ML24116A174
| ML24116A174 | |
| Person / Time | |
|---|---|
| Site: | Millstone  |
| Issue date: | 04/24/2024 |
| From: | Armstrong L Dominion Energy Nuclear Connecticut |
| To: | Office of Nuclear Reactor Regulation, Document Control Desk |
| References | |
| 24-111 | |
| Download: ML24116A174 (1) | |
Text
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 314 Rope Ferry Road, Waterford, CT 06385 DominionEnergy.com U.S. Nuclear Regulatory Commission Attention: Document Control Desk Washington, DC 20555-0001 APR 2 4 2024 DOMINION ENERGY NUCLEAR CONNECTICUT, INC.
MILLSTONE POWER STATION UNITS 1, 2, AND 3 F,;. Dominion ii# Energy Serial No.
MPS Lie/LO Docket Nos.
License Nos.24-111 RO 50-245 50-336 50-423 DPR-21 DPR-65 NPF-49 2023 ANNUAL RADIOLOGICAL ENVIRONMENTAL OPERA TING REPORT (REOR)
This letter transmits the Annual Radiological Environmental Operating Report for the Millstone Power Station, for the period January 1, 2023, through December 31, 2023.
This satisfies the provisions of Section 5.7.2 of Millstone Power Station Unit 1 Permanently Defueled Technical Specifications (POTS), and Sections 6.9.1.6A and 6.9.1.3 of the Millstone Power Station Units 2 and 3 Technical Specifications, respectively.
Should you have any questions, please contact Mr. Dean E. Rowe at (860) 444-5292.
Sincerely,
~a~cr L. J. Armstrong Director, Nuclear Station Safety and Licensing Attachments:
1 Commitments made in this letter:
- 1. None.
cc:
U. S. Nuclear Regulatory Commission Region I 475 Allendale Rd., Suite 102 King of Prussia, PA 19406-1415 P.Longmire NRC Project Manager Millstone Unit 1 U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 5-A 10 11555 Rockville Pike Rockville, MD 20852-2738 L. A. Kauffman NRC Inspector U.S. Nuclear Regulatory Commission Region I 475 Allendale Rd., Suite 102 King of Prussia, PA 19406-1415 Nick Eckhoff NRC Inspector U.S. Nuclear Regulatory Commission Region I 475 Allendale Rd., Suite 102 King of Prussia, PA 19406-1415 R. V. Guzman Serial No.24-111 2023 Annual Radiological Environmental Operating Report Page 2 of 4 NRC Project Manager Millstone Units 2 and 3 U.S. Nuclear Regulatory Commission One White Flint North, Mail Stop 08 C2 11555 Rockville Pike Rockville, MD 20852-2738 NRC Senior Resident Inspector Millstone Power Station
Serial No.24-111 2023 Annual Radiological Environmental Operating Report Director Bureau of Air Management Monitoring & Radiation Division Department of Energy and Environmental Protection 79 Elm Street Hartford, CT 06106-5127 A. Honnellio Regional Radiation Representative (EPA Region 1, Boston)
U. S. Environmental Protection Agency (Region 1) 5 Post Office Square Suite 100 Boston, MA 02109 G. Allen Jr.
Department of Health and Human Services U. S. Food and Drug Administration 140 Shrewsbury Street, Suite 1 Boylston, MA 01501 M. Bachman Executive Director Connecticut Siting Council 10 Franklin Square New Britain, CT 06051 J.P. Kelley Waterford-East Lyme Shellfish Commission Waterford Town Hall 15 Rope Ferry Road, Waterford, CT 06385 Justin Folkwein American Nuclear Insurers 95 Glastonbury Blvd.
Glastonbury, CT 06033 David. H. Carey Connecticut Department of Agriculture Aquaculture Division P. 0. Box 97 Millford, CT 06460 Page 3 of 4
Rob Brule First Selectman Town of Waterford 15 Rope Ferry Road Waterford Town Hall Waterford, CT 06385 Daniel Cunningham First Selectman Town of East Lyme PO Box 519 Niantic, CT 06357 Jane Strudwick Head of Acquisitions & Discovery University Of Connecticut Library 369 Fairfield Way, Unit 1005 Storrs, CT 06269-1005 Serial No.24-111 2023 Annual Radiological Environmental Operating Report Page 4 of 4
ATTACHMENT 1 Serial No.24-111 Docket Nos. 50-245 50-336 50-423 License Nos. DPR-21 DPR-65 NPF-49 2023 ANNUAL RADIOLOGICAL ENVIRONMENT AL OPERA TING REPORT MILLSTONE POWER STATION UNITS 1, 2, AND 3 DOMINION ENERGY NUCLEAR CONNECTICUT, INC. (DENC)
Millstone Power Station 2023 Radiological Environmental Operating Report
}
January 1, 2023 - December 31, 2023 Dominion Energy Nuclear Connecticut, Inc.
Unit License Docket 1
DPR-21 50-245 2
DPR-65 50-336 3
NPF-49 50-423 Dominion Energy
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 ANNUAL RADIOLOGICAL ENVIRONMENT AL OPERATING REPORT MILLSTONE POWER STATION RADIOLOGICAL ENVIRONMENTAL MONITORING PROGRAM 2023 Millstone Power Station Unit 1, DOCKET NO. 50-245 Millstone Power Station Unit 2, DOCKET NO. 50-336 Millstone Power Station Unit 3, DOCKET NO. 50-423 Dominion Energy Nuclear Connecticut, Inc.
Waterford, Connecticut
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023
~ TABLE OF CONTENTS EXECUTIVE
SUMMARY
...................................................................................................................... i
- 1. INTRODUCTION................................................................................................... 1-1
- 1. 1.
Overview....................................................................................................... 1-1 1.2.
Radiation and Radioactivity.......................................................................... 1-1 1.3.
Sources of Radiation.................................................................................... 1-2 1.4.
Nuclear Reactor Operations......................................................................... 1-3 1.5.
Radioactive Effluent Control......................................................................... 1-8 1.6.
Radiological Impact on Humans................................................................... 1-1 O
- 2. PROGRAM DESCRIPTION.................................................................................. 2-1 2.1 Sampling Schedule and Locations................................................................... 2-1 2.2 Samples Collected During Report Period......................................................... 2-8 2.3 Required Samples Not Collected During the Report Period............................. 2-8
- 3. RADIOCHEMICAL RESULTS............................................................................... 3-1 3.1 Summary Tables............................................................................................. 3-1 3.2 Data Tables.................................................................................................... 3-7
- 4. DISCUSSION OF RESULTS................................................................................ 4-1 4.1 Gamma Exposure Rate (Table 1)............................................................... 4-1 4.2 Air Particulate Gross Beta Radioactivity (Table 2)..................................... 4-4 4.3 Air Iodine (Table 3).................................................................................... 4-5 4.4 Air Particulate Gamma (Table 4 )................................................................ 4-5 4.5 Soil (Table 5)............................................................................................. 4-5 4.6 Cow Milk (Table 6)..................................................................................... 4-6 4.7 WellWater (Table7).................................................................................. 4-6 4.8 Fruits and Vegetables (Table 8)................................................................. 4-6 4.9 Broad Leaf Vegetation (Table 9)................................................................ 4-6 4.10 Seawater (Table 10).................................................................................. 4-6 4.11 Bottom Sediment (Table 11)...................................................................... 4-8 4.12 Aquatic Flora (Table 12)............................................................................. 4-8 4.13 Fish (Table 13)........................................................................................... 4-8 4.14 Oysters (Table 14)..................................................................................... 4-8 4.15 Clams (Table 15)....................................................................................... 4-8 4.16 Lobsters (Table 16).................................................................................... 4-8
- 5. REFERENCES...................................................................................................... 5-1 APPENDIX A - LAND USE CENSUS FOR 2023...................................................... A-1 APPENDIX B -
SUMMARY
OF INTERLABORATORY COMPARISONS................. B-1 APPENDIX C - ERRATUM........................................................................................ C-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station EXECUTIVE
SUMMARY
INTRODUCTION Annual Radiological Environmental Operating Report 2023 This report summarizes the results of the Radiological Environmental Monitoring Program (REMP) conducted in the vicinity of the Millstone Power Station (MPS) during the period from January 1, 2023, to December 31, 2023. This document has been prepared in accordance with the requirements of the separate MPS Unit 1 (MPS1) Permanently Defueled Technical Specifications and the Technical Specifications for Millstone Units 2 and 3 (MPS2 and MPS3).
The REMP has been established to monitor the radiation and radioactivity released to the environment as a result of MPS operation. This program, initiated in April 1967, includes the collection, analysis, and evaluation of radiological data to assess the impact of MPS on the environment and on the general public.
SAMPLING AND ANALYSIS The environmental sampling media collected in the vicinity of MPS and at distant locations included aquatic, atmospheric, and terrestrial samples. These samples were air particulate filters, charcoal cartridges, soil, well water, broadleaf vegetation, fruits and vegetables, seawater, bottom sediment, aquatic flora, fish, oysters, clams, and lobsters.
During 2023, there were 528 samples collected from the atmospheric, aquatic, and terrestrial environments. In addition, 172 exposure measurements were obtained using environmental thermo luminescent dosimeters (TLDs). A discussion of all discrepancies from the sample collection requirements in the MPS Radiological Effluent Monitoring and Offsite Dose Calculation Manual (REMODCM) is given in Section 2.3 of this report.
Teledyne Brown Engineering, Inc. of Knoxville, Tennessee performed the sample analyses and Environmental Dosimetry Company of Sterling, Massachusetts, performed the TLD analyses.
LAND USE CENSUS The annual land use census in the vicinity of MPS was conducted as required by the MPS REMODCM. To determine the dairy exposure pathway, a list of cow milk and goat milk locations is established. The list of cow milk locations is identified by a review of the annual registration information obtained from the State of Connecticut Department of Agriculture. The list of goat milk locations is identified by the information obtained from the American Dairy Goat Association list and by inspections performed in the field. Although broadleaf sampling was performed and may be used in lieu of a garden census, gardens were included in the 2023 census. Only vegetable gardens having an area of more than 500 square feet were identified. Due to the difficulty of measuring individual gardens, the nearest garden within each directional sector identified by a drive-by survey is listed. However, for dose calculation, garden distances are based on nearest resident assuming that a resident may plant a new garden. This gives a more conservative dose estimate.
RADIOLOGICAL IMPACT TO THE ENVIRONMENT The radionuclides detected in some samples were from non-station, naturally occurring radionuclides.
All terrestrial samples collected as part of the MPS REMP did not show any station related isotopes.
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 The seawater exiting the stations quarry is monitored for all station generated radionuclides.
Tritium was only found in seawater onsite inside the mixing zone of the quarry discharge at levels that were expected from routine station operation.
Offsite ambient radiation measurements using environmental TLDs beyond the site boundary ranged between 38 - 103 milliroentgens ( mrem) per year. The range of ambient radiation levels observed with the TLDs is consistent with natural background radiation levels for Connecticut.
RADIOLOGICAL IMPACT TO THE GENERAL PUBLIC During 2023, radiation doses to the general public as a result of Millstone's operation continued to be well below the federal limits and much less than the dose due to other sources of man-made (e.g., X-rays, medical) and naturally occurring (e.g., cosmic, radon) radiation.
The calculated total body (whole body) dose to the maximally exposed member of the public from radioactive effluents and ambient radiation resulting from MPS operations for 2023 was approximately 0.2 mrem for the year.
This conservative estimate is well below the Environmental Protection Agency's (EPA) annual dose limit to any member of the general public and is a fraction of a percent of the typical dose received from natural and other sources of man-made radiation.
CONCLUSIONS The 2023 REMP for MPS resulted in the collection and analysis of 700 environmental samples and measurements. The data obtained were used to determine the impact of Millstone's operation on the environment and on the general public.
An evaluation of direct radiation measurements, environmental sample analyses, and dose calculations indicates all applicable federal criteria were met with margin. Furthermore, radiation levels and the consequential dose from station operation were small in comparison to those attributed to naturally occurring and man-made background radiation.
Based on this information, there is no significant radiological impact on the environment or on the general public due to Millstone's operation. The 2023 REMP samples results are consistent with previous years with no trends evident.
ii
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station
- 1. INTRODUCTION Annual Radiological Environmental Operating Report 2023 This section provides an overview of the MPS REMP. It also includes background information to allow a reader to have an informed understanding of radiation and nuclear power operation.
1.1 Overview The 2023 REMP performed by Dominion Energy Nuclear Connecticut (DENG) for MPS is discussed in this report. Since the operation of a nuclear power station results in the release of small amounts of radioactivity and low levels of radiation, the Nuclear Regulatory Commission (NRC) requires by regulations and technical specifications that a program be established to monitor radiation and radioactivity in the environment (References 1, 6, 9, 10, & 11 ). This report published annually per Millstone's Technical Specifications (section 5.7.2 for MPS1, section 6.9.1.6a for MPS2 and Section 6.9.1.3 for MPS3), summarizes the results of measurements of radiation and radioactivity in the environment in the vicinity of the MPS and at distant locations during the period January 1, 2023, to December 31, 2023.
The REMP consists of taking radiation measurements and collecting samples from the environment, analyzing them for radioactivity content, and interpreting the results.
With emphasis on the critical radiation exposure pathways to humans, samples from the aquatic, atmospheric, and terrestrial environments are collected. These samples include, but are not limited to air, soil, well water, broadleaf vegetation, fruits, vegetables, seawater, bottom sediment, aquatic flora, fish, oysters, clams, and lobsters.
Thermoluminescent dosimeters (TLDs) are placed in the environment to measure gamma radiation levels. The TLDs are processed, and the environmental samples are analyzed to measure the very low levels of radiation and radioactivity present in the environment as a result of MPS operation and other natural and man-made sources. These results are reviewed by Millstone's radiological staff and have been reported semiannually or annually to the NRC and others for over 30 years.
To more fully understand how a nuclear power station impacts humans and the environment, background information on radiation and radioactivity, natural and man-made sources of radiation, reactor operations, radioactive effluent controls, and radiological impact on humans is provided. It is believed that this information will assist the reader in understanding the radiological impact on the environment and humans from the operation of Millstone.
1.2 Radiation and Radioactivity All matter is made of atoms. Nuclear radiation is energy or particles that are given off from atoms in an excited state (e.g., unstable, radioactive atoms).
Radioactive material exists naturally and has always been a part of our environment. The earth's crust, for example, contains radioactive uranium, radium, thorium, and potassium.
Some radioactivity is a result of fallout from nuclear weapons testing. Examples of radioactive fallout that could be present in environmental samples are cesium-137 and strontium-90.
Some examples of radioactive materials released from a nuclear power station are hydrogen-3 (tritium),
cesium-137, iodine-131, strontium-90, and cobalt-60.
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Radiation is measured in units of mrem, much like temperature is measured in degrees. A mrem is a measure of the biological effect of the energy deposited in tissue. The letter 'm' is for 'milli',
or one-thousandth of a 'rem'. The word 'rem' is an acronym for roentgen equivalent man. One rem is equal to a 'rad' multiplied by factors to account for type of radiation and distribution within the body. The word 'rad' is an acronym for radiation absorbed dose. One rad is equal to the absorption of 100 ergs of energy per gram of tissue. The natural and man-made radiation dose received in one year by the average American is 300 to 600 mrem (References 2, 3, 4 & 5). The per capita dose has increased since the early 1980's because of the increased usage of medical procedures involving exposure to radiation (Reference 3).
Radioactivity is measured in Curies. Levels of radioactivity commonly seen in the environment are typically a small fraction of a Curie, therefore radioactivity in the. environment is typically measured in picocuries. One picocurie (pCi) is one-trillionth of a Curie and is equal to 0.037 disintegrations per second (2.22 disintegrations per minute).
1.3 Sources of Radiation As mentioned previously, naturally occurring radioactivity has always been a part of our environment. Table 1.3-1 shows the sources and doses of radiation from natural and man-made sources.
Table 1.3-1 Rd' f S
a Ia I0n ources an orrespon lnQ,pproxIma e d C d'
A t D oses NATURAL MAN-MADE Radiation Dose Source (mrem/year)
Internal, inhalation(2) 228 External, space 33 Internal, ingestion 29 External, terrestrial 21 Approximate Total 311 (1) information from References 3 and 4 (2) from radon and thoron Source MedicaI(3l Consumer(4l Industrial, security, educational, research Occupational Weapons Fallout Nuclear Power Stations Approximate Total (1)
Radiation Dose (mrem/year) 300 12.3 0.3 0.5
< 1
< 1 314 (3) includes computerized tomography (147 mrem), nuclear medicine (77 mrem), interventional fluoroscopy (43 mrem) and conventional radiography and fluoroscopy (33 mrem)
(4) primarily from cigarette smoking (4.6 mrem), commercial air travel (3.4 mrem), building materials (3.5 mrem) and mining and agriculture (0.8 mrem) 1-2
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Cosmic radiation (external, space) from the sun and outer space penetrates the earth's atmosphere and continuously bombards us with rays and charged particles. Some of this cosmic radiation interacts with gases and particles in the atmosphere, making them radioactive. These radioactive byproducts from cosmic ray bombardment are referred to as cosmogenic radionuclides. Isotopes such as beryllium-? and carbon-14 are formed in this way. Exposure to cosmic and cosmogenic sources of radioactivity results in about 33 mrem of radiation dose per year.
Additionally, natural radioactivity is in our body and in the food, we eat (about 29 mrem/year),
the ground we walk on (about 21 mrem/year) and the air we breathe (about 228 mrem/year).
Most of a person's annual dose results from exposure to radon and thoron in the air we breathe. These gases and their radioactive decay products arise from the decay of naturally occurring uranium, thorium and radium in the soil and building products such as brick, stone, and concrete. Radon and thoron levels vary greatly with location, primarily due to changes in the concentration of uranium and thorium in the soil. Residents at some locations in Colorado, New York, Pennsylvania, New Jersey, and even Connecticut have a higher annual dose because of higher levels of radon/thoron gases in these areas. In total, these various sources of naturally occurring radiation and radioactivity contribute to a total dose of about 311 mrem per year.
In addition to natural radiation, we are normally exposed to radiation from a number of man-made sources. The single largest doses from man-made sources result from therapeutic and diagnostic applications of x-rays and radiopharmaceuticals. The annual dose to an individual in the United States from medical and dental exposure is approximately 300 mrem.
Consumer products/uses, such as cigarettes, building materials and commercial air travel contribute about 13 mrem/year. Much smaller doses result from weapons fallout (less than 1 mrem/year) and nuclear power stations (less than 1 mrem/year). Typically, the average person in the United States receives approximately 314 mrem per year from man-made sources.
1.4 Nuclear Reactor Operations MPS generates about 2100 megawatts of electricity at full power, which provides approximately one-third of the power consumed in the State of Connecticut. MPS2 and MPS3 are pressurized water reactors (MPS1, which is permanently shut down, was a boiling water reactor). The nuclear station is located on an approximate 500-acre site about three miles (five kilometers) west of New London, Connecticut. Commercial operation of MPS2 began in December 1975 and MPS3 in May 1986.
In 2023, MPS had two planned refueling outages, MP2 in April and MP3 in October. The annual capacity factor for MPS2 was 71.90% and for MPS3 was 76.90%.
Nuclear-generated electricity is produced by many of the same techniques used for conventional oil and coal-generated electricity. Both systems use heat to boil water to produce steam. The steam turns a turbine, which turns a generator, producing electricity. In both cases, the steam passes through a condenser where it changes back into water and re-circulates back through the system (see Figure 1.4-1 ). The cooling water source for MPS is the Niantic Bay.
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 The key difference between nuclear power and conventional power is the source of heat used to boil the water. Conventional stations burn fossil fuels in a boiler, while nuclear stations use uranium fission in a nuclear reactor.
Inside the reactor, a nuclear reaction called fission takes place. Particles, called neutrons, strike the nucleus of a uranium-235 atom, causing it to split into fragments called radioactive fission products. The splitting of the atoms releases both heat and more neutrons. The newly released neutrons then collide with and split other uranium atoms, thus making more heat and releasing even more neutrons, and on and on until the uranium fuel is depleted or spent. This process is called a chain reaction. When this chain reaction is self-sustaining, the reactor is called "critical."
The operation of a nuclear reactor results in the release of small amounts of radioactivity and low levels of radiation. The radioactivity originates from two major sources, radioactive fission products and radioactive activation products. Radioactive fission products, as illustrated in Figure 1.4-1, originate from the fissioning of the nuclear fuel. These fission products get into the reactor coolant from their release by minute amounts of uranium on the outside surfaces of the fuel cladding, by diffusion through the fuel pellets and cladding and, on occasion, through defects or failures in the fuel cladding. These fission products circulate along with the reactor coolant water and will deposit on the internal surfaces of pipes and equipment. The radioactive fission products on the pipes and equipment emit radiation. Examples of some fission products are krypton-85 (Kr-85), strontium-90 (Sr-90), iodine-131 (1-131 ), xenon-133 (Xe-133), and cesium-137 (Cs-137).
Pressurized water reactor-a common type of Light Water Reactor
{LWR)
- -------*coNDENSER COOLING WATER
-TAKING WASTE HEAT TO THE ENVIRONMENT Figure 1.4-1: SIMPLIFIED DIAGRAM OF A PRESSURIZED WATER REACTOR 1-4
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Nuclear Fission: fission is the splitting of atoms (e.g., uranium-235) by a neutron to release heat and more neutrons, creating a chain reaction. Radiation and fission products are by-products of the process as illustrated in Figure 1.4-2.
Neutron Uranium Fission Products Uranium i*~
"-~
Uranium 1..,..
Neutrons Fission Products Figure 1.4-2: Radioactive Fission Product Formation 1-5
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Radioactive activation products (Figure 1.4-3), on the other hand, originate from two sources.
The first is by neutron bombardment of the hydrogen, oxygen and other gas (helium, argon, nitrogen) molecules in the reactor cooling water. The second is a result of the fact that the internals of any piping system or component are subject to minute yet constant corrosion from the reactor cooling water. These minute metallic particles (for example: nickel, iron, cobalt, or magnesium) are transported through the reactor core into the fuel region, where neutrons may react with the nuclei of these particles, producing radioactive products. Therefore, activation products are nothing more than ordinary naturally-occurring atoms that are made unstable or radioactive by neutron bombardment. These activation products circulate along with the reactor coolant water and will deposit on the internal surfaces of pipes and equipment. The radioactive activation products on the pipes and equipment emit radiation. Examples of some activation products are manganese-54 (Mn-54 ), iron-59 (Fe-59), cobalt-60 (Co-60), and zinc-65 (Zn-65).
0 Neutron collision with Co-59 Stable Cobalt Nucleus Co-60 Radioactive Cobalt Nucleus Figure 1.4-3: Radioactive Activation Product Formation At MPS there are five independent protective barriers that confine these radioactive materials.
These five barriers are:
fuel pellets; fuel cladding; reactor vessel and associated piping and equipment; primary containment; and secondary containment (enclosure building).
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 The ceramic uranium fuel pellets provide the first barrier. Most of the radioactive fission products are either physically trapped or chemically bound between the uranium atoms, where they will remain. However, a few fission products that are volatile or gaseous may diffuse through the fuel pellets into small gaps between the pellets and the fuel cladding.
The second barrier, the fuel cladding, consists of zirconium alloy tubes that confine the fuel pellets. The small gaps between the fuel and the cladding contain the noble gases and volatile iodines that are types of radioactive fission products. This radioactivity can diffuse to a small extent through the fuel cladding into the reactor coolant water. Radioactivity can also escape into coolant water through cladding defects and failures.
The third barrier consists of the reactor pressure vessel, steel piping and equipment that confine the reactor cooling water. The reactor pressure vessel, which holds the reactor fuel, is typically a steel tank 40 feet high by 14 feet in diameter with walls about five to nine inches thick. These vessels and associated piping provide containment for radioactivity in the primary coolant and the reactor core. However, during the course of operations and maintenance, small amounts of radioactive fission and activation products can escape through valve leaks or upon breaching of the primary coolant system for maintenance.
The fourth barrier is the primary containment. It is a cylindrical enclosure with approximately five-foot thick steel reinforced concrete walls lined by steel on the inside. During operation the containment is closed but small amounts of radioactivity may be released from primary containment by venting during operation to maintain proper containment pressure. During maintenance and refueling outages containment is open and small amounts of radioactivity is released during this time when the fuel has been moved out of the reactor cavity in containment.
