ML25241A169
| ML25241A169 | |
| Person / Time | |
|---|---|
| Site: | Crystal River  |
| Issue date: | 12/18/2025 |
| From: | Allen C, Randall Fedors, Hester-Minor A, Christianne Ridge, Robertson-Demers K NRC/NMSS/DDUWP/RTAB, NRC/NMSS/DREFS/EPMB2, Reactor Decommissioning Branch |
| To: | |
| Shared Package | |
| ML25241A165 | List: |
| References | |
| EPID L-2025-LLA-0033 | |
| Download: ML25241A169 (0) | |
Text
Enclosure 1 SAFETY EVALUATION REPORT BY THE OFFICE OF NUCLEAR MATERIAL SAFETY AND SAFEGUARDS FOR FACILITY OPERATING LICENSE NO. DPR-72 ACCELERATED DECOMMISSIOINING PARTNER CR3, LLC.
CRYSTAL RIVER UNIT 3 NUCLEAR GENERATING STATION DOCKET NO. 50-302 December 18, 2025 Contributors Chris Allen, NMSS Kathryn Robertson-DeMers, NMSS Randall W. Fedors, NMSS Amy Minor, NMSS Christianne Ridge, NMSS
i Table of Contents TABLE OF CONTENTS................................................................................................................................I LIST OF TABLES.........................................................................................................................................II LIST OF FIGURES.......................................................................................................................................II LIST OF ACRONYMS AND ABBREVIATIONS.........................................................................................III 1.
INTRODUCTION....................................................................................................................................1 2.
APPLICABLE REGULATIONS.............................................................................................................1 3.
BACKGROUND.....................................................................................................................................2 4.
TECHNICAL EVALUATIONS................................................................................................................4
4.1 DESCRIPTION
OF PROPERTY TO BE RELEASED.................................................................................4 4.2 PROPERTY RELEASE EFFECTS EVALUATION.....................................................................................6 4.2.1 Emergency Planning and Physical Security Evaluation..................................................6 4.2.2 Effluent Release, Environmental Monitoring and Offsite Dose Calculation Manual Evaluation........................................................................................................................6 4.2.3 Siting Criteria and Other Applicable Requirements.........................................................8 4.2.4 Release Schedule Evaluation..........................................................................................8 4.2.5 Historical Site Assessment and Classification.................................................................8 4.2.6 Final Status Survey Design for Soils.............................................................................11 4.2.7 Non-impacted Survey Unit Results................................................................................20 4.2.8 Impacted Survey Unit Final Survey Results and Reporting...........................................22 4.3 QUALITY ASSURANCE (QA)/QUALITY CONTROL (QC).....................................................................25 4.4 ISOLATION AND CONTROLS EVALUATION........................................................................................26 4.5 GROUNDWATER............................................................................................................................26 4.5.1 Groundwater Flow Patterns and Potential Offsite Effluent Discharge...........................27 4.5.2 Residual Radioactivity in Groundwater..........................................................................29 5.
NRC INSPECTIONS AND CONFIRMATORY SURVEYS...................................................................31 6.
ENVIRONMENTAL REVIEW...............................................................................................................33 7.
EPA-NRC MEMORANDUM OF UNDERSTANDING (MOU)..............................................................33 8.
PUBLIC COMMENTS..........................................................................................................................33 9.
STATE CONSULTATION....................................................................................................................33
- 10. CONCLUSIONS...................................................................................................................................33
ii List of Tables Table 1. CR3 Phase II PSR Survey Units.....................................................................................5 Table 2. Background Measurement Range for Open Land Survey Units...................................18 Table 3. Non-impacted Survey Unit Sample Numbers................................................................21 Table 4. Surface and Subsurface Cs-137 Results by Survey Unit1, 2..........................................22 Table 5. Survey Unit Characterization and Final Status Survey Sample Numbers.....................23 Table 6. Impacted Surface Soil Cs-137 Results by Survey Unit1................................................24 List of Figures Figure 1. Overview of Survey Areas and Non-Impacted Areas.....................................................5 Figure 2. Phase I PSR ORISE and Phase II PSR Background Reference Areas.......................14 Figure 3. Box and Whiskers Plot of Cs-137 Concentrations for the BRAs and Survey Units.....16
iii List of Acronyms and Abbreviations ADAMS Agencywide Documents Access and Management System ADP ADP CR3, LLC or ADP CR3 Accelerated Decommissioning Partner entity to which the NRC license is issued ALARA As Low as Reasonably Achievable Am-241 Americium-241 AREOR Annual Radiological Environmental Operating Report BRA Background Reference Area BTV Background Threshold Value C-14 Carbon-14 CASA Coal Ash Storage Area CFR Code of Federal Regulations cm centimeter Co-60 Cobalt-60 CR3 Crystal Rive Unit 3 Nuclear Generating Plant CREC Crystal River Energy Complex Cs-137 Cesium-137 DECON A method of decommissioning, in which structures, systems, and components that contain radioactive contamination are removed from a site and safely disposed at a commercially operated low-level waste disposal facility, or decontaminated to a level that permits the site to be released for unrestricted use shortly after it ceases operation DEF Duke Energy Florida DQO Data Quality Objective EPA U.S. Environmental Protection Agency Eu-152 Europium-152 Eu-154 Europium-154 Fe-55 Iron-55 FSS Final Status Survey FSSR Final Status Survey Report GEL GEL Laboratories, LLC H-3 tritium HSA Historical Site Assessment HTD Hard to Detect I & C Isolation and Control IFB Indistinguishable from Background in inch ISFSI Independent Spent Fuel Storage Installation m2 square meter MARLAP Multi-Agency Radiological Laboratory Analytical Protocols Manual MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC Minimum Detectable Concentration
iv MDCR Minimum Detectable Count Rate mrem/y millirem per year MW Monitoring Well NaI Sodium Iodide Ni-59 Nickel-59 Ni-63 Nickel-63 NIA Non-impacted Area NRC U.S. Nuclear Regulatory Commission ODCM Offsite Dose Calculation Manual OLA Open Land Area ORISE Oak Ridge Institute for Science and Education pCi/g picoCurie per gram PSDAR Post-Shutdown Decommissioning Activities Report PSR Partial Site Release Pu-239 Plutonium-239 QA Quality Assurance QC Quality Control R16Y North Shipping Yard RA-01 Reference Area 01 RA-02 Reference Area 02 RA-03 Reference Area 03 RA-04 Reference Area 04 rem Roentgen equivalent man REMP Radiological Environmental Monitoring Program RESRAD The RESRAD family of computer codes is a regulatory tool for evaluating radioactively contaminated sites, specifically designed to help determine the allowable RESidual RADioactivity in site cleanup RG Regulatory Guide SAFSTOR Safe Storage SEAL SeaLand Container Storage Area SER Safety Evaluation Report Sr-90 Strontium-90 Tc-99 Technetium-99 UPL Upper Prediction Limit VSP Visual Sample Plan WRS Wilcoxon Rank Sum
1 1.
INTRODUCTION By letter dated, February 10, 2025 [Agencywide Documents Access and Management System (ADAMS) Accession Number (No.) ML25041A178], as supplemented on June 18, 2025 (ADAMS Accession No. ML25170A017), Accelerated Decommissioning Partners (ADP) Crystal River Unit 3 (CR3), LLC (ADP or ADP CR3) requested the U.S. Nuclear Regulatory Commission (NRC) approve a partial site release (PSR) at the CR3 Nuclear Generating Plant.
ADP CR3 requested unrestricted release of 618 acres, classified as radiologically non-impacted or Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) Class 3, from License No. DPR-72. In addition, ADP CR3 requested the NRC remove another 3,854 acres of property, classified as radiologically non-impacted, from License No. DPR-72 as approved on January 2, 2020 (ADAMS Accession No. ML19339G509). ADP CR3 proposed to amend the Technical Specifications Site description of the property released by the PSRs and to remove language no longer applicable to decommissioning activities.
2.
APPLICABLE REGULATIONS The regulations in Title 10 Code of Federal Regulations (CFR) Part 50.83, Release of part of a power reactor facility or site for unrestricted use, establish the requirements for releasing property prior to approval of a license termination plan. For the release of impacted areas, 10 CFR 50.83(d) requires the licensee to submit a license amendment for the release of the property which includes:
1.
The information specified in paragraphs (b)(1) through (b)(3) of this section; 2.
The methods used for the results obtained from the radiation surveys required to demonstrate compliance with the radiological criteria for unrestricted use specified in 10 CFR 20.1402; and 3.
A supplement to the environmental report, under §51.53, describing any new information or significant environmental change associated with the licensees proposed release of the property.
The regulations in 10 CFR 50.83(b)(1)-(3) require the licensee to submit:
1.
The results of the evaluations performed in accordance with paragraphs (a)(1) and (a)(2) of 10 CFR 50.83; 2.
A description of the part of the facility or site to be released; 3.
The schedule for release of the property; Finally, the regulations in 10 CFR 50.83(a)(1)-(3) require the licensee to do the following:
1.
Evaluate the effect of releasing the property to ensure that -
i.
The dose to individual members of the public does not exceed the limits and standards of Subpart D, Radiation Dose Limits for Individual Members of the Public, 10 CFR Part 20, Standards for Protection Against Radiation; ii.
There is no reduction in the effectiveness of emergency planning or physical security; iii.
Effluent releases remain within license conditions; iv.
The environmental monitoring program and offsite dose calculation manual are revised to account for the changes; v.
The siting criteria of 10 CFR Part 100, Reactor Site Criteria, continue to be met; and
2 vi.
All other applicable statutory and regulatory requirements continue to be met.
2.
Perform a Historical Site Assessment of the part of the facility or site to be released; and 3.
Perform surveys adequate to demonstrate compliance with the radiological criteria for unrestricted use specified in 10 CFR 20.1402, Radiological criteria for unrestricted use, for impacted areas.
After receiving a license amendment application from the licensee for the release of an impacted area, 10 CFR 50.83(e) states that the NRC shall:
1.
Determine whether the licensee has adequately evaluated the effect of releasing the property as required under (a)(1) of 10 CFR 50.83; 2.
Determine whether the licensees classification of any release areas as non-impacted is adequately justified; 3.
Determine whether the licensees radiation survey for an impacted area is adequate; and 4.
Upon determining that the licensee's submittal is adequate, approve the licensee's amendment application.
3.
BACKGROUND The Crystal River Energy Complex (CREC) is located on 4,738 acres on the Gulf of Mexico, approximately 7.5 miles northwest of the City of Crystal River, and approximately 75 miles north of Tampa, Florida. Duke Energy Florida (DEF) operated a 2,609-megawatt thermal, single-unit pressurized light-water reactor that was co-located with coal-fired plants and natural gas-fired plants. The NRC issued an operating license on December 3, 1976, with the reactor beginning commercial operation on March 13, 1977. CR3 last produced power in September 2009, while shutting down for Refuel 16. During activities to replace steam generators, a portion of the containment concrete wall delaminated. While completing repairs, additional delamination occurred.
On February 20, 2013 (ADAMS Accession No. ML13056A005), DEF formally notified the NRC that it had permanently ceased power operations at CR3 and had removed fuel from the reactor vessel. On June 26, 2019 (ADAMS Accession No. ML19177A080), DEF submitted a Post-Shutdown Decommissioning Activities Report (PSDAR), choosing to place the facility in long-term storage, i.e. (the SAFSTOR decommissioning option). By letter dated June 14, 2019 (ADAMS Accession No. ML19170A209), as supplemented by letters dated January 17, 2020 (ADAMS Accession No. ML20017A216), and March 5, 2020 (ADAMS Accession No. ML20065K737), DEF requested, on behalf of itself and ADP CR3 that the NRC consent to the transfer of license authority from DEF to ADP CR3. The NRC approved the transfer on April 1, 2020 (ADAMS Accession No. ML20069A023). On June 26, 2019 (ADAMS Accession No. ML19177A080), ADP CR3 submitted a revised PSDAR contingent upon the transfer of the CR3 license authority to ADP CR3. The revised PSDAR changed the decommissioning approach from SAFSTOR to the immediate decontamination and dismantlement of the facility (i.e. the DECON decommissioning option).
By letter dated January 22, 2019 (ADAMS Accession No. ML19022A076), as supplemented by e-mail dated October 24, 2019 (ADAMS Accession No. ML19310D860), DEF submitted a request to the NRC for approval of the Phase I partial site release (Phase I PSR) for unrestricted use of approximately 3,854 acres (1,600 hectare) of the 4,738-acre (1917-hectare)
CREC. On January 2, 2020 (ADAMS Accession No. ML19339G509), the NRC approved the unrestricted release of the property.
