ML24365A224

Company - Three-Year Update to the Independent Spent Fuel Storage Installation Decommissioning Funding Plan

ML24365A224
Person / Time
Site:	Maine Yankee
Issue date:	12/10/2024
From:	Conry T Maine Yankee Atomic Power Co
To:	Office of Nuclear Material Safety and Safeguards
References
OMY-24-014
Download: ML24365A224 (1)

Text

Maine Yankee 321 Old Ferry Road, Wiscasset, Maine 04578 December 10, 2024 OMY-24-014 Re: 10 CFR 72.4, l O CFR 72.30, and 10 CFR 50.82(a)(7)

ATTN: Document Control Desk U.S. Nuclear Regulatory Commission Washington, DC 20555-0001 Maine Yankee Atomic Power Company Maine Yankee Independent Spent Fuel Storage Installation NRC License No. DPR-36 (NRC Docket No. 50-309) 7 2 - 0 3 D

Subject:

Three-Year Update to the Independent Spent Fuel Storage Installation Decommissioning Funding Plan Pursuant to the requirements of 10 CFR 72.30(c) and 10 CFR 72.4, Maine Yankee Atomic Power Company (Maine Yankee) is providing the three-year update to the Independent Spent Fuel Storage Installation (ISFSI) Decommissioning Funding Plan (DFP). Enclosure 1 updates the Maine Yankee ISFSI decommissioning cost estimate and the cost estimate for the management of irradiated fuel and Greater than Class C Waste submitted with the previous Maine Yankee ISFSI DFP on December 10, 2018 (Reference 1). It includes adjustments to account for changes in costs. The update does not include any adjustments for additional radiological contamination, because the extent of radioactive contamination at the Maine Yankee ISFSI remains unchanged.

10 CFR 72.30( c) defines specific events that must be considered in the subsequent updates.

Since the submittal of the updated Decommissioning Funding Plan for the ISFSI in December 2015:

1. No spills of radioactive material producing additional residual radioactivity in onsite subsurface material have occurred.

2. Facility modifications that affected the ISFSI, including those that were implemented within the licensed area, were assessed for impact.

3. There were no changes in authorized possession limits.

4. No active decommissioning has occurred, thus, there have not been any actual remediation costs that exceed the previous cost estimate.

In addition, Maine Yankee complies with the requirements of 10 CFR 72.30(b)(l) through (b)(6), as follows.

10 CFR 72.30(b)(l) requires the licensee to provide "information on how reasonable assurance will be provided that funds will be available to decommission the ISFSI." Maine Yankee has established accounts within its Nuclear Decommissioning Trust (NDT) entitled, "ISFSI Rad Coho" and "ISFSI Rad Mellon," that segregate the funds for decommissioning of the ISFSI from NM5S16 NMSS

Maine Yankee Atomic Power Company OMY-24-014/December 10, 2024/Page 2 the larger balance of funds for ongoing management of irradiated fuel and GTCC waste held in the NDT. Currently, the trust has sufficient funds to meet the revised DCE for the Maine Yankee ISFSI.

10 CFR 72.30(b)(2) requires the licensee to provide a detailed cost estimate for decommissioning. Enclosure I provides a revised DCE for the Maine Yankee ISFSI that:

1. Utilizes an independent contractor to perform the decommissioning activities in accordance with IO CFR 72.30(b )(2)(i);

2. Includes an adequate contingency factor in accordance with 10 CFR 72.30(b )(2)(ii); and

3. Includes the cost of meeting the criteria for unrestricted release in accordance with 10 CFR 72.30(b)(2)(iii).

In addition, the revised Maine Yankee ISFSI DCE specifically considered the effects of the events described in 10 CFR 72.30( c) on the costs of decommissioning and the extent of contamination. The revised Maine Yankee ISFSI DCE estimates the total cost to decommission the Maine Yankee ISFSI to be $7.808 million in 2024 dollars for radiological decommissioning and $13.846 million in 2024 dollars for ISFSI site restoration that includes the additional costs for non-radiological decommissioning and site restoration costs.

10 CFR 72.30(b )(3) requires the licensee to identify and justify the key assumptions contained in the DCE. Enclosure l provides the revised DCE for the Maine Yankee ISFSI, including the key assumptions and the justification for their use.