The fifth barrier is the secondary containment or enclosure building. The enclosure building is a steel building that surrounds the primary containment. This barrier is an additional safety feature at Millstone's reactor units to contain radioactivity that may escape from the primary containment.
This enclosure building is equipped with a filtered ventilation system that is used when needed to reduce the radioactivity that escapes from the primary containment.
The five barriers confine most of the radioactive fission and activation products. However, small amounts of radioactivity do escape via mechanical failures and maintenance on valves, piping, and equipment associated with the reactor cooling water system. The small amounts of radioactive liquids and gases that do escape the various containment systems are further controlled by the liquid purification and ventilation filtration systems. The control of radioactive effluents at MPS will be discussed in more detail in the next section.
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 1.5 Radioactive Effluent Control Annual Radiological Environmental Operating Report 2023 The small amounts of radioactive liquids and gases that might escape the first two barriers are processed in the liquid and gaseous waste treatment systems, then monitored for radioactivity, and released only if the radioactivity levels are below the federal release limits.
Radioactivity released from the liquid effluent system to the environment is limited, controlled and monitored by a variety of systems and procedures which include:
reactor water cleanup system; liquid radioactive waste treatment system; sampling and analysis of the liquid radioactive waste tanks; and liquid waste effluent discharge radioactivity monitor.
The purpose of the reactor water cleanup system is to continuously purify the reactor cooling water by removing radioactive atoms and non-radioactive impurities that may become activated by neutron bombardment. A slip stream of the reactor coolant water is diverted from the primary coolant system and is directed through ion exchange resins where radioactive elements, dissolved and suspended in the water, are removed through chemical processes.
The net effect is a substantial reduction of the radioactive material that is present in the primary coolant water and consequently the amount of radioactive material that might escape from the system.
Reactor cooling water that might escape the primary cooling system and other radioactive water sources are collected in floor and equipment drains. These drains direct this radioactive liquid waste to large holdup tanks. The liquid waste collected in the tanks is purified again using the liquid radioactive waste treatment system, which consists of a filter and ion exchange resins.
Processing of liquid radioactive waste results in large reductions of radioactivity in liquids discharged into Niantic Bay. Wastes processed through liquid radioactive waste treatment can be purified and, in some cases, re-used in station systems.
Prior to release, the radioactivity in any liquid radioactive waste tank is sampled and analyzed to determine if the level of radioactivity is below the release limits and to quantify the total amount of radioactive liquid effluent that will be released. If the levels are below the federal release limits, the tank is drained to the liquid effluent discharge header.
This liquid waste effluent discharge line is provided with a shielded radioactivity monitor. This detector is connected to a radiation level meter and a recorder in the Control Room. The radiation alarm is set so that the detector will alarm before radioactivity levels exceed the release limits. In addition to the alarm function, the radiation monitor also signals both discharge valves to close thus terminating the discharge release to the environment. Gamma spectroscopy analysis, tritium analysis and the effluent radiation monitors prevent any liquid radioactivity from being released in excess of release rate and total activity limits. An audible alarm notifies the Control Room operator that this has occurred.
Some liquid waste sources, which have a low potential for containing radioactivity, and/or may contain very low levels of contamination, may be *discharged directly to the environment.
One such source of liquid is the turbine building sump. However, periodic representative samples are collected for analysis of radioactivity content to track the amounts of radioactivity being discharged.
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 The preceding discussion illustrates that many controls exist to reduce the radioactive liquid effluents released to the environment to as far below the release limits as is reasonably achievable.
Radioactive releases from the radioactive gaseous effluent system to the environment are limited, controlled, and monitored by a variety of systems and procedures which include:
containment building ventilation system; containment building radioactivity monitors; sampling and analysis of containment building vent and purge effluents; process gas treatment system; auxiliary building (and engineered safeguards and fuel building for MPS3) ventilation system; MPS stack and units' vent effluent radioactivity monitors; sampling and analysis of MPS stack and units' vent effluents; process radiation monitors; and steam jet air ejector (SJAE) monitor.
The primary sources of gaseous radioactive waste are degassing of the primary coolant, gaseous liquid drains, and gaseous vents. Additional sources of gaseous waste activity include ventilation air released from the auxiliary building and purging and venting of the containment building. The radiation level meter and recorders for the effluent radioactivity monitors are located in the Control Room. The station process computer aids in tracking the monitor readings. To supplement the information continuously provided by the detector, air samples are taken periodically from the units' containments, MPS stack and units' vents. These samples are analyzed to quantify the total amount of radioactive gases, radioactive iodine, radioactive particulate, and tritium released in gaseous effluents.
Gases from the primary coolant are held up in waste gas decay tanks for decay at MPS2.
Gaseous waste at MPS3 is purified through a process gas system, consisting of high-efficiency particulate air filters and charcoal absorber beds. Gases from periodic venting of the MPS2 containment are released through a similar process system (Enclosure Building Filtration System) while gases from the MPS3 containment vacuum pumps are released without treatment.
If necessary, MPS3 containment air can be filtered by an internal particulate and charcoal treatment system. Containment purges (purge is the forced ventilation process while containment vents are pressure releases) for MPS2 are filtered by high-efficiency particulate filters while at MPS3 these are not normally filtered. If necessary, particulate and charcoal filters can be used for these purges.
Normally, for MPS2, the air released from the unit vent is from the ventilation of the auxiliary (which includes the fuel pool), service and enclosure buildings. For MPS2, fuel pool and enclosure building ventilation can be redirected to the MPS Site Stack. Normally, for MPS3, the air released from the unit vent is from the ventilation of the auxiliary, fuel, service, waste disposal and enclosure buildings. For MPS3, enclosure building ventilation can be redirected to the MPS Site Stack.
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Therefore, for both liquid and gaseous releases, radioactive effluent cor;itrol systems exist to collect and purify the radioactive effluents in order to reduce releases to the environment to as low as is reasonably achievable. The effluents are always monitored, sampled and analyzed to make sure that radioactivity levels are below the release limits. If the release limits are being approached, isolation valves are closed to stop the release and ensure that federal regulatory limits are always met.
1.6 Radiological Impact on Humans The final step in the effluent control process is the determination of the radiological dose impact to humans and comparison with the federal dose limits to the public. As mentioned previously, the purpose of continuous radiation monitoring and periodic sampling and analysis is to measure the quantities of radioactivity being released to determine compliance with the radioactivity release limits. This is the first stage for assessing releases to the environment.
The second stage is calculation of the dose impact to the general public from MP S's radioactive effluents. The purpose of this calculation is to periodically assess the dose to the general public resulting from radioactive effluents to ensure that the dose is being maintained as far below the federal dose limit as is reasonably achievable. This is the second stage for assessing releases to the environment.
The types and quantities of radioactive liquid and gaseous effluents released from MPS during each year are reported to the NRC annually in the Radiological Effluent Release Report (RERR).
Similar to this report, the RERR is submitted annually to the NRC. The liquid and gaseous effluents were well below the federal release limits and were a small percentage of the MPS REMODCM effluent control limits.
The measurements of the physical and chemical nature of the effluents are used to determine how the radionuclides will interact with the environment and how they can result in radiation exposure to humans. The environmental interaction mechanisms depend upon factors such as the hydrological (water) and meteorological (atmospheric) characteristics in the area.
Information on the water flow, wind speed, wind direction, and atmospheric mixing characteristics are used to estimate how radioactivity will distribute and disperse in the ocean and the atmosphere.
The most important type of information that is used to evaluate the radiological impact on humans is data on the use of the environment. Information on fish and shellfish consumption, boating usage, beach usage, locations of cows and goats, locations of residences, locations of gardens, and other usage information are utilized to estimate the amount of radiation and radioactivity received by the general public.
The radiation exposure pathway to humans is the path radioactivity takes from its release point at MPS to its effect on man. The movement of radioactivity through the environment and its transport to humans is portrayed in Figure 1.6-1.
1-10
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 EXAMPLES OF Millstone's RADIATION EXPOSURE PATHWAYS LIQUID EFFLUENTS
- 1. SHORELINE DIRECT RADIATION (FISHING, PICNIC.ING) ~
- 2. DIRECT RADIATION (IMMERSION IN OCEAN, (OAT;, SWIMMING)
INGESTION
~~****~ **
- ~
~ ***~
d If ll~lt~~,
- 1*:***i*i*i*i*i*i*i*i*i*****i*i***i***************** **l
- 3. DIRECT RADIATION (STATION),
- 2. AIR INHALATION
(/ 1. DIRECT RADIATION
- ~
(AIR SUBMERSION)
~
V
- 5. CONSUMPTION (VEGETATION)
~
~
DEPOSITION
~
DEPOSITION Figure 1.6-1: Radiation Exposure Pathways 1-11
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 There are four pathways in which liquid effluents affect humans:
external radiation from liquid effluents that deposits and accumulates on the shoreline; external radiation during boating from radioactivity in ocean water; external radiation from immersion in ocean water containing radioactivity; and internal radiation from consumption of fish and shellfish containing radioactivity absorbed from the liquid effluents.
There are six major pathways in which gaseous effluents affect humans:
external radiation from immersion in an airborne plume of radioactivity; external radiation from shine from an overhead, airborne plume of radioactivity; internal radiation from inhalation of airborne radioactivity; external radiation from deposition of radioactive effluents on the ground; internal radiation from consumption of vegetation containing radioactivity deposited on the vegetation from airborne deposition and absorbed from the soil due to ground deposition of radioactive effluents; and internal radiation from consumption of milk and meat containing radioactivity deposited on forage that is eaten by cattle and other livestock.
Drinking water is not a pathway of exposure for radioactivity released in liquid or gaseous effluents from Millstone. All liquid effluents are released to either Long Island Sound or Niantic Bay. Both are saltwater bodies which are not used as sources of drinking water. The closest reservoir is Lake Konomoc, 6.5 miles from Millstone. Radioactivity deposited in the reservoir from MPS gaseous effluents would not yield a significant dose to the public compared to doses from the six major pathways listed.
Ambient (direct) radiation emitted from sources of radioactivity at MPS comes from low-level radioactive waste being processed and stored at the site prior to shipping and disposal. Also, the operation of the Independent Spent Fuel Storage Installation (ISFSI) which began in 2005 results in a small amount of direct radiation at the site boundary.
The radiological dose impact on humans is based both on effluent analyses and modeling and on direct measurements of radiation and radioactivity in the environment. However, the operation of MPS results in releases of only small amounts of radioactivity, and, as a result of dilution in the atmosphere and ocean, even the most sensitive radioactivity measurement and analysis techniques cannot usually detect these tiny amounts of radioactivity above that which is naturally present in the environment. Therefore, radiation doses are calculated using radioactive effluent release data and computerized dose calculations that are based on conservative NRC-recommended models that tend to result in over-estimates of the resulting dose. These computerized dose calculations are performed by DENC personnel. These computer codes use the guidelines and methodology set forth by the NRC in Regulatory Guide 1.109 (Reference 7).
The dose calculations are specified in the Millstone's REMODCM (Reference 8), which has been reviewed by the NRC.
It should be emphasized that the conservative assumptions made in the computer code calculations; the maximum hypothetical dose to an individual is considerably higher than the dose that would actually be received by a real individual.
1-12
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 After dose calculations are performed, the results are compared to the dose limits for the public as specified in NRC's technical specifications for MPS (References 9-11 ).
The technical specifications limits for the dose to a member of the general public from radioactive material in liquid effluents released to unrestricted areas are:
less than or equal to 3 mrem per year to the total body; and, less than or equal to 10 mrem per year to any organ.
The technical specifications limits for dose due to release of radioactivity in gaseous effluents is restricted to:
less than or equal to 1 0 mrad per year for gamma radiation from noble gases; less than or equal to 20 mrad per year for beta radiation from noble gases; and less than or equal to 15 mrem per year to any organ from iodine-131, iodine-133, tritium, and all particulate radionuclides with half-lives greater than 8 days.
The Technical Specifications limits for total dose from all three MPS units due to release of radioactivity in gaseous and liquid effluents and direct radiation is restricted to:
less than or equal to 25 mrem per year to the total body; less than or equal to 75 mrem per year to the thyroid; and less than or equal to 25 mrem per year to any other organ.
1-13
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station
- 2. PROGRAM DESCRIPTION 2.1 Sampling Schedule and Locations Annual Radiological Environmental Operating Report 2023 The sample locations, types, and frequency of analysis are given in Tables 2.1-1 and 2.1-2 and are shown in Figures 2.1-1 and 2.1-2. The program as described in Table 2.1-1 lists the required samples collected as specified in the REMODCM, as well as any other extra samples collected under the program.
2-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Table 2,1-1 Environmental Monjtorjng Program sampling Types and Locations
- Distance, No.-
Direction From Type*
Location Name Release Point**
Sample Media 1-1 Onsite - NAP Parking Lot N 0.6Mi, NNW TLD, Air Particulate, Iodine, Vegetation 2-1 Onsite - Weather Shack 0.3Mi, S TLD, Air Particulate, Iodine 3-1 Onsite - Bird Sanctuary 0.3 Mi, NE TLD, Air Particulate, Iodine, Soil 4-1 Onsite - Albacore Drive 1.0 Mi, N TLD, Air Particulate, Iodine, Soil 5-1 Onsite - Quarry East 0.1 Mi, SSE TLD 6-1 Onsite - Quarry Discharge 0.3 Mi, SSE TLD 7-1 Onsite - Env. Lab Dock 0.3 Mi, SE TLD 8-1 Onsite - Env. Lab 0.3 Mi, SE TLD 9-1 Onsite - Bay Point Beach 0.4 Mi, W TLD 10-1 Goshen Fire Dept.
1.2 Mi, E TLD, Air Particulate, Iodine, Vegetation 11-1 Great Neck Country Club 1.6 Mi, ENE TLD, Air Particulate, Iodine 13-C Mystic, CT 11.5 Mi, ENE TLD 14-C Ledyard, CT 12.0 Mi, NE TLD, Soil 15-C Norwich, CT 14.0 Mi, N TLD, Air Particulate, Iodine 16-C Old Lyme, CT - Halls Rd.
8.8Mi,W TLD 17-1 Site Boundary 0.5 Mi, NE Vegetation 25-1 Fruits & Vegetables
< 10 Miles Vegetation 25-X Fruits & Vegetables
< 10Miles Vegetation 26-C Fruits & Vegetables
> 10 Miles Vegetation 27-1 East Lyme Police Dept.
1.7Mi, WNW TLD, Air Particulate, Iodine 28-1 Two Tree Island 1 0.8 Mi, SSE Fish 1 29-1 West Jordan Cove 1
- 0.5 Mi, ENE to ESE Clams, Fucus, Fish 1 31-1 Niantic Shoals 1.8 Mi, NW Bottom Sediment, Clams 32-1 Vicinity of Discharge 1-2 Bottom Sediment, Fish 1, Seawater, Aquatic Flora 33-1 Seaside Point 1.8 Mi, ESE Bottom Sediment 34-1 Thames River Yacht Club 4.0 Mi, ENE Bottom Sediment 35-1 Niantic Bay
- 0.5 Mi, SSW to W Lobster, Fish1, Aquatic Flora 36-C Black Point 2.7Mi, WSW Aquatic Flora 37-C Giant's Neck 3.5Mi, WSW Bottom Sediment, Seawater 41-1 Waterford - Myrock Avenue 3.2 Mi, ENE TLD 42-1 East Lyme - Billow Road 2.4 Mi, WSW TLD 43-1 East Lyme-Old Black Point 2.6 Mi, SW TLD 44-1 Onsite - Schoolhouse 0.1 Mi, NNE TLD 45-1 Onsite - Access Road #1 0.5Mi, NNW TLD 46-1 Old Lyme - Hillcrest Ave.
4.6Mi, WSW TLD 47-1 East Lyme - W. Main St.
4.5Mi, W TLD 48-1 East Lyme - Corey & Roxbury 3.4Mi, WNW TLD 49-1 East Lyme - Society Rd.
3.6Mi, NW TLD 50-1 East Lyme - Manwaring Rd &
2.1 Mi, W TLD Terrace Ave 51-1 East Lyme - Smith Ave.
1.5Mi, NW TLD 52-1 Waterford - River Rd.
1.1 Mi, NNW TLD 53-1 Waterford - Gardiners Wood Rd 1.4 Mi, NNE TLD 55-1 Waterford - Magonk Point 1.8 Mi, ESE TLD 56-1 New London - Ocean & Mott 3.7 Mi, E TLD Ave.
- 1. Fish required to be sampled from one of three other locations (#28, #29 or #32).
- 2. Vicinity of discharge includes the Quarry and shoreline area from Fox Island to western point of Red Barn recreation Area and Offshore out to 500 feet.
Footnotes:
- I = Indicator; C = Control, X - Extra - sample not required by the REMODCM
- = The release points are the Millstone Stack for terrestrial location and the end of the quarry for aquatic location.
2-2
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Table 2,1-1 Environmental Monjtorjng program Sampling Types and Locations (Continues)
No.-
Distance, Direction From Type1 Location Name Release Point2 Sample Media 57-1 New London - Ocean Ave.
3.6 Mi, ENE TLD 59-1 Waterford -Miner Ave.
3.4 Mi, NNE TLD 60-1 Waterford-Parkway South&Cross 4.0Mi, N TLD 61-1 Waterford-Oil Mill&Boston Post 4.3Mi, NNW TLD 62-1 East Lyme - Columbus Ave.
1.9Mi, WNW TLD 63-1 Waterford - Gardiners Wood &
0.8 Mi, NE TLD Jordon Cove 64-1 Waterford - Shore Rd.
1.1 Mi, ENE TLD 65-1 Waterford - Boston Post Rd.
3.2 Mi, NE TLD 66-X NAP Parking Lot - Fit Center 0.4 Mi, NW TLD 71-1 1-MW-XFMR-03 Onsite Well Water 72-1 MW-GPl-1 Onsite Well Water 73-X Site Switchyard Fence 0.3 Mi, N TLD 74-X Ball Field Foul Pole 0.6Mi, N TLD 75-X Waterford - Windward Way &
0.5 Mi, NE TLD Shotgun 76-X ISFSl-1 Up-gradient of ISFSI Well Water 77-X ISFSl-2 Down-gradient of ISFSI Well Water 78-X ISFSl-3 Down-gradient of ISFSI Well Water 79-1 M3-MW-1 Onsite Well Water 81-1 S2-MW-1 Onsite Well Water 82-1 MW-6B Onsite Well Water 83-1 S3-MW-2 Onsite Well Water 89-C Aquatic background
>4 miles of discharge Lobster
- 1. Fish required to be sampled from one of three other locations (#28, #29 or #32).
- 2. Vicinity of discharge includes the Quarry and shoreline area from Fox Island to western point of Red Barn recreation Area and Offshore out to 500 feet.
Footnotes:
- I = Indicator; C = Control, X - Extra - sample not required by the REMODCM
- = The release points are the Millstone Stack for terrestrial location and the end of the quarry for aquatic location.
2-3
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Table 2,1-2 Reqyjred Sampling frequency & Type of Analysis Exposure Pathway No. of Sampling & Collection Type and Frequency and/or Sample Locations Frequency of Analysis
- 1.
Gamma Dose-391 Quarterly Gamma Dose - Quarterly Environmental TLD
- 2.
Airborne Particulate 8
Continuous sampler - filter change Gross Beta - Every two every two weeks weeks Gamma Spectrum
- Quarterly on composite (by location), and on individual sample if gross beta is greater than 10 I
times the mean of the weekly control station's gross beta results
- 3.
Airborne Iodine 8
Continuous sampler -
canister 1-131 - Every two weeks change every two weeks
- 4.
Vegetation 5
One sample near middle and one Gamma Isotopic on each near end of growing season sample
- 5.
Milk - Refer to Table 2.1-2.1 below
- 6.
Sea Water 2
Continuous sampler with a Gamma Isotopic and monthly collection at indicator Tritium on each sample.
location. Quarterly at control location - Composite of 6 weekly grab samples.
- 7.
Well Water 6
Semiannual Gamma Isotopic and Tritium on each sample
- 8.
Bottom Sediment 5
Semiannual Gamma Isotopic on each sample
- 9.
Soil 3
Annually Gamma Isotopic on each sample
- 10.
Fin Fish 2
Semiannual Gamma Isotopic on each (edible portion) sample
- 11.
Aquatic flora (fucus) 4 Quarterly Gamma isotopic on each sample
- 13.
Clams 2
Semiannual Gamma Isotopic on each (edible portion) sample
- 14.
Lobster 2
Semiannual Gamma Isotopic on each (edible portion) sample Footnotes
Oysters were previously Sample#12, REMODCM revision 27.
2-4
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Table 2,1-2,1 Milk Sampling Reqyjrements Number of Locations and Sampling & Collection Type and Frequency Sampling Criteria Frequency of Analysis If milk location(s) are available, obtain samples from Semimonthly when animals Gamma Isotopic and milking animals from up to three locations within 3 miles are on pasture; Monthly, for 1-131 analysis on each (5 km) distance having the highest dose potential. If non---pasture producers.
sample there are none, then one sample from milking animals in each of three areas between 3 to 5 miles (5 to 8 km) distant where doses are calculated to greater than 1 mrem per year. One sample from milking animals at a control location 9 to 18 miles (15 to 30 km) distant and in the least prevalent wind direction.
If milk location(s) are not available, obtain samples of Monthly, if available, or at Gamma Isotopic and three different kinds of broad leaf vegetation grown harvest, (a) 1-131 analysis on each nearest each of two different offsite locations of highest sample predicted annual average ground level D/Q Footnotes (a) Harvest consists of one sample near the middle and one sample near the end of the growing season.
2-5
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 figure 2,1-1, "loner JLP, Air, Grass, Soil, and Aquatic Locations" r
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 f jgyre 2,1-2, "Outer ILP and Aquatic Locations"
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2-7
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 2.2 Samples Collected During Report Period The following table summarizes the number of samples of each type collected and analyzed during 2023:
Iabl~ 2,2-j Bffllle Samgl~~ ~Qll~"t~~ i* 2Q2J Number of Number of Technical Technical Sample Type Specification Specification Required Samples Required Samples Analyzed Gamma Exposure 156 156 (Environmental TLD)
Air Particulates 208 208 Air Iodine 208 208 Soil 3
3 Milk 12 0
Well Water 12 12 Vegetation 10 10 Sea Water 16 16 Bottom Sediment 10 10 Aquatic Flora 16 16 Fish 4
4 Oysters 0
0 Clams 4
4 Lobster 4
4 Total All Types 651 639 2.3 Required Samples Not Collected During the Report Period During 2023 all required samples were obtained except for Milk.
Number of Extra Samples Analyzed 16 0
0 0
0 24 1
0 0
4 0
4 0
0 49 The 2023 Land Use Census did not locate any milk farms producers within ten miles of Millstone Power Station. As a substitute for milk sampleps, strontium analysis of air samples and gamma analysis of broad leaf vegetation were performed. This fulfills the requirements for Milk sampling as listed in Table 2.1-2.1 of this report, "Milk Sampling Requirements" 2-8
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station
- 3. RADIOCHEMICAL RESULTS 3.1 Summary Table Annual Radiological Environmental Operating Report 2023 In accordance with the REMODCM,Section I.F.1, a summary table of the radiochemical results has been prepared and is presented on the following pages. The mean and range recorded are based only upon detectable measurements.
A more detailed analysis of the data is given in Section 4.0 where a discussion of the variations in the data explains many aspects that are not evident in the Summary Table because of the basic limitation of data summaries. The data summaries include the extra ("X") samples collected throughout the year. These samples are taken to enhance the monitoring program or replace samples from required locations when they are not available.
Furthermore, in accordance with the REMODCM,Section I.E.3, an inter-laboratory comparison was performed by Teledyne Brown Engineering Environmental Services (TBE-ES) as part of their quality assurance program for environmental monitoring in order to demonstrate that the results are reasonably valid (Appendix B). Quality Control of radioanalyses involves TBE-ES internal process control program and independent third party programs administered by Analytics and Environmental Resource Associates (ERA) and Department of Energy's (DOE)
Mixed Analyte Performance Evaluation Program (MAPEP).
The Teledyne inter-laboratory comparison report concluded that 124 out of 131 quality assurance analyses performed met the specified acceptance criteria. Seven analyses did not meet the specified acceptance criteria addressed in Teledyne Non-Conformance Reports (NCRs), listed in Appendix B. A review of the Teledyne NCRs was performed and none of the seven analyses failures were found to have impacted any of Millstone samples results and data accuracy, addressed and dispositioned in the Millstone Corrective Action Program.