3 The areas proposed for release under this PSR request (Phase II PSR) consisted of seven non-impacted areas and two MARSSIM Class 3 open land area (OLA) survey units. ADP designed and executed surveys of these non-impacted and Class 3 areas using guidance in MARSSIM, dated August 2000 (ADAMS Accession No. ML003761445), NUREG-1757, Volume 2, Revision 2, Consolidated Decommissioning Guidance - Characterization, Survey, and Determination of Radiological Criteria (ADAMS Accession No. ML22194A859) and CR3 implementing procedures. ADP performed background reference area analyses using guidance from MARSSIM and NUREG-1505, A Nonparametric Statistical Methodology for the Design and Analysis of Final Status Decommissioning Surveys, Revision 1, (ADAMS Accession No. ML061870462). ADP supplemented the PSR amendment request with several documents, listed below, which provided a basis for the licensees compliance determinations with 10 CFR 50.83.
- Crystal River Unit 3 Supporting Information for Request for 2nd Partial Site Release (Attachment 1) (ADAMS Accession No. ML25041A179)
- CR3 Non-Impacted Areas Partial Site Release Phase II Report (Attachment 2) (ADAMS Accession No. ML25041A180)
- CR3 R16Y Area Partial Site Release Phase II Report (Attachment 3)
(ADAMS Accession No. ML25041A181)
- CR3 CASA Area Partial Site Release Phase II Report (Attachment 4)
(ADAMS Accession No. ML25041A182)
- CR3 SeaLand Area Partial Site Release Phase II Report (Attachment 5)
(ADAMS Accession No. ML25041A185)
- Historical Site Assessment for Crystal River 3 (Attachment 6) (ADAMS Accession No. ML25041A186)
- Crystal River Unit 3 - Partial Site Release Request January 2019 (Attachment 7) (Accession No. ML25041A187)
- TSD - Groundwater Well and Withdrawal Permit Limits Under the Florida Department of Environmental Protection Regulations (Attachment 8) (ADAMS Accession No. ML25041A188)
- TBD - Basis for No Contaminated Water Dose at CR3 (Attachment 9)
(ADAMS Accession No. ML25041A189) 0: CR3 Site Characterization Survey Report (CHAR-01) Impacted Open Land Survey Areas (Attachment 10) (ADAMS Accession No. ML25041A190) 1: CHAR-06 CR3 Non-impacted Open Land Survey Areas (Attachment
- 11) (ADAMS Accession No. ML25041A192) 2: TSD - Evaluation of Radiochemical Analysis of Well Water Samples from the Proposed Partial Site Release at Crystal River 3 Nuclear Generating Plant (Attachment 12) (ADAMS Accession No. ML25170A032) 3: Evaluation of Soil Background Concentrations at Crystal River Unit 3 (Attachment 13) (ADAMS Accession No. ML25170A033)
These documents summarized the results of characterization and final status surveys, the historical site assessment (HSA), discussion of groundwater conditions, Phase I PSR information, and background reference area (BRA) analyses. Future references to these documents in the Safety Evaluation Report (SER) will be by attachment number, e.g.,.
NRC staff conducted an audit from May 12, 2025, through May 29, 2025, during which ADP CR3 provided supplemental information which was incorporated into the Phase II PSR, Revision
4 1 (ADAMS Accession No. ML25170A018) submitted June 18, 2025. The audit responses and the revised PSR included sufficient data and information to enable an independent re-creation and evaluation of both the derived results and the survey activities.
4.
TECHNICAL EVALUATIONS The technical evaluation in this SER covered only the Phase II PSR which focused on the proposed release of 618 acres of radiologically impacted and non-impacted land. The Phase II PSR included Class 3 survey units contained within non-impacted areas whereas the previously approved Phase I PSR included only non-impacted areas. Adding further complexity to the technical evaluation, the Phase II PSR included non-impacted areas adjacent to Class 1, Class 2, and Class 3 areas which focused staffs attention on effective isolation and control (I&C) procedures as decommissioning and remediation in the reactor area proceeds. These complexities prompted the staff to perform a more extensive review of the Phase II PSR versus the Phase 1 PSR. With the inclusion of impacted areas, the PSR served as a standalone document containing the licensees approach to demonstrating compliance with release criteria and final status survey reports (FSSRs) for Class 3 survey units. Unless stated otherwise in the remainder of this SER, PSR refers to the Phase II PSR.
4.1 Description of Property to be Released In accordance with 10 CFR 50.83(b)(2) and (d)(1), a description of the site to be released must be included as a part of the PSR. Attachment 1 of the Phase II PSR described both the impacted and non-impacted areas including boundaries and maps for the 618 acres proposed for release. Attachments 2, 3, 4, 5, and 6 of the Phase II PSR provided a detailed description of all areas proposed for release.
5 Figure 1. Overview of Survey Areas and Non-Impacted Areas Figure 1, reproduced from Attachment 1, Figure 3 of the Phase II PSR, shows the CR3 survey units inclusive of NIA-01 through NIA-06, the North Shipping Yard (R16Y), the Coal Ash Storage Area (CASA), and the SeaLand Container Storage Area (SEAL) which were proposed for release. Table 1 below, reproduced from Attachment 1, Table 1, Description of the PSR Land Survey Areas, summarizes the survey unit description, classifications, and sizes. Detailed discussions, NRC evaluations, and regulatory findings are included in subsequent sections of this report.
Table 1.
CR3 Phase II PSR Survey Units Survey Unit ID Survey Unit Description Class Size (acres)
Size (m2)
NIA-01 Northern most section of the Unit 4 & 5 operating plant footprint NIA 98.0 396,780 NIA-02 Southern section of the Unit 4 & 5 operating plant footprint NIA 95.3 385,907 NIA-03 Southern section of the Unit 4 & 5 coal yard and open land area NIA 99.3 402,051 NIA-04 Mid-western section of the Unit 4 & 5 switchyard and open land area NIA 77.9 315,423 NIA-05 Mid-eastern section of the Unit 4 & 5 switchyard and open land area NIA 90.1 364,690
6 NIA-06 Southern section on the licensed footprint below the intake canal NIA 86.7 351,202 CASA Coal Ash Storage Area NIA 66.4 268,846 R16Y North Shipping Yard 3
3.8 15,444 SEAL SeaLand Container Storage Area (within NIA-06) 3 0.7 2,712 Totals 618.2 2,503,055 Based on the NRC staff evaluation of items discussed in this section of the SER, the NRC concludes that the requirements of 10 CFR 50.83(b)(2) for non-impacted areas and 10 CFR 50.83(d)(1) for impacted areas are satisfied.
4.2 Property Release Effects Evaluation 4.2.1 Emergency Planning and Physical Security Evaluation The regulations in 10 CFR 50.83(a)(1)(ii) require that the release of the property not reduce the effectiveness of either emergency planning or physical security. The applicant stated that no credit is taken for this land in either the Emergency Plan or Security Plan, and Figure 3 in showed that the Independent Spent Fuel Storage Installation (ISFSI) is not located in the land proposed for release. Staff reviewed the ISFSI-Only Emergency Plan (ADAMS Accession No. ML21076A386). Staff also reviewed the physical security plan (ADAMS Accession No. ML24242A224). Staff determined that the land proposed for release was not credited in either the Emergency Plan or the security plan. Therefore, the staff finds that the release of the proposed property does not reduce the effectiveness of either emergency planning or physical security.
4.2.2 Effluent Release, Environmental Monitoring and Offsite Dose Calculation Manual Evaluation The requirement in 10 CFR 50.83(a)(1)(iv) specifies that both the environmental monitoring program and the offsite dose calculation manual (ODCM) are revised to account for the changes. Guidance in Appendix K of NUREG-1757 Volume 2 recommends performance of a pathway assessment to ensure that the proposed release areas are not affected by radioactivity from onsite locations. The NRC recognizes radiological exposure pathways, both surface and subsurface (i.e., atmospheric and groundwater offsite pathways) as the vehicle by which the public may become exposed to radioactivity released from nuclear facilities. These pathways are determined from the type and amount of radioactive material released, the environmental transport mechanism, and how the plant environs are used.
For the atmospheric pathway, the licensee conducted a review of the current Radiological Environmental Monitoring Program (REMP) sampling locations and thermoluminescent dosimeter (TLD) positions and determined that no changes to the REMP were required for the reduction of the Controlled Area to 265 acres. The 2022 Annual Radiological Environmental Operating Report, dated April 18, 2023 (ADAMS Accession No. ML23108A266), the Annual Radiological Environmental Operating Report 2023, dated April 30, 2024 (ADAMS Accession No. ML24121A121), and the 2024 Annual Radiological Environmental Operating Report, dated May 7, 2025 (ADAMS Accession No. ML25127A372) showed that the direct-dose measurements have met the 10 CFR 20, Subpart D public dose limits of 100 millirem/year (mrem/y) and 0.002 roetgen equivalent man per hour (rem/hr). ADP also conducted surveys
7 demonstrating the absence of plant-related residual radioactivity above background levels.
ADP CR3 strictly controlled effluents to ensure that release of radioactivity to the environment was maintained as low as reasonably achievable (ALARA) and did not exceed federal release limits. The NRC finds that the release of the property will not impact the ability of the licensee to meet public dose limits and the potential for detecting an unmonitored radiological release to occur beyond the boundary.
ADP defined the new Controlled Area as shown in Attachment 1, Figure 13, New Controlled Area Boundary of the Phase II PSR. Additional TLD locations will be placed around the Controlled Area as shown in Attachment 1, Figure 14, TLD Locations Along Site Boundary of the PSR. These locations will be included in the TLD monitoring program used to assess boundary dose and dose to members of the public. Changes to the ODCM will be required when the new Controlled Area/Site Boundary becomes effective to re-define terms and account for any dispersion factor changes.
For the offsite groundwater pathway, staff evaluated groundwater flow patterns across the site considering the new proposed site boundary. Staff evaluated the details of groundwater flow in SER section 4.5.1. Prior to approval of the Phase I PSR, offsite groundwater flow only occurred directly to the gulf. After approval of the Phase I PSR in 2020, offsite groundwater only flowed to the coastal swamps with the primary component flowing between and into the intake and discharge canals. For the Phase II PSR request, staff determined in SER section 4.5.1 that the situation arises where onsite groundwater flowed from the eastern side of the berm area (onsite) into the proposed PSR land areas NIA-06, NIA-05, and possibly NIA-04. Staff identified several REMP wells (wells CR3-1, CR3-10, CR3-4, and paired well set CR3-3S and CR3-3D) that are located such that residual radioactivity would be detected prior to offsite migration across the new proposed site boundary. The ODCM requires continued measurements of radioactivity in groundwater from these wells. If radioactivity is detected in any of these wells, the licensee would need to update the ODCM to include a dose calculation method for offsite groundwater effluents following guidance in NUREG-1301 (Offsite Dose Calculation Manual Guidance:
Standard Radiological Effluent Controls for Pressurized Water Reactors, ADAMS Accession No. ML091050061) and Regulatory Guide (RG) 1.21 (Measuring, Evaluating, and Reporting Radioactive Material in Liquid and Gaseous Effluents and Solid Waste, ADAMS Accession No. ML21139A224).
The NRC staff concludes that the release of the land has no negative effect on the environmental monitoring program, the ODCM, or the established plant programs used to maintain the effluent releases within the license conditions. Based on the absence of high energy systems during decommissioning for dispersal of atmospheric releases and the isolation and controls (I&Cs), discussed in SER section 4.4, to control resuspension, the NRC finds that releasing the land will not impact the potential for release, via both atmospheric and groundwater pathways, beyond the Owner Controlled Area.
Staff identified three items for the inspection program to review once the ODCM is revised following approval of the PSR: (i) the new boundary is incorporated, (ii) possible revision of the dispersion terms (e.g., dispersion factors) to account for the new CR3 site Controlled Area; and (iii) if radionuclide detections occur at monitoring well locations CR3-1, CR3-10, CR3-4 and CR3-3S/D, then the addition of a calculation method to the ODCM for dose due to offsite groundwater effluents.
