NOC-AE-18003592, ISFSI - Decommissioning Funding Plan for the Independent Spent Fuel Storage Installation

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ISFSI - Decommissioning Funding Plan for the Independent Spent Fuel Storage Installation
ML18269A258
Person / Time
Site: South Texas, 07201041  STP Nuclear Operating Company icon.png
Issue date: 09/26/2018
From: Marc-Anthony Murray
South Texas
To:
Document Control Desk, Office of Nuclear Material Safety and Safeguards, Office of Nuclear Reactor Regulation
References
NOC-AE-18003592, STI: 34707119
Download: ML18269A258 (18)
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Text

Nuclear Operating Company South Texas Project Electric Generating Station P.O. Box 289 Wadsworth, Texas 77433 September 26, 2018 NOC-AE-18003592 10CFR72.30(b)

U. S. Nuclear Regulatory Commission Attention: Document Control Desk Director, Division of Spent Fuel Management Office of Nuclear Materials Safety and Safeguards Washington, DC 20555-0001 South Texas Project Unit 1 and 2 ISFSI Docket Nos. 50-498, 50-499 and 72-1041 Decommissioning Fundinfl Plan for the Independent Spent Fuel Storage Installation In accordance with the provisions of 10 CFR 72.30(b), STP Nuclear Operating Company (STPNOC) is submitting the enclosed Decommissioning Funding Plan for the STPNOC Independent Spent Fuel Storage Installation (ISFSI). Enclosure 1 addresses each of the six criteria contained in 10 CFR 72.30(b), and references Enclosure 2, which provides details concerning the STPNOC ISFSI decommissioning cost estimates that were derived from TLG Services, Inc. estimates.

The information assembled is for the individual co-owners (owners) of the South Texas Project:

  • City Public Service Board of San Antonio; and
  • City of Austin - Austin Energy.

There are no commitments in this letter.

If there are any questions, please contact Rafael Gonzales at 361-972-4779.

Michael P. Murray Regulatory Affairs Manager rjg

Enclosures:

1) Decommissioning Funding Plan
2) Decommissioning Cost Estimate STI:34707119

NOC-AE-18003592 Page 2 of 2 ec:

(paper copy)

Regional Administrator, Region IV U.S. Nuclear Regulatory Commission 1600 East Lamar Boulevard Arlington, TX 76011-4511 Lisa M. Regner Senior Project Manager U.S. Nuclear Regulatory Commission One White Flint North (08H04)

H555RockvillePike Rockville, MD 20852 NRC Resident Inspector D. S. Nuclear Regulatory Commission P. 0. Box 289, Mail Code: MN116 Wadsworth.TX 77483

NOC-AE-18003592 Enclosure 1 Decommissioning Funding Plan

NOC-AE-18003592 Enclosure 1 Page 1 of 2 STP Decommissioning Funding Plan for STP Independent Spent Fuel Storage Installation (ISFSI)

The South Texas Project (STP) owners are providing the following information required by 10 CFR 72.30(b) to be included in the Decommissioning Funding Plan (DFP):

Requirement 1:

"(1) Information on how reasonable assurance will be provided that funds will be available to decommission the ISFSI or MRS."

Information for Requirement 1:

Pursuant to 10 CFR 72.30(e)(5), since STP Units 1 and 2 are power reactor licensees under 10 CFR 50, STP owners use the methods of 10 CFR 50.75(b), (e), and (h) to provide financial assurance associated with their respective ownership shares of the STP Units 1 and 2 ISFSI. The STP owners are using trust funds to ensure financial assurance.

Requirement 2:

"(2) A detailed cost estimate for decommissioning, in an amount reflecting:

(i) The cost of an independent contractor to perform all decommissioning activities; (ii) An adequate contingency factor; and (iii) The cost of meeting the § 20.1402 of this chapter criteria for unrestricted use, provided that, if the applicant or licensee can demonstrate its ability to meet the provisions of

§ 20.1403 of this chapter, the cost estimate may be based on meeting the § 20.1403 criteria."

Information for Requirement 2:

STP completed a decommissioning study in May 2018 for STP Units 1 and 2. This study included costs associated with the ISFSI decommissioning. Enclosure 2 includes information from that report specific to the ISFSI. Table G in Enclosure 2 provides a cost estimate for ISFSI decommissioning.

Requirement 3:

"(3) Identification of and justification for using the key assumptions contained in the DCE."

