the known result was 28.2 (acceptance range 23.5 - 33.1). The reported result was 81% of the known, which passes TBE QC criteria. This was the first failure for water I-131. (NCR 20-17)

4. The ERA October 2020 water Gross Alpha and Gross Beta results were evaluated as Not Acceptable. The reported/acceptable values and ranges are as follows:

Reported Known Range Gross Alpha 40.0 26.2 13.3 - 34.7 Gross Beta 47.5 69.1 48.0 - 76.0 All QC data was reviewed with no anomalies and a cause for failure could not be determined. This was the first failure for water Gross Beta. A Quick Response follow-up cross-check was analyzed as soon as possible with acceptable results at 96.8% for Gross Alpha and 102% for Gross Beta. (NCR 20-18)

5. The MAPEP August 2020 soil Ni-63 result was evaluated as Not Acceptable. The reported value was 438 +/- 21.1 Bq/kg and the known result was 980 Bq/kg (acceptance range 686 - 1274). It is believed that some Ni-63 loss occurred during the sample prep step. (NCR 20-20)

The Inter-Laboratory Comparison Program provides evidence of in control counting systems and methods, and that the laboratories are producing accurate and reliable data.