8 4.2.3 Siting Criteria and Other Applicable Requirements ADP stated that the release of the subject property has been reviewed with respect to the 10 CFR 100 criteria. ADP concluded that the requirements of 10 CFR 100 are either not impacted (e.g., 10 CFR 100.11, Determination of exclusion area, low population zone, or population center distance, or 10 CFR 100, Appendix A, Seismic and Geologic Siting Criteria for Nuclear Power Plants) or are not applicable (e.g., 10 CFR 100, Subpart B, Evaluation Factors for Stationary Power Reactor Site Applications on or After January 10, 1997). Also, ADP committed to controlling the Controlled Area and maintaining the ability to remove members of the public from the Controlled Area in the case of a radiological emergency. In addition, ADP asserted that all other statutory and regulatory requirements will continue to be met via site policies and procedures because the early release of the subject property does not adversely impact site policies and procedures.
The purpose of 10 CFR 100 is to help assure that radiological doses from normal operation and postulated accidents will be acceptably low, that natural phenomena and potential man-made hazards will be appropriately accounted for in the design of the plant, that site characteristics are such that adequate security measures to protect the plant can be developed, and that physical characteristics unique to the proposed site that could pose a significant impediment to the development of emergency plans are identified. These regulations are most relevant when fuel is in the reactor and the reactor is operating. ADP stated that the spent fuel has been transferred to the ISFSI. The most recent Crystal River inspection report, dated July 28, 2025 (ADAMS Accession No. ML25205A188), which was performed under the Actively Decommissioning (DECON), No Fuel in the Spent Fuel Pool category, confirmed this. In addition, as documented in an inspection report dated September 23, 2024 (ADAMS Accession No. ML24261C022), ADP removed the segmented reactor vessel from the site for disposal.
With the spent fuel no longer being stored in the spent fuel pool and the reactor vessel removed from the site, the staff determined that ADPs conclusions regarding the 10 CFR 100 requirements being either not impacted or not applicable are reasonable. Staff also determined that the proposed release of these land areas will not impair ADPs ability either to control the Controlled Area or to remove members of the public from the Controlled Area in a radiological emergency event. Finally, because releasing the land will have no impact on ADP policies and procedures used to fulfill statutory and regulatory requirements, the staff determined that the licensees compliance with other statutory and regulatory requirements will be unaffected by the PSR.
4.2.4 Release Schedule Evaluation For non-impacted areas, 10 CFR 50.83(b)(3) requires a schedule for the release of the property.
ADP identified their intent to begin undertaking activities associated with the release of the subject property from the Part 50 License on or before December 2025 (ADAMS Accession No. ML25170A019). In their acceptance letter dated March 20, 2025 (ADAMS Accession No. ML25069A435), the NRC staff communicated to ADP that they expected to complete their review of the PSR by December 31, 2025. Therefore, the staff finds releasing the subject property on or before December 2025 acceptable.
4.2.5 Historical Site Assessment and Classification ADP prepared an HSA, which was included in its entirety in Attachment 6 of the PSR, in accordance with the guidance in Section 3.0, Historical Site Assessment, of MARSSIM. ADP performed an investigation of historical information pertaining to radioactive or hazardous
9 materials for the site and its surroundings, including the 618 acres subject to this PSR, and used this information to establish initial classifications of the site land areas as impacted or non-impacted. The HSA focused on historical events and routine operational processes that resulted or potentially resulted in radiological and hazardous material contamination of plant systems, onsite buildings, surface, and subsurface soils within the Controlled Area as well as support structures, OLAs and subsurface soils outside the CR3 Controlled Area, but within the Owner Controlled Area. ADP reviewed the following 10 CFR 50.75(g) files and compiled the information into the HSA: employee interviews; incident files; special survey and operational radiological survey records; Health Physics and Operator logs; subsurface investigations reports; Florida Department of Environmental Protection records; American Nuclear Insurers inspection reports; the CR3 ODCM; the CR3 Final Safety Analysis Report; the CR3 Spill Prevention, Control and Countermeasures Plan; the CR3 Storm Water Pollution Prevention Plan; the CR3 Annual Radioactive Effluent Release Reports; and the CR3 Annual Radiological Environmental Monitoring Reports.
4.2.5.1 Non-Impacted Areas Non-impacted areas, as defined in 10 CFR 50.2, are areas with no reasonable potential for residual radioactivity in excess of natural background or fallout levels. MARSSIM elaborates on this definition by describing non-impacted areas as those having no radiological impact from site operations, thus, having no reasonable potential for residual radioactivity. ADP designated the NIA-01 through NIA-06 and CASA survey units as non-impacted areas in the PSR.
ADP explained that during plant operations, DEF occasionally released water from the Station Drain Tank and Turbine Sump to the Settling Ponds rather than the discharge canal. The West Settling Pond received non-radioactive water from Units 1 and 2 coal plant boiler wastewater and sewage treatment plant discharge water. The East Settling Pond infrequently received secondary liquid effluent from Unit 3. In December 2011, DEF removed sediment, as well as contoured the sides of the East Settling Pond, and relocated the sediment to the CASA. The HSA initially classified the CASA as a MARSSIM Class 3 area; however, the evaluation and classification recommendation neither considered the specifics of radiological controls implemented by DEF nor sediment analysis performed prior to removal of material from the ponds. Attachment K of Attachment 4 of the PSR provided supplemental information to validate reclassification of the CASA.
On May 15, 2009, American Nuclear Insurers recommended soil and vegetation be collected from the Settling Pond banks and analyzed for gamma emitting radionuclides. The State of Florida Department of Health Bureau of Radiation Control (DOH) collected soil samples during the years 2009 - 2014. In 2009, Cs-137 soil sample results from the East Settling Pond ranged from less than 0.022 pCi/g to 0.299 pCi/g. A single sample contained Co-60 at a concentration of 0.027 pCi/g at the input pipe to the pond. The West Settling Pond samples had a maximum Cs-137 concentration of 0.190 pCi/g with no detectable Co-60. The East and West Settling Pond had average Cs-137 concentrations of 0.08 pCi/g and 0.06 pCi/g, respectively. In 2010 and 2011, the Cs-137 concentration in the Settling Ponds ranged from 0.02 to 0.137 pCi/g and 0.076 to 0.097 pCi/g, respectively. The 2010 and 2011 DOH sampling did not detect any Co-60 residual radioactivity. The maximum Cs-137 concentration for 2011, prior to the removal of the dredging, and the average concentrations from 2009, 2010, and 2011, are less than the background threshold value (BTV) discussed in SER section 4.2.6.2.
ADP further explained that, on December 13, 2011, DEF collected and analyzed four samples from the East Settling Pond for Cs-137 with two samples being less than the minimum
10 detectable concentration (MDC) and the others at 0.016 pCi/g and 0.027 pCi/g. After determining there was no detectable plant derived activity above background for Cs-137, site Radiological Control staff authorized the relocation of the dredge to the CASA. Furthermore, the coal ash heavy metal in the ground water remediation effort resulted in the removal of the coal ash material from the CASA in 2016 or 2017 which was believed to include the Settling Pond dredge. Based on the information above, ADP reclassified the CASA as non-impacted.
Except R16Y and SEAL, ADP identified the areas associated with the Phase II PSR as non-impacted based on a review of the sites operating history, historical incidents, and operational surveys. Characterization surveys conducted between April 28 and May 12, 2023, for NIA-01, NIA-02, NIA-03, NIA-04, NIA-05, and NIA-06, and characterization and final status surveys conducted on March 29, 2022, and in November 2024, respectively, for the CASA supported this classification. The HSA indicated no use of these survey units for plant operations, storage or burial of radioactive material or waste, or any occurrences of spills, leaks, or uncontrolled release of radioactive material. Based on the HSA, supplemental information, radiological surveys and sampling results, the NRC concludes that the HSA supports the classification of these areas as non-impacted areas.
4.2.5.2 Impacted Areas An impacted area, as defined in 10 CFR 50.2, is an area with some reasonable potential for residual radioactivity in excess of natural background or fallout levels. Impacted areas have potential for contamination (based on historical data) or contain known contamination (based on past or preliminary radiological surveillance). These areas are further divided into three classifications based on the potential for contamination as described in Section 4.4, Classify Areas by Contamination Potential of MARSSIM. ADP designated R16Y and SEAL survey units, which are bounded on all sides by non-impacted areas, as MARSSIM Class 3 survey units based on a history of radioactive material storage in these areas.
Survey Unit R16Y, also referred to as the North Shipping Yard, is located north of CR3 and north of the Switchyard. The HSA identified that R16Y was used as a radioactive material shipment staging area during Refuel Outage #16. DEF conducted a baseline survey of the area in June 2009, prior to storing radioactive material in the area, with a release survey performed in July 2013. The release survey identified no plant derived residual radioactivity with the results consistent with the baseline survey. ADP conducted a characterization survey in March 2022.
Only three of eight samples contained trace amounts of Cs-137 with a maximum concentration of 0.029 pCi/g. The samples contained no other plant derived radionuclide above the MDC.
The HSA contained no record of spills, leaks, or uncontrolled releases of radioactive material in R16Y.
Survey Unit SEAL is located within the eastern portion of NIA-06 inside the railroad loop. The HSA identified that SEAL was used as a SeaLand Container Storage Area during Refuel Outage #16. DEF conducted a baseline survey in May 2009, prior to storing radioactive material in the area, with a release survey performed in July 2010. While dose rates were consistent with background, they were slightly higher during the release survey as compared to the baseline survey. However, surface samples analyzed from the release survey identified no plant derived residual radioactivity. The HSA contained no record of spills, leaks, or uncontrolled releases of radioactive material in the SEAL. Characterization sampling conducted in March 2022 identified no residual radioactivity exceeding the MDC for all plant derived radionuclides. Based on the information above, the NRC concludes that R16Y and SEAL have
11 little potential for contamination and are appropriately classified as MARSSIM Class 3 survey units.
4.2.5.3 Conclusions The NRC staff reviewed the licensees justification for concluding that NIA-01 through NIA-06 and the CASA are non-impacted areas and that R16Y and SEAL are impacted areas as defined in 10 CFR 50.2. The NRC staff evaluated the licensees HSA as it relates to the guidance contained in MARSSIM, Sections 2.4 and 3.0, and NUREG-1757, Volume 2, Revision 2, Section 4.1, Historical Site Assessment. Based on the above considerations, the NRC staff finds that the licensees classification of NIA-01 through NIA-06 and CASA as non-impacted, and R16Y and SEAL as impacted, is consistent with the definitions in 10 CFR 50.2.
4.2.6 Final Status Survey Design for Soils The requirement in 10 CFR 20.1501(a)(2) specifies that surveys of areas be conducted to evaluate the concentrations or quantities of residual radioactivity. The primary objectives of a final status survey (FSS), are to verify the survey unit classification, demonstrate the potential dose from residual radioactivity in each survey unit is below the required release criterion, and demonstrate that the potential dose from small areas of elevated activity, when combined with other residual radioactivity in a survey unit, is below the release criterion. ADP planned, designed, and implemented surveys as well as assessed the resulting data, in accordance with guidance in MARSSIM, NUREG-1757, Volume 2, and site procedures. ADP included both Data Quality Objectives (DQOs) and the survey methodology in detailed survey packages.
The FSS plan included a radiological assessment of 618 acres of impacted and non-impacted OLAs. ADP divided this acreage amongst the two Class 3 survey units and seven non-impacted survey units as shown in SER Table 1. The classification of a survey unit, as defined in MARSSIM Section 4.4, is meant to establish the level of survey effort needed for FSSs with MARSSIM, Section 2.5.2 describing the FSS components by classification. Attachments 2 and 4 of the PSR discussed the DQOs, as well as the survey and sampling approach for NIA-01 through NIA-06 and the CASA, respectively. ADP conducted both a characterization survey and obtained FSS samples in the CASA. 0 described the characterization survey approach for OLAs, including the R16Y and the SEAL, for decommissioning planning and ensuring worker safety. Attachments 3 and 5 outlined the approach to FSS design for the R16Y and SEAL, respectively. Surveys included surface scans, field measurements, and random soil sampling. ADP supplemented random measurements with investigative in areas with audible responses above the investigation level or localized background during scanning as well as judgmental sampling in areas where material may have concentrated (e.g., low-lying areas).
ADP opted to apply Scenario B, which is discussed in NUREG-1757, Volume 2, Appendix G, and NUREG-1505, Chapters 6, 7, and 13, for release of survey units. Attachment 13 described the data analysis for the BRAs. Attachment 1 described the approach to demonstrating that the survey units were indistinguishable from background (IFB).
