RS-21-059, Post-Shutdown Decommissioning Activities Report

Post-Shutdown Decommissioning Activities Report

ML21209A027
Person / Time
Site:	Dresden
Issue date:	07/28/2021
From:	Simpson P Exelon Generation Co
To:	Document Control Desk, Office of Nuclear Reactor Regulation
References
RS-21-059
Download: ML21209A027 (48)

Text

Exelon Generation 4300 Winfield Road Warrenville, IL 60555 630 65 7 2000 Office 10 CFR 50.82(a)(4)

RS-21-059 July 28, 2021 U.S. Nuclear Regulatory Commission ATTN: Document Control Desk Washington, DC 20555-0001

Subject:

Dresden Nuclear Power Station, Units 2 and 3 Renewed Facility Operating License No. DPR-19 and DPR-25 NRC Docket Nos. 50-237. 50-249. and 72-037 Dresden Nuclear Power Station, Units 2 and 3 - Post-Shutdown Decommissioning Activities Report

References:

1)

Letter from J. Bradley Fewell (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Certification of Permanent Cessation of Power Operations for Dresden Nuclear Power Station, Units 2 and 3," dated September 2, 2020 (NRC Accession No. ML2024627)

2)

Regulatory Guide 1.185, Revision 1, "Standard Format and Content for Post-Shutdown Decommissioning Activities Report," dated June 2013 (NRC Accession No. ML13140A038)

Pursuant to 10 CFR 50.82(a)(4)(i), Exelon Generation Company, LLC (Exelon) is submitting the post-shutdown decommissioning activities report (PSDAR) for Dresden Nuclear Power Station, Units 2 and 3 (DNPS-2/3). On September 2, 2020, Exelon informed the U.S. Nuclear Regulatory Commission (NRC) that DNPS-2/3 will permanently cease power operations on or before November 30, 2021 (Reference 1 ). In accordance with 10 CFR 50.82(a)(4)(i), Exelon is required to submit a PSDAR and site specific Decommissioning Cost Estimate (DCE) and in accordance with 10 CFR 50.54(bb) a Spent Fuel Management Plan (SFMP), all within two years of permanent cessation of operations.

The attachment to this letter provides the Dresden-2/3 PSDAR. The Dresden-2/3 SFMP and DCE are being submitted separately.

The PSDAR has been developed consistent with Regulatory Guide 1.185, Revision 1, "Standard Format and Content for Post-Shutdown Decommissioning Activities Report" (Reference 2). The DNPS-2/3 PSDAR includes: 1) a description of the planned decommissioning activities; 2) a schedule for their accomplishment; 3) a summary of the site-specific decommissioning cost estimate; and 4) a discussion that provides a basis for concluding that the environmental impacts associated with site-specific decommissioning will be bounded by appropriate, previously issued, environmental impact statements. The PSDAR also includes a discussion of the schedule and costs associated with the management of spent fuel and site restoration.

July 28, 2021 U.S. Nuclear Regulatory Commission Post-Shutdown Decommissioning Activities Report Page 2 In accordance with 10 CFR 50.82(a)(4 )(i), a copy of the DNPS-2/3 PSDAR is being provided to the State of Illinois by transmitting a copy of this letter and its attachment to the designated State Officials.

This letter contains no new regulatory commitments.

If you have any questions concerning this submittal, please contact John Hild itch at (267) 533-5120.

Patrick R. Simpson Sr. Manager - Licensing Exelon Generation Company, LLC

Attachment:

Dresden Nuclear Power Station, Units 2 and 3, Post-Shutdown Decommissioning Activities Report cc:

w/attachment Regional Administrator-NRC Region Ill NRC Senior Resident Inspector-Dresden Nuclear Power Station NRC Project Manager, NRR - Dresden Nuclear Power Station - Units 2 and 3 NRC Project Manager, NMSS/DUWP/RDB - Dresden Nuclear Power Station, Unit 1 Illinois Emergency Management Agency - Division of Nuclear Safety

Attachment Dresden Nuclear Power Station, Units 2 and 3 Post-Shutdown Decommissioning Activities Report

POST-SHUTDOWN DECOMMISSIONING ACTIVITIES REPORT (PSDAR)

Dresden Nuclear Power Station, Units 2 and 3 July 2021

Contents Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report ACRONYMS................................................................................................................................. 1 1 INTRODUCTION AND

SUMMARY

......................................................................................... 3 1.1 Introduction..................................................................................................................... 3 1.2 GENERAL DESCRIPTION............................................................................................. 4 1.3 Summary of Decommissioning Alternatives................................................................... 5 2 DESCRIPTION OF PLANNED DECOMMISSIONING ACTIVITIES........................................ 7 2.1 Discussion of Decommissioning Activities.................................................................... 10 2.1.1 Preparations for Decontamination and Dismantlement.................................. 10 2.1.2 Decommissioning Operations (Active Decontamination and Dismantlement)............................................................................................... 12 2.1.3 ISFSI Operations Period................................................................................. 14 2.1.4 Site Restoration Period................................................................................... 14 2.2 General Decommissioning Considerations................................................................... 15 2.2.1 Major Decommissioning Activities.................................................................. 15 2.2.2 Decontamination and Dismantlement Activities.............................................. 15 2.2.3 Radioactive Waste Management.................................................................... 16 2.2.4 Removal of Mixed Wastes.............................................................................. 16 2.2. 5 Site Characterization...................................................................................... 16 2.2.6 Groundwater Protection and Radiological Decommissioning Records Program.......................................................................................................... 17 2.2.7 Changes to Management and Staffing........................................................... 17 3 SCHEDULE OF PLANNED DECOMMISSIONING ACTIVITIES.......................................... 18 4 ESTIMATE OF EXPECTED DECOMMISSIONING AND SPENT FUEL MANAGEMENT COSTS........................................................................................................................................ 19 4.1 Cost Estimate Adjustments........................................................................................... 20 4.2 Means of Adjusting Cost Estimates and Associated Funding Levels........................... 20 5 ENVIRONMENTAL IMPACTS............................................................................................... 21 5.1 Environmental Impact of DNPS-2/3 Decommissioning................................................. 21 5.1.1 Onsite I Offsite Land Use................................................................................ 22 Page i of ii

5.1.2 5.1.3 5.1.4 5.1.5 5.1.6 5.1.7 5.1.8 5.1.9 5.1.10 5.1.11 5.1.12 5.1.13 Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Water Use....................................................................................................... 22 Water Quality.................................................................................................. 23 Air Quality....................................................................................................... 24 Aquatic Ecology.............................................................................................. 25 Terrestrial Ecology.......................................................................................... 26 Threatened and Endangered Species............................................................ 27 Radiological.................................................................................................... 31 Radiological Accidents.................................................................................... 32 Occupational Issues....................................................................................... 33 Cost................................................................................................................ 33 Socioeconomics.............................................................................................. 33 Environmental Justice..................................................................................... 34 5.1.14 Cultural, Historical, and Archaeological Resources........................................ 34 5.1.15 Aesthetic Issues.............................................................................................. 36 5.1.16 Noise............................................................................................................... 37 5.1.17 Transportation................................................................................................. 37 5.1.18 Irreversible and Irretrievable Commitment of Resources............................... 39 5.2 Environmental Impacts of License Termination - NUREG-1496.................................. 39 5.3 Discussion of Decommissioning in the SEIS................................................................ 39 5.4 Additional Considerations............................................................................................. 39 5.5 Conclusions.................................................................................................................. 40 6 REFERENCES....................................................................................................................... 41 List of Tables Table 2-1: Decommissioning Schedule and Plant Status Summary.......................................... 8 Table 2-2: Decommissioning Cost Summary.............................................................................. 9 Table 5-1 : Protected Species Potentially Occurring in DNPS Vicinity Through 2020............... 27 Table 5-2: Estimated Radioactive Waste Associated with DNPS-2/3 Decommissioning......... 38 Page ii of ii

AIF ALA RA BMP BWR CFR CWA D&D DCE DSAR DNPS DNPS-1 DNPS-2/3 DTF DOE EcoCAT EPU Exelon FES FP FSAR FSS GEIS GTCC HVAC IAC IAS IDNR IEPA IL-SH PO Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report ACRONYMS Atomic Industrial Forum As Low as Reasonably Achievable Best Management Practices Boiling Water Reactor Code of Federal Regulations Clean Water Act Decontamination and Dismantlement Decommissioning Cost Estimate Defueled Safety Analysis Report [the UFSAR is commonly referred to as the DSAR during decommissioning]

Dresden Nuclear Power Station Dresden Nuclear Power Station, Unit 1 Dresden Nuclear Power Station, Units 2 and 3 Decommissioning Trust Fund Department of Energy Ecological Compliance Assessment Tool (Illinois Department of Natural Resources]

Extended Power Uprate Exelon Generation Company, LLC Final Environmental Statement Related to the Operation of Dresden Nuclear Power Station, Units 2 and 3 Fire Protection Final Safety Analysis Report Final Status Survey Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities (NUREG-0586)

Greater than Class C Heating Ventilating Air Conditioning Illinois Administrative Code Illinois Archaeological Survey Illinois Department of Natural Resources Illinois Environmental Protection Agency Illinois State Historic Preservation Office Page 1 of 42

IPaC ISFSI LLC LLRW LTP MARSSIM MWt NAICS NEI NEPA NESP NPDES NPS NRC NRHP ODCM OSHA PS DAR REMP SEIS SFP SS Cs UFSAR USFWS Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Information for Planning and Consultation

[United States Fish and Wildlife Service}

Independent Spent Fuel Storage Installation Limited Liability Company Low-Level Radioactive Waste License Termination Plan Multi-Agency Radiation Survey and Site Investigation Manual Megawatt-thermal North American Industry Classification System Nuclear Energy Institute National Environmental Protection Act National Environmental Studies Project National Pollutant Discharge Elimination System United States National Park Service United States Nuclear Regulatory Commission National Register of Historic Places Offsite Dose Calculation Manual Occupational Safety and Health Administration Post-Shutdown Decommissioning Activities Report Radiological Environmental Monitoring Program Generic Environmental Impact Statement for License Renewal of Nuclear Plants (NUREG-1437), Supplement 17, "Regarding Dresden Nuclear Power Station, Units 2 and 3" Spent Fuel Pool Structures, Systems and Components Updated Final Safety Analysis Report United States Fish and Wildlife Service Page 2 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 1

INTRODUCTION AND

1.1 INTRODUCTION

In accordance with the requirements of Title 10 of the Code of Federal Regulations (CFR), Part 50, Section 50.82, "Termination of license," paragraph (a)(4)(i), [10 CFR 50.82(a)(4)(i)] this report constitutes the Post-Shutdown Decommissioning Activities Report (PSDAR) for the Dresden Nuclear Power Station, Units 2 and 3 (DNPS-2/3). This PSDAR addresses the following:

1.

A description of the planned decommissioning activities along with a schedule for their accomplishment.

2.

A discussion that provides the reasons for concluding that the environmental impacts associated with site-specific decommissioning activities will be bounded by appropriate previously issued environmental impact statements.

3.

A summary of the site-specific decommissioning cost estimate (DCE), including the projected cost of managing spent fuel and the post-decommissioning site restoration cost. The site specific DCE will be submitted to the NRC under a separate cover letter.

The PSDAR has been developed consistent with Regulatory Guide 1.185, "Standard Format and Content for Post-Shutdown Decommissioning Activities Report," (Reference 1 ). This report is based on currently available information and the plans discussed herein may be modified as additional information becomes available or conditions change. As required by 10 CFR 50.82(a)(7), Exelon Generation Company, LLC (Exelon) will notify the Nuclear Regulatory Commission (NRC) in writing, with copies sent to the State of Illinois, before performing any decommissioning activity inconsistent with, or making any significant schedule change from, those actions and schedules described in the PSDAR, including changes that significantly increase the decommissioning cost. Additionally, to comply with its continuing obligation under 10 CFR 50.82(a)(6)(ii) to assure that any decommissioning activity that would result in significant environmental impacts would be previously reviewed by the NRC, Exelon will provide the NRC with updates of site-specific impact assessments after decommissioning activities that could cause such effects have been finally determined and scheduled.

A brief history of the major milestones related to DNPS-2/3 construction and operational history is as follows:

Unit 2 Unit 3 Construction Permit Issued January 10, 1966 October 14, 1966 Provisional Operating License December 22, 1969 Operating License Issued February 20, 1991 January 12, 1971 Commercial Operation June 1970 November 1971 Extended Power Uprate (EPU)a December 21, 2001 December 21, 2001 Original License Expiration December 22, 2009 January 12, 2011 Renewed License Expiration December 22, 2029 January 12, 2031 a Amendments 191 and 185 for EPU issued.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report By letter dated September 2, 2020 (Reference 2), Exelon provided formal notification to the NRC that it intended to permanently cease power operations of DNPS-2/3 on or before November 30, 2021, in accordance with 10 CFR 50.82(a)(1 )(i) and 10 CFR 50.4(b)(8). Upon docketing of the certifications required by CFR 50.82(a)(1 )(i) and 10 CFR 50.82(a)(1 )(ii),

pursuant to 10 CFR 50.82(a)(2), the 10 CFR 50 licenses for DNPS-2/3 will no longer authorize operation of the reactors or emplacement or retention of fuel in the reactor vessels.