Information for Requirement 3: identifies and justifies the key assumptions used in the Decommissioning Cost Estimate forthelSFSI.

Requirement 4:

"(4) A description of the method of assuring funds for decommissioning from paragraph (e) of this section, including means for adjusting cost estimates and associated funding levels periodically over the life of the facility."

Information for Requirement 4:

The decommissioning cost estimate will be adjusted as necessary every three years, as required by 10 CFR 72.30(c). As indicated in the information for Requirement 1, STP owners use the methods of 10 CFR 50.75(b), (e), and (h) to provide financial assurance associated with its ownership share of the ISFSI. STP owners adjust their share of the amount of financial assurance required by 10 CFR 50.75(b) annually in accordance with paragraph (2) of that section, and further adjustment as required by 10 CFR 50.75(f)(3) and (5) at or about five years prior to the projected end of reactor operations.

NOC-AE-18003592 Enclosure 1 Page 2 of 2 Requirement 5:

"(5) The volume of onsite subsurface material containing residual radioactivity that will require remediation to meet the criteria for license termination."

Information for Requirement 5:

There is no known subsurface material containing residual radioactivity in the proximity of the ISFSI that will require remediation to meet the criteria for license termination.

Requirement 6:

"(6) A certification that financial assurance for decommissioning has been provided in the amount of the cost estimate for decommissioning."

Information for Requirement 6:

STP Units 1 and 2 owners have provided financial assurance for decommissioning the ISFSI site in an amount that meets or exceeds their respective ownership shares of the amount required by 10 CFR 50.75(b), which pursuant to 10 CFR 72.30(e)(5) provides the requisite financial assurance for the ISFSI decommissioning cost.

NOC-AE-18003592 Enclosure 2 Decommissioning Cost Estimate

NOC-AE-18003592 Enclosure 2 Page 1 of 12 South TeaMsStwcSeaf'GcnerttSin^Siatiw Dwwmcnl S30-174 J-SHl, Stv. a ffccffmmisswn.ias Cost analysis ApyenSix Gy JPes-se £of£ Table G South. Texas Project Nuclear Generating- Station ISFSI Decommissionmg- Cost Estunate (thousands of 2018 dollars)

Burial Oversisflit LLRW Total Hemoval Pa.clz&gittg Transport Other Volume aad Di&i?sal Craft Hours Costs Costs Costs Coats Coats Class A Contractor Costs (cubic feet) Hours Activity Description Decoiumissionmgf Contractor Plaziunxg' (cKara.cteiizatioa^. sp&cs ami proced.i.B'es) 474 474 1,312 DecQntammafion (onrerpacfc. dxspositiant) 2S4 261 622 8,097 42 9.307 72.867 3.141 License Tea-xamati.'oai (raolaological s'aryeys) 2.158 2.158 V^SA Subtotol 2S4 261 622 S.097 -2^7T ILSS9 72.867 "20.8S5 1.312 Sapportmsf Coats NRC and NEC Contractor Fees amd Costs 520 .520 1.153 Instmmce 213 213 Matagorda Cousty Tax 32 32 Matagorcb County Hospital Disaicc Tax 32 32 Security StafE Cost 636 636 24.S92 Oreisight StatE 344 344 4.419 Subtotal 1.778 1.778 30.464 Total (Wo continsfency) ~2Si "26T 622 ~sWf "4,452' 13,716 72,867 'WS6S 3U76 Total (w/25<a contui&*<acy) ^55~ '326' ~77S- 10.1.21 ~~53? 17JL45 Tlie application crfcontmgencr (25*.) ia consistent with the evaluation criterta referenced by tile KBC in KTJSEG-17B'; (*ConsoUdat>>d Decommissioning Gmdance.

TmaacialAssuraacer "KecordlEeephi^ And Timj&liness,"'U.S^ 'N'RC's Office ofNudfcar Matertal Safety aad. Saf&^uards,. NTJKEG-17S7, VoL 3. .Rev. I* .February -2012) 7LG Services Inc.

NOC-AE-18003592 Enclosure 2 Page 2 of 12 Information for Requirement 3:

The following information is extracted from TLG Services, Inc. decommissioning estimates for South Texas Project (STP) Units 1 and 2.

3.0 Cost Estimate The cost estimate prepared for decommissioning the STP considers the unique features of the plant, including the nuclear steam supply system, power generation systems, support services, plant structures, and ancillary facilities. The basis of the estimate, including the sources of information relied upon, the estimating methodology employed, site-specific considerations, and other pertinent assumptions, is described in this section.

