ML20009E611

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Restoration Project Final Status Survey Report - Phase 3, FSS Release Record - December 2019
ML20009E611
Person / Time
Site: Zion  File:ZionSolutions icon.png
Issue date: 12/30/2019
From: Wojtkowiak D
ZionSolutions
To:
Office of Nuclear Material Safety and Safeguards
Shared Package
ML20009E643 List:
References
ZS-2019-0114
Download: ML20009E611 (62)
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-H ZION STATION RESTORATION PROJECT FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 DECEMBER 2019

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 2

Summary of Changes in this Revision: Initial Revision

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 3

Prepared By: D Wojtkowiak Date:

2019/12/30 C/LT Radiological Engineer Reviewed By: R Massengill Date:

2019/12/30 C/LT Radiological Engineer Approved By: D. E. Williams, Jr.

Date:

2019/12/30 C/LT Manager

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 4

TABLE OF CONTENTS 1

Introduction........................................................................................................................... 10 1.1 Executive Summary....................................................................................................... 10 1.2 Phased Submittal Approach........................................................................................... 14 2

Final Status Survey Program Overview................................................................................ 15 2.1 Survey Planning............................................................................................................. 17 2.2 Survey Design................................................................................................................ 22 2.3 Survey Implementation.................................................................................................. 24 2.4 Survey Data Assessment................................................................................................ 25 2.5 Quality Assurance and Quality Control Measures......................................................... 26 3

Site Information.................................................................................................................... 27 3.1 Site Description.............................................................................................................. 27 3.2 Survey Unit Description................................................................................................. 28 3.3 Summary of Historical Radiological Data..................................................................... 36 3.4 Conditions at the Time of Final Status Survey.............................................................. 38 3.5 Identification of Potential Contaminants........................................................................ 38 3.6 Radiological Release Criteria......................................................................................... 39 4

Final Status Survey Protocol................................................................................................. 40 4.1 Data Quality Objectives................................................................................................. 40 4.2 Survey Unit Designation and Classification.................................................................. 45 4.3 Background Determination............................................................................................ 45 4.4 Final Status Survey Sample Plans.................................................................................. 45 4.5 Survey Design................................................................................................................ 45 4.5.1 Determination of Number of Data Points............................................................... 45 4.5.2 Sample Locations.................................................................................................... 47 4.6 Instrumentation............................................................................................................... 47 4.6.1 Detector Efficiencies............................................................................................... 47 4.6.2 Detector Sensitivities.............................................................................................. 47 4.6.3 Instrument Maintenance and Control...................................................................... 48 4.6.4 Instrument Calibration............................................................................................ 48 4.7 Survey Methodology...................................................................................................... 49

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4.7.1 Scan Surveys........................................................................................................... 49 4.7.2 Soil Sampling.......................................................................................................... 49 4.8 Quality Control Surveys................................................................................................. 49 5

Survey Findings.................................................................................................................... 50 5.1 Survey Data Conversion................................................................................................. 51 5.2 Survey Data Verification and Validation....................................................................... 54 5.3 Anomalous Data/Elevated Scan Results and Investigation........................................... 55 5.4 Evaluation of Number of Sample/Measurement Locations in Survey Units................. 57 5.5 Comparison of Findings with Derived Concentration Guideline Levels....................... 57 5.6 Description of ALARA to Achieve Final Activity Levels............................................. 59 5.7 NRC/Independent Verification Team Findings............................................................. 59 6

Summary............................................................................................................................... 59 7

References............................................................................................................................. 60 8

Appendices............................................................................................................................ 61

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LIST OF TABLES Table 1-1, Phase 3 Survey Units................................................................................................... 11 Table 2-1, Base Case and Operational DCGLs for Surface Soils(1)............................................. 20 Table 2-2, Base Case and Operational DCGLs for Subsurface Soils(1)........................................ 20 Table 2-3, Typical Final Status Survey Unit Areas...................................................................... 21 Table 2-4, Dose Significant Radionuclides and Mixture(1)........................................................... 22 Table 4-1, Surrogate Ratios.......................................................................................................... 41 Table 4-2, Number of Surface Soil Samples for FSS................................................................... 46 Table 4-3, Recommended Scan Coverage.................................................................................... 49 Table 5-1, Basic Statistical Properties for FSS of Phase 3 Open Land Survey Units.................. 52 Table 5-2, Mean Base Case SOF and Dose Contribution from Soil............................................ 58 LIST OF FIGURES Figure 1-1, Phase 3 Survey Unit Locations.................................................................................. 13 Figure 2-1, Characterization/License Termination Group Organizational Chart.............................

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LIST OF ACRONYMS AND ABBREVIATIONS ALARA As Low As Reasonably Achievable AMCG Average Member of the Critical Group ASP Alarm Set Point BcDCGL Base Case Derived Concentration Guideline Level BcSOF Base Case Sum of Fractions CAD Computer Aided Design CAP Corrective Action Program C/LT Characterization/License Termination DCGL Derived Concentration Guideline Level ComEd Commonwealth Edison Company DSAR Defueled Safety Analysis Report DQA Data Quality Assessment DQO Data Quality Objective EMC Elevated Measurement Comparison ESCSG EnergySolutions Commercial Services Group ETD Easy-to-Detect FSS Final Status Survey FSSR Final Status Survey Final Report GPS Global Positioning System HSA Historical Site Assessment HTD Hard-to-Detect HPGe High-Purity Germanium IEMA Illinois Environmental Management Agency ISFSI Independent Spent Fuel Storage Installation LBGR Lower Bound of the Gray Region LTP License Termination Plan MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC Minimum Detectable Concentration

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MDCR Minimum Detectable Count Rate NAD North American Datum NaI Sodium Iodide NIST National Institute of Standards and Technology NRC Nuclear Regulatory Commission ODCM Offsite Dose Calculation Manual OpDCGL Operational Derived Concentration Guideline Level OpSOF Operational Sum of Fractions ORISE Oak Ridge Institute for Science and Education PNNL Pacific Northwest National Laboratory PSDAR Post Shutdown Decommissioning Activities Report PWST Primary Water Storage Tank QA Quality Assurance QAPP Quality Assurance Project Plan QC Quality Control RAI Request for Additional Information RCA Radiologically Controlled Area RE Radiological Engineer ROC Radionuclides of Concern SFP Spent Fuel Pool SOF Sum of Fractions SSC Systems, structures and components SST Secondary Storage Tank TEDE Total Effective Dose Equivalent TSD Technical Support Document UBGR Upper Bound of the Gray Region UCL Upper Confidence Level VCC Vertical Concrete Cask VSP Visual Sample Plan

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ZSRP Zion Station Restoration Project ZNPS Zion Nuclear Power Station

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 10 1

Introduction 1.1 Executive Summary The purpose of this Phase 3 Final Status Survey (FSS) Final Report is to provide a summary of the survey results and overall conclusions which demonstrate that the Zion Nuclear Power Station (ZNPS) facility, or portions of the site, meets the 25 mrem/yr release criterion as established in Nuclear Regulatory Commission (NRC) Regulation 10CFR20.1402 Radiological Criteria for Unrestricted Use.

This Phase 3 FSS Final Report focuses on open land area surface and subsurface soils. The FSS results provided herein assess and summarize that any residual radioactivity remaining in the survey units addressed by this Phase 3 Final Report results in a Total Effective Dose Equivalent (TEDE) to an average member of the critical group (AMCG) that does not exceed 25 mrem/yr and, that the residual radioactivity has been reduced to levels that are as low as reasonably achievable (ALARA). The release criterion is translated into site-specific Derived Concentration Guideline Levels (DCGLs) for assessment and summary.

This report documents that FSS activities were performed consistent with the guidance provided in the Zion Station Restoration Project License Termination Plan (LTP)

(Reference 1); NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) (Reference 2); ZS-LT-01, Quality Assurance Project Plan (for Characterization and FSS) (QAPP) (Reference 3); ZS-LT-300-001-001, Final Status Survey Package Development (Reference 4); ZS-LT-300-001-003, Isolation and Control for Final Status Survey (Reference 5); ZS-LT-300-001-004, Final Status Survey Data Assessment (Reference 6); as well as various other station implementing procedures.

This Phase 3 FSS Final Report has been written consistent with the guidance provided in NUREG-1757, Vol. 2, Consolidated Decommissioning Guidance; Characterization, Survey, and Determination of Radiological Criteria (Reference 7); MARSSIM; and the requirements specified in ZS-LT-300-001-005, Final Status Survey Data Reporting (Reference 8).

To facilitate the data management process, Final Status Survey Final Reports (FSSR) incorporate Release Records from the FSS of multiple survey units. Release Records are complete and unambiguous records of the as-left radiological status of each specific survey unit. Each Release Record contains sufficient information necessary to perform an independent review and evaluation of both the survey activities and the final results.

This Phase 3 FSSR specifically addresses forty-one (41) open land area survey units that total approximately 73,546 m2 in area. All forty-one (41) of the open land survey units included in the Phase 3 report are classified as MARSSIM Class 1 survey units. Table 1-1 provides a listing of all the survey units addressed in this report, along with their

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 11 classifications and size. Figure 1-1 depicts the locations of the survey units in relation to the ZNPS site as well as survey unit boundaries.

All FSS activities essential to data quality have been implemented and performed under approved procedures. Trained individuals, using properly calibrated instruments and laboratory equipment, that are sensitive to the Radionuclides of Concern (ROC), performed the FSS of the Phase 3 survey units. The survey data for all Phase 3 survey units demonstrate that the dose (TEDE) from residual radioactivity is less than the maximum annual dose (TEDE) which corresponds to the release criterion for license termination for unrestricted use specified in 10CFR20.1402 and support the release of these areas from the 10CFR50 license. Additionally, the ALARA requirement of 10CFR20.1402 has been satisfied.

Table 1-1, Phase 3 Survey Units Survey Unit (1)

Name Size (m2)

Survey Unit (1)

Name Size (m2) 10201A NE Corner of Restricted Area - Lakeshore 1,554 10220E SE Corner of Exclusion Area -

Inland 1,976 10201B NE Corner of Restricted Area - Lakeshore 1,427 10220F SE Corner of Exclusion Area -

Inland 1,578 10201C NE Corner of Restricted Area - Lakeshore 1,379 10220G SE Corner of Exclusion Area -

Inland 1,674 10201D NE Corner of Restricted Area - Lakeshore 1,472 10220J SE Corner of Exclusion Area -

Inland 2,030 10202A IRSF/Fire Training Area 1,757 10221B South of Protected Area -

Inland 1,855 10202B IRSF/Fire Training Area 1,711 10221E South of Protected Area -

Lakeshore 1,975 10202C IRSF/Fire Training Area 1,696 10221F South of Protected Area -

Lakeshore 1,968 10202D IRSF/Fire Training Area 1,680 10221G South of Protected Area -

Lakeshore 1,956 10203D East Training Area 1,993 10221H South of Protected Area -

Lakeshore 1,994 10203E East Training Area 1,886 12101 WWTF Sludge Drying Bed Area 2,036 10209A Restricted Area South of Gate House 1,966 12102 WWTF 2,024 10209B Restricted Area South of Gate House 1,977 12103 Unit 2 PWST/SST Area 2,034

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 12 Table 1-1 (continued), Phase 3 Survey Units Survey Unit (1)

Name Size (m2)

Survey Unit (1)

Name Size (m2) 10209D Restricted Area South of Gate House 1,586 12112 Unit 1 PWST/SST Area West 1,693 10209E Restricted Area South of Gate House 1,560 12113 Unit 1 PWST/SST Area West 1,658 10210A Restricted Area South of Turbine Building 1,788 12203B Under Service Building and Southeast Yard 1,989 10210B Restricted Area South of Turbine Building 1,913 12203C Under Service Building and Southeast Yard 1,955 10210C Restricted Area South of Turbine Building 1,893 12203D Under Service Building and Southeast Yard 1,635 10211A SE Corner of Restricted Area (Lakeshore) 1,536 12204A Crib House Area 1,943 10211B SE Corner of Restricted Area (Lakeshore) 1,663 12204B Crib House Area 1,971 10220B SE Corner of Exclusion Area - Inland 1,696 12204C Crib House Area 1,994 10220D SE Corner of Exclusion Area - Inland 1,475 (1) All survey units listed had a final classification of Class 1 in accordance with MARSSIM section 4.4 prior to performing FSS This report contains the results of the FSS that pertain to the dose from soil. Based upon the results of groundwater monitoring performed on the ZNPS site since June of 1998 (when both Zion units were placed in a SAFSTOR condition) through the current period of active decommissioning, only minor residual Tritium activity has been identified by groundwater monitoring (as of the date of this Final Report). However, if groundwater contamination is identified at detectable concentrations during decommissioning, the dose will be calculated using the Groundwater Exposure Factors presented in Chapter 6 of the LTP.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 13 Figure 1-1, Phase 3 Survey Unit Locations

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 14 1.2 Phased Submittal Approach To minimize the incorporation of redundant historical assessment and other FSS program information, and to facilitate potential phased releases from the current license, FSSRs are being prepared in a phased approach. ZionSolutions estimates that a total of five (5) FSSRs will be generated and submitted to the NRC during the decommissioning project.

Release of Non-Impacted Open lands On August 27, 2015, ZionSolutions submitted a request (ZS-2015-0134) to release a portion of the ZNPS site from the 10CFR50 licenses (DPR-39 and DPR-48) in accordance with 10CFR50.83, Release of Part of a Power Reactor Facility or Site for Unrestricted Use, and 10CFR100, Reactor Site Criteria. Specifically, a report was generated for the request that addresses the release of eleven (11) non-impacted open land areas from the 10CFR50 licenses. The report contains a summary of the final assessment performed as well as a summary of the characterization surveys performed of these non-impacted survey units. ZionSolutions reviewed and assessed the subject property to ensure that the radiological condition of these land areas will have no adverse impact on the ability of the site, in aggregate, to meet the 10CFR20, Subpart E, Radiological Criteria for License Termination. The submitted report was not captured as a Phased Submittal with a FSSR because the survey units incorporated within the report are classified as non-impacted, and as such, no statistical tests, scan measurements, static measurements, or elevated measurement comparisons are required. The release of the non-impacted areas from the license(s) was approved by the NRC on March 31, 2016.