3-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Medium or Pathway Sampled (Units)
Direct Radiation TLD (uR/hr)
Air Iodine (pCi/m 3)
Air Particulate (pCi/m 3)
Soil (pCilg dry)
Cow Milk (pCi/1)
RADIOLOCIAL ENVIRONMENT MONITORING PROGRAM
SUMMARY
MILLSTONE POWER STATION Dockets 50-245, 50-336 & 50-423 2023 Indicator Control Locations Location with Highest Mean Locations Analysis Total LLD*
Number I
Number Type Number Mean Location I Distance Number Mean (Range)
Number Direction Mean (Range)
(Range)
Gamma 172 NA 156 8,9 0.3 Mi./0.04 Mi.
4/4 16 Dose 7.8 SE/W 11.3/11.3 8.0 (4.3-11.8)
(10.7-11.6)/(10.7-11.8)
(5.5-10.0) 1-131 208 0.07 182 NA NA
<LLD 26
<LLD
<LLD GR-8 208 0.01 182 3
.03 Mi.
26 26 0.014 NE 0.015 0.015 (0. 005-0. 030)
(0.008-0.029)
(0.008-0.027)
SR-89 32 0.1 28 NA NA
<LLD 4
<LLD
<LLD SR-90 32 0.01 28 NA NA
<LLD 4
<LLD
<LLD GAMMA BE-7 32 NA 28 0.6Mi.
4 4
0.0876 NNW 0.0961 0.0829 (0.0547-0.1199)
(0.0718-0.1072)
(0.0548-0.1023)
Other Note 2
<LLD NA NA
<LLD
<LLD Gammas GAMMA 3
K-40 NA 2
14 12.0 Mi.
15.110 NE 21.020 21.020 (11.890-18.330)
(21.020)
(21.020)
CS-137 0.18 1/2 4
1.0 Mi.
0.281 N
0.281
<LLD (0.281)
AC-228 NA 2
14 12.0Mi.
0.885 NE 1.400 1.400 (0.673-1.097)
(1.400)
(1,400)
Other Note 3
<LLD NA NA
<LLD
<LLD Gammas SR-89 10 SR-90 2
GAMMA Milk was not available for collection in 2023, as a substitute, K-40 NA Strontium Analysis of Air Particulate filters was performed Other Note 4 Gammas 3-2
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Medium or Pathway Sampled (Units)
Goat Milk (pCi/1)
Well Water (pCill)
Fruits & Vegetables (pCi/g v1el)
Broad Leaf Vegetation (pCilg oot)
RADIOLOCIAL ENVIRONMENT MONITORING PROGRAM
SUMMARY
MILLSTONE POWER STATION Dockets 50-245, 50-336 & 50-423 2023 Indicator Locations Location with Highest Mean Analysis Total LLD*
Number I
Type Number Mean Location I Distance Number (Range)
Number Direction Mean (Range)
SR-89 10 SR-90 2
Control Locations Number Mean (Range)
GAMMA Milk was not available for collection in 2023, as a substitute, K-40 NA Strontium Analysis of Air Particulate filters was performed Other Note4 Gammas H-3 36 2000 36 NA NA
<LLD NA
<LLD GAMMA 36 K-40 NA 36 NA NA
<LLD NA
<LLD Other Note 5
<LLD NA NA
<LLD NA Gammas GAMMA 11 K-40 NA 6
25 Within 10 Miles 5
5 1.830 1.826 1.783 (1.038-3.133)
(1.038-3.133)
(0. 832-02. 792)
Other Note6
<LLD NA NA
<LLD
<LLD Gammas GAMMA 8
BE-7 NA 4/6 10 1.2Mi.
1/2 2
1.772 E
2.820 1.327 (0.520-2.823)
(2.820)
(0.406-2.247)
K-40 NA 6
26 Beyond 10 miles 2
2 2.649 3.414 3.414 (1.971-3.682)
(3.115-3.713)
(3.115-3.713)
Other Note6
<LLD NA NA
<LLD
<LLD Gammas 3-3
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Medium or Pathway Sampled (Units)
Sea Water (pCi/1)
Bottom Sediment (pCilg dry)
Aquatic Flora (pCilg \\\\el)
RADIOLOCIAL ENVIRONMENT MONITORING PROGRAM
SUMMARY
MILLSTONE POWER STATION Dockets 50-245, 50-336 & 50-423 2023 Indicator Locations Location with Highest Mean Analysis Total LLD*
Number I
Type Number Mean Location I Distance Number (Range)
Number Direction Mean (Range)
H-3 16 3000 11/12 32
< 0.1 Mi 11/12 879 879 (266-1560)
(266-1560)
GAMMA 16 K-40 NA 12 32
< 0.1 Mi 12 303 303 (164-411)
(164-411)
Other Note 5
<LLD NA NA
<LLD Gammas GAMMA 10 K-40 NA 8
32
< 0.1 Mi 2
13.94 15.26 (11.18-17.47)
(13.05-17.47)
Ac-228 NA 2/8 31 1.8Mi.
2 2.746 NW 2.746 (2.396-3.096)
(2.396-3.096)
Other Note 3
<LLD NA NA
<LLD Gammas GAMMA 16 BE-7 NA 12 NA NA
<LLD
<LLD K-40 NA 12 32
< 0.1 Mi 4
6.0802 6.3468 (5.2070-6.9170)
(5.2070-6.9170) 1-131 0.06 12 NA NA
<LLD
<LLD Other Note 6
<LLD NA NA
<LLD Gammas 3-4 Control Locations Number Mean (Range)
<LLD 4
266 (216-308)
<LLD 2
14.87 (14.48-15.26)
<LLD
<LLD 4
<LLD 4
5.4830 (3.8110-6.8910) 4
<LLD
<LLD
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Medium or Pathway Sampled (Units)
Fish - Other (pCilg oot)
Oysters (pCi/g 11et)
Clams (pCilg oot)
Lobster (pCi/g oot)
RADIOLOCIAL ENVIRONMENT MONITORING PROGRAM
SUMMARY
MILLSTONE POWER STATION Dockets 50-245, 50-336 & 50-423 2023 Indicator Locations Location with Highest Mean Analysis Total LLD*
Number I
Type Number Mean Location I Distance Number (Range)
Number Direction Mean (Range)
GAMMA 4
K-40 NA 4
29 0.4Mi.
3.768 NNE 4.196 (2.818-4.203)
(4.196)
Other Notes
<LLD NA NA
<LLD Gammas GAMMA 4
K-40 NA 1/2 31 1.8Mi.
1/2 2.068 NW 2.068 (2.068)
(2.068)
Other Note 8
<LLD NA NA
<LLD Gammas GAMMA 4
K-40 NA 4
31 1.8Mi.
2 2.011 NW 2.080 (1.839-2.122)
(2.038-2.122) other Note 8
<LLD NA NA
<LLD Gammas GAMMA 4
K-40 NA 2
89
>4.0 miles 2
2.265 2.508 (1.984-2.546)
(2.230-2. 785)
Other Note 8
<LLD NA NA
<LLD Gammas 3-5 Control Locations Number Mean (Range)
NA NA 2
1.749 (1.458-2.039)
<LLD NA NA 2
2.508 (2.230-2. 785)
<LLD
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station NOTES FOR
SUMMARY
TABLE Annual Radiological Environmental Operating Report 2023 1 - (*) The required LLD is the smallest concentration of radioactivity that will be detected with 95% confidence that the activity is real. See detailed discussion below.
2 - LLDs for air particulate gamma are 0.05 pCi/M3 for Cs-134 and 0.06 pCi/M3 for Cs-137.
3 - LLD for soil and sediment gamma is 0.15 pCi/g for Cs-134.
4 - LLDs for milk gamma are 1 pCi/I for 1-131, 15 pCi/I for Cs-134, 18 pCi/I for Cs-137, 70 pCi/I for Ba-140 and 25 pCi/I for La-140.
5 - LLDs for water gamma are 15 pCi/I for Mn-54, Co-58, Co-60, Nb-95, 1-131, Cs-134 and La-140; 30 pCi/I for Fe-59, Zn-65 and Zr-95; 18 pCi/I for Cs-137 and 60 pCi/I for Ba-140.
6 - LLDs for fruits & vegetables, broadleaf vegetation and aquatic flora for gamma are 0.06 pCi/M3 for 1-131, 0.06 pCi/M3 for Cs-134 and 0.08 pCi/M3 for Cs-137.
7 - LLDs for other gamma are 0.06 pCi/g for Cs-134 and 1-131.
8 - LLDs for fish and shellfish for gammas are 0.13 pCi/g for Mn-54, Co-58, Co-60 and Cs-134; 0.26 pCi/g for Fe-59 and Zn-65; 0.15 pCi/g for Cs-137; and 0.93 pCi/g for 1-131.
Discussion of LLD The LLD at a confidence level of 95% is the smallest concentration of radioactive material in a sample that will be detected with a 5% probability of falsely concluding that a blank observation represents a "real" signal.
For a particular measurement system (which may include radiochemical separation):
LLD = ____
4_._66_S_b ---
E
- V
- 2.22
- Y
- exp (-J./j_t)
LLD is the lower limit of detection as defined above (as pCi per unit mass or volume)
Sh is the standard deviation of the background counting rate or of the counting rate of a blank sample as appropriate (as counts per minute)
E is the counting efficiency (as counts per transformation)
V is the sample size (in units of mass or volume) 2.22 is the number of transformations per minute per picoCurie Y
is the fractional radiochemical yield (when applicable)
"A, is the radioactive decay constant for the particular radionuclide flt is the elapsed time between sample collection (or end of the sample collection period) and time of counting The LLD is defined as "a priori" (before the fact) limit representing the capability of a measurement system and not an "a posteriori" (after the fact) limit for a particular measurement.
Analyses were performed in such a manner that the stated LLDs were achieved under routine conditions. Occasionally background fluctuations, unavoidably small sample sizes, the presence of interfering nuclides, or other uncontrollable circumstances may have rendered these a priori LLDs unachievable. In such cases, the contributing factors are identified and described in this report. As shown in the equation above, for composite samples taken over a period of time, the LLD is decayed to the end of the sample period.
3-6
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 3.2 Data Tables Annual Radiological Environmental Operating Report 2023 The data reported in this section are results of analyses on all samples. All gamma exposure rates (Table 1) and air beta results (Table 2) are positive because of natural radioactivity. For all other results positive results are shown as balded type. Results are considered positive when the measured value exceeds 1.5 times the listed 2cr error (i.e., the measured value exceeds 3cr).
The reported error is two times the standard deviation (2cr) of the net activity. Unless otherwise noted, the overall error (counting, sample size, chemistry, errors, etc.) is estimated to be 2 to 5 times that listed. Because of counting statistics, negative values, zeros and numbers below the Minimum Detectable Level (MDL) are statistically valid pieces of data. For the purposes of this report, in order to indicate any background biases, all the valid data are presented. This practice was recommended by Health and Safety Laboratory (HASL) ("Reporting of Analytical Results from HASL," letter by Leo B. Higginbotham), NUREG 0475 and NUREG/CR-4007 (Sept. 1984).
Data are given according to sample type as indicated below.
- 1.
Gamma Exposure Rate
- 2.
Air Particulates, Gross Beta Radioactivity
- 3.
Air Particulates, Airborne 1-131
- 4.
Air Particulates, Gamma Spectra
- 5.
Soil
- 6.
Milk
- 7.
Well Water
- 8.
Fruits & Vegetables
- 9.
Broad Leaf Vegetation
- 10.
Seawater
- 11.
Bottom Sediment
- 12.
Aquatic Flora (Fucus)
- 13.
Fin Fish
- 14.
Oysters
- 15.
Clams
- 16.
Lobster 3-7
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station PERIOD 1
2 3
(+/-)
(+/-)
(+/-)
1Q 8.2 0.2 9.6 0.4 7.2 0.2 2Q 8.3 0.3 11.6 0.5 7.4 0.3 3Q 7.8 0.4 11.3 0.5 7.4 0.3 4Q 7.5 0.4 10.6 0.5 6.9 0.4 PERIOD 13C 14C 15C
(+/-)
(+/-)
(+/-)
1Q 9.0 0.2 9.4 0.3 7.7 0.2 2Q 8.8 0.4 10.0 0.4 7.6 0.3 3Q 8.8 0.3 9.3 0.4 7.9 0.4 4Q 8.5 0.4 9.0 0.4 7.1 0.3 PERIOD 47 48 49
(+/-)
(+/-)
(+/-)
1Q 8.1 0.2 9.3 0.4 8.1 0.3 2Q 7.7 0.5 9.1 0.6 7.6 0.3 3Q 8.0 0.3 8.8 0.3 7.6 0.3 4Q 7.3 0.3 8.4 0.4 7.4 0.3 PERIOD 60 61 62
(+/-)
(+/-)
(+/-)
1Q 6.4 0.3 6.5 0.2 9.6 0.3 2Q 6.3 0.3 6.4 0.3 9.2 0.5 3Q 6.2 0.2 6.7 0.4 9.2 0.3 4Q 6.1 0.4 6.0 0.3 8.7 0.4 TABLE 1 QUARTERLY GAMMA EXPOSURE RATE (uR/hr)*
LOCATIONS 4
5 6
7
(+/-)
(+/-)
(+/-)
(+/-)
8.5 0.3 9.6 0.3 8.8 0.3 4.9 0.2 8.1 0.3 9.9 0.4 8.8 0.5 4.7 0.4 7.8 0.3 10.2 0.4 8.4 0.3 4.8 0.3 7.8 0.4 9.1 0.5 8.1 0.3 4.3 0.3 16C 27 41 42
(+/-)
(+/-)
(+/-)
(+/-)
6.8 0.3 7.9 0.3 7.5 0.2 7.4 0.3 5.8 0.3 7.8 0.3 7.4 0.3 7.6 0.4 6.3 0.2 7.7 0.3 7.0 0.3 7.7 0.3 5.5 0.3 7.1 0.4 6.2 0.3 6.9 0.3 50 51 52 53
(+/-)
(+/-)
(+/-)
(+/-)
7.4 0.3 7.0 0.2 7.4 0.4 7.5 0.3 7.1 0.3 6.4 0.3 6.9 0.3 7.6 0.5 7.5 0.3 7.0 0.3 7.2 0.4 7.4 0.3 7.1 0.4 5.8 0.3 6.6 0.3 6.9 0.3 63 64 65 66
(+/-)
(+/-)
(+/-)
(+/-)
9.0 0.3 7.6 0.2 8.1 0.3 7.6 0.2 8.6 0.5 7.2 0.3 7.9 0.5 7.5 0.3 9.2 0.5 7.2 0.4 7.7 0.3 7.0 0.3 8.3 0.3 6.8 0.3 7.6 0.4 6.9 0.3 8
(+/-)
11.5 0.3 11.6 0.4 11.4 0.4 10.7 0.4 43
(+/-)
7.4 0.2 7.5 0.3 7.2 0.4 7.0 0.3 55
(+/-)
7.7 0.3 7.3 0.3 7.5 0.3 7.1 0.4 73
(+/-)
7.7 0.3 7.6 0.3 7.5 0.4 7.3 0.3
- READINGS ARE THE AVERAGE OF MULTI CaSo4(Tm) PHOSPHOR ELEMENTS WITHIN ONE PANASONIC TLD BADGE ERRORS ARE TWO SIGMA AND INCLUDE COUNTING, TRANSIT, READER AND FADE UNCERTAINTIES C= Control location, Background location 3-8 Annual Radiological Environmental Operating Report 2023 9
10 11
(+/-)
(+/-)
(+/-)
11.4 0.3 10.9 0.3 7.3 0.4 11.8 0.4 10.3 0.6 7.2 0.3 11.3 0.4 9.4 0.4 7.5 0.3 10.7 0.5 9.4 0.4 6.6 0.3 44 45 46
(+/-)
(+/-)
(+/-)
7.8 0.3 7.5 0.3 8.7 0.4 7.7 0.5 7.4 0.3 8.2 0.4 8.0 0.4 7.2 0.3 8.1 0.3 7.5 0.3 6.8 0.3 7.5 0.4 56 57 59
(+/-)
(+/-)
(+/-)
7.9 0.3 7.1 0.2 7.6 0.2 8.0 0.3 6.9 0.3 7.8 0.4 8.0 0.3 6.6 0.2 7.7 0.3 9.6 0.4 6.6 0.4 7.3 0.3 74 75
(+/-)
(+/-)
7.5 0.2 6.8 0.2 7.4 0.5 6.4 0.3 7.5 0.3 6.4 0.4 7.1 0.3 6.4 0.3
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 TABLE 2 AIR PARTICULATES GROSS BET A RADIOACTIVITY (pCi/m 3
)
LOCATIONS PERIOD ENDING 1
2 3
4 10 11 27 15C
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
01/17/23 0.013 0.002 0.013 0.002 0.011 0.002 0.011 0.002 0.014 0.002 0.012 0.002 0.013 0.002 0.014 0.002 01/31/23 0.010 0.002 0.012 0.002 0.012 0.002 0.011 0.002 0.011 0.002 0.012 0.002 0.013 0.002 0.011 0.002 02/14/23 0.018 0.002 0.016 0.002 0.017 0.002 0.016 0.002 0.018 0.002 0.020 0.002 0.017 0.002 0.016 0.002 02/27/23 0.014 0.002 0.014 0.002 0.015 0.002 0.013 0.002 0.013 0.002 0.016 0.002 0.014 0.002 0.015 0.002 03/13/23 0.014 0.002 0.010 0.002 0.010 0.002 0.010 0.002 0.011 0.002 0.009 0.002 0.012 0.002 0.011 0.002 03/28/23 0.013 0.002 0.012 0.002 0.015 0.002 0.013 0.002 0.016 0.002 0.013 0.002 0.013 0.002 0.015 0.002 04/11/23 0.017 0.002 0.016 0.002 0.018 0.002 0.022 0.003 0.020 0.002 0.018 0.002 0.018 0.002 0.021 0.002 04/25/23 0.014 0.002 0.014 0.002 0.013 0.002 0.012 0.002 0.012 0.002 0.013 0.002 0.013 0.002 0.013 0.002 05/09/23 0.008 0.002 0.008 0.002 0.008 0.002 0.007 0.002 0.005 0.002 0.008 0.002 0.007 0.002 0.007 0.002 05/23/23 0.011 0.002 0.012 0.002 0.013 0.002 0.012 0.002 0.012 0.002 0.012 0.002 0.013 0.002 0.013 0.002 06/06/23 0.008 0.001 0.008 0.002 0.008 0.001 0.006 0.001 0.007 0.001 0.007 0.002 0.008 0.001 0.008 0.001 06/20/23 0.011 0.002 0.010 0.002 0.013 0.002 0.011 0.002 0.012 0.002 0.011 0.002 0.011 0.002 0.011 0.002 07/05/23 0.009 0.002 0.010 0.002 0.009 0.001 0.009 0.002 0.009 0.001 0.010 0.002 0.006 0.001 0.010 0.002 07/18/23 0.015 0.002 0.015 0.002 0.015 0.002 0.018 0.002 0.016 0.002 0.019 0.003 0.016 0.002 0.018 0.002 08/01/23 0.017 0.002 0.018 0.002 0.014 0.002 0.016 0.002 0.015 0.002 0.016 0.002 0.017 0.002 0.015 0.002 08/15/23 0.014 0.002 0.015 0.002 0.015 0.002 0.014 0.002 0.015 0.002 0.015 0.002 0.013 0.002 0.015 0.002 08/29/23 0.013 0.002 0.015 0.002 0.014 0.002 0.014 0.002 0.013 0.002 0.013 0.002 0.013 0.002 0.012 0.002 09/12/23 0.030 0.003 0.029 0.003 0.029 0.003 0.028 0.003 0.029 0.003 0.029 0.003 0.030 0.003 0.027 0.003 09/26/23 0.012 0.002 0.012 0.002 0.013 0.002 0.014 0.002 0.012 0.002 0.010 0.002 0.012 0.002 0.012 0.002 10/11/23 0.020 0.002 0.017 0.002 0.019 0.002 0.019 0.002 0.019 0.002 0.018 0.002 0.019 0.002 0.019 0.002 10/24/23 0.010 0.002 0.010 0.002 0.011 0.002 0.008 0.002 0.011 0.002 0.010 0.002 0.010 0.002 0.010 0.002 11/07/23 0.019 0.002 0.021 0.002 0.022 0.002 0.020 0.002 0.020 0.002 0.022 0.002 0.020 0.002 0.021 0.002 11/20/23 0.016 0.002 0.018 0.002 0.018 0.002 0.015 0.002 0.017 0.002 0.017 0.002 0.018 0.002 0.021 0.002 12/05/23 0.017 0.002 0.016 0.002 0.017 0.002 0.017 0.002 0.016 0.002 0.015 0.002 0.015 0.002 0.016 0.002 12/20/23 0.017 0.002 0.018 0.002 0.016 0.002 0.016 0.002 0.016 0.002 0.018 0.002 0.017 0.002 0.016 0.002 01/02/24 0.010 0.002 0.012 0.002 0.012 0.002 0.009 0.002 0.010 0.002 0.009 0.002 0.012 0.002 0.011 0.002 C= Control location, Background location 3-9
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 TABLE 3 AIRBORNE IODINE (pCi/m 3)
LOCATIONS PERIOD ENDING 1
2 3
4 10 11 27 15C
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/ -)
(+/-)
(+/ -)
01/17/23
-0.005 0.030
-0.004 0.025
-0.004 0.025
-0.004 0.025
-0.013 0.018
-0.014 0.019
-0.014 0.019
-0.008 0.011 01/31 /23
-0.002 0.025
-0.002 0.020
-0.002 0.022
-0.002 0.021
-0.007 0.015
-0.008 0.016
-0.008 0.016
-0.003 0.007 02/14/23
-0.005 0.013
-0.004 0.010
-0.004 0.011
-0.004 0.012
-0.008 0.011
-0.008 0.011
-0.008 0.011
-0.007 0.010 02/27/23
-0.012 0.026
-0.009 0.019
-0.011 0.022
-0.011 0.022
-0.007 0.027
-0.007 0.028
-0.007 0.029
-0.003 0.011 03/13/23 0.042 0.031 0.033 0.025 0.038. 0.028 0.038 0.028
-0.013 0.023
-0.014 0.025
-0.013 0.023
-0.013 0.022 03/28/23
-0.004 0.018
-0.003 0.016
-0.004 0.018
-0.004 0.017
-0.006 0.016
-0.006 0.017
-0.002 0.006
-0.006 0.015 04/11 /23
-0.014 0.023
-0.012 0.019
-0.014 0.022
-0.007 0.012
-0.005 0.022
-0.005 0.025
-0.002 0.009
-0.005 0.022 04/25/23 0.005 0.022 0.005 0.022 0.005 0.021 0.004 0.017
-0.008 0.023
-0.009 0.025
-0.008 0.022
-0.008 0.023 05/09/23
-0.015 0.022
-0.017 0.024
-0.015 0.022
-0.016 0.023
-0.004 0.018
-0.004 0.019
-0.004 0.017
-0.004 0.018 05/23/23
-0.002 0.019
-0.002 0.022
-0.002 0.019
-0.002 0.020 0.003 0.019 0.003 0.020 0.003 0.017 0.003 0.018 06/06/23
-0.009 0.017
-0.010 0.021
-0.009 0.018
-0.009 0.018
-0.007 0.021
-0.008 0.023
-0.006 0.018
-0.007 0.020 06/20/23
-0.011 0.023
-0.013 0.027
-0.011 0.023
-0.011 0.024
-0.004 0.020
-0.005 0.023
-0.004 0.020
-0.004 0.019 07/05/23
-0.009 0.022
-0.011 0.026
-0.009 0.021
-0.009 0.022 0.004 0.012 0.005 0.014 0.004 0.012 0.002 0.005 07/18/23 0.000 0.011 0.000 0.012 0.000 0.011 0.000 0.011
-0.004 0.007
-0.005 0.009
-0.004 0.007
-0.004 0.007 08/01 /23 0.004 0.016 0.005 0.017 0.005 0.017 0.005 0.017
-0.006 0.016
-0.008 0.019
-0.006 0.016
-0.006 0.016 08/15/23 0.010 0.023 0.010 0.025 0.011 0.025 0.010 0.025
-0.012 0.021
-0.014 0.025
-0.012 0.022
-0.012 0.022 08/29/23
-0.009 0.011
-0.010 0.012
-0.010 0.012
-0.010 0.012 0.018 0.018 0.022 0.022 0.017 0.018 0.018 0.019 09/12/23 0.000 0.018 0.000 0.019 0.000 0.019 0.000 0.019
-0.007 0.008
-0.016 0.018
-0.014 0.015
-0.014 0.015 09/26/23 0.003 0.011 0.003 0.011 0.003 0.012 0.003 0.011
-0.003 0.018
-0.004 0.023
-0.003 0.018
-0.003 0.019 10/11/23 0.006 0.011 0.006 0.011 0.006 0.012 0.006 0.012 0.004 0.012 0.005 0.015 0.004 0.012 0.004 0.012 10/24/23 0.009 0.011 0.010 0.012 0.010 0.012 0.011 0.012 0.003 0.009 0.003 0.010 0.003 0.009 0.003 0.010 11/07/23 0.007 0.019 0.008 0.020 0.008 0.021 0.008 0.021
-0.011 0.023
-0.011 0.023
-0.011 0.023
-0.012 0.024 11/20/23
-0.002 0.019
-0.002 0.020
-0.002 0.021
-0.002 0.021
-0.008 0.018
-0.008 0.018
-0.008 0.018
-0.008 0.019 12/05/23
-0.006 0.012
-0.006 0.013
-0.007 0.014
-0.006 0.013
-0.001 0.012
-0.001 0.012
-0.001 0.012
-0.001 0.012 12/20/23
-0.008 0.012
-0.009 0.013
-0.009 0.013
-0.009 0.013
-0.010 0.019
-0.010 0.019
-0.010 0.019
-0.010 0.019 01 /02/24
-0.001 0.018
-0.001 0.020
-0.001 0.021
-0.001 0.020
-0.009 0.015
-0.009 0.015
-0.009 0.015
-0.009 0.015 C= Control location, Background location 3-10
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE 4 AIR PARTICULATES (pCi/m 3
)
GAMMA SPECTRA - QTR 1 (01/03/23 - 03/28/23)
LOCATION Sr-89
(+/-)
0.0079 0.0136 2
0.0121 0.0122 3
0.0055 0.0108 4
-0.0035 0.0076 10 0.0026 0.0107 11
-0.0058 0.0090 27
-0.0140 0.0129 15C 0.0095 0.0119 LOCATION Nb-95 ~
-0.0003 0.0028 2
0.0005 0.001 2 3
0.0013 0.0021 4
-0.0020 0.0027 10 0.0018 0.0023 11 0.0002 0.0019 27
-0.0025 0.0022 15C 0.0023 0.0020 LOCATION Ce-141
(+/-)
-0.0010 0.0060 2
0.0022 0.0034 3
-0.0019 0.0036 4
0.0004 0.0058 10
-0.0020 0.0053 11 0.0003 0.0041 27
-0.0026 0.0044 15C 0.0000 0.0039 C= Control location, Background location Results in bold type are positi1.e.