3.1 BASIS OF COST ESTIMATE The analysis relies upon site-specific, technical information from an evaluation prepared in 2012-13, updated to reflect current assumptions pertaining to the operating life of the reactors, disposition of the nuclear units and relevant industry experience in undertaking such projects. The costs are based on several key assumptions in areas of regulation, component characterization, high-level radioactive waste management, low-level radioactive waste disposal, performance uncertainties (contingency) and site restoration requirements.

3.2 METHODOLOGY The methodology used to develop the estimates follows the basic approach originally presented in the AIF/NESP-036 study report, "Guidelines for Producing Commercial Nuclear Power Plant Decommissioning Cost Estimates," and the Department of Energy (DOE) "Decommissioning Handbook." These documents present a unit factor method for estimating decommissioning activity costs, which simplifies the estimating calculations. Unit factors for concrete removal ($/cubic yard),

steel removal ($/ton), and cutting costs ($/inch) are developed using local labor rates. The activity-dependent costs are estimated with the item quantities (cubic yards and tons), developed from plant drawings and inventory documents. Removal rates and material costs for the conventional disposition of components and structures rely upon information available in the industry publication, "Building Construction Cost Data," published by R.S.Means.

The unit factor method provides a demonstrable basis for establishing a reliable cost estimate. The detail provided in the unit factors, including activity duration, labor costs (by craft), and equipment and consumable costs, ensures that essential elements have not been omitted.

This analysis reflects lessons learned from TLG's involvement in the Shippingport Station Decommissioning Project, completed in 1989, as well as the decommissioning of the Cintichem reactor, hot cells, and associated facilities, completed in 1997. In addition, the planning and engineering for the Rancho Seco, Trojan, Yankee Rowe, Big Rock Point, Maine Yankee, Humboldt Bay-3, Oyster Creek, Connecticut Yankee, Crystal River, Vermont Yankee and Fort Calhoun nuclear units have provided additional insight into the process, the regulatory aspects, and the technical challenges of decommissioning commercial nuclear units.

NOC-AE-18003592 Enclosure 2 Page 3 of 12 Work Difficultv Factors The estimate follows the principles ofALARA through the use of work duration adjustment factors.

These factors address the impact of activities such as radiological protection instruction, mock-up training, and the use of respiratory protection and protective clothing. These factors lengthen a task's duration, increasing costs and lengthening the overall schedule. ALARA planning is considered in the costs for engineering and planning, and in the development of activity specifications and detailed procedures. Changes to worker exposure limits may impact the decommissioning cost and project schedule.

Work difficulty adjustment factors (WDFs) account for the inefficiencies in working in a power plant environment. The factors are assigned to each unique set of unit cost factors, commensurate with the inefficiencies associated with working in confined, hazardous environments. The ranges used for the WDFs are as follows:

  • Access Factor 10% to 20%
  • Respiratory Protection Factor 10% to 50%
  • Radiation/ALARA Factor 10% to 37%
  • Protective Clothing Factor 0% to 30%
  • Work Break Factor 8.33%

The factors and their associated range of values were developed in conjunction with the AIF/NESP-036 study. The application of the factors is discussed in more detail in that publication.

Scheduling Program Durations The unit factors, adjusted by the WDFs as described above, are applied against the inventory of materials to be removed in the radiological controlled areas. The resulting man-hours, or crew-hours, are used in the development of the decommissioning program schedule, using resource loading and event sequencing considerations. The scheduling of conventional removal and dismantling activities is based upon productivity information available from the "Building Construction Cost Data" publication. Dismantling of fuel handling building systems and decontamination of the spent fuel pools are also dependent upon the timetable for the transfer of the spent fuel assemblies from the pools to the ISFSI.

An activity duration critical path is used to determine the total decommissioning program schedule.

The schedule is relied upon in calculating the carrying costs, which include program management, administration, field engineering, equipment rental, and support services such as quality control and security. This systematic approach for assembling decommissioning estimates ensures a high degree of confidence in the reliability of the result.

3.3 IMPACT OF DECOMMISSIONING MULTIPLE REACTOR UNITS In estimating the near simultaneous decommissioning of two co-located reactor units there can be opportunities to achieve economies of scale, by sharing costs between units, and coordinating the sequence of work activities. There will also be schedule constraints, particularly where there are requirements for specialty equipment and staff, or practical limitations on when final status surveys can take place. For purposes of the estimate, Units 1 and 2 are assumed to be essentially identical.

