NG-24-0001, 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report and Independent Spent Fuel Storage Installation (ISFSI) Decommissioning Financial Assurance Update

2024 Annual Decommissioning and Spent Fuel Management Funding Status Report and Independent Spent Fuel Storage Installation (ISFSI) Decommissioning Financial Assurance Update

ML24071A056
Person / Time
Site:	Duane Arnold, Maine Yankee
Issue date:	03/06/2024
From:	Both J NextEra Energy Duane Arnold
To:	Document Control Desk, Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
NG-24-0001
Download: ML24071A056 (1)

Text

March 6, 2024 Nuclear Regulatory Commission Attn: Document Control Desk Washington, DC 20555-0001 Duane Arnold Energy Center Docket No. 50-331 Renewed Facility Operating License No DPR-49 Duane Arnold Energy Center Independent Spent Fuel Storage Installation NRC Docket No.72-030 NEXTeraM ENERGY~

NG-24-0001 10 CFR 50.75(f)(1) 10 CFR 50.82(a)(8)(v) 10 CFR 72.30(c)

Subject:

Duane Arnold Energy Center, 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report and Independent Spent Fuel Storage Installation (ISFSI) Decommissioning Financial Assurance Update

References:

1) Letter, Curtland (NEDA) to U.S. NRC, "Certification of Permanent Cessation of Power Operations," NG-20-0074, dated August 27, 2020 (ML20240A067)

2) Letter, Curtland (NEDA) to U.S. NRC, "Certification of Permanent Removal of Fuel from the Reactor Vessel for Duane Arnold Energy Center," NG-20-0090, dated October 12, 2020 (ML20286A317)

3) Letter, Curtland (NEDA) to U.S. NRC, "Post Shutdown Decommissioning Activities Report," NG-20-0027, dated April 2, 2020 (ML20094F603)

4) Letter, Hansen (NEDA) to U.S. NRC, "Update to Spent Fuel Management Plan Pursuant to 10 CFR 50.54(bb)," NG-20-0078, dated January 13, 2021 (ML21014A455)

5) Letter, Wall (NRC) to D. Moul (NEDA), "Duane Arnold Energy Center - Request for Exemption from 10 CFR 50.82(a)(8)(i)(A) and Section 75(h)(1)(iv)," dated August 12, 2020 (ML20171A627, ML20171A626)

In accordance with 10 CFR 50. 75(f){1 ), 10 CFR 50.82(a)(8)(v), 10 CFR 50.82(a)(8)(vii), NextEra Energy Duane Arnold, LLC (NEDA) submits the annual status of decommissioning funding, status of funding for managing irradiated fuel, and the financial assurance status report for the Duane Arnold Energy Center (DAEC).

In accordance with 10 CFR 72.30(c), NEDA submits the ISFSI Decommissioning Financial Assurance Update for the DAEC. NEDA, Central Iowa Power Cooperative, and Corn Belt Power Cooperative own the Duane Arnold Energy Center. The update provides the ISFSI financial assurance for all three owners.

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NextEra Energy Duane Arnold, LLC, 3277 DAEC Road, Palo, IA 52324

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NextEra Duane Arnold, LLC I Duane Arnold Energy Center NG-24-0001 Page 2 of 2 In References 1 and 2, DAEC certified permanent cessation of power operation and permanent removal of fuel from the reactor vessel for DAEC. In Reference 3, DAEC submitted its Post-Shutdown Decommissioning Activities Report (PSDAR) containing a site-specific Decommissioning Cost Estimate (DCE) pursuant to 10 CFR 50.82(a)(4)(i) and 10 CFR 50.82(a)(8)(iii). In Reference 4, NEDA submitted a spent fuel management plan pursuant to 10 CFR 50.54(bb). In Reference 5, the NRC granted an exemption allowing NEDA to fund spent fuel management and site restoration costs from its Nuclear Decommissioning Trust. provides the 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report. Enclosure 2 provides the ISFSI Decommissioning Financial Assurance Update.

This letter contains no new commitments and makes no revisions to existing commitments.

If you should have any questions about the enclosed reports, please contact Tracy Weaver at (319) 851-7250.