4.2.6.1 Radionuclides of Concern and Hard-to-Detect Radionuclides Appendix A, "Nuclide Suite Development," to Chapter 6 of Revision 2 of the License Termination Plan (ADAMS Accession No. ML24089A036) described a systematic approach to
12 identifying the initial suite of potential radionuclides of concern for decommissioning and the initial deselection process for excluding insignificant contributors. The total calculated dose from all discounted nuclides in NUREG/CR-4289, "Residual Radionuclide Contamination Within and Around Commercial Nuclear Power Plants" (ADAMS Accession ML8603140488) analysis equated to approximately 0.09 percent of the dose and in the NUREG/CR-3474, Long Lived Activation Products in Reactor Materials (ADAMS Accession Number 8409200285) analysis 0.34 percent of the dose assuming a Resident Farmer scenario. ADP retained several radionuclides because they either have methods of production in addition to activation of reactor components, were observed in the 10 CFR Part 61 waste stream analysis or were observed in site characterization samples. ADPs initial suite of radionuclides included Americium-241 (Am-241), Carbon-14 (C-14), Cobalt-60 (Co-60), Cesium-137 (Cs-137), Europium-152 (Eu-152),
Europium-154 (Eu-154), Iron-55 (Fe-55), Tritium (H-3), Plutonium-239 (Pu-239), Nickel-63 (Ni-63), Strontium-90 (Sr-90),Technetium (Tc-99), and Nickel-59 (Ni-59). ADP sent samples collected as a part of the Phase II PSR to an offsite laboratory that analyzed the samples for these thirteen radionuclides or the subset containing the hard-to-detect radionuclides (i.e., Am-241, C-14, Fe-55, H-3, Pu-239, Ni-59, Ni-63, Sr-90, and Tc-99).
DEF analyzed the Phase I PSR BRA and survey unit soil, sediment, and water samples using onsite laboratory gamma spectroscopy. Additionally, the onsite laboratory analyzed water samples for tritium. Partial Site Release of the Crystal River Energy Complex Radiological Survey Final Report (ADAMS Accession No. ML19029A008), submitted with the Phase I PSR, summarized the soil and sediment results for Cs-137 and Co-60. DEF sent twenty-one (21) soil and sediment samples offsite for analysis of Cs-137, Co-60, Sr-90, Fe-55, Ni-63, and gross alpha/beta. Of these samples twenty-one (21) had positive alpha results above the MDC and sixteen (16) samples had positive beta results above the MDC. The maximum alpha and beta concentrations were 38 pCi/g and 25.7 pCi/g, respectively. Two samples had tritium results above the MDC and one sample had Ni-63 above the MDC. DEF collected investigative samples in response to the greater than MDC tritium and Ni-63 results from the areas of sample collection. Analyses of the investigative samples detected neither tritium, Ni-63 nor other radionuclides. Both onsite and offsite analysis identified Cs-137 above MDC, but no other plant derived radionuclides other than those mentioned above.
NRC staff evaluated the laboratory reports for Phase I PSR samples LA-RA01-BJ-016-SSD, LA-RA03-BJ-016-SSD, LA-RA04-BJ-016-SSD, L4-TF05-CR-012-SM, L4-NI01-CR-009-SSD, L4-NI02-CR-012-SSD, L4-NI03-CR-009-SSD, L4-NI04-CR-009-SSD, L4-NI05-CR-010-SSD, L4-NI06-CR-010-SSD, and L4-NI07-CR-011-SSD from reference areas and non-impacted survey units. These samples contained detectable gross alpha and gross beta activity. Samples with gross alpha contained naturally occurring radionuclides based on the gamma spectroscopy analysis. Those with gross beta activity contained either Cs-137, naturally occurring radionuclides or both based on the gamma spectroscopy analysis. No other gamma emitters or hard-to-detect (HTD) radionuclides were identified in the onsite and offsite sediment or soil sample analysis. Confirmatory sampling conducted by Oak Ridge Institute for Science and Education (ORISE) in April 2019 confirmed only the presence of Cs-137 and naturally occurring radioactive material (NORM) in soil samples with no HTD radionuclides above their respective analytical minimum detectable activity.
ADP conducted characterization surveys of the non-impacted survey units, CASA, R16Y, and SEAL on April 28 to May 12, 2023, March 29, 2022, March 8, 2022, and March 10, 2022, respectively. The survey results identified no radionuclide concentrations, other than Cs-137, above the MDC. An additional survey of the CASA conducted from November 6-23, 2024, including surface and subsurface sampling found no radionuclide concentrations above the
13 MDC. The characterization surveys supported the deselection of all radionuclides other than Cs-137 for the survey units within this PSR.
The NRC staff has reviewed ADPs justification for selections of the radionuclides of concern and the supporting data. Based on the above considerations, the NRC staff finds ADPs process for selection of Cs-137 as the only radionuclide of concern for soils adequate because it is consistent with MARSSIM guidance and satisfies the requirements of 10 CFR 20.1501(a) and 10 CFR 50.83.
4.2.6.2 Background Reference Areas ADP chose to apply the Scenario B, i.e., indistinguishable from background, methodology using the guidance in MARSSIM and NUREG-1505, Chapter 13, Demonstrating Indistinguishability from Background. BRAs are used to establish any differences in concentration between the reference area and the survey unit. MARSSIM, Section 4.5, recommends BRAs have similar physical, chemical, geological, radiological, and biological characteristics as the survey units being evaluated. The CREC site exhibited considerable physical and chemical variability being located adjacent to Crystal River Units 1 and 2 (coal power facilities) and surrounded by a varied physical landscape including tidal flats, creeks, wetlands, beachy areas, and woodlands as well as both paved and unpaved access roads. The 618 acres identified in this PSR were inland in the area surrounding the Controlled Area. ADP selected four reference areas.
Reference Area 01 (RA-01) and Reference Area 02 (RA-02) were OLAs located approximately 2.5 miles (4 km) northeast of the CR3 Containment Building and bounded on all sides by privately owned land. Reference Area 03 (RA-03) and Reference Area 04 (RA-04) were OLAs located approximately 2.3 miles (3.7 km) east of the CR3 Containment Building and bounded by State Park Land on all sides. All reference areas consisted of wetlands, woodlands, and unpaved access roads. SER Figure 2 shows the location of the four Phase II PSR BRAs as well as ORISE BRAs from the Phase I PSR.
14 Figure 2. Phase I PSR ORISE and Phase II PSR Background Reference Areas NUREG-1505 provides guidance on the methods used to demonstrate indistinguishability from background including (1) assessing the background variability using the Kruskal-Wallis (KW) test; (2) determining a concentration of radioactivity that is IFB; (3) performing the Wilcoxon Rank Sum (WRS) test; and (4) performing the Quantile test if the survey unit passes the WRS test to determine the presence or absence of elevated measurements. Table 13, BRA Sample Results of Attachment 13 summarized the individual background sample data. ADP completed an initial comparison between the four reference areas to determine whether the BRA dataset could be combined for subsequent comparison to the survey unit. ADP stated that the individual and median values shown in Attachment 13, Figure 7, CR3 BRA Individual Value (pCi/g) Plot were relatively consistent and that the full BRA dataset represented a spatially uniform background distribution. ADP evaluated the percentile values in Figure 8, CR3 Subsets with Medians (pCi/g), which showed generally consistent central tendencies and trends. NRC staff noted that ADP incorrectly recorded Sample Number 11 in RA-03 in Table 13 as 0,142. Based on staff calculations, the maximum, mean, and standard deviation for RA-03 and the combined mean and standard deviation were slightly higher than those in Table 13.
However, ADP used the correct value (0.142 pCi/g) for the BTV determination in Table 14, ProUCL Results for CR3 Combined Data.
In Section 10.4, Kruskal Wallis Test of Attachment 13, ADP indicated that the KW test was used to evaluate whether there were statistically significant differences in radiation activity distributions across the four BRA subsets. ADP stated, The p-value for the comparison was 0.575. Since this p-value is greater than the type I error rate (0.05), the null hypothesis is not
15 rejected, indicating no statistically significant difference between the medians of the four subsets. This result reinforces the conclusion that the subsets are comparable and that the full BRA dataset can be treated as a consistent and unified background reference. However, ADP provided insufficient details on how the test was conducted. Therefore, NRC staff could not verify the p-value. Instead, to evaluate the variability between ADPs four background reference areas, NRC staff conducted an independent KW test using Visual Sample Plan (VSP) which generated a K statistic that was less than the critical value. This indicated that there was no significant variability in the background data. Staff notes, in general, that this level of variation in BRA data does not justify employing Scenario B. However, failing the KW test does not preclude the use of Scenario B.
To determine the concentration that was IFB, ADP conducted an analysis of the BRA combined data using the ProUCL statistical software and selected the 95% Upper Percentile Limit (UPL) based on the Chebyshev inequality as the BTV. ADP used the BTV as the comparison point for individual sample results and population medians. ADP provided minimal explanation for the selection of the 95% Chebyshev UPL which equates to a general, worst-case bounding value.
The ProUCL results included other more conservative nonparametric upper limits for background threshold values. Staff evaluated the impact of these more conservative nonparametric limits for BTV on both the WRS and the Quantile test, i.e., the test that determines indistinguishability from background. The evaluation indicated that the application of the most restrictive option (at the 95% confidence) impacted the outcome of neither the WRS nor the Quantile test.
To evaluate the Cs-137 sample data for the four reference areas and the survey units, NRC staff generated a box and whiskers plot, shown in Figure 3, that shows the randomized sampling Cs-137 concentration for the BRAs (combined), R16Y, SEAL, CASA, and the NIAs (combined). The individual data points outside the whiskers represented outliers as determined by an Excel statistical package. ADP noted no anomalies or quality control issues associated with these sample results that would justify excluding these data points from the data analysis.
Figure 3 demonstrated that the BRAs do not have the same radiological characteristics as the R16Y, SEAL, and CASA survey units while they do have similar radiological characteristics to NIA-01, NIA-02, NIA-03, NIA-04, NIA-05, and NIA-06 combined which could be explained by the disturbance of the soil in the survey units verses BRAs.
16 Figure 3. Box and Whiskers Plot of Cs-137 Concentrations for the BRAs and Survey Units.
ADP supplemented the Phase II PSR BRA analyses with evaluations of nearby fallout in 3. Table 1, Estimates of Potential Cs-137 Concentrations in Soils near CR3 by Latitude and Assumed Depth of Distribution, of Attachment 13 listed values of 0.52 to 0.68 pCi/g for a depth of 0 - 5 cm and 0.09 to 0.11 pCi/g for a depth of 0 - 30 cm. Surface samples taken from 0 - 5 cm depth in undisturbed soil had significantly higher concentrations than those taken from disturbed soils. Based on an NRC review of the survey unit and BRA maps, the R16Y, SEAL, CASA, and NIAs appeared to be partially or completely cleared of trees and other forest vegetation indicating that the areas were disturbed during their history. This may account for some of the differences in Cs-137 concentration between the undisturbed BRAs and the disturbed survey units. Staff review of the highest sample results for all survey units (impacted and non-impacted) shows the sample locations to be from forested areas which give some support to this assumption.
In October 2004, the Navy conducted a comprehensive study of background and fallout radionuclide concentrations. The study found an average concentration of 0.5 pCi/g (0.31 pCi/g decayed) Cs-137 at the Kings Bay Naval Base, approximately 150 miles from CR3. The Phase I PSR BRAs (combined) had average and standard deviation values of 0.074 pCi/g and 0.039 pCi/g, respectively, with a 95th and 99th percentile of 0.132 pCi/g and 0.196 pCi/g, respectively.
These data were based on judgmental sampling with results less than the MDC being set to the MDC. Phase I PSR non-impacted survey units had an average Cs-137 concentration of 0.072 pCi/g. An ORISE confirmatory survey conducted April 8-12, 2019, to support the Phase I PSR established a BTV of 0.332 pCi/g Cs-137 (ProUCL 95% Chebyshev UPL), a mean of 0.084 pCi/g and a standard deviation of 0.055 pCi/g, respectively. The REMP observed that Cs-137 tends to concentrate on vegetation. While CR3 has provided regional data for background, the most representative background Cs-137 concentrations are from the CREC site. The average,
17 95th percentile, and 99th percentile data from the Phase 1 PSR supported a lower BTV than the 95% Chebyshev UPL.