Phase 1 Final Status Survey Report The Phase 1 FSSR was initially submitted to the NRC on November 1, 2018. The Phase 1 FSSR and the accompanying Release Records addressed the FSS of ten (10) Class 3 open land survey units at Zion. During the review of the Phase 1 FSSR, the NRC identified several quality mistakes which prompted ZionSolutions to withdraw the report until corrections were made. The required corrections were made and the Phase 1 FSSR was resubmitted to the NRC as revision 1, minus two (2) of the ten (10) survey units which were re-subjected to FSS due to the discovery of additional commodities that required removal. On October 9, 2019, the NRC stated that the FSSR was sufficient to demonstrate that the surveys performed of seven (7) of the eight (8) Class 3 open land survey units were acceptable to support release of those survey units for unrestricted release. At the date of this FSSR, the NRC was waiting on a response to a Request for Additional Information (RAI) prior to accepting the Release Record for survey unit 10223.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 15 Phase 2, Part 1 Final Status Survey Report The Phase 2, Part 1 FSSR submitted to the NRC in March of 2019, contained the FSS units that encompassed the basement structures including the Unit 1 and Unit 2 Containments, the Spent Fuel Pool (SFP)/Transfer Canal, the Auxiliary Building, the Crib House/Forebay, the Waste Water Treatment Facility (WWTF) and the Turbine Building. On September 30, 2019, the revised Phase 2, Part 1 FSSR was submitted to the NRC. At the time of this report, the Phase 2, Part 1 FSSR was still undergoing NRC review.

Phase 2, Part 2 Final Status Survey Report The Phase 2, Part 2 FSSR was submitted to the NRC on November 25, 2019, contained the FSS units that encompassed buried pipe.

Phase 4 Final Status Survey Report The Phase 4 FSSR will address the FSS of all remaining open land survey units not addressed in the Phase 3 FSSR. In addition, the Phase 4 FSSR will document the implementation of the compliance equation as required by LTP Chapter 6, section 6.17.

2 Final Status Survey Program Overview The FSS Program consists of the methods used in planning, designing, conducting, and evaluating FSS at the ZNPS site to demonstrate that the premises are suitable for release in accordance with the criteria for decommissioning in Title 10CFR20, Subpart E. Final Status Surveys serve as key elements to demonstrate that the TEDE to an AMCG from residual radioactivity does not exceed 25 mrem/yr, and that all residual radioactivity at the site is reduced to levels that are ALARA.

To implement the FSS Program, ZionSolutions established the Characterization/License Termination (C/LT) Group, within the Radiation Protection division, with sufficient management and technical resources to fulfill project objectives. The C/LT Group is responsible for the safe completion of all surveys related to characterization, FSS, and final site closure. Approved site procedures and detailed technical support documents (TSD) are written to support the FSS process to ensure consistent implementation and adherence to applicable requirements. Figure 2-1 provides an organizational chart of the C/LT Group.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 16 Figure 2-1, Characterization/License Termination Group Organizational Chart Senior Vice President &

General Manager VP -

Environmental Safety & Health Characterization/

LTP Manager Radiological Engineer (LTP Lead)

Radiological Engineer (Characterization/Final Status Survey Lead)

Quality Assurance Manager Radiation Protection Instrumentation & Laboratory Organization Support

- Radiological Instrument Supervisor

-Radiochemist

-Count Room Technician

-Instrument Technician Radiological Engineer Characterization/

FSS Engineer/

Supervisors Characterization/

FSS Technicians

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 17 2.1 Survey Planning Following the cessation of commercial operation, the development and planning phase was initiated in 1999 by the Zion Station Historical Site Assessment (HSA) (Reference 9) and the initiation of the characterization process. The characterization process is iterative and will continue until, in some cases, up to the time of completing FSS. The HSA consisted of a review of site historical records regarding plant incidents, radiological survey documents, and routine and special reports submitted by Exelon Nuclear Generation, LLC (Exelon) to various regulatory agencies. Along with these assessments, interviews with current and past site personnel, reviews of historical site photos, and extensive area inspections were performed to meet the following objectives:

  • Develop the information necessary to support FSS design, including the development of Data Quality Objectives (DQO) and survey instrument performance standards,
  • Develop the initial radiological information to support decommissioning planning, including building decontamination, demolition, and waste disposal,
  • Identify any unique radiological or health and safety issues associated with decommissioning,
  • Identify the potential and known sources of radioactive contamination in systems, surface or subsurface soils, groundwater, and on structures,
  • Divide the ZNPS site into manageable areas or units for survey and classification purposes and,
  • Determine the initial classification of each survey area or unit as non-impacted or impacted. Impacted survey areas or units are Class 1, 2, or 3, as defined in MARSSIM.

Data Quality Objectives are qualitative and quantitative statements derived from the DQO process that clarify technical and quality objectives, define the appropriate type of data, and specify the tolerable levels or potential decision errors used as the basis for establishing the quality and quantity of data required to support inference and decisions. This process, described in MARSSIM and Procedure ZS-LT-300-001-001, Final Status Survey Package Development, is a series of graded planning steps found to be effective in establishing criteria for data quality and guiding the development of FSS Sample Plans. The DQOs developed and implemented during the initial phase of site closure planning directed all data collection efforts.

The DQO approach consists of the following seven steps:

1. State the Problem - This step provides a clear description of the problem, identification of planning team members (especially the decision makers), a conceptual model of the hazard to be investigated, and the estimated resources required to perform the survey. The problem associated with FSS is to determine whether a given survey unit meets the radiological release criterion of 10CFR20.1402.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 18

2. Identify the Decision - This step consists of developing a decision statement based on a principal study question (i.e., the stated problem) and determining alternative actions that may be taken based on the answer to the principle study question. Alternative actions identify the measures to resolve the problem. The decision statement combines the principal study question and alternative actions into an expression of choice among multiple actions. For the FSS, the principal study question is: Does residual radioactive contamination present in the survey unit exceed the established DCGL values? The alternative actions may include no action, investigation, resurvey, remediation, and reclassification.
3. Identify Inputs to the Decision - The information required depends on the type of media under consideration (e.g., soil, water, concrete) and whether existing data are sufficient or new data are needed to make the decision. If the decision can based on existing data, then the source(s) will be documented and evaluated to ensure reasonable confidence that the data area acceptable. If new data are needed, then the type of measurement (e.g., scan, direct measurement, and/or sampling) is determined.
4. Define the Study Boundaries - The step includes identification of the target population of interest, the spatial and temporal features of that population, the time frame for collecting the data, practical constraints, and the scale of decision making. In FSS, the target population is the set of samples or direct measurements that constitute an area of interest. The medium of interest is specified during the planning process.

The spatial boundaries include the entire area of interest, including soil depth, area dimensions, contained water bodies, and natural boundaries. Temporal boundaries include activities impacted by time-related events including weather conditions, season, and operation of equipment under different environmental conditions, resource loading, and work schedule.

5. Develop a Decision Rule - The step develops the binary statement that defines a logical process for choosing among alternative actions. The decision rule is a clear statement using the If...then... format and includes action level conditions and the statistical parameter of interest.
6. Specify Tolerable Limits on Decision Errors - This step incorporates hypothesis testing and probabilistic sampling distributions to control the decision errors during data analysis. Hypothesis testing is a process based on the scientific method that compares a baseline condition (the null hypothesis) to an alternative condition (the alternative hypothesis). Hypothesis testing rests on the premise that the null hypothesis is true and that sufficient evidence must be provided to reject it.
7. Optimize the Design for Obtaining Data - The final step in the DQO process leads to the development of an adequate survey design. By using an on-site analytical laboratory, sampling and analysis processes are designed to provide near real-time data assessment during implementation of field activities and FSS. Gamma scans provide information on soil areas that have residual radioactivity greater than background and

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 19 allow appropriate selection of biased sampling and measurement locations. This data will be evaluated and used to refine the scope of field activities to optimize implementation of the FSS design and ensure the DQOs are met.

As stated, the primary objective of the DQO process was to demonstrate that the level of residual radioactivity found in the soils in the land area survey units, including any areas of elevated activity, was equal to or below the site-specific DCGLs that correspond to the 25 mrem/yr release criterion.

The LTP defines surface soil as that contained in a 0.15-m depth from the surface. The LTP defines subsurface as that contained in a 1-m depth of soil from the surface. Site-specific DCGLs were calculated for both the surface and subsurface soils. Based on characterization data and historical information (LTP Chapter 5, section 5.2.3), there are no expectations of encountering a source term geometry that is comprised of a clean surface layer of soil over a contaminated subsurface soil layer. ZionSolutions TSD-14-011, Soil Area Factors (Reference 10) and LTP Chapter 6, section 6.8, provides the exposure scenarios and modeling parameters that were used to calculate the site-specific DCGLs for soils (referred to as Base Case Soil DCGLs).

Each radionuclide-specific Base Case DCGL (BcDCGL) is equivalent to the level of residual radioactivity (above background levels) that could, when considered independently, result in a TEDE of 25 mrem/yr to an AMCG. To ensure that the summation of dose from each source term is 25 mrem/yr or less after all FSS is completed, the BcDCGLs are reduced based on an expected, or a priori, fraction of the 25 mrem/yr dose limit from each source term. These reduced values are designated as Operational DCGLs (LTP Chapter 5, section 5.2.4) and these Operational DCGLs (OpDCGL) are then used as the DCGL for the FSS design of the survey unit (calculation of surrogate DCGLs, investigations levels, etc.). Details of the OpDCGLs derived for each dose component and the basis for the applied a priori dose fractions are provided in ZionSolutions TSD-17-004, Operational Derived Concentration Guideline Levels for Final Status Survey (Reference 11).

Table 2-1 and Table 2-2 provide listings for the surface and subsurface soil BcDCGL and OpDCGL for the main ROC used for the FSS of the Phase 3 open land areas.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 20 Table 2-1, Base Case and Operational DCGLs for Surface Soils(1)

Radionuclide Base Case DCGL Operational DCGL (pCi/g)

(pCi/g)

Co-60 4.26 1.091 Cs-134 6.77 1.733 Cs-137 14.18 3.630 Ni-63 3,572.10 914.458 Sr-90 12.09 3.095 (1) Compiled from Tables 5-5 and 5-7 of LTP, Chapter 5 Table 2-2, Base Case and Operational DCGLs for Subsurface Soils(1)

Radionuclide Base Case DCGL Operational DCGL (pCi/g)

(pCi/g)

Co-60 3.44 0.881 Cs-134 4.44 1.137 Cs-137 7.75 1.984 Ni-63 763.02 195.333 Sr-90 1.66 0.425 (1) Compiled from Tables 5-6 and 5-8 of LTP, Chapter 5 The development of information to support decommissioning planning and execution was accomplished through a review of all known site radiological and environmental records.

Much of this information was consolidated in the HSA, TSD-14-028, Radiological Characterization Report (Reference 12), and in files containing copies of records maintained pursuant to Title 10CFR50.75(g) (1).

An initial objective of site characterization and assessment was to correlate the impact of a radiological event to physical locations on ZNPS site and to provide a means to correlate subsequent survey data. To satisfy these objectives, the entire 331-acre site was divided into survey areas. Survey area size determination was based upon the specific area and the most efficient and practical size needed to bound the lateral and vertical extent of contamination identified in the area. Survey areas that have no reasonable potential for contamination were classified as non-impacted. These areas had no radiological impact from site operations and are identified in the HSA. Survey areas with reasonable potential for contamination were classified as impacted.

Classification, as described in MARSSIM, is the process by which an area or survey unit is described according to its radiological characteristics and potential for residual

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 21 radioactivity. Residual radioactivity could be evenly distributed over a large area, appear as small areas of elevated activity, or a combination of both. In some cases, there may be no residual radioactivity in an area or survey unit. Therefore, the adequacy and effectiveness of the FSS process depends upon properly classified survey units to ensure that areas with the highest potential for contamination receive a higher degree of survey effort.

The classified survey areas established by the HSA were further divided into survey units.

The suggested surface area limits provided in MARSSIM were used to establish the initial set of survey units for the LTP. A survey unit is a portion of a structure or open land area that is surveyed and evaluated as a single entity following FSS. Survey units were delineated to physical areas with similar operational history or similar potential for residual radioactivity to the extent practical. To the extent practical, survey units were established with relatively compact shapes and highly irregular shapes were avoided unless the unusual shape was appropriate for the site operational history or the site topography. For identification, survey units were assigned a five-digit number that could be further modified by a letter for future divisions if needed (e.g.., if the classification changes, then the corresponding survey unit size limitation changes). Physically, survey unit boundaries were determined using commercially available mapping software with coordinates consistent with the Illinois State Plane System North American Datum (NAD) 1983 East.

Table 2-3 provides an outline for classification versus area size for open land survey units consistent with MARSSIM, Table 1.

Table 2-3, Typical Final Status Survey Unit Areas Classification Area Type Suggested Area Class 1 Land Up to 2,000 m2 Class 2 Land 2,000 to 10,000 m2 Class 3 Land No Limit Prior to FSS, each survey units classification was reviewed and verified in accordance with the LTP and its implementing procedures. A classification change to increase the class could be implemented without notification to regulatory authorities. A classification change to decrease the class would be implemented only after accurate assessment and notification to regulatory authorities as detailed in the LTP and its implementing procedures. Typically, reclassification occurs after the evaluation of continuing characterization results or emergent data indicates a more restrictive classification is required. Final classification was performed via the preparation of the FSS Sample Plan.