Respectfully,

~BL--

Justin Both Decommissioning Director, Duane Arnold Energy Center NextEra Energy Duane Arnold, LLC

Enclosures:

As stated cc:

Regional Administrator, USNRC, Region Ill Project Manager, USNRC, Duane Arnold Energy Center Inspector, USNRC, Duane Arnold Energy Center State of Iowa Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report As required by 10 CFR 50.75(£)(1) and 10 CFR 50.82(a)(8), Duane Arnold Energy Center (DAEC) reports the following information:

A. Current Decommissioning Cost Estimate (License Termination, Spent Fuel Management, and Site Restoration)

As required by 10 CFR 50.82, DAEC completed a site-specific Decommissioning Cost Estimate (DCE), prepared by Energy Solutions LLC. The study was performed using the SAFSTOR decommissioning method. The DCE included expenses anticipated to be incurred for license termination activities (radiological remediation), interim spent fuel storage, and non-radiological site restoration activities. Based on an update to this DCE, the total estimated cost to decommission DAEC for the remaining period of 2024-2080 in 2023 dollars is $1,007,934,811. 1 Of that total cost estimate, the current site-specific cost estimate for license termination expenses of Duane Arnold Energy Center is

$726,436,093. The current estimate of spent fuel management costs is $240,626,718. The current estimate for non-radiological site restoration is $38,638,000. The current estimate of Independent Spent Fuel Storage Installation (ISFSI) demolition and decommissioning (D&D) costs is $2,234,000.

B. Funding Balance for License Termination Because DAEC is jointly owned among NextEra Energy Duane Arnold, LLC (NEDA),

Central Iowa Power Cooperative (CIPCO), and Corn Belt Power Cooperative (Corn Belt), each Joint Owner (NEDA, CIPCO, and Corn Belt) maintains nuclear decommissioning trust(s) respective to their undivided interest ownership share.

The total balance available in NRC-jurisdictional nuclear decommissioning trusts (NDTs) for DAEC as of December 31, 2023 was $606,725,712, broken out as follows.

Licensee Trust Balance as of 12/31/23

($Thousands)

Duane Arnold-NextEra 480,722 Duane Arnold - CIPCO 83,636 Duane Arnold - Corn Belt 42,368 C. Funding Balance for Spent Fuel Management In accordance with the exemption granted by the NRC on August 12, 2020 (Reference 5),

withdrawals from NEDA's NDT are used for decommissioning, spent fuel management and non-radiological site restoration purposes.

1 The estimated cost from the updated DCE reflects updated assumptions and inflation. The cost is higher than the previous estimates primarily due to inflation.

Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report CIPCO and Corn Belt did not seek an exemption to allow use of their NDTs for spent fuel management activities. CIPCO and Corn Belt are not-for-profit electric cooperatives. CIPCO and Corn Belt maintain internal supplemental reserve funds, outside of their NDTs, the use of which are not legally restricted like an NDT, for asset retirement and other purposes. These funds are sufficient to pay for spent fuel management and may be supplemented by operational income, if necessary. The CIPCO and Corn Belt supplemental funds are not commingled with the NDTs used for license termination costs, and these funds are not included as funds for satisfying NRC minimum license termination obligations.

D. Annual Decommissioning Collections None.

E. Rates Used to Escalate Decommissioning Costs and Fund Balances The 2023 DCE is estimated as of2023 dollars in the provided Attachments B - C.

Anticipated NEDA, CIPCO, and Corn Belt NDT and supplemental fund balances incorporate a 2% annual real rate of return, consistent with the requirements of 10 CPR 50.75.

F. Contracts to Fund Decommissioning None.

G. Modification to Method of Providing Financial Assurance None.

H. Material Changes to Trust Agreements None.

I. Annual Report Conclusions Attachment A provides the amount spent on decommissioning, both cumulative and over the previous calendar year, the remaining balance of any decommissioning funds, an estimate of the costs to complete decommissioning work performed during the year, reflecting any difference between actual and estimated costs, in satisfaction of 10 CPR 50.82(a)(8)(v). Attachment A also provides the projected costs of managing spent fuel and the amount of funds accumulated to cover the cost of irradiated fuel, in satisfaction of 10 CPR 50.82(a)(8)(vii).