10 CFR 72.30(b )( 4) requires the licensee to provide a description of the method of assuring funds for decommissioning from 10 CFR 72.30(e), including means for adjusting cost estimates and associated funding levels periodically over the life of the facility. Maine Yankee will periodically reassess the decommissioning cost estimate in accordance with 10 CFR 72.30(c).

On a periodic basis, Maine Yankee will submit rate cases to Federal Energy Regulatory Commission (FERC) that will include revised cost estimates for decommissioning and the management of irradiated fuel and GTCC waste. If necessary, additional funds may be recovered from the purchasers.

Maine Yankee has successfully litigated several breaches of contract damages claims against the Department of Energy (DOE) for failure to begin the removal of spent nuclear fuel (SNF) and GTCC waste from the site in 1998. Additional damages claims against the DOE relating to the government's breach of contract are expected to continue as long as the irradiated fuel and GTCC waste remain on site.

Annually, Maine Yankee submits the reports required by 10 CFR 50.75(f)(2),

10 CFR 50.82(a)(8)(v) and 10 CFR 50.82(a)(8)(vii) to establish how it satisfies the obligations defined in those regulations regarding the assurance of decommissioning funding and the status of funding for the management of irradiated fuel.

10 CFR 72.30(b )(5) requires the licensee to define the volume of onsite subsurface material containing residual radioactivity that will require remediation to meet the criteria for license

Maine Yankee Atomic Power Company OMY-24-014/December 10, 2024/Page 3 termination. No subsurface material is assumed to require remediation regarding radionuclides.

This is justified because:

1. The ISFSI area was confirmed to be clean of radiological contaminants prior to the construction of the ISFSI.

2. The ISFSI area will be maintained clean of loose radiological contaminants during the storage period.

3. The irradiated fuel and GTCC waste are stored in sealed canisters.

4. Nuclear activation of a limited number of Vertical Concrete Casks (VCCs) and VCCs liners are anticipated; the activation products will remain fixed during the storage period.

5. If contamination of subsurface occurs during decommissioning activities, the contamination is expected to remain below the decommissioning criteria of25 millirem per year Total Effective Dose Equivalent.

In addition, the site will meet the remediation standards established by the State of Maine.

IO CFR 72.30(b )(6) requires a certification that financial assurance for decommissioning has been provided in the amount of the cost estimate for decommissioning. Enclosure 2 provides the certification of financial assurance.

In addition, Enclosure 3 provides an estimate of the total costs associated with the Maine Yankee ISFSI for the management of irradiated fuel and GTCC waste at the Maine Yankee ISFSI through 2043.

As applicable, a summary of the revised DCE and the cost estimate for the management of irradiated fuel and GTCC waste at the Maine Yankee ISFSI will be incorporated into the Post-Shutdown Decommissioning Activities Report (PSDAR) and the License Termination Plan (L TP) in calendar year 2025. This submittal serves as the notification required by 10 CFR 50.82(a)(7).

If you have any questions, please do not hesitate to contact me at (508) 612-3322.

Maine Yankee Atomic Power Company OMY-24-014/December 10, 2024/Page 4

Enclosures:

1. Decommissioning Study of the Maine Yankee Independent Spent Fuel Storage Installation

2. Certification of Financial Assurance

3. Total Costs Associated with the Maine Yankee ISFSI, including Cost Estimate for Managing Irradiated Fuel and GTCC Waste

Reference:

1. Letter from C. Pizzella (Maine Yankee) to Document Control Desk (NRC), Independent Spent Fuel Storage Installation Decommissioning Funding Plan, dated December 10, 2021 (OMY-21-013) cc:

R. Lorson, NRC Region I Administrator A. Dimitriadis, Chief, Decommissioning Branch, NRC, Region I Y. Diaz-Sanabria, Chief, Division of Fuel Management, Storage and Transportation Licensing Branch J. Hyland, State of Maine A. Landry, Deputy Public Advocate, Maine Office of the Public Advocate S. Most, Sr. Assistant to the Public Advocate, Maine Office of the Public Advocate L. Raber, Staff Attorney, ME PUC