In summary, staff find the sampling approach for the BRAs to be consistent with MARSSIM guidance. Whereas the background reference areas appear to differ in radiological characteristics from the impacted survey units and the CASA, the results are within the range of backgrounds for the other non-impacted survey units. Although not optimal, the combined BRA Cs-137 concentration is not significantly above other onsite background studies, and staff find no evidence to indicate that the BRAs were impacted by site operations based on a review of the HSA. While the staff disagree with the selection of the 95% Chebyshev UPL as the BTV, there is no impact on the survey unit analysis when applying more conservative BTVs such as the 95th percentile. The NRC finds that ADPs BRA analysis is adequate to demonstrate compliance with 10 CFR 20.1402 and 10 CFR 20.1501(a) as pertaining to background reference areas.
4.2.6.3 Scanning Surveys The purpose of scanning during FSS is to identify locations within the survey unit that exceed the investigation levels established in the PSR and which may indicate small areas of significant increases in the residual radioactivity present. As a part of the Scenario B process, the survey unit is evaluated to identify areas of elevated activity. These locations are intended to be marked and receive additional investigations to determine the concentration, area, and extent of the radiological contamination. MARSSIM Table 5.9, Recommended Survey Coverage for Structures and Land Areas, specifies the recommended survey coverage for impacted OLAs.
MARSSIM does not specify a minimum scan coverage requirement for Class 3 survey units; instead, the guidance states that judgmental scans should be performed in areas that are most likely to indicate potential radiological contamination. The PSR did not explicitly state the procedure for determining scan coverage; however, the total area scanned for R16Y, SEAL, and NIA-01 through NIA-06 (combined) was included in the discussion of surface scans in Attachments 3, 5, and 2, respectively. The scan coverage for non-impacted and impacted areas is summarized in Table 3 and Table 5 of the SER, respectively. ADP identified scanning locations on maps along with the gamma scanning locations, and random, judgmental and investigative sample locations.
Sections 6.4, Measurement Methods, 6.5, Radiation Detection Instrumentation, and Table 6.3 Radiation Detectors with Applications to Gamma Surveys, of MARSSIM provide guidance on radiation detection instrumentation and FSS scanning methods. ADP conducted gamma walkover surveys in both non-impacted and impacted survey units except for the CASA which contained significant quantities of NORM that interfered with scanning performance. ADP performed gamma scans on accessible land surfaces using a Ludlum model 2241 survey meter coupled to a Ludlum model 44-10, 5.1 centimeter (cm) by 5.1 cm (2 inch (in) by 2 in) thallium-doped sodium iodide (NaI) scintillation detector following a serpentine pattern with three passes across each square meter. ADP performed the gamma scans at a speed of 50 cm (20 in) or less per second with a probe distance of approximately 7.5 cm (3 in) from the surface.
Surveyors responded to audible differences and periodically paused to observe instrument response and establish the range of measurements which were reported in the radiological survey reports for the survey units. Due to non-radiological safety concerns the technicians focused on audible differences in measurements. Attachments 2, 3 and 5 included survey area maps with the random sample locations and scanning areas for NIA-01 through NIA-06, R16Y and SEAL survey units, respectively. Although not required, ADP conducted scanning in the non-impacted survey units except for the CASA where the high NORM in the coal ash
18 generated typical background dose rate between 50-60 µR/hr which interfered with effective scanning. NRC staff found the approach to conducting scanning surveys acceptable.
MARSSIM, Section 5.5.3, recommends that investigation levels for Class 3 areas be established to identify areas of elevated activity that may indicate the presence of significant residual radioactivity. ADP established the alarm set-point, i.e., investigation level, for scan surveys at the instrument minimum detectable count rate (MDCR) plus ambient background.
When measurements above this value were observed, ADP conducted an investigation and collected samples where appropriate. NRC staff summarized in Table 2 the average background measurements for the R16Y, SEAL, and non-impacted areas (combined). ADP determined the average background radiation for each survey unit from multiple measurements within the areas (e.g., one measurement at each corner and one at the center of the survey unit).
Table 2. Background Measurement Range for Open Land Survey Units Survey Unit Minimum
Background
(cpm)
Maximum
Background
(cpm)
Average
Background
(cpm)
MDCRsur veyor (cpm)1 Investigation Level (cpm)2 R16Y 3,629 5,810 4,720 1039 5759 SEAL Not provided Not provided 7,036 1268 8304 NIA (combined) 3,419 14,346 6,0393 1175 7214 1 The MDCRsurveyor (also referred to as MDCR) is calculated by NRC staff.
2 The investigation level, calculated by NRC staff, is the sum of the MDCRsurveyor and the average background.
3 The standard deviation of the background for the NIA combined area was 3,115 cpm.
The MDCR is calculated using Equation 6.3 of NUREG 1507, Minimum Detectable Concentrations with Typical Radiation Survey for Instruments for Various Contaminants and Field Conditions, Revision 1 (ADAMS Accession No. ML003676046).
Where MDCR is the minimum detectable count rate for the surveyor, si is the minimum detectable number of net source counts in the observation interval, d is the index of sensitivity, bi is the background counts in the observation interval, and i is the observation interval based on the scan speed and extent of the contamination. ADP did not include the investigation levels.
During the audit, NRC staff requested that ADP provide either the MDCRs or the data used in the calculation of these values. The Phase II PSR, Rev. 1 included a d value of 1.38 in the R16Y and SEAL FSSRs; however, ADP provided no values for the interval (i) and the surveyor efficiency (p). In the absence of these data, NRC staff calculated an MDCRsurveyor for R16Y, SEAL, and NIA (combined) assuming an observation interval of 1 second, a surveyor efficiency of 0.5, and a d value of 1.38 to obtain an estimated investigation level with results reported in Table 2. NRC staff noted that the investigation levels are within the expected background level of 9750 cpm (in a 10 uR/hr field) reported for the Ludlum Model 44-10 by the instrument vendor.
In addition to investigative sampling, ADP conducted judgmental/biased sampling in low lying areas exhibiting slightly elevated levels of detection but not exceeding the MDCR. An NRC staff
19 review of the data summaries found that investigative samples were collected in Survey Units NIA-05, R16Y, and SEAL. For R16Y, only one of four investigative samples contained a Cs-137 concentration above the detection limit at 0.0369 pCi/g. These samples also contained NORM which likely contributed to the elevated activity. For SEAL, no investigative samples contained Cs-137 concentration above the detection limit; however, the samples did contain NORM. In the case of NIA-05, ADP collected investigative samples around NIA-05-04 and NIA-05-021-B, which had Cs-137 concentrations of 0.174 pCi/g and 0.152 pCi/g, respectively. Because these values are less than the maximum BRA Cs-137 concentration of 0.239 pCi/g and well below the NUREG-1757, Volume 2, Revision 2 screening value of 11 pCi/g for Cs-137, NRC staff did not consider these results safety significant. Furthermore, NRC staff noted that the mean Cs-137 concentration for NIA-05 was 0.0323 pCi/g which is less than the average value (0.08 pCi/g) for all BRAs.
NRC staff find that areas of elevated measurements above ambient background were identified during scanning and investigated in both non-impacted and impacted survey units. NRC staff find that ADPs approach to scanning surveys as discussed in Attachments 2, 3 and 5 is adequate to demonstrate compliance with 10 CFR 20.1402, 10 CFR 20.1501(a) and 10 CFR 50.83 as pertaining to scanning surveys.
4.2.6.4 Number of Samples and Sample Location for Survey Units MARSSIM, Section 5.5.2, Survey Design and NUREG-1757, Volume 2, Appendix A, Implementing the MARSSIM Approach for Conducting Final Radiological Surveys, discuss how to determine the number of sampling and measurement locations (sample size - N) necessary to ensure sufficient data for statistical analysis, such that there is reasonable assurance that the survey unit will pass the requirements for release. MARSSIM Table 5.3, Values of N/2 for Use with the Wilcoxon Rank Sum Test, determines the minimum number of survey samples for chosen DQOs (Type I (, release of a survey unit containing residual radioactivity above the release criterion, or false negative) and Type II (, failure to release a survey unit when the residual radioactivity is below the release criterion, or false positive) decision error rates) assuming a calculated relative shift. The relative shift (/) for the survey unit is defined as the shift (), which is the upper bound of the gray region (UBGR) minus the Lower Bound of the Gray Region (LBGR) divided by the standard deviation () of the data set used for survey design. The sample number may be determined as a part of the FSS planning process.
Determining the number of random samples to be collected when applying IFB typically involves the determination of the number of measurements in the reference area and the number of measurements in the survey unit simultaneously. ADP opted to determine the sample number for the BRAs and survey units separately since the surveys were planned and implemented at different times. ADP calculated the required sample numbers for the BRA based on the results from the Phase I PSR BRAs. ADP assigned the UBGR as the discrimination limit (1.6 pCi/g) based on professional judgment and set the LBGR equal to the estimated mean from prior surveys (0.8 pCi/g). ADP equated to the coefficient of variation times the mean (0.3*0.8=0.024). A Type 1 and Type 2 error rate of 0.05 were applied for determining sample number.
= 1.6 0.8 0.024
= 33
20 Based on the Type 1 and Type 2 errors and the relative shift, MARSSIM Table 5.3 identified the required number of samples in the reference areas as nine. ADP increased the sample number to fifteen per reference area consistent with the recommendation in NUREG-1505, Chapter 13, for 10-20 samples in each BRA when using four BRAs.
For impacted survey units, ADP applied the BTV of 0.23 pCi/g, the average from the characterization survey, and the standard deviation from the characterization survey to calculate the relative shift for R16Y and SEAL. ADP subsequently determined that the required sample number for both Class 3 survey units was nine. However, ADP collected seventeen random samples in R16Y and fifteen random samples in SEAL. They opted to use the combined BRAs, applied for comparison to the survey units which collectively had a total of 60 samples.
To verify the correct sample number, NRC staff conducted an independent analysis using the VSP software by applying the same assumptions to both BRAs and survey areas. The LBGR (3), UBGR (i.e., the median of the collective background data), and standard deviation of the collective background data were selected as zero, 0.08 pCi/g, and 0.034 pCi/g, respectively.
Applying these values, the VSP software determined the required sample number for both the reference areas and survey units to be fourteen. Although the sample number determined by NRC staff was greater than the nine determined by ADP, ADP collected a minimum of fifteen samples in each of the BRAs and survey units.
ADPs survey team referenced the locations with the use of a global positioning system.
Attachments 2, 3, 4, and 5 contained maps of the survey units on which measurement and sample locations were recorded. ADP established a reference grid to facilitate scanning as well as establishing measurement and sampling locations. Trained and qualified personnel obtained samples from randomly generated locations determined by VSP software.
Based on the above considerations, the NRC staff finds that ADPs number of samples and sample locations for the PSR OLA survey units is consistent with the applicable MARSSIM and NUREG-1757 guidance. Therefore, the sampling methodology for the Class 3 OLA survey units is acceptable to, in pertinent part, meet the regulatory requirements for survey in 10 CFR 20.1501(a) and 10 CFR 50.83(a)(3).
4.2.7 Non-impacted Survey Unit Results MARSSIM, Section 2.5.2, indicates that, for non-impacted land, all the information necessary to demonstrate compliance is available from existing sources and no statistical tests are necessary. Additionally, Table 2.2 of MARSSIM, Recommended Conditions for Demonstrating Compliance Based on Survey Unit Classification for a Final Status Survey, requires no elevated measurement comparison, no sampling and/or direct measurements and no scanning to be performed in non-impacted areas. Nevertheless, ADP conducted a comprehensive characterization survey that included scanning, random sampling and biased sampling to support existing information from the HSA. Table 3 summarizes the scanning coverage and sampling conducted as a part of the characterization surveys for the NIA survey units and the CASA characterization survey.
21 Table 3. Non-impacted Survey Unit Sample Numbers Survey Unit Scan Coverage Random Samples Judgmental/
Investigative Samples HTD analysis QC Recount QC Split NIA-01 4,469 m2 (1.1%)
17 0/0 2
2 2
NIA-02 6,366 m2 (1.6%)
17 0/0 2
2 2
NIA-03 6,021 m2 (1.5%)
17 1/0 2
2 2
NIA-04 3,940 m2 (1.2%)
16 1/0 2
2 2
NIA-05 4,543 m2 (1.2%)
17 4/10 2
2 2
NIA-06 4,702 m2 (1.3%)
17 0/0 2
2 2
CASA Surface Soil No scanning 15 0/0 2
2 2
CASA 0-3 ft 15 2
2 2
CASA 3-6 ft 15 2
2 2
CASA 6-9 ft 15 2
2 2
ADP scanned a total of 11% of accessible areas within NIA-01 through NIA-06 for a total of 30,041 m2. ADP investigated locations with an audible response above the investigation level (MDCR plus ambient background) or localized background, by conducting investigative sampling. ADP also collected judgmental samples where material may concentrate such as low-lying areas and areas exhibiting slightly elevated levels of detection.