The Sample Plan reconciles all outstanding characterization data to determine the appropriate survey unit classification.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 22 2.2 Survey Design Final Status Surveys for the ZNPS site are designed following ZionSolutions procedures, the LTP, and MARSSIM guidance. FSS design utilizes the combination of traditional scanning

surveys, systematic sampling protocols and investigative/judgmental methodologies to evaluate survey units relative to the applicable release criteria for open land sample plans.

To aid in the development of an initial suite of potential ROC for the decommissioning of ZNPS, the analytical results of characterization samples collected at the site were reviewed.

In general, the samples associated with these results were collected from within various waste/process streams and sent off site to meet the analysis criteria of 10CFR61, Subparts C and D. This initial suite of potential radionuclides was further refined by the Containment and Auxiliary Building concrete core data analysis. This analysis determined that Co-60, Cs-134, Cs-137, Ni-63, and Sr-90 accounted for 99.5% of all dose in the contaminated concrete mixes. For activated concrete, H-3, Eu-152, and Eu-154, in addition to the five aforementioned radionuclides, accounted for 99% of the dose. Due to the assumption that all activated concrete will be removed and disposed of as waste, the final suite of ROC for all areas outside of the Containments does not include H-3, Eu-152, and Eu-154.

The results of surface and subsurface soil characterization in the impacted area surrounding ZNPS indicate that there was minimal residual radioactivity in soil. Based on the characterization survey results to date, Zion Station Restoration Project (ZSRP) did not anticipate the presence of significant concentrations of soil contamination. In addition, based on process knowledge, minimal contamination was expected in the buried piping abandoned in place. Consequently, due to the absence of any significant source term in soil or in any buried piping, the suite of ROC and radionuclide mixture derived for the Auxiliary Building concrete was considered a reasonably conservative mixture to apply to soils for FSS planning and implementation. The final suite of potential radionuclides and the mixture to be applied to soils is provided in Table 2-4.

Table 2-4, Dose Significant Radionuclides and Mixture(1)

Radionuclide

% of Total Activity (normalized)

Co-60 0.92 Cs-134 0.01 Cs-137 75.32 Ni-63 23.71 Sr-90 0.05 (1) Compiled from Table 5-2 of the LTP

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 23 Characterization results determined that Co-60 and/or Cs-137 would be the primary gamma-emitting ROC for the majority of survey design. All the FSS results provided in this report utilized Cs-137 as the primary ROC. Cs-137 characterization data for the survey units discussed in this report were used to determine the expected variability, number of samples required, and investigation levels for FSS design.

The dose contribution from each ROC was accounted for using the Sum of Fractions (SOF) to ensure that the total dose from all ROC did not exceed the dose criterion. The SOF or unity rule was applied to the data used for the survey planning, and data evaluation and statistical tests for soil sample analyses since multiple radionuclide-specific measurements were performed or the concentrations inferred based on known relationships. The application of the unity rule served to normalize the data to allow for an accurate comparison of the various data measurements to the release criteria. When the unity rule was applied, the DCGLW (used for the nonparametric statistical test) becomes one (1). The soil DCGLs (surface soil and subsurface soil) are directly analogous to the DCGLW as defined in MARSSIM. The use and application of the unity rule was performed in accordance with section 4.3.3 of MARSSIM.

Survey design objectives included a verification of the survey instruments ability to detect the radiation(s) of interest relative to the DCGL. As standard practice to ensure that this objective was consistently met, radiation detection instruments used in FSS were calibrated on a yearly frequency with a National Institute of Standards and Technology (NIST) traceable source in accordance with ZionSolutions procedures. Instruments were response checked before and after each use. Minimum Detectable Count Rates (MDCR) were established and verified prior to FSS. Control and accountability of survey instruments were maintained and documented to assure quality and prevent the loss of data.

Based upon classification, areas were selected and scanned with gamma radiation detection instruments. Information obtained during the survey was automatically logged by the instrument for review and analysis. Sample and scan coordinates were identified using a random sample tool in Visual Sample Plan (VSP), and a survey unit-specific required scan surface area was applied around the sample point. Sample location coordinates were programmed into a Global Positioning System (GPS), then physically located and marked.

Investigational samples were collected at areas of elevated scan readings. All details and instructions were incorporated into the survey area/units FSS Sample Plan.

Surface soil samples were collected to a depth of 0.15-meters below the topsoil surface.

Leaves, rocks, roots, and other objects were excluded as much as possible from the sample.

In Class 1 open land survey units, subsurface soil samples (soil from a depth of greater than 0.15-meters) are collected as part of the survey design. In accordance with section 5.7.1.6.2 of the LTP, a subsurface soil sample is required at 10% of the systematic surface soil sample locations in a Class 1 survey unit with the location(s) selected at random. In addition, if during the performance of FSS, the analysis of a surface soil sample, or the

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 24 results of a surface gamma scan indicated the potential presence of residual radioactivity at a concentration of 75% of the subsurface soil OpDCGL, then a biased subsurface soil sample(s) would be required to the appropriate depth within the area of concern as part of the investigation. This occurred in seven (7) of the forty-one (41) survey units in this Phase 3 FSSR (survey units 10202B, 10203E, 10209A, 10209D, 10209E, 10221B and 12112).

Designated soil samples were sent to an off-site laboratory for Hard-to-Detect (HTD) analysis. Laboratory analysis results were summarized in Release Records and reported as actual calculated results. Sample report summaries within the Release Records included unique sample identification, analytical method, radioisotope, result, uncertainty (two standard deviations), laboratory data qualifiers, units, and required Minimum Detectable Concentration (MDC).

Another consideration of survey design was the use of surrogates. In lieu of analyzing every sample for HTD radionuclides, the development and application of Surrogate Ratio DCGLs as described in MARSSIM, Sect. 4.3.2 was applied to estimate HTD radionuclide concentration in each sample and survey result. Surrogate ratios allow for expedient decision making in characterization, remediation planning, or FSS design.

A surrogate is a mathematical ratio where an Easy-to-Detect (ETD) radionuclide (i.e.,

Cs-137) concentration is related to a HTD radionuclide (i.e., Sr-90) concentration. From the analytical data, a ratio is developed and applied in the survey scheme for samples taken in the area. Details and applications of this method are provided in section 5.2.11 of the LTP.

Some portion of the radioactivity found in the soil samples is typically attributed to fallout or background. Due to the lack of significant activity revealed during background studies, assessments and characterization, it was determined that background subtraction would not be applied during FSS.

2.3 Survey Implementation Final Status Survey implementation of the Phase 3 survey units started in March 29, 2019.

Implementation was the physical process of the FSS Sample Plan execution for a given survey unit. Each Sample Plan was assigned to a Radiological Engineer (RE) for implementation and completion in accordance with ZionSolutions procedures and the QAPP for Characterization and FSS. The tasks included in the implementation were:

  • Verification and validation of personnel training as required by Training Department and Radiation Protection procedures,
  • Monitoring instrument calibration as detailed in ZS-RP-108-000-000, Radiological Instrumentation Program (Reference 13) and ZS-RP-108-004-012, Calibration and Initial Set-Up of the 2350-1 (Reference 14),

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 25

  • Implementation of applicable operating and health and safety procedures,
  • Implementation of isolation of control of the survey unit in accordance with ZS-LT-300-001-003, Isolation and Control for Final Status Survey,
  • Determination of the amount of sampling required to meet DQOs as described in ZS-LT-300-001-001, Final Status Survey Package Development,
  • Determination of sample locations and creation of survey unit maps displaying the locations in accordance with ZS-LT-300-001-001,
  • Proper techniques for collecting and handling FSS samples in accordance with Job Aid LT-JA-004, FSS Sample Collection (Reference 15),
  • Maintaining Quality Assurance/Quality Control requirements (i.e., replicate measurements or samples) in accordance with the QAPP for Characterization and FSS.
  • Sample Chain-of-Custody maintained in accordance with ZS-LT-100-001-004, Sample Media Preparation (Reference 16),
  • Sample submission to approved laboratories in accordance with ZS-WM-131, Chain of Custody Protocol (Reference 17),
  • Application of the DCGLs to sample results in accordance with the Data Quality Assessment (DQA) process as detailed in ZS-LT-300-001-004, Final Status Survey Data Assessment, and
  • Determination of investigation methodology and corrective actions, if applicable.

The FSS implementation and completion process resulted in the generation of field data and analysis data consisting of measurements taken with handheld radiation detecting equipment, observations noted in field logs, and radionuclide specific analysis. Data were stored electronically on the ZionSolutions network.

2.4 Survey Data Assessment Prior to proceeding with data evaluation and assessment, the assigned FSS Engineer ensures consistency between the data quality and the data collection process and the applicable requirements.

The DQA process is an evaluation method used during review of FSS data to ensure the validity of FSS results and demonstrate compliance with the FSS Sample Plan objectives.

A key step in the data assessment process converts all of the survey results to DCGL units.

The individual measurements and sample concentrations are compared to the DCGL for evidence of small areas of elevated activity or results that are statistical outliers. When practical, graphical analyses of survey data was used to depict the spatial correlation of the measurements For the Class 1 open land areas addressed in this final report, the survey data was evaluated using the Sign Test (as described in the LTP). The Sign Test is a one-sample statistical test that compares data directly to the release criteria. Combined with an effective sampling

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 26 scheme, passing the Sign Test satisfies the release criteria. Selection of the Sign Test is prudent and conservative in the assumption that the radionuclides being considered are not present in background or are at levels at a small fraction of the applicable release criteria.

Furthermore, any background contribution (e.g., Cs-137 from global fallout) in the sample increases the likelihood of failing the survey unit, which is conservative. If the release criteria were exceeded or if results indicated the need for additional data points, appropriate further actions were implemented usually through the issue of an investigation as specified in ZS-LT-300-001-001, Final Status Survey Package Development, or through an addendum or redesign of the FSS Sample Plan.

2.5 Quality Assurance and Quality Control Measures Quality assurance and control measures were employed throughout the FSS process to ensure that all decisions were based on data of acceptable quality. Quality assurance and control measures were applied to ensure:

  • The plan was correctly implemented,
  • The DQA process was used to assess results,
  • DQOs were properly defined and derived,
  • All data and samples were collected by individuals with the proper training and in adherence to approved procedures and sample plans,
  • All instruments were properly calibrated,
  • All collected data was validated, recorded, and stored in accordance with approved procedures,
  • All required documents were properly maintained and,
  • Corrective actions were prescribed, implemented and tracked, as necessary.

Independent laboratories used for analysis of the samples collected during FSS maintain Quality Assurance Plans designed for their facility. ZionSolutions reviews these plans, as required by ZS-QA-10, Quality Assurance Project Plan (Reference 18) and the QAPP for Characterization and FSS, prior to selection of a laboratory for FSS sample analysis to ensure standards are acceptable.

The C/LT Group has been audited by the ZionSolutions Quality Assurance (QA) department on a consistent basis throughout the project at ZSRP. The QA audits have scrutinized the LTP, C/LT procedures, Sample Plans, and C/LT records. The responses to the QA audits are captured in the Corrective Action Program (CAP).

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 27 3

Site Information 3.1 Site Description Zion Nuclear Power Station, owned by Exelon, is located in Zion, Illinois, on the west shore of Lake Michigan. The site is approximately 40 miles north of Chicago, Illinois, and 42 miles south of Milwaukee, Wisconsin.

The owner-controlled site consists of approximately 331 acres, and within the owner-controlled area is an approximate 87-acre, fence-enclosed nuclear facility. The center of the community of Zion is approximately 1.6 miles from the plant location on the site.

There are no schools or hospitals within one mile of the site, and no residences are within 2,000 feet of any ZNPS structures.

Westinghouse Electric Corporation, Sargent and Lundy Engineers, and the Commonwealth Edison Company (ComEd) jointly participated in the design and construction of ZNPS.

The plant was comprised of two (2) pressurized water reactors with supporting facilities.

The primary coolant system for each unit employed a four-loop pressurized water reactor nuclear steam supply system housed in a steel-lined, reinforced concrete containment structure. Each unit employed a pressurized water reactor nuclear steam supply system furnished by Westinghouse Electric Corporation, designed for a power output of 3,250 MWt. The equivalent warranted gross and approximate net electrical outputs of the plant were 1085 MWe and 1050 MWe, for Unit 1 and Unit 2, respectively.

ZNPS was previously operated by Commonwealth Edison until it was permanently shut down on February 13, 1998. On March 9, 1998, ComEd certified to the NRC that all fuel assemblies had been permanently removed from both reactors and placed in the Spent Fuel Pool. The NRC acknowledged the certification of permanent cessation of power operation and permanent removal of fuel from the reactor vessels in a letter dated May 4, 1998. In 2000, the license was transferred from ComEd to Exelon. In 2008, the license was transferred to ZionSolutions to coordinate and execute the decommissioning of the site.

The Post Shutdown Decommissioning Activities Report (PSDAR) (Reference 19) was submitted, in accordance with 10CFR50.82(a), in February 2000 and accepted by the NRC.

An amended PSDAR was submitted in March 2008 to accommodate the transfer of the 10CFR50 licenses to ZionSolutions and to revise cost estimates and the decommissioning schedule. The Defueled Safety Analysis Report (DSAR) (Reference 20) was updated in October 2016. An evaluation of the systems, structures, and components (SSCs) was performed to determine the function these systems would perform in a defueled condition.

With the relocation of the spent fuel to the Independent Spent Fuel Storage Installation (ISFSI), the license basis for the majority of the SSCs was changed and only minimal SSCs were needed to support the ongoing active decommissioning. The remaining SSCs needed to support active decommissioning had controls established in the QAPP and the Offsite Dose Calculation Manual (ODCM) (Reference 21).

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 28 On November 2, 2011, site characterization commenced. At the time these surveys were performed, the site-specific ZionSolutions characterization plans and procedures were still under development. Consequently, due to schedule restraints, ZionSolutions contracted the EnergySolutions Commercial Services Group (ESCSG) to perform characterization of the ISFSI location, the Vertical Concrete Cask (VCC) Construction Area, and the pathway for the new rail track. The results of these surveys were validated and integrated into the subsequent site-specific characterization program, which was approved in February 2012.

