Text

Restoration Project: License Termination Plan, Chapter 6, Revision 2, Compliance with the Radiological Criteria for License Termination
	ML18052A958
Person / Time
Site:	Zion File:ZionSolutions icon.png
Issue date:	02/21/2018
From:	; ZionSolutions
To:	; Office of Nuclear Material Safety and Safeguards
References
	ZS-2018-0007
	Download: ML18052A958 (141)
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ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN CHAPTER 6, REVISION 2 COMPLIANCE WITH THE RADIOLOGICAL CRITERIA FOR LICENSE TERMINATION

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-i TABLE OF CONTENTS

6.

COMPLIANCE WITH THE RADIOLOGICAL CRITERIA FOR LICENSE TERMINATION 6-1 6.1.

Site Release Criteria...................................................................................................... 6-1 6.2.

General Site Description............................................................................................... 6-1 6.2.1.

Site Geology........................................................................................................... 6-1 6.2.2.

Site Hydrogeology................................................................................................. 6-2 6.2.3.

Area Land Use....................................................................................................... 6-2 6.2.4.

Area Groundwater Use.......................................................................................... 6-2 6.3.

Basements and Structures to Remain after License Termination (End State).............. 6-3 6.4.

Dose Modeling Overview............................................................................................. 6-4 6.4.1.

Backfilled Basement Structure Surfaces................................................................ 6-5 6.4.2.

Soil......................................................................................................................... 6-6 6.4.3.

Buried Piping......................................................................................................... 6-7 6.4.4.

Embedded Piping................................................................................................... 6-7 6.4.5.

Penetrations............................................................................................................ 6-7 6.4.6.

Alternate Scenarios................................................................................................ 6-8 6.5.

Basement Fill Conceptual Model.................................................................................. 6-9 6.5.1.

Source Term........................................................................................................... 6-9 6.5.2.

Radionuclides of Concern.................................................................................... 6-12 6.5.3.

Critical Group and Exposure Scenario................................................................ 6-20 6.5.4.

Exposure Pathways.............................................................................................. 6-21 6.6.

Basement Fill Computation Model............................................................................. 6-22 6.6.1.

DUST-MS Model................................................................................................. 6-22 6.6.2.

Sensitivity Analysis............................................................................................. 6-28 6.6.3.

RESRAD Model.................................................................................................. 6-30 6.6.4.

Uncertainty Analysis............................................................................................ 6-32 6.6.5.

BFM RESRAD Parameter Set and Groundwater Exposure Factor Calculation. 6-36 6.6.6.

BFM Groundwater Dose Factors......................................................................... 6-37 6.6.7.

BFM Drilling Spoils Dose Factors...................................................................... 6-38 6.6.8.

Basement Surface DCGLs................................................................................... 6-40 6.6.9.

Basement Surface Elevated Areas....................................................................... 6-45 6.7.

Alternate Exposure Scenarios for Backfilled Basements........................................... 6-46 6.8.

Soil Dose Assessment and DCGL.............................................................................. 6-48 6.8.1.

Soil Source Term................................................................................................. 6-49 6.8.2.

Soil Radionuclides of Concern, Insignificant Contributor Dose and Surrogate Ratio.................................................................................................... 6-49 6.8.3.

Soil Exposure Scenario and Critical Group......................................................... 6-51 6.9.

Soil Computation Model - RESRAD v7.0................................................................. 6-51 6.9.1.

Parameter Selection............................................................................................. 6-51 6.9.2.

Uncertainty Analysis............................................................................................ 6-52 6.10.

RESRAD Results and Soil DCGLs......................................................................... 6-54 6.11.

Soil Area Factors..................................................................................................... 6-55 6.12.

Buried Piping Dose Assessment and DCGL........................................................... 6-55 6.12.1.

Buried Pipe Source Term and Radionuclides of Concern............................. 6-56

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-ii 6.12.2.

Buried Pipe Exposure Scenario and Critical Group...................................... 6-57 6.12.3.

Buried Pipe RESRAD Model for Excavation Scenario................................. 6-57 6.12.4.

Buried Pipe RESRAD Model for Insitu Scenarios........................................ 6-58 6.12.5.

Buried Pipe Uncertainty Analysis.................................................................. 6-58 6.12.6.

Buried Pipe RESRAD Results....................................................................... 6-60 6.12.7.

Buried Piping DCGL..................................................................................... 6-60 6.12.8.

Adjustment for Dose from Insignificant Contributors................................... 6-61 6.13.

Embedded Piping DCGL......................................................................................... 6-62 6.13.1.

Dose Calculation for Grouted Auxiliary Basement Floor Drains.................. 6-64 6.14.