Pursuant to 10 CFR 50.51(b), "Continuation of license," the license for a facility that has permanently ceased operations continues in effect beyond the expiration date to authorize ownership and possession of the utilization facility until the NRC notifies the licensee in writing that the license has been terminated.

During the period that the license remains in effect, 10 CFR 50.51(b) requires that the licensee:

(1) Takes actions necessary to decommission and decontaminate the facility and continue to maintain the facility, including, where applicable, the storage, control, and maintenance of the spent fuel, in a safe condition, and (2) Conducts activities in accordance with all other restrictions applicable to the facility in accordance with NRC regulations and the 10 CFR Part 50 license for the facility.

10 CFR 50.82(a)(9) states that all power reactor licensees must submit an application for termination of the license at least two years prior to the license termination date and that the application must be accompanied or preceded by a license termination plan to be submitted for NRC approval.

1.2 GENERAL DESCRIPTION The DNPS site includes three reactors that were initially constructed and operated by Commonwealth Edison. The DNPS site is located in northeast Illinois, in Grundy County. The nearest town is Channahon, approximately 3 miles northeast. The site is approximately 8 miles east of Morris, Illinois, and 50 miles southwest of downtown Chicago. The DNPS site includes DNPS Unit 1 (DNPS-1 ), and DNPS Units 2 and 3 (DNPS-2/3). The DNPS site consists of approximately 2,500 acres owned by Exelon with an additional 17 acres of river frontage leased from the State of Illinois. The site includes the reactors and supporting structures on the north end (approximately 953 acres) and a large cooling pond (approximately 1,275 acres of the total 2,500 acres) on the south end. The Unit 1 structures are intermingled with those of Units 2 and 3. Unit 1 was shutdown October 31, 1978 and was never returned to service. In October 1984 a decision was made to decommission Unit 1. DNPS-1 major structures are still present and intact; however, the decommissioning of Unit 1 is an independent action addressed in a separate PSDAR (Reference 3). Unit 2 is located on the site directly west of and adjacent to Unit 1. The location of Unit 3 is directly west of and adjacent to Unit 2. At this location, the units are situated approximately 0.5 miles from the south boundary of the site.

DNPS-2/3 are General Electric Boiling Water Reactors (BWRs), owned and operated by Exelon.

DNPS-2/3 are licensed to generate 2957 megawatts-thermal (MWt). DNPS-2/3 were each originally analyzed for a "reference design" thermal output of 2255 MWt and designed to permit ultimate operation at power levels of about 2600 MWt. Analyses and modifications performed as part of the extended power uprate (EPU) support operation of the units at 2957 MWt. The reactors and supporting infrastructure are located at the north end of the site adjacent to the Kankakee River (i.e., the eastern side of the site). Other supporting structures, including two Page 4 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report independent spent fuel storage installation (ISFSI) pads, are within the protected area. Other structures associated with the site include a radwaste storage mausoleum, two switchyards, training building, parking lots, sewage treatment plant, mechanical draft cooling towers, and site roads. The tallest structures onsite are the two ventilation exhaust stacks, one for DNPS-1 and the other for DNPS-2/3. Two man-made canals ("hot" and "cold" canals), approximately 2 miles in length, connect the DNPS-2/3 intake and discharge canals to the cooling pond. The intake canal for DNPS-2/3 extends from the Kankakee River east of the reactors. The discharge canals, one for DNPS-2/3 and another for DNPS-1, extend to the Illinois River north of the plant.

1.3

SUMMARY

OF DECOMMISSIONING ALTERNATIVES The NRC has evaluated the environmental impacts of three general methods for decommissioning power reactor facilities in NUREG-0586, "Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities: Supplement 1, Regarding the Decommissioning of Nuclear Power Reactors" (GEIS) (Reference 4). The three general methods evaluated are summarized as follows:

DEGON: The equipment, structures and portions of the facility and site that contain radioactive contaminants are promptly removed or decontaminated to a level that permits termination of the license shortly after cessation of operations.

SAFSTOR: After the plant is shut down and defueled, the facility is placed in a safe, stable condition and maintained in that state (safe storage). The facility is decontaminated and dismantled at the end of the storage period to levels that permit license termination. During SAFSTOR, a facility is left intact [or may be partially dismantled], but the fuel is removed from the reactor vessel and radioactive liquids are drained from systems and components and then processed. Radioactive decay occurs during the SAFSTOR period, thereby lowering the level of contamination and radioactivity that must be disposed of during decontamination and dismantlement.

ENTOMB: Radioactive structures, systems, and components (SSCs) are encased in a structurally long-lived substance, such as concrete. The entombed structure is appropriately maintained, and continued surveillance is carried out until the radioactivity decays to a level that permits termination of the license.

The decommissioning approach that has been selected by Exelon for DNPS-2/3 is a Shortened SAFSTOR method.a The primary objectives of the DNPS-2/3 decommissioning project is to remove the facility from service, reduce residual radioactivity to levels permitting unrestricted release, restore the site, perform this work safely, and complete the work in a cost-effective manner. The selection of a preferred decommissioning method is influenced by a number of factors at the time of plant shutdown. These factors include the cost of each decommissioning method, minimization of occupational radiation exposure, availability of a Department of Energy (DOE) high-level waste (spent fuel) repository or a consolidated interim storage facility, regulatory requirements, and public concerns. In addition, 10 CFR 50.82(a)(3) requires decommissioning to be completed within 60 years of permanent cessation of operations.

a As discussed in Chapter 2, Exelon is using a Shortened SAFSTOR scenario where active decommissioning is deferred approximately 7 years after permanent shutdown.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Currently, Exelon plans to store the spent fuel in the Spent Fuel Pools (SFPs) (wet storage) until it has decayed sufficiently that it can be loaded into spent fuel casks and transferred to the ISFSI for dry storage, where it will be maintained until it can be transported offsite to a repository. After the safe storage period, the facility will be decontaminated and dismantled to levels that allow unrestricted radiological release of the property. In accordance with 10 CFR 50.82(a)(9), a license termination plan will be developed and submitted for NRC approval at least two years prior to termination of the license.

The decommissioning approach for DNPS-2/3 is described in the following sections.

Section 2.0 describes the planned decommissioning activities and the general timing of their implementation.

Section 3.0 describes the overall decommissioning schedule, including the spent fuel management activities.

Section 4.0 provides an analysis of expected decommissioning costs, including the costs associated with spent fuel management and site restoration.

Section 5.0 describes the basis for concluding that the environmental impacts associated with decommissioning DNPS-2/3 are bounded by appropriate, previously issued environmental impact statements.

Section 6.0 is a list of references.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 2

DESCRIPTION OF PLANNED DECOMMISSIONING ACTIVITIES For the purposes of evaluating the PSDAR activities and preparing the DCE, Exelon evaluated the following decommissioning scenarios which are similar to the DEGON and SAFSTOR methods broadly described in Section 1.3 of this report:

DECON - spent fuel is transferred to the ISFSI shortly after shutdown and decommissioning and dismantlement begins shortly after that.

Shortened SAFSTOR - the spent fuel is transferred to the ISFSI and decommissioning is deferred approximately 7 years after permanent shutdown.

SAFSTOR - the spent fuel is transferred to the ISFSI and the plant facility is left intact until the decommissioning starts sometime in the future (dormancy phase), with structures maintained in a sound condition. Decommissioning commences such that license termination is completed within the required 60-years.

Exelon is currently planning to decommission DNPS-2/3 using a shortened SAFSTOR period as described above. After DNPS Units 2 and 3 are shutdown and defueled, they will be placed in a safe, stable condition and maintained in that state (safe storage) until decontamination and dismantlement begin.

The initial decommissioning transition activities to be performed after plant shutdown will entail preparing the plant for a short dormancy period. This will include defueling the reactors and transferring the spent fuel into the SFPs, draining fluids from and de-energizing systems that are no longer required, reconfiguring the electrical distribution, ventilation, heating, and fire protection systems, and minor deconstruction activities. Systems temporarily needed for continued operation of the SFPs may be reconfigured for operational efficiency.

Following the initial decommissioning transition activities, DNPS-2/3 will primarily be left intact for approximately 7 years until active Decontamination and Dismantlement (D&D) begins.

During this period, equipment abandonment and some minor dismantlement activities may take place and spent fuel will be transferred from the SFPs to the ISFSI.

Spent fuel will remain in the SFPs until it meets the criteria for transfer to dry storage in the ISFSI. Dresden will begin the project to transfer spent fuel to an ISFSI pad in 2021. All spent fuel is expected to be transferred to the ISFSI by 2026. During an approximate 2-year period after all fuel has been transferred to the ISFSI, some additional abandonments will occur, including draining the SFPs and draining and de-energizing the SFPs supporting systems.

During this same 2-year period, planning and preparations for active D&D will occur.

The spent fuel will be stored in the ISFSI until it is transferred to the DOE. DNPS-2/3 will incur costs associated with the requirements to maintain and store spent fuel onsite (spent fuel management costs) until the DOE is assumed to take possession of the spent fuel in 2051.

Active decontamination and D&D activities for DNPS-2/3 are assumed to begin in 2029. The planned schedule enables the DNPS-2/3 licenses to be terminated well within 60 years after permanent cessation of operations. Following completion of the D&D activities, the NRC licenses will be terminated. Although Exelon is not obligated to restore the site to a greenfield condition, for purposes of this PSDAR, Exelon conservatively has made an assumption that includes restoration of the site to a greenfield condition, but that conservative assumption is not Page 7 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report a commitment to do so. Site restoration is anticipated to be performed to place the site in a condition acceptable for beneficial reuse. The current decommissioning cost estimate assumes that remaining structures will be demolished to three (3) feet below grade and that the excavations will be backfilled with suitable material and erosion controls emplaced.

Exelon will complete radiological decommissioning and spent fuel management as required by NRC regulations and will determine the extent of site restoration at a later date.

Decommissioning activities will be performed in accordance with written, reviewed, and approved site procedures. There are no identified or anticipated decommissioning activities that are unique to the DNPS-2/3 site.

Compliance with applicable regulatory programs will be maintained throughout the decommissioning process to ensure the health and safety of workers, the public, and the environment. Radiological monitoring programs will be conducted in accordance with the facility's revised Technical Specifications, Renewed Facility Licenses, Updated Final Safety Analysis Report/Defueled Safety Analysis Report (UFSAR/DSAR), Radiological Environmental Monitoring Program (REMP), and the Offsite Dose Calculation Manual (ODCM). Non-radiological environmental monitoring programs will be conducted in accordance with applicable regulatory requirements and permits.

Tables 2.1 and 2.2 below summarizes the schedule I plant status and costs for decommissioning DNPS-2/3. The major decommissioning activities and general sequence are discussed in more detail in the sections that follow.

Table 2-1:

Decommissioning Schedule and Plant Status Summary Plant Status I Decommissioning Approximate Start End Duration Activities (years)

Pre-Shutdown Pre-Shutdown Planning Jan 2021 Nov 2021 0.9 Preparations for D&D Plant Shutdown I Defueling Outage Nov 2021 Dec 2021 0.1 Fuel to the ISFSI Pads Dec 2021a Oct 2026 4.9 System Abandonment/Preparations for Nov 2026 Dec 2028 2.2 D&D [Dormancy]

Decommissioning Operations Large Component Removal Jan 2029 Aug 2032 3.6 Plant Systems Removal and Building Aug 2032 Aug 2034 2.0 Decontamination License Termination Aug 2034 May 2035 0.7 a Dresden will begin the project to transfer spent fuel to an ISFSI pad in 2021.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Site Restoration[aJ May 2035 Nov 2037 ISFSI Operation Operation (Post License Termination)

May 2035 Sept 2046 Fuel Shipping Oct2046 Dec 2051 Decontamination and License Jan 2052 Sept 2052 Termination ISFSI Site Restoration Sept2052 Nov 2052 Total from Shutdown to Completion of License Termination Table 2-2:

Decommissioning Cost Summary (December 31, 2020, dollars - thousands)

Decommissioning Periods Radiological Spent Fuel Decommissioning Management Pre-Shutdown Pre-Shutdown Planning 11,390 Preparations for D&D Plant Shutdown I Defueling Outage 520 Fuel to the ISFSI Pads 338,936 296,533 System Abandonment/Preparations for 88,889 6,554 D&D [Dormancy]

Decommissioning Operations Large Component Removal 580,601 11,792 Plant Systems Removal and Building 364,772 6,530 Decontamination License Termination 25,407 2,448 Site Restoration[bJ ISFSI Operations Operation (Post License Termination) 59,219 Fuel Shipping 33, 143 52,880 Decontamination and License 13,327 Termination ISFSI Site Restoration Total[cJ 1,456,985 435,956 Site Restoration coincides with the start of ISFSI operation, after License Termination Site Restoration from May 2035 to Nov 2037 Columns may not add due to rounding Page 9 of 42 2.5 11.4 5.2 0.7 0.2 30.8 Site Restoration 293 290 1,364 8, 181 111, 162 302 6,185 127,777

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 2.1 DISCUSSION OF DECOMMISSIONING ACTIVITIES The following narrative describes the basic activities associated with decommissioning DNPS-2/3. The site-specific DCE, as further discussed in Section 4, is divided into phases or periods based upon major milestones within the project or significant changes in the annual projected expenditures. The following sub-sections correspond to the major decommissioning periods within the estimate.