Attachment B provides the projected annual costs to decommission DAEC in 2023 dollars.

Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report Attachment C-1 compares the NEDA NDT balance, accounting for a 2% real rate of return, against the estimated costs for license termination, spent fuel management, and site restoration costs, demonstrating the NEDA NDT contains sufficient funds to cover license termination (50.82(a)(8)(v)) and spent fuel management (50.82(a)(8)(vii)) costs.

Attachment C-2 compares the CIPCO NDT balance, escalated at a 2% real rate of return, against the estimated costs for license termination, demonstrating the CIPCO NDT contains sufficient funds to cover license termination costs (50.82(a)(8)(v)).

Attachment C-3 compares the Corn Belt NDT balance, escalated at a 2% real rate of return, against the estimated costs for license termination, demonstrating the Corn Belt NDT contains sufficient funds to cover license termination costs (50.82(a)(8)(v)).

Thus, considering the current NDT balances, anticipated growth in those balances over time, and anticipated future license termination costs, the Joint Owners' trust funds are expected to have adequate funds for completion of license termination activities.

Similarly, considering the NEDA NDT balance and the CIPCO and Corn Belt supplemental funds and other sources, the Joint Owners are expected to have adequate funds for spent fuel management activities.

Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report Decommissionino Trust Fund *Balances *so 75ifll1 50 s2ial

'Year Joiilt owner 2023 NEDA 2023 CIPCO 2023 Corn Belt Other Financial Assurance Methods Bemg Relied Upon 50.75[f)(1l None

• • ~'

• ---*-*-*****~ *-* -.,,;w

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. *~**"- -*

.Year.

License Termination 2019-2022 50,673,669 2023 3,408,059 Total 54,081,728 Prior Year Exoenditures Variance to Estimated Cost 50 82/al!BIMIBl

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Year:

• t..

ticerise*,rerminatio'n.

2023 Estimated 5,956,461 2023 Actual 3,408,059 Variance 2,548,402 Cumulative Withdrawals from Decommissionina Trusts 50.82/allSllvHAI

• Year '

• *,JointOwner

• iicense Termination' I

Through 12/31/2023 NEDA 35,331,269 $

Throuqh 12131/2023 CIPCO 10,544,974 $

Through 12131/2023 Corn Belt 5,119,734 $

Total Through 2023 50,995,977 $

Cost 50.82/al(BlM(Bl /lvnl{

.l.:.icense,Terminationi**

Decommissioning Funding Status Report Duane Arnold Energy Center ATTACHMENT A Summary Information as of December 31, 2023 10 CFR 50.82 (a) (8) (v)*(vii)

' Tvpe ofTrust Decommissioning Trust Decommissioning Trust Decommissioning Trust

• *~*

-~---.

Spent Fuel

,Site-Restoration,:

ISFSID&D.

91,400,055 $

1,110,728 $

5,767,073 (25,734) $

97,167,128 $

1,084,994 $

Spent Fuel Site Restoration* : *

• ISFSl:D&O Ir' 59,345,046 $

5,767,073 (25,734) $

53,577,973 $

25,734 $

Spent Fuel

' ** Site1Restoration

. < ISFSI D&D

• I'!.

67,558,450 $

758,575 $

67,558,450 $

758,575 $

Spent Fuel*.

Site Restoration.

• ISFSI D&D 240,626,718 $

38,638,000 $

F.uhd Baiance

.

• Coinm'ents 480,722,285 83,635,639 42,367,788

• • Total*

Comments 143,184,452 9,149,398 152,333,850

.Total Comments.