ENCLOSURE 1 TO OMY-24-014 DECOMMISSIONING STUDY OF THE MAINEY ANKEE INDEPENDENT SPENT FUEL STORAGE INSTALLATION

Mr. Todd Smith Mr. Stan Day The Yankees Companies 362 lnjun Hollow Road East Hampton, CT 06424 TLG Services, LLC 148 New Milford Rd. East Bridgewater, CT 06752 (860) 355-2300 www.tlgservices.com July 19, 2024 Y03-1833-001

Subject:

2024 Decommissioning Cost Estimates for the Connecticut Yankee Atomic Power Company, Maine Yankee Atomic Power Company, and the Yankee Atomic Electric Company

Dear Mr. Smith:

Attached please find TLG's Final copies of the 2024 cost estimates for decommissioning the Connecticut Yankee Atomic Power Company, Maine Yankee Atomic Power Company, and the Yankee Atomic Electric Company ISFSls.

If you have any questions, please call me at (716) 432-8659.

Attachments:

2024 Connecticut Yankee ISFSI Letter 2024 Maine Yankee ISFSI Letter 2024 Yankee Rowe ISFSI Letter cc:

Lori Glander Angela Bouton Rich Threlkeld John Carlson Sincerely, TLG Services, LLC Adam Kaczmarek Sr. Manager, Decommissioning

Maine Yankee Atomic Power Company Maine Yankee ISFSI Page 1 of 10 10 CFR 72.30 ISFSI Decommissioning Cost Estimate

1.

Background and Introduction The Nuclear Regulatory Commission (NRC) issued its final rule on Decommissioning Planning on June 17, 2011,[11 with the rule becoming effective on December 17, 2012. Subpart 72.30, "Financial assurance and recordkeeping for decommissioning," requires that each holder of, or applicant for, a license under this part must submit for NRC review and approval a decommissioning funding plan that contains information on how reasonable assurance will be provided that funds will be available to decommission the Independent Spent Fuel Storage Installation (ISFSI).

In accordance with the rule, this letter provides a detailed cost estimate for decommissioning the Maine Yankee (MY) Independent Spent Fuel Storage Installation (ISFSI) in an amount reflecting:

1. The work is performed by an independent contractor;

2. An adequate contingency factor; and

3. Release of the facility and dry storage systems for unrestricted use, as specified in 10 CFR Part 20.1402 This letter also provides:

1. Identification of the key assumptions contained in the cost estimate; and

2. The volume of onsite subsurface material containing residual radioactivity, if any, that will require remediation to meet the criteria for license termination.

2.

Spent Fuel Management Strategy Maine Yankee (MY) was successfully decommissioned between 1997 and 2005.

During decommissioning all 1,434 spent fuel assemblies were transferred from the spent fuel pool to 60 spent fuel storage casks. In addition, 4 GTCC casks containing segmented sections of the reactor internals are stored on the spent fuel storage pad. The ISFSI is operated under a Part 50 General License.

1 U.S. Code of Federal Regulations, Title 10, Parts 20, 30, 40, 50, 70 and 72 "Decommissioning Planning," Nuclear Regulatory Commission, Federal Register Volume 76, Number 117 (p 35512 et seq.), June 17, 2011 TLG Services, LLC

Maine Yankee Atomic Power Company Maine Yankee ISFSI Page 2of 10 Completion of the ISFSI decommissioning process is dependent upon the DOE's ability to remove spent fuel from the site. DOE's repository program assumes that spent fuel allocations will be accepted for disposal from the nation's commercial nuclear plants, with limited exceptions, in the order (the "queue") in which it was discharged from the reactorJ2l

3.

ISFSI Decommissioning Strategy At the conclusion of the DOE spent fuel transfer process the ISFSI will be promptly decommissioned (similar to the power reactor DECON alternative) by removing and disposing of residual radioactivity and verifying that remaining materials satisfy NRC and the State of Maine release criteria.

4.

ISFSI Description The MY ISFSI is located on approximately 11 acres of the site. The ISFSI consists of 60 dry storage casks containing 1,434 spent nuclear fuel assemblies used during operations. The NAC-UMS fuel storage and transport canister system was chosen by MY and is licensed by the NRC for both storage and transportation. The NAC-UMS system consists of a multi-purpose spent fuel storage canister and a vertical concrete and steel overpack. Each vertical concrete cask has a two-and-a-half-inch steel liner surrounded by approximately 28 inches of reinforced concrete. Construction of the concrete storage pad and vertical concrete and steel storage was completed during decommissioning. Transferring the spent fuel from the spent fuel pool to the storage casks was completed in March of 2004.