Common facilities have been assigned to Unit 2. A summary of the principal impacts are listed below.

NOC-AE-18003592 Enclosure 2 Page 4 of 12 The sequence of work generally follows the principle that the work is done at STP Unit 1 first, followed by similar work at STP Unit 2. This permits the experience gained at Unit 1 to be applied by the workforce at the second unit. It should be noted however, that the estimate does not consider productivity improvements at the second unit, since there is little documented experience with decommissioning two units simultaneously. The work associated with developing activity specifications and procedures can be considered essentially identical between the two units, therefore the second unit costs are assumed to be a fraction of the first unit (~ 40%).

The segmentation of STP Unit 2 reactor vessel internals and vessel shell was scheduled to follow the same activities at Unit 1. The cost of additional specialty equipment was included for STP Unit 2 so that there was no delay in sequencing work between the units.

Some program management and support costs, particularly costs associated with the more senior positions, can be avoided with two reactors undergoing decommissioning simultaneously. As a result, the estimate is based on a "lead" unit that includes these senior positions, and a "second" unit that excludes these positions. The designation as lead is based on the unit undertaking the most complex tasks (for instance vessel segmentation) or performing tasks for the first time.

The final radiological survey schedule is also affected by a two-unit decommissioning schedule. It would be considered impractical to try to complete the final status survey of STP Unit 1, while STP Unit 2 still has ongoing radiological remediation work and waste handling in process. As a result, STP Unit 1 is assumed to enter a delay period after completion of radiological remediation, such that the final status survey can be completed for the station.

During this delay, program management costs are reduced accordingly.

The final demolition of buildings at STP Units 1 and 2 are considered to take place concurrently. This is considered a reasonable assumption since access to the buildings is considered good at the station.

STP Unit 1, as the first unit to enter decommissioning, incurs the majority of site characterization costs.

Shared systems and structures are generally assigned to STP Unit 2.

Station costs such as ISFSI operations, emergency response fees, regulatory agency fees, corporate overhead, and insurance are generally allocated on an equal basis between the two units.

NOC-AE-18003592 Enclosure 2 Page 5 of 12 3.4 FINANCIAL COMPONENTS OF THE COST MODEL TLG's proprietary decommissioning cost model, DECCER, produces a number of distinct cost elements. These direct expenditures, however, do not comprise the total cost to accomplish the project goal (license termination and site restoration).

3.4.1 Contingency Inherent in any cost estimate that does not rely on historical data is the inability to specify the precise source of costs imposed by factors such as tool breakage, accidents, illnesses, weather delays, and labor stoppages. In the DECCER cost model, contingency fulfills this role. Contingency is added to each line item to account for costs that are difficult or impossible to develop analytically.

Such costs are historically inevitable over the duration of a job of this magnitude; therefore, this cost analysis includes funds to cover these types of expenses.

The activity- and period-dependent costs are combined to develop the total decommissioning cost.

A contingency is then applied on a line-item basis, using one or more of the contingency types listed in the AIF/NESP-036 study. "Contingencies" are defined in the American Association of Cost Engineers "Project and Cost Engineers' Handbook" as "specific provision for unforeseeable elements of cost within the defined project scope; particularly important where previous experience relating estimates and actual costs has shown that unforeseeable events which will increase costs are likely to occur." The cost elements in this analysis are based upon ideal conditions and maximum efficiency; therefore, consistent with industry practice, contingency is included. In the AIF/NESP-036 study, the types of unforeseeable events that are likely to occur in decommissioning are discussed and guidelines are provided for percentage contingency in each category. It should be noted that contingency, as used in this analysis, does not account for price escalation and inflation in the cost of decommissioning over the anticipated operating life of the station.

Contingency funds are an integral part of the total cost to complete the decommissioning process.