(+/-)
0.0005 0.0021
-0.0014 0.0015 0.0004 0.0014 0.0018 0.0016 0.0003 0.0015 0.0011 0.0019 0.0008 0.0021 0.0004 0.0017 Zr-95
(+/-)
0.0039 0.0049
-0.0004 0.0027
-0.0009 0.0030 0.0003 0.0042 0.0006 0.0046 0.0003 0.0035 0.0018 0.0036
-0.0006 0.0035 Ce-144
(+/-)
-0.0016 0.0085
-0.0070 0.0042
-0.0026 0.0045
-0.0096 0.0075
-0.0014 0.0067
-0.0028 0.0054 0.0022 0.0053
-0.0007 0.0049 Be-7 Mn-54 Co-58
(+/-)
(+/-)
(+/-)
0.1060 0.0330
-0.0006 0.0016
-0.0005 0.0022 0.0787 0.0232 0.0012 0.0010
-0.0007 0.001 7 0.0901 0.0268 0.0002 0.0011 0.0012 0.0018 0.1036 0.0339
-0.0005 0.0017 0.0002 0.0027 0.0737 0.0347
-0.0008 0.0017
-0.0014 0.0023 0.0930 0.0322
-0.0004 0.0010
-0.0003 0.0016 0.0894 0.0302
-0.0006 0.0013
-0.0004 0.0019 0.0758 0.0250 0.0002 0.0010
-0.0003 0.0014 Ru-103 Ru-106 Cs-134
(+/-)
(+/-)
(+/-)
0.0014 0.0046 0.0013 0.0158
-0.0005 0.0018
-0.0015 0.0023
-0.0016 0.0101
-0.0017 0.0012
-0.0004 0.0023 0.0048 0.0085 0.0000 0.0010 0.0028 0.0040
-0.0029 0.0127
-0.0006 0.0016
-0.0125 0.0044
-0.0100 0.0145
-0.0003 0.0014
-0.0002 0.0027
-0.0015 0.0089
-0.0001 0.0010
-0.0001 0.0031
-0.0132 0.0128
-0.0006 0.0012 0.0001 0.0026 0.0065 0.0089 0.0009 0.0010 3-11 Annual Radiological Environmental Operating Report 2023 Co-60 Zn-65
(+/-)
(+/-)
-0.0012 0.0018
-0.0010 0.0046 0.0005 0.0009
-0.0012 0.0033 0.0004 0.0010 0.0023 0.0028 0.0003 0.0018 0.0010 0.0024
-0.0009 0.0017 0.0033 0.0037
-0.0004 0.0011
-0.0016 0.0027 0.0004 0.0016
-0.0014 0.0031
-0.0002 0.0012
-0.0009 0.0027 Cs-137 Ba-140
(+/-)
(+/-)
0.0006 0.0016
-0.0028 0.1372
-0.0001 0.0008
-0.0054 0.0812 0.0003 0.0009 0.0079 0.0791
-0.0001 0.0013 0.0092 0.1327 0.0000 0.0013
-0.0224 0.1311
-0.0006 0.0011
-0.0437 0.1100
-0.0002 0.0012 0.0087 0.1431
-0.0003 0.0010
-0.0675 0.0933
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE4 AIR PARTICULATES (pCi/m 3
)
GAMMA SPECTRA - QTR 2 (03/28/23 - 07/05/23)
LOCATION Sr-89
(+/-)
-0.0025 0.0073 2
-0.0012 0.0103 3
-0.0096 0.0079 4
-0.0040 0.0079 10
-0.0001 0.0077 11
-0.0068 0.0072 27 0.0009 0.0085 15C 0.0028 0.0098 LOCATION Nb-95
(+/-)
0.0001 0.0014 2
0.0004 0.0016 3
0.0011 0.0019 4
0.0001 0.0017 10 0.0010 0.0015 11
-0.0014 0.0024 27 0.0017 0.0018 15C 0.0005 0.0020 LOCATION Ce-141
(+/-)
0.0001 0.0027 2
-0.0007 0.0031 3
0.0031 0.0037 4
-0.0011 0.0042 10 0.0003 0.0033 11 0.0015 0.0047 27
-0.0024 0.0044 15C
-0.0046 0.0047 C= Control location, Background location Results in bold type are positi...e.
(+/-)
-0.0010 0.0014 0.0015 0.0025 0.0000 0.0014
-0.0008 0.0014
-0.0010 0.0012
-0.0006 0.0014
-0.0011 0.0010
-0.0001 0.0014 Zr-95
(+/-)
0.0012 0.0025
-0.0004 0.0023 0.0026 0.0035 0.0012 0.0034
-0.0003 0.0031 0.0026 0.0037 0.0012 0.0035 0.0022 0.0037 Ce-144
(+/-)
0.0003 0.0034 0.0025 0.0033 0.0009 0.0044 0.0001 0.0054 0.0030 0.0038
-0.0001 0.0058
-0.0012 0.0054
-0.0001 0.0059 Be-7 Mn-54 Co-58
(+/-)
(+/-)
(+/-)
0.0994 0.0247
-0.0008 0.0008 0.0004 0.0017 0.0951 0.0211 0.0006 0.0009
-0.0015 0.0016 0.0893 0.0195 0.0000 0.0013 0.0003 0.0015 0.0666 0.0208
-0.0005 0.0012
-0.0004 0.0017 0.0930 0.0282
-0.0003 0.0011 0.0005 0.0015 0.1199 0.0317 0.0004 0.0014
-0.0005 0.0019 0.0950 0.0290
-0.0005 0.0010 0.0012 0.0018 0.0985 0.0292
-0.0005 0.0012
-0.0007 0.0018 Ru-103 Ru-106 Cs-134
(+/-)
(+/-)
(+/-)
0.0005 0.0020
-0.0034 0.0069 0.0002 0.0010 0.0000 0.0020
-0.0037 0.0087 0.0000 0.0009
-0.0021 0.0030
-0.0028 0.0108
-0.0003 0.0012
-0.0017 0.0029
-0.0055 0.0106
-0.0002 0.0012 0.0013 0.0023 0.0016 0.0084 0.0008 0.0011 0.0027 0.0033 0.0073 0.0125 0.0006 0.0017 0.0018 0.0029
-0.01 15 0.0105
-0.0004 0.0012
-0.0018 0.0029 0.0057 0.0103
-0.0010 0.0013 3-12 Annual Radiological Environmental Operating Report 2023 Co-60 Zn-65
(+/-)
(+/-)
0.0005 0.0008
-0.0008 0.0027 0.0000 0.0008
-0.0014 0.0021 0.0002 0.0011 0.0019 0.0028
-0.0007 0.0011
-0.0006 0.0029 0.0000 0.0011
-0.0003 0.0024
-0.0001 0.0015 0.0026 0.0030 0.0004 0.0011 0.0010 0.0021 0.0003 0.0011
-0.0008 0.0028 Cs-137 Ba-140
(+/-)
(+/-)
-0.0001 0.0006
-0.0326 0.0872 0.0000 0.0008 0.0360 0.0891
-0.0002 0.0011
-0.0697 0.1 015 0.0003 0.0011 0.0161 0.1052
-0.0003 0.0008
-0.0104 0.0850
-0.0009 0.0014 0.0348 0.1203
-0.0006 0.0011
-0.0104 0.1163 0.0006 0.0010 0.0062 0.1318
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE 4 AIR PARTICULATES (pCi/m 3
)
GAMMA SPECTRA - QTR 3 (07/05/23 - 09/26/23)
LOCATION Sr-89
(+/-)
1 0.0134 0.0138 2
0.0045 0.0143 3
0.0041 0.0156 4
0.0266 0.0195 10 0.0053 0.0127 11 0.0065 0.0126 27 0.0057 0.0138 15C 0.0010 0.0146 LOCATION Nb-95 ---
(+/-)
1
-0.0009 0.0012 2
0.0007 0.0014 3
-0.0005 0.0014 4
-0.0001 0.0012 10
-0.0013 0.0016 11 0.0014 0.0018 27
-0.0003 0.0014 15C 0.0010 0.0013 LOCATION Ce-141
(+/-)
0.0004 0.0019 2
-0.0005 0.0022 3
0.0009 0.0021 4
-0.0011 0.0023 10
-0.0003 0.0031 11
-0.0001 0.0032 27
-0.0011 0.0029 15C 0.0007 0.0019 C= Control location, Background location Results in bold type are positive.
(+/-)
-0.0006 0.0021 0.0015 0.0033
-0.0021 0.0030 0.0015 0.0028
-0.0006 0.0022 0.0018 0.0027 0.0040 0.0032 0.0012 0.0026 Zr-95
(+/-)
-0.0015 0.0017
-0.0005 0.0015 0.0008 0.0026
-0.0011 0.0022 0.0019 0.0027 0.0000 0.0033
-0.0013 0.0026 0.0000 0.0022 Ce-144
(+/-)
0.0005 0.0028 0.0008 0.0032
-0.0017 0.0032
-0.0021 0.0030
-0.0025 0.0038
-0.0005 0.0055
-0.0004 0.0047
-0.0003 0.0029 Be-7 Mn-54 Co-58
(+/-)
(+/-)
(+/-)
0.1072 0.0235 0.0000 0.0008 0.0003 0.0009 0.0965 0.0222 0.0008 0.0010
-0.0002 0.0009 0.1101 0.0269 0.0001 0.0009 0.0002 0.0014 0.0895 0.0279
-0.0007 0.0010
-0.0005 0.0011 0.1191 0.0272 0.0000 0.0010
-0.0001 0.0012 0.0972 0.0399
-0.0007 0.0011 0.0016 0.0019 0.0727 0.0245
-0.0004 0.0013
-0.0013 0.0015 0.1023 0.0235
-0.0001 0.0008
-0.0007 0.0010 Ru-103 Ru-106 Cs-134
(+/-)
(+/-)
(+/-)
0.0004 0.0012
-0.0041 0.0070 0.0000 0.0007 0.0017 0.0015
-0.0037 0.0078 0.0006 0.0009
-0.0005 0.0018
-0.0012 0.0067
-0.0003 0.0006
-0.0001 0.0016
-0.0006 0.0063
-0.0001 0.0010 0.0022 0.0025 0.0005 0.0102
-0.0004 0.0011 0.0011 0.0026
-0.0064 0.0102
-0.0003 0.0009 0.0012 0.0021
-0.0016 0.0084
-0.0009 0.0009 0.0008 0.0016 0.0006 0.0055
-0.0001 0.0008 3-13 Annual Radiological Environmental Operating Report 2023 Co-60 Zn-65
(+/-)
(+/-)
-0.0003 0.0008
-0.0015 0.0022 0.0002 0.0007
-0.0009 0.0015 0.0009 0.001 1
-0.0006 0.0020 0.0002 0.0010
-0.0011 0.0025 0.0004 0.0012
-0.0006 0.0025 0.0005 0.0011 0.0011 0.0028 0.0002 0.0014
-0.0017 0.0020 0.0002 0.0009
-0.0015 0.0020 Cs-137 Ba-140
(+/-)
(+/-)
0.0005 0.0007 0.0677 0.0414 0.0000 0.0006 0.0159 0.0456
-0.0001 0.0009 0.0156 0.0556 0.0004 0.0007
-0.0050 0.0604
-0.0008 0.0010 0.0237 0.0734
-0.0004 0.0011 0.0275 0.0826 0.0007 0.0009
-0.0018 0.0795
-0.0001 0.0006 0.0121 0.0645
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE 4 AIR PARTICULATES (pCi/m 3
)
GAMMA SPECTRA - QTR 4 (09/26/23 - 01/02/24)
LOCATION Sr~9
(+/-)
0.0083 0.0134 2
0.0057 0.0126 3
0.0215 0.0164 4
0.0093 0.0139 10
-0.0022 0.0083 11
-0.0055 0.0095 27
-0.0007 0.0077 15C
-0.0015 0.0086 LOCATION Nb-95
(+/-)
0.0007 0.0013 2
-0.0004 0.0016 3
-0.0013 0.0023 4
0.0006 0.0016 10 0.0008 0.0017 11 0.0005 0.0012 27
-0.0004 0.0014 15C 0.0006 0.0012 LOCATION Ce-141
(+/-)
1
-0.0007 0.0025 2
0.0031 0.0027 3
-0.0017 0.0039 4
-0.0007 0.0029 10 0.0006 0.0040 11
-0.0018 0.0023 27
-0.0001 0.0020 15C
-0.0015 0.0026 C= Control location, Background location Results in bold type are positi1.e.
(+/-)
0.0022 0.0039 0.0023 0.0032 0.0021 0.0028
-0.0001 0.0025 0.0037 0.0031 0.0015 0.0029 0.0006 0.0024
-0.0005 0.0018 Zr-95
(+/-)
0.0002 0.0023 0.0010 0.0029 0.0042 0.0045 0.0002 0.0025 0.0010 0.0030
-0.0015 0.0021 0.0004 0.0026 0.0000 0.0021 Ce-144
(+/-)
-0.0022 0.0035 0.0024 0.0037
-0.0013 0.0053 0.0008 0.0045 0.0027 0.0058 0.0009 0.0035 0.0021 0.0033
-0.0023 0.0038 Be-7 Mn-54 Co-58
(+/-)
(+/-)
(+/-)
0.0718 0.0165 0.0001 0.0011 0.0010 0.0013 0.0591 0.0187
-0.0004 0.0012
-0.0002 0.0015 0.0726 0.0252
-0.0010 0.0015 0.0019 0.0022 0.0668 0.0204 0.0004 0.0009
-0.0001 0.0014 0.0740 0.0181
-0.0012 0.0012
-0.0008 0.0014 0.0675 0.0175
-0.0003 0.0008 0.0003 0.0011 0.0547 0.0217
-0.0002 0.0009
-0.0003 0.0012 0.0548 0.0164
-0.0001 0.0010
-0.0004 0.0012 Ru-103 Ru-106 Cs-134
(+/-)
(+/-)
(+/-)
-0.0005 0.0016 0.0015 0.0075 0.0002 0.0009
-0.0025 0.0021 0.0026 0.0082
-0.0009 0.0012
-0.0013 0.0032
-0.0079 0.0111
-0.0005 0.0013
-0.0004 0.0021 0.0024 0.0091 0.0001 0.0010 0.0015 0.0025 0.0020 0.0097
-0.0002 0.0010
-0.0009 0.0014
-0.0021 0.0070 0.0000 0.0007 0.0005 0.0019
-0.0004 0.0083
-0.0001 0.0008 0.0008 0.0019 0.0027 0.0070
-0.0002 0.0009 3-14 Annual Radiological Environmental Operating Report 2023 Co-60 Zn-65
(+/-)
(+/-)
0.0005 0.0009 0.0011 0.0020
-0.0002 0.0008 0.0000 0.0021 0.0002 0.0015 0.0032 0.0041
-0.0003 0.0010 0.0003 0.0027
-0.0007 0.0011
-0.0001 0.0026
-0.0002 0.0009 0.0011 0.0018 0.0010 0.0009 0.0002 0.0019
-0.0001 0.0009
-0.0006 0.0022 Cs-137 Ba-140
(+/-)
(+/-)
-0.0002 0.0008
-0.0249 0.0483
-0.0003 0.0009 0.0438 0.0623 0.0000 0.0013 0.0568 0.0969 0.0002 0.0009 0.0719 0.0667
-0.0004 0.0011 0.0943 0.0792
-0.0004 0.0008 0.0307 0.0483 0.0003 0.0007 0.0261 0.0595
-0.0006 0.0008
-0.0388 0.0447
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station LOCATION 3
4 14C LOCATION 3
4 14C LOCATION 3
4 14C COLLECTION DATE 05/09/23 05/09/23 05/09/23 COLLECTION DATE 05/09/23 05/09/23 05/09/23 COLLECTION DATE 05/09/23 05/09/23 05/09/23 Be-7
(+/-)
0.189 0.336 0.170 0.494 0.442 0.324 Co-o0
(+/-)
-0.003 0.047
-0.017 0.074 0.008 0.048 Sb-125
(+/-)
-0.092 0.100 0.078 0.144
-0.013 0.113 C= Control location, Background location Results in bold type are positi1.e.
(+/-)
18.330 2.378 11.890 1.880 21.020 2.160 Zn-o5
(+/-)
-0.120 0.131
-0.152 0.154
-0.181 0.112 Cs-134
(+/-)
0.012 0.053 0.072 0.067 0.049 0.049 TABLE 5 SOIL (pCi/g dry wt.)
LOCATIONS Cr-51
(+/-)
-0.312 0.396
-0.259 0.473 0.113 0.326 Nb-95
(+/-)
-0.024 0.064 0.002 0.063
-0.005 0.049 Cs-137
(+/-)
0.099 0.064 0.281 0.140 0.006 0.044 3-15 Mn-54
(+/-)
0.022 0.055
-0.022 0.063 0.021 0.042 Zr-95
(+/-)
-0.029 0.100 0.016 0.095 0.083 0.079 Ce-141
(+/-)
0.043 0.064 0.006 0.077 0.021 0.057 Annual Radiological Environmental Operating Report 2023 Co-58
(+/-)
-0.028 0.050
-0.019 0.056
-0.002 0.043 Ru-103
(+/-)
-0.001 0.048 0.070 0.057
-0.010 0.040 Ce-144
(+/-)
-0.003 0.254
-0.258 0.339 0.019 0.214 Fe-59
(+/-)
-0.114 0.100
-0.116 0.118 0.013 0.109 Ru-106
(+/-)
0.180 0.451
-0.007 0.541 0.069 0.352 Ac-228
(+/-)
0.673 0.280 1.097 0.322 1.400 0.268
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station LOCATION 22 Cow COLLECTION DATE 1-131
(+/-)
Sr-89 Sr-90
(+/-)
(+/-)
TABLE 6 MILK (pCi/1)
(+/-)
Milk was not available for collection in 2023.
