NL-23-0208, Independent Spent Fuel Storage Installation ISFSI, Decommissioning Funding Plan Triennial Update

Independent Spent Fuel Storage Installation ISFSI, Decommissioning Funding Plan Triennial Update

ML23088A173
Person / Time
Site:	Hatch, Vogtle, Farley, 07200042, 07200036, 07201039
Issue date:	03/29/2023
From:	Brown R Southern Nuclear Operating Co
To:	Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation, Document Control Desk
References
NL-23-0208
Download: ML23088A173 (1)

Text

SNC Regulatory Affairs 3535 Colonnade Parkway Birmingham, AL 35243 205.992.5000 tel 205.992.7795 fax March 29, 2023 NL-23-0208 Docket Nos.: 72-36 72-42 72-1039 ATTN: Document Control Desk Director, Division of Spent Fuel Management Office of Nuclear Material Safety and Safeguards U. S. Nuclear Regulatory Commission Washington, D. C. 20555-0001 Joseph M. Farley Nuclear Plant - Units 1 and 2 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Vogtle Electric Generating Plant - Units 1 and 2 Independent Spent Fuel Storage Installation ISFSI Decommissioning Funding Plan Triennial Update Ladies and Gentlemen:

In accordance with 10 CFR 72.30(c), Southern Nuclear Operating Company (SNC) hereby submits the enclosed Independent Spent Fuel Storage Installation (ISFSI) decommissioning funding plans for Joseph M. Farley Nuclear Plant (Farley) Units 1 and 2 (Docket 72-42), Edwin I.

Hatch Nuclear Plant (Hatch) Units 1 and 2 (Docket 72-36), and Vogtle Electric Generating Plant (Vogtle) Units 1 and 2 (Docket 72-1039).

This letter contains no NRC commitments. If you have any questions or if additional information is needed, please contact Ryan Joyce at 205.992.6468.

Respectfully submitted, R. Keith Brown Regulatory Affairs Director efb/cbg

Enclosures:

1. Farley ISFSI Decommissioning Funding Plan Triennial Update

2. Hatch ISFSI Decommissioning Funding Plan Triennial Update

3. Vogtle ISFSI Decommissioning Funding Plan Triennial Update

U. S. Nuclear Regulatory Commission NL-23-0208 Page 2 cc: NRC Director - Division of Spent Fuel Management NRC Region II Regional Administrator NRC NRR Project Manager - Farley, Hatch, and Vogtle NRC Senior Resident Inspector - Farley, Hatch, and Vogtle Alabama Power Company Georgia Power Company Oglethorpe Power Corporation Municipal Electric Authority of Georgia Dalton Utilities SNC Document Control R-Type: PP1.006

Joseph M. Farley Nuclear Plant - Units 1 and 2 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Vogtle Electric Generating Plant - Units 1 and 2 Independent Spent Fuel Storage Installation ISFSI Decommissioning Funding Plan Triennial Update Enclosure 1 Farley ISFSI Decommissioning Funding Plan Triennial Update to NL-23-0208 Farley ISFSI Decommissioning Funding Plan Triennial Update Joseph M. Farley Nuclear Plant - Units 1 and 2 ISFSI Decommissioning Funding Plan Triennial Update Background and Introduction The Nuclear Regulatory Commission (NRC) issued its final rule on Decommissioning Planning on June 17, 2011, with the rule becoming effective on December 17, 2012. Subpart 72.30, Financial assurance and recordkeeping for decommissioning, requires that Southern Nuclear Operating Company (SNC) submit for NRC review and approval a decommissioning funding plan that demonstrates reasonable assurance that funds will be available to decommission the Independent Spent Fuel Storage Installation (ISFSI). In accordance with Subpart 72.30(b) and (c) of the rule, this enclosure provides the required triennial update, including a detailed cost estimate, with adjustments as necessary to account for changes in costs and site conditions.

Spent Fuel and ISFSI Management Strategy The operating licenses for the Farley Nuclear Plant (Farley) Units 1 & 2 are currently set to expire on June 25, 2037 and March 31, 2041 respectively. Approximately 5,520 spent fuel assemblies are currently projected to be generated as a result of plant operations through the license expiration date. The Farley ISFSI is operated in accordance with the general license provisions of 10 CFR 72.210.

The spent fuel pools are assumed to contain approximately 1,340 spent fuel assemblies after the final core offloads. To facilitate immediate dismantling or safe-storage operations, the spent fuel that cannot be transferred directly to the DOE from the pool is assumed to be packaged in dry storage casks for interim storage at the ISFSI. Transferring the spent fuel from the pool to the ISFSI will permit decontamination and dismantling of the spent fuel pool systems and allow termination of the Part 50 license using the DECON method described in NUREG-0586, Final Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities, Supp. 1.