The DQO stated that all Cs-137 sample concentrations in non-impacted areas were consistent with regional background data and no detection of plant ROCs occurred. Based on the discussion above on background reference areas, ADP considered a Cs-137 concentration less than 0.23 pCi/g IFB. For the purposes of determining statistical quantities, ADP collected random surface samples in the NIA areas and the CASA. Since it was initially thought that residual radioactivity was deposited in the CASA, ADP also collected subsurface composite samples at the following depths: 0-3 feet, 3-6 feet, and 6-9 feet. Table 4 summarizes the sampling results for non-impacted areas. ADP sent two samples from each survey unit to an offsite laboratory for analysis of the full suite of radionuclides.
22 Table 4. Surface and Subsurface Cs-137 Results by Survey Unit1, 2 Survey Unit Maximum Mean Median Standard Deviation NIA-01 0.0579 0.00716 0.00301 0.0201 NIA-02 0.0918 0.00587 0.00209 0.0291 NIA-03 0.0972 0.0158 0.00486 0.0371 NIA-04 0.0618 0.0185 0.0199 0.0260 NIA-05 0.174 0.0323 0.0160 0.0493 NIA-06 0.0317 0.00247 0.000903 0.0170 CASA (Surface) 0.0138
-0.0120
-0.0102 0.0181 CASA (0-3 ft) 0.0228
-0.0288
-0.0253 0.0315 CASA (3-6 ft) 0.0128
-0.0224
-0.0253 0.0214 CASA (6-9 ft) 0.0317
-0.0173
-0.0195 0.0285 1 Characterization surveys for NIA-01 through NIA-06, and the November 2024 survey for the CASA.
2 Subsurface sampling occurred in only the CASA.
With the exception of NORM and Cs-137, the analyses detected neither gamma-emitting nor HTD radionuclides above the a posteriori MDC in either the surface or subsurface samples.
Based on a review of onsite and offsite laboratory surface and subsurface sample results, NRC staff found that all Cs-137 concentrations were less than the BTV of 0.23 pCi/g determined by ADP. Additionally, the mean and median concentrations for the non-impacted survey units were less than the 95th percentile of the BRAs combined (0.128 pCi/g). ADP has demonstrated that the Cs-137 concentration in the NIAs is less than background. Furthermore, the offsite analysis of the full suite of radionuclides identified no other gamma emitting or HTD radionuclides above the a posteriori MDC.
Based on the surveys described above and the HSA, the NRC staff finds that ADPs designation of NIA-01, NIA-02, NIA-03, NIA-04, NIA-05, NIA-06, and the CASA were consistent with the definition of non-impacted areas in 10 CFR 50.2. Staff have also determined that mean and median concentrations for Survey Units NIA-01, NIA-02, NIA-03, NIA-04, NIA-05, NIA-06, and the CASA are less than that in the reference areas; therefore, no dose will be assigned for these survey units.
4.2.8 Impacted Survey Unit Final Survey Results and Reporting Attachments 3 and 5 documented the FSSRs for R16Y and SEAL, respectively, as supplemented by Attachments 1, 6, and 10. Collectively these attachments included an overview of the FSS results with a description of the survey unit and sample locations, scanned area, number of samples taken, measured concentrations and a posteriori MDCs, judgmental and investigative sample data, discussion of anomalous data in excess of investigation levels, and a statistical evaluation of the measured concentrations in relation to the BRAs. The FSSR also discussed quality assurance and offsite sampling results.
23 Staff summarized in Table 5 the scanning survey coverage, and the number of samples, both random, judgmental and quality control (QC), that were collected and analyzed during the characterization (CHAR) and FSS for Class 3 areas. ADP analyzed all survey unit samples for gamma-emitting radionuclides onsite with two FSS samples per survey unit sent offsite to GEL Laboratories, LLC (GEL) for analysis of the full suite of radionuclides. Table 3-2 of Attachments 3 and 5 listed the ROCs and average GEL MDC levels for offsite sample analysis. The reported MDC for Cs-137 was 0.0348 pCi/g for R16Y and 0.0288 pCi/g for SEAL, which was below the ADP designated BTV of 0.23 pCi/g. Table 3-3 of Attachments 3 and 5 provided a priori MDCs for Co-60, Cs-137, Eu-152, and Eu-154 associated with the onsite analyses. The Cs-137 MDC was 0.045 pCi/g, which was less than the 0.23 pCi/g BTV. Both the onsite and offsite a priori MDC are also below the 95th percentile BRA value of 0.128 pCi/g. Other onsite and offsite MDCs were below the NUREG-1757, Volume 2 screening levels for soil except for tritium.
However, a posteriori tritium MDCs for all offsite samples were less than the tritium screening level.
Table 5. Survey Unit Characterization and Final Status Survey Sample Numbers Survey Unit Scan Coverage Random Samples Judgmental/
Investigative Samples HTD analysis QC Recount QC Split R16Y 1,808 m2 (11%)
17 0/2 2
2 2
SEAL 1,257 m2 (46%)
15 0/4 2
2 2
R16Y (CHAR) 6 2/0 1
1 1
SEAL (CHAR) 6 0
1 1
1 Release surveys performed following the removal of radioactive material storage containers for both R16Y and SEAL provided results consistent with the baseline surveys for both areas. ADP conducted initial characterization surveys, documented in Attachments 3 and 5, on March 8, 2022, and March 10, 2022, in R16Y and SEAL, respectively. Attachment 10 described the overall characterization effort of the impacted OLAs. The results indicated a maximum Cs-137 residual radioactivity concentration of 0.029 pCi/g in R16Y with no other positively detected radionuclides, and a maximum Cs-137 residual radioactivity concentration in SEAL of 0.0173 pCi/g with no other positively detected radionuclides.
ADP completed an FSS in R16Y in October 2023, and an FSS in SEAL in November 2024.
These areas required no remediation prior to conducting the FSS. ADP designed and implemented the survey based on DQOs defined in Attachments 3 and 5 for these survey units.
The null hypothesis required that the R16Y and SEAL area Cs-137 concentration population mean (µSA) be less than or equal to the background mean concentration with no other detectable plant-related gamma-emitting radionuclides. NRC staff summarized in Table 6 the statistical results for Cs-137 residual radioactivity concentrations in each survey unit.
24 Table 6. Impacted Surface Soil Cs-137 Results by Survey Unit1 Survey Unit Maximum Mean Median Standard Deviation R16Y 0.0963 0.00123
-0.000923 0.0279 SEAL 0.0229 0.00132 0.00350 0.0120 1 Reported data were based on the final status survey results.
All samples for the R16Y and SEAL survey units were less than the BTV of 0.23 pCi/g for Cs-137 while other gamma emitting and HTDs were less than the a posteriori MDC.
Furthermore, the maximum Cs-137 values were less than the 95th percentile of the BRAs (0.128 pCi/g).
To evaluate the survey units under Scenario B, NUREG-1505, Chapter 6, 7, and 13 and MARSSIM recommend that the WRS test and the Quantile test be completed. Attachment 1 contained an individual value plot and a Quantile plot comparing the BRA measurements with the survey unit measurements for both R16Y and SEAL. A visual comparison of central tendencies and overall distribution in Attachment 1, Figure 16, BRA Comparison with R16Y Cs-137 Levels and Figure 19, BRA Comparison with SEAL Cs-137 Levels showed that the survey unit concentrations were lower than the background. ADP provided a Quantile plot for R16Y and SEAL in Attachment 1, Figure 17, BRA and R16Y Quantile Plot and Figure 19, BRA and SEAL Quantile Plot demonstrating that R16Y and SEAL were statistically lower than background levels with no measurements exceeding the 95th percentile (0.128 pCi/g). Based on the visual results and the p-value derived for each survey unit, ADP concluded that R16Y and SEAL were indistinguishable from background.
While Attachment 1 stated that the WRS test and Quantile test were completed, ADP did not provide the detailed analyses. NRC staff completed an independent assessment of the data using the VSP software which included a WRS test and the Quantile Test. The evaluation indicated that R16Y and SEAL were IFB and the survey units were clean based on the failure to reject the null hypothesis. The retrospective power curve indicated that the survey had sufficient statistical power to support this conclusion.
NRC staff also evaluated the maximum Cs-137 sample measurements for R16Y and SEAL against the Cs-137 screening values for surface soil from NUREG-1757, Volume 2, Revision 2, Appendix H of 11 pCi/g. Applying the screening level, the dose assigned to R16Y and SEAL surveys units assuming the maximum concentration would be 0.22 and 0.052 mrem/y, respectively. Using the mean concentration, these values would drop to 0.0028 and 0.003 mrem/y for R16Y and SEAL, respectively. NUREG-1757, Chapter 6 recommends a performance based ALARA evaluation based on the actual site conditions and cost incurred.
The concentrations in the impacted survey units are less than the background and indicate no presence of plant-related residual radioactivity. Therefore, given that no dose is assigned where survey units are IFB, no further efforts to reduce dose and risk to the public are required thus meeting the ALARA requirement.
For the reasons discussed in the NRC evaluation of the ADP Class 3 OLA survey units, the NRC staff find that the FSS release records for these survey units demonstrate residual radioactivity in the R16Y and SEAL are less than BRA concentrations. The null hypothesis was not rejected indicating the survey unit is IFB. Therefore, no dose assignment is required for these survey units. With the data presented in the FSSRs, staff have reasonable assurance that the survey units comply with the 25 mrem/y unrestricted release criteria and ALARA
25 requirements specified in 10 CFR 20.1402 and that surveys have been conducted consistent with 10 CFR 20.1501(a).
4.3 Quality Assurance (QA)/Quality Control (QC)
MARSSIM, Chapter 9, Quality Assurance and Quality Control provides recommendations on evaluation of data collected and analyzed from surveys to ensure that radiation surveys produce results that are of the type and quality needed to support the intended purpose of demonstrating compliance with release criteria. The data assessment involves data verification, data validation, and Data Quality Assessment (DQA).
ADP stated that surveys were designed using the seven step DQO process in MARSSIM. ADP followed QA/QC procedures in accordance with the site-specific Quality Assurance Program Plan. Upon completion of each survey, ADP performed a DQA to determine whether the survey and sampling were consistent with the DQOs and satisfied the survey objectives. ADP identified no deficiencies or problems associated with implementation of the FSSs. ADP calibrated onsite laboratory instruments with National Institute of Standards and Technology (NIST) traceable multiline sources. In addition, ADP performed daily instrument source response checks, energy and efficiency calibration checks, background checks, and replicate volumetric measurements prior to use.
NRC staff spot checked reported survey results against onsite and offsite laboratory reports and identified a single discrepancy for Sample Number NIA-03-006. The reported value in for Co-60 was -5.01 pCi/g, whereas the Co-60 concentration on the onsite laboratory report was -5.01E-3 pCi/g. The error had no impact on the release of the survey unit as the requirement for being less than MDC was still met. The NRC staff verified the values in Table 6-5, Basic Statistical Quantities for NIA-03 in Attachment 2 were correct.
ADP conducted sample recounts and split sampling in each non-impacted and impacted survey unit to evaluate data quality in accordance with site procedures. Any QA/QC issues noted had no impact on the overall confidence of the results or the conclusions from those survey results.
The NRC staff verified that the frequency of recount and split samples taken in the nine survey units exceeded the ten percent specified in the sampling plan and the Phase II PSR. NRC staff found the QC analysis of the split and recount samples for the NIA-01, NIA-02, NIA-03, NIA-04, R16Y, SEAL, and the surface and subsurface CASA QC samples met the acceptance criteria.
Two split samples, NIA-05-016 and NIA-06-005, failed the QC evaluation for Cs-137 but passed for other gamma emitting radionuclides. In both cases, the GEL result showed low levels of Cs-137 while the onsite Cs-137 concentration was less than zero. According to MARSSIM Section 7.2, replicate measurements with results at or near the detection limit should not be used to assess precision, since the associated measurement uncertainty exceeds the desired level of precision. In this case, one of the two sample measurements for Cs-137 was below the detection limit, making it an unsuitable basis for comparison. However, considering this guidance and the acceptable performance of other gamma-emitting radionuclides with concentrations above the detection limit, the NRC staff determined that the QC evaluation for samples NIA-05-016 and NIA-06-005 meets quality control requirements. Overall, the review of the QC data identified no QC issues that would impact the confidence of the results or the conclusion of the survey for the Phase II PSR survey units.