Initial scheduled site characterization efforts concluded on November 11, 2013.

3.2 Survey Unit Description The following information is a description of each survey unit addressed in this report at the time of FSS from March 29, 2019 until August 24, 2019. During this period, forty-one (41) open land survey units, covering approximately 73,546 m2 (18.17 acres), were evaluated in accordance with the FSS process specified in the LTP.

Survey Unit 10201A Survey unit 10201A, the Northeast Corner of Restricted Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10202A, the south by survey unit 10201B, the east by survey unit 10222, and the north by survey units 10212A and 10212D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. There is a fence running along the east side of the survey unit.

Survey Unit 10201B Survey unit 10201B, the Northeast Corner of Restricted Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey units 10202B and 10202C, the south by survey unit 10201C, the east by survey unit 10222, and the north by survey unit 10201A.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. There is a fence running along the east side of the survey unit.

Survey Unit 10201C Survey Unit 10201C, Northeast Corner of Restricted Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey units 10202C and 10202D; the east by survey unit 10222, the north by survey unit 10201B and the south by survey unit 10201D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 29 Survey Unit 10201D Survey unit 10201D, Northeast Corner of Restricted Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey units 10202D, the east by survey unit 10222, the north by survey unit 10201C and the south by survey unit 12101.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

Survey Unit 10202A Survey unit 10202A, the Interim Radioactive-Waste Storage Facility (IRSF)/Fire Training Area, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10203E, the south by survey unit 10202B, the east by survey unit 10201A, and the north by survey unit 10212D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10202B Survey unit 10202B, the IRSF/Fire Training Area, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10203E, the south by survey unit 10202C, the east by survey units 10201A and 10201B, and the north by survey unit 10202A.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10202C Survey unit 10202C, the IRSF/Fire Training Area, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10203E, the south by survey unit 10202D, the east by survey units 10201B and 10201C, and the north by survey unit 10202B.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10202D Survey unit 10202D, the IRSF/Fire Training Area, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10203E, the south by survey units 10201C, 10201D, 10201E and 12101, the east by survey units 10201C and 10201D, and the north by survey unit 10202C.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 30 Survey Unit 10203D Survey unit 10203D, the East Training Area, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10203C, the south by survey units 10203F and 12201B, the east by survey unit 10203E, and the north by survey unit 10213C.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10203E Survey unit 10203E, the East Training Area, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10203D, the south by survey units 12201B and 12201C, the east by survey units 10202A, 10202B, 10202C and 10202D, and the north by survey unit 10212D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10209A Survey unit 10209A, Restricted Area South of Gate House, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10208D, the east by survey unit 10209B, the north by survey unit 12202E and the south by survey unit 10221A.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10209B Survey unit 10209B, Restricted Area South of Gate House, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10209A, the east by survey unit 10209C, the north by survey unit 12202E and the south by survey units 10221A and 10221B.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10209D Survey unit 10209D, Restricted Area South of Gate House, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10209C, the east by survey unit 10209E, the north by survey unit 12202F and the south by survey unit 10221C.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 31 Survey Unit 10209E Survey unit 10209E, Restricted Area South of Gate House, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10209D, the east by survey unit 10210A, the north by survey unit 12202F and the south by survey units 10221C and 10221D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10210A Survey unit 10210A, Restricted Area South of Turbine Building, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10209E, the east by survey unit 10210B, the north by survey units 12203A and 12202F; and the south by survey unit 10221D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10210B Survey unit 10210B, Restricted Area South of Turbine Building, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10210A, the east by survey unit 10210C, the north by survey units 12203A and 12203B; and the south by survey units 10221D and 10221E.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10210C Survey unit 10210C, Restricted Area South of Turbine Building, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10210B, the east by survey units 10211A and 10211B; the north by survey unit 12203B and the south by survey unit 10221E.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10211A Survey unit 10211A, Southeast Corner of Restricted Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10210C, the east by survey unit 10224, the north by survey units 12203B and 12203C; and the south by survey unit 10211B.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 32 Survey Unit 10211B Survey unit 10211B, Southeast Corner of Restricted Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10210C, the east by survey unit 10224, the north by survey unit 10211A, and the south by survey unit 10221E.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

Survey Unit 10220B Survey unit 10220B, the Southeast Corner of the Exclusion Area - Inland is a Class 1 open land survey unit. It is bounded on the west by survey unit 10219A, the east by survey unit 10220D, the north by survey unit 10218 (ISFSI), and the south by survey unit 10220C.

The topography of the survey unit is mainly flat with a shallow trench along the south section of the survey unit and a wetland area along its west boundary. In the north end of the survey unit is a fenced area, which surrounds the anchor point for a support cable to a nearby communications tower.

Survey Unit 10220D Survey unit 10220D, the Southeast Corner of the Exclusion Area - Inland is a Class 1 open land survey unit. It is bounded on the west by survey unit 10220B, the east by survey unit 10220E, the north by survey unit 10218 (ISFSI), and the south by survey unit 10220C.

The topography of the survey unit is mainly flat with a shallow trench along the south section of the survey unit. In the center of the survey unit is a fenced area, which surrounds the anchor point for a support cable to a nearby communications tower.

Survey Unit 10220E Survey unit 10220E, the Southeast Corner of the Exclusion Area - Inland is a Class 1 open land survey unit. It is bounded on the west by survey unit 10220D, the east by survey unit 10220A, the north by survey unit 10220F, and the south by survey unit 10220C.

The topography of the survey unit is mainly flat with a shallow trench along the south section of the survey unit.

Survey Unit 10220F Survey unit 10220F, the Southeast Corner of the Exclusion Area - Inland is a Class 1 open land survey unit. It is bounded on the west by survey unit 10218 (ISFSI), the east by survey unit 10220A, the north by survey unit 10220G, and the south by survey unit 10220E.

The topography of the survey unit is mainly flat with some small dips and depressions.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 33 Survey Unit 10220G Survey unit 10220G, the SE Corner of Exclusion Area - Inland, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10218A, the south by survey unit 10220F, the east by survey unit 10220A, and the north by survey unit 10221A.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10220J Survey unit 10220J, the SE Corner of Exclusion Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10220I, the south by survey unit 10220C, the east by survey unit 10224, and the north by survey unit 10221H.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 10221B Survey unit 10221B, South of Protected Area - Inland, is a Class 1 open land survey unit.

It is bounded on the west by survey unit 10221A, the east by survey unit 10221C, the north by survey units 10209B and 10209C; and the south by survey units 10220A and 10220H.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A rail spur, with a ballast made up of gravel, runs through the southern half of the survey unit.

Survey Unit 10221E Survey unit 10221E, South of Protected Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10221D, the east by survey unit 10224, the north by survey units 10210B, 10210C and 10211B; and the south by survey unit 10221F.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

Survey Unit 10221F Survey unit 10221F, South of Protected Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10221D, the east by survey unit 10224, the north by survey unit 10221E, and the south by survey unit 10221G.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 34 Survey Unit 10221G Survey unit 10221G, South of Protected Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10221D, the south by survey unit 10221H, the east by survey unit 10224, and the north by survey unit 10221F.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

Survey Unit 10221H Survey unit 10221H, South of Protected Area - Lakeshore, is a Class 1 open land survey unit. It is bounded on the west by survey unit 10221D, the south by survey units 10220I and 10220J, the east by survey unit 10224, and the north by survey unit 10221G.

A railroad spur runs through the center of the survey unit. The rails sit on a raised ballast of rock 5 to 10 meters in width. The topography of the land to the north and south of the railroad spur is mainly flat with some small dips and depressions.

Survey Unit 12101 Survey unit 12101, the Waste Water Treatment Facility (WWTF) Sludge Drying Bed Area is a Class 1 open land survey unit. It is bounded on the west by survey unit 12201E, the south by survey unit 12102, the east by survey unit 10223, and the north by survey units 10201D and 10202D.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. There is a fence running along the east side of the survey unit.

Survey Unit 12102 Survey unit 12102, the WWTF is a Class 1 open land survey unit. It is bounded on the west by survey unit 12201E, the south by survey unit12103, the east by survey unit 10223, and the north by survey unit 12101.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. There is a fence running along the east side of the survey unit.

Survey Unit 12103 Survey unit 12103, the Unit 2 Primary Water Storage Tank (PWST)/Secondary Storage Tank (SST) Area, is a Class 1 open land survey unit. It is bounded on the west by survey units 12205A and 12201E, the south by survey unit 12204A, the east by survey unit 10223, and the north by survey unit 12102.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. There is a fence running along the east side of the survey unit

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 35 Survey Unit 12112 Survey unit 12112, the Unit 1 PWST/SST Area East, is a Class 1 open land survey unit. It is bounded on the west by survey unit 12113, the south by survey unit 10203D, the east by survey unit 10223, and the north by survey unit 12204C.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

Survey Unit 12113 Survey unit 12113, the Unit 1 PWST/SST Area West, is a Class 1 open land survey unit. It is bounded on the west by survey units 12205D and 12205E, the south by survey units12203B and 12203C, the east by survey unit 12112, and the north by survey unit 12204C.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 12203B Survey unit 12203B, the Area Under Service Building and Southeast Yard, is a Class 1 open land survey unit. It is bounded on the west by survey unit 12203A, the east by survey unit 12203C, the south by survey units 10210B, 10210C, and 10211A, and the north by survey units 12205E and 12113.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 12203C Survey unit 12203C, the Area Under Service Building and Southeast Yard is a Class 1 open land survey unit. It is bounded on the west by survey unit 12203B, the south by survey unit 10211A, the east by survey unit12203D, and the north by survey unit 12113.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam.

Survey Unit 12203D Survey unit 12203D, the Area Under Service Building and Southeast Yard, is a Class 1 open land survey unit. It is bounded on the west by survey unit 12203C, the south and east by survey unit 10223, and the north by survey unit 12112.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is mostly loam. A fence runs along the eastern border of the survey unit.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 36 Survey Unit 12204A Survey unit 12204A, Crib House Area, is a Class 1 open land survey unit. It is bounded on the west by survey units 12205A and 12205B; the east by survey unit 10223, the north by survey unit 12103 and the south by survey unit 12204B.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is a mixture of loam and clay. A fence runs along the eastern border of the survey unit.

Survey Unit 12204B Survey unit 12204B, Crib House Area, is a Class 1 open land survey unit. It is bounded on the west by survey units 12205B and 12205C; the east by survey unit 10223, the north by survey unit 12204A and the south by survey unit 12204C.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is a mixture of loam and clay. A fence runs along the eastern border of the survey unit.

Survey Unit 12204C Survey unit 12204C, Crib House Area, is a Class 1 open land survey unit. It is bounded on the west by survey units 12205C and 12205D; the east by survey unit 10223, the north by survey unit 12204B and the south by survey units 12112 and 12113.

The topography of the survey unit is mainly flat with some small dips and depressions.

The soil is a mixture of loam and clay. A fence runs along the eastern border of the survey unit.

3.3 Summary of Historical Radiological Data The site historical radiological data for this Phase 3 FSSR at ZNPS incorporates the results of the HSA issued in 1999 and supplemented in 2006 and includes the initial characterization surveys completed in 2013.

Historical Site Assessment The HSA was a detailed investigation to collect existing information (from the start of ZNPS activities related to radioactive materials or other contaminants) for the site and its surroundings. The HSA focused on historical events and routine operational processes that resulted in contamination of plant systems, onsite buildings, surface and subsurface soils within the Radiologically Controlled Area (RCA). It also addressed support structures, open land areas and subsurface soils outside of the RCA but within the owner-controlled area. The information compiled by the HSA was used to establish initial survey units and their MARSSIM classifications. This information was used as input into the development of site-specific DCGLs, remediation plans and the design of the FSS. The scope of the

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 37 HSA included potential contamination from radioactive materials, hazardous materials, and other regulated materials.

The objectives of the HSA were to:

  • Identify potential, likely, or known sources of radioactive and chemical contaminants based on existing or derived information,
  • Distinguish portions of the site that may need further action from those that pose little or no threat to human health,
  • Provide an assessment of the likelihood of contaminant migration,
  • Provide information useful to subsequent continuing characterization surveys,
  • Provide an initial classification of areas and structures as non-impacted or impacted,
  • Provide a graded initial classification for impacted soils and structures in accordance with MARSSIM guidance and,
  • Delineate initial survey unit boundaries based upon the initial classification.

The survey units established by the HSA were used as initial survey units for characterization. Prior to characterization, survey unit sizes were adjusted in accordance with the guidance provided in MARSSIM section 4.6 for the suggested physical area sizes for survey units for FSS.

Of the forty-one (41) survey units presented in this report, only five (survey units 12101, 12102, 12103, 12112 and 12113) were given an initial classification as Class 1 and six (survey units 12203B, 12203C, 12203D, 12204A, 12204B and 12204C) were given an initial classification as Class 2 by the HSA. Based on process knowledge and historical surveys to date, the remaining thirty (30) survey units were given an initial classification of Class 3. During building demolition in the Spring of 2017, discrete particles of radioactive material were identified during the performance of operational surveys and Radiological Assessments in and around the Class 2 and Class 3 survey units. As a conservative measure in June of 2017, the classification of a majority of the open land survey units located within the 87-acre, fence-enclosed area was increased to Class 1. This action included all survey units addressed in this report that were initially classified as Class 2 or Class 3.

Characterization Surveys Site characterization of the ZNPS was performed in accordance with ZS-LT-02, Characterization Survey Plan (Reference 22). It was developed to provide guidance and direction to the personnel responsible for implementing and executing characterization survey activities. The Characterization Survey Plan worked in conjunction with implementing procedures and survey unit specific survey instructions (sample plans) that were developed to safely and effectively acquire the requisite characterization data.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 38 Characterization data acquired through the execution of the Characterization Survey Plan was used to meet three primary objectives:

  • Provide radiological inputs necessary for the design of FSS,
  • Develop the required inputs for the LTP,
  • Support the evaluation of remediation alternatives and technologies and estimate waste volumes.