In addition to the 60 spent fuel storage casks there are 4 casks containing segmented sections of the reactor internals classified as Greater than Class C waste. The storage overpacks used for the GTCC canisters are not expected to have any interior contamination or residual activation and can be reused or disposed of by conventional means after a final status survey. The multi-purpose canisters will be transferred directly to the DOE. After removal of the UMS canisters, the overpacks will be surveyed and any found to have residual radioactivity due to some minor level of neutron-induced activation as a result of the long-term storage of the spent fuel will be removed as activated. The cost to dispose of residual radioactivity, and verify that the remaining facility and 2

U.S. Code of Federal Regulations, Title 10, Part 961.11, Article IV - Responsibilities of the Parties, B. DOE Responsibilities, 5.(a)... DOE shall issue an annual acceptance priority ranking for receipt of SNF and/or HLW at the DOE repository. This priority ranking shall be based on the age of SNF and/or HLW as calculated from the date of discharge of such materials from the civilian nuclear power reactor. The oldest fuel or waste will have the highest priority for acceptance, except as... "

TLG Services, LLC

Maine Yankee Atomic Power Company Maine Yankee ISFSI Page 3of 10 surrounding environs meet the NRC's radiological limits established for unrestricted use, form the basis of the ISFSI decommissioning estimate.

Table 1 provides the significant quantities and physical dimensions used as the basis in developing the ISFSI decommissioning estimate.

5.

Key Assumptions / Estimating Approach The decommissioning estimate is based on the configuration of the ISFSI expected after all spent fuel and GTCC material has been removed from the site. The configuration of the ISFSI is based on the assumptions associated with DOE's spent fuel acceptance, as previously described.

TLG does not expect the overpacks to have any interior or exterior radioactive surface contamination. Any neutron activation of the steel and concrete is expected to be extremely small. This assumption is adopted for this analysis.

The decommissioning estimate is based on the premise that the inner steel liners of some of the concrete and steel overpacks will contain low levels of neutron-induced residual radioactivity that would necessitate remediation at the time of decommissioning. As an allowance, 10 of the 60 overpacks are assumed to be affected, i.e., contain residual radioactivity. This is conservative, because the fuel had decayed in the spent fuel pool for a few years prior to being placed into dry storage. The overpacks will be segmented and packaged for disposal as low-level radioactive waste.

It is not expected that there will be any residual contamination to be left on the concrete ISFSI pad. It would be expected that this assumption would be confirmed as a result of good radiological practice of surveying potentially impacted areas after each spent fuel transfer campaign. It is assumed for this analysis that the ISFSI pad will not be contaminated. As such, only verification surveys are included for the pad in the decommissioning estimate. An allowance is also included for surveying any transfer equipment.

The subsurface material of the ISFSI site is not expected to contain any significant residual radioactivity that will require remediation to meet the criteria for license termination.

Decommissioning is assumed to be performed by an independent contractor.

As such, essentially all labor, equipment, and material costs are based on national averages, i.e., costs from national publications such as RSMeans Building Construction Cost Data (adjusted for regional variations), and laboratory service costs are based on vendor price lists. Those craft labor TLG Services, LLC

Maine Yankee Atomic Power Company Maine Yankee ISFSI Page 4of 10 positions are expected to be provided locally. MY, as licensee, will oversee the site activities.

The Utility oversight staff is assumed to be similar in size and configuration as it is currently.

The following buildings are disposed of as clean waste in a local landfill.

ISFSI Pad Remaining Overpacks Fencing ISFSI support systems Security operations building (SOB)

Miscellaneous pads Miscellaneous structures Nuisance fence Buried utilities Road in licensed area SOB electrical service Vehicle barriers Costs are reported in 2024 dollars. Costs do not include Maine sales tax.

Contingency has been added at an overall rate of 25%. This is consistent with the contingency evaluation criteria referenced by the NRC in NUREG-1757.!31 Contingency has been added to the Site Restoration costs at a rate of 25%.