Completion of the ISFSI decommissioning process is dependent upon the DOEs ability to remove spent fuel from the site. DOEs repository program assumes that spent fuel allocations will be accepted for disposal from the nations commercial nuclear plants, with limited exceptions, in the order (the queue) in which it was discharged from the reactor. The SNC spent fuel management plan for Farley assumes: 1) a 2032 start date for DOE initiating transfer of commercial spent fuel to a federal facility, and 2) completion of spent fuel receipt by year 2075. The completion date is based on DOEs allocation/receipt schedules with the oldest fuel receiving the highest priority.

The end date assumes a maximum rate of transfer of 3,000 metric tons of uranium/year.

At the conclusion of the spent fuel transfer process, the ISFSI will be promptly decommissioned by removing and disposing of residual radioactivity and verifying that remaining materials satisfy NRC release criteria.

ISFSI Description The Farley ISFSI uses a Holtec International (Holtec) HI-STORM 100 dry storage system. The HI-STORM 100 is comprised of a multi-purpose canister (MPC) and storage overpack. The MPCs are assumed to be transferred directly to the DOE and not returned to the station. Some of the E1 - 1 to NL-23-0208 Farley ISFSI Decommissioning Funding Plan Triennial Update remaining overpacks are assumed to have residual radioactivity due to neutron-induced activation resulting from long-term storage of the spent fuel.

SNCs current spent fuel management plan for Farley spent fuel would result in 123 spent fuel storage casks (32 assemblies per cask) being placed on a storage pad at the site after all spent fuel has been removed from the spent fuel pool. This represents approximately 71% of the total spent fuel projected to be generated during the currently licensed operating period. The balance of the fuel assemblies is assumed to have been transferred directly to the DOE from the Farley spent fuel pools.

In addition to the spent fuel casks located on the ISFSI pad after shutdown there are projected to be additional casks used for Greater-than-Class-C (GTCC) storage. The storage overpacks used for the GTCC canisters (estimated quantity of 8) 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.

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

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 size of the ISFSI pad is sufficient to store the projected amount of spent fuel and is assumed to be 44,935 square feet in surface area.

Some of the inner steel-liners of the HI-STORM concrete overpacks, 10 of the 123 total, are assumed to contain low levels of neutron-induced residual radioactivity that would necessitate remediation at the time of decommissioning. The estimate is based upon the number of casks required for the final core off-load (i.e., 157 offloaded assemblies, 32 assemblies per cask) which results in 5 overpacks per unit. It is assumed that these are the final overpacks to be emptied of their spent fuel casks because the DOE plans to dispose of the oldest fuel first. These final 10 overpacks are assumed to be disposed of before sufficient time has elapsed for radioactive decay of the neutron activation products.

This analysis assumes that good radiological practices are employed, and there will be no residual contamination left on the concrete ISFSI pad or other facilities at the Farley ISFSI. Consequently, only verification surveys are assumed in the decommissioning estimate.

There is no expected subsurface material in the proximity of the ISFSI containing 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. The estimate includes labor and overhead for SNC oversight of the contractor, SNC security, and other site operating costs.

Low-level radioactive waste disposal costs are based on SNCs current cost of disposal at the EnergySolutions Clive, Utah disposal site.

E1 - 2 to NL-23-0208 Farley ISFSI Decommissioning Funding Plan Triennial Update Costs are reported in 2022 dollars. Consistent with NUREG-1757, a 25% contingency has been added. The estimate is limited to costs necessary to terminate the ISFSI license and meet the

§20.1402 criteria for unrestricted use. Disposition of released material and structures is outside the scope of the estimate.

In accordance with 10 CFR 72.30(c)(1)-(4), the following 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 Farley ISFSI.

(2) Facility modifications: There have been two additional spent fuel storage pads added to the ISFSI since the previous report. They have been accounted for in this decommissioning cost estimate.

(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, no actual remediation costs exceed the previous cost estimate.

All expenditures are conservatively assumed to be incurred in the year 2076, the year following all spent fuel removal.

Cost Estimate and Financial Assurance Certification The estimated cost to decommission the Farley ISFSI and release the facility for unrestricted use is provided in Table 2. The estimate for ISFSI decommissioning is $12,607,000 (2022$) shared by both operating units.

As shown in Table 3, adequate funds for decommissioning of the Farley ISFSI are assured by the same external sinking fund method used for the nuclear decommissioning trust (NDT) fund established for each unit in accordance with 10 CFR 50.75. The Farley NDTs are maintained and adjusted as necessary to ensure that the total amount of funds is sufficient to pay the ISFSI decommissioning costs. Funds in excess of the amount required for decommissioning the Part 50 facility provide adequate assurance that funding for decommissioning the ISFSI will be available upon expiration of the Part 50 operating licenses.