The final output of the initial site characterization was TSD-14-028, Radiological Characterization Report. The report concluded that based on the results of the characterization surveys, it was expected that residual plant-derived radioactivity was present in the forty-one (41) survey units addressed by this report.

3.4 Conditions at the Time of Final Status Survey The land areas discussed in this report are open land areas. All above ground structures and commodities were removed and disposed of during decommissioning. Portions of the open land areas specified were excavated to remove buried pipe and commodities.

Excavations created to remove sub-grade commodities were assessed against the OpDCGLs for subsurface soil prior to backfill in accordance with LTP Chapter 5, section 5.7.1.6. All subsurface soil that was identified as exceeding the subsurface soil OpDCGLs was excavated and removed as waste. Excavations were backfilled using overburden that was successfully surveyed against the subsurface soil OpDCGLs or with clean fill brought in from non-radiological off-site sources. Open land survey units were then smoothed and brought to grade using heavy earth-moving machinery. Transit roads consisting of gravel and hard packed dirt were maintained for vehicular traffic.

Prior to FSS, areas ready for survey were isolated and controlled under ZS-LT-300-001-003, Isolation and Control for Final Status Survey. This included posting of the area as well as notifications to site personnel. Permission was obtained from C/LT staff to enter and work in these areas. Posting of the boundaries controlled public access, a routine surveillance program monitored for any inadvertent public access with procedurally defined recovery and reporting protocols in the event of any impact to the final status of these survey units.

3.5 Identification of Potential Contaminants ZionSolutions TSD-11-001, Technical Support Document for Potential Radionuclides of Concern During the Decommissioning of the Zion Station (Reference 23) was prepared and approved in October 2012. The purpose of this document was to establish the basis for an initial suite of potential ROC for the decommissioning. Industry guidance was reviewed as well as the analytical results from the sampling of various media from past plant operations. Based on the elimination of some of the theoretical neutron activation

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 39 products, noble gases and radionuclides with a half-life of less than two years, an initial suite of potential ROC for the decommissioning of the ZNPS was prepared.

The site characterization showed that the radionuclide identified in most of the samples was Cs-137. For all of the characterization samples, the concentrations of Cs-137 were typical of the concentrations determined from off-site locations and fallout as documented by TSD-13-004, Examination of Cs-137 Global Fallout In Soils At Zion Station (Reference 24). Characterization results also identified Co-60 at concentrations greater than MDC at several locations.

Cs-137 deposition resulting from global fallout is thought to be the source of most of the Cs-137 encountered in samples collected in the open lands surrounding ZNPS. Geological deposition, regional concentrations and transport mechanisms are well documented and the subject of numerous publications and studies. However, as a conservative measure, Cs-137 resulting from fallout or background was not subtracted from analytical results for FSS at ZNPS.

In accordance with the LTP, a minimum of 10% of the non-parametric sample population or any sample with a SOF of 0.1 or greater was sent to an off-site laboratory for HTD ROC analysis. This process was done to verify that the surrogate ratios between HTD ROC and the ETD ROC as established in the LTP remains valid and conservative even with changing environmental conditions. For soil samples with positive results for both a HTD ROC and the corresponding surrogate radionuclide, the HTD to surrogate ratio would be derived. If the derived surrogate ratio exceeded the maximum surrogate ratios presented in LTP Chapter 5, Table 5-15, then consideration would be given to using a survey unit specific surrogate ratio after sufficient investigation and consultation with the NRC.

Analyses for HTD radionuclides positively identified Sr-90 and Ni-63 in some samples, but the threshold described above was not encountered in any of the forty-one (41) survey units addressed by Phase 3. Accordingly, the maximum ratios from LTP Chapter 5, Table 5-15 were used for all surrogate calculations During the FSS implementation, areas of interest were scanned with portable, hand-held radiation detection meters. Prior to scanning, background levels were determined, and investigation levels set in accordance with the Sample Plan. Areas were then scanned for elevated readings. When an elevated area was found, the area was marked, and a sample collected at that location for gamma spectroscopy analysis and further evaluation.

3.6 Radiological Release Criteria All FSS for the land area surveys submitted in this Phase 3 FSSR were conservatively designed to the OpDCGL for surface soils and all results were compared to this value.

However, since the release criteria were based on the BcDCGL (25 mrem/yr), surpassing the OpDCGL did not disqualify a survey unit from meeting the release criteria provided that the Elevated Measurement Comparison (EMC) was not surpassed as well. The EMC

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 40 was not used during the FSS of the survey units addressed by this report. Several discrete, elevated areas of contamination were identified in several of these survey units during FSS however all residual radioactivity greater than the OpDCGL concentrations were remediated prior to demonstrating compliance.

4 Final Status Survey Protocol 4.1 Data Quality Objectives The DQO process as outlined in Section 2 of this report was applied for each FSS Sample Plan and contained basic elements common to all FSS Sample Plans at ZSRP. An outline of those elements that are presented in the ZSRP FSS Sample Plans are as follows:

State the Problem The problem: To demonstrate that the level of residual radioactivity in a survey unit does not exceed the release criteria of 25 mrem/yr TEDE and that the potential dose from residual radioactivity is ALARA.

Stakeholders: The primary stakeholders interested in the answer to this problem are ZionSolutions LLC, Exelon, the Illinois Environmental Management Agency (IEMA) and the NRC.

The Planning Team: The planning team consisted of the assigned RE with input from other C/LT personnel as well as the Safety Department. The primary decision makers were the Technical Lead/RE with input from the C/LT Manager.

Schedule: The approximate time projected to mobilize, implement, and assess an FSS unit was approximately eight (8) days.

Resources: The following resources were necessary to implement an FSS Sample Plan:

  • RE to prepare the plan and evaluate data,
  • C/LT Field Supervisor to monitor and coordinate field activities,
  • Survey Mapping/computer aided design (CAD) Specialist to prepare survey maps, layout diagrams, composite view drawings, and other graphics as necessary to support design and reporting,
  • C/LT Technicians to perform survey activities, collect survey measurement data, and collect media samples,
  • Chemistry/Analysis laboratory Staff to analyze samples as necessary.

Identify the Decision Principal Study Question: Are the residual radionuclide concentrations found in the soil equal to or below site-specific DCGLs for surface soils?

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 41 Alternate Actions: Alternative actions included failure of the survey unit, remediation, reclassification, and resurvey.

The Decision: If the survey unit failed to demonstrate compliance with the release criteria, then the survey unit would not be suitable for unrestricted release. The DQA process was reviewed to identify the appropriate additional action or combination of actions.

Identify Inputs to the Decision Information Needed: The survey unit required evaluation of residual activity and its surface area. The characterization surveys and HSA were preliminary sources of information for FSS. New measurements of sample media were needed to determine the concentration and variability for those radionuclides potentially present at the site at the time of FSS.

Historical Information: The classification as originally identified in the HSA and the verification of that classification during characterization. A summary of site processes or incidents that occurred in the survey unit.

Radiological Survey Data: The current radiological survey data from the HSA and from characterization was used to develop a sample size for FSS.

Radionuclides of Concern: The ROC for the FSS of open land areas are presented in Section 2.2, Table 2-3, of this report.

Basis for the Action Level: The action level for the FSS of Class 1 open land areas was the OpDCGL, in accordance with Table 5-25 of the LTP.

During FSS, concentrations for HTD ROC, Ni-63 and Sr-90, were inferred using a surrogate approach. As presented in the LTP, Cs-137 is the principle surrogate radionuclide for Sr-90 and Co-60 is the principle surrogate radionuclide for Ni-63. The mean, maximum and 95% Upper Confidence Level (UCL) of the surrogate ratios for concrete core samples taken in the Auxiliary Building basement were calculated in ZionSolutions TSD-14-019, Radionuclides of Concern for Soil and Basement Fill Model Source Terms (Reference 25) and are presented in Table 4-1. The maximum ratios are used in the surrogate calculations during FSS unless area specific ratios are determined by continuing characterization.

Table 4-1, Surrogate Ratios Ratios Auxiliary Building Mean Max 95% UCL Ni-63/Co-60 44.143 180.450 154.632 Sr-90/Cs-137 0.001 0.002 0.002 For the FSS of the relevant survey units in this report, the surrogate OpDCGLs for Co-60 and Cs-137 were computed based on the maximum ratios from Table 4-1.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 42 The equation for calculating a surrogate DCGL is as follows:

Equation 1

=

1

1

+

2 2+

3 3+

Where:

DCGLSur

= Surrogate radionuclide DCGL DCGL2,3n = DCGL for radionuclides to be represented by the surrogate Rn

= Ratio of concentration (or nuclide mixture fraction) of radionuclide n to surrogate radionuclide Using the OpDCGLs presented in Table 2-1 and the maximum ratios from Table 4-1, the following surrogate calculations were performed:

Equation 2 (137) =

1

1 3.630(137)+

0.002 3.095(90)

= 3.622 /

The surrogate OpDCGL that was used for Cs-137 in the survey units for direct comparison of sample results to demonstrate compliance is 3.622 pCi/g.

Equation 3 (60) =

1

1 1.091(60)+

180.45 914.458(63)

= 0.898 /

The surrogate OpDCGL that was used for Co-60 in the survey units for direct comparison of sample results to demonstrate compliance is 0.898 pCi/g.

The action level for investigation in a Class 1 open land survey unit is the OpDCGL. The surrogate DCGL for Co-60 while inferring Ni-63 is 0.898 pCi/g, and the surrogate DCGL for Cs-137 while inferring Sr-90 is 3.622 pCi/g. Using the normalized mixture for gamma emitting ROC from Table 2-4, the surrogate adjusted gamma DCGL is then calculated as follows:

Equation 4

() =

1

0.012 0.898(60)+ 0.00001 1.733134+

0.988 3.622(137)

= 3.494 /

The surrogate adjusted gamma DCGL that was used in the survey units for direct comparison of sample results to demonstrate compliance was 3.494 pCi/g.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 43 Investigation Levels: The scan investigation level was based on the normalized surrogate adjusted DCGLs for gamma emitting ROC. Investigation levels for direct comparison of sample analysis results were in accordance with Table 5-25 of the LTP.

Sampling and Analysis Methods to Meet the Data Requirements: Surface soil samples were collected down to a depth of 0.15-meters (6-inches) and analyzed for gamma emitting radionuclides by the on-site gamma spectroscopy. The media consisted of soils and sand as required to complete the FSS. Subsurface soil sampling was collected using hand-auger or GeoProbe technology to a depth of 1-meter.

The target MDC for the analysis of sample media using laboratory instruments was 10% of the applicable OpDCGL. If necessary, measurement results with associated MDC that exceeded these values were accepted as valid data after evaluation by C/LT Supervision.

This situation was not encountered during the analysis of sample media from the FSS of survey units addressed by this Phase 3 FSSR.

In accordance with LTP Chapter 5, section 5.1, 10% of the volumetric samples acquired for FSS or, any sample with a SOF in excess of 0.1 when compared against the OpDCGL (OpSOF) were sent off-site for HTD ROC analysis. These analyses aimed to reaffirm that the radionuclide mix was not significantly different than that assumed in the LTP.

All activities were subject to the requirements of the QAPP for Characterization and FSS, which requires, among other things, the use of trained technicians, calibrated instruments, and procedures. In addition to these requirements, a minimum of 5% of the required number of samples were selected for Quality Control (QC) evaluation. At least one (1) duplicate soil sample was collected in each survey unit for QC evaluation.

Define the Boundaries of the Survey Boundaries of the Survey: The actual physical boundaries as stated for each survey unit.

Temporal Boundaries: The times and dates the survey was performed. Scanning and sampling in a survey unit was normally performed only during daylight and dry weather.

Constraints: The most common constraints were the weather, brush or undergrowth, and standing water in a survey unit.

Develop a Decision Rule Decision Rule: If any measurement data results exceeded the release criteria, the DQA process would be used to evaluate alternative actions.

Specify Tolerable Limits on Decision Errors The Null Hypothesis: Residual radioactivity in the survey unit exceeds the release criteria.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 44 Type I Error: This is also known as the error. This is the error associated with incorrectly concluding the null hypothesis has been rejected. In accordance with LTP section 5.6.4.1.1, the error was set at 0.05 (5%).

Type II Error: This is also known as the error. This is the error associated with incorrectly concluding the null hypothesis has been accepted. In accordance with LTP section 5.6.4.1.1, the error was set at 0.05 (5%).

The Lower Bound of the Gray Region (LBGR): The LBGR was set at 50% of the OpDCGL.

In using the unity rule, the OpDCGL becomes one (1) and the LBGR is set as 0.5.

Optimize Design Type of Statistical Test: The Sign Test was selected as the non-parametric statistical test for FSS. The Sign Test is conservative as it increases the probability of incorrectly accepting the null hypothesis (i.e., the conclusion will be that the survey unit does not meet the release criteria) and does not require the selection or use of a background reference area.

Number of Non-Parametric Samples: In the majority of the open land survey units addressed by this Phase 3 FSSR, 17 surface soil samples were required for the non-parametric statistical test (sample size N = 17). In four (4) of the forty-one (41) survey units (survey units 10220D, 10220E, 10220F and 10220G), fifteen (15) surface soil samples were required for the non-parametric statistical test (sample size N = 15) and in one of the forty-one (41) survey units (survey unit 10220B), fourteen (14) surface soil samples were required for the non-parametric statistical test (sample size N = 14). The locations of the samples were determined using software VSP.

Number of Judgmental Samples and Locations: The selection of judgmental samples was at the discretion of the C/LT Engineer. Locations chosen for sampling were usually areas of interest (small piles, trenches, etc.) and any areas of elevated radiation identified by scan.