The estimate is limited to costs necessary to terminate the ISFSI's NRC license and meet the §20.1402 criteria for unrestricted use. Disposition of released material and structures is outside the scope of the estimate.

The effects, if any, since the last submittal of the ISFSI decommissioning funding plan of the following events listed in 10 CFR 72.30(c)(l)-(4) have been specifically considered in the decommissioning cost estimate:

(1) Spills of radioactive material producing additional residual radioactivity in onsite subsurface material: There have been no spills at the ISFSI.

(2) Facility modifications: There have been no facility modifications in the past three years that affect the decommissioning cost estimate.

3 "Consolidated Decommissioning Guidance, Financial Assurance, Recordkeeping, and Timeliness," U.S. Nuclear Regulatory Commission's Office of Federal and State Materials and Environmental Management Programs, NUREG-1757, Volume 3, Revision 1, February 2012 TLG Services, LLC

Maine Yankee Atomic Power Company Maine Yankee ISFSI Page 5 of 10 (3) Changes in authorized possession limits: There are no changes in authorized possession limits that affect the decommissioning cost estimate.

(4) Actual remediation costs that exceed the previous cost estimate: No actual remediation costs have been incurred, therefore; actual remediation costs do not exceed the previous cost estimate.

6.

Cost Estimate The estimated cost to decommission the ISFSI and release the facility for unrestricted use is provided in Table 2. The cost has been organized into four phases, including:

• An initial planning phase - empty overpacks are characterized and the specifications and work procedures for the decontamination (liner removal) developed.

The remediation phase - residual radioactivity is removed, packaged in certified waste containers, transported to the low-level waste site, and disposed of at low-level waste.

The license termination phase - license termination surveys, independent surveys are completed, and an application for license termination submitted.

Site restoration - While not required by the NRC this estimate includes the cost to remove and dispose of all non-contaminated structures. A list of all structures included in this estimate is provided in Table 3.

In addition to the direct costs associated with a contractor providing the decommissioning services, the estimate also contains costs for the NRC (and NRC contractor), MY's oversight staff, site security (industrial), and other site operating costs.

For estimating purposes, it should be conservatively assumed that all expenditures will be incurred in the year following all spent fuel removal.

TLG Services, LLC

Maine Yankee Atomic Power Company Maine Yankee ISFSI Table 1 Page 6 of 10 Significant Quantities and Physical Dimensions ISFSI Pad Residual Item Length (ft)

Width (ft)

Radioactivity ISFSI Pads - 16 Total (dimensions are for each pad) 31 31 No ISFSI Overpack Item Value Notes (all dimensions are nominal)

MY-UMS Overall Height (inches) 225.9 Dimensions are nominal Overall Diameter (inches) 136.0 Dimensions are nominal Inside Diameter (inches) 74.5 Dimensions are nominal Inner Liner Thickness (inches) 2.50 Dimensions are nominal Quantity (total) 64 60 spent fuel + 4 GTCC Quantity (with residual radioactivity) 10 Total Surface Area of overpack interior with Residual 3,003 Radioactivity (square feet)

Low-Level Radioactive Waste (cubic feet) 23,991 Low-Level Radioactive Waste (buried density) 105 TLG Services, LLC

Maine Yankee Atomic Power Company Maine Yankee ISFSI Table 2 ISFSI Decommissioning Costs and Waste Volumes (Thousands of 2024 Dollars)

LLRW Removal Packaging Transport Disposal Other Total Costs Costs Costs Costs Costs Costs Activity Description Decommissioning Contractor Planning (characterization, 315 315 specs and procedures)

Decontamination (activated 253 283 660 1,196 liner and concrete removal)

License Termination 1,346 1,346 (radiological surveys)

Subtotal 253 283 660 1,661 2,857 Supporting Costs NRC and NRC Contractor 335 335 Fees and Costs Insurance 174 174 Property taxes 347 347 NRC Fees 268 268 Site O&M Cost 377 377 Security Staff Cost 333 333 TLG Services, LLC Burial Volume Class A (cubic feet) 23,991 23,991 Page 7 of 10 Oversight Craft and Manhours Contractor Manhours 1,048 1,685 7,828 9,513 1,048 1,153 11,625

