ML23286A306

Safety Evaluation Report Related to the Partial Site Release

ML23286A306
Person / Time
Site:	Zion  File:ZionSolutions icon.png
Issue date:	11/08/2023
From:	Reactor Decommissioning Branch
To:
References
Download: ML23286A306 (46)

Text

SAFETY EVALUATION REPORT RELATED TO THE PARTIAL SITE RELEASE FROM FACILITY OPERATING LICENSES NOS. DPR-39 AND DPR-48 ZIONSOLUTIONS, LLC ZION NUCLEAR POWER STATION, UNIT NOS. 1 AND 2 DOCKET NOS. 50-295, 50-304, AND 72-1037 BACKGROUND Facility Location The Zion Nuclear Power Station (ZNPS or Zion), Unit Nos. 1 and 2, is located near the city of Zion in northeast Illinois on the west shore of Lake Michigan. The site is approximately 40 miles north of Chicago, Illinois and 42 miles south of Milwaukee, Wisconsin. In September 1996, Zion, Unit No. 2, was permanently shut down after approximately 23 years of operation. In February 1997, Zion Unit No. 1, was permanently shut down after approximately 24 years of operation. On February 13, 1998 (Agencywide Document Access and Management System (ADAMS) Main Library (ML) Accession No. ML15232A492), in accordance with Title 10 of the Code of Federal Regulations (10 CFR) 50.82(a)(1)(i),

Commonwealth Edison Company (ComEd) notified the Nuclear Regulatory Commission (NRC) of the permanent cessation of operations at the Zion site. On March 9, 1998 (ML15232A487), in accordance with 10 CFR 50.82 (a)(1)(ii), ComEd provided written certification that all spent fuel assemblies were permanently removed from the reactor vessels to the spent fuel pool (SFP).

License Transfers The Commission has issued Amendment No. 181 to Facility Operating License No. Demonstration Power Reactor (DPR) DPR-39 (Zion Unit No. 1) and Amendment No. 168 to Facility Operating License DPR-48 (Zion Unit No. 2) respectively, on January 12, 2001 (ML010190275). The conforming amendments reflected the transfer of ComEds ownership of these units from ComEd to Exelon Generation Company, LLC (EGC). The safety evaluation (ML003738280) supporting the Zion conforming amendments was enclosed with the Order applicable to the Zion site (ML003738276) issued on August 3, 2000.

By letter dated September 1, 2010, the NRC transferred Facility Operating Licenses Nos. DPR-39 and DPR-48 from EGC to EnergySolutions, subsidiary, ZionSolutions, LLC (ZS) (ML102290437). The Zion site was acquired by ZS to conduct the decommissioning of the facility, excluding the decommissioning of the on-site Independent Spent Fuel Storage Installation (ISFSI) and then return the decommissioned site and the generally licensed on-site ISFSI back to EGC. In this first-of-a-kind arrangement, EGC agreed to transfer the Zions licenses to decommissioning contractor Energy Solutions. The transfer, which was approved by the NRC, meant that EnergySolutions acquired all of the Zions assets and then worked as owner and licensee while it dismantled the plant. Energy Solutions then processed and disposed of all the low-level radioactive waste from the site at its facility at Clive, Utah, and placed Zion's used nuclear fuel in NRC-approved dry cask storage containers. The used fuel remains EGCs property and remains on the site in a secure facility. Once decommissioning of the Zion site was complete, the licenses are to transfer back to EGC per the agreement.

ENCLOSURE

ZS believed that it was on track to complete all decommissioning by 2020 and in preparation for returning the licenses back to EGC, on July 24, 2018 (ML18211A303), ZS and EGC requested, that the NRC consent to the transfer of ZSs authorities and responsibilities under the licenses back to EGC so as to implement ZSs transfer to EGC of the assets comprising the Zion (with the exception of the real estate encompassing the Zion site, 345 KV switchyard, certain other improvements, and the spent nuclear fuel and the Greater Than Class C (GTCC) waste, title to all of which were retained by EGC at the time of the prior transfer of the licenses from EGC to ZS). On November 26, 2019 (ML19228A130), the NRC issued a permissive Order (Transfer Order) approving the transfer and approving draft conforming administrative license amendments and the Order has a condition that requires, among other things, that the decommissioning and license termination activities must be completed before the transfer can occur. The Transfer Order was intended to be implemented upon the completion of decommissioning activities at the Zion site and was effective for 1 year from its date of issuance. The licensee requested extension four times (ML20248H452, ML21112A164, ML21230A322, ML22294A162), and the effective date of the Order was extended four times by Order (ML20259A469, ML21110A606, ML21229A027, and ML22308A177) because decommissioning was not completed. The direct license Transfer Order expires on November 26, 2023.

Since the November 26, 2019, Order approving the direct license transfer, EGC underwent an indirect license transfer that involves the Zion licenses by Order (ML21277A192), which resulted in a new company, Constellation Energy Generation, LLC (CEG). The conforming amendments were issued but did not include the Zion licenses, as requested, because the decommissioning of the Zion site was not completed as stipulated in a condition 1. 0F In addition, the NRC consented to an indirect license transfer of control of Zion licenses by Order (ML22076A008 Pkg), separate from the indirect license transfer noted above, to the extent that the licenses may be held by the Applicant or the Licensed Subsidiaries at the time of the indirect license transfer. Specifically, the NRC consented to support a proposed stock purchase agreement dated November 16, 2021, in which TriArtisan ES Partners II LP, established by TriArtisan ES Partners, LLC, TriArtisan ES MM LLC, and TriArtisan Capital Advisors LLC, acquired majority ownership of Rockwell Holdco, Inc. (Rockwell), the upstream owner of the Licensed Subsidiaries.

This indirect license Transfer Order is subject to condition no. 2 2 to address the pending direct 1F license transfer condition for the Zion licenses as described in the November 26, 2019, Direct license Transfer Order, as discussed above.

Partial Site Release Requests A partial site release (PSR) of non-impacted areas occurred in 2016. By letter dated August 27, 2015 (ML15243A029), as supplemented by letter dated January 26, 2016 (ML16028A192), ZS submitted a request to the NRC for a PSR at Zion. The proposed action requested the removal and release of the portions of the site (214 acres) which had been classified as radiologically non-impacted by its 10 CFR Part 50 licenses. In accordance with 10 CFR 50.83, the NRC staff 1 If EGC does not hold Facility Operating License Nos. DPR-39 and DPR-48 for Zion, Unit Nos. 1 and 2, respectively, and the general license for the Zion ISFSI at the time of the closing of the spin transaction, then these licenses shall not be transferred to SpinCo as part of the Spin transaction.

2 If EnergySolutions does not indirectly hold Facility Operating License Nos. DPR-39 and DPR-48 for ZNPS, Units 1 and 2, respectively, and the general license for the ZNPS ISFSI, at the time of the closing of the proposed indirect license transfer, then the ZNPS licenses shall not be transferred as part of the indirect license transfer.

2

reviewed the overall effects that the release would have on public exposures and whether the classification of the release as non-impacted was justified. The NRC also held a public meeting on December 1, 2015, in the vicinity of Zion to obtain public comments associated with the PSR request. None of the public comments resulted in the NRC making changes to the review of the PSR request. On March 31, 2016 (ML16053A257), the NRC staff completed its review of the Zion PSR request and found the proposed release of the 214 acres acceptable.

On June 5, 2020 (ML20164A096), as supplemented on March 3, 2021 (ML21102A397), ZS submitted a PSR application (ML20164A096) for the Zion site, excluding the on-site ISFSI. This application was supplemented on March 31, 2021 (ML21102A397). In this request, ZS requested the removal of approximately 112 acres of land from the Zion reactor licenses. This requested PSR, if the NRC determines the criteria in 10 CFR 50.82(a)(11) are met, would reduce the licensed areas to the ISFSI, the ISFSI support building, and the ISFSI Warehouse. ZS states in its request that ZS intends to remove an area consisting of seven basement survey units (SUs), 116 open land SUs (including three below grade excavation SUs), and five buried pipe SUs from the licenses with the approved License Termination Plan (LTP) (ML18164A223 Pkg). With the previously PSR request that was found acceptable, the proposed action, if NRC finds it acceptable, would effectively terminate the Zion 10 CFR Part 50, Domestic Licensing of Production and Utilization Facilities, licenses outside the footprint for the remaining on-site ISFSI. The licensed area would then encompass approximately 5 acres (see Figure 2, Zion Site Boundaries).

Contamination Control and Cleanup of the Discrete Radioactive Particles (DRPs) at Zion In accordance with the approved LTP, ZS conducted Final Status Surveys (FSSs) to demonstrate that the facility and site meet the criteria for unrestricted release as presented in 10 CFR 20.1402. During the review of the FSS reports, it was identified that DRPs were released into the environment. The NRC staff concludes that the DRPs were generated during decommissioning and implementation of the approved LTP and were thus a cross contamination control issue and survey issue (ML23024A208). The NRC and licensee conducted extensive hand scanning and sample collection to identify and remove DRPs. The NRC staff also conducted a DRP dose assessment to risk-inform the NRC decisions regarding whether to find acceptable the unrestricted release of the Zion site outside the boundary of the ISFSI.

For details on the NRC staffs DRP dose assessment, refer to Attachment A, Particle Assessment for Zion Nuclear Power Station of this safety evaluation. Refer to Attachment B, Identified Discrete Radioactive Particles and Associated Cleanup Actions, for a summary of the DRP identification and their removal at Zion.

Applicable Documents Required by License License Termination Plan The Zion LTP license amendment request (LAR), which was submitted by ZS by letter dated December 19, 2014 (ML15005A330). The LAR was supplemented by letters dated February 26, 2015 (ML15061A230), November 12, 2015 (ML15344A344), March 8, 2016 (ML16081A010),

July 20, 2016 (ML16211A199), February 27, 2017 (ML17208A121), and July 20, 2017 (ML17215A098). Revision 2 of the LTP LAR was then submitted on February 7, 2018 (ML18052A857 and ML18052A530), and supplemented by letters dated April 10, 2018 (ML18103A016), and August 28, 2018 (ML18242A082). The Zion LTP, referred to as the Zion Station Restoration Project or ZSRP LTP by ZS, was approved by the NRC on September 28, 3

2018, via amendment nos. 191 (Zion, Unit No.1) and 178 (Zion, Unit No. 2) as documented in the staffs safety evaluation (ML18164A222). The approved LTP specified, among other things, how the licensee plans to confirm the extent and success of remediation through radiological surveys, as captured in the Final Status Survey Reports (FSSRs). In the NRC staffs evaluation of the PSR request, the NRC staff evaluates whether the decommissioning activities and the FSSs were conducted in accordance with the approved LTP.

Final Status Survey Submittals After ZS performed decommissioning activities and surveys, ZS submitted the FSSRs in phases as follows: Phase 1 specifically addresses ten (10) open land area SUs that total approximately 221,234 m2 in area; Phase 2 encompass remaining basement structures, embedded pipe, penetrations, and buried pipe; Phase 3 includes the open land SUs encompassing the southern portion of the site, and the Phase 4 encompasses the northern portion. The FSSRs are required per the LTP.

The FSSRs were submitted by ZS by letters dated November 1, 2018 (Phase 1) (ML18331A016 Pkg); June 21, 2019 (Phase I, Revision) (ML19178A109 Pkg); March 11, 2019 (Phase 2, Part 1)(ML19077A095 Pkg); September 30, 2019 (Phase 2) (ML19295G627 Pkg); November 25, 2019 (Phase 2, Part 2) (ML19338B809 Pkg); December 30, 2019 (Phase 3) (ML20009E643 Pkg);

February 29, 2020 (Zion Station Restoration Project FSS Final Report - Phase 1, Rev 2)

(ML20073F671), April 30, 2020 (For four Phase 3 SUs, Revision) (ML20147A092 Pkg); and May 1, 2020 (Phase 4) (ML20133J976 Pkg), as supplemented by letters dated May 15, 2020 (Requests for Additional Information (RAI) Response for Phases 2a, 2b, and 3) (ML20147A128); June 4, 2020 (RAI responses for Phases 2a, 2b, and 3) (ML20167A280); November 11, 2020 (RAI Response for Phases and Revised Phase 2, Part 2) (ML20351A154 Pkg); February 10, 2021 (Revised RAI Responses addressing sequencing of actions, inaccurate statements, survey completion, Oak Ridge Institute for Science and Education (ORISE) findings, controls post survey, corrective actions, condition reports, and discrete particles) (ML21067A225 Pkg); April 2, 2021 (Response to RAIs) (ML21103A229 Pkg); April 15, 2021 (RAI Response, Switchyard not included in Radiological Restricted Area (ML21112A166)) and May 11, 2021 (Clarification on the ISFSI Controlled Area Boundary (CAB)) (ML21131A072); August 4, 2022 (Revised SUs (ML22224A002 Pkg); September 30, 2022 (Final Status Survey Final Report - Phase 3 FSSR Rev. 1 and Final Status Survey Final Report - Phase 4 FSSR Rev. 2 (ML22279A984 Pkg); and October 27, 2023 (Further clarification on ISFSI CAB (ML23303A090). These submittals support the Zion PSR request received on June 5, 2020 (ML20164A096), as supplemented on March 3, 2021 (ML21102A397).

EVALUATION Applicable Requirements In accordance with 10 CFR 50.82(a)(11), the Commission shall terminate the license if it determines that: (i) the remaining dismantlement has been performed in accordance with the approved LTP, and (ii) the final radiation survey and associated documentation, including an assessment of dose contributions associated with non-impacted parts of the Zion site released for use before approval of the LTP, demonstrate that the facility and site have met the criteria for decommissioning in 10 CFR Part 20, Subpart E, Radiological Criteria for License Termination.

Zion has an on-site ISFSI under the general license in 10 CFR Part 72, Licensing Requirements for the Independent Storage of Spent Nuclear Fuel, High-Level Radioactive Waste, and Reactor-Related Greater Than Class C Waste. The Part 50 licenses cannot be terminated until all the 4

spent fuel and Greater-Then-Class C (GTCC) waste is permanently removed from the Zion site and the NRC approves amendments to the licenses to address the ISFSI decommissioning (LTP amendment) and finds the ISFSI decommissioning acceptable per the requirements of 10 CFR 20, Subpart E and the licenses. The present NRC staff evaluation includes everything except the ISFSI, ISFSI Support Building, and ISFSI Warehouse and surrounding land which encompasses approximately 5 acres.