Penetration DCGL................................................................................................... 6-66 6.15.

Existing Groundwater Dose..................................................................................... 6-68 6.16.

Clean Concrete Fill.................................................................................................. 6-68 6.17.

Demonstrating Compliance with Dose Criterion.................................................... 6-69 6.18.

References............................................................................................................... 6-71 LIST OF TABLES Table 6-1 Basements and Below Ground Structures included in the ZNPS End State.......... 6-4 Table 6-2 Initial Suite of Potential Radionuclides for ZNPS and Radionuclide Mixture Based on Auxiliary and Containment Concrete.................................................. 6-15 Table 6-3 IC Dose from Mixtures........................................................................................ 6-17 Table 6-4 IC Dose from Individual Cores (Normalized)..................................................... 6-17 Table 6-5 Zion Radionuclides of Concern for Containment and Auxiliary Basements..... 6-19 Table 6-6 Radionuclide Ratios from Concrete Cores.......................................................... 6-20 Table 6-7 General Parameters for DUST-MS Modeling..................................................... 6-24 Table 6-8 Distribution Coefficients for DUST-MS Modeling............................................. 6-24 Table 6-9 Basement Mixing Volumes for DUST-MS Modeling......................................... 6-26 Table 6-10 Summary of DUST-MS Source Term Release Rate Assumptions for the Zion Basements........................................................................................ 6-27 Table 6-11 Range of Diffusion Coefficients for Cement and Selected Values for Radionuclides of Concern (Reference 6-21)....................................................... 6-28 Table 6-12 Range of DUST-MS Parameters Varied in Sensitivity Analysis......................... 6-28 Table 6-13 Peak Groundwater Concentration Factors (pCi/L per mCi Total Inventory)...... 6-30 Table 6-14 Peak Fill Material Concentration Factors (pCi/g per mCi Total Inventory)........ 6-30 Table 6-15 BFM Uncertainty Analysis Results for Parameters with lPRCCl > 0.25............. 6-34 Table 6-16 BFM Deterministic Values for Sensitive Parameters from Table 6-12 that are Radionuclide Independent...................................................................... 6-35 Table 6-17 BFM Deterministic Values for Sensitive Parameters from Table 6-12 that are Radionuclide Dependent........................................................................ 6-35 Table 6-18 RESRAD Results and GW Exposure Factors for BFM model............................ 6-36 Table 6-19 BFM GW Dose Factors (mrem/yr per mCi Total Inventory).............................. 6-37 Table 6-20 BFM Drilling Spoils Dose Factors (mrem/yr per mCi Total Inventory)............. 6-39 Table 6-21 Basement Surface Areas (Walls and Floors)....................................................... 6-42

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-iii Table 6-22 Surface Areas for Circulating Water Intake Pipe, Circulating Water Discharge Tunnel, Circulating Water Discharge Pipes and Buttress Pits/Tendon Tunnels.............................................................................. 6-43 Table 6-23 Adjusted Basement Surface Areas for DCGL Calculation.................................. 6-43 Table 6-24 Adjusted BFM Groundwater Scenario DCGLBS (Adjusted for IC Dose)........... 6-44 Table 6-25 Adjusted BFM Drilling Spoils Scenario DCGLBS (Adjusted for IC Dose)......... 6-44 Table 6-26 Adjusted Basement DCGLB (Adjusted for IC Dose)........................................... 6-45 Table 6-27 Large Scale Industrial Excavation Alternate Scenario Dose............................... 6-47 Table 6-28 The maximum hypothetical resident farmer doses from penetrations for the Alternate Drilling Spoils Scenario (assuming well drilled 30 years after license termination)...................................................................... 6-48 Table 6-29 The maximum hypothetical resident farmer doses from embedded pipe for the Alternate Drilling Spoils Scenario (assuming well drilled 30 years after license termination)..................................................................................... 6-48 Table 6-30 The maximum hypothetical resident farmer dose from basement surfaces for the Alternate Drilling Spoils Scenario (assuming well drilled 30 years after license termination)..................................................................................... 6-48 Table 6-31 Soil ROC Mixture and IC Dose Percentage Using the Table 6-2 Best Estimate Mixture............................................................... 6-50 Table 6-32 Soil IC Dose and Dose Percentage using Soil Sample Results........................... 6-50 Table 6-33 Distribution Coefficients for Surface and Subsurface Soil RESRAD Analysis.. 6-52 Table 6-34 Surface Soil DCGL Uncertainty Analysis Results for Parameters with lPRCCl >0.25............................................................................................... 6-53 Table 6-35 Selected Deterministic Values for Surface Soil DCGL Sensitive Parameters from Table 6-21 That Are Radionuclide Independent...................... 6-53 Table 6-36 Deterministic Values for Surface Soil DCGL Sensitive Parameters from Table 6-21 that are Radionuclide Dependent............................................. 6-53 Table 6-37 Subsurface Soil DCGL Uncertainty Analysis Results for Parameters with lPRCCl > 0.25........................................................................... 6-54 Table 6-38 Selected Deterministic Values for Subsurface Soil DCGL Sensitive Parameters from Table 6-28 that are Radionuclide Independent........................ 6-54 Table 6-39 Deterministic Values for Subsurface Soil DCGL Sensitive Parameters from Table 6-28 that are Radionuclide Dependent...................................................... 6-54 Table 6-40 Adjusted Surface Soil and Subsurface Soil DCGLs (Adjusted for IC Dose)..... 6-55 Table 6-41 Surface Soil Area Factors.................................................................................... 6-56 Table 6-42 Subsurface Soil Area Factors............................................................................... 6-56 Table 6-43 RESRAD DSR Results for Buried Pipe Dose Assessment to Support DCGL Development....................................................................................................... 6-60 Table 6-44 Maximum Summed RESRAD DSRs from Excavation and Insitu Scenarios.... 6-61 Table 6-45 Buried Piping DCGLs (Not Adjusted for IC Dose)............................................. 6-61 Table 6-46 Adjusted Buried Pipe DCGLs (Adjusted for IC Dose)........................................ 6-62 Table 6-47 Embedded Pipe Survey Unit Surface Areas........................................................ 6-63 Table 6-48 Embedded Pipe DCGLEP (Adjusted for Insignificant Contributor Dose)........... 6-64 Table 6-49 Fractional Release of Residual Radioactivity from Auxiliary Floor Drains Due to presence of 1 Foot of Grout................................................ 6-65