Exclusion of this component puts at risk a successful completion of the intended tasks and, potentially, subsequent related activities. For this study, TLG examined the major activity related problems (decontamination, segmentation, equipment handling, packaging, transport, and waste disposal) that necessitate a contingency. Individual activity contingencies ranged from 10% to 75%,

depending on the degree of difficulty judged to be appropriate from TLG's actual decommissioning experience. The contingency values used in this study are consistent with those developed in the AIF/NESP-036 study and are as follows:

  • Decontamination 50%
  • Contaminated Component Removal 25%
  • Contaminated Component Packaging 10%
  • Contaminated Component Transport 1 5%
  • Low-Level Radioactive Waste Disposal 25%
  • Low-Level Radioactive Waste Processing 15%
  • Reactor Segmentation 75%
  • Nuclear Steam Supply System (NSSS) Component Removal 25%
  • Reactor Waste Packaging 25%
  • Reactor Waste Transport 25%
  • Reactor Vessel Component Disposal 50%
  • Greater-Than-Class C (GTCC) Disposal 15%
  • Non-Radioactive Component Removal 15%
  • Heavy Equipment and Tooling 15%
  • Supplies 25%

NOC-AE-18003592 Enclosure 2 Page 6 of 12

  • Engineering 15%
  • Energy 15%
  • Insurance and Fees 10%
  • Characterization and Termination Surveys 30%
  • Operations and Maintenance Expense 15%
  • Property Taxes 0%
  • ISFSI Decommissioning 25%

The contingency values are applied to the appropriate components of the estimate on a line item basis. A contingency of 25% is applied to the subtotal of the ISFSI decommissioning costs.

3.4.2 Financial Risk In addition to the routine uncertainties addressed by contingency, another cost element that is sometimes necessary to consider when bounding decommissioning costs relates to uncertainty, or risk. Examples can include changes in work scope, pricing, job performance, and other variations that could conceivably, but not necessarily, occur. Consideration is sometimes necessary to generate a level of confidence in the estimate, within a range of probabilities. TLG considers these types of costs under the broad term "financial risk." Included within the category of financial risk are:

  • Transition activities and costs: ancillary expenses associated with eliminating 50% to 80% of the site labor force shortly after the cessation of plant operations, added cost for worker separation packages throughout the decommissioning program, national or company-mandated retraining, and retention incentives for key personnel.
  • Delays in approval of the decommissioning plan due to intervention, public participation in local community meetings, legal challenges, and national and local hearings.
  • Changes in the project work scope from the baseline estimate, involving the discovery of unexpected levels of contaminants, contamination in places not previously expected, contaminated soil previously undiscovered (either radioactive or hazardous material contamination), variations in plant inventory or configuration not indicated by the plant drawings.
  • Regulatory changes, for example, affecting worker health and safety, site release criteria, waste transportation, and disposal.
  • Policy decisions altering national commitments (e.g., in the ability to accommodate certain waste forms for disposition), or in the timetable for such, for example, the start and rate of acceptance of spent fuel by the DOE.
  • Pricing changes for basic inputs such as labor, energy, materials, and disposal.

NOC-AE-18003592 Enclosure 2 Page 7 of 12 This cost study, however, does not add any additional costs to the estimate for financial risk, since there is insufficient historical data from which to project future liabilities. Consequently, the areas of uncertainty or risk should be revisited periodically and addressed through repeated revisions or updates of the base estimate.

3.5 SITE-SPECIFIC CONSIDERATIONS There are a number of site-specific considerations that affect the method for dismantling and removal of equipment from the site and the degree of restoration required. The cost impact of the considerations identified below is included in this cost study, 3.5.1 Spent Fuel Management The cost to dispose the spent fuel generated from plant operations is not reflected within the estimate to decommission the STP nuclear units. Ultimate disposition of the spent fuel is within the province of the DOE'S Waste Management System, as defined by the Nuclear Waste Policy Act. As such, the disposal cost is financed by a surcharge paid into the DOE'S waste fund during operations.

On November 19, 2013, the U.S. Court of Appeals for the D.C. Circuit ordered the Secretary of the Department of Energy to suspend collecting annual fees for nuclear waste disposal from nuclear power plant operators until the DOE has conducted a legally adequate fee assessment.

The NRC does, however, require licensees to establish a program to manage and provide funding for the management of all irradiated fuel at the reactor site until title of the fuel is transferred to the Secretary of Energy. This requirement is addressed through the inclusion of certain high-level waste cost elements within the estimates, as described below.

Completion of the decommissioning process is dependent upon the DOE'S ability to remove spent fuel from the site in a timely manner. Today, the country is at an impasse on high-level waste disposal, even with the License Application for a geologic repository submitted by the DOE to the NRC in 2008. The Obama administration cut the budget for the repository program while promising to "conduct a comprehensive review of policies for managing the back end of the nuclear fuel cycle and make recommendations for a new plan." While an interim storage facility could be developed, the siting process could be protracted. As such, for purposes of this analysis, the spent fuel management plan for STP spent fuel assumes that the DOE will be able to complete the transfer of spent fuel within 60 years of the cessation of final operations, i.e., by 2108.