Based on the considerations above, NRC staff find the licensees methodology for assessing QC measurement samples for the non-impacted and Class 3 survey units, as demonstrated in
26 the release surveys for these survey units, is acceptable. The QC approach for the Phase II PSR open land survey units is of sufficient type, quality, and quantity to demonstrate compliance with 10 CFR 50.83 and the radiological criteria for unrestricted release specified in 10 CFR 20.1402.
4.4 Isolation and Controls Evaluation Isolation and controls (I&Cs) are established to prevent the spread of contamination from areas of the site under active decommissioning to those previously released. Contamination of cleaned areas from residual radioactivity in impacted areas can occur as a result of human, equipment, and environmental transport, including both surface and subsurface migration pathways. NUREG-1757, Volume 2, Revision 2, Section G.3.5 recommends measures be taken to avoid recontamination of clean areas and RG 1.179 recommends FSS plans describe access control procedures to avoid recontamination of clean areas. ADP established I&C measures for post FSS survey units and non-impacted areas in accordance with site procedures including the prevention of use, storage, and movement of radioactive material through previously released areas. Attachment 1, Figure 15, Haul Paths of Radiological Materials, showed truck exit and rail line paths and the haul path to the loading areas do not transverse R16Y, SEAL, CASA, or the NIAs. No demolition or waste processing materials with loose residual radioactivity traverse the PSR survey units. However, containerized/packaged radioactive waste, surveyed and acceptable for transport to a low-level waste disposal site, may traverse areas as they are moved and loaded for rail transport. Surveys of roadways are conducted routinely to verify the absence of radioactive contamination.
The FSS for R16Y occurred in October 2023 and for the SEAL in November 2024. MARSSIM, Section 4.4, Classify Areas by Contamination Potential, identifies buffer zones around Class 1 areas as an example of a Class 3 area. The southeast portion of NIA-04 and the southwest corner of NIA-05 are adjacent to DISC-02 through DISC-10, which are Class 1 and Class 2 survey units. While it is prudent to establish Class 3 buffer areas around Class 1 areas, ADP argued during the audit that the residual radioactivity from the Discharge Canal was underwater and not readily dispersible. NRC staff expressed concern about the potential for recontamination of non-impacted areas should remediation of the Discharge Canal occur. ADP agreed to revise their procedure to add controls specific to cross-contamination if remediation in the discharge canal is required. Primarily, this will be to conduct remediation efforts from the south side of the Discharge Canal to prevent the spread of contamination to NIA-04 and NIA-05.
The NRC staff evaluated Attachments 1, 3, and 5 to review ADPs proposed strategy for preventing surface migration of contaminated materials to Phase II PSR survey units. NRC staff found ADPs planned implementation of I&Cs to be consistent with 10 CFR 20.1501. Therefore, the planned I&Cs provide reasonable assurance that released survey units within this PSR will not be recontaminated.
4.5 Groundwater Staff reviewed Attachment 1 and Attachment 10 for information on groundwater in the outlying areas of NIA-01 through NIA-06, CASA, R16Y, and SEAL. Staff also reviewed GHS Environmental (2017, CR3 Groundwater Flow Study Summary Report, ADAMS Accession No. ML23160A299 or ML24090A007) for flow patterns across the CREC site and recent Annual Radiological Environmental Operating Reports (AREORs) for data on radioactivity in wells along flow pathways from onsite to PSR areas.
27 In the PSR submittal, the licensee also provided two attachments on water quality and water use to support their position that groundwater was not usable as a source of drinking water, irrigation, or other waterborne pathways in the PSR areas. Attachment 8 addressed the State of Florida well permitting regulations and results of SEAWAT water quality modeling of the mixing of sea water and freshwater for the berm area between the intake and discharge canals. addressed the basis for insignificant groundwater contamination based on an analysis of a less likely but plausible resident farmer scenario using RESRAD. Staff, however, determined that an NRC evaluation of information on the water quality and water use in the PSR areas was not required based on information provided by the licensee that soil and groundwater media contained no plant-related radioactivity; see SER section 4.2 for radioactivity in soils and SER section 4.5.1 for radioactivity in groundwater.
For the safety decision, staff evaluated two issues related to groundwater in the PSR areas.
The staff review first evaluated the groundwater flow patterns from the power block area into the PSR areas to evaluate the possible need for revisions to the effluent monitoring program as described in SER section 4.5.1. The staff next evaluated the potential presence of existing residual radioactivity (i.e., plant-related radionuclides) in the groundwater system in SER section 4.5.2.
4.5.1 Groundwater Flow Patterns and Potential Offsite Effluent Discharge Staff evaluated groundwater flow patterns to determine if the environmental monitoring program and ODCM still meet the 10 CFR 50.83(a)(1)(iv) requirements for offsite effluents for the proposed site boundary. To meet this regulation, NUREG-1757 Volume 2 Appendix K guidance suggests that an assessment be provided for all radionuclide migration pathways from onsite to the proposed PSR areas, including the groundwater system. The regulation requires that offsite effluent discharge monitoring must remain active from the period of operation through completion of decommissioning that, for the latter, covers the possibility of releases to the groundwater occurring or being identified during any soil disturbing and building excavation activities of decommissioning.
On page 42 of Attachment 1, ADP stated that all PSR areas are outside any pathways for migration of radioactive material from decommissioning activities including surface and ground water. In support of their groundwater pathways conclusion, ADP cited Attachment 12, which contained an analysis of the January and February 2024 groundwater sampling events that indicated laboratory results above the critical level (Lc), but below the MDC, were false positives. Staff noted that Attachment 12 does not contain any information about groundwater flow pathways from the remaining onsite area (e.g., protected area) to the proposed PSR areas.
Furthermore, staff noted that most of the wells in those sampling events are not at locations that reflect groundwater flow from onsite (i.e., likely source area for contamination) to offsite PSR areas, i.e., those wells are upstream of the berm.
To determine if the ODCM still meets the requirements, staff compared the site-wide groundwater pathways to the new proposed site boundary. Whereas no groundwater contamination plumes currently exist based on data in the Annual Radioactive Effluent Reports, staff must also consider the possibility of contamination being first identified or caused by the subsurface disturbing activities associated with decommissioning. ADP provided general information in GHS Environmental (2017) on the sites hydrogeology and groundwater flow patterns under low, average, and high tidal conditions. On a site-wide scale, groundwater generally flows to the west-southwest towards the coastal swamps and gulf. At a smaller scale in the vicinity of the berm under low and average tidal conditions, flow pathways deflect around
28 the subsurface structure that was constructed below the Reactor and Auxiliary Buildings within the berm (see the schematic cross-section in Figure 1 in Haley & Aldrich, 20241). Figures 5 through 9 of GHS Environmental (2017) illustrated the buffeting caused by the subsurface concrete structure that deflects groundwater to the north and south around the structure.
According to Figures 6 and 7 of GHS Environmental (2017), the flow divergence around the subsurface structure suggested that groundwater enters proposed PSR areas which would be considered offsite if the PSR is approved.
For the deflection to the north, staff noted that the groundwater flows into the southwest corner of NIA-05 and subsequently into the southeast corner of NIA-04 before likely seeping into the discharge canal because of the influence of the large-scale south-southwest groundwater flow pattern. Onsite monitoring wells CR3-1S and CR3-10 are located near the proposed site boundary along this pathway. For the deflection to the south of the subsurface structure, staff noted that the groundwater from the eastern part of onsite decommissioning areas would flow into NIA-06. Whereas some of the groundwater subsequently may seep into the intake canal, a significant portion of the groundwater continues south-southwestward across the survey unit before seeping into the coastal swamps. Onsite monitoring wells CR3-3S and CR3-4 are located near the proposed site boundary along this pathway.
Staff noted that, prior to approval of the Phase I PSR, offsite groundwater only flowed directly to the gulf based on staffs interpretation of information provided in GHS Environmental (2017).
After the Phase I PSR approval in 2020 and the modification of the site boundary, offsite groundwater only flowed to the coastal swamps with the primary component flowing between and into the canals. Considering risk information for offsite groundwater releases into the gulf or into the coastal swamps, staff noted that exposure pathway factors would be extremely small.
For the Phase II PSR, the situation arises where onsite groundwater flows into the land areas of NIA-06, NIA-05, and NIA-04. Staff noted that the ODCM does not include a calculation method for offsite effluent discharge in the groundwater system. However, wells in the REMP happen to be located to potentially detect offsite migration of a contaminant plume. If monitoring wells detect residual radioactivity during decommissioning, ADP would be required to add a dose calculation method to the ODCM following NUREG-1301 (Offsite Dose Calculation Manual Guidance: Standard Radiological Effluent Controls for Pressurized Water Reactors, ADAMS Accession No. ML091050061) and RG 1.21 (Measurement, Evaluating, and Reporting Radioactive, Material in Liquid and Gaseous Effluents and Solid Waste, ADAMS Accession No. ML21139A224).
In summary, staff evaluated offsite groundwater migration pathways to determine if the environmental monitoring program and ODCM still met the requirements in 10 CFR 50.83(a)(1)(iv) for offsite effluents at the proposed site boundary. Staff noted that groundwater flow pathways under average and low tidal conditions exhibit migration pathways to the south and north from the eastern side of the berm area that flow offsite into the PSR areas. Monitoring wells CR3-1, CR3-3S, CR3-3D, CR3-4, and CR3-10 would detect offsite migration into the PSR areas since they are located on the northeast and southeast corners of the berm. ADP included all these wells in REMP and thus they would continue to be monitored based on the current ODCM. The staff concludes that the requirement in 10 CFR 50.83(a)(1)(iv) for tracking any possible offsite groundwater effluent will continue to be 1 Haley & Aldrich, 2024, Development of Site-Specific Values for RESRAD Hydrogeological and Hydrological Parameters ADP CR3 Decommissioning Project, Crystal River, Florida, dated January 31, 2024, ML24090A007. Cited in Attachment 9 of Phase II PSR submittal (ML25170A029).
29 met because ADP has included wells in the REMP that are positioned to detect radionuclide migration approaching the new site boundary.
4.5.2 Residual Radioactivity in Groundwater Staff considered four aspects in their evaluation of the possible presence of plant-related radionuclides in groundwater of the PSR areas: (i) radionuclide results from groundwater samples associated with the PSR areas; (ii) radionuclide results from REMP wells along the flow pathways into PSR areas adjacent to the berm; (iii) non-impacted designation or nature of activities for impacted areas of the PSR; and (iv) IFB assessment for all PSR areas.
For the first aspect, ADP provided information on measurements of existing groundwater contamination in Attachment 12. ADP provided the results of the January 2024 sampling event for several wells across the site, including three wells in or near the CASA (wells TWI-3, TWI-2R, and CCRW-29) and one well along the flow path into NIA-06 (well CR3-4). ADP obtained samples from six wells. However, staff noted that two of the wells are located west of the berm and thus are not relevant to the PSR based on west-southwestward groundwater flow direction. The laboratory analyses covered the initial suite of 13 radionuclides potentially present at the site which staff noted as consistent with the initial suite of radionuclides reviewed by staff in SER section 4.2.5.1 for ROCs for the soil media. For the four relevant wells, the radionuclides above the critical level (Lc) included Sr-90, Eu-152, and C-14. Staff described the issue in item 2 of the NRC Audit Report dated May 17, 2025 (ADAMS Accession No. ML25156A235). Because three results from the four wells would be statistically unlikely to all be false positives, ADP undertook the routine approach of implementing a follow-up sampling event in February 2024 to address the possibility. For this second sampling event, ADP reported two values above the value associated with the Lc at two of the three wells associated with PSR areas. The radionuclides exceeding Lc included Sr-90 and Ni-63. The specific radionuclides above Lc were from different wells compared to the first sampling event.
Staff confirmed that ADP reported and interpreted laboratory analyses consistent with guidance in Chapter 20 of the Multi-Agency Radiological Laboratory Analytical Protocols Manual (MARLAP, NUREG-1576). The analytical results in question fell between the value associated with blank samples (i.e., Lc) but below the MDC a posteriori value. Because several of the analytical results fell in the range between the Lc and MDC but were close to the Lc, ADP considered the possibility that those results were false positives. Chapter 20 of MARLAP indicated that the Lc is associated with the measurement system signal noise of blank samples.