Maine Yankee Atomic Power Company Maine Yankee ISFSI Table 2 (continued)

ISFSI Decommissioning Costs and Waste Volumes (Thousands of 2024 Dollars)

LLRW Removal Packaging Transport Disposal Other Total Costs Costs Costs Costs Costs Activitv Descriution Costs DOC Staff Cost 603 603 Utility Staff Cost 953 953 Subtotal 3,389 3,389 ISFSI Decontamination 253 283 660 5,050 6,246 Total (w/o contingency)

ISFSI Decontamination 316 354 825 6,313 7,808 Total (with 25%

contine:encv)

ISFSI Site Restoration Building removal - Inside fence Fencing (linear foot) 14 14 ISFSI Cask & Pad 1,347 401 1,748 Demolition and Removal ISFSI Support sytems 123 123 Building removal - Outside fence Miscellaneous Pads 20 20 Miscellaneous structures 108 108 Nuisance Fence 20 20 Removal of buried utilities 3

3 Removal of road in licensed 36 36 area TLG Services, LLC Burial Volume Class A (cubic feet) 23,991 23,991 Page 8of 10 Oversight Craft and Manhours Contractor Manhours 4,787 7,066 12,778 9,513 13,826 9,513 13,826 148 1,552 94 706 196 16 326

Maine Yankee Atomic Power Company Maine Yankee ISFSI Table 2 (continued)

ISFSI Decommissioning Costs and Waste Volumes (Thousands of 2024 Dollars)

LLRW Removal Packaging Transport Disposal Other Total Costs Costs Costs Costs Costs Activitv Descriution Costs SOB Electrical service 0.3 0.3 Security Operations 310 310 Building Vehicle Barriers 1

1 Construction Debris 195 195 Site Restoration 8

8 Subtotal 1,990 596 2,586 Supporting Costs NRC and NRC Contractor 26 26 Fees and Costs Property taxes 173 173 Site O&M Cost 188 188 Security Staff Cost 167 167 DOC Staff Cost 302 302 Utility Staff Cost 476 476 Severance 912 912 Subtotal 2,244 2,244 ISFSI Site Restoration Total 1,990 2,840 4,830 (w/o contingency)

ISFSI Site Restoration Total 2,488 3,550 6,038 (with 25% contingency)

Total (w/o contingency) 2,243 283 660 7,890 11,077 Total (with contingency) 2,804 354 825 9,863 13,846 TLG Services, LLC Burial Volume Class A (cubic feet) 23,991 23,991 Page 9of 10 Oversight Craft and Manhours Contractor Manhours 2

2,584 4

32 5,661 160 5,813 2,393 3,533 11,899 5,661 11,899 5,661 11,899 15,174 25,725 15,174 25,725

Maine Yankee Atomic Power Company Maine Yankee ISFSI Table 3 ISFSI Decommissioning - Structures Included Contaminated Removal Cask inner liner Cask lid Cask base & misc. Internal fixtures VCC concrete Clean Removal Non-activated overpacks ISFSI Concrete Pad Remove fencing Ginear foot)

ISFSI support systems Miscellaneous pads Miscellaneous structures Nuisance fence Removal of buried utilities Removal of road in licensed area Security operations building (SOB)

SOB electrical service Vehicle barriers TLG Services, LLC Page 10 of 10

ENCLOSURE 2 TO OMY-24-014 CERTIFICATION OF FINANCIAL ASSURANCE

CERTIFICATION OF FINANCIAL ASSURANCE NRC Licensee:

Maine Yankee Atomic Power Company Maine Yankee Independent Spent Fuel Storage Installation NRC License No. DPR-36 (NRC Docket No. 72-30) 321 Old Ferry Road Wiscasset, ME 04578-4922 Issued to: U.S. Nuclear Regulatory Commission Certification:

I hereby certify that Maine Yankee Atomic Power Company is the licensee for the Maine Yankee Independent Spent Fuel Storage Installation (Maine Yankee ISFSI) and that I, the undersigned, am authorized to provide this Certification of Financial Assurance with respect to the radiological decommissioning of the Maine Yankee ISFSI.