Cs-134
(+/-)
Cs-137 Annual Radiological Environmental Operating Report 2023 Ba-140 La-140
(+/-)
(+/-)
(+/-)
Strontium analysis of air samples was performed as a substitute (Table 4) 23 Goat 3-16
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 TABLE 7 WELL WATER (pCi/1)
COLLECTION LOCATION DATE H-3 Be-7 K-40 Cr-51 Mn-54 Co-58 Fe-59 Co-60
~
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
71 02/27/23 209 654 29.3 41.9
-36.6 67.1
-41.1 43.3
-2.98 4.39 2.43 4.47 7.10 9.62 2.56 4.45 06/06/23
-253 581 30.1 31.2
-15.7 42.9
-5.46 33.5 0.85 3.24
-2.05 3.23 1.43 6.00 0.57 3.10 09/07/23 0
724 7.38 26.7 7.11 45.0
-29.6 33.9 0.39 3.10 0.81 3.00
-1.86 6.39
-0.42 3.10 11/27/23
-102 799 2.24 29.7
-25.0 40.9
-14.6 30.7 0.81 3.15
-1.14 3.37
-3.56 4.89
-0.87 3.26 72 02/27/23 209 655
-8.31 34.8 57.3 65.8
-13.8 31.8
-0.94 3.35 1.10 3.38
-0.95 7.80 0.94 2.84 06/05/23 278 619
-13.2 24.3
-31.7 48.2 5.03 32.6 0.24 2.87 0.41 2.77 1.02 6.88 1.34 3.21 09/27/23
-148 716 10.9 20.6 34.4 36.6
-16.2 23.9 1.76 2.25
-1.09 2.34 1.96 4.67 1.99 2.32 12/04/23 38 778
-7.37 32.9
-8.21 67.1
-6.01 38.8 1.40 4.95
-1.24 4.00 4.45 8.84
-1.99 5.87 76 02/21/23 178 631
-18.0 23.7 6.99 41.6
-20.3 22.6
-0.20 2.94
-1.91 2.84 1.04 4.85 3.30 3.09 05/30/23 240 617
-37.8 36.0
-22.5 46.0
-14.4 33.3
-3.41 4.00
-0.12 3.71
-5.13 6.59 1.13 4.78 08/22/23 425 779
-4.80 35.9 16.2 72.5 17.9 33.8
-0.33 4.45
-2.54 3.94
-0.80 7.47 2.40 4.57 11/14/23 108 752 9.63 33.8
-14.9 66.5
-12.7 41.8
-0.33 3.76
-3.08 4.10 4.44 8.17 0.65 4.32 77 02/21/23 127 627
-9.34 25.8
-36.8 41.6
-7.99 26.7
-0.90 2.79
-2.04 2.68
-3.86 5.3 1.55 2.79 05/30/23
-13 600
-4.76 40.8 14.1 73.3
-7.15 47.1 3.45 4.40
-5.77 4.91 1.82 8.52 0.84 5.36 08/22/23 66 755 31.4 44.3
-4.37 71.8
-34.0 54.3
-0.42 5.38
-4.19 4.97
-3.63 10.1
-0.98 5.37 11/14/23 91 745
-9.13 29.9
-12.1 40.8
-30.6 35.8
-2.37 3.25
-4.34 4.04
-0.03 6.74
-1.23 3.34 78 02/21/23 25 620 14.5 35.4 7.19 53.7 27.8 35.1
-0.07 3.92
-0.81 3.40
-2.70 7.53 0.11 4.15 05/30/23 171 613 31.6 33.4
-39.9 62.2 25.4 36.4 0.35 4.38
-4.01 4.09 2.48 7.92 0.46 4.40 08/22/23
-376 740 7.97 39.6
-53.7 59.7 16.2 46.4
-1.50 3.83 2.10 4.72 4.69 8.86 1.46 3.64 11/14/23 355 762 17.5 34.2 22.5 54.5
-11.7 37.4
-0.07 4.10
-0.29 3.98
-0.78 7.79
-1.68 4.00 79 02/27/23
-146 630 11.3 32.9
-39.6 56.4
-1.63 41.3
-1.18 3.38
-0.55 3.65
-0.35 7.52
-3.95 3.30 06/12/23 70 605 16.8 38.1 25.7 67.1
-23.3 47.3
-2.27 4.58
-4.80 4.26 12.5 8.35 5.45 4.67 09/26/23 216 729 18.1 43.0 19.2 63.5
-0.27 42.0
-0.49 4.27
-0.68 3.96
-1.26 8.34 1.63 4.86 11/27/23
-443 776 6.57 30.7
-12.9 51.8 9.03 34.7 2.03 4.20
-1.66 3.84
-4.28 7.24
-0.67 4.30 81 02/27/23 476 672
-7.84 38.1 10.42 57.2 38.2 38.3
-2.23 4.66 0.79 3.72
-5.12 8.13
-1.30 4.25 06/06/23 392 626
-3.76 26.6
-9.35 39.2
-23.1 33.8 0.64 2.92
-0.59 2.99 4.38 5.20 1.86 2.95 09/06/23 409 749
-1.15 25.7 21.1 40.7
-14.2 30.2 1.80 2.75
-1.50 2.85
-0.61 5.91
-1.42 3.26 10/17/23 112 754 1.88 38.0 3.24 66.8 11.3 38.1
-2.25 4.36 0.81 4.47 4.26 8.31
-0.18 4.44 82 01/26/23 400 600
-19.1 30.3 15.2 41.1
-37.7 38.5
-0.97 3.44
-2.70 3.68 1.21 6.87
-0.76 3.78 05/17/23
-19 619
-13.6 32.4 26.3 45.0
-18.3 39.1
-1.65 3.83
-4.15 4.08 7.66 6.98
-0.47 3.79 07/18/23
-113 513
-4.59 13.0 0.82 30.0
-8.56 14.6
-2.19 1.51
-1.95 1.55
-1.11 3.26 0.09 1.81 10/16/23
-116 736
-6.15 30.9
-3.12 49.5
-34.2 33.6
-2.24 3.70
-0.03 3.71
-1.51 7.36 1.27 3.64 83 03/21/23
-57 611 17.8 32.1 0.32 42.8
-0.21 36.1 0.27 4.10
-2.61 3.99
-4.24 5.30 1.10 3.99 05/25/23
-354 611
-1.17 10.3 6.67 21.3 0.71 12.8 0.14 1.01 0.11 1.13 3.71 2.46 0.81 1.05 09/05/23 43 736 13.3 21.6 16.2 31.9 10.8 30.3 0.31 2.63
-0.52 2.18
-0.54 5.42
-0.35 2.69 10/18/23 11 740 6.10 38.9 70.3 74.6 4.67 41.9
-2.36 4.14
-1.00 4.11 0.30 7.59 2.13 3.92 3-17
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station LOCATION 71 72 76 77 78 79 81 82 83 COLLECTION DATE 02/27/23 06/06/23 09/07/23 11/27/23 02/27/23 06/05/23 09/27/23 12/04/23 02/21 /23 05/30/23 08/22/23 11/14/23 02/21/23 05/30/23 08/22/23 11/14/23 02/21 /23 05/30/23 08/22/23 11/14/23 02/27/23 06/12/23 09/26/23 11/27/23 02/27/23 06/06/23 09/06/23 10/17/23 01/26/23 05/17/23 07/18/23 10/16/23 03/21/23 05/25/23 09/05/23 10/18/23 Zn-65
(+/-)
4.63 9.27
-7.48 6.47
-14.0 7.77
-0.68 7.16
-3.58 8.03
-7.78 6.85
-7.51 5.49
-22.7 14.0 3.05 7.53
-8.87 8.54
-20.6 12.9
-8.43 11.3
-1.78 6.40
-0.25 11.1
-40.8 16.1 6.64 6.98
-4.41 8.15
-2.42 7.59
-10.1 11.0
-10.5 10.6
-21.5 9.60
-6.45 10.8 3.73 9.51
-5.53 11.1
-3.89 9.29
-14.2 7.22 1.48 5.66 5.05 9.22 1.71 7.40
-0.56 8.00
-0.92 3.76 4.93 7.75
-23.6 10.6
-4.10 2.22
-1.49 5.06 14.6 10.8 Nb-95
(+/-)
0.56 4.29
-0.99 3.16 3.31 3.44
-1.48 3.97
-2.22 5.22 0.66 2.77 3.47 2.42
-3.49 4.49 0.10 3.51
-2.67 4.19
-5.41 5.15
-4.01 4.47 2.12 3.12
-11.4 5.56 6.24 5.62
-2.77 5.15
-3.56 4.08
-4.89 4.36 1.53 5.25 3.07 4.31 0.84 4.15 3.66 4.39
-0.73 4.48 8.08 4.37 3.72 4.32 0.07 2.99 1.92 3.07
-7.01 5.36 7.35 4.52 6.65 4.83 4.10 1.82 4.27 3.72 0.82 4.62 1.14 1.16 2.40 2.62 7.30 4.65 TABLE 7 WELL WATER (pCi/1)
Zr-95
(+/-)
3.79 6.26
-3.87 5.57
-2.13 5.43
-2.00 5.21
-4.73 5.86
-1.50 5.93
-2.82 4.05
-1.72 7.59 1.34 4.88 0.02 6.73
-4.74 6.78
-5.13 6.32 1.28 4.30 0.94 8.31 1.25 8.55 0.41 6.12
-1.69 5.91 0.49 7.73
-0.86 8.26 4.95 7.08
-3.25 6.93
-0.01 7.73 3.13 7.73
-1.50 5.56 3.42 7.83 0.28 4.90 1.19 5.30
-5.59 6.94
-3.53 6.17
-1.23 6.70 0.54 2.52
-3.29 6.76 0.11 6.29
-0.76 1.95
-3.69 3.90
-0.66 7.32 Ru-103
(+/-)
-3.21 5.13
-3.37 3.66
-0.70 3.71 1.27 3.65
-3.73 3.69
-3.37 3.21 1.06 2.54
-0.38 4.88
-1.06 3.08
-0.29 4.47
-4.77 4.28 2.24 4.11 0.83 3.08
-0.11 4.87
-2.26 5.51 0.18 3.98
-4.45 3.53 1.58 3.73
-4.26 5.44
-1.16 4.27 1.06 4.55
-0.02 5.09 1.50 4.74
-0.04 4.11
-0.40 4.27 1.46 3.37
-3.34 3.33
-1.30 4.66
-0.63 4.17
-0.40 4.04
-2.44 1.69
-0.62 4.08
-1.81 4.41
-1.81 1.39
-0.92 2.85
-0.71 4.89 3-18 Ru-106
(+/-)
-2.26 38.6 12.2 27.3
-8.28 26.9 7.67 31.1 5.86 32.8 10.8 22.3
-0.05 21.8 37.0 42.2 2.34 24.6
-21.0 36.8 5.61 35.3
-5.61 36.5
-16.3 24.7 19.2 37.1 33.9 47.2
-10.8 31.7
-23.6 28.8 6.59 33.8 2.80 39.0
-25.0 35.4 5.77 30.6
-25.7 34.9 18.9 40.1 8.57 33.7 20.3 42.1
-7.12 24.5 1.15 24.0
-18.0 40.7
-14.1 30.1
-2.17 30.4 2.37 13.4 10.4 27.7
-12.6 31.7 1.27 9.24
-3.38 22.2
-10.2 37.4 Annual Radiological Environmental Operating Report 2023 Sb-125
(+/-)
-5.75 12.4
-3.34 9.23 3.58 9.15 6.69 8.88
-0.04 9.67
-2.45 7.39 2.18 6.90
-7.45 12.4 2.24 8.0 6.75 11.1 5.47 11.3
-6.59 9.47 0.27 8.37
-8.84 13.5
-10.2 14.2 12.7 10.6
-6.76 10.0 0.24 10.1 1.97 13.8 7.96 10.4 2.15 11.4
-6.45 13.0 3.37 13.2 4.68 10.7 4.44 12.2 0.40 7.76 0.37 7.87
-6.90 12.1 2.63 9.65
-1.62 11.8
-1.03 4.26 8.44 9.81 4.70 9.92
-1.11 2.90
-1.79 7.16 1.61 12.8 1-131
(+/-)
5.41 8.09
-5.11 9.43
-1.75 8.90
-1.71 5.40
-0.59 5.08
-4.57 9.06 2.81 3.83 0.46 5.68
-0.56 3.46
-1.33 7.00 0.17 6.37
-2.09 6.08 1.99 3.90 1.96 8.23
-0.78 8.97
-1.61 6.55
-2.84 5.92
-4.69 5.83
-0.91 7.70 0.09 6.32 2.09 7.65
-0.61 8.61 6.40 7.41
-2.24 7.01 0.92 7.54
-7.28 9.42 5.99 8.20 2.82 7.09 2.99 8.62
-3.23 8.14
-0.08 3.32 2.68 6.84
-2.77 8.69 3.60 4.80 2.94 7.49 3.61 6.93 Cs-134
(+/-)
2.02 4.52 0.04 3.57
-0.36 3.21 2.96 3.45
-1.60 4.19 0.70 2.83
-1.15 2.48 0.02 4.51
-3.52 3.27
-3.51 4.09 3.03 4.58 0.06 3.86 0.29 3.01 3.87 5.21
-1.18 5.78
-1.33 3.61
-0.55 3.60 1.04 3.80 3.42 4.58 0.67 3.71
-0.42 3.95
-2.11 5.36
-3.12 4.02
-2.54 4.00 1.91 4.94 2.68 3.19 0.94 3.01
-0.05 3.88 1.09 3.27 2.55 3.95 0.72 1.59 1.39 4.01
-0.29 3.66 0.05 1.13 1.33 2.26 1.03 4.92
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 TABLE 7 WELL WATER (pCi/1)
COLLECTION LOCATION DATE Cs-137 Ba-140 La-140 Ac-228
~
(+/-)
(+/-)
(+/-)
71 02/27/23
-1.71 4.84
-18.7 21.4 1.47 6.95
-1.50 14.5 06/06/23 2.45 3.33 1.50 20.2
-4.02 6.65
-1.31 11.5 09/07/23
-2.94 3.19
-13.5 20.2
-3.75 6.82 0.38 10.7 11/27/23
-1.63 3.38 5.24 14.5 2.72 5.90 6.12 12.1 72 02/27/23
-1.53 4.07 9.23 16.1
-0.04 6.58 1.99 15.2 06/05/23 0.75 2.58
-4.91 20.6 1.92 8.55 1.64 10.3 09/27/23
-0.64 2.54
-6.87 10.4
-1.01 3.34
-1.26 9.4 12/04/23
-2.71 5.22
-8.97 18.6 0.37 6.02
-3.23 18.9 76 02/21/23
-3.54 3.23 1.33 11.4 3.96 4.04
-2.56 12.5 05/30/23
-0.77 3.88
-6.56 18.5
-0.51 5.05
-2.05 14.8 08/22/23
-2.61 4.02 7.53 20.4
-3.23 6.54
-4.06 15.2 11/14/23 2.15 3.97 9.93 20.8 3.25 7.90
-1.83 17.6 77 02/21 /23
-3.85 3.00
-11.4 12.2 2.69 3.32 0.47 11.0 05/30/23
-0.49 5.39
-4.96 21.6
-2.57 8.12 0.32 15.7 08/22/23
-6.60 5.04 0.00 21.9
-0.36 7.51 11.5 17.7 11/14/23
-3.21 4.01 12.8 17.6 0.14 5.90 3.51 14.9 78 02/21 /23 0.02 3.76 2.65 16.0 3.11 6.16
-9.09 13.0 05/30/23
-1.26 3.39 2.67 16.2 7.88 6.39
-4.09 15.3 08/22/23
-2.92 5.26 9.29 23.7 3.12 6.33 5.58 19.8 11/14/23 0.53 4.70 7.43 18.6 1.30 6.00
-8.83 14.3 79 02/27/23 0.33 3.92 13.48 19.3
-1.67 6.32
-4.49 14.0 06/12/23
-2.65 4.77 14.58 22.7
-1.11 7.51
-2.28 17.0 09/26/23 1.68 4.67 11.74 19.2
-2.65 7.80 9.60 16.9 11/27/23
-1.82 4.02
-8.33 17.0
-0.74 5.68
-3.16 15.4 81 02/27/23
-4.83 4.54 6.85 20.0 3.02 5.78
-13.7 15.1 06/06/23
-0.04 2.97
-6.77 17.8 1.01 5.92 3.86 10.8 09/06/23 1.19 2.88 12.83 18.0 2.01 6.59 8.55 10.9 10/17/23
-6.56 5.87
-6.43 22.4 2.28 7.16 1.33 17.4 82 01 /26/23
-2.46 3.81 2.10 20.9 6.38 6.32
-7.12 13.1 05/17/23
-5.14 3.98 16.2 20.1
-0.56 5.17 3.67 13.7 07/18/23 1.21 1.78 2.24 8.95 1.28 3.18 2.03 6.59 10/16/23
-0.07 3.82
-19.0 16.9
-2.68 6.48
-11.7 13.7 83 03/21 /23 1.55 3.80 2.55 19.6
-1.29 6.87
-2.18 13.5 05/25/23 0.19 1.06 4.30 9.09 2.31 3.00 2.94 4.32 09/05/23 0.17 2.20
-12.6 17.6 1.23 5.10 8.19 8.47 10/18/23
-3.34 4.91
-15.7 18.7 0.52 5.29
-7.87 16.9 3-19
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE 8 FRUITS & VEGETABLES (pCi/g wet wt.)
Annual Radiological Environmental Operating Report 2023 LOCATION 25 (fruit are extra sam pies not required by the REMODCM)
COLLECTION DATE
______!re_e Be-7 K-40 Cr-51 Mn-54 Co-58 Fe-59 Co-60
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
07/11/23 Lettuce 0.381 0.146 3.133 0.437
-0.013 0.078
-0.006 0.010
-0.003 0.009
-0.005 0.022
-0.002 0.011 07/11/23 Apples
-0.018 0.084 1.099 0.335
-0.015 0.090 0.003 0.013 0.000 0.013 0.003 0.021
-0.002 0.011 09/19/23 Tomatoes 0.041 0.099 2.023 0.402 0.042 0.092 0.007 0.011 0.002 0.012
-0.016 0.028 0.002 0.011 09/19/23 Apples 0.123 0.097 1.038 0.268 0.052 0.093 0.002 0.011
-0.009 0.011 0.003 0.021
-0.008 0.011 COLLECTION DATE
______!re_e Zn-65 Nb-95 Zr-95 Ru-103 Ru-106 Sb-125 1-131
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
07/11/23 Lettuce
-0.007 0.030
-0.006 0.011
-0.013 0.016
-0.003 0.009
-0.048 0.077 0.002 0.026
-0.010 0.010 07/11/23 Apples
-0.025 0.029 0.000 0.012
-0.005 0.019 0.004 0.011
-0.049 0.113 0.016 0.033
-0.005 0.012 09/19/23 Tomatoes
-0.032 0.028 0.003 0.009
-0.004 0.020 0.006 0.010
-0.040 0.090 0.015 0.027 0.001 0.013 09/19/23 Apples 0.002 0.023 0.003 0.011 0.003 0.019
-0.001 0.010
-0.017 0.088 0.002 0.025
-0.004 0.016 COLLECTION DATE
____!rpe Cs-134 Cs-137 Ba-140 La-140 Ce-141 Ce-144 Ac-228
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
07/11/23 Lettuce 0.003 0.012
-0.008 0.010
-0.016 0.037 0.006 0.012 0.008 0.013 0.029 0.057
-0.014 0.039 07/11/23 Apples
-0.001 0.013 0.003 0.013
-0.002 0.039
-0.003 0.012
-0.001 0.014
-0.020 0.058 0.012 0.037 09/19/23 Tomatoes
-0.012 0.013
-0.003 0.013
-0.009 0.049
-0.004 0.016
-0.015 0.015
-0.060 0.064
-0.004 0.041 09/19/23 Apples 0.002 0.011
-0.002 0.010
-0.017 0.044
-0.010 0.015
-0.002 0.014 0.021 0.056 0.006 0.038 Results in bold type are positi1.e.
3-20
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE 8 FRUITS & VEG ET ABLES (pCi/g wet wt.)
Annual Radiological Environmental Operating Report 2023 LOCATION 25X (fruit are extra samples not required by the REMODCM)
COLLECTION DATE Type Be-7 K-40 Cr-51 Mn-54 Co-58 Fe-59 Co-60
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
08/29/23 Tomatoes
-0.023 0.077 1.837 0.304 0.080 0.074 0.000 0.009 0.002 0.008
-0.011 0.016 0.004 0.010 09/19/23 Tomatoes 0.045 0.071 1.847 0.364 0.040 0.074
-0.008 0.009
-0.002 0.012
-0.012 0.021
-0.004 0.012 COLLECTION DATE T~
Zn-65 Nb-95 Zr-95 Ru-103 Ru-106 Sb-125 1-131
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
08/29/23 Tomatoes 0.012 0.021
-0.005 0.008 0.006 0.016
-0.011 0.008
-0.011 0.091 0.011 0.022 0.000 0.011 09/19/23 Tomatoes
-0.016 0.022 0.003 0.010
-0.001 0.017
-0.008 0.009 0.007 0.089 0.021 0.022 0.004 0.014 COLLECTION DATE T~
Cs-134 Cs-137 Ba-140 La-140 Ce-141 Ce-144 Ac-228
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
08/29/23 Tomatoes 0.002 0.011 0.007 0.009 0.011 0.026 0.003 0.012 0.000 0.014 0.052 0.059 0.011 0.030 09/19/23 Tomatoes 0.003 0.010 0.002 0.010
-0.025 0.036 0.003 0.014 0.001 0.013
-0.008 0.051
-0.025 0.038 Results in bold type are positi-..e.
3-21
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station TABLE 8 FRUITS & VEGETABLES (pCi/g wet wt.)
Annual Radiological Environmental Operating Report 2023 LOCATION 26C (fruit are extra samples not required by the REMODCM)
COLLECTION DATE T~
Be-7
(+/-)
07/11/23 Lettuce 0.328 0.136 07/11/23 Plums
-0.008 0.072 08/29/23 Tomatoes 0.053 0.103 09/19/23 Tomatoes 0.026 0.072 09/19/23 Apples 0.076 0.065 COLLECTION DATE Type Zn-65
(+/-)
07/11/23 Lettuce
-0.021 0.034 07/11/23 Plums
-0.015 0.024 08/29/23 Tomatoes 0.003 0.030 09/19/23 Tomatoes
-0.004 0.022 09/19/23 Apples
-0.007 0.018 COLLECTION DATE Type Cs-134
(+/-)
07/11/23 Lettuce 0.013 0.015 07/11/23 Plums 0.005 0.009 08/29/23 Tomatoes
-0.009 0.015 09/19/23 Tomatoes
-0.006 0.010 09/19/23 Apples 0.001 0.009 C = Control location, Background location Results in bold type are posifr,e.
K-40 Cr-51
(+/-)
(+/-)
2.792 0.460
-0.002 0.095 1.508 0.279
-0.028 0.066 1.959 0.439
-0.105 0.110 1.826 0.268 0.010 0.083 0.832 0.276
-0.047 0.074 Nb-95 Zr-95
(+/-)
(+/-)
-0.007 0.013
-0.004 0.022 0.002 0.009 0.002 0.016 0.007 0.012 0.001 0.019
-0.002 0.009
-0.017 0.013
-0.001 0.009
-0.016 0.018 Cs-137 Ba-140
(+/-)
(+/-)
0.003 0.014
-0.034 0.042
-0.001 0.009 0.005 0.033
-0.005 0.014
-0.013 0.046
-0.008 0.010
-0.060 0.043
-0.001 0.009
-0.008 0.037 3-22 Mn-54 Co-58 Fe-59 Co-60
(+/-)
(+/-)
(+/-)
(+/-)
0.007 0.013 0.001 0.009 0.009 0.029
-0.006 0.014 0.003 0.009 0.002 0.008
-0.006 0.018 0.003 0.007
-0.004 0.009
-0.005 0.012
-0.010 0.027 0.001 0.011 0.006 0.008
-0.005 0.009
-0.009 0.017 0.001 0.011 0.000 0.008 0.003 0.010 0.005 0.020
-0.005 0.009 Ru-103 Ru-106 Sb-125 1-131
(+/-)
(+/-)
(+/-)
(+/-)
-0.007 0.013 0.147 0.112
-0.013 0.036 0.010 0.013
-0.003 0.008
-0.006 0.080
-0.008 0.023
-0.002 0.009
-0.012 0.013 0.025 0.125
-0.028 0.038
-0.003 0.014
-0.001 0.008
-0.012 0.078
-0.014 0.024
-0.014 0.014 0.002 0.009 0.035 0.080 0.018 0.025 0.008 0.011 La-140 Ce-141 Ce-144 Ac-228
(+/-)
(+/-)
(+/-)
(+/-)
-0.002 0.008 0.001 0.017
-0.035 0.073 0.001 0.054
-0.005 0.010
-0.001 0.011 0.030 0.047
-0.017 0.032 0.007 0.016 0.004 0.021 0.031 0.078 0.004 0.044
-0.004 0.014
-0.004 0.014
-0.015 0.054 0.005 0.029 0.001 0.017 0.002 0.012
-0.007 0.055
-0.021 0.036
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION DATE 05/23/23 09/19/23 05/23/23 09/19/23 05/23/23 09/19/23 COLLECTION DATE 05/23/23 09/19/23 05/23/23 09/19/23 05/23/23 09/19/23 Be-7
(+/-)
0.520 0.232 2.823 0.392 Zn-65
(+/-)
-0.063 0.053
-0.017 0.040 Cs-134
(+/-)
-0.005 0.017 0.012 0.019 Be-7
(+/-)
0.169 0.121 2.820 0.321 Zn-65
(+/-)
0.006 0.033
-0.016 0.031 Cs-134
(+/-)
-0.009 0.014 0.003 0.015 Results in bold type are positi-..e.
(+/-)
3.682 0.601 2.803 0.517 Nb-95
(+/-)
-0.011 0.016
-0.004 0.016 Cs-137
(+/-)
-0.006 0.015
-0.002 0.015 K-40
(+/-)
2.605 0.569 2.318 0.443 Nb-95
(+/-)
-0.001 0.013 0.004 0.013 Cs-137
(+/-)
-0.001 0.014 0.000 0.013 TABLE 9 BROADLEAF VEGETATION (pCi/g wet wt.)
LOCATION 1 Cr-51
(+/-)
0.018 0.131
-0.101 0.139 Zr-95
(+/-)
-0.009 0.027
-0.005 0.030 Ba-140
(+/-)
-0.004 0.065 0.019 0.046 Mn-54
(+/-)
-0.002 0.015
-0.006 0.017 Ru-103
(+/-)
-0.011 0.014
-0.006 0.016 La-140
(+/-)
0.015 0.019
-0. 031
- 0. 028 LOCATION 10 Cr-51 Mn-54
(+/-)
(+/-)
-0.028 0.120 0.005 0.014
-0.080 0.120 0.004 0.012 Zr-95 Ru-103
(+/-)
(+/-)
0.003 0.021
-0.002 0.015 0.002 0.022 0.000 0.011 Ba-140 La-140
(+/-)
(+/-)
0.036 0.054 0.010 0.016
-0.020 0.050 0.005 0.014 3-23 Co-58
(+/-)
0.005 0.015
-0.001 0.015 Ru-106
(+/-)
0.081 0.136
-0.002 0.138 Ce-141
(+/-)
-0.001 0.021
-0.036 0.025 Co-58
(+/-)
-0.008 0.016
-0.004 0.011 Ru-106
(+/-)
0.012 0.151
-0.054 0.104 Ce-141
(+/-)
-0.005 0.022
-0.020 0.023 Annual Radiological Environmental Operating Report 2023 Fe-59
(+/-)
0.009 0.032 0.019 0.038 Sb-125
(+/-)
-0.001 0.041
-0.055 0.046 Ce-144
(+/-)
0.024 0.096 0.086 0.096 Fe-59
(+/-)
0.022 0.029
-0.001 0.024 Sb-125
(+/-)
-0.022 0.041 0.024 0.030 Ce-144
(+/-)
0.048 0.085
-0.026 0.089 Co-60
(+/-)
-0.007 0.019 0.001 0.018 1-131
(+/-)
0.009 0.018
-0.016 0.027 Ac-228
(+/-)
0.053 0.061 0.051 0.063 Co-60
(+/-)
-0.006 0.017 0.008 0.016 1-131
(+/-)
-0.015 0.015 0.002 0.019 Ac-228
(+/-)
0.061 0.063 0.154 0.059
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION DATE 05/23/23 09/19/23 05/23/23 09/19/23 05/23/23 09/19/23 COLLECTION DATE 05/23/23 09/19/23 05/23/23 09/19/23 05/23/23 09/19/23 Be-7
(+/-)
0.092 0.157 0.925 0.301 Zn-65
(+/-)
-0.034 0.035
-0.051 0.042 Cs-134
(+/-)
0.015 0.017 0.007 0.020 Be-7
(+/-)
0.406 0.241 2.247 0.367 Zn-65
(+/-)
-0.023 0.052
-0.029 0.040 Cs-134
(+/-)
0.005 0.019 0.012 0.019 C= Control location, Background location Results in bold type are positil.e.