Number of Scan Areas and Locations: LTP Chapter 5, section 5.6.4.4 and Table 5-24, for Class 1 open land survey units, the scan coverage requirement is that 100 percent of the accessible soil surface will be scanned. Walkover scans were conducted with a Ludlum Model 2350-1 instrument coupled to a Ludlum Model 44-10 Sodium Iodide (NaI) detector at a scanning speed of 0.25 m/sec. In some cases, scanning was prevented by physical obstacles such as standing water. In these cases, the inability to scan was addressed in the Release Record.

Number of Samples for Quality Control: The implementation of quality control measures as referenced by LTP Chapter 5, section 5.9 and the QAPP included the collection of a soil sample for split sample analysis on 5% of the soil samples taken in a survey unit with the locations selected at random.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 45 Power Curve: The Prospective Power Curve, developed using characterization data and MARSSIM 2000 software, showed adequate power for the survey design in each of the survey units.

4.2 Survey Unit Designation and Classification Procedure ZS-LT-300-001-002, Survey Unit Classification (Reference 26), defines the decision process for classifying an area in accordance with the LTP and MARSSIM.

During the FSS of areas submitted for the Phase 3 FSSR, no survey units were reclassified during the performance of FSS. All survey units addressed by this Phase 3 FSSR were classified as Class 1 at the time of FSS.

4.3 Background Determination During FSS area scanning, ambient backgrounds were determined. As a conservative measure, technicians established an Alarm Set Point (ASP) for the Ludlum Model 2350-1 instrument coupled to a Ludlum Model 44-10 NaI detector at the MDCR of the instrument plus the background for each scan area. At no time did the ASP exceed the scan investigation level based on the normalized surrogate adjusted DCGLs for gamma emitting ROC. The results of scans in each survey unit addressed by this Phase 3 FSSR is provided in the Release Records.

4.4 Final Status Survey Sample Plans The level of effort associated with planning a survey is based on the complexity of the survey and nature of the hazards. Guidance for preparing FSS plans is provided in procedure ZS-LT-300-001-001 Final Status Survey Package Development. The FSS plan uses an integrated sample design that combines scanning surveys and sampling.

4.5 Survey Design 4.5.1 Determination of Number of Data Points The number of soil samples for FSS was determined in accordance with procedure ZS-LT-300-001-001 Final Status Survey Package Development and MARSSIM. The relative shift (/) for the survey unit data set is defined as shift (), which is the Upper Boundary of the Gray Region (UBGR), or the OpDCGL (SOF of 1), minus the LBGR (SOF of 0.5),

divided by sigma (), which is the standard deviation of the data set used for survey design (characterization). If the calculated relative shift for a survey unit was greater than 3, then a value of 3 was used as the adjusted /.

A breakdown of the number of soil samples collected for the Phase 3 survey units is provided in Table 4-2 below.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 46 Table 4-2, Number of Surface Soil Samples for FSS Survey Unit Description Area Class

  1. of Samples Spacing (m2)

(initial/Final)

NP Judg Inv QC (m) 10201A NE Corner of Restricted Area - Lakeshore 1,554 3/1 17 0

0 1

10.3 10201B NE Corner of Restricted Area - Lakeshore 1,427 3/1 17 0

0 1

9.8 10201C NE Corner of Restricted Area - Lakeshore 1,379 3/1 17 0

0 1

9.7 10201D NE Corner of Restricted Area - Lakeshore 1,472 3/1 17 0

0 2

10.0 10202A IRSF/Fire Training Area 1,757 3/1 17 0

0 1

10.7 10202B IRSF/Fire Training Area 1,711 3/1 17 0

0 3

10.8 10202C IRSF/Fire Training Area 1,696 3/1 17 0

0 1

10.7 10202D IRSF/Fire Training Area 1,680 3/1 17 0

0 1

10.7 10203D East Training Area 1,993 3/1 17 1

0 2

11.6 10203E East Training Area 1,886 3/1 17 0

3 2

11.3 10209A Restricted Area South of Gate House 1,966 3/1 17 0

5 2

11.6 10209B Restricted Area South of Gate House 1,977 3/1 17 0

0 1

11.6 10209D Restricted Area South of Gate House 1,586 3/1 17 0

0 1

10.4 10209E Restricted Area South of Gate House 1,560 3/1 17 1

5 2

10.3 10210A Restricted Area South of Turbine Building 1,788 3/1 17 0

0 1

11.0 10210B Restricted Area South of Turbine Building 1,913 3/1 17 0

0 1

11.4 10210C Restricted Area South of Turbine Building 1,893 3/1 17 0

0 1

11.3 10211A SE Corner of Restricted Area (Lakeshore) 1,536 3/1 17 0

0 1

10.2 10211B SE Corner of Restricted Area (Lakeshore) 1,663 3/1 17 0

0 2

10.6 10220B SE Corner of Exclusion Area - Inland 1,696 3/1 14 1

0 1

11.8 10220D SE Corner of Exclusion Area - Inland 1,475 3/1 15 0

0 1

10.7 10220E SE Corner of Exclusion Area - Inland 1,976 3/1 15 0

0 1

12.3 10220F SE Corner of Exclusion Area - Inland 1,578 3/1 15 0

0 1

11.0 10220G SE Corner of Exclusion Area - Inland 1,674 3/1 15 0

0 2

11.4 10220J SE Corner of Exclusion Area - Inland 2,030 3/1 17 0

0 1

11.7 10221B South of Protected Area - Inland 1,855 3/1 17 9

10 3

11.3 10221E South of Protected Area - Lakeshore 1,975 3/1 17 0

0 1

11.6 10221F South of Protected Area - Lakeshore 1,968 3/1 17 0

0 1

11.6 10221G South of Protected Area - Lakeshore 1,956 3/1 17 0

0 1

11.5 10221H South of Protected Area - Lakeshore 1,994 3/1 17 0

0 1

11.6 12101 WWTF Sludge Drying Bed Area 2,036 1/1 17 0

0 1

11.8 12102 WWTF 2,024 1/1 17 0

0 1

11.7 12103 Unit 2 PWST/SST Area 2,034 1/1 17 0

0 1

11.8 12112 Unit 1 PWST/SST Area West 1,693 1/1 17 0

2 3

10.7 12113 Unit 1 PWST/SST Area West 1,658 1/1 17 0

0 1

10.6 12203B Under Service Building and Southeast Yard 1,989 2/1 17 0

0 1

11.6 12203C Under Service Building and Southeast Yard 1,955 2/1 17 0

0 1

11.5 12203D Under Service Building and Southeast Yard 1,635 2/1 17 0

0 1

10.5 12204A Crib House Area 1,943 2/1 17 0

0 1

11.5 12204B Crib House Area 1,971 2/1 17 0

0 1

11.6 12204C Crib House Area 1,994 2/1 17 0

0 3

11.6

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 47 4.5.2 Sample Locations Locations of the samples were determined using software VSP. VSP software imports a topographical map of the selected survey area and designates the sample locations with coordinates and bearings based on the Illinois State Plane System NAD 1983 East. Pacific Northwest National Laboratory (PNNL) created VSP for the United States Department of Energy. For those locations where access was impractical or unsafe, alternate random sample locations were generated and documented. Sample locations were identified using GPS coordinates and are consistent with the Illinois State Plane System. Once located, sample points were physically marked as required by ZS-LT-300-001-001 and graphically plotted using drafting software.

4.6 Instrumentation Radiation detection and measurement instrumentation for performing FSS was selected to provide both reliable operation and adequate sensitivity to detect the ROC identified at the site at levels sufficiently below the OpDCGL. Detector selection was based on detection sensitivity, operating characteristics and expected performance in the field.

The DQO process included the selection of instrumentation appropriate for the type of measurement to be performed (i.e., scan measurements and sample analysis) that were calibrated to respond to a radiation field under controlled circumstances; evaluated periodically for adequate performance to established quality standards; and sensitive enough to detect the ROC with a sufficient degree of confidence.

Electronic data logging was used to the extent practicable to automatically record measurements to minimize transcription errors.

Specific implementing procedures controlled the issuance, use, and calibration of instrumentation used for FSS. The specific DQOs for instruments were established early in the planning phase for FSS activities, implemented by standard operating procedures and executed in the FSS Sample Plan.

4.6.1 Detector Efficiencies The Ludlum Model 2350-1 Data Logger coupled with the Ludlum Model 44-10 2-inch x 2-inch NaI Gamma Scintillation detector was selected as the primary radiation detection instrumentation for performing scanning for open land survey units for FSS at ZNPS.

4.6.2 Detector Sensitivities The evaluation of open land areas required a detection methodology of sufficient sensitivity for the identification of small areas of potentially elevated activity. Scanning measurements were performed by passing a hand-held detector, primarily the Ludlum Model 44-10 NaI detector, in gross count rate mode across the land surface under

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 48 investigation. The centerline of the detector was maintained at the ground to detector distance detailed in the sample plan and moved from side to side in a 1-meter wide pattern at a rate of 0.25 m/sec. The audible and visuals signals were monitored for detectable increases in count rate. An observed count rate increase resulted in further investigation to verify findings and to define the level and extent of residual radioactivity.

An a priori determination of scanning sensitivity was performed to ensure that the measurement system (including the surveyor) was able to detect concentrations of radioactivity at levels below the regulatory release limit. The specified performance level and surveyor efficiency was expressed in terms of scan MDCR. This sensitivity is the lowest count rate that can be reliably detected at any given background by the measurement system. The specified MDCR correlates to the targeted MDC.

This approach represents the surface scanning process for land areas defined in NUREG-1507, Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions (Reference 27). The gamma scan MDCR is discussed in detail in ZionSolutions TSD-11-004, Ludlum Model 44-10 Detector Sensitivity (Reference 28) which examines the gamma sensitivity for a 2-inch x 2-inch NaI detector to several radionuclide mixtures of Co-60 and Cs-137 at various detector distances and scan speeds. TSD-11-004 provides MDCR values for the expected ZNPS soil mixture based on detector background condition, scan speed, soil depth (0.15-meters), soil density (1.6 g/cm3) and detector distance to the surface of interest.

4.6.3 Instrument Maintenance and Control Control and accountability of survey instruments were maintained to assure the quality and prevent the loss of data. All personnel operating radiological instruments, analysis equipment, measurement location equipment etc., were qualified to operate any assigned equipment and recognize off normal results and indications.

4.6.4 Instrument Calibration Instruments and detectors were calibrated for the radiation types and energies of interest or to a conservative energy source. Instrument calibrations were documented with calibration certificates and/or forms and maintained with the instrumentation and project records.

Calibration labels were also attached to all portable survey instruments. Prior to using any survey instrument, the current calibration was verified, and all operational checks were performed.

Instrumentation used for FSS was calibrated and maintained in accordance with approved ZionSolutions site calibration procedures. Radioactive sources used for calibration were traceable to the NIST and were obtained in standard geometries to match the type of samples being counted. When a characterized high-purity germanium (HPGe) detector was used, suitable NIST-traceable sources were used for calibration, and the software set up

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 49 appropriately for the desired geometry. If vendor services were used, these were obtained in accordance with purchasing requirements for quality related services, to ensure the same level of quality.

4.7 Survey Methodology 4.7.1 Scan Surveys The LTP specifies the minimum amount of scanning required for each class as summarized in Table 4-3. The total fraction of scanning coverage is determined during the DQO process with the amount, and location(s) based on the likelihood of finding elevated activity during FSS. As previously stated, all forty-one (41) open land survey units addressed by this Report were classified as Class 1 and required 100% areal scan coverage.

Table 4-3, Recommended Scan Coverage Area Classification Surface Scans Class 1 100%

Class 2 10% to 100%,

Systematic and Judgmental Class 3 Judgmental The survey unit was broken down into manageable scan grids. Each scan grid was located with GPS and marked. Each scan grid was completely scanned to the extent possible.

During the scanning, the technician recorded data and observations in a Field Log. This log documented field activities and other information pertaining to the survey. Where an area could not be scanned due to the presence of a physical obstruction or standing water, a notation was made in the Field Log and subsequently denoted in the Release Record.

Areas with elevated readings were marked and investigational samples were collected.

4.7.2 Soil Sampling In accordance with the FSS Sample Plan and applicable job aids, FSS technicians collected surface and subsurface soil samples at locations specified by the survey design. Each sample location was documented, along with soil conditions and observations, and a chain of custody was developed to maintain sample integrity.

4.8 Quality Control Surveys The method used for evaluating QC split samples collected in support of the FSS program is specified in the QAPP for Characterization and FSS. QC split data was assessed using criteria taken from the NRC Inspection Manual, Inspection Procedure 84750, NRC

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 50 Inspection Manual, Inspection Procedure 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring (Reference 29).

A minimum of 5% of the sample locations used in the FSS design were selected randomly using the Microsoft Excel RANDBETWEEN function and submitted as splits. Most splits taken for FSS were field replicates, that is, samples obtained from one location, homogenized, divided into separate containers, and treated as separate samples. These samples were then used to assess errors associated with sample heterogeneity, sample methodology, and analytical procedures. It was desirable that when analyzed, there is agreement between the splits resulting in data acceptance. If there was no agreement between the samples, the RE evaluated the magnitude and impact on survey design, the implementation and evaluation of results as well as the need to perform confirmatory sampling. If the RE had determined that the discrepancy affected quality or was detrimental to the implementation of FSS, then a Condition Report would have been issued.

To maintain the quality of the FSS, isolation and control measures were implemented prior to and during survey activities upon completion of FSS until there was no risk of recontamination or upon license termination. Following FSS, and until the area is released, a semi-annual surveillance will be performed on completed FSS survey units. This includes an inspection of area postings, inspection of the area for signs of dumping or disturbance and biased sampling. In the event that isolation and control measures were compromised, a follow-up survey may be performed after evaluation.

5 Survey Findings Procedure ZS-LT-300-001-004, Final Status Survey Data Assessment, provides guidance to C/LT personnel to interpret survey results using the DQA process during the assessment phase of FSS activities.