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-iv Table 6-50 Penetration Survey Unit Surface Areas............................................................... 6-66 Table 6-51 Ratio of Instant Release Maximum to Diffusion Release Maximum for Auxiliary Basement........................................................ 6-67 Table 6-52 Adjusted Penetration DCGLPN (adjusted for insignificant contributor dose)...... 6-68 Table 6-53 Dose Assigned to Clean Concrete Fill................................................................. 6-69 LIST OF FIGURES Figure 6-1 Zion Nuclear Power Station Geographical Location........................................... 6-73 Figure 6-2 Zion Nuclear Power Station Owner Controlled Area.......................................... 6-74 Figure 6-3 Zion Nuclear Power Station Security Restricted Area........................................ 6-75 Figure 6-4 Backfilled Basement and Structures to Remain Below 588 Elevation.............. 6-76 Figure 6-5 Cross Section A-A of Basements/Structures Below............................................ 6-77 Figure 6-6 Cross Section B-B of Basements/Structures Below 588 Elevation to Remain at License Termination.......................................................................... 6-78 Figure 6-7 Cross Section C-C of Basements/Structures Below 588 Elevation to Remain at License Termination.......................................................................... 6-79 Figure 6-8 Cross Section D-D of Basements/Structures Below 588.................................... 6-80 Figure 6-9 Visualization of BFM Conceptual Model............................................................ 6-81 Figure 6-10 RESRAD Parameter Selection Flow Chart.......................................................... 6-82 ATTACHMENT 1 RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis.6-83 ATTACHMENT 2 RESRAD Input Parameters for ZSRP BFM..6-98 ATTACHMENT 3 RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil Sensitivity Analysis6-113 ATTACHMENT 4 RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL.6-124

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-v LIST OF ACRONYMS AND ABBREVIATIONS AF Area Factor ALARA As Low As (is) Reasonable Achievable AMSL Above Mean Sea Level ANL Argonne National Laboratory BFM Basement Fill Model CRA Conestoga Rovers & Associates DCGL Derived Concentration Guideline Level DCF Dose Conversion Factor DUST-MS Disposal Unit Source Term - Multiple Species EPA Environmental Protection Agency FGR Federal Guidance Report FOV Field of View FSS Final Status Survey GW Groundwater HSA Historical Site Assessment HTD Hard-to-Detect IC Insignificant Contributor ISFSI Independent Spent Fuel Storage Installation ISOCS In-Situ Object Counting System LTP License Termination Plan MARSSIM Multi-Agency Radiation Survey and Site Investigation Manual MDC Minimal Detectable Concentration NRC The U.S. Nuclear Regulatory Commission ODCM Off-site Dose Calculation Manual PRCC Partial Rank Correlation Coefficient RASS Remedial Action Support Surveys REMP Radiological Environmental Monitoring Program RESRAD RESidual RADioactive materials ROC Radionuclides of Concern SFP Spent Fuel Pool TEDE Total Effective Dose Equivalent WWTF Waste Water Treatment Facility ZNPS Zion Nuclear Power Station ZSRP Zion Station Restoration Project