During the operation of this ISFSI, spent nuclear fuel and Greater than Class C waste will be stored at the Maine Yankee ISFSI in storage casks licensed under 10 CFR 72. Pursuant to contracts with the Department of Energy the spent fuel will ultimately be removed from the ISFSI location, and Maine Yankee will dispose of other radiological waste in accordance with NRC regulations, at which time the Maine Yankee ISFSI will be decommissioned in accordance with NRC regulations.

I further certify that financial assurance in an amount sufficient to fund Maine Yankee ISFSI radiological decommissioning at the time of such decommissioning has been provided, pursuant to 10 CFR 72.30, as described in Enclosure l to the letter to which this Certification is attached.

That radiological decommissioning funding assurance is premised on a site-specific decommissioning cost estimate and funding methodology described therein, in the amount of:

Maine Yankee ISFSI

$7.808 million (in 2024 dollars, inclusive of contingency) y Conry aine Yankee Atomic Power Company Treasurer Phone (508) 612-3322 Date December 10, 2024 Corporate Seal

ENCLOSURE 3 TO OMY-24-014 TOTAL COSTS ASSOCIATED WITH THE HNP ISFSI, INCLUDING COST ESTIMATE FOR MANAGING IRRADIATED FUEL AND GTCC WASTE

Maine Yankee Atomic Power Company Irradiated Fuel & GTCC Waste Management and ISFSI Decom Estimate Represented in 2024 Dollars Row Labels Sumof2024 Sum of2025 Sum of 2026 Sum of 2027 Sum of 2028 Sum of 2029 Sum of2030 Sumof 2031 Sum of 2032 Contingency 662,682 618,567 613,821 604,290 611,774 571,857 577,628 593,375 578,661 Federal Excise Tax 4,500 4,500 4,500 4,500 4,500 4,500 4,500 4,500 4,500 Insurance 633,612 634,582 636,112 633,612 634,582 636,112 633,612 634,582 636,112 Labor - Non-Manual 3,529,434 3,368,376 3,138,046 3,090,662 3,067,022 3,012,940 3,027,102 3,008,450 2,975,348 Labor - Non-Manual Succession Planning 244,350 35,500 153,833 111,790 39,763 186,375 30,175 Labor - Security 3,850,000 3,900,000 3,900,000 3,900,000 3,900,000 3,900,000 3,900,000 3,900,000 3,900,000 Materials & Supplies 299,680 256,000 112,100 111,600 106,000 106,000 122,000 106,000 115,500 Miscellaneous 198,500 152,500 152,500 152,500 152,500 152,500 152,500 152,500 152,500 Outside Services - A&G 870,710 844,935 823,355 889,785 823,785 889,785 823,785 839,785 823,785 Outside Services - Fuel loading Outside Services - IAGE 110,000 60,000 710,000 160,000 60,000 60,000 60,000 60,000 60,000 Outside Services - ISFSI OP's 725,600 424,500 332,700 457,700 843,700 443,700 357,700 443,700 343,700 Outside Services - Legal 1,175,000 700,000 650,000 750,000 750,000 450,000 650,000 750,000 750,000 Outside Services - NON-RAD D&D of ISFSI Outside Services - RAD D&D of ISFSI Property Taxes 753,100 753,100 753,100 753,100 753,100 753,100 753,100 753,100 753,100 Regulatory Fees 905,500 830,500 830,500 830,500 830,500 830,500 830,500 830,500 830,500 Utilities 198,000 198,000 198,000 198,000 198,000 198,000 198,000 198,000 198,000 (blank) 2,024 2,025 2,026 2,027 2,028 2,029 2,030 2,031 2,032 Grand Total 13,918,342 12,991,935 12,892,260 12,692,109 12,849,281 12,011,023 12,132,220 12,462,898 12,153,913

Maine Yankee Atomic; Power Company lrradi11ed Fuel & GTCC Wasle Management Ind ISFSI Dooom Estimlt*