The DQA process is the primary evaluation tool to determine that data is of the right type, quality and quantity to support the objectives of the FSS Sample Plan. The five steps of the DQA process are:

1. Review the Sample Plan DQOs and the survey design,
2. Conduct a preliminary data assessment,
3. Select the statistical test,
4. Verify the assumptions of the statistical test,
5. Draw conclusions from the data.

Data validation descriptors described in MARSSIM Table 9.3 were used during the DQA process to verify and validate collected data as required by the QAPP for Characterization and FSS.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 51 5.1 Survey Data Conversion During the data conversion, the RE-evaluated raw data for problems or anomalies encountered during Sample Plan activities (sample collection and analysis, handling and control, etc.) including the following:

  • Recorded data,
  • Missing values,
  • Deviation from established procedure, and
  • Analysis flags.

Once resolved, initial data conversion, which is part of preliminary data assessment was performed and consisted of converting the data into units relative to the release criteria (e.g., pCi/g) and calculating basic statistical quantities (e.g., mean, median, standard deviation). Table 5-1 provides a summary of the basic statistical properties for the FSS of Phase 3 Open Land Survey Units.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 52 Table 5-1, Basic Statistical Properties for FSS of Phase 3 Open Land Survey Units Survey Unit Description Mean OpSOF Max OpSOF

  1. OpSOF

>1 Radionuclide Statistical Summary Co-60 Cs-137 Max Mean St. Dev.

Max Mean St. Dev.

(pCi/g)

(pCi/g)

(pCi/g)

(pCi/g)

(pCi/g)

(pCi/g) 10201A NE Corner of Restricted Area - Lakeshore 0.047 0.080 0

6.18E-02 2.39E-02 1.80E-02 7.81E-02 3.00E-02 2.30E-02 10201B NE Corner of Restricted Area - Lakeshore 0.047 0.097 0

7.11E-02 2.47E-02 2.00E-02 7.92E-02 3.32E-02 2.80E-02 10201C NE Corner of Restricted Area - Lakeshore 0.045 0.088 0

4.82E-02 2.31E-02 1.70E-02 1.20E-01 3.53E-02 2.90E-02 10201D NE Corner of Restricted Area - Lakeshore 0.060 0.144 0

9.58E-02 3.33E-02 2.60E-02 1.35E-01 4.12E-02 3.30E-02 10202A IRSF/Fire Training Area 0.055 0.100 0

6.99E-02 3.22E-02 1.70E-02 7.52E-02 4.12E-02 2.30E-02 10202B IRSF/Fire Training Area 0.046 0.085 0

6.65E-02 2.57E-02 1.80E-02 9.33E-02 4.38E-02 2.00E-02 10202C IRSF/Fire Training Area 0.050 0.091 0

5.78E-02 2.71E-02 2.00E-02 8.30E+00 4.17E-02 2.30E-02 10202D IRSF/Fire Training Area 0.054 0.138 0

9.30E-02 2.78E-02 2.50E-02 1.19E-01 5.73E-02 3.70E-02 10203D East Training Area 0.041 0.122 0

5.54E-02 2.33E-02 1.50E-02 1.24E-01 3.43E-02 2.80E-02 10203E East Training Area 0.050 0.106 0

6.66E-02 2.99E-02 2.30E-02 9.02E-02 3.90E-02 2.90E-02 10209A Restricted Area South of Gate House 0.041 0.077 0

4.52E-02 2.19E-02 1.50E-02 7.12E-02 2.87E-02 2.70E-02 10209B Restricted Area South of Gate House 0.047 0.090 0

6.78E-02 2.39E-02 2.00E-02 1.22E-01 3.78E-02 3.20E-02 10209D Restricted Area South of Gate House 0.085 0.458 0

1.21E-01 3.62E-02 3.40E-02 1.10E+00 1.26E-01 2.52E-01 10209E Restricted Area South of Gate House 0.050 0.109 0

9.11E-02 2.46E-02 2.30E-02 7.17E-02 4.49E-02 2.20E-02 10210A Restricted Area South of Turbine Building 0.056 0.243 0

2.07E-01 3.03E-02 4.80E-02 2.25E-01 5.03E-02 6.00E-02 10210B Restricted Area South of Turbine Building 0.057 0.141 0

7.99E-02 3.17E-02 2.10E-02 5.54E-02 2.90E-02 1.80E-02 10210C Restricted Area South of Turbine Building 0.045 0.090 0

4.94E-02 2.24E-02 2.00E-02 9.89E-02 3.21E-02 2.30E-02 10211A SE Corner of Restricted Area (Lakeshore) 0.029 0.056 0

4.00E-02 1.44E-02 1.40E-02 6.00E-02 2.61E-02 1.90E-02 10211B SE Corner of Restricted Area (Lakeshore) 0.050 0.125 0

9.13E-02 2.73E-02 2.40E-02 6.23E-02 3.17E-02 1.70E-02 10220B SE Corner of Exclusion Area - Inland 0.047 0.111 0

7.49E-02 2.43E-02 2.10E-02 7.63E-02 3.27E-02 2.40E-02 10220D SE Corner of Exclusion Area - Inland 0.027 0.061 0

2.77E-02 8.91E-03 9.00E-03 6.64E-02 2.58E-02 2.00E-02 10220E SE Corner of Exclusion Area - Inland 0.031 0.081 0

5.48E-02 1.48E-02 1.70E-02 7.05E-02 2.21E-02 2.40E-02 10220F SE Corner of Exclusion Area - Inland 0.037 0.084 0

4.12E-02 1.94E-02 1.50E-02 7.86E-02 3.06E-02 2.10E-02 10220G SE Corner of Exclusion Area - Inland 0.042 0.150 0

9.82E-02 2.35E-02 2.60E-02 6.09E-02 2.76E-02 2.00E-02 10220J SE Corner of Exclusion Area - Inland 0.045 0.082 0

4.51E-02 2.10E-02 1.30E-02 5.74E-02 3.05E-02 1.70E-02 10221B South of Protected Area - Inland 0.038 0.116 0

5.96E-02 1.99E-01 1.90E-02 2.15E-01 3.27E-02 5.10E-02 10221E South of Protected Area - Lakeshore 0.055 0.109 0

8.07E-02 2.90E-02 2.50E-02 1.83E-01 4.56E-02 4.10E-02

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 53 Table 5-1 (continued), Basic Statistical Properties for FSS of Phase 3 Open Land Survey Units Survey Unit Description Mean OpSOF Max OpSOF

  1. OpSOF

>1 Radionuclide Statistical Summary Co-60 Cs-137 Max Mean St. Dev.

Max Mean St. Dev.

(pCi/g)

(pCi/g)

(pCi/g)

(pCi/g)

(pCi/g)

(pCi/g) 10221F South of Protected Area - Lakeshore 0.052 0.114 0

6.63E-02 2.76E-02 2.10E-02 2.15E-01 6.25E-02 5.80E-02 10221G South of Protected Area - Lakeshore 0.036 0.065 0

4.39E-02 1.80E-02 1.50E-02 7.96E-02 3.52E-02 2.30E-02 10221H South of Protected Area - Lakeshore 0.025 0.096 0

4.56E-02 1.24E-02 1.40E-02 6.18E-02 1.95E-02 2.00E-02 12101 WWTF Sludge Drying Bed Area 0.055 0.200 0

1.07E-01 2.45E-02 2.60E-02 2.83E-01 7.57E-02 7.10E-02 12102 WWTF 0.052 0.110 0

5.51E-02 2.36E-02 1.90E-02 1.38E-01 3.24E-02 4.00E-02 12103 Unit 2 PWST/SST Area 0.042 0.089 0

6.01E-02 2.17E-02 1.70E-02 1.07E-01 3.58E-02 2.20E-02 12112 Unit 1 PWST/SST Area West 0.046 0.093 0

6.32E-02 3.07E-02 1.80E-02 1.43E-01 7.50E-02 3.30E-02 12113 Unit 1 PWST/SST Area West 0.046 0.093 0

7.06E-02 2.65E-02 2.10E-02 1.06E-01 4.52E-02 3.00E-02 12203B Under Service Building and Southeast Yard 0.055 0.159 0

7.84E-02 2.95E-02 2.20E-02 2.40E-01 3.97E-02 5.90E-02 12203C Under Service Building and Southeast Yard 0.042 0.074 0

5.73E-02 1.99E-02 1.70E-02 1.03E-01 3.89E-02 3.00E-02 12203D Under Service Building and Southeast Yard 0.055 0.101 0

6.93E-02 2.84E-02 2.00E-02 1.22E-01 4.68E-02 3.00E-02 12204A Crib House Area 0.036 0.070 0

4.45E-02 1.60E-02 1.30E-02 4.84E-02 2.41E-02 1.40E-02 12204B Crib House Area 0.052 0.118 0

9.18E-02 2.66E-02 2.00E-02 1.04E-01 4.21E-02 2.70E-02 12204C Crib House Area 0.060 0.174 0

5.77E-02 2.55E-02 1.90E-02 4.58E-01 6.33E-02 1.06E-01

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 54 5.2 Survey Data Verification and Validation Items supporting DQO sample design and data were reviewed for completeness and consistency. These included:

  • Classification history and related documents,
  • Site description,
  • Survey design and measurement locations,
  • Analytic method and detection limits and that the required analytical method(s) were adequate for the radionuclides of concern,
  • Sampling variability provided for the radionuclides of interest,
  • QC measurements have been specified,
  • Survey and sampling result accuracy have been specified,
  • Field conditions for media and environment, and
  • Field records.

Documentation, as listed, was reviewed to verify completeness and that it was legible:

  • Field and analytical results,
  • Chain-of-custody,
  • Field Logs,
  • Instrument issue, return and source check records,
  • Instrument downloads, and
  • Measurement results relative to measurement location.

After completion of these previously mentioned tasks, a Preliminary Data Assessment record was initiated. This record served to verify that all data was reported in standard units in relation to the DCGLs and that the calculation of the statistical parameters needed to complete data evaluation were completed which, at a minimum, included the following:

  • The number of observations (i.e. samples or measurements),
  • The range of observations (i.e. minimum and maximum values),
  • Mean,
  • Median, and
  • Standard deviation.

In order to adequately evaluate the data set, consideration as additional options included the coefficient of variation, measurements of relative standing (such as percentile), and other statistical applications as necessary (frequency distribution, histograms, skew, etc.).

Finalization of the data review consisted of graphically displaying the data in distributions and percentiles plots.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 55 5.3 Anomalous Data/Elevated Scan Results and Investigation Survey Unit 10202B During the FSS of Class 1 open land survey unit 10202B, an investigation was performed following scan alarms in two (2) scan rows. Scan readings of 99,137 cpm and 9,573 cpm were recorded. Two initial investigation samples were acquired at the locations of the elevated scans. The analysis of the initial investigation samples showed 3.39E+02 pCi/g of Co-60 activity. Subsequently, a small radioactive particle was identified in the soil matrix of the sample and captured. A recount of the same sample following the removal of the particle showed no activity above MDC for the ROC. Remediation was performed at each of the elevated scan locations. Post-remediation surface and subsurface soil samples were acquired, and scans were performed which showed that the activity was removed from the survey unit.

Survey Unit 10202D During the FSS of Class 1 open land survey unit 10202D, an investigation was performed following a scan alarm. A scan measurement of 19,891 cpm was recorded. The activity was found to be a small radioactive particle, which was captured and placed in a separate container. The reading on the plastic bag was 127,818 cpm. Three (3) soil samples were taken following the removal of the particle along with a subsurface sample taken to a depth of 1-meter. Gamma spectroscopy results revealed that activity level for the ROC was less than MDC in all the samples. No other remediation was performed in this survey unit.

Survey Unit 10203D During the FSS of Class 1 open land survey unit 10203D, a judgmental surface soil sample was taken in an area of higher background readings. This sample was taken to verify that the higher background readings was due to clay in the soil. The gamma spectroscopy results revealed higher readings for the NORM nuclides, and activity level for the ROC less than MDC for Cs-134 and Co-60 and 7.46E-02 pCi/g for Cs-137.

Survey Unit 10203E During the FSS of Class 1 open land survey unit 10203E, an investigation was performed following a scan alarm. An area measuring approximately 2 meters x 2 meters in size was identified as elevated by scan. Two (2) surface soil samples were taken at the location of the elevated scan as well as an additional split QC sample and a subsurface sample to a depth of 1-meter. Gamma spectroscopy results revealed that positive Cs-137 activity was identified in two (2) of the samples at low levels. All other activity for the ROC was less than MDC in the samples.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 56 Survey Unit 10209A During the FSS of Class 1 open land survey unit 10209A, an investigation was performed following a scan alarm. A reading of 57,920 cpm was recorded. The activity was found to be a small radioactive particle, which was subsequently captured and removed. Five (5) investigation soil samples were taken following the removal of the particle. Gamma spectroscopy results revealed one (1) sample with an activity level above MDC for Cs-137, one (1) sample with an activity level above MDC for Co-60 and no samples with activity levels above MDC for Cs-134.

Survey Unit 10209E During the FSS of Class 1 open land survey unit 10209E, an investigation was performed following a scan alarm. An initial reading of 9,281 cpm was recorded. The activity was found to be a small radioactive particle located ~4-inches below the surface. When the particle was uncovered, a second reading of 35,412 cpm was recorded and the particle was captured. Five (5) investigation surface soil samples were taken following the removal of the particle. Gamma spectroscopy results revealed five (5) samples with activity levels above MDC for Cs-137, one (1) sample with an activity level above MDC for Co-60 and no samples with activity levels above MDC for Cs-134.

Survey Unit 10220B During the identification and marking of the non-parametric sample locations in Class 1 open land survey unit 10220B, several inches of water was present at one of the designated locations. As the actual location was deemed obstructed, the sample location was relocated to the closest suitable location for the acquisition of a surface soil sample. During the performance of the survey, the original sample location became unobstructed (water had receded). Consequently, an additional judgmental sample was acquired at the original location. No ROC concentration exceeded the OpDCGL in any compliance soil sample.