2.1.1 Preparations for Decontamination and Dismantlement The NRC defines SAFSTOR as, "A method of decommissioning in which a nuclear facility is placed and maintained in a condition that allows the facility to be safely stored and subsequently decontaminated (deferred decontamination) to levels that permit release for unrestricted use."

During this period, the facility is left intact, with most structures maintained in a stable condition; some outbuildings not related to power production will be removed. Systems that are not required to support the spent fuel, HVAC, Emergency Plan, or site security are drained, de-energized, and secured. Some cleaning I removal of loose contamination and/or fixation, and sealing of remaining contamination may be performed. Access to contaminated areas is maintained secure to provide controlled access for inspection and maintenance.

A 24-hour/7-day per week security force will be present as long as fuel remains on site.

Security during the preparations for decontamination and dismantlement period will be conducted primarily to safeguard the spent fuel stored on site and prevent unauthorized entry.

Security barriers, sensors, alarms, and other surveillance equipment will be maintained as required to provide security.

An environmental surveillance program will be carried out to monitor for radioactive material in the environment. Appropriate procedures will be established and initiated for potential releases that exceed prescribed limits. The environmental surveillance program will consist of a version of the program in effect during normal plant operations that will be modified to reflect the plant's conditions and risks at the time.

Prior to the commencement of the Decommissioning Operations, preparations will be undertaken to prepare for active decommissioning. Preparations include engineering and planning activities associated with active decommissioning, site characterization, and the transition to a Decommissioning Operations management organization. This would likely include the development of active decommissioning work plans, specifications, and procedures.

The process of preparing the facility for decontamination and dismantlement will include, but is not limited to, the following activities:

Creation of an organizational structure to support the decommissioning plan and evolving emergency planning and site security requirements.

Revision of Technical Specifications, plans, and operating procedures appropriate to the decommissioning activities, conditions, and requirements.

Characterization of the facility and major components, as may be necessary, to plan and prepare for the Decommissioning Operations period.

Management of the SFPs and reconfiguring fuel pool support systems so that draining and de-energizing may commence in other areas of the plant.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Deactivation (de-energizing and or draining) of systems that are no longer required.

Processing and disposal of water and water filter and treatment media (resins) as necessary.

Transfer of spent fuel from the SFPs to the ISFSI. After all the spent fuel is removed from the SFPs, the SFPs and supporting systems may be drained and de-energized.

Expansion of the ISFSI area and acquisition of the dry fuel storage casks for off-load of the SFPs.

Removal of selected structures to provide for efficient monitoring of the ISFSls and to facilitate Decommissioning Operations.

Disposition of incidental waste that may be present and ready to ship prior to the start of the Decommissioning Operations period, such as, excess tools and equipment and waste produced while deactivating systems and preparing the facility for the Decommissioning Operations period.

Reconfiguration of power, lighting, heating, ventilation, fire protection, and any other services needed to support long-term storage and periodic plant surveillance and maintenance.

Stabilization by fixing or removing loose incidental surface contamination to facilitate future building access and plant maintenance. Decontamination of high-dose areas is not anticipated prior to the Decommissioning Operations period.

Performance of interim radiation surveys of the plant, posting radiological control signs and establishing access requirements, where appropriate.

Maintenance of appropriate barriers for contaminated and radiation areas.

Reconfiguration of security boundaries and surveillance systems, as needed to support efficiency following permanent plant shutdown.

The following is a general discussion of the planned reconfiguration expected after plant shutdown.

2. 1. 1. 1 Electrical Svstems The electrical systems will undergo a series of reconfigurations between shutdown and the time all spent fuel has been transferred to the ISFSI. The reconfigurations will be performed to reduce operating and maintenance expenses, while maintaining adequate power for station loads, and backup power for SFP-related systems and critical security equipment.

2. 1. 1. 2 Mechanical Systems Following shutdown, as applicable, fluid filled systems will be drained and abandoned, or placed in lay-up, based on an evaluation of system category, functionality, and plant configuration. The plant configuration and functionality of each system within the plant configuration as it evolves will determine when a system can be drained and abandoned.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 2.1.1.3 Ventilation and Heating Systems Ventilation systems will be reconfigured, maintained, or abandoned to support decommissioning activities and support freeze protection inside of structures. Systems requiring support are Fuel Pool Cooling SSCs, Fire Protection, SSCs inside the Radiological Controlled Areas, Security SSCs, and Dry Fuel SSCs. The heating steam system will continue to operate until the station has implemented an alternative.

2.1.1.4 Fire Protection Svstems Fire Protection (FP) systems will be reconfigured based on a fire hazards analysis. The fire hazards analysis provides a comprehensive evaluation of the facility's fire hazards, the fire protection capability relative to the identified hazards, and the ability to protect spent fuel and other radioactive materials from potential fire induced releases. The fire hazards analysis will be reevaluated and revised as necessary to reflect the unique or different fire protection issues and strategies associated with decommissioning. It is expected that as the plant's systems are drained and the combustible loading footprint shrinks, the FP requirements will be reduced.

2. 1. 1. 5 Maintenance of Svstems Critical to Decommissioning There are no mechanical systems that will be critical to the final decommissioning process. As such, mechanical systems will be abandoned after all spent fuel has been transferred to the ISFSI. The site power distribution system will be abandoned with the possible exception of motor control centers that are required to support ventilation and lighting.

The organization responsible for the final dismantlement will be expected to establish temporary services, including electrical and cranes.

2.1.2 Decommissioning Operations (Active Decontamination and Dismantlement)

Following the preparations for decommissioning, physical decommissioning activities will take place. This includes the removal and disposal of contaminated and activated components and structures, leading to the termination of the 10 CFR 50 operating licenses. Although much of the radioactivity will decrease during the dormancy period due to decay of 6°Co and other short-lived radionuclides, the internal components of the reactor vessels will still exhibit radiation dose rates that will likely require remote sectioning underwater due to the presence of long-lived radionuclides such as 94Nb, 59Ni, and 63Ni. Portions of the biological shield walls may also be radioactive due to the presence of activated trace elements with longer half-lives (such as 152Eu and 154Eu). It is assumed that radioactive contamination on SSC surfaces will not have decayed to levels that will permit unrestricted release. These surfaces will be surveyed, and items dispositioned in accordance with the license termination release criteria.

Significant decommissioning activities in this phase include:

Reconfiguration and modification of site structures and facilities, as needed, to support decommissioning operations. Modifications may also be required to the reactor or other buildings to facilitate movement of equipment and materials, support the segmentation of the reactor vessels and reactor vessel internals, and for large component removal.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Design and fabrication of temporary and longer-term shielding to support removal and transportation activities, construction of contamination control envelopes, and the procurement of specialty tooling.

Procurement or leasing of shipping cask, cask liners, and industrial packages for the disposition of low-level radioactive waste.

Disposition of legacy waste, including retired steam dryers.

Decontamination of components and piping systems, as required, to control worker exposure to levels as low as reasonably achievable.

Removal of piping and components no longer essential to support decommissioning operations.

Removal of reactor heads and segmentation as necessary.

Removal and segmentation of the steam dryers, steam separators, and top guides.

Segmentation will maximize the loading of the shielded transport casks, i.e., by weight and activity. These operations are expected to be conducted underwater using remotely operated tooling and contamination controls.

Disassembly and segmentation of the remaining reactor internals, including the core materials left above the core support guide, core shroud, fuel support castings, core support guide, control rod drive guide tubes, and control rod blades. Some material is expected to exceed Class C disposal requirements. As such, the segments will be packaged in modified fuel storage canisters for future geologic disposal.

Segmentation of the reactor vessels as necessary. A shielded platform will be installed for cutting operations, which will be performed using remotely operated equipment within a contamination control envelope.

Removal of steel plate from the drywells, torus', reactor cavity and SFPs, and disposing of the activated and I or contaminated sections as radioactive waste.

Removal of the activated portions of the concrete biological shields and accessible contaminated concrete surfaces.

Removal of the recirculation piping and pumps for material recovery and controlled disposal.

Surface soil, sub-surface media and groundwater will meet the unrestricted use criteria in 10 CFR 20.1402.

Underground piping (or similar items) and associated soil will be removed as necessary to meet license termination criteria.

At least two years prior to the anticipated date of each unit's license termination, a License Termination Plan (L TP) will be submitted to the NRC. That plan will include: a site characterization, description of the remaining dismantling I removal activities, plans for remediation of remaining radioactive materials, developed site-specific Derived Concentration Guideline Levels, methodology and criteria for the Final Status (radiation) Survey (FSS),

designation of the end use of the site, an updated cost estimate to complete the decommissioning, and associated environmental concerns.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report The FSS plan will identify the radiological surveys to be performed once the decontamination activities are completed, and it will be developed using the guidance provided in NUREG-1575, "Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM)" (Reference 5). As stated in the abstract to the MARSSIM, "The MARSSIM provides information on planning, conducting, evaluating, and documenting building and surface soil final status radiological surveys for demonstrating compliance with dose or risk-based regulations or standards." The MARSSIM uses the Data Quality Objective I Analysis processes tool for data collection activities and provides a basis for balancing decision uncertainty with available resources. This document incorporates statistical approaches to survey design and data evaluation. It also identifies commercially available instrumentation and procedures for conducting radiological surveys. Use of this guidance ensures that the surveys are conducted in a manner that provides a high degree of confidence that applicable NRG criteria are satisfied. Once the FSS is complete, the results will be submitted to the NRG, along with a request for termination of the NRC licenses.

Exelon may request release of unaffected portions of the site on a partial site release basis, as they become available, before all site decommissioning work has been completed.

2.1.3 ISFSI Operations Period The dates of ISFSI only operation are provided in Table 2.1. These dates are scheduled to occur after the main power block Decommissioning Operations period has been completed.

The ISFSI will continue to be operated until all the stored casks can be shipped offsite. For planning purposes, Exelon's Spent Fuel Management Plan reflects the current assumption that the stored casks will be shipped to the DOE between October 2046 and December 2051. It is acknowledged that the most expeditious means of removing casks from the site will be undertaken once the DOE begins receiving casks. The ISFSI will be decommissioned once all casks have been removed.

2.1.4 Site Restoration Period Site restoration is assumed to begin after license termination, at the licensee's discretion. Since the power block area is assumed to be released prior to the ISFSI area at Dresden, site restoration for the power block area is proposed to begin once a partial license termination for that area is received, and then subsequentially the ISFSI area will be restored after full license termination. Exelon currently assumes that remaining structures will be removed to a nominal depth of three feet below the surrounding grade level. Affected area(s) would then be backfilled with suitable fill materials, graded, and appropriate erosion controls established.

Non-contaminated concrete remaining after the demolition activities may be used for backfilling subsurface voids or may be transported to an offsite area for appropriate disposal as construction debris.

As mentioned previously, Exelon is not obligated to restore the site to a greenfield condition.

Exelon conservatively assumes restoration of the site to a greenfield condition; however, this conservative assumption is not a commitment to do so. Exelon will complete radiological decommissioning and spent fuel management and will determine the extent of site restoration at a later date.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 2.2 GENERAL DECOMMISSIONING CONSIDERATIONS 2.2.1 Major Decommissioning Activities As defined in 10 CFR 50.2, "definitions," a "major decommissioning activity" is "any activity that results in permanent removal of major radioactive components, permanently modifies the structure of the containment, or results in dismantling components for shipment containing greater than class C waste in accordance with§ 61.55 of this chapter." The following discussion provides a summary of the major decommissioning activities currently planned for decommissioning DNPS-2/3. These activities are envisioned to occur in the Dismantling and Decontamination Period. The schedule may be modified as conditions dictate.

Prior to starting a major decommissioning activity, the affected components will be surveyed and decontaminated, as required, in order to minimize worker exposure, and a plan will be developed for the activity. Shipping casks and other equipment necessary to conduct major decommissioning activities will be procured.

The following approach will be similar for both Dresden Unit 2 and Unit 3.

The initial major decommissioning activity inside the reactor building will be the removal, packaging, and disposal of systems and components attached to the reactors, to provide access and allow it to be removed.

The reactor vessels internals will be removed from the reactor vessels and segmented, if necessary, for packaging, transport, and disposal, or to separate greater than Class C (GTCC) waste. Internals classified as GTCC waste will be segmented and packaged into containers similar to spent fuel canisters for storage at the ISFSI and/or transfer to the DOE. Removal of the reactor vessels will follow the removal of the reactor vessels internals. Industry experience indicates that there may be several options available for the removal and disposal of the reactor vessels (i.e., segmentation or disposal as an intact package). The viability of these options will be analyzed as a part of future planning and preparation activities. If the reactor vessels are segmented, it is likely that the work would be performed remotely using a contamination control envelope.

2. 2. 1. 1 Other Decommissioning Activities Other major decommissioning activities that would be conducted include the removal and disposal of the turbines, condensers, reactor coolant piping, reactor recirculation pumps and motors, SFPs support equipment, and neutron activated I contaminated concrete or metals.

In addition to the reactors and large components discussed above, all other plant components will be removed from the Reactor, Turbine, and associated support buildings (including the long-term steam dryer storage building), radiologically surveyed and dispositioned appropriately.

2.2.2 Decontamination and Dismantlement Activities The overall objective of D&D is to ensure that radioactively contaminated or activated materials will be removed from the site to allow the site to be released for unrestricted use. This is achieved in part by radioactive decay during the SAFSTOR period which will reduce the quantity of radioactive material that must be disposed of during decontamination and dismantlement.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report The disposition of remaining radioactive materials will be accomplished by the decontamination and I or dismantlement of contaminated structures. This may be accomplished by decontamination in place, off-site processing of the materials, or direct disposal of the materials as radioactive waste. A combination of these methods may be utilized. The methods chosen will be those deemed most appropriate for the particular circumstances.