E1 - 3 to NL-23-0208 Farley ISFSI Decommissioning Funding Plan Triennial Update Table 1 Significant Quantities and Physical Dimensions Item Area (ft2) Notes ISFSI Pad 44,935 No residual radioactivity ISFSI Overpack (HI-STORM 100)

Item Value Notes Overall Height (inches) 218.0 Outside Diameter (inches) 132.0 Inside Diameter (inches) 73.5 Inner Liner Thickness (inches) 1.25 Quantity (total) 131 Spent Fuel 123 + GTCC 8 Quantity (with residual radioactivity) 10 The number of overpacks used to store the last complete core offloads Total Surface Area of Overpack Inner Liner with Residual 3,167 Radioactivity (square feet)

Low-Level Radioactive Waste (cubic feet) 51,369 Low-Level Radioactive Waste (packaged density- lbs./cu.ft.) 55 Other Potentially Impacted Items Item Value Notes Number of Overpacks used for GTCC storage 8 No residual radioactivity Transfer Cask 1 No residual radioactivity E1 - 4

Enclosure 1 to NL-23-0208 Farley ISFSI Decommissioning Funding Plan Triennial Update Table 2 ISFSI Decommissioning Costs and Waste Volumes Waste (thousands, 2022 dollars) Volume Person-Hours Removal Packaging Transport Disposal Other Total (ft3) Contractor Licensee NRC Decommissioning Contractor Planning (characterization, specs and procedures) - - - - 451 451 - 1,216 Remediation (activated liner removal) 305 247 2,229 2,782 5,562 51,369 2,991 -

License Termination (radiological surveys) - - - - 2,548 2,548 - 16,706 -

Subtotal 305 247 2,229 2,782 2,999 8,561 51,369 20,914 -

Supporting Costs NRC and NRC Contractor Fees and Costs 541 541 1,153 Insurance 87 87 Property Tax 2 2 Plant Energy Budget 4 4 Site Overhead 25 25 Corporate Overheads 134 134 Security Staff Cost 337 337 4,958 Utility Staff Cost 395 395 3,761 Subtotal 1,524 1,524 8,719 Total (w/o contingency) 305 247 2,229 2,782 4,523 10,085 51,369 20,914 8,719 1,153 Total (with 25% contingency) 12,606 E1 - 5 to NL-23-0208 Farley ISFSI Decommissioning Funding Plan Triennial Update Table 3 - Financial Assurance - Alabama Power Company Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $551,654,000

$551,654,000 2 Total amount accumulated in the trust fund at the end of $569,506,402 $555,749,283 2022 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 4.5% 4.5%

(b) Rates of earnings on decommissioning funds 7.0% 7.0%

(c) Real rate of return 2.5% 2.5%

4 Projected ending fund balance (U1 - year 2037, U2 year $1,529,342,556 $1,924,720,205 2041) 5 Projected NRC minimum requirements (U1 - year 2037, U2 $1,067,606,301 $1,273,140,372

- year 2041) 6 Surplus funds available for decommissioning for U1 in 2037 and Unit 2 in 2041.

$461,736,255 $651,579,833 7 ISFSI decommissioning cost study estimate (2022$) $6,305,000 $6,301,000 8 Projected ISFSI decommissioning cost estimate (U1 - year $12,202,000 $14,542,000 2037, U2 - year 2041)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E1 - 6

Joseph M. Farley Nuclear Plant - Units 1 and 2 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Vogtle Electric Generating Plant - Units 1 and 2 Independent Spent Fuel Storage Installation ISFSI Decommissioning Funding Plan Triennial Update Enclosure 2 Hatch ISFSI Decommissioning Funding Plan Triennial Update to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Edwin I. Hatch Nuclear Plant - Units 1 and 2 ISFSI Decommissioning Funding Plan Triennial Update Background and Introduction The Nuclear Regulatory Commission (NRC) issued its final rule on Decommissioning Planning on June 17, 2011, with the rule becoming effective on December 17, 2012. Subpart 72.30, Financial assurance and recordkeeping for decommissioning, requires that Southern Nuclear Operating Company (SNC) submit for NRC review and approval a decommissioning funding plan that demonstrates reasonable assurance that funds will be available to decommission the Independent Spent Fuel Storage Installation (ISFSI). In accordance with Subpart 72.30(b) and (c) of the rule, this enclosure provides the required triennial update, including a detailed cost estimate, with adjustments as necessary to account for changes in costs and site conditions.

Spent Fuel and ISFSI Management Strategy The operating licenses for the Hatch Nuclear Plant (Hatch) Units 1 & 2 are currently set to expire on August 6, 2034 and June 13, 2038 respectively. Approximately 14,823 spent fuel assemblies are currently projected to be generated as a result of plant operations through the license expiration date. The Hatch ISFSI is operated in accordance with the general license provisions of 10 CFR 72.210.