Survey Unit 10221B During the FSS of Class 1 open land survey unit 10221B, an investigation was performed based on the results of gamma scans performed under an RA on the railroad ballast located in survey unit 10221B and the soil areas 1-meter beyond the ballast gravel. The RA identified two (2) small areas of elevated activity, both less than 100 cm2, reading 3,200 cpm and 4,700 cpm. One (1) surface soil sample was taken at each location. Four (4) additional samples were taken in the immediate vicinity (within 0.5 meters) of each location. Gamma spectroscopy results revealed five (5) samples with activity levels above MDC for Cs-137, two (2) samples with activity levels above MDC for Co-60 and no samples with activity levels above MDC for Cs-134. Since the OpSOF for the investigation samples were all less than 1.0, with a maximum OpSOF of 0.529, no further action was deemed necessary.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 57 Survey Unit 10221H During the FSS of Class 1 open land survey unit 10221H, five (5) systematic samples were relocated to the closest adjacent suitable location due to the original locations falling on the railroad ballast which is made up of rock and not soil. No ROC concentration exceeded the OpDCGL in any compliance soil sample.

Survey Unit 12112 During the FSS of Class 1 open land survey unit 12112, an investigation was performed at the locations of two scan alarms. Two (2) surface soil samples and two (2) subsurface soil samples to a depth of 1-meter were taken at the location of the elevated scan as well as an additional QC split sample. The results of these samples showed a maximum OpSOF of 0.051. No further action was deemed necessary.

5.4 Evaluation of Number of Sample/Measurement Locations in Survey Units An effective tool utilized to evaluate the number of samples collected in the sampling design is the Retrospective Power Curve generated by MARSSIM 2000 or COMPASS.

The Retrospective Power Curve shows how well the survey design achieved the DQOs.

For reporting purposes, all Release Records include a Retrospective Power Curve analysis indicating that the sampling design had adequate power to pass the FSS release criteria (i.e.

adequate number of samples was collected).

The Sign Test was selected as the statistical test for all Release Records submitted in this report. This test, performed in accordance with ZS-LT-300-001-004, along with the Retrospective Power Curve demonstrates survey design adequacy. If the data passed the Sign Test and Retrospective Power Curve, the null hypothesis was rejected, and the survey unit was be released with no further actions required. For reporting purposes, all survey unit Release Records passed the Sign Test, indicating that the survey design was adequate (i.e. adequate number of samples was collected).

The EMC was not used during the FSS of the survey units addressed by this report.

Several discrete, elevated areas of contamination were identified in several of these survey units during FSS. However, all residual radioactivity greater than the OpDCGL concentrations were remediated prior to demonstrating compliance.

5.5 Comparison of Findings with Derived Concentration Guideline Levels The SOF or unity rule was applied to FSS data in accordance with the guidance provided in Section 2.7 of NUREG-1757, Vol. 2, and the LTP. This was accomplished by calculating a fraction of the OpDCGL for each sample or measurement by dividing the reported concentration by the OpDCGL. If a sample had multiple ROC, then the fraction of the OpDCGL for each ROC was summed to provide an OpSOF for the sample.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 58 Unity rule equivalents were calculated for each measurement result using the inferred concentration for the HTD ROC calculated using the maximum ratios from LTP Chapter 5, Table 5-15. The inferred concentrations were then compared against the applicable OpDCGL to derive a OpSOF for each ROC. The individual OpSOF for each ROC were then summed to derive an OpSOF for the sample. This was the value used to perform the Sign Test. The mean and maximum OpSOF for each open land survey unit addressed in this Phase 3 FSSR is presented in Table 5-1 of this report.

A Base Case SOF (BcSOF) was calculated for each ROC by dividing the reported concentration by the BcDCGL. A BcSOF of one is equivalent to the decision rule, meaning any measurement with a BcSOF of one or greater, would not meet the 25 mrem/yr release criteria. The mean BcSOF was multiplied by 25 to establish the dose attributed to soil in a survey unit. A summary of the mean BcSOF and dose contribution for each Phase 3 survey unit is provided in Table 5-2 below.

Table 5-2, Mean Base Case SOF and Dose Contribution from Soil Survey Unit Description Mean BcSOF Dose Survey Unit Description Mean BcSOF Dose (mrem/yr)

(mrem/yr) 10201A NE Corner of Restricted Area - Lakeshore 0.012 0.299 10220E SE Corner of Exclusion Area - Inland 0.008 0.196 10201B NE Corner of Restricted Area - Lakeshore 0.012 0.303 10220F SE Corner of Exclusion Area - Inland 0.009 0.233 10201C NE Corner of Restricted Area - Lakeshore 0.012 0.288 10220G SE Corner of Exclusion Area - Inland 0.011 0.270 10201D NE Corner of Restricted Area - Lakeshore 0.015 0.385 10220J SE Corner of Exclusion Area - Inland 0.012 0.289 10202A IRSF/Fire Training Area 0.014 0.354 10221B South of Protected Area

- Inland 0.010 0.245 10202B IRSF/Fire Training Area 0.012 0.292 10221E South of Protected Area

- Lakeshore 0.014 0.353 10202C IRSF/Fire Training Area 0.013 0.319 10221F South of Protected Area

- Lakeshore 0.013 0.331 10202D IRSF/Fire Training Area 0.014 0.348 10221G South of Protected Area

- Lakeshore 0.009 0.233 10203D East Training Area 0.011 0.263 10221H South of Protected Area

- Lakeshore 0.007 0.163 10203E East Training Area 0.013 0.323 12101 WWTF Sludge Drying Bed Area 0.014 0.355 10209A Restricted Area South of Gate House 0.011 0.264 12102 WWTF 0.013 0.330 10209B Restricted Area South of Gate House 0.012 0.304 12103 Unit 2 PWST/SST Area 0.011 0.271 10209D Restricted Area South of Gate House 0.022 0.544 12112 Unit 1 PWST/SST Area West 0.018 0.449 10209E Restricted Area South of Gate House 0.013 0.318 12113 Unit 1 PWST/SST Area West 0.012 0.297 10210A Restricted Area South of Turbine Building 0.014 0.361 12203B Under Service Building and Southeast Yard 0.014 0.352

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 59 Table 5-2 (continued), Mean Base Case SOF and Dose Contribution from Soil Survey Unit Description Mean BcSOF Dose Survey Unit Description Mean BcSOF Dose (mrem/yr)

(mrem/yr) 10210B Restricted Area South of Turbine Building 0.015 0.365 12203C Under Service Building and Southeast Yard 0.012 0.268 10210C Restricted Area South of Turbine Building 0.012 0.287 12203D Under Service Building and Southeast Yard 0.014 0.354 10211A SE Corner of Restricted Area (Lakeshore) 0.008 0.189 12204A Crib House Area 0.009 0.229 10211B SE Corner of Restricted Area (Lakeshore) 0.013 0.321 12204B Crib House Area 0.013 0.335 10220B SE Corner of Exclusion Area - Inland 0.012 0.302 12204C Crib House Area 0.015 0.383 10220D SE Corner of Exclusion Area - Inland 0.007 0.173 5.6 Description of ALARA to Achieve Final Activity Levels Section N.1.5 of NUREG-1757, Vol. 2, states that For residual radioactivity in soil at sites that may have unrestricted release, generic analyses show that shipping soil to a low-level waste disposal facility is unlikely to be cost effective for unrestricted release, largely because of the high costs of waste disposal. Therefore, shipping soil to a low-level waste disposal facility generally does not have to be evaluated for unrestricted release. Section 4.4.1 of LTP Chapter 4 presents a simple ALARA analysis for the excavation and disposal of soils as low-level radioactive waste that confirms the statement in section N.1.5 of NUREG-1757, Vol. 2 that the cost of disposing excavated soil as low-level radioactive waste is clearly greater than the benefit of removing and disposing of soil with residual radioactivity concentrations less than the dose criterion. Since the cost is greater than the benefit, it is not ALARA to excavate and dispose of soils with residual radioactivity concentrations below the DCGL.

5.7 NRC/Independent Verification Team Findings As of the date of this report, the Oak Ridge Institute for Science and Education (ORISE) has performed confirmatory surveys in several of the forty-one (41) survey units addressed by this Phase 3 FSSR. While no official report detailing the findings of the confirmatory surveys has yet been issued, no indications have been received that any conclusion of the survey would question the adequacy of the FSS performed in the Phase 3 open land survey units.

6 Summary Final Status Survey (FSS) is the process used to demonstrate that the ZNPS structures and soils comply with the radiological criteria for unrestricted use specified in 10 CFR 20.1402.

The purpose of FSS Sample Plan is to describe the methods to be used in planning, designing, conducting, and evaluating the FSS.

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 60 The two radiological criteria for unrestricted use specified in 10CFR20.1402 are: 1) the residual radioactivity that is distinguishable from background radiation results in a TEDE to an AMCG that does not exceed 25 mrem/yr, including that from groundwater sources of drinking water, and 2) the residual radioactivity has been reduced to levels that are ALARA.

The forty-one (41) Class 1 open land survey units addressed in this Final Report have met the DQOs of the FSS Sample Plans developed and implemented for each. In each survey unit, all identified ROC were used for statistical testing to determine the adequacy of the survey unit for FSS, the sample data passed the Sign Test, the null hypothesis was rejected, and a Retrospective Power Curve showed that adequate power was achieved. Each of the forty-one (41) survey units were properly classified as Class 1. Evaluation of the data for each survey unit shows that none of the ROC concentration values exceeded the OpDCGL or any investigational levels and therefore, in accordance with the LTP Section 5.10, each of the survey units addressed in this Phase 3 FSSR meets the release criterion.

7 References

1. Zion Station Restoration Project License Termination Plan
2. NUREG-1575, Multi-Agency Radiation Survey and Site Investigation Manual
3. ZS-LT-01, Quality Assurance Project Plan (for Characterization and FSS)
4. ZS-LT-300-001-001, Final Status Survey Package Development
5. ZS-LT-300-001-003, Isolation and Control for Final Status Survey
6. ZS-LT-300-001-004, Final Status Survey Data Assessment
7. NUREG-1757, Vol. 2, Consolidated Decommissioning Guidance Characterization, Survey, and Determination of Radiological Criteria
8. ZS-LT-300-001-005, Final Status Survey Data Reporting
9. Zion Station Historical Site Assessment
10. TSD-14-011, Soil Area Factors
11. TSD-17-004, Operational Derived Concentration Guideline Levels for Final Status Survey
12. TSD-14-028, Radiological Characterization Report
13. ZS-RP-108-000-000, Radiological Instrumentation Program
14. ZS-RP-108-004-012, Calibration and Initial Set-Up of the 2350-1
15. LT-JA-004, FSS Sample Collection
16. ZS-LT-100-001-004, Sample Media Preparation

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 61

17. ZS-WM-131, Chain of Custody Protocol
18. ZS-QA-10, Quality Assurance Project Plan
19. [Amended] Post-Shutdown Decommissioning Activities Report
20. Defueled Safety Analysis Report
21. Offsite Dose Calculation Manual
22. ZS-LT-02, Characterization Survey Plan
23. TSD-11-001, Technical Support Document for Potential Radionuclides of Concern During the Decommissioning of the Zion Station
24. TSD-13-004, Examination of Cs-137 Global Fallout In Soils At Zion Station
25. TSD-14-019, Radionuclides of Concern for Soil and Basement Fill Model Source Terms
26. ZS-LT-300-001-002, Survey Unit Classification
27. NUREG-1507, Minimum Detectable Concentrations with Typical Radiation Survey Instruments for Various Contaminants and Field Conditions
28. TSD-11-004, Ludlum Model 44-10 Detector Sensitivity
29. NRC Inspection Manual, Inspection Procedure 84750, Radioactive Waste Treatment, and Effluent and Environmental Monitoring 8

Appendices A1 FSS Release Record, Survey Unit 10201A A2 FSS Release Record, Survey Unit 10201B A3 FSS Release Record, Survey Unit 10201C A4 FSS Release Record, Survey Unit 10201D A5 FSS Release Record, Survey Unit 10202A A6 FSS Release Record, Survey Unit 10202B A7 FSS Release Record, Survey Unit 10202C A8 FSS Release Record, Survey Unit 10202D A9 FSS Release Record, Survey Unit 10203D A10 FSS Release Record, Survey Unit 10203E A11 FSS Release Record, Survey Unit 10209A A12 FSS Release Record, Survey Unit 10209B A13 FSS Release Record, Survey Unit 10209D A14 FSS Release Record, Survey Unit 10209E A15 FSS Release Record, Survey Unit 10210A A16 FSS Release Record, Survey Unit 10210B A17 FSS Release Record, Survey Unit 10210C

FINAL STATUS SURVEY FINAL REPORT - PHASE 3 Revision 0 62 A18 FSS Release Record, Survey Unit 10211A A19 FSS Release Record, Survey Unit 10211B A20 FSS Release Record, Survey Unit 10220B A21 FSS Release Record, Survey Unit 10220D A22 FSS Release Record, Survey Unit 10220E A23 FSS Release Record, Survey Unit 10220F A24 FSS Release Record, Survey Unit 10220G A25 FSS Release Record, Survey Unit 10220J A26 FSS Release Record, Survey Unit 10221B A27 FSS Release Record, Survey Unit 10221E A28 FSS Release Record, Survey Unit 10221F A29 FSS Release Record, Survey Unit 10221G A30 FSS Release Record, Survey Unit 10221H A31 FSS Release Record, Survey Unit 12101 A32 FSS Release Record, Survey Unit 12102 A33 FSS Release Record, Survey Unit 12103 A34 FSS Release Record, Survey Unit 12112 A35 FSS Release Record, Survey Unit 12113 A36 FSS Release Record, Survey Unit 12203B A37 FSS Release Record, Survey Unit 12203C A38 FSS Release Record, Survey Unit 12203D A39 FSS Release Record, Survey Unit 12204A A40 FSS Release Record, Survey Unit 12204B A41 FSS Release Record, Survey Unit 12204C

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