Low-level radioactive waste (LLRW) will be managed in accordance with approved procedures and commercial disposal facility requirements. This includes characterizing contaminated materials, packaging, transporting and disposal at a licensed LLRW disposal facility.

2.2.3 Radioactive Waste Management A major component of the decommissioning work scope for DNPS-2/3 is the packaging, transportation and disposing of primarily contaminated I activated equipment, piping, concrete, and in some cases soil. A waste management plan will be developed to incorporate the most cost-effective disposal strategy, consistent with regulatory requirements and disposal I processing options for each waste type at the time of the D&D activities. Decommissioning wastes from DNPS-2/3 may be disposed of at the Waste Control Specialists, LLC facility in Andrews, Texas and the EnergySo/utions, Inc. facility in Clive, Utah. If other licensed disposal facilities become available in the future, Exelon may elect to use them. Some low-level radioactive waste may also be shipped for processing to the EnergySo/utions Bear Creek Processing Facility near Oak Ridge, Tennessee. Radioactive wastes from DNPS-2/3 will be transported by licensed transporters. The waste management plan will be based on the evaluation of available methods and strategies for processing, packaging, and transporting radioactive waste in conjunction with the available disposal facility options and associated waste acceptance criteria.

2.2.4 Removal of Mixed Wastes If mixed wastes are generated, they will be managed in accordance with applicable federal and state regulations and transported by authorized licensed waste transporters to authorized licensed waste management facilities. If technology, resources, and approved processes are available, these processes will be evaluated to render the mixed waste non-hazardous.

2.2.5 Site Characterization During the decommissioning process, site characterization will be performed in which radiological, regulated, and hazardous wastes will be identified, categorized, and quantified.

Surveys will be conducted to establish hazardous and radioactive material contamination levels and radiation levels throughout the site. This information will be used in developing procedures, surveys, and sampling plans to ensure that hazardous, regulated, and radiologically contaminated areas are remediated and to ensure that worker exposure is controlled. As decontamination and dismantlement work proceeds, radiological surveys will be conducted to maintain a current site characterization and to ensure that decommissioning activities are adjusted accordingly.

As part of the site characterization process, a neutron activation analysis calculation study of the reactor internals and the reactor vessels will be performed. Using the results of this analysis (along with benchmarking surveys), neutron irradiated components will be classified (projected for the future D&D time frame) in accordance with 10 CFR 61, "Licensing requirements for land Page 16 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report disposal of radioactive waste." The results of the analysis form the basis of the plans for removal, segmentation, packaging, and disposal.

2.2.6 Groundwater Protection and Radiological Decommissioning Records Program A Radiological Groundwater Protection Program (RGPP) currently exists at DNPS-2/3 in accordance with the Nuclear Energy Institute (NEI) Technical Report 07-07, "Industry Groundwater Protection Initiative - Final Guidance Document" (Reference 6). This program is directed by procedures and will continue during decommissioning.

Neither the monitoring results of the radiological groundwater protection program nor events noted in 10 CFR 50.75(g) reports indicate the presence of radionuclides in concentrations sufficient to preclude unrestricted release under 10 CFR 20.1402, "Radiological criteria for unrestricted use."

Exelon will also continue to maintain the existing radiological decommissioning records program required by 10 CFR 50.75(g). The program is directed by procedures.

2.2. 7 Changes to Management and Staffing Throughout the decommissioning process, plant management and staffing levels will be adjusted to reflect the ongoing transition of the site organization. Staffing levels and qualifications of personnel used to monitor and maintain the plant during the various periods after plant shutdown will be subject to appropriate Technical Specifications and Emergency Plan requirements. These staffing levels do not include contractor staffing which may be used to carry out future activities, plant modifications in preparation for SAFSTOR, and the D&D I license termination I site restoration work. Contractors may also be used to provide general services, staff augmentation, or replace permanent staff. The monitoring and maintenance staff will be comprised of radiation protection, radiological environmental monitoring program, plant engineering and craft workers as appropriate for the anticipated work activities.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 3

SCHEDULE OF PLANNED DECOMMISSIONING ACTIVITIES Exelon intends to pursue the decommissioning of DNPS-2/3 utilizing a SAFSTOR methodology and will make appropriate submittals with the NRC to obtain authorization prior to beginning radiological decommissioning. The SAFSTOR method involves removal of radioactively contaminated or activated material from the site following a period of dormancy before active decontamination and dismantlement begins. Work activities associated with the planning and preparation period began before the plant was permanently shutdown and continues until all fuel is removed from the reactor vessels and stored in the SFPs. The schedule of spent fuel management and major decommissioning activities is provided in Table 2.1. Additional detail is provided in the site-specific DCE. Dates in the site-specific DCE are based on a November 2021, shutdown date. The schedule accounts for spent fuel being stored in the ISFSI until the assumed date of transfer to the DOE.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 4

ESTIMATE OF EXPECTED DECOMMISSIONING AND SPENT FUEL MANAGEMENT COSTS 10 CFR 50.82(a)(4 )(i) requires the submission of a PSDAR prior to or within two years following permanent cessation of operations that contains a site-specific DCE, including the projected cost of managing irradiated (also called spent) fuel.

Exelon has prepared a DCE for DNPS-2/3, which provides the site-specific projected costs of radiological decommissioning, managing spent fuel, and site restoration; each category accounted for separately. The site-specific DCE will be submitted in a separate submittal.

Section 4.1 describes the projected expenditures in the DCE to produce Table 2.2.

The methodology used to develop the site-specific DCE follows the basic approach originally advanced by the Atomic Industrial Forum (AIF) in its program to develop a standardized model for DCEs. The results of this program were published as AIF/NESP-036, "Guidelines for Producing Commercial Nuclear Power Plant Decommissioning Cost Estimates," (Reference 7).

The AIF document presents a unit cost factor method for estimating direct activity costs, simplifying the estimating process. The unit cost factors used in the study reflect the latest available data, at the time of the study, concerning worker productivity during decommissioning.

Under NRC regulations (10 CFR 50.82(a)(8)), a licensee must provide reasonable assurance that funds will be available (or "financial assurance") for decommissioning (i.e., radiological decommissioning) costs. The regulations also describe the acceptable methods a licensee can use to demonstrate financial assurance. Most licensees do this by funding a nuclear decommissioning trust fund (DTF).

Exelon maintains two separate trusts for each unit for this purpose, a tax qualified fund (Qualified Trust) and a non-tax qualified fund (Non-Qualified Trust). The trustee for both funds is Northern Trust Bank. As of December 31, 2020, the DTF for DNPS-2 has a total balance of

$876,248,000 and the DTF for DNPS-3 has a total balance of $895,711,000 (Reference 8). The adequacy of these funds to cover all radiological decommissioning costs shown in Table 2.2 is demonstrated in the DNPS-2/3 site-specific DCE.

The 10 CFR 50.75(c) minimum formula amounts for DNPS-2/3 as of December 31, 2020 are both $653, 172,000 (Reference 8). The estimated cost of radiological decommissioning at DNPS-2 is $708,470,000 and at DNPS-3 is $748,515,000 based on the cost provided in the site-specific DCE escalated to December 2020 dollars (see Section 4.1 ). In accordance with Regulatory Guide 1.185 (Reference 1 ), the site-specific DCE exceeds the minimum formula amount.

10 CFR 50.82(a)(6)(iii) states that, "Licensees shall not perform any decommissioning activities," as defined in 10 CFR 50.2 that, "Result in there no longer being reasonable assurance that adequate funds will be available for decommissioning." Exelon does not intend to perform any decommissioning activities that would jeopardize the availability of adequate funds for the completion of decommissioning.

10 CFR 50.82(a)(8)(iv) states that, "For decommissioning activities that delay completion of decommissioning by including a period of storage or surveillance, the licensee shall provide a means of adjusting cost estimates and associated funding levels over the storage or surveillance period." Section 4.2 details how Exelon will meet this requirement.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 4.1 COST ESTIMATE ADJUSTMENTS Table 2.2 reflects the projected expenditures required for decommissioning DNPS-2/3 from the DCE escalated to December 31, 2020 dollars. The updated projected costs for radiological decommissioning, spent fuel management, and site restoration (non-radiological decommissioning) efforts are separately reflected in Table 2.2. Items to note relative to the costs are:

(1) The DCE is in June 2020 dollars. The costs reflected in Table 2.2 have been escalated to December 31, 2020, dollars.

The escalation was determined using a forecasted average annual escalation rate of 2.59% (based on the most recent data at the time of this submittal).

This rate was calculated using the Employment Cost Index Total Compensation Private Industry Workers United States from the North American Industry Classification System (NAICS).

(2) Projected radiological decommissioning planning costs incurred in 2021 prior to permanent shutdown are included in Table 2.2 under "Pre-Shutdown Planning."

Decommissioning Planning costs for prior years, associated with radiological decommissioning planning performed by a dedicated site organization, are not reflected in Table 2.2.

4.2 MEANS OF ADJUSTING COST ESTIMATES AND ASSOCIATED FUNDING LEVELS The site-specific DCE will be periodically updated in compliance with Exelon procedures and applicable regulatory requirements.

In accordance with 10 CFR 50.82(a)(8)(v), decommissioning funding assurance will be reviewed and reported to the NRC annually. The latest site-specific DCE adjusted for inflation, in accordance with applicable regulatory requirements, will be used to demonstrate funding assurance. In addition, actual radiological and spent fuel management expenses will be included in the annual report in accordance with the applicable regulatory requirements.

If the funding assurance demonstration shows the DTF is not sufficient, then an alternate funding mechanism allowed by 10 CFR 50.75(e) and the guidance provided in Regulatory Guide 1.159 (Reference 9) will be put in place.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report 5

ENVIRONMENTAL IMPACTS To support the PSDAR environmental impacts review, the environmental effects of decommissioning activities planned for DNPS-2/3, as currently understood, were evaluated to determine if potential environmental impacts are bounded by previously issued environmental impact statements (Reference 10). NRC regulation 10 CFR 50.82(a)(4 )(i) requires that the PS DAR include"... a discussion that provides the reasons for concluding that the environmental impacts associated with site-specific decommissioning activities will be bounded by appropriate previously issued environmental impact statements." To determine if the estimated potential environmental impacts associated with DNPS-2/3 decommissioning activities are bounded, the potential environmental impacts were compared to those in:

NUREG-0586, "Final Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities, Supplement 1, Regarding the Decommissioning of Nuclear Power Reactors" (Reference 4) (Referred to as the Decommissioning GEIS or GEIS)

NUREG-1496, "Generic Environmental Impact Statement in Support of Rulemaking on Radiological Criteria for License Termination of NRG-Licensed Nuclear Facilities" (Reference 111)

Atomic Energy Commission, "Final Environmental Statement Related to the Operation of Dresden Nuclear Power Station, Units 2 and 3" (Reference 12) (Referred to as the FES)

NUREG-1437, "Generic Environmental Impact Statement for License Renewal of Nuclear Plants, Supplement 17, Regarding Dresden Nuclear Power Station, Units 2 and 3" (Reference 13) (Referred to as the SEIS)

As required, site-specific impact assessments were conducted for threatened and endangered species and environmental justice. For the purpose of assessing decommissioning environmental impacts, the operational area at DNPS is comprised of the entirety of the DNPS site boundary. The decommissioning activities are anticipated to be confined to the operational area; therefore, additional site-specific assessments for aquatic ecology, terrestrial ecology, and cultural and historic resources were not required. The levels of significance assigned to site-specific environmental impacts are classified as small, moderate, or large, as defined by NRC in the Decommissioning GEIS (Reference 4 ).

DNPS's decommissioning plans are consistent with the methods assumed by NRC in the Decommissioning GEIS. No unique site-specific features or unique aspects of the planned decommissioning have been identified. Also, Exelon has concluded that the environmental impacts associated with planned DNPS-2/3 decommissioning activities are either bounded by the impacts addressed by previously issued environmental impacts statement or are expected, based on site-specific reviews, to be small. In the latter cases, after decommissioning plans mature and before decommissioning activities occur that could be potentially impactful to the environmental resource or would be otherwise inconsistent with those actions or activities described in the PSDAR, Exelon will notify the NRC in writing and seek appropriate environmental review in accordance with applicable NRC regulations.

5.1 ENVIRONMENTAL IMPACT OF DNPS-2/3 DECOMMISSIONING The following is a summary of the reasons for reaching the conclusion that the environmental impacts of decommissioning DNPS-2/3 are: (1) bounded by the Decommissioning GEIS, (2)

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report site-specific, small, and bounded by other previously issued environmental impact statements, or (3) expected to be site-specific and small, and Exelon will notify the NRC in writing and seek appropriate environmental review in accordance with applicable NRC regulations before decommissioning activities occur that could be potentially impactful to the environmental resource. Further, no unique site-specific features or unique aspects of the planned decommissioning have been identified.

5.1.1 Onsite I Offsite Land Use In Section 4.3.1 of the GEIS, the NRC generically determined land use impacts to be small for facilities having land-use changes only within the site boundary. For decommissioning that involves land use changes beyond the site boundary, the GEIS concluded that impacts could not be predicted generically and must be evaluated on a site-specific basis.