In accordance with the approved LTP, ZS performed the Zion FSSRs for PSR for unrestricted use in accordance with its approved LTP. As identified in Table 2, Revision Column), ZS submitted all FSSR for radionuclides of concern (ROCs) that were acceptable to the NRC as documented in the NRC staffs FSSR safety evaluation.

As part of PSR approval after the LTP is approved, the NRC verifies that the site, except the ISFSI, meets acceptance levels. The NRC staff completed its evaluation of the FSSRs as referenced in Table 2, FSSRs and Corresponding NRC FSSR Acceptability. The following is the NRC staffs evaluation of all the submittals demonstrating the site meets the requirements for PSR of the Zion site.

Details of the FSS results were submitted to the NRC in four phases. Although the NRC staff identified some errors in FSSRs submitted after Amendment No. 191 and Amendment No. 178 effective date (amendments approving the LTP), the NRC staff noted that this did not have an impact for demonstrating compliance with the unrestricted release criteria. The NRC staff has completed its review of the Zion FSSRs to ensure that the removal of all SUs from the Zion Part 50 licenses demonstrates the ability of the site, in aggregate, to meet the criteria for unrestricted release contained in Subpart E, Radiological Criteria for License Termination, of 10 CFR Part 20, Standards for Protection Against Radiation. These evaluations have been documented in the NRC staffs safety evaluation that discuss the ZS errors and the NRC disposition of them.

Each survey unit and NRC safety evaluation report (SER) is referenced below in Table 2, FSSRs and Corresponding NRC FSSR Acceptability.

Below is the NRC staffs evaluation to determine whether all the SUs outside the ISFSI boundary meet the regulatory criteria for release from the Zion licenses. The NRC staff concludes that the release would be acceptable. The acceptability of the PSR would mean that all decommissioning of the site outside of the on-site ISFSI boundary is met. Completion of this decommissioning is a condition of the direct and two indirect license transfer Orders that are discussed above. Transfer of the Zion licenses from ZS to CEG of the assets comprising the Zion site (with the exception of the real estate encompassing the Zion site, 345 KV switchyard, certain other improvements, and the spent nuclear fuel and the GTCC waste, title to all of which were retained by Exelon at the time of the transfer of the licenses). The indirect license transfers include the transfer of the assets excepted from the direct license transfer for the Zion site and also is contingent upon the completion of the Zion decommissioning, among other things.

Remaining Dismantlement Activities In accordance with 10 CFR 50.82(a)(9)(ii)(B), Chapter 3 of the approved LTP provided a discussion of the remaining dismantlement activities necessary for PSR. These activities include site remediation and radiological FSSs. Chapter 4, Section 4.2.1 provides a corresponding description of the remediation considerations for each of the remaining structures, systems, and components.

In the approved LTP, ZS stated it planned to remediate the site, including structures, systems, and 5

components that remain on-site, to the criteria specified in 10 CFR Part 20, for unrestricted use. To meet these criteria, ZS planned to use typical remediation methods, which include structural surfaces include scabbling and shaving, chipping, sponge, and abrasive blasting, standard and pressure washing, wiping, grit blasting, mechanical fracturing and cutting, and other methods. ZS stated in its approved LTP that surface and subsurface soil with activity levels more than the Derived Concentration Guideline Level (DCGL) will be removed and disposed as radioactive waste.

Remediation of soils included the use of established excavation safety and environmental control procedures as well as appropriate work package instructions to ensure adequate erosion, sediment, and air emission controls during soil remediation.

As stated in the approved LTP, Chapter 5, and as evaluated by the NRC staff through inspection and FSS review, all structures associated with the Zion site were removed as described in Chapter 3 of the approved LTP, along with temporary decommissioning support trailers, except the following structures will remain:

• ISFSI

• ISFSI Support Building

• ISFSI Warehouse

• Other minor solid items, such as but not limited to the

• switchyard structures, the microwave tower,

• telephone poles,

• fencing,

• culverts,

• duct banks and

• electrical conduit.

ZS stated Chapter 5 of its approved LTP that the other minor solid items will be included in the open land FSSs in which they reside. Further, ZS states that major structures that will remain at license termination and be subjected to FSS, are the basements of the Unit No. 1 Containment Building, Unit No. 2 Containment Building, Auxiliary Building, Turbine Building, Waste Water Treatment Facility (WWTF), the lower portion of the Fuel Handling Building (FHB), including the SFP and the Fuel Transfer Canal, Crib House and Forebay, Unit No. 1 and Unit No. 2 Steam Tunnels and the Circulating Water Intake and Discharge Tunnels below the 588-foot elevation (3 feet below grade). All systems, components as well as all structures above the 588-foot elevation (except for the minor structures previously noted) will be removed during the decommissioning process and disposed of as a waste stream.

All concrete structures were removed to a depth of 3 feet below grade in accordance with the requirements of the Asset Sale Agreement. All remaining structures below 3 feet below grade were surveyed by ZS to demonstrate compliance with the unrestricted release criteria as specified in 10 CFR 20.1402.

As described in Chapter 3 of the approved LTP, underground circulating water heaters, discharge tunnels and buried service water piping running between the Crib House location and the Auxiliary Building were not removed. All remaining buried and piping embedded in concrete were surveyed for compliance with the unrestricted release criteria prior to being isolated, abandoned in place and filled with grout or fill as appropriate.

For the turbine buildings, auxiliary buildings, FHB, and the wastewater treatment facility once the remaining concrete structures located below three feet below grade were surveyed for compliance with the unrestricted release criteria, the buildings voids was backfilled using concrete debris 6

suitable for reuse as clean hard fill and/or clean fill to the original site grade and contours. The top 3 feet of fill was soil only.

Also, concrete debris resulting from the turbine building demolition that was designated for beneficial reuse as clean hard fill wase surveyed in accordance with the Multi-Agency Radiation Survey and Assessment of Materials and Equipment Manual (MARSAME) (NUREG-1575, Supplement 1) (74 FR 2998) and verified by ZS to be free of detectable radiation above background. This concrete debris was then processed to remove all exposed rebar and to ensure that individual debris pieces were smaller than 10 inches in diameter. The processed concrete debris was transported to a designated on-site storage area where it was stockpiled for use as backfill material.

Five 24-inch diameter sleeves that are buried in soil between each of the two Containments and the Auxiliary Building 542-foot elevation were surveyed for compliance with the unrestricted release criteria. They were then isolated, abandoned in place and filled with grout or fill as appropriate. Two of the five sleeves have been capped and were never used. The remaining three sleeves housed 20-inch diameter Recirculating Sump Suction lines which were removed prior to surveying and then the sleeves were abandoned in place after survey.

For the containment buildings, demolition of the structures progressed to three feet below grade.

After packing each containment basement with clean fill, both containment shells were demolished to a depth of three feet below grade in accordance with the requirements of the Asset Sale Agreement (in enclosure 1 to the January 25, 2008, license transfer application (ML080310521)). A detailed summary on what is to remain on-site is provided in Chapter 5 of the approved LTP, Revision 2, pages 5-1 and 5-2.

As noted above, ZS also had to complete FSSs. It detailed the results of those FSSs in FSSRs it submitted to the NRC staff. Refer to Table 2, FSSRs and Corresponding NRC FSSR Acceptability, for a complete listing of these submittals and the NRCs approvals with ADAMS Accession Nos. and document dates. The NRC staff has reviewed ZS FSSRs for Zion and determined that ZS has remediated the remaining structures, systems, and components consistent with Chapter 4, Section 4.2.1 of the approved LTP. Therefore, the NRC staff concludes that the dismantlement and decontamination activities have been completed in accordance with the approved LTP.

Final Status Survey The FSS is the radiation survey performed after an area has been fully characterized, remediation has been completed, and ZS believes that the area is ready to be released for unrestricted use. The purpose of the FSS is to demonstrate that the area meets the radiological criteria for license termination.

The NRC conducted performance-based in-process inspections of ZS FSS program during the decommissioning process. The purpose of the inspections was to verify that the FSSs were being conducted in accordance with the commitments made by ZS in the approved LTP, and to evaluate the quality of the FSSs by reviewing the FSS procedures, methodology, equipment, surveyor training and qualifications, document quality control, and survey data supporting the FSSRs. The NRC inspectors documented their findings in inspection reports.

Table 1, NRC inspection reports for Zion regarding FSSs, provides the ADAMS Accession No.

and document date for the relevant inspection reports. In addition, the NRC conducted numerous 7

independent confirmatory surveys to verify the FSS results obtained and reported by ZS. Refer to Table 4, Reports on Zion Regarding Confirmatory Surveys for Decommissioning, below, for a complete listing of confirmatory surveys performed with date and ADAMS Accession Nos.

Confirmatory surveys consisted of surface scans for beta and gamma radiation, direct measurements for total beta activity, and collection of smear samples for determining removable radioactivity levels. In addition, the confirmatory surveys confirmed that DRPs were identified and removed by ZS. The criteria (ML23167A069) for the confirmatory surveys conducted from June-August 2023 were used to determine how to proceed with the remaining FSSR and PSR reviews.

Throughout the decommissioning process, the NRC staff inspected the activities on-site to ensure that the decommissioning was conducted safely and in compliance with NRC regulations and licensee procedures. Inspections are conducted to verify site has been decontaminated to acceptable residual radioactivity levels in accordance with the approved LTP or 10 CFR Part 20, Subpart E, verify licensees procedures, measurements, surveys, and documentation comply with the LTP, and conduct sufficient surveys so the NRC has confidence in ZS results that the site does not pose an undue risk to public health and safety. NRC inspections of Zion decommissioning activities are documented in the following inspection reports:

Table 1, NRC Inspection Reports for Zion Regarding FSSs ADAMS Document Date Title Accession No. ML13319A628 November 14, 2013 Zion Nuclear Power Station Third Quarter Inspection Report 05000295 011(DNMS);05000304-13-011(DNMS)

ML14052A359 December 23, 2013 IR 05000295-13-014, 05000304-13-014; 12/23/2013; Zion Power Station Fourth Quarter, Inspection Report ML14316A214 November 10, 2014 IR 05000295/2014009(DNMS);

05000304/2014009(DNMS);

07201037/2014003(DNMS) on 09/18/14 with In-office Review through 10/16/14, Zion Nuclear Power Station, NRC Inspection Report ML16228A187 August 15, 2016 Inspection Report 05000295/2016002 (DNMS);

05000304/2016002 (DNMS); 07201037/2016001 (DNMS), Zion Nuclear Power Station ML17047A500 February 16, 2017 NRC Inspection Report No.

05000295/2016003(DNMS);

05000304/2016003(DNMS) - Zion Nuclear Power Station ML18044A577 February 13, 2018 NRC Inspection Report No.

05000295/2017002(DNMS);

05000304/2017002(DNMS) - Zion Nuclear Power Station ML18271A122 September 28, 2018 NRC Inspection Report No.

05000295/2018001(DNMS);

05000304/2018001(DNMS); And 07201037/2018001(DNMS) Zion Nuclear Power Station 8

ADAMS Document Date Title Accession No. ML19058A248 February 27, 2019 NRC Inspection Report No.

05000295/2018002(DNMS);

05000304/2018002(DNMS) Zion Nuclear Power Station ML20080J249 March 18, 2020 IR 05000295/2019001(DNMS);

05000304/2019001(DNMS) Zion Nuclear Power Station ML21021A093 January 21, 2021 NRC Inspection Report No.

05000295/2020001(DNMS);

05000304/2020001(DNMS); And 07201037/2020001(DNMS) - Zion Nuclear Power Station ML23024A208 January 27, 2023 Zion Nuclear Power Station, NRC Inspection Report 05000295/2022001 (DRSS); 05000304/2022001 (DRSS)

ML23305A145 November 2, 2023 NRC Inspection Report No.