ISFSI Due to DOE'S inability to remove fuel from the site, an ISFSI will be constructed at the site and fuel casks have been emplaced thereon to support continued plant operations. This analysis includes the cost to construct (and expand) an ISFSI to support continued plant operations, as well as to facilitate the decommissioning of the two nuclear units. The ISFSI is assumed to be sized (or supplemented) so as to accommodate the spent fuel generated over the 60 years of operations (assuming no DOE pickup will occur during this period).

The capital costs for ISFSI construction/expansion, as well as for the dry storage systems for the spent fuel generated during plant operations that cannot be accommodated in the plant's wet storage pools (i.e., through the years 2047/2048), are reported as pre-shutdown costs.

NOC-AE-18003592 Enclosure 2 Page 8 of 12 Storaoe Canister Design The design and capacity of the ISFSI is based upon the Holtec HI-STORM FW dry cask storage system. The system consists of a multipurpose canister (MPC) with a nominal capacity of 37 fuel assemblies and a concrete storage overpack.

Canister Loading and Transfer The estimate includes the cost for the labor and equipment to load and transfer the multi-purpose canisters from the pools to the ISFSI. For estimating purposes, an allowance is used for the cost to eventually transfer the fuel from the ISFSI into the DOE transport cask.

Operations and_Maintena_nce The estimate includes the post-shutdown cost of operating and maintaining the spent fuel pools and the ISFSI. Pool operations are expected to continue approximately five and one half years after the cessation of operations at each unit. It is assumed that the five and one-half years provides the necessary cooling period for the final core to meet the decay heat requirements for the dry cask storage system. ISFSI operating costs are based upon the previously stated assumptions on fuel transfer expectations.

Post-shutdown costs include the containerization and transfer of the spent fuel in the reactor and pools at shutdown, for each unit, to the ISFSI over the five and one-half years of post-shutdown pool operations, the operation of the ISFSI, including the periodic transfer of the spent fuel to the DOE from this facility to an off-site location (e.g., an interim storage facility), and the eventual decommissioning of the ISFSI. It does not include any costs related to the final disposal of the spent fuel.

ISFSI operating costs include staffing, as well as security, insurance, and licensing fees.

IS FS I Decommissioninci In accordance with 10 CFR §72.30, licensees must have a proposed decommissioning plan for the ISFSI site and facilities that includes a cost estimate for the plan. The plan needs to contain sufficient information on the proposed practices and procedures for the decontamination of the ISFSI and for the disposal of residual radioactive materials after all spent fuel, high-level radioactive waste, and reactor-related GTCC waste have been removed.

The dry storage vendor does not expect the concrete casks to have any interior or exterior radioactive surface contamination. Any neutron activation of the steel and concrete is also expected to be extremely small. However, the decommissioning estimate is based on the premise that some of the concrete casks will contain low levels of neutron-induced residual radioactivity that would necessitate remediation at the time of decommissioning. As an allowance, 12 casks are assumed to be affected, i.e., contain residual radioactivity. The allowance is based upon the number of casks required for the final core off-load (i.e., 193 offloaded assemblies per unit, 37 assemblies per cask) which results in 6 overpacks per unit. It is assumed that these are the final casks offloaded; consequently they have the least time for radioactive decay of any neutron activation products.

No contamination or activation of the ISFSI pad is assumed. 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. As such, only verification surveys are included for the pad in the decommissioning estimate. The estimate is limited to costs necessary to terminate the ISFSI's NRC license and meet the §20.1402 criteria for unrestricted use.

NOC-AE-18003592 Enclosure 2 Page 9 of 12 In accordance with the specific requirements of 10 CFR §72.30 for the ISFSI work scope, the cost estimate for decommissioning the ISFSI reflects: 1) the cost of an independent contractor performing the decommissioning activities; 2) an adequate contingency factor; and 3) the cost of meeting the criteria for unrestricted use. The cost summary for decommissioning the ISFSI is presented in Appendix G.