The spent fuel pools are assumed to contain approximately 4,156 spent fuel assemblies after the final core offloads. To facilitate immediate dismantling or safe-storage operations, the spent fuel that cannot be transferred directly to the DOE from the pool is assumed to be packaged in dry storage casks for interim storage at the ISFSI. Transferring the spent fuel from the pool to the ISFSI will permit decontamination and dismantling of the spent fuel pool systems and allow termination of the Part 50 license using the DECON method described in NUREG-0586, Final Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities, Supp. 1.

Completion of the ISFSI decommissioning process is dependent upon the DOEs ability to remove spent fuel from the site. DOEs repository program assumes that spent fuel allocations will be accepted for disposal from the nations commercial nuclear plants, with limited exceptions, in the order in which it was discharged from the reactor. The SNC spent fuel management plan for Hatch assumes: 1) a 2032 start date for DOE initiating transfer of commercial spent fuel to a federal facility, and 2) completion of spent fuel receipt by year 2074. The completion date is based on DOEs allocation/receipt schedules with the oldest fuel receiving the highest priority. The end date assumes a maximum rate of transfer of 3,000 metric tons of uranium/year.

At the conclusion of the spent fuel transfer process, the ISFSI will be promptly decommissioned by removing and disposing of residual radioactivity and verifying that remaining materials satisfy NRC release criteria.

ISFSI Description The Hatch ISFSI uses a Holtec International (Holtec) HI-STORM 100 dry storage system. The HI-STORM 100 is comprised of a multi-purpose canister (MPC) and storage overpack. The MPCs E2 - 1 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update are assumed to be transferred directly to the DOE and not returned to the station. Some of the remaining overpacks are assumed to have residual radioactivity due to neutron-induced activation resulting from long-term storage of the spent fuel.

SNCs current spent fuel management plan for Hatch spent fuel would result in 138 spent fuel storage casks (68 assemblies per cask) and 39 spent fuel storage casks (52 assemblies per cask) being placed on a storage pad at the site after all spent fuel has been removed from the spent fuel pool. This represents approximately 77% of the total spent fuel projected to be generated during the currently licensed operating period. The balance of the fuel assemblies is assumed to have been transferred directly to the DOE from the Hatch spent fuel pools.

In addition to the spent fuel casks located on the ISFSI pad after shutdown there are projected to be additional casks used for Greater-than-Class-C (GTCC) storage. The storage overpacks used for the GTCC canisters (estimated quantity of 6) 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.

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

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 size of the ISFSI pad is sufficient to store the projected amount of spent fuel and is assumed to be 48,500 square feet in surface area.

Some of the inner steel-liners of the HI-STORM concrete overpacks, 22 of the 177 total, are assumed to contain low levels of neutron-induced residual radioactivity that would necessitate remediation at the time of decommissioning. The estimate is based upon the number of casks required for the final core off-load (i.e., 560 offloaded assemblies, 52 assemblies per cask) which results in 11 overpacks per unit. It is assumed that these are the final overpacks to be emptied of their spent fuel casks because the DOE plans to dispose of the oldest fuel first. These final 22 overpacks are assumed to be disposed of before sufficient time has elapsed for radioactive decay of the neutron activation products.

This analysis assumes that good radiological practices are employed, and there will be no residual contamination left on the concrete ISFSI pad or other facilities at the Hatch ISFSI. Consequently, only verification surveys are assumed in the decommissioning estimate.

There is no expected subsurface material in the proximity of the ISFSI containing 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. The estimate includes labor and overhead for SNC oversight of the contractor, SNC security, and other site operating costs.

Low-level radioactive waste disposal costs are based on SNCs current cost of disposal at the EnergySolutions Clive, Utah disposal site.

E2 - 2 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Costs are reported in 2022 dollars. Consistent with NUREG-1757, a 25% contingency has been added. The estimate is limited to costs necessary to terminate the ISFSI license and meet the

§20.1402 criteria for unrestricted use. Disposition of released material and structures is outside the scope of the estimate.

In accordance with 10 CFR 72.30(c)(1)-(4), the following 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 Hatch ISFSI.

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

(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, no actual remediation costs exceed the previous cost estimate.

All expenditures are conservatively assumed to be incurred in the year 2075, the year following all spent fuel removal.

Cost Estimate and Financial Assurance Certification The estimated cost to decommission the Hatch ISFSI and release the facility for unrestricted use is provided in Table 2. The estimate for ISFSI decommissioning is $20,453,000 (2022$) shared by both operating units.

As shown in Table 3, adequate funds for decommissioning of the Hatch ISFSI are assured by the same external sinking fund method used for the nuclear decommissioning trust (NDT) fund established for each unit in accordance with 10 CFR 50.75. The Hatch NDTs are maintained and adjusted as necessary to ensure that the total amount of funds is sufficient to pay the ISFSI decommissioning costs. Funds in excess of the amount required for decommissioning the Part 50 facility provide adequate assurance that funding for decommissioning the ISFSI will be available upon expiration of the Part 50 operating licenses.