'*.*J

• C 65,301,507 9,149,398 56,152,109

.,'total'*

-,~Comments ',,

i *. <,'

103,648,294 10,544,974 5,119,734 119,313,002 Comments 1,007,934,811 Remaining decom costs from 2024 - 2080 in 2023 $

Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report Year 2024 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2024 - 2080 Total ATTACHMENT B Duane Arnold Energy Center Decommissioning Cost Estimate (100% Share)

Estimates in 2023 Dollars (Thousands)

License Spent Fuel Greenfield ISFSI D&D Termination 3,827 5,949 3,827 5,949 3,827 5,949 3,827 5,949 3,469 6,275 3,231 6,004 3,231 6,002 3,232 6,001 3,231 6,001 3,231 6,001 3,231 6,001 3,231 6,001 3,231 6,001 3,229 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3 148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,148 6,001 3,625 500 3,363 3,363 3,363 3,363 3,363 3,363 3,363 3,363 3,363 3,363 60,015 84,300 7

78,583 711 217,309 500 115,729 6,013 26,023 1,004 4,937 12,615 11 1,757 726,436 240,627 38,638 2,234 Total 2023$

9,776 9,776 9,776 9,776 9,745 9,235 9,234 9,233 9,232 9,232 9,232 9,232 9,232 9,230 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 9,149 4,125 3,363 3,363 3,363 3,363 3,363 3,363 3,363 3,363 3,363 3,363 60,015 84,307 79,294 217,809 148,769 17,563 1,757 1,007,935 Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report Year 2024<11 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2024 - 2080 Total ATTACHMENT C-1 NextEra Energy Duane Arnold, LLC (70% Share)

License Termination (50.82(a)(8)(v))

Spent Fuel (50.82(a)(8)(vii))

Estimates in 2023 Dollars (Thousands) / Balance with 2% Rate of Return NEDA Ownership I Balance Annual Fund Earninas License Spent Fuel Terrrination 2,679 4,165 2,679 4,165 2,679 4,165 2,679 4,165 2,428 4,393 2,262 4,202 2,262 4,202 2,262 4,201 2,262 4,201 2,262 4,201 2,262 4,201 2,262 4,201 2,262 4,201 2,260 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,204 4,201 2,538 350 2,354 2,354 2,354 2,354 2,354 2,354 2,354 2,354 2,354 2,354 42,011 59,010 55,008 152,116 81,010 4,209 3,456 1,230 508,505 168,439 70%

2.0%

Site Restoration 18,216 8,831 27,047 480,722 Nex!Era 70% Share of Costs Eligible from Decom Trust A

ISFSI D&D Total Beginning of Year Balance 6,843 480,722 6,843 480,508 6,843 483,275 6,843 486,097 6,821 488,975 6,464 491,933 6,464 495,308 6,463 498,750 6,463 502,263 6,463 505,845 6,463 509,499 6,463 513,227 6,463 517,029 6,461 520,907 6,404 524,864 6,404 528,957 6,404 533,132 6,404 537,390 6,404 541,734 6,404 546,164 6,404 550,683 6,404 555,293 6,404 559,994 6,404 564,790 6,404 569,681 6,404 574,671 6,404 579,760 6,404 584,951 6,404 590,246 6,404 595,646 6,404 601,155 6,404 606,774 6,404 612,505 6,404 618,351 6,404 624,314 6,404 630,396 6,404 636,599 6,404 642,927 6,404 649,381 2,888 655,965 2,354 666,196 2,354 677,166 2,354 688,355 2,354 699,768 2,354 711,410 2,354 723,284 2,354 735,396 2,354 747,750 2,354 760,351 2,354 773,204 42,011 786,314 5

59,015 760,029 498 55,506 716,215 350 152,466 675,033 703 104,138 536,067 8

12,294 442,651 1,230 439,209 1,564 705,554 B

C Annual NDT WHhdrawals Earnings (9,829) 9,614 (6,843) 9,610 (6,843) 9,665 (6,843' 9,722 (6,821' 9,780 (6,464) 9,839 (6,464) 9,906 (6,463) 9,975 (6,463) 10,045 (6,463) 10,117 (6,463) 10,190 (6,463) 10,265 (6,463) 10,341 (6,461) 10,418 (6,404) 10,497 (6,404) 10,579 (6,404) 10,663 (6,404) 10,748 (6,404) 10,835 (6,404) 10,923 (6,404) 11,014 (6,404) 11,106 (6,404) 11,200 (6,404) 11,296 (6,404) 11,394 (6,404) 11,493 (6,404) 11,595 (6,404) 11,699 (6,404) 11,805 (6,404) 11,913 (6,404) 12,023 (6,404) 12,135 (6,404' 12,250 (6,4041 12,367 (6,404' 12,486