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-vi Page Intentionally Left Blank

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-1

6. COMPLIANCE WITH THE RADIOLOGICAL CRITERIA FOR LICENSE TERMINATION 6.1.

Site Release Criteria The site release criteria for the Zion Station Restoration Project (ZSRP) are the radiological criteria for unrestricted release specified in Title 10, Section 20.1402, of the Code of Federal Regulations (10 CFR 20.1402):

Dose Criterion: The residual radioactivity that is distinguishable from background radiation results in a Total Effective Dose Equivalent (TEDE) to an average member of the critical group that does not exceed 25 mrem/yr, including that from groundwater sources of drinking water; and

As Low As (is) Reasonable Achievable (ALARA) Criterion: The residual radioactivity has been reduced to levels that are ALARA.

Chapter 4 describes the methods and results for demonstrating compliance with the ALARA Criterion. This Chapter describes the methods for demonstrating compliance with the Dose Criterion.

6.2.

General Site Description This section provides a general description of the geology and hydrogeology at the Zion Nuclear Power Station (ZNPS) site. Land and groundwater use in the vicinity of site are also summarized. A detailed site description is provided in ZionSolutions TSD 14-003, Conestoga Rovers & Associates (CRA) Report: Conestoga Rovers & Associates (CRA) Report, Zion Hydrogeologic Investigation Report (Reference 6-1).

The ZNPS is located in Northeast Illinois approximately 40 miles north of Chicago, Illinois, and 42 miles south of Milwaukee, Wisconsin. ZNPS is in the extreme eastern portion of the city of Zion, (Lake County) Illinois, on the west shore of Lake Michigan approximately 6 miles NNE of the center of the city of Waukegan, Illinois, and 8 miles south of the center of the city of Kenosha, Wisconsin (see Figure 6-1). The ZNPS owner controlled area is shown in Figure 6-2, with a more detailed view of the Security-Protected Area shown in Figure 6-3.

6.2.1.

Site Geology The Site is underlain by overburden deposits and a regionally extensive sequence of consolidated sedimentary deposits. In descending order, the following overburden stratigraphic units have been identified:

Upper sand unit (also known as the Shallow Aquifer): Dense to very dense granular soils which range in gradation from very fine sand to fine to coarse sand and, which contains some gravel and occasional cobbles and boulders. This unit includes both native and fill sand.

Depth ranges from the ground surface to an elevation of approximately 555 feet Above Mean Sea Level (AMSL).

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-2

Upper silty clay unit: Hard silt, silty clay, clayey silt, and sandy silt which contain some sand and gravel and occasional cobbles and boulders. Depth ranges from approximately 525 feet to 555 feet AMSL.

Lower sand unit: Dense to very dense sands and silty sands which contain some gravel, occasional cobbles and boulders, and layers of hard silty clay, clayey silt, and sandy silt.

Depth ranges from approximately 480 feet to 525 feet AMSL. This unit is discontinuous.

The lower unconsolidated sand unit layer overlies an upper bedrock layer. This upper bedrock layer is the Niagara Dolomite, a consolidated layer of carbonaceous marine sediments laid down in the Silurian Period. It is about 200 feet thick in the vicinity of ZNPS.

6.2.2.

Site Hydrogeology Two aquifer units are present in the overburden material, the upper sand unit and the lower sand unit. These two units are separated by a silty clay unit and together they comprise the shallow unconsolidated aquifer system. The silty clay unit (found under the upper sand unit) is approximately 30 feet thick and extends approximately 15 feet below the deepest structural feature at ZNPS. The silty clay unit acts as an aquitard and prevents vertical migration of groundwater. Therefore the underlying regional Silurian dolomite bedrock aquifer should not be in hydraulic communication with the upper sand unit at ZNPS.

6.2.3.

Area Land Use The ZNPS Facility is located on the shore of Lake Michigan, in the eastern portion of the City of Zion, and adjacent to the Illinois Beach State Park.

The Illinois Beach State Park is located along the Lake Michigan shoreline and is divided into a northern unit and a southern unit, with ZNPS situated between the two units. The Illinois Beach State Park encompasses 4,160 acres and received approximately 2.75 million visitors in 1998.

The Park is considered a natural resource.