E2 - 3 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Table 1 Significant Quantities and Physical Dimensions Item Area (ft2) Notes ISFSI Pad 47,816 No residual radioactivity ISFSI Overpack (HI-STORM 100)

Item Value Notes (all dimensions are nominal)

Overall Height (inches) 229.0 Outside Diameter (inches) 132.0 Inside Diameter (inches) 73.5 Inner Liner Thickness (inches) 1.25 Quantity (total) 183 Spent Fuel 177 + GTCC 6 Quantity (with residual radioactivity) 22 The number of overpacks used to store the last complete core offloads Total Surface Area of Overpack Inner Liner with Residual 7,368 Radioactivity (square feet)

Low-Level Radioactive Waste (cubic feet) 112,085 Low-Level Radioactive Waste (packaged density- lbs./cu.ft.) 54 Other Potentially Impacted Items Item Value Notes Number of Overpacks used for GTCC storage 6 No residual radioactivity Transfer Cask 1 No residual radioactivity E2 - 4

Enclosure 2 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Table 2 ISFSI Decommissioning Costs and Waste Volumes Waste (thousands, 2022 dollars) Volume Person-Hours NRC/ NRC Removal Packaging Transport Disposal Other Total (ft3) Contractor Licensee Contractor Decommissioning Contractor Planning (characterization, 522 522 1,288 specs and procedures)

Remediation 641 581 4,052 6,616 11,891 112,085 6,710 (activated liner removal)

License Termination 2,043 2,043 16,522 (radiological surveys) 641 581 4,052 6,616 3,079 14,970 112,085 23,363 1,288 Subtotal Supporting Costs NRC and NRC Contractor 585 585 1,153 Fees and Costs Insurance 92 92 Property Tax 0 0 Plant Energy Budget 4 4 Security (Industrial) 277 277 4,999 Hatch Oversight Staff 434 434 3,792 Subtotal 0 0 0 0 1,392 1,392 0 0 8,792 1,153 641 581 4,052 6,616 4,472 16,362 112,085 23,363 10,080 1,153 Total (w/o contingency) 20,453 Total (with 25% contingency)

E2 - 5 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Table 3 - Financial Assurance - Georgia Power Company (50.1% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $338,857,303 $338,857,303 2 Total amount accumulated in the trust fund at the end of 2022 $320,848,000 $304,261,000 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.78% 2.77%

(b) Rates of earnings on decommissioning funds 4.78% 4.77%

2.00% 2.00%

(c) Real rate of return 4 Projected fund balance (U1 - year 2034, U2 year 2038) $569,014,000 $641,881,000 5 Projected NRC minimum requirements (U1 - year 2034, U2 - year $470,891,000 $524,661,000 2038) 6 Surplus funds available for decommissioning for U1 in 2034 and Unit 2 in 2038.

$98,124,000 $117,220,000 7 ISFSI decommissioning cost study estimate (2022$) $5,123,477 $5,123,476 8 Projected ISFSI decommissioning cost estimate (U1 - year 2034, U2 $7,111,498 $7,932,798

- year 2038)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E2 - 6 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Table 4 - Financial Assurance - Oglethorpe Power Corporation (30% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $202,908,584 $202,908,584 2 Total amount accumulated in the trust fund at the end of 2022 $186,156,225 $146,351,765 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.776% 2.771%

(b) Rates of earnings on decommissioning funds 4.776% 4.771%

2.00% 2.00%

(c) Real rate of return 4 Projected ending fund balance (U1 - year 2034, U2 year 2038) $325,851,209 $308,500,158 5 Projected NRC minimum requirements (U1 - year 2034, U2 - year $281,839,490 $314,217,688 2038) 6 Deficit/Surplus funds projected to be accumulated at license $44,011,719 <5,717,530>

termination.

7 Surplus funds available for decommissioning the Hatch station $38,294,189 8 ISFSI decommissioning cost study estimate (2022$) $6,135,900 9 Projected ISFSI decommissioning cost estimate (U1 - year 2034, U2 $8,490,539

- year 2038)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E2 - 7 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Table 5 - Financial Assurance - Municipal Electric Authority of Georgia (17.7% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $119,716,053

$119,716,053 2 Total amount accumulated in the trust fund at the end of 2022 $143,314,311 $142,792,198 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.50% 2.50%

(b) Rates of earnings on decommissioning funds 4.22% 4.22%

(c) Real rate of return 1.72% 1.72%

4 Projected ending fund balance (U1 - year 2034, U2 year 2038) $246,037,000 $276,096,000 5 Projected NRC minimum requirements (U1 - year 2034, U2 - year $161,004,782 $177,719,154 2038) 6 Surplus funds available for decommissioning for U1 in 2034 and Unit 2 in 2038.