Reprasented in 2024 Dollars Row labtt*

Sumof20SS SUmof2034 Sumof 2035 S..m of 2031 8umof20S7 Sum of 203I 8um or 20:lt Contingency s10.ns 565,525 587,369 610,169 557,687 559,594 Fodenol Excise TIX 4,500 4,500 4,500 4,500 4,500 4,500 tnunnce 633,612 634,582 638,112 633,612 634,582 636,112 uobor - Non-Manual 2,948,820 2,964,674 2,941,082 2,953,682 2,941,082 2,953,682 labor. Non-Manual Succeaaion Planning 58,187 22,500 labor* Security 3,900,000 3,900,000 3,900,000 3,900,000 3,900,000 3,900,000 Materials & SUpplies 186,000 108,000 106,000 106,000 218,000 106,000 Mlscellanaous 152,500 152,500 152,500 152,500 152,500 152,500 Ou1sldeS.rvice1 - A&G 839,785 923,785 839,785 823,785 839,785 823,765 Outlide Services

• Fuel Lolldlng Outside 5ervice1

• IAGE 60,000 60,000 80,000 760,000 110,000 60,000 OU1sida S...tcel - ISFSI OPs 457,700 343,700 423,700 337,700 123,700 123,700 OutlideSetvicel - Ltgal 450,000 850,000 750,000 750,000 450,000 650,000 Outllde 6emces

• NON-RAO D&D ol lSFSI Outlkte 6etvicft

• RAO D&D ol lSFSI Property Taxes 753,100 753,100 753,100 753,100 753,100 753,100 Ragulalo<y Feet 830,500 980,500 900,500 830,500 830,500 830,500 Ulil11iH 198,000 198,000 198,000 198,000 198,000 198,000 (blank) 2,033 2,034 2,035 2,036 2,037 2,036 GnndTotal 11,987,271 12,ZW,Ol7 12,SST,203 12,815,584 11,71M7S 11,753,511 (AJ

• Sour.a 2014 FERC Drtlt Budgl1

• Yoon 2024

• 2044 NOil 1' Tho col1 of management ol irrach!ed fuel end GTCC waste is calculated H followo:

207,410,803 (5,3n,500J

!5,935,0001 256,098,303 Nole 2 Tht cost of RAO Ind NON-RAO D&D of the ISFSI In 202 doh!s II provided In the cokom labeled "&an of 2042 & 2043* lo from TLG 2024 cost ---

Note 3: This summary combines MY'I 2024 OraR FERC Rat, Case wilh tho TLG Se1v1c:a 2024 RAD and NON-Rid ISFSI Decom Cost Eslimlto.

567,839 4,500 633,812 2,941,082 3,900,000 106,000 152,500 689,765 60,000 137,700 750,000 753,100 830,500 198,000 2,039 11,128,157 Sum of Tot.ti Sum of 2040 Sum of 2041 SUmof2042 sumof2041 Sumof2044 2024-21144 5113,267 549,7&1 1,420,753 808,110 845,809 13,659,287 4,500 4,500 4,500 4,500 4,500 94,500 834,582 030,112 033,812 834,582 1,047,570 13,741,000 2,953,682 2,941,082 2,601,035 2,601,035 2,601,035 82,559,353 883,453 3,900,000 3,900,000 3,900,000 500,000 500,000 75,050,000 106,000 106,000 106,000 35,000 30,000 2,849,680 152,500 152,500 152,500 96,500 98,500 3,136,500 823,785 839,785 768,765 825,165 680,185 $

17,550,930 3,025,600 3,025,600 60,000 60,000 60,000 60,000 60,000 2,810,000 123,700 123,700 123,700 138,700 11,200 6,841,llOO 725,000 450,000 650,000 750,000 2,000,000 15,850,000 4,917,352 s

4,917,352 2021 TlG 1,932,790 3,924,149 5,856,939 20l1 nG 753,100 753,100 753,100 753,100 378,100 s 15,440,100 2021 TtG 830,500 830,500 1,230,500 1,480,500 1,015,000 $

19,010,000 198,000 198,000 198,000 200,000 25,000 s 3,817,000 2,040 2,041 2,042 2,043 2,044 s 11,830,151 11,547,0M 17,stS,117 17,732,7st t~,NS $ 2",872,514 (A}

(4,917,352) 2021 TlG 2024S (1,932,790) 2021 TlG 2024S (3,924,149) 2021 TlG 2024S 5,3TT,500 2024 TlG 1,958,550 2024 TlG 3,978,450 2024 TLG I 2111410110, oo