/6,404\\

12,608 (6,404) 12,732 (6,4041 12,859 (6,404' 12,988 (2,888 13,119 (2,354) 13,324 (2,354' 13,543 (2,3541 13,767 (2,354) 13,995 (2,3541 14,228 (2,354' 14,466 (2,3541 14,708 (2,354) 14,955 (2,354) 15,207 (2,354) 15,464 (42,011) 15,726 (59,015 15,201

/55,506\\

14,324 (152,4661 13,501 (104,138' 10,721 (12,294) 8,853 (1,230' 8,784 1 2024 NDT withdrawal includes $2,985 of expenses that were not reimbursed during prior periods.

=A+B+C End of Year NDT Balance 480,508 483,275 486,097 488,975 491,933 495,308 498,750 502,263 505,845 509,499 513,227 517,029 520,907 524,864 528,957 533,132 537,390 541,734 546,164 550,683 555,293 559,994 564,790 569,681 574,671 579,760 584,951 590,246 595,646 601,155 606,774 612,505 618,351 624,314 630,396 636,599 642,927 649,381 655,965 666,196 677,166 688,355 699,768 711,410 723,284 735,396 747,750 760,351 773,204 786,314 760,029 716,215 675,033 536,067 442,651 439,209 446,764 Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report Year 2024(2) 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2024

• 2080 Total ATTACHMENT C-2 CIPCO (20% Share)

License Termination (50.82(a)(8)(v))

Estimates in 2023 Dollars (Thousands) / Balance with 2% Real Rate of Return CIPCO Ownership I Balance Annual Fund EarninAs License ISFSI D&D Termination 765 765 765 765 694 646 646 646 646 646 646 646 646 646 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 630 725 673 673 673 673 673 673 673 673 673 673 12,003 16,860 1

15,717 142 43462 100 23,146 201 987 2

351 145,287 447 20%

2.0%

83,636 CIPCO 20% Share of Costs Eligible from Decom Trust A

B Total Beginning of Yoar Balance Withdrawals 765 83636

{1,037) 765 84,272 (765) 765 85,192 (765) 765 86,130 (765) 694 87087 (694) 646 88135 (646) 646 89,252 (646) 646 90,391 (646) 646 91 552 (646) 646 92 737 (646) 646 93 945 (646) 646 95,178 (646) 646 96,435 (646) 646 97,718 (646) 630 99,026 (630) 630 100,377 (630) 630 101,755 (630) 630 103,161 (630) 630 104 594 (630) 630 106057 (630) 630 107,548 (630) 630 109,070 (630 630 110 622

~

630 112,204 630 113,819

/630 630 115,466 (630 630 117145 (630) 630 118,859 (630) 630 120,606 (630) 630 122,389 (630\\

630 124,207

/630) 630 126,062

/630) 630 127 953

/630\\

630 129 883

/630) 630 131,851

/630\\

630 133,858

/630\\

630 135,906 1630\\

630 137,994

/630\\

630 140 125

/630\\

725 142,298 1725) f\\7~

144,419

/673) 673 146,634 (673\\

673 148,895 (673\\

673 151,200 (673) 673 153 551 (673\\

673 155,950 (673) 673 158 396 (673) 673 160 891 (673) 673 163 437 (673) 673 166,033 (673 12,003 168,681 (1? OO~'

16 861 160,052 (16 861\\

15,859 146,391 (15,859) 43,562 133,460 143,562) 23347 92,567 123,347\\

990 71,072 (990\\

351 71,504 (351) 145,734 C

Annual NOT Earnings 1,673 1,685 1 704 1,723 1,742 1763 1 785 1 808 1,831 1 855 1,879 1 904 1,929 1,954 1,981 2,008 2035 2,063 2,092 2,121 2 151 2 181 2,212 2,244 2,276 2 309 2,343 2,377 2412 2,448 2 484 2,521 2,559 2,598 2,637 2 677 2 718 2 760 2,802 2,846 2,888 2,933 2,978 3 024 3071 3 119 3,168 3,218 3,269 3 321 3,374 3,201 2,928 2,669 1,851 1,421 1,430 2 2024 NDT withdrawal includes $271 of expenses that were not reimbursed during prior periods.