No offsite land is expected to be needed to support DNPS-2/3 decommissioning.

Onsite land is expected to be sufficient for decommissioning activities (e.g., laydown, staging, handling, temporary storage, processing, packaging, and shipping of waste and materials, personnel processing, and parking). Decommissioning and site restoration activities include backfill of excavations. The fill needed will be obtained from material (e.g., crushed concrete) resulting from onsite demolition. If additional fill is needed, it could be excavated from onsite or, if more appropriate or practical, fill could also be purchased from offsite borrow areas that are approved for that land use. The Illinois Environmental Protection Agency (IEPA) regulates the use of clean construction or demolition debris as fill for certain applications. Exelon will comply with state regulations regarding the use of fill materials and will obtain permits as needed.

Exelon has determined that onsite land to be used to support decommissioning at DNPS-2/3 has been previously disturbed and decommissioning activities at DNPS-2/3 would not result in changes in onsite land use patterns. After the site is released for unrestricted use, the land could continue as industrial use or be available for other nonindustrial uses. Exelon concludes that anticipated onsite land use impacts are bounded by the GEIS.

5.1.2 Water Use The GEIS observes that quantities of water required during decommissioning are trivial compared to those used when a plant is operating. The GEIS mentions construction dust abatement and decontamination (flushing systems or pressure-washing components) as typical decommissioning water uses. NRC asserted in Section 4.3.2 of the GEIS that potential impacts of decommissioning on water use at all plants are neither detectable nor destabilizing and made the generic conclusion that impacts in all cases are small.

DNPS-2/3 obtains surface water from the Kankakee River and discharges to the Illinois River downstream from the intake structure. Onsite groundwater wells supply water for potable water and demineralized water use.

Exelon expects to reduce DNPS-2/3 surface water and groundwater withdrawals substantially following plant shutdown. Upon shutdown of the circulating water system, the discharge of waste heat via the cooling towers will end which will eliminate most evaporative losses resulting from DNPS-2/3 operation. Water consumption will be further reduced when it is no longer necessary to provide secondary cooling for the SFPs.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report In accordance with the DNPS-2/3 National Pollutant Discharge Elimination System (NPDES) permit, when both units are taken out of service, the facility can operate in direct open cycle heat dissipation mode. Exelon will continue to withdraw water from the Kankakee River and discharge to the Illinois River but circulating water through the cooling pond and associated canals for heat removal (and the associated evaporation and seepage losses) will no longer be required. The cooling pond will be allowed to drain down to the top of the drop structure. This initial drawdown will occur quickly once the circulating water system pumps and the lift station pumps that transfer water from the hot canal to the cooling pond are permanently secured. The escaping water will flow through the cold canal to the discharge channel and be released to the Illinois River which is the current permitted cooling water discharge path. Shortly after this initial drawdown, siphons will be started at the lift station and the drop structure to draw the level of the pond down to the inside foot of the perimeter levee. DNPS-2/3 will continue to operate in open cycle mode until the irradiated fuel has been transferred to dry storage and cooling is no longer required for the SFPs. The transfer of irradiated fuel to dry storage is expected to be completed approximately 5 years after ceasing operation.

Based purely on staffing projections, the demand for potable water at the plant will be substantially lower during decommissioning years than during operational years, but it is conceivable that well water may also be required during decommissioning for dust abatement and decontamination. Nevertheless, Exelon expects groundwater use during DNPS-2/3 decommissioning to be much lower than water use during operational years, consistent with the statements made in the Decommissioning GEIS.

Because Exelon expects water use during DNPS-2/3 decommissioning to be much lower than water use during operational years, which is consistent with the statements made in the GEIS, and because there is nothing about DNPS's design, location, configuration, operating history, or decommissioning plans that would alter or contradict this generic conclusion, Exelon concludes that decommissioning water use impacts for DNPS-2/3 are bounded by the analysis in the GEIS.

5.1.3 Water Quality Decommissioning activities with potential for impacting surface water quality include fuel removal, stabilization, large component removal, decontamination and dismantlement, and structure dismantlement. Stormwater runoff and accidental releases (spills) are the most likely sources of pollutants entering surface waters during decommissioning. The GEIS asserts that regulatory programs applicable to permitted substance releases plus the application of Best Management Practices (BMPs) for controlling stormwater runoff and erosion will render any change in surface water quality from decommissioning activities nondetectable and non-destabilizing. With respect to groundwater, the GEIS noted that demolishing concrete structures and storing rubble on site could result in changes (higher alkalinity) in local water chemistry, but the non-radiological effects of such changes on water quality would be non-detectable offsite at all nuclear power plants. Furthermore, NRC noted in the GEIS that the Resource Conservation and Recovery Act would apply to concentrated subsurface placement of demolition debris, which would limit water quality effects from using rubble and soil as fill material.

During DNPS-2/3 decommissioning, compliance with permits and adherence to erosion and sediment controls, soil stabilization practices, structural practices, and pollution prevention Page 23 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report measures would ensure that water quality impacts from decommissioning are small and temporary. Any land-disturbing activities would be of relatively short duration, permitted and overseen by responsible regulatory agencies, and guided by !EPA-approved Erosion and Sediment Control BMPs. Exelon will continue to comply with applicable regulations which require reporting of hazardous material spills. All reasonable precautions will be taken to prevent or mitigate spills of hazardous materials. Exelon will comply with IEPA regulations regarding fill and obtain waste permits as needed. The IEPA encourages reuse and recycling of clean demolition debris and when carried out in accordance with IEPA requirements, would not adversely affect the groundwater quality in the area. Groundwater movement on the DNPS site is slow. If any localized alteration in the groundwater chemistry associated with the use of crushed concrete as clean fill were to occur, it is unlikely to impact the quality of groundwater in any aquifers that are a current or potential future source of water for offsite users.

Demolition of DNPS-2/3 structures and buildings and related earth-moving work has at least a limited potential to result in erosion and sedimentation that could affect water quality, but these kinds of construction activities routinely take place around operating nuclear power plants and are subject to the provisions of State-issued permits. Current plans call for blocking the ends of the intake and discharge canals during and after decommissioning. Bulkheads would be placed in both locations to prevent soil/debris/spills from entering the river(s) via the canals during structure and building demolition. The canals would then be backfilled. Coffer dams would be used to create a dry workspace for bulkhead construction and to contain soil displaced during bulkhead construction. A Clean Water Act (CWA) Section 404 permit would be obtained as needed for activities within the Illinois and Kankakee Rivers and Exelon would comply with any permit conditions imposed by the U.S. Army Corps of Engineers and cooperating state agencies.

In Section 4.3.3 in the GEIS, NRG concluded generically that for all facilities, decommissioning impacts to surface and groundwater quality would be small. Because there is nothing about the DNPS-2/3 design, location, configuration, operating history, or decommissioning plans that would alter or contradict this generic conclusion and Exelon would comply with regulatory and permit requirements to protect surface water and groundwater resources, Exelon concludes that decommissioning water quality impacts would be small and bounded by the Decommissioning GEIS.

5.1.4 Air Quality The GEIS identified decommissioning activities that may affect air quality, including worker transportation to and from the site, dismantling of systems and removal of equipment, movement and open storage of material onsite, demolition of buildings and structures, shipment of material and debris to offsite locations, and operation of concrete batch plants. NRG considered the potential for adverse impacts from these activities, the greatest of which would be fugitive dust, for the range of decommissioning plants and generically determined air quality impacts to be small.

IEPA permits and regulates air emissions under Title 35 of the Illinois Administrative Code (IAC)

Parts 201 and 212. Construction and demolition equipment including portable engines and portable concrete crushers would be subject to IEPA air emission unit regulations and permitting requirements. During DNPS-2/3 decommissioning, reasonable and appropriate control measures such as wetting of soil piles, covering loads and staging areas, and seeding of bare Page 24 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report areas would be implemented to control fugitive dust so that emissions do not extend offsite in compliance with IEPA regulations (35 IAC 212.301 ). Permits governing air emissions from the decommissioning activities and equipment would be obtained as required, and as needed, Exelon will maintain existing air permits for equipment that will continue to be used during DNPS-2/3 decommissioning. The exhaust from commuting and shipping vehicles could affect air quality somewhat, but it is unlikely that air quality would be degraded sufficiently to be noticeable beyond the immediate vicinity of Collins Road or Dresden Road.

In Section 4.3.4 in the GEIS, NRC concluded that the impacts of decommissioning on air quality would be neither detectable nor destabilizing and that current and commonly used mitigation measures should be sufficient. Because (1) the air quality impacts from decommissioning activities at DNPS-2/3 are expected to be temporary and localized, (2) reasonable and appropriate control measures would be employed, (3) the appropriate permits would be obtained, and (4) there is nothing about DNPS's location or decommissioning plans that would alter or contradict the generic conclusion in Section 4.3.4 of the GEIS, Exelon concludes that air quality impacts from DNPS-2/3 decommissioning activities are bounded by the analysis in the GEIS.

5.1.5 Aquatic Ecology Aquatic resources may be directly or indirectly impacted by decommissioning activities. Direct impacts to aquatic communities may result from shoreline or in-water construction or from dredging. Indirect impacts may result from construction-related erosion and stormwater runoff.

These impacts are typically undetectable (or barely discernible) and do not destabilize any important attributes of the resources. The GEIS determined that such decommissioning activities within the operational areas of nuclear power plants, including removal of shoreline or in-water structures, would have only minor impacts on aquatic communities, provided all appropriate BMPs are employed. Therefore, the GEIS concluded generically that aquatic impacts from decommissioning activities within a defined operational area would be small.

DNPS-2/3 withdraws water from the lower Kankakee River and sends its permitted discharges to the Illinois River. Two planned decommissioning activities at DNPS-2/3 have potential for impacting water quality in the Illinois and Kankakee Rivers, thus their aquatic communities:

filling the intake and discharge canals and dewatering the cooling pond. Assuming mitigation measures recommended (or required) by responsible state and federal resource agencies are employed, impacts to aquatic communities from intake and discharge canal filling (including retaining wall construction) are expected to be localized and temporary. Benthic macroinvertebrates and fish immediately downstream of the construction area would be exposed to higher levels of dissolved/suspended solids and increased turbidity during the construction phase. Fish normally move away from areas with high silt/sediment loads, so are affected only to the extent that they temporarily lose access to potential foraging and spawning habitats. Benthic communities are more likely to be affected, but typically recover once construction ceases and water quality conditions return to normal.

Exelon intends to dewater the cooling pond in stages as discussed in Section 5.1.2. The effect of silt/solids in the cooling pond effluent on Illinois River water quality would depend on levels of solids in the river and river discharge (flow). Emptying the cooling pond could, under very specific circumstances (e.g., rapid drawdown of the cooling pond when concentrations of solids are elevated and receiving water concentrations are low), affect water quality and fish habitat in Page 25 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report a short reach of the Illinois River. It is likely that impacts could be avoided or mitigated by timing releases, however.

Section 4.3.5 of the Decommissioning GEIS concluded that if decommissioning activities were restricted to the operational area and BMPs were adhered to, impacts to aquatic communities would be small. Exelon has determined that there would be minor impacts associated with filling the intake and discharge canals, including loss of benthic macroinvertebrates in two small areas where cofferdams are to be constructed. Additionally, dewatering the cooling pond could temporarily elevate levels of suspended solids and increase turbidity in the Illinois River downstream of the DNPS-2/3 discharge canal, but any impacts would be small and last only as long as water is discharged from the cooling pond. Given that (1) no decommissioning activities will take place outside of the operational area, (2) impacts from canal filling and cooling pond drawdown are expected to be minor and temporary, consistent with findings of the GEIS, and (3) there is nothing about DNPS's design, operation, location, or environs that would call into question the generic findings of the Decommissioning GEIS, Exelon concludes that impacts to aquatic communities from decommissioning would be small, and bounded by those described in the GEIS.

5.1.6 Terrestrial Ecology Section 4.3.6 of the Decommissioning GEIS maintains that "(f)or facilities where habitat disturbance is limited to operational areas, the impacts on terrestrial ecology (i.e., plant and animal communities) are not detectable or destabilizing," primarily because most vegetation and wildlife habitat in the operational area was removed during plant construction. NRC staff concluded that, "for such facilities... potential impacts to terrestrial ecology are small" and no further mitigation measures are warranted. Site-specific analysis is only required of licensees when decommissioning activities are likely to occur outside of the operational area, or if protected species are inhabiting portions of the operational area at the time of decommissioning (see Section 5.1.7).

Exelon has determined that land within the operational area is sufficient to provide space for laydown yards, equipment or materials storage, temporary offices, and other decommissioning support areas or structures. Current parking facilities have been adequate to support refueling and maintenance outages over the years and are assumed to be adequate to support decommissioning. Because there is ample open space to support DNPS-2/3 decommissioning operations, there would be no reason to clear any land outside of the site operational area.

Under current plans, all decommissioning activities will be confined to the operational area, which does contain some grasslands, patches of woods and depressional wetlands, but these habitats lie for the most part in close proximity to roads, transmission line rights-of-way, industrial facilities and DNPS facilities, thus are exposed to a fairly constant level of noise and human activity.