$85,032,218 $98,376,846 7 ISFSI decommissioning cost study estimate (2022$) $1,810,091 $1,810,090 8 Projected ISFSI decommissioning cost estimate (U1 - year 2034, U2 $2,434,371 $2,687,089

- year 2038)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E2 - 8 to NL-23-0208 Hatch ISFSI Decommissioning Funding Plan Triennial Update Table 6 - Financial Assurance - Dalton Utilities (2.2% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $14,879,961

$14,879,961 2 Total amount accumulated in the trust fund at the end of 2022. $12,796,824 $13,212,283 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.78% 2.77%

(b) Rates of earnings on decommissioning funds 5.00% 5.00%

(c) Real rate of return 2.22% 2.23%

4 Projected ending fund balance (U1 - year 2035, U2 year 2039) $25,455,833 $31,893,965 5 Projected NRC minimum requirements (U1 - year 2034, U2 - year $20,677,839 $23,038,993 2038) 6 Surplus funds available for decommissioning the ISFSI U1 in 2035 and Unit 2 in 2039.

$4,777,994 $8,854,972 7 ISFSI decommissioning cost study estimate (2022$) $224,983 $224,983 8 Projected ISFSI decommissioning cost estimate (U1 - year 2034, U2 $312,646 $348,346

- year 2038)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E2 - 9

Joseph M. Farley Nuclear Plant - Units 1 and 2 Edwin I. Hatch Nuclear Plant - Units 1 and 2 Vogtle Electric Generating Plant - Units 1 and 2 Independent Spent Fuel Storage Installation ISFSI Decommissioning Funding Plan Triennial Update Enclosure 3 Vogtle ISFSI Decommissioning Funding Plan Triennial Update to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Vogtle Electric Generating Plant - Units 1 and 2 ISFSI Decommissioning Funding Plan Triennial Update Background and Introduction The Nuclear Regulatory Commission (NRC) issued its final rule on Decommissioning Planning on June 17, 2011, with the rule becoming effective on December 17, 2012. Subpart 72.30, Financial assurance and recordkeeping for decommissioning, requires that Southern Nuclear Operating Company (SNC) submit for NRC review and approval a decommissioning funding plan that demonstrates reasonable assurance that funds will be available to decommission the Independent Spent Fuel Storage Installation (ISFSI). In accordance with Subpart 72.30(b) and (c) of the rule, this enclosure provides the required triennial update, including a detailed cost estimate, with adjustments as necessary to account for changes in costs and site conditions.

Spent Fuel and ISFSI Management Strategy The operating licenses for the Vogtle Electric Generating Plant (Vogtle) Units 1 & 2 are currently set to expire on January 16, 2047 and February 9, 2049 respectively. Approximately 7,156 spent fuel assemblies are currently projected to be generated as a result of plant operations through the license expiration date. The Vogtle ISFSI is operated in accordance with the general license provisions of 10 CFR 72.210.

The spent fuel pools are assumed to contain a total of approximately 2,409 spent fuel assemblies after the final core offloads. To facilitate immediate dismantling or safe-storage operations, the spent fuel that cannot be transferred directly to the DOE from the pool is assumed to be packaged in dry storage casks for interim storage at the ISFSI. Transferring the spent fuel from the pool to the ISFSI will permit decontamination and dismantling of the spent fuel pool systems and allow termination of the Part 50 license using the DECON method described in NUREG-0586, Final Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities, Supp. 1.

Completion of the ISFSI decommissioning process is dependent upon the DOEs ability to remove spent fuel from the site. DOEs repository program assumes that spent fuel allocations will be accepted for disposal from the nations commercial nuclear plants, with limited exceptions, in the order (the queue) in which it was discharged from the reactor. The SNC spent fuel management plan for Vogtle assumes: 1) a 2032 start date for DOE initiating transfer of commercial spent fuel to a federal facility, and 2) completion of spent fuel receipt by year 2078. The completion date is based on DOEs allocation/receipt schedules with the oldest fuel receiving the highest priority.

The end date assumes a maximum rate of transfer of 3,000 metric tons of uranium/year.

At the conclusion of the spent fuel transfer process, the ISFSI will be promptly decommissioned by removing and disposing of residual radioactivity and verifying that remaining materials satisfy NRC release criteria.

ISFSI Description The Vogtle ISFSI uses a Holtec International (Holtec) HI-STORM 100 dry storage system. The HI-STORM 100 is comprised of a multi-purpose canister (MPC) and storage overpack. The MPCs are assumed to be transferred directly to the DOE and not returned to the station. Some of the E3 - 1 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update remaining overpacks are assumed to have residual radioactivity due to neutron-induced activation resulting from long-term storage of the spent fuel.

SNCs current spent fuel management plan for Vogtle spent fuel would result in 93 spent fuel storage casks (32 assemblies per cask) and 78 spent fuel storage casks (24 assemblies per cask) being placed on a storage pad at the site after all spent fuel has been removed from the spent fuel pool. This represents approximately 67% of the total spent fuel projected to be generated during the currently licensed operating period. The balance of the fuel assemblies is assumed to have been transferred directly to the DOE from the Vogtle spent fuel pools.