=A+B+C End of Year NOT Balance 84,272 85192 86,130 87 087 88,135 89,252 90,391 91,552 92,737 93,945 95,178 96,435 97718 99,026 100 377 101,755 103,161 104,594 106,057 107,548 109 070 110622 112 204 113 819 115,466 117,145 118,859 120,606 122,389 124,207 126,062 127,953 129,883 131,851 133,858 135,906 137,994 140,125 142 298 144,419 146 634 148,895 151,200 163,551 155,950 158,396 160,891 163,437 166 033 168 681 160,052 146,391 133,460 92,567 71,072 71 504 72,583 Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report Year 2024<3) 2025 2026 2027 2028 2029 2030 2031 2032 2033 2034 2035 2036 2037 2038 2039 2040 2041 2042 2043 2044 2045 2046 2047 2048 2049 2050 2051 2052 2053 2054 2055 2056 2057 2058 2059 2060 2061 2062 2063 2064 2065 2066 2067 2068 2069 2070 2071 2072 2073 2074 2075 2076 2077 2078 2079 2080 2024 - 2080 Total ATTACHMENT C-3 Corn Belt (10% Share)

License Termination (50.82(a)(8)(v))

Estimates in 2023 Dollars (Thousands) / Balance with 2% Real Rate of Return CB Ownership / Balance Annual Fund Earninqs License ISFSI O&O Termination 383 383 383 383 347 323 323 323 323 323 323 323 323 323 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 315 363 336 336 336 336 336 336 336 336 336 336 6,002 8,430 1

7,858 71 21,731 50 11,573 100 494 1

176 72,644 223 10%

2.0%

42,368 Corn Belt 10% Share of Costs Eligible from Oecom Trust A

B Total Beginning of Year Withdrawals Balance 383 42,368 (671) 383 42,544 (383) 383 43,012 (383) 383 43,490 (383) 347 43,977 (347) 323 44,510 (323) 323 45,077 (323) 323 45,655 (323) 323 46,245 (323) 323 46,847 (323) 323 47,460

/323) 323 48,087 (323) 323 48,725 (323) 323 49,377 (323) 315 50,041

/315) 315 50,727 1315) 315 51,427

/315) 315 52,141 (315) 315 52,869

/315) 315 53,611 (315) 315 54,369 (315) 315 55,141 (315) 315 55,929 (315) 315 56,733 (315) 315 57,553 (315) 315 58,389 (315) 315 59,242

/315) 315 60,112

/315) 315 61,000 (315) 315 61,905 (315) 315 62,828

/315) 315 63,770

/315) 315 64,731 (315) 315 65,711 (315) 315 66,710 (315) 315 67,730

/315) 315 68,769

/315) 315 69,830 (315) 315 70,912 (315) 363 72,015 (363) 336 73,093 (336) 336 74,219 (336) 336 75,367 (336) 336 76,538

/336) 336 77,732

/336) 336 78,951

/336) 336 80,193

/336) 336 81,461

/336) 336 82,754

/336) 336 84,073 (336) 6,002 85,418 (6,002) 8,431 81,125 (8,431) 7,929 74,316 (7,929) 21,781 67,873 121,781) 11,673 47,450 111,673) 495 36,725 (495) 176 36,965 (176) 72,867 C

Annual NOT Earnings 847 851 860 870 880 890 902 913 925 937 949 962 975 988 1,001 1,015 1,029 1,043 1,057 1,072 1,087 1,103 1,119 1,135 1,151 1,168 1,185 1,202 1,220 1,238 1,257 1,275 1,295 1,314 1,334 1,355 1,375 1,397 1,418 1,440 1,462 1,484 1,507 1,531 1,555 1,579 1,604 1,629 1,655 1,681 1,708 1,622 1,486 1,357 949 735 739 3 2024 NDT withdrawal includes $288 of expenses that were not reimbursed during prior periods.