Terrestrial ecological communities in the vicinity of DNPS-2/3 are described in the site-specific environmental assessments listed in Section 5.0. The FES for DNPS Units 2 and 3 largely dismisses terrestrial ecological impacts because (1) the area that became DNPS had been converted to agricultural use in the 191.b. century and afterwards contained very little wildlife habitat other than pastures and stock ponds, and (2) virtually the entire site was subsequently disturbed during development and construction of Unit 1. The same logic applies to decommissioning. Areas that are likely to be disturbed during decommissioning were converted Page 26 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report from native prairie to agricultural use in the 19!.l:l century, disturbed again during the construction of Unit 1, and disturbed a third time during construction of Units 2 and 3.

In the Decommissioning GEIS, the NRG concluded that impacts from decommissioning on terrestrial resources are small provided these activities take place within the operational area, which is assumed to have minimal value as wildlife habitat. A site-specific analysis is only required when work related to decommissioning is conducted outside of the operational area.

Exelon intends to restrict all decommissioning activity at DNPS-2/3 to the operational area.

Because no sensitive resources (e.g., rare or unusual habitats, rare or protected species, important avian nesting/roosting areas) will be disturbed inside the operational area, Exelon has determined that decommissioning impacts at DNPS-2/3 would be small and should not require mitigation, beyond routine construction BMPs.

Having established that there is nothing unique about DNPS-2/3's design, operation, or location and having determined that impacts of DNPS-2/3 decommissioning on terrestrial resources would be similar to those described in previous NRG impact assessments, Exelon concludes that impacts of decommissioning on terrestrial resources would be small, and bounded by the analysis in the Decommissioning GEIS.

5.1. 7 Threatened and Endangered Species The GEIS lists stabilization, large component removal, decontamination, and dismantlement (removal of contaminated soil), and structure dismantlement as activities with potential to impact threatened and endangered species. The GEIS did not make a generic determination on the impact of decommissioning on threatened and endangered species but noted that impacts to these species are expected to be minor and non-detectable when activities are confined to the site operational area. Impacts are to be determined on a site-specific basis, paying particular attention to activities outside of the developed operational area. Noise and dust generation from construction activity and increased truck traffic, rather than direct impacts such as habitat destruction, are the primary concerns.

Exelon compiled the following list of State-and federally listed species that could occur in the vicinity of DNPS based on a review of pertinent ecological studies, long-term monitoring studies conducted by Commonwealth Edison and Exelon, NRG National Environmental Protection Act (NEPA) documents related to Dresden operations, and queries of state (EcoCAT) and federal (IPaC) databases.

Table 5-1:

Protected Species Potentially Occurring in DNPS Vicinity Through 2020 Scientific Name Common Name Mammals Myotis soda/is Indiana bat Myotis septentrionalis Northern long-eared bat Birds Asia flammeus I Short-eared owl Page 27 of 42 Federal Status E

T NL State Status E

T E

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Federal Scientific Name Common Name Status Botaurus lentiginosus American bittern NL Circus hudsonius Northern harrier NL Haliaeetus leucocephalus Bald eagle*

NL lxobrychus exilis Least bittern NL Nycticorax nycticorax Black-crowned night-heron NL Pandion ha/iaetus Osprey NL Ralf us e/egans King rail NL Reptiles Emydoidea blandingii Blanding's turtle NL Sistrurus catenatus E. massasauga (rattlesnake)

T Fish Ammocrypta c/ara W. sand darter NL Fundulus diaphanus W. banded killifish NL Hybopsis amnis Pallid shiner NL Moxostoma carinatum River redhorse NL Moxostoma valenciennesi Greater redhorse NL Notropis chalybaeus lroncolor shiner NL Notropis heterolepis Blacknose shiner NL Mussels Cyc/onaias tubercu/ata Purple wartyback NL Leptodea leptodon Scaleshell mussel E

Plethobasus cyphyus Sheepnose mussel E

Insects Aflexia rubranura Red-veined prairie leafhopper NL Bombus affinis Rusty-patched bumble bee E

Papaipema eryngii Eryngia stem-borer moth c

Somatoch/ora hineana Hine's emerald dragonfly E

Speyeria ida/ia Regal fritillary NL Plants Asclepias meadii Mead's milkweed T

Ca/opogon ok/ahomensis Oklahoma grass pink orchid NL Calopogon tuberosus Grass pink orchid NL Page 28 of 42 State Status E

E NL T

E T

E E

E E

T E

T E

T E

T E

E T

E T

E T

E E

E

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Scientific Name Common Name Corallorhiza maculata Spotted coral-root orchid Oa/ea fo/iosa Leaf prairie-clover Drosera intermedia Narrow-leaved sundew Hymenoxys herbacea Lakeside daisy aka Tetraneuris herbacea Luzula acuminata Hairy woodrush Malvastrum hispidum False mallow Minuartia patula Slender sandwort Platanthera /eucophea E. prairie fringed orchid NL= not listed; E = Endangered; T =Threatened: C =Candidate for listing

• has full legal protection under Bald and Golden Eagle Protection Act

5. 1. 7. 1 Protected Terrestrial Species Federal Status NL E

NL T

NL NL NL T

State Status E

E T

E E

E T

E Decommissioning activities with greatest potential for directly and indirectly affecting terrestrial plant and animal communities are those involving demolition of major reactor structures and filling of cooling water system canals. As discussed previously, land within the operational area is sufficient to provide space for laydown yards, equipment or materials storage, temporary offices, and other decommissioning support areas or structures. Because there is ample open space to support DNPS-2/3 decommissioning operations, there would be no reason to clear any land outside of the site operational area. Therefore, there would be no direct impacts to the habitat of any threatened or endangered species.

Demolition of DNPS-2/3 buildings and structures and filling of canals in the developed part of the site will disturb wildlife, but common species accustomed to noise and disturbance rather than rare or sensitive species. All of the demolition activities expected to generate extremely high noise levels will take place in the heavy-industrial part of the site, an area normally avoided by sensitive species and well removed from the grasslands, wetlands, and woods to the west.

None of the species in Table 5.1 have been observed in or around DNPS industrial facilities.

Filling the DNPS-2/3 cooling and intake/discharge canals will involve substantial land disturbance and Exelon would work with the Illinois Department of Natural Resources (IDNR) in planning their restoration. Plant communities of some landscaped areas around the canals will be affected, but no rare or unusual plant species are believed present. Wildlife in wooded areas adjacent to the intake canal and the portion of the "cold" canal that extends north to the Illinois River will be disturbed, as will wildlife in grasslands along canals south of the generating facilities. Birds and more-mobile mammals in these areas will disperse to nearby wildlife reserves and forest preserves, such as Goose Lake Prairie State Natural Area, McKinley Woods, and Des Plaines State Fish and Wildlife Area. There is an abundance of undisturbed, high-quality woodland and prairie habitat within a mile of the DNPS generating facilities and cooling canals.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report

5. 1. 7. 2 Protected Aquatic Species Based on a review of the scientific literature, surveys conducted by Commonwealth Edison and Exelon, and queries of state and federal databases, seven state-listed fish, one state-listed mussel (purple wartyback), and two federally listed mussels (scaleshell and sheepnose) could occur in the project vicinity (see Table 5.1 ). Although cofferdams and bulkheads will be employed to reduce the likelihood of disturbed soil reaching the Illinois and Kankakee Rivers, it is conceivable that site prep work for the bulkheads could result in some downstream siltation.

Exelon will consult with IDNR to determine if surveys of the eight state-listed aquatic species are warranted and if mitigation measures would be appropriate.

The United States Fish and Wildlife Service (USFWS) IPaC response indicated that the federally listed scaleshell mussel could occur in the project vicinity. This species was assumed to have been extirpated from the Illinois River until 2013, when a small number of specimens were discovered in the Marseilles Pool. Any scaleshell mussels that might survive in the Illinois River are presumed to be downstream of the Dresden Lock and Dam and therefore unlikely to be affected by decommissioning activities at DNPS. However, prior to placement of cofferdams, Exelon will conduct an informal Section 7 [Endangered Species Act, lnteragency Cooperation]

consultation to ensure that any concerns the USFWS may have with regard to this species are addressed.

Under Section 7, federal agencies must consult with the USFWS when any action the agency carried out, funds, or authorizes (through a permit), "may affect" a listed species. The first step is normally an informal consultation, essentially discussions between the agency and the Service about what species are present and possible project impacts on the species. If the species is unlikely to be affected, there is no requirement to consult formally.

The IPaC review also indicated that sheepnose mussels could occur in the project vicinity.

Although no sheepnose mussels survive in the Illinois River, a "stable" population persists in the lower Kankakee River, in a river reach that extends 30 miles downstream from the Kankakee River-Iroquois River confluence (77 Federal Register 14923-14926). The lower end of this section of the Kankakee River is apparently the dam at Wilmington, Illinois, which is approximately 5.5 miles from the DNPS property and 10 miles from the DNPS-2/3 intake canal.

Although the likelihood of impacts to this population from DNPS-2/3 decommissioning appear remote, Exelon will conduct an informal Section 7 consultation with the USFWS regarding the sheepnose mussel as well.

5. 1. 7. 3 Conclusion NRC has determined that potential impacts of decommissioning on threatened and endangered species must be evaluated on a site-specific basis. All decommissioning activities at DNPS-2/3 will take place within the site operational area; therefore, impacts to terrestrial ecological resources are expected to be small. Exelon has determined that none of the planned decommissioning activities at DNPS-2/3 would disturb the natural habitat of any state or federally listed terrestrial species. Any indirect (disturbance-related) impacts from construction noise and human activity would be localized, of short duration, and ecologically insignificant.

Birds and mammals that are intolerant of noise and human activity are expected to simply avoid (or move away from) noisy construction sites. This includes the protected avian species in Table 5.1, several of which are known to occur in neighboring Goose Lake Prairie State Natural Area.

Page 30 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Land disturbance of greater than one acre would require an NPDES permit which would require Exelon to provide proof of consultation with IDNR regarding the presence of federal or state threatened or endangered species and if, applicable, measures to avoid or mitigate impacts to protected species and their habitat. State and federal resource agency staff will be consulted at the appropriate time to rule out the presence of previously undiscovered/unreported threatened or endangered species, and, if present, to ascertain if any mitigation measures are warranted.

Agency permitting requirements and the mitigation measures discussed in previous sections should minimize impacts to protected aquatic species, assuming they are present. State and federal resource agencies will be consulted before major decommissioning activities commence to ensure that no listed aquatic species has been discovered in the intervening years and that no species previously documented in either the Kankakee or Illinois River has, in the intervening years, been afforded state or federal protection.

Based on the site-specific findings summarized in this section, Exelon concludes that DNPS-2/3 decommissioning activities are unlikely to adversely affect any threatened or endangered species and will have no effect on any designated critical habitat. However, in the future, when DNPS-2/3 decommissioning activities, such as demolition or disturbance of land areas that could affect a protected species have been finally determined and scheduled, Exelon will update the site-specific assessment of environmental impacts to protected species in the PSDAR. To comply with its continuing obligation under 10 CFR 50.82(a)(6) to assure that no decommissioning activity that would result in significant environmental impacts would be performed without NRC review, the results of the assessment would be provided to the NRC in accordance with applicable NRC regulations.

5.1.8 Radiological The GEIS considered radiological doses to workers and members of the public when evaluating the potential consequences of decommissioning activities and concludes that radiological impacts of decommissioning activities are small.

5. 1. 8. 1 Occupational Dose One conclusion of the GEIS is that, based on decommissioning experience, occupational dose during decommissioning is comparable to that observed during routine operations at the same or similar facilities. Therefore, Exelon evaluated DNPS-2/3 operational dose data and compared it to that of other BWRs and established that DNPS-2/3 operating collective dose is typical of U.S. BWRs. Furthermore, Exelon calculated occupational collective dose expected during the decommissioning period using methodology from NUREG/CR-6174, "Revised Analysis of Decommissioning for the Reference Boiling Water Reactor Power Station" (Reference 144). The calculated decommissioning collective dose was lower than that reported in NUREG/CR-6174 for the reference BWR. Thus, DNPS-2/3 decommissioning occupational dose is expected to be within or below the range of doses presented in the GEIS. There are no unique characteristics at DNPS-2/3 that would invalidate this conclusion.

Exelon selected a deferred decommissioning strategy, ensuring that most exposure scenarios will result in lower occupational doses than those during operations due to the fact that the plant has been defueled and a short period of radioactive decay has reduced the radiological inventory. The DNPS As Low as Reasonably Achievable (or ALARA) program and regulatory limits on dose will remain in effect during decommissioning.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report

5. 1. 8. 2 Public Dose Section 4.3.8 in the GEIS states that radionuclide emissions in gaseous and liquid effluents are reduced in facilities undergoing decommissioning. Given that DNPS-2/3 public doses during operations were well within the NRC-established public dose limits, it is reasonable to expect that public doses during decommissioning would also be well within such limits. Annual reports of environmental monitoring at DNPS for the years from 2015 through 2019 concluded that operation of DNPS had no adverse radiological impact on the environment. Controls on potential radiological releases will continue to be applied during decommissioning.

5. 1. 8. 3 Conclusion Exelon concludes that radiological impacts of DNPS-2/3 decommissioning are small for the following reasons:

The GEIS generic evaluation of radiological impacts applies to a typical BWR. Both occupational dose and public dose from normal DNPS-2/3 operations are like those of other BWR plants, indicating that DNPS-2/3 doses are typical.

The DNPS-2/3 collective worker dose estimate for the decommissioning periods is lower than that predicted by NUREG/CR-6174.