(+/-)
2.515 0.532 1.971 0.499 Nb-95
(+/-)
-0.017 0.018
-0.014 0.015 Cs-137
(+/-)
0.005 0.016 0.007 0.020 K-40
(+/-)
3.713 0.689 3.115 0.547 Nb-95
(+/-)
0.014 0.019 0.002 0.016 Cs-137
(+/-)
0.006 0.017 0.011 0.018 TABLE 9 BROADLEAF VEGETATION (pCi/g wet wt.)
LOCATION 17 Cr-51 Mn-54
(+/-)
(+/-)
-0.005 0.122 0.006 0.014
-0.014 0.140
-0.014 0.018 Zr-95 Ru-103
(+/-)
(+/-)
0.003 0.026
-0.003 0.016
-0.011 0.031
-0.004 0.017 Ba-140 La-140
(+/-)
(+/-)
-0.024 0.057
-0.021 0.019 0.101 0.081
-0.001 0.026 LOCATION 26C Cr-51 Mn-54
(+/-)
(+/-)
0.002 0.124
-0.006 0.017
-0.100 0.146 0.001 0.017 Zr-95 Ru-103
(+/-)
(+/-)
-0.007 0.022
-0.008 0.017 0.016 0.027 0.028 0.017 Ba-140 La-140
(+/-)
(+/-)
-0.025 0.062
-0.014 0.024
-0.010 0.071
-0.001 0.020 3-24 Co-58
(+/-)
-0.010 0.016
-0.021 0.019 Ru-106
(+/-)
-0.020 0.142
-0.152 0.185 Ce-141
(+/-)
-0.013 0.025
-0.001 0.028 Co-58
(+/-)
-0.001 0.016 0.015 0.015 Ru-106
(+/-)
-0.096 0.151 0.115 0.146 Ce-141
(+/-)
0.000 0.021 0.009 0.025 Annual Radiological Environmental Operating Report 2023 Fe-59 Co-60
(+/-)
(+/-)
-0.006 0.024
-0.005 0.018
-0.058 0.040 0.003 0.017 Sb-125 1-131
(+/-)
(+/-)
0.001 0.046
-0.015 0.019
-0.025 0.045
-0.028 0.025 Ce-144 Ac-228
(+/-)
(+/-)
-0.010 0.107 0.037 0.056
-0.007 0.109 0.053 0.077 Fe-59 Co-60
(+/-)
(+/-)
-0.010 0.035
-0.006 0.019
-0.002 0.037 0.001 0.011 Sb-125 1-131
(+/-)
(+/-)
-0.005 0.042
-0.010 0.021 0.003 0.045
-0.003 0.026 Ce-144 Ac-228
(+/-)
(+/-)
-0.043 0.091 0.054 0.067
-0.028 0.094 0.128 0.085
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 TABLE 10 SEAWATER (pCi/1)
LOCATION 32 COLLECTION DATE H-3 Be-7 K-40 Cr-51 Mn-54 Co-58 Fe-59
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
01/31/23 1030 253
-11.2 35.1 304 91
-18.8 44.8
-1.40 3.52 1.08 4.16 3.16 8.27 02/27/23 1040 244 17.4 31.7 322 75
-17.2 32.1 0.99 2.75
-2.76 3.36 4.79 6.83 03/28/23 1060 263
-3.95 33.9 267 81 11.2 38.4 1.72 3.93
-3.46 4.01 4.74 8.73 04/25/23 1420 339 19.1 31.1 317 78 4.17 32.8 2.07 3.85 2.39 3.18 1.86 7.14 05/30/23 788 411
-4.14 32.2 164 97
-31.8 31.6 0.97 3.64
-0.43 3.72 0.62 9.00 06/27/23 628 219
-13.5 38.3 230 98
-6.96 39.0 1.72 3.66
-4.27 4.12 5.60 7.21 07/25/23 266 129 0.20 5.46 330 32
-0.64 5.04 0.34 0.65
-0.51 0.54
-0.42 1.25 08/29/23 85 188
-11.7 24.6 321 76 7.80 24.7 1.62 3.14 0.50 3.08 2.57 5.79 09/26/23 775 221
-0.46 31.9 348 91 12.4 29.8
-1.93 3.70 3.14 3.81 5.53 7.54 10/31/23 1560 273
-13.2 41.2 411 100
-37.3 36.6 1.90 4.12
-3.03 4.47 4.99 9.13 11/28/23 562 232 45.7 41.1 302 117 23.7 32.9 2.25 3.69 0.84 4.48
-0.75 7.39 12/27/23 537 214 2.93 38.5 322 130
-1.75 38.2
-0.10 3.83
-5.16 4.72 4.42 9.61 COLLECTION DATE Co-60 Zn-65 Nb-95 Zr-95 Ru-103 Ru-106 Sb-125
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
(+/-)
01/31/23 2.07 3.91
-7.33 10.3
-1.52 4.32
-3.62 6.95 0.65 4.74 14.4 42.4 2.37 11.8 02/27/23 1.33 3.03
-1.68 7.01
-0.81 3.40 0.22 6.00
-1.36 3.48 11.5 28.9
-9.17 10.3 03/28/23 3.62 4.24
-3.76 8.99 3.79 3.64
-7.29 6.35 1.63 4.20
-4.60 40.5
-4.16 11.9 04/25/23 2.81 3.46 3.37 7.24 0.14 3.74
-3.03 6.33
-1.08 3.32 20.5 29.2 1.27 10.2 05/30/23
-0.19 3.84 6.90 10.2
-1.28 4.01 0.90 7.73
-3.64 4.20 6.64 33.9 7.29 9.75 06/27/23
-0.14 4.72
-5.51 9.68 2.03 3.70 0.35 5.82
-1.69 4.41 3.75 40.5
-5.22 12.3 07/25/23 1.32 0.96
-1.11 1.42 0.02 0.59
-0.03 1.01 0.88 0.61 1.98 6.14 0.99 1.79 08/29/23 0.62 3.14
-1.35 7.56
-0.39 2.99
-2.94 5.82
-0.41 3.20 9.89 27.8
-4.97 8.11 09/26/23 0.14 3.91 0.53 8.51
-0.56 3.79
-0.40 6.43 2.00 3.73 35.7 32.8 1.12 9.99 10/31/23
-1.44 5.17
-22.7 11.9 4.63 5.20 2.56 8.46
-0.18 4.42
-2.95 38.6 2.89 12.4 11/28/23
-1.58 4.10
-9.61 10.2 1.89 4.56 2.19 7.64 1.70 4.21 15.3 34.4 1.36 12.6 12/27/23
-2.53 3.93
-12.2 10.2 3.61 4.87
-0.48 7.44
-0.84 4.85 1.71 44.9
-14.2 13.0 Results in bold type are positi1.e.
3-25
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION DATE 1-131
(+/-)
01/31 /23 7.74 7.01 02/27/23
-0.81 5.81 03/28/23
-1.39 5.73 04/25/23 2.43 6.30 05/30/23 1.05 5.96 06/27/23 2.80 5.75 07/25/23
-1.92 1.22 08/29/23
-1.53 3.67 09/26/23
-0.54 5.46 10/31/23 1.63 7.30 11/28/23 4.68 6.93 12/27/23 0.25 5.31 COLLECTION DATE H-3 ~
03/21 /23 52 174 06/20/23
-36 176 09/12/23 106 103 12/20/23
-217 180 COLLECTION DATE Co-60 ~
03/21/23 1.06 3.74 06/20/23 2.20 3.60 09/12/23 1.83 2.91 12/20/23
-0.75 4.06 COLLECTION DATE 1-131 F+l" 03/21 /23 0.96 6.35 06/20/23
-2.26 6.30 09/12/23
-0.57 5.00 12/20/23 0.16 7.43 C= Control location, Background location Results in bold type are positi1.e.
Cs-134
(+/-)
3.69 4.85
-0.28 3.74
-2.03 4.86
-0.64 3.71
-1.91 4.08
-3.36 4.62
-0.15 0.62 1.86 3.85
-0.27 3.63 3.78 4.91 5.11 4.84
-2.57 5.07 Be-7
(+/-)
-5.61 30.8 17.8 28.8 19.7 31.0
-23.1 36.1 Zn-65
(+/-)
3.44 7.44 0.79 6.75
-7.07 7.92
-8.41 8.29 Cs-134
(+/-)
-0.67 3.96
-0.50 4.03 0.72 3.40 2.46 4.05 TABLE10 SEAWATER (pCi/1)
LOCATION 32 Cont'd Cs-137 Ba-140
(+/-)
(+/-)
-2.45 4.38 2.79 19.6
-1.12 3.49 2.79 14.7
-0.49 4.49
-5.72 15.0 0.70 3.82 3.51 15.1 2.12 4.07
-0.43 16.7 1.75 4.24 11.8 16.2 0.71 0.69 1.95 2.74 "
-1.49 3.11
-1.14 11.7 1.57 3.56
-3.76 17.4
-0.22 4.08
-6.34 17.7 6.93 4.23 11.3 19.5 1.31 4.59
-3.42 17.0 LOCATION 37C K-40 Cr-51
(+/-)
(+/-)
286 98
-1.87 36.0 257 84 3.56 29.9 308 82
-27.3 31.8 216 87 28.7 32.6 Nb-95 Zr-95
(+/-)
(+/-)
-0.37 3.25 2.88 5.67 0.55 3.71
-5.67 6.12
-1.78 2.96
-1.04 6.16 2.48 3.86 3.53 5.97 Cs-137 Ba-140
(+/-)
(+/-)
1.84 3.63
-15.8 16.3 0.36 3.42 8.57 14.5
-1.40 3.61 14.0 16.6
-1.26 4.19
-6.07 18.3 3-26 La-140
(+/-)
-2.64 6.23 2.34 5.79
-2.70 4.26 1.00 5.46 1.67 5.17
-2.88 4.65
-0.23 0.85
-1.72 3.73 2.71 4.94
-6.62 7.18
-0.75 8.29
-1.92 5.46 Mn-54
(+/-)
0.44 3.34 0.78 3.39
-0.58 3.42 1.70 3.67 Ru-103
(+/-)
0.17 3.93
-0.73 3.49
-1.43 3.93
-3.94 4.31 La-140
(+/-)
6.85 5.10
-0.22 6.36 1.48 4.82 0.83 6.48 Annual Radiological Environmental Operating Report 2023 Ac-228
(+/-)
2.56 17.5 7.91 12.6 2.10 15.1
-1.65 12.4
-7.23 14.0
-10.8 17.4 2.80 2.46
-14.7 12.7
-1.93 14.0
-2.43 16.3
-0.79 16.2
-8.11 16.5 Co-58 Fe-59
(+/-)
(+/-)
-2.38 3.19 3.20 7.73
-0.09 3.33 5.06 6.78
-0.56 3.18
-1.23 7.80
-0.57 3.61
-0.85 8.28 Ru-106 Sb-125
(+/-)
(+/-)
-11.1 34.0
-1.66 9.41
-22.6 33.3
-0.32 9.21
-19.8 39.0 9.37 8.71 25.1 36.7
-3.46 11.5 Ac-228
(+/-)
-5.49 13.4 12.1 12.3
-5.91 13.6 2.30 13.3
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION LOCATION DATE Be-7
(+/-)
31 06/26/23 0.479 0.437 31 11/07/23
-0.120 0.394 32 06/12/23 0.446 0.423 32 12/14/23 0.718 0.502 33 06/26/23
-0.130 0.255 33 12/07/23 0.038 0.338 34 06/26/23
-0.017 0.297 34 12/07/23
-0.197 0.263 37C 03/28/23 0.206 0.244 37C 11/09/23 0.180 0.232
- COLLECTION LOCATION DATE Co-60 31 06/26/23
-0.008 31 11/07/23 0.001 32 06/12/23 0.020 32 12/14/23 0.034 33 06/26/23
-0.014 33 12/07/23 0.005 34 06/26/23 0.006 34 12/07/23
-0.002 37C 03/28/23 0.004 37C 11/09/23 0.038 C= Control location, Background location Results in bold type are positi..e.
(+/-)
0.049 0.046 0.044 0.059 0.039 0.041 0.037 0.032 0.035 0.037 TABLE 11 BOTTOM SEDIMENT (pCi/g dry wt.)
K-40 Cr-51
(+/-)
(+/-)
15.05 1.679
-0.120 0.456 15.44 1.793
-0.143 0.374 17.47 1.543
-0.036 0.478 13.05 1.545 0.405 0.575 11.56 1.342 0.067 0.274 15.02 1.608
-0.180 0.334 11.18 1.424 0.174 0.336 12.75 1.390 0.286 0.268 15.26 1.321 0.026 0.242 14.48 1.650
-0.103 0.266 Zn-65 Nb-95
(+/-)
(+/-)
-0.152 0.115 0.005 0.053 0.033 0.1 11
-0.012 0.052
-0.062 0.119 0.013 0.053
-0.074 0.139 0.018 0.066
-0.087 0.090 0.010 0.032
-0.025 0.150 0.045 0.050 0.029 0.108 0.043 0.040 0.030 0.086 0.031 0.039 0.037 0.080
-0.003 0.032
-0.069 0.109
-0.009 0.035 3-27 Annual Radiological Environmental Operating Report 2023 Mn-54 Co-58 Fe-59
(+/-)
(+/-)
(+/-)
0.018 0.048
-0.020 0.044
-0.090 0.112 0.050 0.052 0.003 0.045
-0.007 0.100
-0.004 0.052
-0.023 0.048 0.040 0.098 0.023 0.050
-0.072 0.052 0.000 0.122
-0.012 0.028
-0.002 0.033
-0.001 0.076
-0.039 0.050 0.011 0.045
-0.010 0.103 0.001 0.037
-0.029 0.042 0.033 0.091
-0.013 0.028
-0.009 0.031
-0.037 0.078 0.014 0.029
-0.017 0.030 0.019 0.062
-0.004 0.035 0.008 0.035 0.049 0.078 Zr-95 Ru-103 Ru-106
(+/-)
(+/-)
(+/-)
0.039 0.093
-0.046 0.056
-0.041 0.469 0.064 0.096 0.020 0.047
-0.060 0.473 0.030 0.091 0.033 0.055
-0.041 0.469
-0.032 0.1 05
-0.003 0.061 0.236 0.511 0.040 0.043
-0.004 0.032 0.100 0.237
-0.021 0.077 0.025 0.046
-0.053 0.369
-0.010 0.065 0.000 0.033 0.122 0.327 0.012 0.049 0.013 0.031 0.039 0.300 0.023 0.053 0.012 0.029
-0.050 0.244
-0.024 0.069 0.027 0.037
-0.334 0.276
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION LOCATION DATE Ag-110M 31 06/26/23 0.027 31 11/07/23
-0.010 32 06/12/23 0.009 32 12/14/23 0.019 33 06/26/23 0.001 33 12/07/23
-0.003 34 06/26/23
-0.013 34 12/07/23
-0.009 37C 03/28/23 0.001 37C 11/09/23
-0.020 C= Control location, Background location Results in bold type are positi-..e.
(+/-)
0.044 0.050 0.049 0.050 0.031 0.043 0.032 0.028 0.026 0.028 TABLE 11 BOTTOM SEDIMENT (pCi/g dry wt.)
Sb-125 1-131
(+/-)
(+/-)
0.071 0.135
-0.067 0.123 0.078 0.113
-0.041 0.070 0.019 0.131 0.018 0.097
-0.041 0.136
-0.077 0.177 0.110 0.089 0.008 0.067
-0.015 0.116 0.039 0.060
-0.020 0.096
-0.010 0.089 0.019 0.088
-0.014 0.056 0.018 0.081 0.038 0.047
-0.041 0.083
-0.025 0.076 3-28 Annual Radiological Environmental Operating Report 2023 Cs-134 Cs-137 Ac-228
(+/-)
(+/-)
(+/-)
0.067 0.054
-0.016 0.051 2.396 0.331 0.108 0.061
-0.001 0.054 3.096 0.513 0.093 0.060 0.014 0.056 2.305 0.378 0.080 0.058 0.011 0.054 0.903 0.342 0.024 0.030
-0.016 0.033 0.289 0.142 0.010 0.048
-0.008 0.048 0.134 0.171 0.019 0.042
-0.003 0.040 0.185 0.162 0.015 0.035
-0.022 0.033 0.085 0.134
-0.015 0.031
-0.007 0.027 0.056 0.132
-0.002 0.038
-0.023 0.031 0.213 0.162
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION LOCATION DATE Be-7 29 03/01/23 0.1280 29 06/01/23 0.0517 29 09/19/23 0.1956 29 11/07/23 0.0994 32 03/01/23 0.0268 32 06/08/23 0.0812 32 09/19/23 0.0922 32 12/04/23
-0.0044 35 03/06/23 0.2228 35 06/06/23 0.0355 35 09/19/23 0.0931 35 12/05/23 0.2175 36C 03/28/23 0.1723 36C 06/12/23 0.0560 36C 09/19/23 0.1481 36C 12/07/23 0.1984 C= Control location, Background location Results in bold type are positi-..e.
(+/-)
0.1341 0.1267 0.0964 0.1005 0.1008 0.1319 0.1247 0.1224 0.1015 0.0983 0.0970 0.1158 0.1166 0.1079 0.0959 0.1044 TABLE12 AQUATIC FLORA - FUCUS (pCi/g wet wt.)
K-40 Cr-51
(+/-)
(+/-)
5.8050 0.6226 0.0271 0.0913 6.7850 0.6265 0.0062 0.1135 5.3710 0.5095 0.0278 0.0783 6.5770 0.5313 0.0706 0.0949 5.2070 0.6028 0.0298 0.0873 6.9170 0.6926
-0.0057 0.1297 6.7760 0.7087
-0.0571 0.0972 6.4870 0.6139 0.0408 0.1022 5.8460 0.5428 0.0207 0.0763 5.4850 0.5507
-0.0642 0.1025 5.7890 0.5374
-0.0289 0.0821 5.9170 0.5365 0.0388 0.1109 3.8110 0.5079 0.0935 0.0819 5.8820 0.6156 0.0175 0.0850 5.3480 0.4604 0.0132 0.0890 6.8910 0.5344 0.0048 0.0875 3-29 Annual Radiological Environmental Operating Report 2023 Mn-54 Co-58 Fe-59
(+/-)
(+/-)
(+/-)
0.0036 0.0119
-0.0011 0.0142 0.0156 0.0339 0.0007 0.0146
-0.0121 0.0156
-0.0086 0.0243
-0.0072 0.0110 0.0055 0.0093
-0.0020 0.0239 0.0041 0.0134
-0.0030 0.0113
-0.0334 0.0291 0.0063 0.0111
-0.0064 0.0111
-0.0183 0.0283
-0.0074 0.0152
-0.0002 0.0160 0.0192 0.0291 0.0063 0.0124 0.0076 0.0140
-0.0006 0.0326
-0.0132 0.0144
-0.0053 0.0138
-0.0018 0.0305
-0.0017 0.0105 0.0013 0.0112
-0.0168 0.0289
-0.0049 0.0126
-0.0045 0.0122 0.0075 0.0256 0.0033 0.0112
-0.0016 0.0105 0.0087 0.0277
-0.0021 0.0121 0.0019 0.0123
-0.0113 0.0275 0.0084 0.0119
-0.0103 0.0094
-0.0149 0.0263
-0.0020 0.0125 0.0001 0.0116 0.0159 0.0259 0.0018 0.0104
-0.0029 0.0092 0.021 2 0.0231 0.0015 0.0104
-0.0045 0.0112
-0.0051 0.0273
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION LOCATION DATE Co-60 29 03/01/23 0.0066 29 06/01/23 0.011 3 29 09/19/23 0.0027 29 11/07/23 0.0045 32 03/01/23 0.0093 32 06/08/23 0.0142 32 09/1 9/23
-0.0023 32 12/04/23 0.0128 35 03/06/23
-0.0111 35 06/06/23
-0.0014 35 09/19/23
-0.0075 35 12/05/23 0.0137 36C 03/28/23
-0.0003 36C 06/12/23 0.0031 36C 09/19/23
-0.0012 36C 12/07/23 0.0090 C= Control location, Background location Results in bold type are positi.e.
(+/-)
0.0143 0.0130 0.0096 0.0130 0.0129 0.0169 0.0141 0.0146 0.0114 0.0118 0.0134 0.0144 0.0117 0.0139 0.0111 0.0127 TABLE12 AQUATIC FLORA - FUCUS (pCi/g wet wt.)
Zn-65 Nb-95
(+/-)
(+/-)
-0.0441 0.0372 0.0039 0.0111
-0.0170 0.0366 0.0107 0.0127
-0.0073 0.0242
-0.0050 0.0086
-0.0056 0.0362 0.0052 0.0120 0.0213 0.0363
-0.0052 0.0129 0.0220 0.0428
-0.0079 0.0161
-0.0075 0.0392 0.0009 0.0141
-0.0418 0.0394 0.0031 0.0135
-0.0146 0.0293
-0.0037 0.0113
-0.0055 0.0278
-0.0013 0.0116 0.0059 0.0302 0.0059 0.0106 0.0153 0.0337 0.0216 0.0124 0.0050 0.0254 0.0115 0.0103
-0.0192 0.0272
-0.0018 0.0139
-0.0067 0.0235
-0.0012 0.0098
-0.0253 0.0290
-0.0036 0.0115 3-30 Annual Radiological Environmental Operating Report 2023 Zr-95 Ru-103 Ru-106
(+/-)
(+/-)
(+/-)
-0.0001 0.0226 0.0008 0.0119
-0.0497 0.1159 0.0119 0.0259 0.0086 0.0134
-0.1192 0.1215 0.0060 0.0159 0.0017 0.0087 0.0174 0.0803 0.0206 0.0213 0.0119 0.0110
-0.0294 0.1062
-0.0056 0.0230
-0.0066 0.0115 0.0581 0.1134 0.0038 0.0317 0.0026 0.0143 0.0375 0.1423
-0.0127 0.0229 0.0145 0.0112 0.0716 0.1212 0.0152 0.0245
-0.0080 0.0134 0.0260 0.1231
-0.0119 0.0207 0.0040 0.0092
-0.0384 0.0999
-0.0074 0.0211
-0.0057 0.0121 0.0445 0.0988
-0.0157 0.0207
-0.0002 0.0102
-0.0134 0.0859
-0.0116 0.0204
-0.0072 0.0124
-0.0242 0.1062 0.0000 0.0223
-0.0003 0.0114 0.0417 0.1021 0.0084 0.0224
-0.0010 0.0109
-0.0763 0.1080
-0.0051 0.0167
-0.0048 0.0099
-0.0398 0.0779
-0.0071 0.0210 0.0014 0.0104
-0.0106 0.1107
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION LOCATION DATE Ag-110M 29 03/01/23
-0.0010 29 06/01/23
-0.0091 29 09/19/23 0.0011 29 11/07/23
-0.0053 32 03/01/23
-0.0029 32 06/08/23 0.0260 32 09/19/23
-0.0086 32 12/04/23
-0.0008 35 03/06/23 0.0071 35 06/06/23
-0.0105 35 09/19/23
-0.0005 35 12/05/23 0.0008 36C
.03/28/23
-0.0021 36C 06/12/23 0.0018 36C 09/19/23
-0.0001 36C 12/07/23 0.0014 C= Control location, Background location Results in bold type are positil.e.