=A+B+C End of Year NOT Balance 42,544 43,012 43,490 43,977 44,510 45,077 45,655 46,245 46,847 47,460 48,087 48,725 49,377 50,041 50,727 51,427 52,141 52,869 53,611 54,369 55,141 55,929 56,733 57,553 58,389 59,242 60,112 61,000 61,905 62,828 63,770 64,731 65,711 66,710 67,730 68,769 69,830 70,912 72,015 73,093 74,219 75,367 76,538 77,732 78,951 80,193 81,461 82,754 84,073 85,418 81,125 74,316 67,873 47,450 36,725 36,965 37,529 Duane Arnold Energy Center 2024 Annual Decommissioning and Spent Fuel Management Funding Status Report ATTACHMENT D(4l Duane Arnold Energy Center 2023 Decommissioning Cost Actual Expenses (100% Share)

(dollars in thousands)

,,, IJecommissioning Expense L T4 Completion of SAFSTOR Preparations Total Payroll, Compensation & Labor Ohs Contractors & Professional Sen.ices Employee Related Expenses Licenses, Permits & Fees Material & Supplies Other Operatinq Expenses Taxes Other Than Income Taxes Technoloqy Expenses L T5 Dormancy With Drv Storage Total Payroll, Compensation & Labor Ohs Contractors & Professional Sen.ices Employee Related Expenses Insurance Licenses, Permits & Fees Material & Supplies Other Operating Expenses Plant Site & Transportation Expenses Taxes Other Than Income Taxes TechnoloQY Expenses UcensetTirmiifatiorLTotal <,

p,,,,,): ;:h, : \\ii.

'\\

i:7., *

"j

,:~c.

Dry Storage During Completion of SAFSTOR Preparations (SF4)

Payroll, Compensation & Labor Ohs Contractors & Professional Sen.ices Employee Related Expenses Licenses, Permits & Fees Material & Supplies Other Operatinq Expenses Technoloqv Expenses Drv Storage During Dormancy (SF5)

Payroll, Compensation & Labor Ohs Contractors & Professional Sen.ices Employee Related Expenses Insurance Licenses, Permits & Fees Material & Supplies Other OperatinQ Expenses Plant Site & Transportation Expenses Technoloqy Expenses

>' :(::

spent Fuerto1:ai

,'- ' 7,

',-C*

TotaJDe,c;;onimis~.ioning Expense.

2023 Actua Is_

110 390 (79)

(107) 40 (143) 3 (3'

9 3,691 1,821 223 5

460 468 28 457 (3) 172 58

',.*~* :~;801,:

1,268 183 988 6

1 9

5 77 6,313 4,617 1,006 2

(2' 490 27 130 15 28 7,581' k

11,~82 4Attachment D total decommissioning expense excludes Iowa sales tax refund and other immaterial reclass adjustments for previous completed periods.

Duane Arnold Energy Center 2024 ISFSI Decommissioning Financial Assurance Update 10 CFR 72.30( c)

The detailed site-specific ISFSI decommissioning cost estimate is $2,234,000 (for period of2024-2080, in 2023 dollars). The following table summarizes Attachments C-1, C-2 and, C-3 which reflects the trust balance as of 12/31/23 and the projected fund balance remaining after decommissioning and the ISFSI decommissioning cost estimate.

Projected Trust Fund ISFSI Decommissioning Trust Balance as of 12/31/23 Balance After Licensee (2023$ Thousands)

Decommissioning Cost Estimate (2023$ Thousands)

(2023$ Thousands)

Duane Arnold -

480,722 1,564 NextEra 446,764 Duane Arnold -

83,636 CIPCO 72,583 447 Duane Arnold -

42,368 Corn Belt 37,529 223 The following table supplements the ISFSI decommissioning funding plan to address new information that may affect the previously submitted reports in accordance with 10 CFR 72.30(c)(l-4).

Spills of radioactive material producing additional residual None radioactivity in onsite subsurface material Facility modifications None Changes in authorized possession limits None Actual remediation costs that exceed previous cost estimate None