GTCC The dismantling of the reactor internals is expected to generate radioactive waste considered unsuitable for shallow land disposal (i.e., low-level radioactive waste with concentrations of radionuclides that exceed the limits established by the NRC for Class C radioactive waste (GTCC)). The Low-Level Radioactive Waste Policy Amendments Act of 1985 assigned the federal government the responsibility for the disposal of this material. The Act also stated that the beneficiaries of the activities resulting in the generation of such radioactive waste bear all reasonable costs of disposing of such waste. Although the DOE is responsible for disposing of GTCC waste, any costs for that service have not been determined. For purposes of this estimate, the GTCC radioactive waste has been assumed to be packaged in the same canisters used to store spent fuel and disposed of as. high-level waste, at a cost equivalent to that envisioned for the spent fuel. The number of canisters required and the packaged volume for GTCC was based upon experience at Maine Yankee (e.g., the constraints on loading as identified in the canister's certificate of compliance).

It is assumed only for purposes of these estimates that the DOE would not accept this waste prior to completing the transfer of spent fuel. Therefore, until such time as the DOE is ready to accept GTCC waste, it is assumed that this material would remain in storage at the STP site. It is acknowledged, however, that the plant owners will seek the most expeditious means of removing GTCC from the site when DOE commences performance.

3.6 ASSUMPTIONS The following are the major assumptions made in the development of the estimate for decommissioning the STP ISFSI.

3.6.1 Estimating Basis Decommissioning costs are reported in the year of projected expenditure; however, the values are provided in 2018 dollars. Costs are not inflated, escalated, or discounted over the periods of performance.

The estimates rely upon the physical plant inventory that was the basis for the 2012-13 analysis (updated to reflect any significant changes to the plant over the past six years).

The study follows the principles of ALARA through the use of work duration adjustment factors.

These factors address the impact of activities such as radiological protection instruction, mock-up training, and the use of respiratory protection and protective clothing. The factors lengthen a task's duration, increasing costs and lengthening the overall schedule. ALARA planning is considered in the costs for engineering and planning, and in the development of activity specifications and detailed procedures. Changes to worker exposure limits may impact the decommissioning cost and project schedule.

3.6.2 Labor Costs STP Nuclear Operating Company, as the operator, will continue to provide site operations support:,

including decommissioning program management, licensing, radiological protection, and site security.

NOC-AE-18003592 Enclosure 2 Page 10 of 12 Security, while reduced from operating levels, is maintained throughout the decommissioning for access control, material control, and to safeguard the spent fuel (in accordance with the requirements of 10 CFR Part 37, Part 72, and Part 73). A minor reduction in the site security levels is assumed once the reactor(s) have been defueled. There are no further staff reductions until all irradiated fuel has been relocated to the ISFSI.

A Decommissioning Operations Contractor (DOC) will provide the supervisory staff needed to oversee the labor subcontractors, consultants, and specialty contractors needed to perform the work required for the decontamination and dismantling effort. The DOC will also provide the engineering services needed to develop activity specifications, detailed procedures, detailed activation analyses, and support: field activities such as structural modifications.

Personnel costs are based upon average salary information provided by STP Nuclear Operating Company. Overhead costs are included for site and corporate support, reduced commensurate with the staffing of the project.

Reduction in the operating organization is assumed to be handled through normal company human resource practices (e.g., reassignment and outplacement). An allowance is included for severance for the plant's operating staff.

The craft labor required to decontaminate and dismantle the nuclear units will be acquired through standard site contracting practices. The current cost of labor at the site is used as an estimating basis.

3.6.3 Design Conditions Any fuel cladding failure that occurred during the lifetime of the plant is assumed to have released fission products at sufficiently low levels that the buildup of quantities of long-lived isotopes (e.g.,

137Cs, 9°Sr, or transuranics) has been prevented from reaching levels exceeding those that permit the major NSSS components to be shipped under current transportation regulations and disposal requirements.

The curie contents of the vessel and internals at final shutdown are derived from those listed in "Long-Lived Activation Products in Reactor Materials" (NUREG/CR-3474). Actual estimates are derived from the curie/gram values contained therein and adjusted for the different mass of STP components, projected operating life, and different periods of decay. Additional short-lived isotopes were derived from "Technology, Safety and Costs of Decommissioning a Reference Pressurized Water Reactor Power Station" (NUREG/CR-0130) and "Technology, Safety and Costs of Decommissioning a Reference Boiling Water Reactor Power Station - Main Report" (NUREG/CR-0672), and benchmarked to the long-lived values from NUREG/CR-3474.

The control elements are disposed of along with the spent fuel (i.e., there is no additional cost provided for their disposal). Disposition of any control elements stored in the pools from operations is considered an operating expense and therefore not accounted for in the decommissioning estimate.