(+/-)
0.0128 0.0115 0.0089 0.0112 0.0124 0.0159 0.0126 0.0140 0.0092 0.0123 0.0110 0.0118 0.0115 0.0106 0.0094 0.0100 TABLE12 AQUATIC FLORA - FUCUS (pCi/g wet wt.)
Sb-125 1-131
(+/-)
(+/-)
-0.0085 0.0303
-0.0052 0.0179
-0.0072 0.0347 0.0160 0.0286 0.0174 0.0231 0.0069 0.0142
-0.0083 0.0282 0.0166 0.0173 0.0042 0.0295
-0.0152 0.0172 0.0297 0.0444 0.0121 0.0259
-0.0234 0.0318
-0.0098 0.0176 0.0038 0.0350 0.0023 0.0177 0.0098 0.0277
-0.0091 0.0144 0.0032 0.0273 0.0090 0.0196 0.0122 0.0268 0.0052 0.0133
-0.0013 0.0341
-0.0043 0.0159 0.0112 0.0246 0.0103 0.0128 0.0182 0.0287
-0.0084 0.0146
-0.0132 0.0243 0.0084 0.0150 0.0152 0.0283
-0.0001 0.0157 3-31 Annual Radiological Environmental Operating Report 2023 Cs-134 Cs-137 Ac-228
(+/-)
(+/-)
(+/-)
-0.0035 0.0151 0.0114 0.0135 0.0503 0.0559 0.0172 0.0156 0.0070 0.0123 0.0903 0.0540
-0.0013 0.0111 0.0014 0.0098 0.0617 0.0433 0.0025 0.0129 0.0100 0.0113 0.0719 0.0497 0.0021 0.0130 0.0034 0.0140
-0.0020 0.0542 0.0075 0.0183
-0.0108 0.0171 0.1161 0.0557
-0.0025 0.0149
-0.0027 0.0159 0.0598 0.0529
-0.0016 0.0171
-0.0097 0.0155 0.1172 0.0693 0.0160 0.0128
-0.0074 0.0114 0.0490 0.0489 0.0018 0.0137 0.0054 0.0131 0.0661 0.0521
-0.0009 0.0114
-0.0001 0.0120 0.0083 0.0449 0.0062 0.0134
-0.0013 0.0128 0.0721 0.0557 0.0082 0.0137 0.001 7 0.0115 0.0663 0.0531
-0.0037 0.0159
-0.0075 0.0129 0.0663 0.0535 0.0031 0.0109 0.0039 0.0097 0.0547 0.0418 0.0101 0.0132
-0.0003 0.0111 0.0455 0.0543
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station COLLECTION LOCATION DATE Be-7
(+/-)
28 06/13/23 0.064 0.186 29 11/09/23 0.026 0.189 35 06/08/23 0.233 0.299 35 11/13/23 0.083 0.205 COLLECTION LOCATION DATE Co-60
(+/-)
28 06/13/23
-0.006 0.018 29 11/09/23 0.013 0.024 35 06/08/23
-0.006 0.042 35 11/13/23
-0.010 0.028 COLLECTION LOCATION DATE Ag-110M
(+/-)
28 06/13/23 0.001 0.020 29 11/09/23
-0.012 0.021 35 06/08/23 0.063 0.034 35 11/13/23 0.001 0.020 Results in bold type are positi1.e.
TABLE13 FISH (pCi/g wet wt.)
K-40 Cr-51
(+/-)
(+/-)
2.818 0.649
-0.102 0.204 4.196 0.625
-0.022 0.206 4.203 0.951 0.033 0.283 3.856 0.702 0.109 0.233 Zn-65 Nb-95
(+/-)
(+/-)
-0.035 0.050 0.013 0.023
-0.070 0.057 0.011 0.023
-0.081 0.076
-0.018 0.037
-0.027 0.058 0.004 0.027 Sb-125 1-131
(+/-)
(+/-)
0.009 0.048
-0.028 0.057
-0.004 0.056
-0.022 0.053 0.013 0.086
-0.014 0.057 0.009 0.066 0.039 0.045 3-32 Mn-54
(+/-)
-0.011 0.020 0.003 0.021
-0.002 0.034 0.000 0.023 Zr-95
(+/-)
-0.018 0.038 0.010 0.041 0.016 0.064 0.018 0.041 Cs-134
(+/-)
-0.006 0.020 0.016 0.023 0.009 0.040 0.000 0.025 Annual Radiological Environmental Operating Report 2023 Co-58 Fe-59
(+/-)
(+/-)
-0.006 0.021 0.020 0.046 0.004 0.023 0.025 0.046 0.010 0.032 0.086 0.075 0.012 0.024
-0.023 0.052 Ru-103 Ru-106
(+/-)
(+/-)
-0.005 0.021 0.042 0.177
-0.014 0.022 0.034 0.192
-0.001 0.030
-0.108 0.303
-0.003 0.025
-0.028 0.250 Cs-137 Ac-228
(+/-)
(+/-)
0.024 0.020 0.021 0.077 0.006 0.023
-0.037 0.094 0.024 0.027
-0.056 0.139
-0.013 0.023 0.100 0.121
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station LOCATION 31 31 89C 89C LOCATION 31 31 89C 89C LOCATION 31 31 89C 89C COLLECTION DATE 06/26/23 11/14/23 05/11/23 07/13/23 COLLECTION DATE 06/26/23 11/14/23 05/11/23 07/13/23 COLLECTION DATE 06/26/23 11/14/23 05/11/23 07/13/23 Be-7
(+/-)
0.092 0.262 0.073 0.288 0.056 0.207 0.102 0.203 Co-60
(+/-)
-0.019 0.034 0.002 0.038
-0.005 0.028 0.020 0.025 Ag-110M
(+/-)
-0.002 0.026
-0.001 0.037
-0.022 0.023 0.012 0.022 C= Control location, Background location Results in bold type are positi1.e.
TABLE14 OYSTERS (pCi/g wet wt.)
K-40 Cr-51
(+/-)
(+/-)
2.068 0.929
-0.077 0.270 1.475 0.779
-0.111 0.246 2.039 0.581
-0.016 0.200 1.458 0.690 0.183 0.250 Zn-65 Nb-95
(+/-)
(+/-)
-0.046 0.080 0.020 0.033
-0.118 0.105 0.019 0.039 0.016 0.055
-0.018 0.025
-0.003 0.067
-0.037 0.026 Sb-125 1-131
(+/-)
(+/-)
-0.067 0.078
-0.021 0.042 0.040 0.087
-0.061 0.050
-0.012 0.048
-0.011 0.047
-0.009 0.061 0.014 0.042 3-33 Mn-54
(+/-)
0.004 0.032 0.037 0.039 0.010 0.023
-0.017 0.018 Zr-95
(+/-)
0.006 0.055 0.038 0.060
-0.020 0.041 0.031 0.043 Cs-134
(+/-)
-0.016 0.032 0.014 0.038 0.020 0.020
-0.029 0.026 Annual Radiological Environmental Operating Report 2023 Co-58
(+/-)
0.010 0.026
-0.005 0.030
-0.002 0.024
-0.018 0.021 Ru-103
(+/-)
0.001 0.029 0.012 0.037
-0.017 0.025
-0.002 0.026 Cs-137
(+/-)
0.006 0.032 0.022 0.041 0.011 0.022
-0.018 0.024 Fe-59
(+/-)
-0.024 0.066 0.014 0.069 0.007 0.053
-0.016 0.053 Ru-106
(+/-)
-0.101 0.302
-0.007 0.351
-0.041 0.205
-0.221 0.261 Ac-228
(+/-)
0.143 0.128 0.005 0.130
-0.023 0.090 0.043 0.098
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station LOCATION 29 29 31 31 LOCATION 29 29 31 31 LOCATION 29 29 31 31 COLLECTION DATE 06/06/23 11/27/23 06/29/23 12/05/23 COLLECTION DATE 06/06/23 11/27/23 06/29/23 12/05/23 COLLECTION DATE 06/06/23 11/27/23 06/29/23 12/05/23 Results in bold type are positi1.e.
Be-7
(+/-)
0.066 0.235 0.047 0.232 0.033 0.225 0.021 0.172 Co-60
(-iT-)
0.007 0.033
-0.002 0.033 0.038 0.036 0.024 0.031 Ag-110M
(+/-)
0.000 0.030 0.008 0.022 0.017 0.027 0.007 0.022 TABLE15 CLAMS (pCi/g wet wt.)
(+/-)
1.839 0.632 2.046 0.637 2.038 0.668 2.122 0.696 Zn-65
(+/-)
-0.023 0.059 0.054 0.064 0.017 0.073
-0.029 0.058 Sb-125
(+/-)
0.052 0.067 0.035 0.070
-0.016 0.067
-0.028 0.073 Cr-51
(+/-)
-0.185 0.260
-0.010 0.264 0.056 0.243 0.047 0.209 Nb-95
(+/-)
0.003 0.029
-0.006 0.034
-0.010 0.029 0.003 0.025 1-131
(+/-)
0.022 0.045
-0.010 0.045
-0.012 0.056 0.005 0.029 3-34 Mn-54
(+/-)
-0.004 0.028
-0.007 0.028 0.002 0.026
-0.014 0.026 Zr-95
(+/-)
-0.001 0.055 0.038 0.048 0.000 0.049 0.041 0.042 Cs-134
(+/-)
0.000 0.032
-0.019 0.029 0.014 0.029
-0.009 0.025 Annual Radiological Environmental Operating Report 2023 Co-58
(+/-)
0.018 0.025 0.000 0.030 0.007 0.026
-0.019 0.025 Ru-103
(+/-)
0.022 0.028
-0.022 0.027 0.012 0.028
-0.015 0.022 Cs-137
(+/-)
-0.009 0.033
-0.021 0.030
-0.002 0.031
-0.024 0.025 Fe-59
(+/-)
-0. 001
- 0. 059
-0.044 0.057 0.021 0.052 0.014 0.038 Ru-106
(+/-)
0.178 0.298
-0.061 0.219 0.037 0.246 0.033 0.243 Ac-228
(+/-)
-0.015 0.124
-0.014 0.098
-0.052 0.115
-0.020 0.107
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station LOCATION 35 35 89C 89C LOCATION 35 35 89C 89C LOCATION 35 35 89C 89C COLLECTION DATE 06/08/23 07/17/23 05/30/23 08/16/23 COLLECTION DATE 06/08/23 07/17/23 05/30/23 08/16/23 COLLECTION DATE 06/08/23 07/17/23 05/30/23 08/16/23 Be-7
(+/-)
0.128 0.097
-0.184 0.235 0.187 0.244 0.205 0.247 Co-60
(+/-)
0.005 0.010
-0.013 0.036 0.023 0.032 0.017 0.038 Ag-110M
(+/-)
-0.006 0.010
-0.002 0.032 0.016 0.025
-0.002 0.022 C= Control Location, Background location Results in bold type are positi~.
TABLE16 LOBSTERS (pCi/g wet wt.)
(+/-)
1.984 0.321 2.546 0.886 2.785 0.823 2.230 0.700 Zn-65
(+/-)
0.005 0.026
-0.016 0.083
-0.060 0.065
-0.096 0.073 Sb-125
(+/-)
0.011 0.029 0.025 0.079
-0.006 0.066
-0.031 0.079 Cr-51
(+/-)
-0.042 0.103
-0.133 0.260
-0.058 0.225 0.039 0.208 Nb-95
(+/-)
0.012 0.013
-0.038 0.029
-0.005 0.037
-0.010 0.028 1-131
(+/-)
0.011 0.020
-0.007 0.038
-0.020 0.046
-0.005 0.039 3-35 Mn-54
(+/-)
0.000 0.010
-0.013 0.026
-0.010 0.023 0.008 0.029 Zr-95
(+/-)
-0.017 0.021
-0.029 0.062 0.065 0.051 0.006 0.049 Cs-134
(+/-)
0.012 0.013 0.013 0.043
-0.003 0.042
-0.012 0.028 Annual Radiological Environmental Operating Report 2023 Co-58
(+/-)
0.001 0.010
-0.012 0.031 0.022 0.032
-0.004 0.028 Ru-103
(+/-)
-0.010 0.011
-0.008 0.029 0.011 0.029 0.010 0.024 Cs-137
(+/-)
0.001 0.011
-0.005 0.038 0.011 0.026
-0.002 0.021 Fe-59
(+/-)
-0.008 0.022
-0.005 0.078 0.006 0.057 0.023 0.049 Ru-106
(+/-)
-0.038 0.097
-0.184 0.318
-0.049 0.247 0.104 0.240 Ac-228
(+/-)
0.162 0.064
, 0.087 0.140 0.040 0.118 0.091 0.099
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station
- 4. DISCUSSION OF RESULTS Annual Radiological Environmental Operating Report 2023 This section summarizes the results of the analyses on the REMP samples. Station related tritium (H-3) radioactivity was detected in seawater collected at the quarry discharge point. This was within the station boundary. The naturally occurring nuclides of Be-7, K-40, and Ac-228, were detected in some samples. Be-7 is from cosmic radiation.
It was observed in fruits, vegetables, air, and broad leaf vegetation samples. K-40 and Ac-228 are two common terrestrial isotopes. K-40 was not seen in well water samples but was observed in other samples. Ac-228 was observed in bottom sediment, soil, and lobsters samples. Cs-137 and Sr-90 from atmospheric nuclear weapons testing in the 1960's has been observed in the past. A study by the Connecticut Department of Energy and Environmental Protection in 2006 affirmed that radioactivity from nuclear weapons testing has decreased to almost non-detectable levels (Reference 19). Since 2006 detection of Cs-137 and Sr-90 in environmental samples has been rare. Cs-137 from nuclear weapons testing was detected above MDC at two locations and at MDC (Minimum Detectable Concentration) at one location in 2023. Based on sample location, it is expected to identify the presence of Cs-137 in undisturbed soil22* The remaining REMP samples obtained during 2023 did not indicate the presence of Cs-137 and the overall trend is decreasing (Figure 4.5-1 ).
4.1 Gamma Exposure Rate (Table 1)
Gamma exposure rate is determined from the integrated exposure measured over a calendar quarter using TLDs. Prior to 1990, Victoreen CaF2(Mn) glass bulb dosimeters were used for these measurements. In 1990, these were replaced by Harshaw CaF2(Mn) chips. In 2000, the CaF2(Mn) TLDs, were replaced with the CaSO4(Tm) Panasonic model UD-814 AS1 TLDs.
Readings are recorded as µR/hr. The unit µR stands for 'micro-roentgen' with a 'micro' being one-millionth of a roentgen. A roentgen is the quantity of radiation equal to 87.6 ergs of energy per gram of air. For gamma exposure a micro-roentgen is equivalent to a micro-rem, a measure of dose to man.
The dosimeters are strategically placed at several onsite locations, as well as at inner and outer offsite locations. Starting in 2001, the collection of TLDs was changed from monthly to quarterly and additional measurement locations were incorporated into the REMP requirements listed in the REMODCM (Reference 8). Three more locations (73-75) were added in mid-2003 to prepare for monitoring the potential effect from the ISFSI. Two dry cask containers were loaded in the first quarter of 2005, three in 2006, three in 2007, three in 2009, three in 2010, four in 2012, six in 2015, five in 2016, three in 2018, seven in 2019, six in 2021, two in 2022, and three in 2023.
Prior to any cask loading, the background readings average recorded from mid 2003 - 2004 were: 9.5 µR/hour at Location 73, 7.5 µR/hour at Location 74, and 6.9 µR/hour at Location 75.
In 2023, the annual average exposure rate measurement for the ISFSI area was 7.5 µR/hour at Location 73, 7.4 µR/hour at Location 74, and 6.5 µR/hour at Location 75. The station offsite dose from ISFSI for 2023 was 0.041 mrem/year, which is below the 25 mrem/year limit per 40.190 CFR.
4-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Table 1 in Section 3.2 lists the exposure rate measurements for all 43 monitored locations.
These measurements demonstrate the general variations in background radiation between the various onsite and offsite locations and include gamma exposure from all sources of radioactivity.
For example, the Weather Shack (Location 2), Quarry East (Location 5), Environmental Laboratory (Location 8), Bay Point Beach (Location 9), Goshen Fire Dept (Location 10), and Corey Road (Location 48) experience higher exposure rates due to their proximity to granite beds and stonewalls. In addition, the control locations in Mystic, Ledyard, Norwich, and Old Lyme (Location 13C, 14C, 15C, and 16C) had background exposure rates consistent with rates seen in the past years.
Figure 4.1-1 shows a historical trend of TLD exposure rate measurements, comparing an annual average of all indicator TLDs, an annual average of all control TLDs, and the annual average of the two most critical indicator locations, location 1 and 3, which are used to represent the two closest site boundary residences in the North-northwest and Northeast directions. The average indicator and control readings were both about 8.0 µR/hour.
Figure 4.1 -1 also relates the difference in indicator locations 1 and 3 and the annual average of all indicator TLDs to the annual average of the control TLDs collected and measured during coincident periods throughout the year. Locations 1 and 3 are important because they are onsite and located between the plant and nearby populated areas. As discussed earlier, the exposure measurements of many indicator locations onsite (and two of the control locations) are influenced by natural background exposure differences caused by the many granite outcroppings typical of the local area. Figure 4.1-1 shows that the annual average at indicator Location 3 was lower in gamma exposure rate than the average control gamma exposure rate. These differences are the result of the differences in granite at these locations. Location 3 was moved in the second quarter 2009 to minimize the effect of tree covering for the air sampler also located at this location. The 2000 to 2009 data for Location 3 shows an increase likely attributable to 1-3 µR/hr gradients observed from the granite bedrock of the MPS Site (Reference 21 ). Over the last 10 years there has been no significant change in the annual gamma exposure rate (Figure 4.1 -1 ); the small variation in the results for all indicators, location 1, and locations 3 are expected due to counting statistical variation.
4-2
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Figure 4.1-1 Annual Radiological Environmental Operating Report 2023 Annual Gamma Exposure Rate - 20 Year History i...
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 4.2 Air Particulate Gross Beta Radioactivity {Table 2)
Annual Radiological Environmental Operating Report 2023 Air is continuously sampled at seven inner ring (0 to 2 miles) locations and one control location (14 miles N) by passing it through glass fiber particulate filters. These samples are collected every two weeks and analyzed for gross beta radioactivity. Results are shown on Figure 4.2-1 and Table 2. Gross beta activity remained at levels similar to that seen over the last decade.
Indicators and control monitoring locations continue to show no significant variation in measured activities and are within the expected calculated uncertainty of +/-0.002 pCi/m3 (see Figure 4.2-2).
This indicates that any station contribution is not measurable.
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 4.3 Airborne Iodine (Table 3)
Annual Radiological Environmental Operating Report 2023 Charcoal cartridges are included at all the air particulate monitoring stations for the collection of atmospheric iodine. These cartridges were analyzed for 1-131 every two weeks. No detectable levels of 1-131 were seen in the 2023 charcoal samples.
4.4 Air Particulate Gamma (Table 4)
The air particulate samples that are utilized for the gross beta analyses are composited quarterly and analyzed for gamma emitting isotopes including strontium analysis as a substitute for milk analysis. The results, as shown in Table 4, indicate the presence of naturally occurring Be-7, which is produced by cosmic radiation. No other positive results are seen. These analyses indicate that there was not any detectable station related radioactivity in the air samples.
4.5 Soil (Table 5)
This media is collected annually from one control and two indicator locations. MPS has collected and analyzed soil since 2001. Prior to 2001, soil had not been sampled for over fifteen years because station related detectable activity had not been detected.
Since 2001 no station detectable activity has been seen in these samples. Naturally occurring nuclides K-40 and Ac-228 were detected in soil. Cs-137 from nuclear weapons testing was detected slightly above MDC (Minimum Detectable Concentration) in one soil indicator samples in 2023. The control location was below MDC. The results of these samples, allows for the determination of baseline activity levels in soil. This is particularly important for Cs-137 since significant levels from past weapons testing fallout remain in the soil. Figure 4.5-1 shows the trend of Cs-137 in soil samples, the trend appears to be declining with time with an expected counting statistical variation observed over the last 15 years. Baseline levels should be useful in the future, when site characterization and decommissioning of the station become the focus during preparations for license termination.
2 1.8 1.6 e
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- Bird Sanctuary, 0.3 Mile NE Albacore Dr 1.0 Mile N
, **, Ledyard 12 Miles NE I
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 4.6 Milk (Table 6)
Annual Radiological Environmental Operating Report 2023 Each year the Land Use Census is used to identify locations of milk animals that should be included in the monitoring program. It is performed annually and is maintained by observations, door-to-door surveys, and consulting with local agriculture authorities. The 2023 census is listed in Appendix A. If a new dairy farm is identified close enough to MPS to be considered an indicator location, the collection of milk at that location would be added.
In 2023, the Land Use Census did not locate any location of commercial milk farms within 1 O miles of Millstone Power Station. Prior to 2018, milk samples were obtained and analyzed for strontium from a farm that is no longer producing milk. A valid substitute for milk analysis is air filters strontium analysis and gamma analysis of broad leaf vegetation. This strontium analysis of air filter was determined to be more effective than milk analysis, (Reference 23). The air sampling stations are located closer to the plant and in the predominant downwind direction.
- 4. 7 Well Water (Table 7)
All REMP wells samples including ISFSI wells samples were less than the Lower Level of Detection Limit (LLD). Additional samples from other wells were obtained as part of the Groundwater Protection Program (GWPP). Results from the GWPP are reported in the MPS annual "Radioactive Effluent Release Report" for 2023. ISFSI wells results have been documented in Table 7 as required by the Connecticut Siting Council.
4.8 Fruits and Vegetables (Table 8)
Consistent with past years, this media did not show any station effects. Naturally occurring nuclides Be-7 and K-40 were the only isotopes detected in the samples.
4.9 Broad Leaf Vegetation (Table 9)
Consistent with past years, this media did not show any station effects. Most samples had detectable levels of cosmic produced Be-7 and naturally occurring K-40. Occasionally these samples have indicated positive levels of Cs-137 in the past. This can be attributed to fallout from weapons testing which has been widespread in terrestrial samples for many years. Cs-137 was not detected in any of the 2023 collected Broad Leaf Vegetation samples.
4.10 Seawater (Table 10)
The guidance in Reference 15 specifies one sample upstream (control - beyond significant influence of the discharge) and one sample downstream (indicator-beyond but near the mixing zone) for surface water samples. Historically the downstream sample for MPS has been located in the vicinity of discharge (Location 32) which is prior to the mixing zone. This location was chosen since it was readily accessible and not affected by cold weather conditions. Operation of an automatic sampler at the indicator location is necessary for providing a representative sample.
Any dose consequences can be assessed by use of the appropriate dilution factors. It is not necessary to have a continuous sampler at the control location due to the historical relative consistency noted in seawater background activity near the Millstone.
A technician collects an aliquot from the automatic sampler at Location 32 on a weekly frequency.
These samples are composited for monthly analyses. For the Control Location, Giant's Neck (Location 37C), six weekly grab samples are obtained for quarterly compositing.
Naturally occurring K-40 was the only detectable gamma activities seen in these samples.
Measured station related levels of H-3, beta activity, in seawater from the vicinity of discharge (Location 32) were observed in most samples. Tritium releases are typically higher near outages due to the need for increased liquid processing during these times. As mentioned above, these 4-6
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 samples are taken directly from liquid effluent flow prior to dilution into the Long Island Sound.
Tritium builds up in the reactor coolant during each fuel cycle. It is generated during station operation from fission and neutron reactions. Figure 4.10-1 shows an eighteen-year trend of Tritium (H-3) releases in the MPS liquid effluents versus the measured environmental concentrations from the vicinity of discharge location. In 2023 MPS had one outage requiring the processing and subsequent discharge of processed refueling water. The highest quarterly average H-3 value in 2023 for seawater was 1,043 pCi/I, which is well below the drinking water limit established by the Environmental Protection Agency (EPA) of 20,000 pCi/1. The total annual exposure from the liquid discharge pathway for 2023 was 0.001 mrem/yr.
2,000
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- 3 1,000
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-*- Curies discharged
-- REMP pCi/liter Date 4-7 2,000
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station 4.11 Bottom Sediment (Table 11)
Annual Radiological Environmental Operating Report 2023 There was no station related radioactivity detected in bottom sediment samples in 2023.
Naturally occurring K-40 is seen in all samples and naturally occurring Ac-228 in some samples.
Bottom sediment is not a significant dose pathway to man, especially at areas not typically used by the public.