Results above the value associated with the Lc statistically represent a detection of a radionuclide. MARLAP defined the MDC as an estimate of the true concentration of analyte required to give a specified high probability that the measured response will be greater than the Lc; typically, a probability of 95 percent is used. As described in MARLAP, the range between the Lc and MDC indicated that the radionuclides were statistically detected but that the value of the concentration is unreliable.
ADPs support for the false positive hypothesis in Attachment 12 cited several considerations, including that (i) the averages from the two data sets from January and February 2024 were below the value associated with the Lc, (ii) radionuclide results above the Lc in the first data set were below the Lc in the second data set, and (iii) all results above the Lc value were much closer to the Lc than to the MDC value. In addition, ADP suggested that tritium values, as an indicator radionuclide for residual radioactivity, were below the Lc in all cases. Because of the reasons mentioned above, staff finds that the analyses of groundwater samples support ADPs
30 conclusion that there are no plant-related radionuclides in the groundwater of the PSR areas based on the well data.
For the second aspect, historical measurements of wells along flow pathways into PSR areas reflect further on the possibility of groundwater contamination in PSR areas. Staff identified four monitoring well locations (CR3-1, CR3-3S/D, CR3-4, and CR3-10) that are part of the REMP groundwater monitoring program as documented in the ODCM and reported in AREORs. The ODCM specified quarterly tritium and gamma spectroscopy analyses of groundwater samples; gamma spectroscopy results presented in AREOR tables included K-40, Co-60, Cs-134, and Cs-137 for the onsite CR3 series wells. Staff considered the radioactivity measured in the REMP as indicator radionuclides for the suite of 13 radionuclides identified for the site in SER section 4.2.5.1. Staff noted that historical measurements from the four wells listed above have not indicated the presence of residual radioactivity, thus assuring it unlikely that contamination has migrated offsite across the proposed site boundary into the PSR areas NIA-04, NIA-05, and NIA-06.
For the third aspect, staff considered both the non-impacted designation of some PSR areas or the nature of activities for the other PSR areas (i.e., impacted areas PSR areas) using information that ADP provided in the PSR and HSA (Attachment 6). Staff provided a detailed review of the site activities, scanning, and sampling for the different PSR areas in SER section 4.2.5. For the R16Y and SEAL survey units, which were designated as impacted, the HSA indicated that site activities occurred there (i.e., storage during Refueling Outage #16) but that there was no record of any spills, leaks, or uncontrolled releases of radioactive material. In addition, release surveys in 2009 and 2013 for the impacted survey units indicated no plant-related radioactivity in the surficial soils. For the CASA survey unit, ADP initially identified the CASA as impacted in the 2016 HSA (Attachment 4) due to the disposal of an unknown quantity of potentially contaminated sediments from a lagoon west of the berm at an unknown location in the CASA. In the 2025 History of settling pond radioactivity levels and work activity Rev 5 Attachment K to Attachment 4, ADP identified historical records and procedures that suggested no contaminated lagoon sediments were disposed of in the CASA survey unit. ADP designated all other PSR survey units (i.e., NIA-01 through NIA-06) as non-impacted based on information in the HSA which staff found acceptable in SER section 4.2.5.
For the fourth aspect, staff considered radionuclide levels both in surface soils of PSR areas and in wells along flow paths from onsite areas to PSR areas. The staffs evaluation of soil sample analyses in SER sections 4.2.6 and 4.2.7 found that the PSR area results were indistinguishable from the reference area background samples. In addition, scan surveys at eight of the nine partial site areas found no indications of residual radioactivity. ADP indicated that scanning was not practical for the ninth area, i.e., the CASA. For groundwater, staff noted in SER section 4.5.1 that several monitoring wells were located along flow pathways from onsite locations into PSR areas. Wells CR3-3S and CR3-4 are located along the flow path into NIA-
- 06. CR3-1 and CR3-10 are located along flow pathways into NIA-05. Analytical results from these wells did not exhibit any detections of residual radioactivity based on data in Attachment 12 and in recent AREORs. Because no residual radioactivity was identified in the surface soils across all PSR areas nor was any detected in monitoring wells along flow pathways into the PSR areas, staff considers it unlikely that groundwater in these areas is contaminated due to site activities.
In summary, staff found with reasonable assurance that the groundwater in the PSR areas is not likely contaminated with residual radioactivity because (i) measurements of groundwater radioactivity in wells located in the PSR areas indicate that no plant-related radionuclides were
31 present; (ii) for wells in the groundwater flow pathways from onsite and into PSR areas, historical measurements from monitoring wells from the REMP have not exhibited contamination of indicator radionuclides; (iii) the combination of the HSA designation of non-impacted areas (i.e., no site activities) and the lack of identified spills, leaks, or releases for impacted areas; and (iv) the IFB result of surface soils analyses for all PSR areas and no residual radioactivity in groundwater samples along flow paths from the new onsite area (berm area) to the proposed offsite areas.
5.
NRC INSPECTIONS AND CONFIRMATORY SURVEYS NRC staff reviewed the following seven NRC inspection reports, which were issued between January 2022 and December 2024, because they support the validity of the FSS program implementation: 05000302/2022001 (ADAMS Accession No. ML22116A183),
05000302/2022002 (ADAMS Accession No. ML22209A130), 05000302/2022003 (ADAMS Accession No. ML23144A034), 05000302/2023002 (ADAMS Accession No. ML24108A031),
5000302/2023003 (ADAMS Accession No. ML23058A253), 05000302/2024001 (ADAMS Accession No. ML24261C022), and 05000302/2024002 (ADAMS Accession No. ML25071A202) dated May 3, 2022, August 9, 2022, March 22, 2023, May 25, 2023, April 17, 2024, September 23, 2024, and March 13, 2025, respectively. This period covered the time when characterization and FSSs were conducted. The inspectors performed plant tours to assess field conditions and decommissioning activities, interviewed personnel, and reviewed records pertaining to areas of review. During these inspections the following areas were evaluated:
Design changes and modifications reviews
The corrective action program implementation
Decommissioning performance and status reviews
Fire protection
Occupational radiation exposure
Final status survey
Effluent monitoring
Solid waste management and transportation of radioactive materials
Safety conscious work environment implementation
Financial assurance During 2022, the inspectors reviewed activities and documentation associated with radioactive effluent control and site REMP to assess the effectiveness of site radiological programs.
Additionally, they evaluated changes made to the ODCM, Process Control Program, and radioactive waste system design and operation. The inspectors reviewed radioactive gaseous and liquid effluent release permits, licensee audits, 2022 groundwater monitoring reports and procedures associated with entering events into the records system file as required by 10 CFR 50.75(g). In 2024, the inspectors toured selected environmental monitoring stations to determine the adequacy of instrumentation location. They also observed groundwater sampling and collection of air monitor samples. The inspectors conducted walkdowns of the effluent treatment system modified in the prior inspection period and reviewed under the 10 CFR 50.59 process applicability determination. They verified that the effluent treatment system was adequately described and modified to treat radioactive effluents for batch releases. The long-term groundwater monitoring report, the annual radioactive effluent release report, and the annual radiological environmental operating report demonstrated that calculated doses were below regulatory dose criteria listed in 10 CFR 50, Appendix I. Inspectors verified that effluent sampling equipment were checked, calibrated, and maintained as specified in the ODCM and
32 that sampling stations were accessible as described in the ODCM. No violations associated with the effluent sampling program were identified.
During the period 2022-2024, the inspectors verified that radiation work permits and ALARA work plans were implemented effectively to limit worker exposure, and occupational dose was appropriate for the scope of the radiological activities performed. Inspectors found that ADPs Radiation Protection staff effectively controlled work activities. Several inspection reports noted individuals within the radiation protection program, including those conducting surveys, were trained and qualified to meet the requirements within the site licensing basis. Instrument program evaluations noted that radiation instrumentation was properly calibrated, and source checked.
In 2022, inspectors reviewed ADPs plans for implementing FSSs, the procedure for isolating and controlling areas for FSSs, the plans for characterizing the East Settling Pond, the HSA, the training and qualification requirements for staff that plan, review, and implement FSSs, and condition reports related to FSSs. In addition, through the support of ORISE, the inspection also included confirmatory surveys of the East Settling Pond area. The inspectors determined that the development, review, and approval of the survey plan for the East Settling Pond adequately followed the procedures developed for FSSs and verified the adequacy of the processing and archiving of the soil samples. Review of the HSA indicated that the radiological classification of the East Settling Pond as a Class 3 area was adequate. The inspectors also found that the East Settling Pond area had been adequately isolated and controlled since completion of the FSS of that area. An at-risk FSS following piping removal was observed by inspectors in 2024; however, the specific location was not identified in the inspection report.
The inspectors determined that the instruments were appropriately source checked, and adequate chain of custody controls occurred. The inspectors identified no violations related to the performance of these observed final status surveys.
In 2022 and 2023, the inspectors reviewed the 10 CFR 50.59 screenings and evaluations performed during the respective time periods. The inspectors determined that selected changes under 10 CFR 50.59 did not require prior NRC approval and safety reviews were performed for design changes and modifications in accordance with applicable regulatory requirements, license conditions and the Decommissioning Safety Analysis Report. The 10 CFR 50.59 safety evaluation program and associated training of reviewers were found to be consistent with regulatory requirements.
The NRC Staff determined that no confirmatory surveys were necessary for the non-impacted and Class 3 areas defined in the Phase II PSR. While a confirmatory survey of the East Settling Pond area was conducted, it occurred after the removal of the sediment that was relocated to the CASA. The ORISE survey did not include areas specific to the PSR.
In summary, NRC inspections corroborated that radiological surveys were conducted in accordance with site procedures by trained and qualified staff using appropriately calibrated and source checked instrumentation. Additionally, they provide verification that I&Cs have been implemented following FSS for those areas evaluated.
6.
ENVIRONMENTAL REVIEW Pursuant to 10 CFR Part 51, an environmental assessment (ADAMS Accession Number ML25240B598) has been prepared for this action and a finding of no significant impact (FONSI)
33 was issued. The EA and FONSI were published in the Federal Register on September 26, 2025 (90 FR 46661).
7.
EPA-NRC MEMORANDUM OF UNDERSTANDING (MOU)
The NRC staff reviewed the PSR application and concluded that any radioactive material present is not within the scope of the MOU. The NRC staff reached this conclusion because the levels of radioactivity identified are not above background levels in soils and there are no indications that plant-related radionuclides are present in the groundwater. Therefore, the NRC staff determined that consultation with EPA is not required under the MOU.
8.
PUBLIC COMMENTS The NRC staff held a public meeting near CR3 on July 23, 2025. The NRC received no comments from the members of the public in attendance. An on-line comment was submitted on August 1, 2025 (ADAMS Accession No. ML25218A166). The comment related to the future use of the land that ADP requests to release from the license. The commenter stated Crystal River Unit 3 should be released to allow for property modifications required and all relevant documentation retained for the property owners and improvements required for future construction and sale.
9.
STATE CONSULTATION In accordance with the Commissions regulations, the NRC notified the State of Florida about issuance of the license amendment on August 19, 2025 (ADAMS Accession No. ML25261A016). The NRC requested comments by September 10, 2025. The State of Florida provided no comments.
10.
CONCLUSIONS ADP requested approval for release of property described in Section 4.0 of this safety evaluation, which is currently part of the CR3 site, for unrestricted use. Based on an evaluation of ADPs PSR application, the NRC staff concludes that the licensees submittal has adequately:
(1) Assessed the property to be released; (2) Evaluated the effect of releasing the property; (3) Justified the survey units NIA-01, NIA-02, NIA-03, NIA-04, NIA-05, NIA-06, and CASA are non-impacted areas; (4) Justified that radionuclide concentrations in the SEAL and R16Y impacted survey units are IFB; and (5) Addressed the effect of releasing the property for unrestricted release.
Staff conclude that there is no dose associated with the PSR areas because the areas were justified as non-impacted or soils were IFB and there is no indication of plant-related radionuclides in the groundwater.
The NRC staff concludes that ADPs request meets the requirements of 10 CFR 50.83, as well as that: (1) there is reasonable assurance that the health and safety of the public will not be endangered; and (2) the release will not be inimical to the common defense and security.
Therefore, the NRC approves the unrestricted release of 618 acres comprised of survey units
34 NIA-01, NIA-02, NIA-03, NIA-04, NIA-05, NIA-06, CASA, R16Y, and SEAL, as described in the partial site release application, from Facility Operating License No. DPR-72.