NOC-AE-18003592 Enclosure 2 Page 11 of 12 3.6.4 General Transition Activities Existing warehouses are cleared of non-essential material and remain for use by the plant operator and its subcontractors. The plant's operating staff performs the following activities at no additional cost or credit to the project during the transition period.

  • Drain and collect fuel oils, lubricating oils, and transformer oils for recycle and/or sale.
  • Drain and collect acids, caustics, and other chemical stores for recycle and/or sale.
  • Process operating waste inventories. This estimate does not address the disposition of any legacy wastes and the disposal of operating wastes during this initial period is not considered a decommissioning expense. ,

Scrap and Salvage The existing plant equipment is considered obsolete and suitable for scrap as deadweight quantities only. The STP Nuclear Operating Company will make economically reasonable efforts to salvage equipment following final plant shutdown. However, dismantling techniques assumed for equipment in this analysis are not consistent with removal techniques required for salvage (resale) of equipment.

Experience has indicated that some buyers wanted equipment stripped down to very specific requirements before they would consider purchase. This required expensive rework after the equipment had been removed from its installed location. Since placing a salvage value on this machinery and equipment would be speculative, and the value would be small in comparison to the overall decommissioning expenses, this analysis does not attempt to quantify the value that an owner may realize based upon those efforts.

It is assumed, for purposes of this analysis, that any value received from the sale of scrap generated in the dismantling process would be more than offset by the on-site processing costs. The dismantling techniques assumed in the decommissioning estimate do not include the additional cost for size reduction and preparation to meet "furnace ready" conditions. With a volatile market, the potential profit margin in scrap recovery is highly speculative, regardless of the ability to free release this material. An allowance has been included for the survey and release of all metallic material released from the site.

Furniture, tools, mobile equipment such as forklifts, trucks, bulldozers, and other property is removed at no cost or credit to the decommissioning project. Disposition may include relocation to other facilities. Spare parts are also made available for alternative use.

Enerc For estimating purposes, the plant is assumed to be de-energized, with the exception of those facilities associated with spent fuel storage (temporary power is run throughout the plant, as needed). Replacement power costs are used to calculate the cost of energy consumed during decommissioning for tooling, lighting, ventilation, and essential services.

Jnsyrance Costs for continuing coverage (nuclear liability and property insurance) following cessation of plant operations and during decommissioning are included and based upon current operating premiums.

Reductions in premiums, throughout the decommissioning process, are based upon the guidance

NOC-AE-18003592 Enclosure 2 Page 12 of 12 and the limits for coverage defined in the NRC's proposed rulemaking "Financial Protection Requirements for Permanently Shutdown Nuclear Power Reactors" (Federal Register 58690), dated 10/30/97. The NRC's financial protection requirements are based on various reactor (and spent fuel) configurations.

Property Taxes and Emergency Response Fees Matagorda County and Matagorda County Hospital District taxes and fees are included in the total decommissioning costs. Current revenue caps are maintained through the first year following the permanent cessation of operations for each unit. Taxes and fees are reduced by 50% each following year until the combined, annual revenue level equals approximately one hundred thousand dollars.

This nominal payment is maintained through the active decommissioning period and until such time that the transfer of spent fuel to the DOE is completed.

Where costs are allocated by ownership share, property taxes are assigned solely to NRG South Texas because the other two STP owners, CPS Energy and City of Austin, are exempt from paying real property taxes. All three owners contribute to certain other fees for community support for plant operations.

Contingency is not applied to Matagorda County and Matagorda County Hospital District taxes and fees.

Emeroency Planning FEMA and state emergency planning fees continue for approximately 18 months after the cessation of plant operations. At that time, the fees are discontinued. The timing is based upon the anticipated condition of the spent fuel (i.e., the hottest spent fuel assemblies are assumed to be cool enough that no substantial Zircaloy oxidation and off-site event would occur with the loss of spent fuel pool water). Local fees continue until all fuel has been moved from the pool into dry storage (approximately five and one-half years following the cessation of operations).

SalesTax The costs include sales tax on only that portion of the purchases made by NRG South Texas. The other STP owners, CPS Energy and City of Austin, are exempt from paying sales taxes.

Environmental The cost estimates include the remediation of the firing range (disposal of lead-contaminated soil) and the sampling of several material storage areas, spoil piles, septic fields, and other potentially affected areas.

Site Modifications The perimeter fence and in-plant security barriers will be moved, as appropriate, to conform to the site security plan in force during the various stages of the project.

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