Exelon's selection of a Shortened SAFSTOR decommissioning option allows for radionuclides to decay over time, resulting in less dose at the time of dismantlement.

Current decommissioning plans fall within decontamination, dismantlement, and waste processing activities considered by NRC, and site-specific conditions do not represent unique conditions that would lead to a conclusion different than that reached in the Decommissioning GEIS.

Therefore, Exelon further concludes that the radiological impacts of DNPS-2/3 decommissioning are bounded by the analysis in the GEIS.

5.1.9 Radiological Accidents Section 4.3.9 in the GEIS examined a range of radiological accidents hypothetically possible during the decommissioning period. These included external events, non-nuclear fuel-related accidents, and nuclear fuel-related accidents. The GEIS concludes that impacts of radiological accidents of all types applicable to decommissioning activities are small.

Given their potential to result in offsite doses, the GEIS considered spent fuel accidents of most concern for decommissioning. Once in dry cask storage, however, spent fuel management is no longer within the scope of decommissioning environmental review because NRC evaluated the environmental impacts of continued spent fuel storage for all nuclear power plants in NUREG-2157, "Generic Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel" (Reference 15). Consequently, the only accidents of importance to offsite doses during decommissioning are those involving spent fuel in the SFPs. SFP accidents would no longer be applicable after the spent fuel is moved to dry cask storage. The most significant of the spent fuel accidents, in terms of consequences and probability, involves SFP drainage leading to a zirconium fire. However, NRC, in both NUREG-2157 and the GEIS, determined that the risk of a zirconium fire is very low (but, should it occur, the consequences could be high).

Page 32 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Spent fuel at DNPS-2/3 will, at a minimum, remain in the SFPs for as long as is required for cooling before being moved to dry storage. A zirconium fire accident is potentially possible (but very improbable) during a portion of the time that spent fuel is stored in the SFPs. Permanently Defueled Technical Specifications have been proposed for DNPS which mitigate this possibility.

The Updated Final Safety Analysis Report (UFSAR) describes the abnormal operational transients and design basis accident scenarios that are applicable during plant operations.

Exelon has concluded that most of the accident scenarios postulated in the UFSAR will no longer apply after DNPS-2/3 is in the permanently defueled condition (Reference 16).

The UFSAR accidents that will remain applicable to DNPS-2/3 in the permanently shutdown and defueled condition are the fuel handling accident in the SFPs and the liquid radioactive waste release due to tank failure. The UFSAR concludes that the doses associated with these accidents would be within the limits specified in 10 CFR Part 100. Exelon will respond to events at DNPS-2/3 in the reduced spectrum of credible accidents in the permanently defueled condition and retain the ability to promptly implement the SFP mitigation actions.

Also, Exelon knows of no unique features or conditions at DNPS-2/3 that would lead to a conclusion concerning radiological accidents different than that reached in the GEIS. Therefore, Exelon Generation concludes that accident impacts of decommissioning activities at DNPS-2/3 are bounded by those in the Decommissioning GEIS, resulting in small impacts.

5.1.10 Occupational Issues Section 4.3.10 of the GEIS concluded that impacts due to occupational issues would be small for all plants based on strict adherence to NRC and Occupational Safety and Health Administration (OSHA) safety standards, practices, and procedures.

DNPS-2/3 decommissioning will be conducted under a comprehensive non-radiological safety and health program meeting OSHA, NRC, and Exelon procedural requirements. Exelon facilities have lower rates of injuries and illness than the national average for electrical utilities, and historically, the nuclear power industry has lower rates of injuries and illnesses than other industries.

The DNPS-2/3 site-specific decommissioning activities and methods for carrying out the actives are within the range of those evaluated in the GEIS. Accordingly, Exelon concludes that anticipated impacts resulting from non-radiological occupational issues during DNPS-2/3 decommissioning are small and thus bounded by the analysis in the GEIS.

5.1.11 Cost A site-specific decommissioning cost estimate is summarized in Section 4.0.

5.1.12 Socioeconomics The GEIS evaluated changes in workforce and population, changes in local tax revenues, and changes in public services for decommissioning. The NRC considered the decreases in workforce and tax payments related to the cessation of operations (plant closure) outside the scope of decommissioning. The GEIS concluded that socioeconomic impacts caused by decommissioning are neither detectable nor destabilizing and that mitigation measures are not warranted.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report As DNPS-2/3 ceases operation and transitions through the phases of decommissioning, an overall decrease in plant workforce and tax payments will occur, primarily impacting Grundy and Will Counties, where the majority (67 percent) of the permanent plant workforce resides and whose taxing districts receive DNPS tax payments. The initial workforce reduction and the reduction in DNPS's fair market value and a corresponding reduction in tax liability would be attributable to plant closure. The station workforce reduction attributable to decommissioning with the greatest impact on the population would result in less than 1 percent decrease in Grundy County's population and have a lesser effect on Will County's population. Changes in tax liabilities attributable to decommissioning would be minimal.

Based on the findings summarized above, Exelon concludes that impacts to socioeconomic resources attributable to DNPS-2/3 decommissioning would be small and thus bounded by the analysis in the GEIS.

5.1.13 Environmental Justice Section 4.3.13 of the GEIS determined environmental justice to be an environmental impact area for which no generic conclusion could be determined due to its site-specific nature.

Therefore, the GEIS indicates that site-specific assessments for each decommissioning nuclear power plant must be prepared.

Exelon prepared a site-specific assessment of environmental justice as it relates to the effects of DNPS-2/3 decommissioning. Exelon examined the geographic distribution of minority and low-income populations within a 50-mile radius of the DNPS site using the 2014-2018 American Community Survey 5-year estimates. Census block groups containing minority populations were identified and most are concentrated in and around the city and suburbs of Chicago. The nearest minority population blocks are located in the cities of Channahon, Joliet, and Shorewood, about 10 miles northeast of DNPS. Most census block groups containing low-income populations are concentrated in and around the city and suburbs of Chicago. The nearest low-income populations are located in the cities of Channahon, Joliet, and Shorewood, about 10 miles northeast of DNPS.

Exelon determined that impacts as a result of decommissioning activities to all resource areas would be small, indicating that the effects are not detectable or are so minor that they will neither destabilize nor noticeably alter any important attribute of the resource. Because no member of the public will be substantially affected, there can be no disproportionately high and adverse impact or effects on minority and low-income populations resulting from the decommissioning of DNPS. Based on these site-specific findings, Exelon concludes that the impacts of decommissioning DNPS-2/3 on minority and low-income populations are small.

Even so, after decommissioning plans mature and before decommissioning activities occur that could be potentially impactful to minority and low-income populations or would be otherwise inconsistent with those actions or activities described in the PSDAR, Exelon will notify the NRC in writing and seek appropriate environmental review in accordance with applicable NRC regulations.

5.1.14 Cultural, Historical, and Archaeological Resources Section 4.3.14 of the GEIS determined that potential effects of decommissioning on cultural, historical, and archaeological resources would be small for all plants when the decommissioning activities are confined to the operational area. However, impacts outside the operational area Page 34 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report "must be determined through site-specific analysis." Exelon anticipates that decommissioning activities will take place within the DNPS operational area.

Exelon conducted a review of available information including data on locations of inventoried resources from the Illinois State Historic Preservation Office (IL-SHPO), the Illinois Archaeological Survey (IAS), and the National Park Service (NPS) about cultural, historical, and archaeological resources for the DNPS and an approximately 6-mile radius.

Currently, five archaeological sites have been recorded within the DNPS operational area, of which two (Sites 11 GR2 and 11 GR457) represent prehistoric Native American localities and three (Sites 11 GR461, 11 GR462, 11 GR463) are historic period agriculture-related localities dating to the twentieth and possibly, in one instance, the nineteenth century. Site 11 GR2, situated east of the power block, was first recorded as an archaeological site in the 1920s, but has not been investigated professionally, so it is unevaluated with respect to eligibility for listing on the National Register of Historic Places (NRHP). The remaining four sites were identified during an archaeological survey in 2018 within the northwestern quadrant of the operational area for a proposed natural gas pipeline. None of these four sites was recommended as NRHP eligible. The Illinois Inventory of Archaeological Sites records 407 sites within 6 miles of DNPS, including three nearby sites (within 600 feet of the operational area), two of which are small prehistoric localities to the east of the operational area (Sites 11 GR391 and 11 GR392) and one of which, located west of the operational area, is the remnant of a circa 1900 windmill for pumping water (Site 11 GR464 ). None of these nearby sites is NRHP eligible.

Five properties and historic districts listed on the NRHP are situated within the 6-mile radius of DNPS. These include one prehistoric period habitation and mortuary archaeological site and two nineteenth-century industrial archaeological sites, along with the Illinois and Michigan Canal (1848-1936) and Dresden Island Lock and Dam Historic District (Lock & Dam No. 4), built 1929 to 1933. These latter two historic properties are situated within 1 mile of the DNPS. As of January 2021, there are no aboveground properties within 6 miles of DNPS that the IL-SHPO considers to be NRHP-eligible but have not actually been listed.

Current planning anticipates that decommissioning activities for DNPS Units 2 and 3 will be limited to the operational area. Exelon intends to avoid ground disturbances during decommissioning in areas where extensive construction activity has not previously occurred.

Exelon is aware that Site 11 GR2, which as noted has neither been professionally investigated nor evaluated for NRHP eligibility, is situated between the east side of the power block and the Kankakee River, and Exelon intends to avoid significant ground disturbance in that area. In this regard it is also important to note that ground disturbance of greater than one acre would be subject to the IEPA general construction stormwater NPDES permit, Permit No. ILR10. The permit conditions require prior approvals from the IL-SHPO regarding potential impacts to cultural sites. Decommissioning activities within previously disturbed portions of the operational area will not impact cultural resources. Exelon will, in accordance with its standard procedures, take steps to assess archaeological sensitivity prior to commencing ground-disturbing activities and, as appropriate, consult with IL-SHPO for areas beyond that where extensive construction activity has not previously occurred.

Clean backfill for demolished building and structure foundations will be sourced from onsite demolition activities and borrow areas within the operational area. If required, additional clean fill will be obtained from offsite sources meeting local and state permitting and regulatory Page 35 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report requirements. The topsoil covering placed during site restoration will also be sourced from within the operational area or offsite as needed. It is anticipated that offsite sources will represent previously disturbed land or other areas already cleared of cultural resources.

In Section 4.3.14.2 of the GEIS, NRC noted the potential for the nuclear facility itself to be potentially eligible for inclusion in the NRHP, especially if it is older than 50 years and represents a significant historic or engineering achievement. All three reactor units at the DNPS have now reached the 50-year threshold for routine, non-exceptional assessment of possible eligibility to the NRHP (36 CFR Part 60 and 800). To date, none has been evaluated for potential NRHP eligibility, and Exelon has no plans to initiate evaluation or nomination. Current plans envision that dismantlement activities at the station will begin in 2029. Exelon plans to create an archive of photographs, plans, and other supporting materials to document the history of, specifically, Unit 1, and donate these materials to an appropriate repository. Exelon will consult with IL-SHPO regarding this documentation plan prior to dismantling DNPS.

In light of these plans and considerations, Exelon concludes that impacts to cultural and historical resources from DNPS-2/3 decommissioning are bounded by the Decommissioning GEIS.

5.1.15 Aesthetic Issues In Section 4.3.15 of the GEIS, the NRC singles out structure dismantlement and entombment as the only activities that may have impacts on aesthetic resources. The aesthetic impacts of decommissioning fall into two categories: (a) impacts, such as noise, associated with decommissioning activities that are temporary and cease when decommissioning is complete and (b) the changed appearance of the site when decommissioning is complete. NRC drew the generic conclusion that for all plants, the potential impacts from decommissioning on aesthetics are small and that the removal of structures is generally considered beneficial to the aesthetics of the site.

During DNPS-2/3 decommissioning, the impact of noise and dust would be temporary and controlled to minimize impacts. The appearance of DNPS-2/3 will be altered as the buildings and structures are dismantled and canals are backfilled. There are clear views of the taller plant structures from the adjacent rivers and surrounding land. The view of the cooling water system's canals and cooling pond area is more localized. The canals will be backfilled, and aesthetic impacts would be limited to the filling activities and exhaust and dust. During decommissioning, the cooling pond's water level will be lowered and the eastern third will be dry. The cooling pond has embankments that obscure the view of the water along much of its perimeter with the water visible to only a few residences along Lorenzo Road. Once the water level is lowered, the cooling pond property will continue to dry with intermittent wetter periods and naturally revegetate, creating a more natural setting.

The visual intrusion during dismantlement would be temporary and would serve to reduce the aesthetic impact of the site. The changed appearance of the site when decommissioning is complete would generally be considered beneficial to the aesthetics of the site. Therefore, Exelon concludes that the impacts of DNPS-2/3 decommissioning on aesthetics are small and generally considered beneficial. Thus, such impacts are bounded by the analysis in the GEIS.

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5.1.16 Noise Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Section 4.3.16 of the GEIS generically examined noise during decommissioning, concluding that noise impacts would be small.