4.12 Aquatic Flora (Table 12)
Aquatic flora is a sensitive indicator of low levels of man-made radioactivity (e.g., Mn-54, Co-58, Co-60, Zn-65, 1-131 and Ag-11 Om) in the environment so it was added as a required sample at four locations in revision 28 of the REMODCM. Naturally occurring K-40 was the only isotope detected in the samples.
4.13 Fish (Table 13)
The activity in fish is the same as that seen in the past. No activity was observed except for the naturally occurring K-40.
4.14 Oysters (Table 14)
All locations utilize oysters stocked in trays. Oyster sampling has occasionally presented challenges in obtaining the sample size required for analysis. In 2023 four adequately sized for analysis samples were obtained. Only naturally occurring K-40 was detected in the collected samples. No plant related radioactivity was detected in oysters in 2023.
4.15 Clams (Table 15)
In 2023, only the naturally occurring K-40 was detected in the collected samples.
4.16 Lobsters (Table 16)
In 2023, only the naturally occurring isotopes, K-40 and Ac-228, were detected in the collected samples 4-8
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station
- 5. REFERENCES Annual Radiological Environmental Operating Report 2023
- 1)
United States of America, Code of Federal Regulations, Title 10, Part 50, Appendix A Criteria 64.
- 2)
Donald T. Oakley, "Natural Radiation Exposure in the United States," U.S. Environmental Protection Agency, ORP/SID 72-1, June 1972.
- 3)
National Council on Radiation Protection and Measurements, Report No. 160, "Ionizing Radiation Exposures of the Population of the United States," March 2009.
- 4)
National Council on Radiation Protection and Measurements, Report No. 94, "Exposure of the Population of the United States and Canada from Natural Background Radiation,"
December 1987.
- 5)
United States Nuclear Regulatory Commission, Regulatory Guide 8.29, "Instructions Concerning Risks from Occupational Radiation Exposure," Revision 0, July 1981.
- 6)
United States of America, Code of Federal Regulations, Title 10, Part 20.1302.
- 7)
United States Nuclear Regulatory Commission, Regulatory Guide 1.109, "Calculation of Annual Doses to Man from Routine Releases of Reactor Effluents for the Purpose of Evaluating Compliance with 10 CFR Part 50, Appendix I," Revision 1, October 1977.
- 8)
Millstone Power Station Radiological Effluent Monitoring and Offsite Dose Calculation Manual, Revision 30, September 19, 2018
- 9)
Millstone Power Station Unit 1 Defueled Technical Specifications, License No. DPR-21.
- 10) Millstone Power Station Unit 2 Technical Specifications, License No. DPR-65.
- 11) Millstone Power Station Unit 3 Technical Specifications, License No. NPF-49.
- 12) United States Nuclear Regulatory Commission, Regulatory Guide 4.1, "Program for Monitoring Radioactivity in the Environs of Nuclear Power Plants," Rev. 1, April 1975.
- 13) ICN/Tracerlab, "Millstone Power Station Pre-Operational Environmental Radiation Survey Program, Quarterly Reports," April 1967 to June 1970.
- 14) International Commission of Radiological Protection, Publication No.43, "Principles of Monitoring for the Radiation Protection of the Population," May 1984.
- 15) United States Nuclear Regulatory Commission, NUREG-1301, "Offsite Dose Calculation Manual Guidance:
Standard Radiological Effluent Controls for Pressurized Water Reactors," April 1991.
- 16) United States Nuclear Regulatory Commission, Branch Technical Position, "An Acceptable Radiological Environmental Monitoring Program", Rev. 1, November 1979.
- 17) Reassessment of Millstone Power Station's Environmental Monitoring Data, Connecticut Department of Environmental Protection, Division of Radiation, March 2006.
- 18) Nuclear Regulatory Commission Regulatory Guide 4.1, Radiological Environmental Monitoring for Nuclear Power Plants, Revision 2, June 2009.
- 19) Division of Radiation, CT Dept. of Energy and Environmental Protection, "Reassessment of Millstone Power Station's Environmental Monitoring Data," January 2006.
- 20) Connecticut Sitting Council Decision and Order for ISFSI, Docket No. 265, May 27, 2004.
- 21) RP-16-08, "Take-Home Thermoluminescent Dosimeter Variance", June 17, 2016.
- 22) MP-HPO-98137, "Determination of Cs-137 In Undisturbed Soil At Locations Greater Than 10 Miles From Millstone Site", July 28, 1998.
- 23) MP-HPO-17067, "Milk Availability for the Radiological Environmental Monitoring Program",
October 11, 2017.
5-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station APPENDIX A Annual Radiological Environmental Operating Report 2023 LAND USE CENSUS FOR 2023 A-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 The annual land use census in the vicinity of MPS was conducted as required by the MPS REMODCM. Table A-1 is a list of closest residents in each of twelve over-land compass sectors around Millstone. The list of residents was determined by a survey of properties around Millstone using Google Earth and verified by a field survey. It was assumed that the closest resident was also the closest garden. No changes from the 2022 closest resident list were identified.
Table A-2 is a list of milk and other foods within ten miles of Millstone. Cow and goat milk producers were identified using the State of Connecticut Agriculture Department list of licensees and using American Dairy Goat Association (ADGA). There were no animals producing milk located within ten miles of Millstone Power Station. As a substitute for milk samples, strontium analysis of air filter and gamma analysis of broad leaf vegetation are being performed on quarterly basis.
Other sources of food were obtained from the Internet at http://www.farmfresh.org by searching for businesses closest to Waterford, CT. A search using Google Earth and field surveys were used to identify additional sources, Figure A-1. No changes from the 2022 sources of food locations were identified.
The 2023 Land Use Census also evaluated aquatic sampling exposure pathways from the fish and shellfish located around MPS. Figure A-2 shows shellfish beds around MPS from the Bureau of Aquaculture of the Department of Agriculture. The saltwater fishing areas are identified in Figure A-3. No changes from the 2022 aquatic sampling exposure pathways were identified.
The dose modeling incorporates the distances listed in Tables A-1, A-2.
A-2
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Table A-1 2023 S urvey Downwind Resident/Garden 1 Direction miles meters N
0.95 1,529 NNE 0.53 853 NE 0.47 756 ENE 0.50 805 E
0.92 1,481 ESE 1.06 1,706 SE2 N/A N/A SSE2 N/A N/A s2 N/A N/A ssw2 N/A N/A SW 2.28 3,669 WSW 1.95 3,138 w
1.78 2,865 WNW 1.51 2,430 NW 1.35 2,173 NNW 0.51 821 Notes:
- 1. No gardens located closer than resident.
Annual Radiological Environmental Operating Report 2023
A-3
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Table A-2 Dairy and food producers within Ten miles of Millstone - 2023 Sector Miles Business Location Comments NW 1.95 Smith's Acres Niantic Fruits and vegetables NE 1.96 Mingo Goat Waterford Registered ADGA member only, no goats on site.
ENE 2.8 Secchiaroli Farms Waterford Has pigs, fed nonlocal sources and have concrete pens N
3.2 Scotts' Farm &
Waterford Fruits and vegetables Garden WNW 5.0 Four Mile River Farm Old Lyme Eggs, Meat NW 5.2 Scott's Yankee East Lyme Fruits, vegetables, and cider Farmer NNW 5.3 White Gate Farm East Lyme Vegetables, Herbs, Eggs, Meat, Nursery, and Flowers ENE 6.8 Leverett Goat Groton Registered ADGA member only, no goats on site.
N 7.4 Hunts Brook Farm Quaker Hill Honey, Maple, and Vegetables ENE 7.5 Groton Family Farm Groton Vegetables, Honey, Maple, and Eggs NE 8.3 Red Fence Farm Groton Fruits, vegetables, cows, and pig.
Cows not producing milk N
9.2 Valchris Farm Oakdale Organic Fruits & Vegetables Table A-3 C urren ts amI DlnQ ocaIons or eqe a I0n -
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Figure A-1 Annual Radiological Environmental Operating Report 2023 Farms and Goats Products within ten miles of Millstone A-5
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Figure A-2 Shellfish Beds in Vicinity of Millstone
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Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station APPENDIX B Annual Radiological Environmental Operating Report 2023
SUMMARY
OF INTERLABORATORY COMPARISONS B-1
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Summary of Results - Inter-laboratory Comparison Program (ICP)
The TBE Laboratory analyzed Performance Evaluation (PE) samples of air particulate (AP), air iodine, milk, soil, vegetation, and water matrices that represent test & matrix combinations available for REMP programs. 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 TBE's 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 ERA's evaluation report provides an acceptance range for control and warning limits with associated flag values. ERA's acceptance limits are established per the US EPA, National Environmental Laboratory Accreditation Conference (NELAC), state-specific Performance Testing (PT) program requirements or ERA's 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 MAPEP's 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 always resemble typical environmental samples obtained at commercial nuclear power facilities.
For the TBE laboratory, 124 out of 131 analyses performed met the specified acceptance criteria.
Seven analyses did not meet the specified acceptance criteria and were addressed through the TBE Corrective Action Program. A summary is found below:
- 1. The MAPEP February 2023 Soil Ni-63 result was evaluated as Not Acceptable. TBE's reported value was 294 Bq/kg and the known result was 1130 Bq/kg (range 791 - 1469).
The sample was reprepped by a different (senior) lab technician with results of 1120 &
1250 Bq. It was determined that there was a difference between the two techs during the sample prep (technique) and the procedure was revised to reflect these differences including using a specific aliquot amount. (NCR 23-08)
- 2. The MAPEP February 2023 vegetation Sr-90 result was evaluated as Not Acceptable.
The reported value was 0.05 Bq (not detected) and the known result was a "false positive". This was considered to be a statistical failure because TBE's reported result with 3 times the uncertainty resulted in a slightly positive net result (0.03194 Bq/kg). The B-2
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 reported result was significantly below TBE's average detection limit for vegetation samples. (NCR 23-09)
- 3. The ERA RAD February 2023 water Ba-133 result was evaluated as Not Acceptable. The reported value was 26.0 pCi/L and the known was 22.3 (acceptance range 17.1 - 25.8 pCi) or 117% of the known (acceptable for TBE QC). The sample was used as the workgroup duplicate with a result of 25.4 (114%). The sample had also been counted on a different detector with a result of 21.9 (98%). The was TBE's first failure for Ba-133.
(NCR 23-10)
- 4. The MAPEP August 2023 soil Fe-55 result was evaluated as Not Acceptable. The reported value was 346 Bq/kg and the known result was 1280 (acceptance range of 896-1664 Bq/kg). This was TB E's initial evaluation for Fe-55 in soils. The result was received at the end of December and the root cause in under investigation. No client samples were associated with this cross-check. (CAR 23-31)
- 5. The Analytics September 2023 milk Sr-90 result was evaluated as Not Acceptable. The reported result was 7.28 pCi/L and the known result was 12.8 (57% of known). This sample was used as the workgroup duplicate and the carrier yields for both samples were 107% and 75%. The LCS recovery for the workgroup was at 106%. The ERA drinking water Sr-90 cross check that was analyzed around the same time was acceptable at 108%. There was no explanation for the failure. This is the first low biased failure for Sr-90 milk. The last failure (high) was in 2016. (NCR 23-24)
- 6. The ERA RAD October 2023 water Gross Alpha result was evaluated as Not Acceptable.
The reported result was 53.2 pCi/L and the known result was 70.6 (acceptable range of 54.0- 87.2 pCi/L). The reported result was the workgroup duplicate and was within 75%
of the known value (within TBE QC range). The original result was 63.3 pCi/L (90% of the known). Because the LCS result was biased slightly high, the decision was made to report the lower value. (NCR 23-20)
- 7. The ERA RAD October 2023 water 1-131 result was evaluated as Not Acceptable. The reported value was 23.5 pCi/L and the known result was 29.7 (acceptable range of 25.8
- 33.6) The reported result was 79% of the known, which is within the acceptable TBE QC range. The workgroup was reviewed with no anomalies found. The LCS/LCSD results were 109% and 86.1 %. The sample was not processed in a timely manner as per the ERA instructions which stated to analyze shortly after receipt due to the short half-life. Going forward, the QA &/or Lab Mgr. will ensure that this analysis is started sooner.
(NCR 23-21)
The Inter-Laboratory Comparison Program provides evidence of "in control" counting systems and methods, and that the laboratories are producing accurate and reliable data.
B-3
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 Analytics Environmental Radioactivity Cross Check Program I~l!Ub£ll~ ac12l0!1J i;;1Jgiml~Ci1Jg i;;1Jll:i[!21llll~llli1I S~Cll:i!.~l:i Identification TBE Known Ratio ofTBE to Month/Year Number Matrix Nuclide Units Reported Value (a)
Analytics Result Evaluation ibl Value March 2023 E13826 Milk Sr-89 pCi/L 70.5 93.1 0.76 w
Sr-90 pCi/L 12.3 14.7 0.84 A
E13827 Milk Ce-141 pCi/L 127 139 0.91 A
Co-58 pCi/L 119 131 0.91 A
Co-60 pCi/L 250 279 0.90 A
Cr-51 pCi/L 246 302 0.82 A
Cs-134 pCi/L 172 200 0.86 A
Cs-137 pCi/L 125 140 0.89 A
Fe-59 pCi/L 122 122 1.00 A
1-131 pCi/L 70.2 82.0 0.86 A
Mn-54 pCi/L 165 180 0.92 A
Zn-65 pCi/L 306 306 1.00 A
E13828 Charcoal 1-131 pCi 79.0 89.9 0.88 A
E13829 AP Ce-141 pCi 91.9 87.8 1.05 A
Co-58 pCi 87.5 82.5 1.06 A
Co-60 pCi 199 176 1.13 A
Cr-51 pCi 218 191 1.14 A
Cs-134 pCi 119 126 0.94 A
Cs-137 pCi 92.4 88.7 1.04 A
Fe-59 pCi 95.5 76.9 1.24 w
Mn-54 pCi 120 113 1.06 A
Zn-65 pCi 179 193 0.93 A
E13830 Soil Ce-141 pCi/g 0.224 0.220 1.02 A
Co-58 pCi/g 0.193 0.207 0.93 A
Co-60 pCi/g 0.406 0.441 0.92 A
Cr-51 pCi/g 0.464 0.477 0.97 A
Cs-134 pCi/g 0.334 0.316 1.06 A
Cs-137 pCi/g 0.270 0.288 0.94 A
Fe-59 pCi/g 0.183 0.193 0.95 A
Mn-54 pCi/g 0.263 0.284 0.93 A
Zn-65 pCi/g 0.475 0.484 0.98 A
E13831 AP Sr-89 pCi 99.4 90.8 1.09 A
Sr-90 pCi 14.6 14.3 1.02 A
(a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) Analytics evaluation based on TBE internal QC limits:
A= Acceptable - reported result falls within ratio limits of 0.80-1.20 W = Acceptable with warning - reported result falls within 0.70-0. 80 or 1.20-1.30 B-4
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 Analytics Environmental Radioactivity Cross Check Program I~l!U;i)!D~ ac'2l0£D l;agia~~ciag l;Dl£iC'2DW~Dtii!I S~Cl£i!.~li Identification TBE Known Ratio ofTBE to Month/Year Number Matrix Nuclide Units Reported Value (al Analytics Result Evaluation (bl Value N = Not Acceptable - reported result falls outside the ratio limits of < 0. 70 and > 1.30 September 2023 E13832 Milk Sr-89 pCi/L 49.8 71.4 0.70 w
Sr-90 pCi/L 7.28 12.8 0.57 N(1l E13833 Milk Ce-141 pCi/L 93.4 104 0.90 A
Co-58 pCi/L 58.2 65.8 0.88 A
Co-60 pCi/L 190 223 0.85 A
Cr-51 pCi/L 207 205 1.01 A
Cs-134 pCi/L 96.0 114 0.84 A
Cs-137 pCi/L 121 141 0.86 A
Fe-59 pCi/L 78.8 78.8 1.00 A
1-131 pCi/L 27.9 37.4 0.75 w
Mn-54 pCi/L 128 146 0.88 A
Zn-65 pCi/L 185 203 0.91 A
E13834 Charcoal 1-131 pCi 76.9 78.7 0.98 A
E13835 AP Ce-141 pCi 91.9 87.1 1.05 A
Co-58 pCi 58.7 55.2 1.06 A
Co-60 pCi 200 187 1.07 A
Cr-51 pCi 192 172 1.12 A
Cs-134 pCi 89.6 96 0.94 A
Cs-137 pCi 109 119 0.92 A
Fe-59 pCi 68.3 66.1 1.03 A
Mn-54 pCi 129 123 1.05 A
Zn-65 pCi 163 171 0.96 A
E13836 Soil Ce-141 pCi/g 0.228 0.184 1.24 w
Co-58 pCi/g 0.103 0.116 0.89 A
Co-60 pCi/g 0.364 0.394 0.92 A
Cr-51 pCi/g 0.371 0.362 1.02 A
Cs-134 pCi/g 0.176 0.202 0.87 A
Cs-137 pCi/g 0.285 0.315 0.90 A
Fe-59 pCi/g 0.140 0.139 1.00 A
Mn-54 pCi/g 0.237 0.259 0.92 A
Zn-65 pCi/g 0.349 0.359 0.97 A
E13837 AP Sr-89 pCi 74.6 80.2 0.93 A
Sr-90 pCi 13.9 14.4 0.96 A
(a) The Analytics known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b} Analytics evaluation based on TBE internal QC limits:
A= Acceptable-reported result falls within ratio limits of0.80-1.20 W= Acceptable with warning - reported result falls within 0. 70-0.80 or 1.20-1.30 N = Not Acceptable - reported result falls outside the ratio limits of < 0. 70 and > 1.30 (1) See NCR 23-24 B-5
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 DOE's Mixed Analyte Performance Evaluation Program (MAPEP)
Teledyne Brown Engineering Environmental Services Identification TSE Known Acceptance Month/Year Number Matrix Nuclide Units Reported (a)
Range Evaluation (b)
Value February 2023 23-MaS48 Soil Ni-63 Sq/kg 294 1130 791 - 1469 N(3) 23-MaSU48 Urine Cs-134 Sq/L 9.92 10 6.7 - 12.4 A
Cs-137 Sq/L 0.0994 (1)
A Co-57 Sq/L 9.35 8.67 6.07-11.27 A
Co-60 Sq/L 9.03 8.13 5.69 - 10.57 A
Mn-54 Sq/L 11.80 10.0 7.0-13.0 A
U-234 Sq/L 0.01 Not spiked U-238 Sq/L 0.01 Not spiked Zn-65 Sq/L 10.60 9.29 6.50 - 12.08 A
23-MaW48 Water Ni-63 Sq/L 23.1 27.3 19.1 - 35.5 A
23-RdV48 Vegetation Cs-134 Sq/sample 5.6 7.6 5.32 - 9.88 w
Cs-137 Sq/sample 0.03 (1)
A Co-57 Sq/sample 5.9 6.9 4.85 - 9.01 A
Co-60 Sq/sample 5.00 6.51 4.56 - 8.46 w
Mn-54 Sq/sample 6.08 8.03 5.62 - 10.44 w
Sr-90 Sq/sample 0.05 (1)
N(4)
Zn-65 Sq/sample 5.49 7.43 5.20- 9.66 w
August 2023 23-MaS49 Soil Fe-55 Sq/kg 346 1280 896 - 1664 N(s)
Ni-63 Sq/kg 1260 1370 959 -1781 A
23-MaW49 Water Ni-63 Sq/L 1.0 (2)
A 23-RdV49 Vegetation Cs-134 Sq/sample 3.860 4.98 3.49 - 6.47 w
Cs-137 Sq/sample 0.027 (1)
A Co-57 Sq/sample 3.88 4.24 2.97 - 5.51 A
Co-60 Sq/sample 2.37 2.79 1.95 - 3.63 A
Mn-54 Sq/sample 2.04 2.56 1.79-3.33 w
Sr-90 Sq/sample 0.96 1.17 0.82 - 1.52 A
Zn-65 Sq/sample
-0.514 (1)
A (a) The MAPEP known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation (b) DOEIMAPEP evaluation:
A= Acceptable - reported result falls within ratio limits of 0.80-1.20 W = Acceptable with warning-reported result falls within 0.70-0.80 or 1.20-1.30 N = Nol Acceptable - reported result falls outside the ratio limits of< 0. 70 and> 1.30 (1) False positive test (2) Sensitivity evaluation (3) See NCR 23-08 (4) See NCR 23-09 (5) Initial evaluation - See CAR 23-31 B-6
Dominion Energy Nuclear Connecticut, Inc.
Annual Radiological Environmental Millstone Power Station Operating Report 2023 ERA Environmental Radioactivity Cross Check Program Teledyne Brown Engineering Environmental Services MonthNear Identification Matrix Nuclide Units TBE Reported Known Acceptance Evaluation lhl Number Value Value I*>
Limits March 2023 MRAD-38 Water Am-241 pCi/L 28.1 32.1 22.0 - 41.0 A
Fe-55 pCi/L 1180 1380 811-2010 A
Pu-238 pCi/L 65.6 70.7 42.5 - 91.6 A
Pu-239 pCi/L 82.9 92.4 57.2 - 114 A
Soil Sr-90 pCi/kg 2630 2580 803 -4020 A
AP GR-A pCi/filter 69.6 76.8 40.1 -127 A
GR-B pCi/filter 36.8 32.8 19.9 - 49.6 A
April 2023 RAD-133 Water Ba-133 pCi/L 26.0 22.3 17.1 - 25.8 Nl'l Cs-134 pCi/L 72.1 77.6 63.4 - 85.4 A
Cs-137 pCi/L 62.1 63.1 56.8 - 72.2 A
Co-60 pCi/L 32.6 30.3 26.7 - 36.1 A
Zn-65 pCi/L 253 242 218 - 283 A
GR-A pCi/L 34.2 29.2 14.9 - 38.2 A
GR-8 pCi/L 64.3 60.7 41.8-67.4 A
U-Nat pCi/L 61.75 62.7 51.2 - 69.0 A
H-3 pCi/L 13,300 12700 11,100-14,000 A
Sr-89 pCi/L 67.0 61.1 49.2 - 69.0 A
Sr-90 pCi/L 36.5 36.0 26.4-41.5 A
1-131 pCi/L 24.3 28.7 23.9 - 33.6 A
September 2023 MRAD-39 Water Am-241 pCi/L 54.0 71.0 48.7 - 90.8 A
Fe-55 pCi/L 2430 2630 1550 - 3830 A
Pu-238 pCi/L 172 177 106 - 229 A
Pu-239 pCi/L 171 182 113 - 224 A
Soil Sr-90 pCi/kg 9580 6800 2120 - 10,600 A
AP GR-A pCi/filter 82.2 79.8 41.7 -131 A
GR-8 pCi/filter 54.3 42.6 25.8 -64.4 A
October 2023 RAD-135 Water Ba-133 pCi/L 86.3 92.2 73.8 - 111 A
Cs-134 pCi/L 38.4 41.2 27.9 - 54.5 A
Cs-137 pCi/L 194 199 161 - 237 A
Co-60 pCi/L 49.5 47.8 33.8 - 61.8 A
Zn-65 pCi/L 59.7 57.0 23.7 - 90.3 A
GR-A pCi/L 53.2 70.6 54.0 - 87.2 Nl'l GR-8 pCi/L 46.9 42.2 30.5 - 53.9 A
U-Nat pCi/L 51.26 51.7 45.9-57.5 A
H-3 pCi/L 20,100 22,900 19,700 - 26,100 A
Sr-89 pCi/L 51.1 38.2 25.2 - 51.2 A
Sr-90 pCi/L 31.7 35.7 30.3 - 41.1 A
1-131 pCi/L 23.5 29.7 25.8 - 33.6 Nl'l (a) The ERA known value is equal to 100% of the parameter present in the standard as determined by gravimetric and/or volumetric measurements made during standard preparation.
(b) ERA evaluation:
A = Acceptable - Reported value falls within the Acceptance Limits N = Not Acceptable - Reported value falls outside of the Acceptance Limits (1) See NCR 23-10 (2) See NCR 23-20 (3) See NCR 23-21 B-7
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station APPENDIX C ERRATUM C-1 Annual Radiological Environmental Operating Report 2023
Dominion Energy Nuclear Connecticut, Inc.
Millstone Power Station Annual Radiological Environmental Operating Report 2023 Erratum-Correction to Previously Published Annual Radiological Environmental Operating Report In the 2023 Annual Radiological Environmental Operating Report there were no correction identified to previously published Annual Radiological Environmental Operating Reports.
C-2