05000295/2023001(DRSS);

05000304/2023001(DRSS)-Zion Nuclear Power Station The NRC staffs review and conclusion that all the FSSRs are acceptable is documented in correspondence with ZS (ML23310A311 Pkg) and the SER that is referred in Table 2, FSSRs and Corresponding NRC FSSR Acceptability Table 2, FSSRs and Corresponding NRC FSSR Acceptability Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 10205 Switchyard 1 1 ML19178A098 ML23310A312 10219A Area Far South of 1 1 ML19178A100 Switchyard 10219B Area Far South of 1 1 ML19178A101 Switchyard 10220C Adjacent of South 1 1 ML19178A102 Restricted Area-Lakeshore 10222 North Beach Area 1 1 ML19178A103 10223 Power Block Beach Area 1 2 ML20073F667 10224 South Beach Area 1 1 ML19178A105 10301 West Training Area 1 1 ML19178A107 9

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 01100/01110 Unit 1 Containment 2, 1 ML20167A285 ML23310A312 Basement Survey Units Part 1 01111 Containment In-Core Sump 2, 1 ML21067A219 Discharge Pipe Part 1 01112/02112/05120 Penetrations 2, 1 ML21067A214 Part 1 02100/02110 Containment 2, 1 ML20167A287 Basement Survey Units Part 1 03202 Spent Fuel Pool/Transfer 2, 1 ML19295G826 Canal Basement survey Part 1 05100 Auxiliary Bld. Basement 2, 1 ML20167A288 Part 1 05119 Auxiliary Bld. 542 Foot Elev. 2, 1 ML19295G828 Embedded Floor Drain Pipe Part 1 06100 Turbine Bld. Basement 2, 2 ML21067A218 Part 1 06105B Turbine Bld. 560 Foot Elev. 2, 0 ML19295G837 Embedded Floor Drain Pipe Part 1 06107 Unit 1Tendon Buttress Pits 2, 0 ML19295G841 Part 1 06108 Unit 1Tendon Buttress Pits 2, 0 ML19295G843 Part 1 06201 Unit 1 Diesel Fuel Oil 2, 2 ML21067A202 Storage Tank Room Part 1 06202 Unit 2 Diesel Fuel Oil 2, 2 ML21067A196 Storage Tank Room Part 1 06209 Unit 1 Steam Tunnel 2, 0 ML19295G853 Embedded Floor Drain Pipe Part 1 06210 Unit 2 Stem Tunnel 2, 0 ML19295G855 Embedded Floor Drain Pipe Part 1 06211 Unit 1 Tendon Tunnel 547 2, 0 ML19295G857 Foot Embedded Floor Drain Part 1 Pipe 06212 Unit 2 Tendon Tunnel 547 2, 0 ML19295G859 Foot Embedded Floor Drain Part 1 Pipe 06213/06214 Unit 1 East & West 2, 2 ML21067A216 Steam Tunnel Valve Houses Part 1 06215/06216 Unit 2 East & West 2, 0 ML19295G866 Steam Tunnel Valve Houses Part 1 10

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 08100 Crib House/Forebay 2, 2 ML21067A211 Basement Part 1 09100 WWTF 2, 0 ML19295G873 Part 1 00101A Condensate Feed Water 2, 1 ML20167A283 Supply and Recirculation Part 2 Buried Pipe No. T-103, T-105, and T-106 00101B Primary Water Supply 2, 1 ML20167A284 Header T-095 and T-102 Part 2 Buried Pipe 00101F Diesel Generator Heat 2, 0 ML19338B785 Exchangers Service Water Part 2 Supply and Service Water Return Buried Pipe 00101H Service Water Supply 2, 0 ML19338B790 Header CO-26 and CO-29 Part 2 Buried Pipe 00150A/B/C North Yard Storm Drain 2, 0 ML19338B788 Buried Piping Part 2 10201A Northeast (NE) Corner of 3 0 ML20009E586 ML23310A312 Restricted Area - Lakeshore 10201B NE Corner of Restricted 3 0 ML20009E577 Area- Lakeshore 10201C NE Corner of Restricted 3 1 ML22237A207 Area- Lakeshore 10201D NE Corner of Restricted 3 1 ML22237A208 Area- Lakeshore 10202A Interim Radioactive Waste 3 0 ML20009E606 Storage Facility (IRSF)/Fire Training Area 10202B IRSF/Fire Training Area 3 0 ML20009E619 10202C IRSF/Fire Training Area 3 1 ML22237A209 10202D IRSF/Fire Training Area 3 1 ML22237A210 10203D East Training Area 3 0 ML20009E610 10203E East Training Area 3 0 ML20009E578 10209A Restricted Area South of 3 0 ML20009E617 Gate House 10209B Restricted Area South of 3 0 ML20009E564 Gate House 11

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 10209D Restricted Area South of 3 1 ML20147A088 Gate House 10209E Restricted Area South of 3 0 ML20009E623 Gate House 10210A Restricted Area South of 3 0 ML20009E594 Turbine Building 10210B Restricted Area South of 3 0 ML20009E592 Turbine Building 10210C Restricted Area South of 3 0 ML20009E584 Turbine Building 10211A Southeast Corner of 3 0 ML20009E605 Restricted Area - Lakeshore 10211B Southeast Corner of 3 0 ML20009E560 Restricted Area - Lakeshore 10220B Southeast Corner of 3 0 ML20009E622 Exclusion Area - Inland 10220D Southeast Corner of 3 0 ML20009E561 Exclusion Area - Inland 10220E Southeast Corner of 3 0 ML20009E621 Exclusion Area - Inland 10220F Southeast Corner of 3 0 ML20009E570 Exclusion Area - Inland 10220G Southeast Corner of 3 0 ML20009E563 Exclusion Area - Inland 10220J Southeast Corner of 3 1 ML20147A089 Exclusion Area - Inland 10221B South of Protected Area - 3 1 ML21067A185 Lakeshore 10221E South of Protected Area - 3 0 ML20009E612 Lakeshore 10221F South of Protected Area - 3 0 ML20009E573 Lakeshore 10221G South of Protected Area - 3 0 ML20009E581 Lakeshore 10221H South of Protected Area - 3 0 ML20009E566 Lakeshore 12101 WWTF Sludge Drying Bed 3 1 ML20147A090 12102 WWTF 3 1 ML22279A987 12103 Unit 2 Primary Water Storage 3 1 ML22279A988 Tanks (PWST)/SST Area 12112 Unit 1, PWST/SST Area East 3 1 ML22237A211 12

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 12113 Unit 1, PWST/SST Area 3 1 ML22224A004 West 12203B Area Under Service 3 1 ML22224A006 Building and Southeast Yard 12203C Area Under Service 3 1 ML22224A007 Building and Southeast Yard 12203D Area Under Service 3 1 ML22224A008 Building and Southeast Yard 12204A Crib House Area 3 0 ML20009E618 12204B Crib House Area 3 1 ML20147A091 12204C Exposed Wood Timber, 3 0 ML21067A210 Piping and Large Boulder 10203A East Training Area 4 1 ML20133J978 ML23310A312 10203B East Training Area 4 1 ML20133J980 10203C East Training Area 4 1 ML20133J981 10203F East Training Area 4 1 ML20133J982 10204A North Gate Area 4 1 ML20133J983 10204B North Gate Area 4 1 ML20133J984 10204C North Gate Area 4 1 ML20133J985 10204D North Gate Area 4 1 ML20133J986 10206A Station Construction Area 4 1 ML20133J987 10206B Station Construction Area 4 1 ML20133J988 10206C Station Construction Area 4 1 ML20133J989 10206D Station Construction Area 4 1 ML20133J990 10206E Station Construction Area 4 1 ML20133J991 10207A North Warehouse Area 4 1 ML20133J992 10207B North Warehouse Area 4 1 ML20133J993 10207C North Warehouse Area 4 1 ML20133J994 10207D North Warehouse Area 4 1 ML20133J995 10207E North Warehouse Area 4 1 ML20133J996 10208A South Warehouse Area 4 1 ML20133J997 10208B South Warehouse Area 4 1 ML20133J998 10208C South Warehouse Area 4 1 ML20133J999 13

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 10208D South Warehouse Area 4 1 ML20133K000 10209C Restricted Area South of 4 1 ML20133K001 Gate House 10212A NE Corner of Exclusion 4 1 ML20133K002 Area - Lakeshore 10212B NE Corner of Exclusion 4 1 ML20133K003 Area - Lakeshore 10212C NE Corner of Exclusion 4 1 ML20133K004 Area - Lakeshore 10212D NE Corner of Exclusion 4 1 ML20133K005 Area - Lakeshore 10213A NE Corner of Exclusion 4 1 ML20133K006 Area 10213B NE Corner of Exclusion 4 1 ML20133K007 Area 10213C NE Corner of Exclusion 4 1 ML20133K008 Area 10214A Construction Parking Area, 4 1 ML20133K009 Figure 2.5 10214B Construction Parking Area 4 1 ML20133K010 10214C Construction Parking Area 4 1 ML20133K011 10214D Construction Parking Area 4 1 ML20133K012 10214E Construction Parking Area 4 1 ML20133K013 10214F Construction Parking Area 4 1 ML20133K014 10220A SE Corner Exclusion Area- 4 1 ML20133K015 Lakeshore 10220H SE Corner Exclusion Area- 4 1 ML20133K016 Lakeshore 10220I SE Corner Exclusion 4 1 ML20133K017 Area -Lakeshore 10221A South of Protected Area - 4 1 ML20133K018 Inland 10221C South of Protected Area- 4 1 ML20133K019 Inland 10221D South of Protected Area- 4 1 ML20133K021 Inland 12104 North Half of Unit 2 4 1 ML20133K022 Containment 12105 South Half of Unit 2 4 1 ML20133K023 Containment 14

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 12106 North Half of Fuel & Aux 4 1 ML20133K024 Blds.

12107 South Half of Fuel & Aux 4 1 ML20133K025 Blds.

12108 North Half of Unit 1 4 1 ML20133K027 Containment 12109 South Half of Unit 2 4 1 ML20133K028 Containment 12110 South Yard Area Northeast 4 1 ML20133K029 of Gate House 12111 South Yard Area Northeast 4 1 ML20133K030 of Gate House 12201A North Protected Area Yard 4 1 ML20133K031 12201B North Protected Area Yard 4 1 ML20133K032 12201C North Protected Area Yard 4 2 ML22279A989 12201D North Protected Area Yard 4 2 ML22279A990 12201E North Protected Area Yard 4 2 ML22279A991 12202A Gate House and Southwest 4 1 ML20133K036 Yard 12202B Gate House and Southwest 4 1 ML20133K037 Yard 12202C Gate House and Southwest 4 1 ML20133K038 Yard 12202D Gate House and Southwest 4 1 ML20133K039 Yard 12202E Gate House and Southwest 4 1 ML20133K040 Yard 12202F Gate House and Southwest 4 1 ML20133K041 Yard 12203A Under Service Building and 4 2 ML22224A005 Southeast Yard 12205A Area Under the Turbine 4 2 ML22237A212 Building 12205B Area Under the Turbine 4 1 ML20133K044 Building 12205C Area Under the Turbine 4 1 ML20133K045 Building 12205D Area Under the Turbine 4 1 ML20133K046 Building 15

Survey Unit Release Record FSSR Revision ZS submittal NRC FSSR and Reference to Phased ML No. Safety LTP, Revision 2 (ML18052A857) Submittal Evaluation (Table 2-4, Initial List of Open ML No.

Area Land Survey Units and Phase No.

Table 5-2, Embedded Pipe and Penetration Survey Units) 12205E Area Under the Turbine 4 1 ML20133K047 Building As described in Section 1.5.5 of the approved LTP, ZS committed to follow the FSS Plan, for completing the remaining cleanup activities. Section 5 of the LTP describes the FSS Plan that encompasses the radiological assessment of all affected structures, systems, and land areas for the purpose of quantifying the concentrations of any residual activity that exists following all decontamination activities. Table 3, List of Revisions to the FSS Final Reports, provides the title and ML number of the revisions of the FSS Final Reports that reflect rework by ZS.

Table 3, List of Revisions to FSS Final Reports Final Report Revision Accession No.

Phase 1, FSS Final Report 2 ML20073F671 Phase 2, Part 1 FSS Final Report 2 ML21067A204 Phase 2, Part 2 FSS Final Report 1 ML20167A282 Phase 3 FSS Final Report 1 ML22279A985 Phase 4 FSS Final Report 2 ML22279A986

.At the request of the NRC, ORISE conducted confirmatory survey activities at the facility for decommissioning. Reports detailing these confirmatory survey activities are listed in Table 4, Reports on Zion Regarding Confirmatory Surveys for Decommissioning.

Table 4, Reports on Zion Regarding Confirmatory Surveys for Decommissioning ADAMS Document Date Title Accession No. ML15245A525 August 31, 2015 Final Report - Independent Confirmatory Survey Summary and Results for the Crib House and Non-Impacted Open Land Areas at the Zion Nuclear Power Station, Zion, Illinois (RFTA No.15-005); DCN 5271-SR-01-0 ML16053A304 December 23, 2015 Revised Final Report - Independent Confirmatory Survey Summary and Results for the Crib House and Non-Impacted Open Land Areas at the Zion Nuclear Power Station, Zion, Illinois (RFTA No.15-005); DCN 5271-SR-01-1 ML18240A035 August 5, 2016 Report dated August 5, 2016, from Kaitlin M.

Engel, Oak Ridge Associated Universities (ORAU), to John Hickman, U.S. NRC, regarding Independent Confirmatory Survey of the Turbine Building Basement and Open Land Areas at the Zion Nuclear Power Station 16

ADAMS Document Date Title Accession No. ML18285A143 October 9, 2018 Independent Confirmatory Survey Summary and Results for the Containment and Auxiliary Buildings at the Zion Nuclear Power Station, Zion, Illinois ML19053A677 February 7, 2019 Oak Ridge Institute for Science & Education -

Submittal of Independent Confirmatory Survey Summary and Results for the Waste Water Treatment Facility and Select Land Areas at the Zion Nuclear Power Station ML20027A238 January 24, 2020 Independent Confirmatory Survey Summary and Results for The Spent Fuel Pool and Transfer Canal at The Zion Nuclear Power Station, Zion, Illinois ML20029D896 January 28, 2020 Independent Confirmatory Survey Summary and Results for Select Penetrations and Embedded Piping in the Containment and Auxiliary Buildings at the Zion Nuclear Power Station ML20034D661 January 31, 2020 Oak Ridge Institute for Science & Education -

Transmittal of Independent Confirmatory Survey Summary and Results for the Subsurface Soils Associated With the Sacrificial Barrier at the Zion Nuclear Power Station ML20127H834 April 24, 2020 Independent Confirmatory Survey Summary and Results of The Remaining Land Areas at the Zion Nuclear Power Station, Zion, Illinois ML21267A523 September 2, 2021 ORISE Report of April 2021 Survey at Zion Nuclear Power Station ML23310A108 November 3, 2023 Zion Nuclear Generating Station, Units 1 and 2

- Confirmatory Survey Report 2023 Under 10 CFR 50.82(a)(11) the NRC terminates the relevant license when it determines: (1) dismantlement has been performed in accordance with the approved LTP; and (2) the final radiation survey and associated documentation, including an assessment of dose contributions associated with areas released for use before approval of the LTP, demonstrate that the facility and site have met the criteria for decommissioning in 10 CFR Part 20, Subpart E. Under 10 CFR 20.1402, found in Subpart E, a site will be considered acceptable for unrestricted use if: (1) the residual radioactivity that is distinguishable from background radiation results in a total effective dose equivalent (TEDE) to an average member of the critical group that does not exceed 25 mrem per year; and (2) the residual radioactivity has been reduced to levels that are as-low-as-reasonably achievable (ALARA). The NRC staff used the approach discussed under, "For PSR (partial site release) and previous PSR interactions" in Appendix K, Section K.1.5, in the NUREG-1757, Vol 2, Rev.2, Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria (ML22194A859) to conduct its review.