Decommissioning activities will be primarily limited to previously disturbed land surrounding the power block and along the cooling canals. The noise levels associated with the decommissioning activities are not expected to be any more severe than during the initial construction of the station or refueling outages and are not expected to present an audible intrusion on the surrounding community and environment. In the immediate area surrounding DNPS are residences, industrial facilities, transportation infrastructure, rivers, and conservation areas. The NRC considered noise impacts from decommissioning of DNPS-2/3 in the license renewal SEIS stating "Noise would be generated during decommissioning operations that may be detectable off-site; however, the impact is unlikely to be of significance, and noise would cease altogether following decommissioning" (Reference 133). Activities at DNPS would have to follow applicable federal, state, or local guidelines and regulations on noise. Illinois has a noise regulation with allowable octave band sound levels according to emitting and receiving land-use classification and time of day (Illinois Administrative Code (IAC), Title 35:

Environmental Protection, Subtitle H: Noise). Grundy County has ordinances with nuisance clauses (Sections 4-8 1 and 8-4-4-1) against construction noise for nighttime hours but has established no quantitative noise limits.

NRC also considered the higher noise levels of demolition methods including use of pneumatic drills or explosives and concluded that environmental effects may be minimized by proper scheduling due to the short duration and isolated use of such methods. The consideration of these higher noise activities in Section 0.1.4 of the GEIS did not alter NRC's conclusion that it is unlikely that the noise associated with most decommissioning activities will be of sufficient strength to be environmentally detectable or to destabilize the environment.

Therefore, because DNPS-2/3 decommissioning activities are of the type previously considered by NRC and DNPS-2/3 has no site-specific conditions that would alter the NRC's prior findings, Exelon concludes that the noise impacts from decommissioning activities would be small and thus bounded by the analysis in the GEIS.

5.1.17 Transportation In Section 4.3.17 of the GEIS, NRC states that its "... regulations are adequate to protect the public against unreasonable risk from the transportation of radioactive materials." Therefore, the effects of transportation of radioactive waste on public health and safety are considered to be neither detectable nor destabilizing. Exelon will comply with NRC and Department of Transportation regulations for shipments of radioactive waste from DNPS-2/3 decommissioning.

The GEIS analyzes radiological shipments of waste from decommissioning and calculates incident-free doses and latent cancer fatalities to crew, the public along the route, and onlookers. The GEIS also calculates the collective dose for radiological accidents during transportation. The calculated impacts are closely related to the distance shipped, volumes shipped, and activity levels. The estimated volumes of radioactive waste associated with DNPS-2/3 decommissioning are summarized in the Table 5.2 using waste types from the GEIS (Reference 4) and waste volumes from the DNPS-2/3 decommissioning cost estimate. The volumes presented in Table 5.2 are on a single unit basis using the higher of the estimates for Page 37 of 42

Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report DNPS Unit 2 or Unit 3. This allows for comparison with the NRC's analysis in the GEIS for decommissioning of single reactor sites based on past decommissioning experience.

Table 5-2:

Estimated Radioactive Waste Associated with DNPS-2/3 Decommissioning Waste Type High-activity waste Class Band C Class A Low-activity waste (Class A)

Very low-activity waste (Class A)

Volume (ft3)

(per Unit) 5,383 51,734 7,160 386,094 Exelon considered a bounding scenario in which the Class A wastes are shipped to the EnergySo/utions disposal site in Utah and Class B and C wastes are shipped to the Waste Control Specialists Facility in Texas. All wastes were assumed to be shipped via truck.

Transportation impacts would be reduced to the extent waste is shipped to the disposal site via rail.

For the following reasons, if radiological impacts alone are considered, the conclusions in the GEIS would bound the impacts of transportation of radioactive waste from DNPS-2/3 decommissioning. For DNPS, the volume estimated per unit for high-activity waste is higher than the waste volume that NRC assumed in the Decommissioning GEIS. While the waste volume for disposal from DNPS-2/3 is higher, other considerations greatly reduce worker and population exposure. The DNPS rail spur could be refurbished and used for radioactive waste shipments. The NRC indicates in the GEIS that use of rail reduces radiological impacts by more than a factor of 10 over truck shipments. In addition, the distances traveled to disposal sites available to DNPS are significantly lower (less than half) than were analyzed in the GEIS. In the GEIS evaluation, the low-activity waste shipments were assumed to exhibit lower external dose rates (i.e., one-tenth of regulatory limits) and for very low-activity waste are sufficiently small that the activity may be neglected in evaluating the radiological impacts of transportation. Very low-activity waste is expected to comprise 86 percent of the overall DNPS-2/3 waste volume and would have negligible radiological impacts.

Section 4.3.17 of the GEIS recognizes non-radiological impacts of transportation to include increased traffic, wear and tear on area roadways, and increased traffic accidents from both radiological and non-radiological transport, including that for hazardous waste. NRC concluded that transporting materials to and from a decommissioning site would not significantly impact the overall traffic volume or compromise the safety of the public. DNPS's waste shipments are not expected to be large enough in number to have a detectable or destabilizing effect on traffic flow or road wear. The number of workers during the decommissioning phases is expected to be considerably less than the current onsite workforce and well below the temporary workers during refueling outages. Consequently, challenges to the existing transportation infrastructure are not expected.

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report The GEIS concludes that both non-radiological and radiological impacts of decommissioning transportation are small. No unique features or site-specific conditions are present at DNPS-2/3 that would alter these NRC prior findings. Therefore, Exelon concludes that transportation impacts of DNPS-2/3 decommissioning would be small and thus bounded by the analysis in the GEIS.

5.1.18 Irreversible and Irretrievable Commitment of Resources Section 4.3.18 of the GEIS generically concluded that the impacts of decommissioning on irreversible and irretrievable commitments of resources are small. Given that DNPS-2/3 would be decommissioned to radiological standards for unrestricted release, the land will be available for other uses. Furthermore, the materials and fuel consumed during DNPS-2/3 decommissioning would be minor. The decommissioning of DNPS-2/3 would generate radioactive waste and non-radiological waste requiring land disposal. Land devoted to radioactive waste disposal sites or industrial landfills was not within the scope of the GEIS because such commitments are addressed in the licensing documents for the disposal sites.

Therefore, Exelon concludes that the impacts of DNPS-2/3 decommissioning on irreversible and irretrievable commitments of resources would be small and thus bounded by the analysis in the GEIS.

5.2 ENVIRONMENTAL IMPACTS OF LICENSE TERMINATION - NUREG-1496 According to the schedule provided in Section 3 of this report, a L TP for DNPS-2/3 will be developed and submitted to NRC approximately two years prior to the anticipated license termination date. The L TP will include a supplement to the DNPS-2/3 PSDAR Environmental Report describing any new information or significant environmental change associated with the proposed termination activities. Although the L TP, including a supplement to the Environmental Report, need not be prepared and submitted until a minimum of two years prior to the anticipated license termination date, as required by 10 CFR 50.82(a)(9), the absence of any unique site-specific factors, significant groundwater contamination, unusual demographics, or impediments to achieving unrestricted release indicate that impacts resulting from DNPS-2/3 license termination will be similar to those evaluated in NUREG-1496 (Reference 11 ).

5.3 DISCUSSION OF DECOMMISSIONING IN THE SEIS As part of the DNPS license renewal, decommissioning was addressed in Chapter 7 of the SEIS (Reference 13). The NRC reviewed the Category 1 issues applicable to decommissioning and indicated that there were no Category 2 issues related to decommissioning. NRC did not identify any new and significant information during their review. Therefore, NRC concluded that there would be no impacts beyond those discussed in the GEIS for License Renewal of Nuclear Plants, NUREG-1437 and the impacts would be small (Reference 13). There are no contemplated decommissioning activities that would alter that conclusion.

5.4 ADDITIONAL CONSIDERATIONS The following considerations are relevant to concluding that DNPS-2/3 decommissioning activities prior to license termination will not result in significant environmental impacts not previously reviewed:

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report Continued compliance with radiological release and dose regulatory limits and adherence to plant procedures for monitoring and controlling releases and the and the Offsite Dose Calculation Manual, Continued site access control to minimize or eliminate radiation release pathways to the

public, Transport of radioactive waste in accordance with plant procedures, applicable federal regulations, and the requirements of the receiving facility, Continuation of the Radiological Environmental Monitoring Program until no longer necessary and continuation of radiological groundwater protection program as needed, Continued adherence to ALARA principles during decommissioning and compliance with occupational dose limits, Continued compliance with applicable regulations and permit conditions, and Continued storage of spent fuel in accordance with license and plant procedures.

5.5 CONCLUSION

S Exelon evaluated the site-specific impacts anticipated from decommissioning of DNPS-2/3 for each environmental resource area in the same manner and context as used by NRC in its GEIS (Reference 4). This evaluation indicates that DNPS-2/3 decommissioning activities fall within the range of decommissioning activities considered by NRC in the GEIS. There are no unique aspects of the plant or the expected decommissioning techniques that would invalidate the applicability to DNPS-2/3 of the GEIS conclusions. The evaluation indicates that the impacts of DNPS-2/3 decommissioning are bounded by the GEIS' assessment for those environmental issues for which NRC made generic determinations. For the areas where a site-specific assessment was required, the anticipated impacts from DNPS-2/3 decommissioning were determined to be small. In addition, after decommissioning plans mature and before decommissioning activities occur that could be potentially impactful to the environmental resource or would be otherwise inconsistent with those actions or activities described in the PSDAR, Exelon will notify the NRC in writing and seek appropriate environmental review in accordance with applicable NRC regulations.

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6 REFERENCES Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report

1. Regulatory Guide 1.185, "Standard Format and Content for Post-Shutdown Decommissioning Activities Report," Revision 1, dated June 2013 (ADAMS Accession No. ML13140A038)

2. Letter from J. Bradley Fewell (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Certification of Permanent Cessation of Power Operations for Dresden Nuclear Power Station, Units 2 and 3," dated September 2, 2020 (ADAMS Accession No. ML20246G627)

3. a. Letter from Richard P. Tuetken (Commonwealth Edison Company) to U. S. Nuclear Regulatory Commission - " Dresden Nuclear Power Station Unit 1, Post-shutdown Decommissioning Activities Report," dated June 1, 1998 (ADAMS Legacy Accession No. 9806080055)

b. Letter from K. A. Ainger (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Changes to Post-Shutdown Decommissioning Activities Report," dated August 23, 2001

c.

Letter from Keith R. Jury (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Update to Dresden Nuclear Power Station Unit 1 Post-Shutdown Decommissioning Activities Report," dated January 5, 2007 (ADAMS Accession No. ML070050166) d Letter from Michael P. Gallagher (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission, "Update to Dresden Nuclear Power Station Unit 1 Post-Shutdown Decommissioning Activities Report," dated March 16, 2018 (ADAMS No.

ML18078A140)

4. U.S. Nuclear Regulatory Commission, NUREG-0586, Supplement 1, "Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities," November 2002 (ADAMS Accession Nos. ML023470304 (Vol. 1) and ML023470323 (Vol. 2))

5. NUREG-1575, "Multi-Agency Radiation and Site Investigation Manual (MARSSIM),"

Revision 1, August 2000

6. Nuclear Energy Institute (NEI) Technical Report 07-07, "Industry Groundwater Protection Initiative - Final Guidance Document," August 2007

7. Atomic Industrial Forum, AIF/NESP-036, "A Guideline for Producing Commercial Nuclear Power Plant Decommissioning Cost Estimates," May 1986

8. Letter from Patrick R. Simpson, (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "Report on Status of Decommissioning Funding for Reactors and Independent Spent Fuel Storage Installations," dated February 24, 2021 (ADAMS Accession No. ML21055A776)

9. U.S. Nuclear Regulatory Commission, Regulatory Guide 1.159, "Assuring the Availability of Funds for Decommissioning Nuclear Reactors," Revision 2, dated October 2011 (ADAMS Accession No. ML112160012)

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Dresden Nuclear Power Station, Units 2 & 3 Post-Shutdown Decommissioning Activities Report

10. "Environmental Report, Post-Shutdown Decommissioning Activities Report, Dresden Nuclear Power Station Units 2 and 3," dated April 1, 2021

11. U.S. Nuclear Regulatory Commission, NUREG-1496, "Generic Environmental Impact Statement in Support of Rulemaking on Radiological Criteria for License Termination of NRG-Licensed Nuclear Facilities," July 1997 (ADAMS Accession No. ML042310492)

12. U.S. Atomic Energy Commission, "Final Environmental Statement Related to the Operation of Dresden Nuclear Power Station, Units 2 and 3," November 1973 (ADAMS Accession Nos. ML030550497 and ML030550529)

13. U.S. Nuclear Regulatory Commission, NUREG-1437, Supplement 17, "Generic Environmental Impact Statement for License Renewal of Nuclear Plants, Supplement 17, Regarding Dresden Nuclear Power Station, Units 2 and 3," June 2004 (ADAMS Accession No. ML041890266)

14. U.S. Nuclear Regulatory Commission, NUREG/CR-6174, PNL-9975, "Revised Analysis of Decommissioning for the Reference Boiling Water Reactor Power Station," dated July 1996 (ADAMS Accession No. ML14008A186)

15. U.S. Nuclear Regulatory Commission, NUREG-2157, Vol. 1, "Generic Environmental Impact Statement for Continued Storage of Spent Nuclear Fuel," September 2014 (ADAMS Accession No. ML14196A105)

16. Letter from Patrick R. Simpson (Exelon Generation Company, LLC) to U.S. Nuclear Regulatory Commission - "License Amendment Request - Proposed Defueled Technical Specifications and Revised License Conditions for Permanently Defueled Condition," dated October 29, 2020 (ADAMS Accession No. ML20303A313)

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