In addition to the spent fuel casks located on the ISFSI pad after shutdown there are projected to be additional casks used for Greater-than-Class-C (GTCC) storage. The storage overpacks used for the GTCC canisters (estimated quantity of 10) 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.

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

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 size of the ISFSI pad is sufficient to store the projected amount of spent fuel and is assumed to be 53,309 square feet in surface area.

Some of the inner steel-liners of the HI-STORM concrete overpacks, 18 of the 171 total, are assumed to contain low levels of neutron-induced residual radioactivity that would necessitate remediation at the time of decommissioning. The estimate is based upon the number of casks required for the final core off-load (i.e., 193 offloaded assemblies, 24 assemblies per cask) which results in 9 overpacks per unit. It is assumed that these are the final overpacks to be emptied of their spent fuel casks because the DOE plans to dispose of the oldest fuel first. These final 18 overpacks are assumed to be disposed of before sufficient time has elapsed for radioactive decay of the neutron activation products.

This analysis assumes that good radiological practices are employed, and there will be no residual contamination left on the concrete ISFSI pad or other facilities at the Vogtle ISFSI. Consequently, only verification surveys are assumed in the decommissioning estimate.

There is no expected subsurface material in the proximity of the ISFSI containing 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. The estimate includes labor and overhead for SNC oversight of the contractor, SNC security, and other site operating costs.

Low-level radioactive waste disposal costs are based on SNCs current cost of disposal at the EnergySolutions Clive, Utah disposal site.

E3 - 2 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Costs are reported in 2022 dollars. Consistent with NUREG-1757, a 25% contingency has been added. The estimate is limited to costs necessary to terminate the ISFSI license and meet the

§20.1402 criteria for unrestricted use. Disposition of released material and structures is outside the scope of the estimate.

In accordance with 10 CFR 72.30(c)(1)-(4), the following 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 Vogtle ISFSI.

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

(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, no actual remediation costs exceed the previous cost estimate.

All expenditures are conservatively assumed to be incurred in the year 2079, the year following all spent fuel removal.

Cost Estimate and Financial Assurance Certification The estimated cost to decommission the Vogtle ISFSI and release the facility for unrestricted use is provided in Table 2. The estimate for ISFSI decommissioning is $17,827,000 (2022$) shared by both operating units.

As shown in Table 3, adequate funds for decommissioning of the Vogtle ISFSI are assured by the same external sinking fund method used for the nuclear decommissioning trust (NDT) fund established for each unit in accordance with 10 CFR 50.75. The Vogtle NDTs are maintained and adjusted as necessary to ensure that the total amount of funds is sufficient to pay the ISFSI decommissioning costs. Funds in excess of the amount required for decommissioning the Part 50 facility provide adequate assurance that funding for decommissioning the ISFSI will be available upon expiration of the Part 50 operating licenses.

E3 - 3 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Table 1 Significant Quantities and Physical Dimensions Item Area (ft2) Notes ISFSI Pad 53,309 No residual radioactivity ISFSI Overpack (HI-STORM 100)

Item Value Notes Overall Height (inches) 218 Outside Diameter (inches) 132 Inside Diameter (inches) 73.5 Inner Liner Thickness (inches) 1.25 Quantity (total) 181 Spent Fuel 171 + GTCC 10 Quantity (with residual radioactivity) 18 The number of overpacks used to store the last complete core offloads Total Surface Area of Overpack Inner Liner 5,700 with Residual Radioactivity (square feet)

Low-Level Radioactive Waste (cubic feet) 91,270 Low-Level Radioactive Waste (packaged 54 density- lbs./cu.ft.)

Other Potentially Impacted Items Item Value Notes Number of Overpacks used for GTCC storage 10 No residual radioactivity Transfer Cask 1 No residual radioactivity E3 - 4

Enclosure 3 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Table 2 ISFSI Decommissioning Costs and Waste Volumes Waste (thousands, 2022 dollars) Volume Person-Hours NRC/ NRC Removal Packaging Transport Disposal Other Total (ft3) Contractor Licensee Contractor Decommissioning Contractor Planning (characterization, specs and procedures) 544 544 1,312 Remediation (activated liner removal) 527 427 3,267 5,367 9,587 91,270 5,359 License Termination (radiological surveys) 2,778 2,778 18,468 Subtotal 527 427 3,267 5,367 3,322 12,909 91,270 23,827 1,312 Supporting Costs NRC and NRC Contractor Fees and Costs 588 588 1,153 Insurance 92 92 Property Tax 0 0 Plant Energy Budget 5 5 Security Staff Cost 234 234 5,040 Vogtle Oversight Staff 434 434 3,824 Subtotal 1,353 1,353 8,864 1,153 Total (w/o contingency) 527 427 3,267 5,367 4,675 14,262 91,270 23,827 10,176 1,153 Total (with 25% contingency) 17,827 E3 - 5 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Table 3 - Financial Assurance - Georgia Power Company (45.7% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $265,175,556