As noted above, the NRC staff has previously found acceptable in 2016 a PSR of non-impacted areas at Zion. As discussed in Appendix K, of NUREG 1757, Vol 2, Rev. 2, when a license 17

pursues PSR, the NRC staff takes into consideration the any previous PSRs that NRC has found acceptable for the site when it considers final license termination. The entire site must meet the Subpart E dose constraint of 25 mrem/yr TEDE plus ALARA.

Dose Assessment ZS decommissioned the site using the Multi-Agency Radiation Survey and Site Investigation Manual, NUREG-1575, Rev. 1 (MARSSIM) (ML003761476 Pkg), approach, meaning ZS demonstrated compliance on a SU by SU basis. Under this method, the size of the SU and the rigor of the surveys performed are determined based on the expected level of residual radioactivity in areas across the site as well as spatial and topographical considerations. The NRC staff evaluation of the submittals listed in Table 2, FSSRs and Corresponding NRC FSSR Acceptability above, concludes that ZS calculated compliance dose summation of 18.73 mrem/y was determined correctly in a manner that is consistent with the approved LTP and NRC guidance. This dose corresponds to a conservative estimate of the hypothetical dose that future site inhabitants across all SUs would experience. This all-pathway site dose corresponds to an upper limit dose and one inhabitant (average member of the critical group) could not be present in the places of maximum dose from each media which are not co-located in one SU. The NRC staff also performed an independent evaluation of the potential dose from a hot spot (ROC) that was identified by ORISE in 2023 to risk-inform its decision on whether the site meets the unrestricted release criteria in 10 CFR 20.1402. The NRC staff estimated that the hypothetical dose from this hot spot and other residual radioactivity in the affected SUs would be in the range of 5.0 mrem/y to 14.9 mrem/y. Further, to risk-inform the release decision, the Less Likely but Plausible (LLBP) dose assessment for DRPs found exposure to a DRP would result in a dose below 20 mrem (TEDE). Estimated doses are consistent with dose ranges at or under the public dose limit. Effective dose estimations are under the unrestricted release criterion without weighting for probability of exposure occurring. Refer to Attachment A, Particle Assessment for Zion Nuclear Power Station of this SER for more details of the LLBP assessment.

Based on cleanup activities carried out by ZS for decommissioning; the NRC staffs review of ZS Decommissioning FSSRs; and the results of ORISE confirmatory surveys for decommissioning, conducted under contract with the NRC, the NRC staff concludes that ZS has met the criteria of 10 CFR 20.1402 for decommissioning activities.

The NRC considered the final dose from for the entire site, except the ISFSI, ISFSI Support Building and the ISFSI Warehouse which will remain under License Nos. DPR-39 and DPR-48. In this case, the site is defined as the entire site, including the portion released under PSR that occurred in 2016 and the remainder of the site addressed under the recent PSR request (June 2020, as supplemented on March 3, 2021) and does not include the ISFSI. No conditions were identified in the licenses related to PSR. In the NRC staffs evaluation of the FSSs (See Table 2, FSSRs and Corresponding NRC FSSR Acceptability, above), the NRC staff concluded applying the sum of the fraction approach, described in detail in NUREG-1757, Vol 2, Rev. 2 (ML22194A859), the actual cleanup values demonstrated that the potential dose from all residual radioactivity at the site from all media is less than 25 mrem/y TEDE plus ALARA.

Therefore, based on the above discussion, the NRC staff concludes that the entire Zion site, excluding the ISFSI, meets the requirements of 10 CFR 20.1402, and is considered acceptable for unrestricted use because the residual radioactivity that is distinguishable from the background radiation results in a total TEDE to an average member of the critical group that does not exceed 18

25 mrem/y, and the residual radioactivity has been reduced to levels that are ALARA.

Other Documents Required for License Termination In addition to the PSR requirements of 10 CFR Part 50, 10 CFR Part 30, Rules of General Applicability to Domestic Licensing of Byproduct Material, 10 CFR 40 Domestic Licensing of Source Material, and 10 CFR Part 70, Domestic Licensing of Special Nuclear Material, also have requirements for forwarding of specific records to NRC prior to PSR. Table 5, Record Forwarding Requirements, summarizes these requirements.

Table 5, Record Forwarding Requirements Requirement Description 10 CFR 30.51(d) Prior to license termination, each licensee authorized to possess radioactive material with a half-life greater than 120 days, in an unsealed form, shall forward the following records to the appropriate NRC Regional Office:

(1) Records of disposal of licensed material made under 10 CFR 20.2002 (including burials authorized before January 28, 1981),

20.2003, 20.2004, 20.2005; and (2) Records required by 10 CFR 20.2103(b)(4).

10 CFR 30.51(f) Prior to license termination, each licensee shall forward the records required by 10 CFR 30.35(g) to the appropriate NRC Regional Office.

10 CFR 40.61(d) Prior to license termination, each licensee authorized to possess source material, in an unsealed form, shall forward the following records to the appropriate NRC Regional Office:

(1) Records of disposal of licensed material made under 10 CFR 20.2002 (including burials authorized before January 28, 1981),

20.2003, 20.2004, 20.2005; and (2) Records required by 10 CFR 20.2103(b)(4).

10 CFR 40.61(f)

Prior to license termination, each licensee shall forward the records required by 10 CFR 40.36(f) to the appropriate NRC Regional Office.

10 CFR 70.51(a) Before license termination, licensees shall forward the following records to the appropriate NRC Regional Office:

(1) Records of disposal of licensed material made under 10 CFR 20.2002 (including burials authorized before January 28, 1981),

20.2003, 20.2004, 20.2005; and (2) Records required by 10 CFR 20.2103(b)(4); and (3) Records required by 10 CFR 70.25(g).

Regarding the record provision requirements of 10 CFR 30.51(d)(1), 10 CFR 40.61(d)(1), and 10 CFR 70.51(a)(1), ZS has not disposed of licensed material under 10 CFR 20.2002. ZS has never applied for and received NRC approval for disposal of waste in accordance with 10 CFR 20.2002.

Therefore, records of such disposals do not exist because this type of disposal were never made at the Zion site.

ZS has not disposed of any licensed material under 10 CFR 20.2003, 20.2004, or 20.2005.

19

Therefore, records of such disposals do not exist because these types of disposals were never made at the Zion site. Based on the information above and prior submittals to the NRC, the NRC considers the record forwarding requirements in 10 CFR 30.51(d)(1), 10 CFR 40.61(d)(1), and 10 CFR 70.51(a)(1) to be met in support of the Zion PSR.

ZS addressed the requirements of 10 CFR 30.51(d)(2), 10 CFR 40.61(d)(2), and 10 CFR 70.51(a)(2), which require submittal of records required by 10 CFR 20.2103(b)(4), collectively because the requirements are identical. Paragraph 20.2103(b)(4) addresses records associated with the release of radioactive effluents to the environment.

Also, as required by 10 CFR 50.36 a(a)(2), the Zion Technical Specifications, and the Zion Quality Assurance Plan, ZS has submitted an Annual Radioactive Effluent Release Report (ARERR) to the NRC on an annual basis. The ARERR provides a summary of gaseous and liquid radioactive effluents released from Zion to the environment during the period of January 1 through December 31 for a given calendar year. The ARERR also provides the results of measurements and calculations used to evaluate the radiation dose for a hypothetical individual at or beyond the applicable site boundary.

In accordance with Facility Operation License Nos. DPR-39 and DPR-48, Quality Assurance Project Plan, Appendix B, Section 5.7.3, Radioactive Effluent Release Report, for the Zion site, ZS must submit an ARERR. The report is required to be submitted prior to May 1 of the following year, reporting the on the previous year reporting period (i.e., between January and December of the year before). Also, the Certificate of Compliance No. 1031 for the MAGNASTOR SYSTEM, Appendix A, Technical Specification 5.1, requires submittal of an Annual Radioactive Effluent Control Program report which has been historically included in the ARERR. Per the Off-site Dose Calculation Manual (ODCM), Section 12.7.3.1c), changes made to the ODCM shall be submitted, as a complete copy, with the ARERR for the reporting period in which any changes to the ODCM were made effective. There were no changes made to the during the 2022 reporting period. ZS states in its April 23, 2023, ARERR submittal (ML23117A369) for calendar year 2022, that there were no radioactive shipments and no gaseous or liquid effluent releases, however ZS states that low-level waste was removed from the site grounds, packaged, loaded on trucks and shipped to EnergySolutions low-level radioactive Waste Facility in Utah as detailed in Table A-3 of the April 23, 2023, ARERR report. With all the previous ARERRs, as noted above, the NRC staff conclude that the decommissioning record associated with the release of effluents to the environment is complete for the PSR, excluding the ISFSI, ISFSI Support Building, and ISFSI Warehouse. The PSR will have no impact on the requirements to submit the ARERR.

Gaseous, liquid, and solid radioactive waste systems associated with the operation of the Zion site have been removed and disposed of. Site decommissioning activities have been concluded for the site (except those required in the future for the ISFSI), and discharges of radioactive material (gaseous or liquid) are no longer made. The ISFSI casks are leak tight under normal and various postulated accident conditions, and thus are not a source of effluent (ML21102A397). Accordingly, the ODCM has been revised to address only the ISFSI. Monitoring in accordance with the ODCM continues and will not be impacted by the proposed PSR. Therefore, the ODCM will not be affected by the release of the proposed areas.

Zion received a 'No Further Remediation Letter' from the Illinois Environmental Protection Agency on November 7, 2017 (ML19303A615). The letter verified that ZS had demonstrated that the remediation objectives were completed in accordance with the site's Remedial Action Plan, and 35 Illinois Administrative Code Part 740. The Environmental Monitoring Program for the Zion site has been revised to address monitoring associated only with the ISFSI which is to be retained under the 20

Part 50 licenses. Therefore, the Environmental Monitoring Program will not be affected by the release of the proposed areas.

With these submittals, the NRC staff conclude that ZS has met the requirements of 10 CFR 30.51(d)(2), 10 CFR 40.61(d)(2), and 10 CFR 70.51(a)(2).

Due to the similarity of the requirements, the NRC also assessed the requirements of 10 CFR 30.51(f), 10 CFR 40.61(f), and 10 CFR 70.51(a)(3), collectively. These regulations require the licensee to forward information important to decommissioning as required by paragraphs (1), (2),

(3), and (4) of 10 CFR 30.35(g), 10 CFR 40.36(f), and 10 CFR 70.25(g), respectively. ZS has met these requirements through the submittal of: (1) ZSPS LTP, revisions and information incorporated therein; (2) Zion Site Historical Site Assessments, Characterization reports, and groundwater sampling campaigns of which the results were summarized in the LTP; and (3) Zion FSSRs and (4) special surveillances.

Based on the above information, the NRC concludes that ZS has met the requirements of 10 CFR Parts 30, 40, and 70 for forwarding of specific records to NRC prior to PSR, excluding the ISFSI, ISFSI Support Building and ISFSI Warehouse.

Impact of Proposed Partial Site Release on Programs and Documents The licensing basis for Zion includes the maintenance of certain programs to fulfill regulatory requirements and functional responsibilities. Throughout decommissioning, ZS has modified these programs as necessary, including terminating certain programs when the applicable concern is no longer relevant. These changes are implemented using the change processes specified for each type of program. The methodology for releasing the remaining land from the Zion 10 CFR Part 50 licenses requires a review and assessment of the impact on these programs for the lands remaining within the domain of the Part 50 licenses. The NRC accepted this change approach during review and approval of the approved LTP.

Technical Specifications ZS attests that the Zion Defueled Technical Specifications are not impacted by the release of the subject SUs, as a size and description of the site are not included in the Technical Specifications.

The NRC staff verified that the only remaining items in the Technical Specifications are the site location, which does not include the size or description of the site, and High Radiation Area requirements, which are no longer relevant.

ZS attests that the NAC-MAGNASTOR Technical Specifications would also not be impacted by the PSR. ZS maintains an ISFSI 10 CFR 72.212 Report, Rev.10, that includes an estimated dose to the nearest real individual at the Owner CAB (also the CAB per Part 20) as shown in Figure , Zion Site Map with Dose Points, below. Section 10.3 of the ISFSI 10 CFR 72.212 Report estimates an occupancy dose at 772 feet from the ISFSI, to the nearest real individual, of 11.8 mrem/year. The individual is a hypothetical Illinois State Beach Park Worker at the nearest southern Owner CAB.

ZS combines the projected boundary dose from the ISFSI (11.8 mrem/yr) and the maximum residual plant area dose from direct exposure to soil (1.016 mrem/year 3). ZS attests that the 2F 3 In Revision 3 to Supporting Information for the Phased Release of Land from the 10 CFR Part 50 License (ML21102A397), ZS updated the value of their maximum soil dose to 1.95 mrem/y. The combined dose of 1.95 mrem/y and 11.8 mrem/y equals 13.75 mrem/y, which remains within their technical specification basis.

21

combined result (12.816 mrem/year) confirms that the Technical Specification basis will continue to be maintained after PSR has been implemented.

NRC staff note a slight inconsistency in the PSR from 2016 and the ISFSI 10 CFR 72.212 report (nonpublic) in that the PSR request states the 11.8 mrem/yr is for a long-term camper, and the 72.212 report calls this individual a park worker. Also, the NRC staff note that while the Part 20 CAB and the Part 72 CAB are clearly identified in the figure provided with the PSR request, this same figure is not part of the 10 CFR 72.212 report. Furthermore, the language about CAB in the 10 CFR 72.212 report could be clarified. For example, the 10 CFR 72.212 report states that, The ZNPS ISFSI is situated within the ZNPS controlled area such that the minimum distance from the center of the pads to the southern site boundary is approximately 772 feet (235.4 meters) and 221 feet (67.5 meters) to the ComEd (Commonwealth Edison) switchyard fence. ComEd workers and contractors are allowed into the ZNPS controlled area to access the switchyard and need key card access to enter the ComEd switchyard. In this way, the 72.212 report does not clearly distinguish between a Part 72 CAB and a Part 20 CAB as is done in the PSR. Instead, it denotes a distance to the southern site boundary.

The NRC staff requested that ZS clarify how the CAB is defined in the 72.212 report, and ZS provided the following statement (ML21131A072):

The Controlled Area Boundary as defined by 10 CFR 20 and 10 CFR 72 is synonymous with the Zion Station Owner Controlled Boundary as delineated in the Zion Station ISFSI Emergency Plan. The ISFSI and the Commonwealth Edison Electrical Switchyard are both located within this Controlled Area Boundary as described in the 10 CFR 50 Partial Site Release. The previously transmitted map demonstrating a more limited 100-meter Controlled Area as defined in 10CFR72.106(b) was theoretical in nature and only for purposes of future postulated dose assessments at that more restrictive boundary. There is no intention by ZionSolutions to reduce the Controlled Area Boundary as part of the requested 10 CFR 50 Partial Site Release.

ZS subsequently clarified the above statement by stating (ML23303A090):

The Part 20 Controlled Area Boundary (owner controlled area) is not synonymous with the Part 72 controlled area, as indicated by the map in ML21102A397.

And (what was) intended was that the Part 72 controlled boundary is within the Part 20 controlled boundary, which is also described in the email.

ZS points out that the information that was submitted in ZS-2020-0011, Attachment, Zion Station Restoration Project Supporting Information for the Phased Release of Land from the 10 CFR Part 50 License, Revision 3 (ML21102A397) should be used.

NRC staff acknowledges that it is acceptable for an area to be released from the Part 50 license without restrictions and at the same time be designated a part of the controlled area (see 10 CFR 20.1003 and 10 CFR 72.3). It is possible for the same area to qualify as both unrestricted and controlled as long as the licensee can demonstrate that the site for unrestricted release meets the necessary regulatory requirements in 10 CFR 50.82(a)(11)(ii) and 20.1402; and that an individual at or beyond the CAB meets the dose criteria set out in the applicable Certificate of Compliance for the cask design in use by the licensee under Part 72 (in the event of a design basis accident),and 22

that the licensee exercises authority over the use of the controlled area (10 CFR 72.3). ZS compliance with 20.1402 for the Zion site, excluding the ISFSI, is evaluated in this safety evaluation. ZS compliance with 10 CFR Part 72 is evaluated in ongoing inspection activities throughout the duration of the ISFSI.

10 CFR Part 72 requires that the licensee demonstrate requisite authority of the controlled area.

Decisions regarding control are made on a case-by-case basis depending upon the specific details presented. ZS has attested that the PSR request does not result in any changes to the description of the controlled area, and how it or a licensee intends to maintain authority over the controlled area for the ISFSI. As seen below in Figure , Zion Site Boundaries, the southernmost portion of the switchyard is within the Part 72 ISFSI CAB that is in accordance with 10 CFR 72.106(b) while the entire switchyard is within the Part 20 CAB. ZS attests (ML21102A397) that access to the switchyard by ComEd workers is controlled and verifiable. The requirement to maintain authority over the controlled area is an operational measure that must be in place while the ISFSI operates.

ZS ability to maintain control over the defined controlled area boundaries will continue to be evaluated through NRC oversight.

Because the switchyard is within the boundary of the controlled area as defined in 10 CFR Part 20, personnel entering this area are treated as members of the public in the controlled area and therefore, a dose limit of 100 mrem/year under 10 CFR 20.1301 is applicable. There is also an easement that allows ComEd access to the microwave tower located at the south Restricted Area boundary. The dose limit of 100 mrem/year under 10 CFR 20.1301 applies to ComEd in the switchyard and the microwave tower. ZS applies an occupancy of 2,088 hour0.00102 days <br />0.0244 hours <br />1.455026e-4 weeks <br />3.3484e-5 months <br />s/year to estimate the annual dose for work in the switchyard of 37.6 mrem/year (ML21102A397). This dose is within the limit of 100 mrem/year. Furthermore, if the dose from the surface soil in the switchyard were to be added based on the 2021 and 2023 confirmatory surveys, the dose would remain under 100 mrem.

As explained by ZS (ML23271A061), as detailed in the 72.212 Report, Rev. 10,the occupancy factor of 2,088 hours0.00102 days <br />0.0244 hours <br />1.455026e-4 weeks <br />3.3484e-5 months <br /> per year, which is based on 40 hrs/wk and 52 wks/yr, is intended by ZS to represent a worst-case occupancy that could reasonably be anticipated for a major rebuild or repair in the south end of the Switchyard. In comparison, a total of 1128 hours0.0131 days <br />0.313 hours <br />0.00187 weeks <br />4.29204e-4 months <br /> were spent on average annually by all ComEd workers in the switchyard over the three years of 2013-2015. When factoring in the number of workers for individual tasks, ZS calculated that an individual worker may have worked 445 hours0.00515 days <br />0.124 hours <br />7.357804e-4 weeks <br />1.693225e-4 months <br /> throughout a year (as explained by ZS (ML23271A061) based on EH&S TSD 13-009, Member of the Public Dose From All Onsite Sources, Rev 1). The NRC staff note that the dose of 37.6 mrem/yr is calculated based on an average dose rate of 13 thermoluminescent dosimeters (TLDs) located throughout the switchyard of 18.79 µrem/hr

• 2,088 hrs/yr.

As explained by ZS (ML23271A061), as described in EH&S TSD 13-009, Rev. 1, Dose points were evaluated at the South SWYD (switchyard) fence, the North SWYD fence, the new relay house and all 10 of the oil circuit breakers (OCB). The OCBs are dispersed throughout all areas of the SWYD (switchyard) as shown in attached site map.

The hourly dose was calculated at each dose point and then all 13 dose points were averaged to develop an average hourly dose rate that applies to all areas of the SWYD. The maximum dose rate at the South Radiological Restricted Area Boundary was determined to apply to the Microwave tower that may be accessed by ComEd at any time.

As explained by ZS (ML23271A061) stated in EH&S TSD 13-009, Rev. 1, The SWYD and Microwave tower will be monitored by TLDs as part of the site Radiological Environmental Monitoring Program (REMP) and ODCM and read on a quarterly basis.

ComEd will be contacted on a quarterly basis to confirm personnel occupancy for areas.

23

ComEd personnel dose from direct radiation sources will then be calculated quarterly to ensure compliance with 10 CFR 20 requirements. An annual review will also be performed as part of the REMP and ODCM to again demonstrate compliance with 10 CFR 20.

As seen from the individual TLD readings, the rates vary considerably. SY1 TLD had the maximum dose rate of 160 µmrem/hr, which equates to an annual dose above 100 mrem/yr when assuming the occupancy factor of 2088. However, this occupancy factor is high when compared to the actual hours ComEd workers spent in the switchyard for the three years of data analyzed. An individual would need to spend over 620 hours0.00718 days <br />0.172 hours <br />0.00103 weeks <br />2.3591e-4 months <br /> at that SY1 location in the switchyard in Order to receive a dose above 100 mrem/yr which is higher than the yearly average presented of 445, which represents work done in a variety of locations in the switchyard.

Figure 1, Zion Site Map with Dose Points Figure 2, Zion Site Boundaries 24

Legend Continued for Figure 2,

• Owner CAB under Part 20 - ZS has no intention of changing the current Owner CAB based on the PSR

• The Part 50 Licensed Area - in Figure 2 is the proposed Part 50 Licensed Area upon PSR

• The Part 72 CAB identified in Figure 2 is the ISFSI CAB per 10 CFR 72.106(b)

Decommissioning Final Safety Analysis Report and Post Shutdown Decommissioning Activities Report The PSR of the Zion reactor site, outside the boundary of the on-site ISFSI, will require minor edits to Section 2 of the Decommissioning Final Safety Analysis Report (DFSAR) to describe the reduced site area resulting from the removal of the subject area from the Part 50 licenses. The licensee will be responsible to make such a revision during the next required annual Final Safety Analysis Report update.

The Post Shutdown Decommissioning Activities Report does not contain a description of the site boundaries; therefore, changes of the Post Shutdown Decommissioning Activities Report are not required by the proposed PSR.

Decommissioning Environmental Report The licensee evaluated the environmental impacts as documented in the Final Environmental Statement related to operation of Zion Nuclear Power Station Units 1 and 2 and NUREG-0586, Supplement 1, Volume 1, "Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities" during preparation of the LTP. The information contained within the approved LTP was determined to be consistent or bounded by the information in the Environmental Report and the Generic Environmental Impact Statement. The PSR process was included in the approved LTP, and this PSR is proposed consistent with the process in the approved LTP. Therefore, the Environmental Report, Environmental Impact Statement, and conclusions in Section 8 of the approved LTP concerning NUREG-0586 are not impacted by the proposed PSR.

ISFSI Emergency Plan and Security Plan As the former Zion nuclear plant units have been dismantled and decommissioned, the Emergency Plan for the site has been revised to address the ISFSI only. The ISFSI Emergency Plan (ML16211A074 Pkg) describes the location of the ISFSI, the radiologically controlled and protected areas, and the CAB. The ISFSI Emergency Plan was previously approved by NRC staff on December 20, 2016 (ML16211A103).

ZS has attested that none of these locations/areas will be affected by the proposed PSR (ML21131A072). Specifically, ZS stated:

The Controlled Area Boundary as defined by 10 CFR 20 and 10 CFR 72 is synonymous with the Zion Station Owner Controlled Boundary as delineated in the Zion Station ISFSI Emergency Plan. The ISFSI and the Commonwealth Edison Electrical Switchyard are both located within this Controlled Area Boundary as described in the 10 CFR 50 Partial Site Release. The previously transmitted map demonstrating a more limited 100-meter Controlled Area as defined in 10 CFR 72.106(b) was theoretical in nature and only for purposes of future postulated dose assessments at that more restrictive boundary. There is 25

no intention by ZionSolutions to reduce the Controlled Area Boundary as part of the requested 10 CFR 50 Partial Site Release.

Although portions of the CAB are included in the area proposed for PSR, ZS stated that control of this area will continue to be maintained. Furthermore, the licensee attested that the security plan addresses the materials stored at the ISFSI and will not be affected by the release of the proposed areas. Therefore, the Emergency Plan will not be affected by release of the proposed areas.

Off-Site Dose Calculation Manual and Environmental Monitoring Program Gaseous, liquid, and solid radioactive waste systems associated with the operation of the Zion site have been removed and disposed of. Site radiological decommissioning activities have been concluded for the site and discharges of radioactive material (gaseous or liquid) are no longer made. Radiological decommissioning of the ISFSI is required after the spent nuclear fuel and GTCC is permanently removed from the site. The ISFSI casks are leak tight under normal and various postulated accident conditions, and thus are not a source of effluent (ML21102A397).

Accordingly, the Off-Site Dose Calculation Manual (ODCM) has been revised to address only the ISFSI. Monitoring in accordance with the ODCM continues and will not be impacted by the proposed PSR. Therefore, the ODCM will not be affected by the release of the proposed areas.

The ZS received a 'No Further Remediation Letter' from the Illinois Environmental Protection Agency on November 7, 2017 (ML19303A615). The letter verified that ZS had demonstrated that the remediation objectives were completed in accordance with the site's Remedial Action Plan, and 35 Illinois Administrative Code Part 740. The Environmental Monitoring Program has been revised to address monitoring associated only with the ISFSI which is to be retained under the Part 50 licenses. Therefore, the Environmental Monitoring Program will not be affected by the release of the proposed areas.

Groundwater Monitoring Program The Groundwater Monitoring Program is intended to integrate all aspects of groundwater characterization, monitoring and remediation required to support unrestricted release of the Zion site. All monitoring and supply wells on-site have been abandoned with concurrence of the NRC (ML20139A115). The Groundwater Monitoring Program is no longer required for the purposes of the Part 50 licenses. Therefore, the proposed PSR has no impact on groundwater monitoring.

Fire Protection and Training Programs The ISFSI Fire Protection and Training Programs will not be affected by the release of the subject survey areas from the Part 50 licenses.

License Termination Plan The requested release is consistent with the information in the approved LTP regarding FSS strategy and PSR requests.

10 CFR Part 100 Siting Criteria 10 CFR Part 100, Reactor Site Criteria, addresses design and environmental aspects to be considered in siting a power reactor. Decommissioning of the Zion power reactor portion of the site 26

has been completed. Only the ISFSI, ISFSI Support Building, and ISFSI Warehouse and the ISFSI CAB will remain after this proposed PSR. Therefore, the criteria of 10 CFR Part 100 no longer apply to this site and need not be addressed.

Additional Documentation to Support the Release of the Subject Survey Units ZS stated that it will maintain the following records through license termination: (1) a map of the site identifying the facility and site as defined in the original licenses; (2) a record of the Phase 1, Phase 2-Part 1, Phase 2-Part 2, Phase 3, and Phase 4 SUs released under this proposed action; and (3) documentation of the radiological conditions of the land released under this proposed action. The licensee of these Part 50 licenses must maintain these records through termination of the Part 50 licenses.

Interaction Among Proposed Site Release, Previous Site Releases, and Remaining Licensed Site On March 31, 2016 (ML16053A257), the NRC staff found that the release of approximately 214 acres of the original 331-acre Zion site was acceptable, which were classified as radiologically non-impacted, from the Zion 10 CFR Part 50 licenses. This action was taken in response to a request dated August 27, 2015 (ML15243A029), as supplemented on January 26, 2016 (ML16028A192) in accordance with the provisions of 10 CFR 50.83, which requires written acceptance from the NRC prior to release for unrestricted use of any part of a site at a nuclear power plant before receiving approval of a LTP. These previously released areas were classified as non-impacted with release criteria of no detectable plant-related radioactivity above background. Any migration of material from the previously released areas to the proposed release area (although unlikely) would have radionuclide concentrations well below the Operational DCGLs used in the areas of the proposed release. Therefore, the previous land release will not have an adverse effect on the areas of the proposed release.

To confirm ZS radiological surveys, the NRC staff contracted ORISE to conduct confirmatory surveys of the non-impacted open land areas. ORISE conducted its radiological surveys and sampling July 6-9, 2015, and provided the final report of their survey on December 23, 2015, (ML16053A304). The survey activities included visual inspections, gamma and beta radiation surface scans, gamma and beta radiation measurements, and soil and miscellaneous sampling.