$265,175,556 2 Total amount accumulated in the trust fund at the end of 2022 $175,273,000 $204,955,000 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.70% 2.70%

(b) Rates of earnings on decommissioning funds 4.70% 4.70%

(c) Real rate of return 2.00% 2.00%

4 Projected ending fund balance (U1 - year 2047, U2 year 2049) $592,805,000 $701,823,000 5 Projected NRC minimum requirements (U1 - year 2047, U2 - year $516,172,161 $544,421,748 2049) 6 Surplus funds available for decommissioning for U1 in 2047 and Unit 2 in 2049.

$76,632,839 $157,401,252 7 ISFSI decommissioning cost study estimate (2022$) $4,073,470 $4,073,469 8 Projected ISFSI decommissioning cost estimate (U1 - year 2047, U2 $7,929,131 $8,363,083

- year 2049)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E3 - 6 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Table 4 - Financial Assurance - Oglethorpe Power Corporation (30% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $174,075,857

$174,075,857 2 Total amount accumulated in the trust fund at the end of 2022 $108,602,652 $98,375,539 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.697% 2.703%

(b) Rates of earnings on decommissioning funds (c) Real rate of return 4.697% 4.703%

2.00% 2.00%

4 Projected ending fund balance (U1 - year 2047, U2 year 2049) $342,134,106 $340,238,544 5 Projected NRC minimum requirements (U1 - year 2047, U2 - year $338,596,782 $357,670,730 2049) 6 Deficit/Surplus funds projected to be accumulated at license $3,537,324 <$17,432,186>

termination.

7 Deficit of funds for decommissioning the Vogtle 1-2 station ISFSI <13,894,862> as of 12/31/2022 Surplus of funds for decommissioning the Vogtle 1-2 station ISFSI 0F 1 24,214,871 as of 2/28/2023 8 ISFSI decommissioning cost study estimate (2022$) 5,348,100 9 Projected ISFSI decommissioning cost estimate (U1 - year 2047, U2 9,976,352

- year 2049)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy 1

As demonstrated in the 2022 biennial 10 CFR 50.75 financial assurance report. (SNC Letter # NL-23-0014)

E3 - 7 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Table 5 - Financial Assurance - Municipal Electric Authority of Georgia (22.7% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $131,718,000

$131,718,000 2 Total amount accumulated in the trust fund at the end of 2022 $143,295,406 $137,929,286 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.50% 2.50%

(b) Rates of earnings on decommissioning funds 4.22% 4.22%

(c) Real rate of return 1.72% 1.72%

4 Projected ending fund balance (U1 - year 2047, U2 year 2049) $401,496,000 $444,574,000 5 Projected NRC minimum requirements (U1 - year 2047, U2 - year $244,198,000 $256,561,000 2049) 6 Surplus funds available for decommissioning for U1 in 2047 and Unit 2 in 2049.

$157,298,000 $188,013,000 7 ISFSI decommissioning cost study estimate (2022$) $2,023,365 $2,023,364 8 Projected ISFSI decommissioning cost estimate (U1 - year 2047, U2 $3,751,206 $3,941,108

- year 2049)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

E3 - 8 to NL-23-0208 Vogtle ISFSI Decommissioning Funding Plan Triennial Update Table 6 - Financial Assurance - Dalton Utilities (1.6% Ownership)

Unit 1 Unit 2 1 The NRC minimum decommissioning estimate $9,284,046 $9,284,046 2 Total amount accumulated in the trust fund at the end of 2022 $7,414,151 $6,391,238 3 Assumptions regarding:

(a) Rates of escalation in decommissioning costs 2.70% 2.70%

(b) Rates of earnings on decommissioning funds (c) Real rate of return 5.00% 5.00%

2.30% 2.30%

4 Projected ending fund balance (U1 - year 2047, U2 year 2049) $28,218,693 $28,791,302 5 Projected NRC minimum requirements pursuant to 10 CFR 50.75 (b) $18,071,674 $19,060,718 and (c) (U1 - year 2047, U2 - year 2049) 6 Surplus funds available for decommissioning for U1 in 2047 and Unit 2 in 2049.

$10,147,019 $9,730,584 7 ISFSI decommissioning cost study estimate (2022$) $142,616 $142,616 8 Projected ISFSI decommissioning cost estimate (U1 - year 2047, U2 $277,606 $292,799

- year 2049)

• The NRC minimum amount is based on NUREG-1307, Rev. 19, for the burial factor, the Dec. 2022 BLS data for labor, and the Sept. 2022 BLS data for energy.

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