Most gamma surface scans and total surface activity measurements were not distinguishable from background. Six of the seven surface soil samples collected from the non-impacted land areas contained Cs-137 concentrations above the analytical minimum detectable concentrations but were also well below the Cs-137 release criterion; low concentrations of Cs-137 are expected in background samples. Several soil samples were analyzed for Sr-90, and all results were below the Sr-90 release criterion and the analytical minimum detectable concentrations (MDCs). These survey results confirm ZS classification of the areas as non-impacted. Based on the licensees environmental assessment of the property and the ORISE confirmatory surveys, the NRC staff concluded the property has no reasonable potential for residual radioactivity more than natural background or fallout levels.

The Zion ISFSI is located within the boundary of the existing Zion site. The CAB for an ISFSI, as defined in 10 CFR 72.3, Definitions, is the area immediately surrounding an ISFSI for which the licensee exercises authority regulating its use and within which ISFSI operations are performed.

The ISFSI CAB will encompass some of the land being proposed for release from jurisdiction of the Zion 10 CFR Part 50 licenses; however, this area will continue to be under the authority and control of the licensee until the spent fuel has been transferred permanently off-site. As previously discussed, approximately 5 acres of land around the Zion ISFSI will remain under the Zion 10 CFR 27

Part 50 licenses. ZS performed a radiological evaluation for the Zion ISFSI and surrounding area in accordance with 10 CFR 72.104, Criteria for radioactive materials in effluents and direct radiation from an ISFSI, to ensure that the associated dose requirements have been met. The proposed site release will not affect the basis for this evaluation or the NAC-MAGNASTOR Technical Specifications (TS), as a calculation performed by ZS combining the dose from the Zion ISFSI and the residual plant area dose confirms that the NAC-MAGNASTOR TS basis will continue to be maintained after the proposed site release has been implemented.

Site Release Criteria and Final Status Survey Activities ZS stated that the site release criteria for the Zion site correspond to the 10 CFR 20.1402 criteria for unrestricted use. The residual radioactivity that is distinguishable from background, must not cause the TEDE to an average member of the critical group to exceed 25 mrem/yr. The residual radioactivity must also be reduced to levels that are ALARA. The results of ZS final compliance dose for basement concrete, soil, buried pipe and existing groundwater is 18.75 mrem/yr TEDE, which meets the release criteria as established in 10 CFR 20.1402.

In addition, ZS stated that the FSSR sections which support this release conclusion demonstrate that the radiological surveys were conducted in a manner consistent with the LTP and that the SUs passed the FSS. Specifically, the FSSRs indicated that:

• each survey unit in the final reports have met the Data Quality Objectives (DQOs) of the FSS sample plans;

• all identified ROC were used for statistical testing to determine the adequacy of the survey unit for FSS;

• the sample data in each survey unit passed the Sign test;

• a Retrospective Power Curve showed that adequate power was achieved in each survey unit; and

• the allowable dose for each survey unit has been met.

The NRC staff evaluated the FSS units and documented their evaluation in a FSS Safety Evaluation (See Table, 2, FSSRs and Corresponding NRC FSSR Acceptability.). The NRC staff concludes that the entire Zion site outside the boundary of the on-site ISFSI, meets the requirements of 10 CFR 20.1402 and is acceptable for unrestricted use because the residual radioactivity that is distinguishable from the background radiation results in a total TEDE to an average member of the critical group that does not exceed 25 mrem/y, and the residual radioactivity has been reduced to levels that are ALARA.

Expiration of the Zion Facility Operation Licenses, No. DPR-38 and DPR-49 The NRC staff notes that 10 CFR 50.51, Continuation of license, provides for 10 CFR Part 50 operating licenses to continue in effect beyond their expiration dates for a facility that has permanently ceased operations. This continuation authorizes ownership and possession of the production or utilization facility until the Commission notifies the licensee in writing that the license is terminated. In accordance with this requirement, during the period of continued license effectiveness, the licensee shall (1) take actions necessary to decommission and decontaminate the facility and continue to maintain the facility, including, where applicable, the storage, control and 28

maintenance of the spent fuel, in a safe condition; and (2) conduct activities in accordance with all other restrictions applicable to the facility in accordance with the NRC regulations and the provisions of the specific 10 CFR Part 50 license for the facility.

Therefore, the original Zion Facility Operating License for Unit No. 1 was issued in April 1973 and the original Zion Facility Operating License for Unit No. 2 was issued in November 1973 and would have expired forty years later. However, these licenses remain in effect to govern the remaining portion of the 10 CFR Part 50 licensed site (approximately 5 acres surrounding the Zion ISFSI) after execution of the proposed site release and the generally licensed Zion on-site ISFSI, in accordance with the provisions of 10 CFR 50.51. However, the provisions of 10 CFR 50.82(a)(3) require that:

decommissioning will be completed within 60 years of permanent cessation of operations.

Completion of decommissioning beyond 60 years will be approved by the Commission only when necessary to protect public health and safety. Factors that will be considered by the Commission in evaluating an alternative that provides for completion of decommissioning beyond 60 years of permanent cessation of operations include unavailability of waste disposal capacity and other site-specific factors affecting the licensee's capability to carry out decommissioning, including presence of other nuclear facilities at the site. Therefore, it may become necessary for the Zion licensee to address the expiration of the 60-year period for decommissioning and termination of the Zion 10 CFR Part 50 licenses specified in 10 CFR 50.82(a)(3) if the ISFSI cannot be decommissioned and the 10 CFR Part 50 licenses fully terminated by February 13, 2058 (60 years after the permanent cessation of operations for both units of February 13, 1998 (ML15232A492). The NRC staff notes that that existing regulations provide for exemption requests to the decommissioning and license termination timeline under the provisions of 10 CFR 50.12, Specific exemptions, and that specific considerations for extending the 60-year decommissioning timeframe are captured in 10 CFR 50.82(a)(3).

COMMUNICATION WITH THE STATE This safety evaluation was prepared by the NRC staff. This approval of the PSR of the Zion Site outside the boundary of the ISFSI are not LAR reviews and therefore no consultation with the State of Illinois is required. However, on October 19, 2023, the NRC staff contacted the State of Illinois for its awareness that the NRC plans to complete review of the Zion PSR request no later than November 26, 2023 (ML23296A064) and thus has been informed of NRCs intention for PSR outside the boundary of the on-site ISFSI. In addition, the State is on the Zion Listserv for all correspondence between NRC and ZS.

ENVIRONMENTAL CONSIDERATIONS The licensee evaluated the environmental impacts as documented in the Final Environmental Statement related to operation of Zion Nuclear Power Station Units 1 and 2 and NUREG-0586, Supplement 1, Volume 1, "Generic Environmental Impact Statement on Decommissioning of Nuclear Facilities" (ML023500412 Pkg) during preparation of the LTP. The information contained within the LTP was determined to be consistent or bounded by the information in the Environmental Report and the Generic Environmental Impact Statement. The PSR process was included in the LTP, and this PSR was consistent with the process in the LTP.

Pursuant to 10 CFR 51.21, 51.32, and 51.35, an environmental assessment and finding of no significant impact was published in the Federal Register on June 29, 2018 (83 FR 30783).

Accordingly, based upon the environmental assessment, the Commission determined that issuance of this amendment approving the ZS LTP will not have a significant effect on the quality of the human environment.

29

ZS decommissioning activities since approval of the LTP did not require additional environmental assessment evaluations because ZS followed the approved LTP.

EVALUATION OF THE NEED FOR NRC/ENVIRONMENTAL PROTECTION AGENCY (EPA)

LEVEL 2 CONSULTATION The NRC and U.S. EPA entered into a Memorandum of Understanding (MOU) for Consultation and Finality on Decommissioning and Decontamination of Contaminated Sites on October 9, 2002 (ML022830208). The MOU provides that, unless an NRC-licensed site exceeds any of three trigger criteria contained in the MOU, the EPA agrees to a policy of deferral to the NRC for decision making on decommissioning, without the need for consultation.

For sites that trigger the criteria in the MOU, the NRC will consult with the EPA at two points in the decommissioning process:

• prior to NRC approval of the LTP or Decommissioning Plan, which the NRC terms Level 1 consultation; and

• following completion of the FSS, which the NRC terms Level 2 consultation.

For the Zion site, during the review of the LTP LAR, the NRC consulted with the EPA under the MOU (Level 1 consultation) because the proposed DCGLs for certain radionuclides at that time exceeded the MOU soil concentration levels for the residential land use scenario (ML16084A308). After the radiological decommissioning activities were completed by ZS, the NRC staff reviewed the residual radioactivity values in the FSSRs and compared them to the trigger values in the MOU. Based on this review, the residual radioactivity in soil and groundwater at the site do not exceed the trigger values in the MOU and, as such, Level 2 consultation with EPA in accordance with the MOU is not required.

CONCLUSION The Commission has concluded, based on the considerations discussed above, that: (i) the remaining dismantlement has been performed in accordance with the approved LTP, (ii) the FSSs and associated documentation, including an assessment of dose contributions associated with parts released for use before approval of the LTP, demonstrate that the entire site, with the exception of the ISFSI which will remain under the License Nos. DPR-39 and DPR-48, have met the criteria for decommissioning in 10 CFR Part 20, Subpart E, and (iii) ZS has met the 10 CFR Parts 30, 40, and 70, Domestic Licensing of Special Nuclear Material, requirements for forwarding of specific records to NRC prior to PSR. The NRC concludes that ZS satisfied the requirements for termination, as stated in 10 CFR 50.82(a)(11), of the Zion site outside the boundary of the ISFSI.

Principal Contributors: A. Snyder, Senior Project Manager, DUWP/RDB G. Chapman, Senior Health Physicist, CHP, DUWP/RDB K. Pinkston, Risk Analyst, PhD, DUWP/RTAB L. Caponi, Risk Analyst, DUWP/RTAB Date: November 8, 2023 30

31 Attachment A, Particle Assessment for Zion Nuclear Power Station History of DRPs at Zion During reviews of Final Status Survey (FSS) data for the Zion Nuclear Power Station, Unit No. 1 and No. 2 (ZNPS or Zion) site, and subsequent Requests for Additional Information (RAIs), the NRC staff learned that decommissioning activities performed at the Zion facility from 2012 to 2018 resulted in discrete radioactive particles (DRPs), of varying activity levels and sizes, being transported from the Unit No. 1 and Unit No. 2 Containments and the Fuel Handling Building cross-contaminating other areas on-site.

The licensee, ZionSolutions, LLC (ZS), partially attributes the generation of DRPs during decommissioning activities primarily to its practices during segmenting of reactor internals underwater using a variety of cutting tools. According to the ZS, water purification was inadequate to capture and remove DRPs generated during underwater cutting operations, which likely allowed DRPs to move in the water, become suspended on the water surface, and then migrate to surrounding areas as equipment was removed from the pool (equipment removed from the water was not washed completely). ZS found multiple particles on equipment and building surfaces in the containment buildings and noted in an RAI response that the spread of DRPs was an ongoing issue throughout the reactor internals segmentation project, which ended in 2016 (Agencywide Document Access and Management System (ADAMS) Accession No. ML21103A229).

In 2014, ZS identified and removed DRPs in outdoor areas after a spread of contamination occurrence. Liners loaded with reactor internals segments were temporarily stored in a shielded array, then loaded into an overpack outside, and transported across the Zion site. Over 100 DRPs with activities ranging from 0.001 µCi to 3 µCi were identified and remediated after this occurrence in 2014. During 2014, radiological surveys identified seven more DRPs with a maximum activity of approximately seven nanocuries.

In 2015, approximately 100 DRPs were identified and removed within the Zion Security Restricted Area concentrating around the Unit 1 and Unit 2 Containment Buildings and the western path between the two buildings, with activities ranging from 0.002 µCi to 0.5 µCi. In 2015, ZS could not determine the cause of the spread of the DRPs within the Security Restricted Area. Later, in 2019, during generation of lessons learned for the Zion decommissioning, ZS attributed the presence of these particles to wind entrainment inside each Containment Building causing DRPs, that had been generated during reactor internal segmentation activities, to migrate out of the containment beginning as early as 2012 and continuing through as late as 2016.

From 2017 to mid-2018, approximately 15 DRPs, ranging in activity from 0.004 µCi to 0.23 µCi, were identified and removed by ZS. From mid-2018 through 2019, approximately 24 DRPs, ranging in activity from 0.5 nanocuries to 1.08 µCi were identified and removed by ZS. In 2019, ZS reperformed scan surveys at 100% areal coverage of open land areas where DRPs had previously been identified. The rescanning of these areas by ZS resulted in identification and removal of an additional 14 DRPs.

In addition to wind entrainment, ZS noted (ML21102A392) that DRPs were also likely spread throughout the site by water movement and use of heavy equipment. ZS stated that DRPs likely migrated to a drainage ditch in the northern area of the site (survey unit 10212D) by surface water movement. In 2018, flooding of a drainage ditch caused DRPs to move to other areas of the site 1

(SUs 10212, 10213, and 10214 were impacted by the flood). Two DRPs from the flooding action were identified and removed by ZS in survey unit 10214, with activities ranging from 0.02 Ci microcurie (SU 10214F) to 1.26 Ci (SU 10214D).

ZS summarized the history of DRPs at the Zion Site in the Zion Nuclear Power Station, Units 1 and 2 - Final Status Survey Due Diligence Plan, (ML21203A040) up through July 16, 2021. ZS states in this document that:

• Approximately 290 DRPs were identified during the course of the Zion Station Restoration Project (ZSRP).

• The number of DRPs detected during active decommissioning is approximately 255.

• Twenty-five DRPs were detected during radiological assessments (RA) or FSS.

• The number of DRPs detected by ORISE during independent verification surveys performed prior to 2021 is 5.

As summarized in the Section 3.3 of the Phase 4 FSS Final Report, Revision 2 (ML22279A986), ZS indicates that the surface soil surrounding the containment domes was contaminated by decommissioning activities:

During building demolition in the Spring of 2017, discrete particles of radioactive material were identified during the performance of operational surveys and Radiological Assessments (RA) in and around the Class 2 and Class 3 survey units. As a conservative measure starting in July of 2016, the classification of a majority of the open land survey units located within the 87-acre, fence-enclosed area was increased to Class 1.

ZS describes its choice to place a layer of clean sacrificial soil over the contaminated soil so the containment domes could be demolished without having to first remediate the soil. ZS states (ML22279A986):

In August of 2018, ZSRP [ZionSolutions Restoration Project] completed the demolition and backfill of the Auxiliary Building basement and Spent Fuel Pool (SFP). The next buildings that were slated for demolition were the Unit 1 and Unit 2 Containment domes. It was the intention of ZSRP at the time to designate the exterior concrete of the Unit 1 and Unit 2 Containment domes as CCDD (clean construction and demolition debris) and to use the CCDD as fill material in basements. However, for the concrete to be considered for use as CCDD, it was important to maintain its unrestricted release pedigree. The 588-foot grade surface soils surrounding the two Containments were identified as contaminated. While it was necessary to remediate the soils surrounding the Containments, the timeframe required was prohibitive at the time. Therefore, in lieu of remediating the exposed soil, a sacrificial layer of clean soil from off-site was placed over the contaminated indigenous surface soil with up to 1 1/2 feet of clean fill. Once the sacrificial layer was in place, the containment dome structures were demolished without having to wait for the remediation to be completed.

Following demolition of the containment buildings, ZS removed the sacrificial soil layer and contaminated layer of soil was scanned under an RA survey. ZS states (ML22279A986):

From August 2018 through December 2018, both Unit 1 and Unit 2 Containments were demolished and the resultant CCDD was removed from the area. After removal of the CCDD, the sacrificial soil was removed, and the exposed 588-foot indigenous soils were 2

scanned. The survey was performed under an RA, which required 100% scan of the soils exposed by the removal of the sacrificial layer with an alarm set-point set at the [Minimum Detectable Count Rate] MDCR of the instrument plus background. Any indication of elevated activity greater than the MDCR would then prompt investigation and remediation as necessary.

In April 2021, the NRC staff requested Oak Ridge Institute for Science and Education (ORISE),

NRCs independent contractor, to perform a presence/absence survey of select portions of open land areas on the Zion site where ZS had completed FSSs, to confirm the absence of DRPs. Eight (8) DRPs were identified and removed in the relatively small portion of the Zion site subject to this survey. The NRC staff notes that, before the April 2021 confirmatory survey, ZS had not incorporated DQOs addressing DRPs when developing its surveying techniques and, while ZS had made attempts to control the particle cross contamination, it had not fully controlled the spreading of particles. At that point, the NRC staff was uncertain as to whether the situation was fully understood with respect to the potential impact to the public, and therefore, it was premature to complete the PSR review.

After the NRC 2021 Confirmatory Survey, ZS performed a scan of the majority of the secured portion of the site during 2021-2022 using an auto scanning technique (towed array) to identify areas of likely DRP concern and subsequent hand scanning of those areas to identify and remove DRPs. This effort identified and collected three DRPs across the entire site. ZS also reperformed the FSS in select SUs using hand scanning techniques suitable for identifying DRPs and performed RAs using scanning methods appropriate for identification of DRPs in areas needing additional remediation or waste hauling paths. This identified and removed additional DRPs. Nonetheless, NRC staff did not have reasonable assurance that the towed array scanning was a sufficiently sensitive method to routinely identify DRPs; that ZS had made sufficient effort to understand and resolve the scanning sensitivity questions; and that ZS had demonstrated the extent of DRP cross contamination was identified and remediated.

The NRC documented its questions regarding ZS scanning method for DRPs using the towed array method in an interim audit report (ML22313A053).

Further, the NRC concluded (ML22313A053) that:

The licensee has addressed some, but not all, of the potential exposure concerns for public exposure to DRPs after license termination and staff have a better understanding of the licensees dose assessment after completion of this audit phase. The NRC staff has communicated the need to understand what residual materials may reasonably be left on the site and the associated potential dose/risk in order to make a regulatory decision as to the sites acceptability for license termination.

And The staff further noted, based on the licensees field performance test of the towed array methodology (ML22111A184), that the towed array scanning generally appears less sensitive than hand scanning for identifying DRPs, but that no direct comparison of the two methods has been performed. The licensee should consider providing hand scanning minimum detectable activity (MDA) to facilitate staff evaluation of the DRP investigations.

3

On October 17, 2022, ZS stated (ML22293A644 Pkg) it had completed its FSSs. On May 4, 2023, ZS stated that all known DRPs had been removed from the site and it had provided reasonable assurance that the Zion site meets the regulatory requirements for unrestricted release (ML23167A069). Subsequently, the NRC staff tasked ORISE to return to the Zion site to perform a comprehensive scan survey (confirmatory survey) of that portion of the site which had previously been scanned using the towed array and encompassing all areas where DRPs had been found to date. These DRP confirmatory surveys covered a majority of the site which is atypical. The NRC decided that this approach was needed due to: ZS positions that all known DRPs had been removed; that ZS had completed all FSSs, and; NRCs lingering concerns regarding scanning techniques utilized prior to 2021. The NRC staff developed risk-informed confirmatory survey criteria (ML23221A243) that were applied to determine the next steps needed to make a reasonable assurance determination that DRPs had been adequately addressed at the site. The confirmatory surveys (hand scanning of a majority of the site for the identification of DRPs and subsurface sampling and scanning) were also intended to enable NRC staff to make a reasonable assurance determination that encountering a DRP would be a very low possibility at the site. The NRC staffs rationale was that, if any DRPs were present, the DRPs would be found using appropriate scanning techniques and, if identified, would be removed and analyzed.

The NRC shared the 2023 Confirmatory Survey criteria with ZS before implementation to identify any unintended consequences or information the NRC staff might have overlooked prior to implementation (ML23180A145). ORISE was also to verify, by taking judgmental and random samples, the general status of residual radioactivity in soil in those SUs which had been subjected to FSSs since the previous ORISE visit in 2021.

For three weeks in the summer of 2023, ORISE scanned surface soil and did presence/absence surveys of subsurface soil at the site (ML23310A108). ORISE identified and collected 12 DRPs in surface soil during this effort; all of which were either activated metal or activated concrete based on gamma spectroscopy results. One of the last DRPs ORISE identified was at the border of an area that was not surveyed by ORISE and had not been hand scanned by ZS. NRC staff informed ZS (ML23233A150) that an extent of condition assessment in that area was needed. ZS subsequently performed the extent of condition assessment actions (survey and analysis) and identified and collected one additional DRP in the area. ZS analyzed that DRP and provided the extent of condition results (ML23251A071) to the NRC staff. The NRC evaluated the DRP and determined that it was bounded by the NRCs DRP dose assessment discussed below.

Collectively, ZS, through its remedial actions and FSSs and, ORISE, through its confirmatory surveys, removed all DRPs that were identified during site surveys, and no known DRPs remain on-site.

NRC Hypothetical Dose Assessment for DRPs at ZNPS Although remedial actions to remove DRPs have taken place, the NRC performed an assessment of the DRPs collected during 2023 to evaluate the dose should all DRPs not have been identified and removed due to human error during scanning or other circumstances. The NRC staff assumed that the most recently collected DRPs would be representative for this scenario. While a previous confirmatory survey effort in 2021 did identify a spent fuel particle in the environment, it appears that was the only time such a particle was identified during all previous surveys of the Zion site environment. The NRC staff believe that the one anomalous particle is not reflective of the most 4

plausible scenario of hypothetical exposure to a DRP, so the NRC staff has not given further consideration to that as a possibility.

The NRC considered a hypothetical encounter with a DRP at the site after the PSR to be the Less Likely but Plausible Scenario as described in NUREG-1757, Vol 2, Rev. 2 Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria (ML22194A859), Table 5.1, Comparison and Description of Scenario Terms Used in this Guidance. The LLBP scenario dose evaluations are not analyzed for compliance but rather to risk-inform the decision. For the LLBP scenario type, the NRC guidance states that land use scenarios that are plausible, based on historical uses, but are not likely within the next 100 years, considering trends and area land use plans (e.g., rural use of property currently in an urban setting) are considered. These scenarios are usually site-specific. For the ZNPS site, the LLBP site-specific scenario used to evaluate exposure to DRPs is the construction worker scenario because additional industrial or commercial development at the site is plausible once the site is released for unrestricted use and the NRC staff believe that would pose the highest probability for exposure to a DRP, in the very unlikely event it was present, due to soil movement associated with construction.

The NRC staff believe it is very unlikely that a DRP would be present at any time because of the extensive DRP hand scanning using the appropriate techniques that was conducted by ZS after 2019 and the NRC through its confirmatory surveys.

Twelve DRPs were identified during the 2023 ORISE confirmatory surveys and 1 DRP was identified during the ZS extent of condition survey. All 13 DRPs were either activated metal (primarily Co-60 activity) or activated concrete (primarily Eu-152/Eu-154 activity). The ten activated metal particles ranged in Co-60 activity from approximately 0.014 Ci to 0.38 Ci. The NRC staff notes that significant Ni-63 may also be present in these particles at slightly greater activity levels than the Co-60 but because Ni-63 is a very low energy beta-emitter and contained in what is considered an environmentally insoluble matrix, Ni-63 would not contribute in any significant way to potential dose. The three activated concrete samples ranged in Co-60 activity from 5.7E-4 Ci to 3.0E-3 Ci. The Eu-152/Eu-154 activities in these particles ranged from 4.6E-3 Ci/2.9E-4 Ci to 6.1E-2 Ci/4.4E-3 Ci.

To assess the impact of the recovered DRPs, the NRC staff initially had to consider the sizes of the DRPs collected. The NRC staff assessed the size of the DRPs by assuming the materials were the most concentrated of these material types identified during the site characterization efforts as discussed in ZS response to RAI 10 (ML22069A328) regarding FSS and PSR request reviews as related to size of DRPs (ML21238A067). For the activated metal, the concentration was based on reactor internal component characterization of the Unit 1 baffle plates with a Co-60 concentration of 4.06E+4 Ci/cm3. For activated concrete, the highest Co-60 concentration was in core B102110-CJFCCV-001 at 1.09E+3 pCi/g with an estimated concrete density of 2.35 g/cm3. Using these concentrations and the Co-60 activity estimates of the DRPs, the activated metal DRPs were estimated to range in size from 87 m to 262 m equivalent spherical diameter and from 202 m to 605 m aerodynamic equivalent diameter while the concrete DRPs range from 0.22 cm3 to 1.2 cm3 in volume. Examples of such calculations are shown below.

60 (3 ) =

60 Where is the density of the material when the maximum concentration is in units of pCi/g. For concrete this is assumed to be 2.35 g/cm3. For the smallest amount of Co-60, therefore the smallest concrete particle, the calculation was as follows:

5

570 (3 ) = = 0.223 3 1,090 2.35 /3 For the metal particles, the equivalent spherical diameter was calculated by 1st calculating the radius of a sphere of equivalent volume:

4 (3 ) = 3 3

3 3

= (3 )

4 And the diameter of the sphere is simply twice the radius.

An additional step was then needed to determine the aerodynamic equivalent diameter of the smaller particles because particles of less than 100 m aerodynamic equivalent diameter are most likely to fall out of air and not be inhaled. This was accomplished by converting the spherical equivalent diameter to an aerodynamic equivalent diameter as described by International Commission on Radiological Protection (ICRP) 66 (ICRP, 1994, #Equation D.5).

=

Where: dae is the aerodynamic equivalent diameter de is the spherical equivalent diameter is the density of the material (8 g/cm3 is assumed for steel) is the particle shape factor (for typical densities a particle shape factor of 1.5 suffices for compact, irregularly shaped particles) (ICRP 66, Sec. D.13.1)

For the smallest amount of Co-60 in the activated metal particles, the calculations would be as follows:

1.42 2

= = 3.5 7 3 4.064 3

3 3

= 2 = 2 3.5 7(3 ) = 0.0087 = 87 4

8

= 87 = 201 1.5 If any of the 13 DRPs that were removed, were hypothetically to become resuspended due to construction work, the size of the DRPs, being greater than 100 m aerodynamic equivalent 6

diameter, would generally preclude any of the particles being inadvertently introduced to an individuals respiratory tract. 4 Also, the activated concrete particles were large enough in size that 3F the NRC staff assumed those particles were precluded from being inadvertently ingested. For reference, a grain of table salt is commonly estimated to be 300 m along any side (equating to approximately 2.7E-5 cm3) and the activated metal DRPs were all less than 300 m in spherical diameter. A cubic centimeter is often compared to the volume of a pea or pencil eraser and the smallest concrete particle was estimated as being 0.22 cm3 in volume which staff consider large enough to not be inadvertently swallowed.

Because of the size of the 13 DRPs found and removed at Zion, the NRC staff considered potential exposure scenarios for the activated metal DRPs as being either potentially ingested or stuck on skin for approximately 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br /> until being washed off consistent with the 12-hour time to first shower concept described by the Defense Threat Reduction Agency (DTRA, 2010). The activated concrete particles (which were the size of small pebbles) were assessed as being in contact with skin for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> which the NRC staff considered conservative for a hypothetical scenario of a worker lying on the ground, possibly napping during a long lunch. Using dose coefficients (ML23136A178), the NRC staff determined hypothetical dose estimates for the highest activity DRPs for each media as shown below.

4 Dose Coefficients for Discrete Radioactive Particles, Hamby et.al., ADAMS Accession No. ML23136A178, page 5: Particles greater than about 100 um (in diameter) are generally assumed to fall out of the air quickly and are too large to be inhaled (worksafe.qld.gov.au).

7

Table A, Bounding Hypothetical Dose from Exposure to Most Activated DRPs Most Activated Metal DRP Hypothetical Dose Category Calculated Public Dose (Assumptions) Dose Limit (TEDE)*

Effective Dose Equivalent (EDE) 9.9 mrem 100 mrem/y (located on upper torso for 12 hours1.388889e-4 days <br />0.00333 hours <br />1.984127e-5 weeks <br />4.566e-6 months <br />)

Committed Effective Dose 2.6 mrem 100 mrem/y Equivalent (CEDE) (assuming ingested)

Most Activated Concrete DRP EDE (in contact with skin on upper 6.3 mrem 100 mrem/y torso for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br />)

• TEDE is the sum of EDE and CEDE exposures when both an internal and external dose occur Where: EDE is the effective dose equivalent from external exposure assuming a DRP is in contact with an individuals upper torso. It is a component of the TEDE dose which has a public dose limit of 100 mrem/y.

CEDE is the committed effective dose equivalent from internal exposure assuming a particle is ingested and passes through the Gastrointestinal (GI) tract consistent with reference man models (note: particles were considered to be insoluble). CEDE is a component of TEDE which has a public dose limit of 100 mrem/y.

To assist with a risk-informed consideration of DRP exposures, the NRC staff further assessed additional hypothetical exposures that are not generally considered as being applicable to meeting the unrestricted release decommissioning criteria. Specifically, the NRC staff calculated a hypothetical shallow dose equivalent exposure (SDE, or skin dose) which is a defined dose term with limits established for occupational workers. The NRC staff also assessed a hypothetical localized dose equivalent (LDE) exposure which is a previously undefined dose term that is essentially equivalent to SDE but has recently been used to assess dose within the gastrointestinal (GI) tract for potential deterministic effects (e.g., ulceration). For the most activated metal particle, the calculated SDE for a 12-hr exposure and 10 cm2 averaging area (consistent with guidance for assessing occupational exposure to hot particles) is 374 mrem. For the most activated concrete particle, which is assumed to be in contact with skin for 2 hours2.314815e-5 days <br />5.555556e-4 hours <br />3.306878e-6 weeks <br />7.61e-7 months <br /> and assuming a 10 cm2 averaging area, the calculated SDE exposure is 15 mrem. For comparison, the occupational dose limit for SDE is 50,000 mrem (see 10 CFR 20.1201(a)(2)(ii)). The NRC staff notes that the occupational dose limit was established to be protective of deterministic effects which would be the same for 8

occupational workers as for the public. Similarly, the hypothetical LDE was estimated for the highest activity metal particle assuming a 24-hour exposure and 1 cm2 averaging area in the lower large intestine/colon and was calculated to be 1,600 mrem. There is no regulatory limit for this term; however, NRC staff considers it appropriate to compare it to the ulceration threshold of ~25 Gray

(~2,500,000 mrem (see ML23136A207)). It is apparent that the hypothetical SDE/LDE exposures are more than an order of magnitude below the deterministic effect thresholds of consideration.

Another consideration the NRC staff evaluated was the possibility that activity associated with a particle of aerodynamic equivalent diameter of 100 m might potentially result in significant dose.

Particles of this size are hypothesized as being capable of being inspired and temporarily reside in the nasal cavity for a period that generally results in a higher dose than other means of exposure.

The NRC staff determined that an activated metal particle with Co-60 activity of 1.75E-03 Ci correlates to a 100 m aerodynamic diameter based on the maximum concentrations reported at the ZNPS. When the NRC staff then determined a hypothetical dose from this activity, the largest hypothetical dose estimate was found to be approximately 9.2 mrem EDE, assuming a particle is stuck in the nasal cavity for 1 day then cleared through the GI tract. The NRC staff did not perform a similar calculation for activated concrete particles because, even when using the maximum activity concentrations in concrete, the activity levels in a particle of 100 m aerodynamic equivalent diameter were essentially insignificant (e.g., < 1 pCi Co-60 would be present).

The NRC staff further considered the sensitivity of the scanning surveys performed and the hazards of any DRPs that may not have been identified and removed during the 2023 scanning surveys.

The report Estimating Scan Minimum Detectable Activities of Discrete Radioactive Particles,(ML22304A137) authored by ORISE provides a range of likely DRP Co-60 activities that scanning consistent with ORISE methods would likely detect. Table 4.1 of the report provides a range from approximately 0.1 Ci to 0.7 Ci Co-60 depending on exactly how close to the detector path the particle is located and how deeply covered in soil. The values quoted are consistent with the conditions identified by ORISE during their survey with regards to scanning speed and depth of particles in soil. ORISE identified and removed particles with the smallest activity being 0.014 Ci Co-60 suggesting that the true sensitivity could possibly be much less than that estimtaed in the report. The highest activity DRP found by ORISE at the site was 0.38 Ci Co-60, which is slightly more than half of the upper limit of sensitivity in the report. No more than double the dose calculated for the most active metal particle would be assessed (i.e., 19.8 mrem TEDE) if such were encountered and the dose from exposure to that activity DRP would still be much less than the public dose limit (or dose thresholds for deterministic effects).

Conclusion The NRC staff assessed the particles identified and collected during the 2023 scanning surveys at the Zion site. NRC contractors and ZS used appropriate hand scanning techniques for DRPs over a majority of the site so that only DRPs that may have been missed due to human error or other extenuating circumstances may remain and the NRC staff believe the probability of encountering a DRP at the Zion site is very unlikely. Because all calculated EDE/CEDE hypothetical doses were less than 100 mrem/y TEDE (the public dose limit), and other hypothetical dose estimates (SDE and LDE) were much less than what would be considered exceedance of any deterministic threshold, the NRC staff believe that there is reasonable assurance that, in the very unlikely event that exposure to DRPs could occur at the Zion site, any exposure would be consistent with the LLBP category of hypothetical considerations consistent with guidance in NUREG-1757, Vol 2, Rev. 2 Consolidated Decommissioning Guidance, Characterization, Survey, and Determination of Radiological Criteria, Table 5.1, Comparison and Description of Scenario Terms Used in this 9

Guidance (ML22194A859).

This conclusion is combined with the fact that a significant effort has been made by the NRC and its contractors as well as ZS to identify and remove DRPs from the site, demonstrating ALARA in practice. Also, because the primary radionuclides are Co-60 and Eu-152/154, the activity and potential dose associated with any remaining DRPs, if present, will reduce over time consistent with the relatively short half-lives of these radionuclides (Co-60 half-life is 5.27 years, Eu-152 half-life is 13.5 years, and Eu-154 half-life is 8.59 years). As such, the potential dose should one encounter a DRP at the site will diminish with time.

REFERENCES DTRA (Defense Threat Reduction Agency). 2010. Radiation Doses to Skin from Dermal Contamination. DTRA-TR-09-16.

ICRP (International Commission on Radiological Protection). 1994. Annals of the ICRP, Publication

66. Human Respiratory Tract Model for Radiological Protection.

10

Attachment B, Identified Discrete Radioactive Particles and Associated Clean Up Actions The table below for further information regarding DRP documentation throughout decommissioning process specific to license termination actions.

Table A, DRP Documentation Title with Agencywide Document Access and Date Brief Description Management System (ADAMS)

Main Library (ML) Accession No.

September 3, 2021 ORISE Report of April 2021 Eight DRPs found during April 2021 Survey at Zion Nuclear Power Confirmatory Survey.

Station (ML21267A523)

August 19, 2021 Zion RAI Letter on April 2021 NRC determined request for additional Survey Results (ML21231A187) information needed (RAIs) to complete review of FSSR to reach reasonable October 14, 2021 Zion RAI No. 10 Letter on April assurance determination. A total of 11 2021 Survey Results RAIs were issued.

(ML21238A067)

March 8, 2022 Zion Nuclear Power Station, Units RAI response plus notification of 1 and 2, Response to Request for Foundation Pad discovery Additional Information Related to Partial Site Release and Recent Site Survey Activities, and Notification of Foundation Pad Discovery (ML22069A329)

March 23, 2022 Zion Nuclear Power Station, Units License Amendment Request (LAR) to 1 and 2, License Amendment License Termination Plan (LTP) to Request for the License account for residual DRPs.

Termination Plan (ML22084A058)

February 8, 2022 Email to G. Van Noordennen re: The NRC placed the review of the Final Zion and La Crosse Review Status Survey Reports (FSSRs) on hold Schedule Changes pending receipt of all survey result (ML22040A116) reports from areas re-surveyed since April 2021, confirmation that all site work is finished, and receipt of complete and adequate responses to all 11 RAIs.

1

Title with Agencywide Document Access and Date Brief Description Management System (ADAMS)

Main Library (ML) Accession No.

July 19, 2022 Regulatory Audit Plan Regarding Based on a preliminary review of the ZionSolutions' Response to March 2022 RAI responses, the NRC Request for Additional Information staff considered it would be beneficial to Related to Partial Site Release discuss the RAI responses and and Recent Site Survey Activities supporting material at a high level to (ML22200A007) facilitate a common understanding while the project remained on hold, which led to the audit.

Audit meetings were held virtually on July 19-20, 2022, and August 24-25, 2022. The discussions focused on the on extent, purpose, and technique of surveys. Discussions were based on the staffs preliminary review of the March 2022 RAI responses, and supplemental documents were not reviewed as part of the audit.

September 30, 2022 Zion Nuclear Power Station, Units ZS transmitted the survey reports for 1 and 2 - Revised Final Status areas where Final Status Surveys Survey Release Records, Final (FSSs) were reperformed (Survey Units Reports, and Discrete Radioactive (SUs) 12104, 12105, 12106, 12107, Particle Survey Report Technical 12108, 10221A, 10221B, 10221C).

Support Document(ML22279A993)

October 17, 2022 Zion Nuclear Power Station, Units ZS responded to the NRC staffs audit 1 and 2, Response to NRC Staff questions that were asked during the Questions Raised during the audit meetings and stated it had Regulatory Audit of RAI completed all FSSs and requested that Responses Conducted July 19-20, NRC complete its review of the FSSRs 2022, and August 24-25, to support the Partial Site Release 2022(ML22293A644) (PSR) request due to removal of subsurface concrete material and affirmed that all site work is complete.

November 17, 2022 Interim Summary Report - Zion The NRC issued the FSS interim audit Audit Phase 1(ML22313A053) report covering only FSSR RAI 1 and RAI 11.

March 3, 2023 Withdrawal of Zion License ZS withdrew the LTP license Amendment Request for the amendment request (LAR) and License Termination indicated it needed to re-evaluate its Plan(ML23068A012) application. Also, ZS requested that the NRC proceed with the PSR review.

2

Title with Agencywide Document Access and Date Brief Description Management System (ADAMS)

Main Library (ML) Accession No.

April 4, 2023 Zion Nuclear Power Station, Units. ZS stated that it planned to continue to 1 and 2: April 4, 2023 Zion rely on the approved LTP and the Solutions clarification regarding its final status survey process used to LTP and DRP demonstrate that the Zion Nuclear strategy(ML23116A008) Power Station (ZNPS) facility and site comply with the radiological criteria for unrestricted use specified in 10 CFR 20.1402. There have been no changes that affect ZionSolutions methods for demonstrating that the site will comply with 10 CFR 20.1402. The method for calculating the dose and the resultant dose is unchanged. ZionSolutions has implemented the DRP Survey Plan to provide reasonable assurance that we have conducted surveys adequate to detect and remediate DRPs. There is no compliance dose contribution from DRPs. The basis for the termination of the license is the demonstration that the compliance dose satisfies 10 CFR 20.1402.

June 20, 2023 ZION NPS, UNIT NOS. 1 AND 2 The NRC conducted a clarification

SUMMARY

OF MAY 4, 2023, meeting with ZS regarding the 11 FSSR CLARIFICATION MTG WITH RAIs and associated audit questions ZIONSOLUTIONS, LLC (ML23167A069). ZS said that it was REGARDING PARTIAL SITE confident that it had identified and RELEASE REQUEST FOR ZION remediated all known DRPs and NPS, UNITS 1 AND provided reasonable assurance that it 2(ML23167A069) met the regulatory requirements for unrestricted release.

As documented in the meeting summary, the NRC staff identified what information ZS needed to submit to close out the 11 FSSR RAI responses.

3

Title with Agencywide Document Access and Date Brief Description Management System (ADAMS)

Main Library (ML) Accession No.

July 6, 2023 Review of Zion Solutions NRC accepted the June 5, 2020 (as Responses to Requests for supplemented on March 3, 2021 Additional Information Related to (ML21102A397), PSR application. The Zion Nuclear Power Station, Units delay in acceptance of this request was 1 and 2 Decommissioning and due to cleanup of DRPs and in part due Estimated Partial Site Release to lack of guidance on DRP surveys.

Review Schedule(ML23186A190)

All RAIs are dispositioned except for a few.

NRC stated it would be conducting a confirmatory survey to verify that ZS identification and remediation of DRPs was effective while also verifying that the FSSs are compliant with the approved LTP.

July 13, 2023 Summary of Clarification Meeting Clarification meeting.

with ZionSolutions, LLC regarding 2023 Confirmatory Surveys for the Zion Nuclear Power Station, Units 1 and 2(ML23180A145)

August 8, 2023 Zion Nuclear Power Station, Unit Confirmatory Survey Criteria.

Nos 1 and 2: Final Summer 2023 Confirmatory Survey Criteria(ML23221A243)

August 11. 2023 Zion Nuclear Power Station, Unit The NRC evaluated the confirmatory Nos. 1 And 2: Extent Of Condition survey data against the confirmatory Request For 2023 Confirmatory survey criteria for DRPs, and informed Survey(ML23233A150) ZS on August 11, 2023 (ML23233A150) that an extent of condition evaluation of 6 SUs located in the south portion of the site near the waste rail loading area is necessary to rule out DRP cross contamination (ML23024A208).

August 25. 2023 Zion Nuclear Power Station, Units All open FSS RAIs are dispositioned.

1 and 2, Response to Summary of May 4, 2023, Clarification Meeting Regarding the Partial Site Release Request(ML23237B413) 4

Title with Agencywide Document Access and Date Brief Description Management System (ADAMS)

Main Library (ML) Accession No.

September 8, 2023 Zion Nuclear Power Station, Units ZS conducted a 100% survey of the six 1 and 2, Confirmatory Survey surveys units to evaluate the extend of Extent of Condition Review condition. One DRP (one of the 12 (ML23251A071) DRPs) was identified in SU 10211 B and removed. ZS provided its extent of condition survey results to the NRC for dose assessment.

5