The land located to the west of ZNPS is generally undeveloped with a limited number of industrial/commercial facilities present along Deborah Avenue. Residential areas and the City of Zion downtown are located west of the Chicago & Northwestern Railroad, which is west of the Facility. The 2010 census listed the population of Zion as 24,413, with a population density of 2,489 per square mile. Lake Michigan borders the Facility to the east.

6.2.4.

Area Groundwater Use The City of Zion provides municipal water to City residents and the surrounding area. The water is obtained from Lake Michigan by means of an intake pipe located approximately 1 mile north of the Site and extending 3,000 feet into the Lake. The City of Zion municipal code requires all improved properties to be connected to the City's water supply. The code states that it is unlawful for any person to construct, permit or maintain a private well or water supply system within the City which uses groundwater as a potable water supply. There is an exception for some existing wells constructed prior to March 2, 2004. Notwithstanding the fact that current municipal code prohibits construction of residential wells, the conceptual model for dose

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-3 assessment of backfilled basements conservatively includes the installation of a water supply well on the site (see 6.5.3).

6.3.

Basements and Structures to Remain after License Termination (End State)

The End State is defined as the configuration of the remaining below ground buildings, structures, piping and open land areas at the time of license termination.

The Lease Agreement between ZionSolutions and Exelon, Section 8.5 of Exhibit C, titled Removal of Improvements; Site Restoration integral to the Zion Nuclear Power Station, Units 1 and 2 Asset Sale Agreement (Reference 6-2) requires the demolition and removal of all on-site buildings, structures, and components to a depth of at least three feet below grade

[designated as an elevation of 588 foot Above Mean Sea Level (AMSL)]. All contaminated systems, components, piping, buildings and structures above 588 foot elevation will be removed during decommissioning and disposed of as waste. The decommissioning approach for ZSRP also calls for the beneficial reuse of concrete from building demolition as clean fill. Concrete that meets the non-radiological definition of Clean Concrete Demolition Debris and where radiological surveys demonstrate that the concrete meets the 10 CFR 20.1402 criteria for unrestricted use will be used.

In both Containment basements (Unit 1 and Unit 2), all concrete will be removed from the inside of the steel liner above 565 foot elevation leaving only the remaining exposed liner below the 588 foot elevation and the concrete in the area under the vessel including the In-Core Instrument Shaft leading to the under vessel area (designated as the Under-Vessel area), and the structural concrete outside of the liner. In the Auxiliary and Turbine Building basements, all internal walls and floors will be removed, leaving only the reinforced concrete floors and outer walls of the building structures. For the Fuel Handling Building, the only portion of the structure that will remain is the lower 12 feet of the Spent Fuel Pool (SFP) below the 588 foot elevation and the concrete structure of the Fuel Transfer Canals after the steel liners have been removed. There are five additional below ground structures that will remain, including the lower concrete portions of the Waste Water Treatment Facility (WWTF), Crib House/Forebay, Main Steam Tunnels, Circulating Water Intake Piping and Circulating Water Discharge Tunnels. The basements and structures that will remain at license termination as part of the End State are listed in Table 6-1. Figure 6-4 provides a simple plan view of the End State. A series of four cross-sections showing elevation views of the basements and structures to remain is provided in Figures 6-5 to 6-8.

The End State will also include a range of buried pipe, embedded pipe and penetrations. For the purpose of this License Termination Plan (LTP), buried pipe is defined as pipe that runs through soil, embedded pipe is defined as pipe that runs vertically through a concrete wall or horizontally through a concrete floor, and a penetration is defined as a pipe (or remaining pipe sleeve or concrete if the pipe is removed) that traverses a wall and is cut on both sides of the wall. The list of penetrations and embedded pipe to remain is provided in ZionSolutions TSD 14-016, Description of Embedded Piping, Penetrations and Buried Piping to Remain in Zion End State (Reference 6-3). The list of end-state embedded pipe, buried pipe and penetrations presented in Attachment F to TSD 14-016 is intended to be a bounding end-state condition. No pipe that is not listed in Attachment F will be added to the end-state condition however, pipe can be removed from the list and disposed of as waste.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-4 Table 6-1 Basements and Below Ground Structures included in the ZNPS End State Basement/Structure Material remaining Lowest Internal Elevation (feet AMSL)

Unit 1 Containment Building Steel Liner over Concrete 568 Unit 2 Containment Building Steel Liner over Concrete 568 Auxiliary Building Concrete 542 Turbine Building Concrete 560 Crib House and Forebay Concrete 552 WWTF Concrete 577 Spent Fuel Pool Concrete 576 Main Steam Tunnels (Unit 1 and Unit 2)

Concrete 570 Circulating Water Intake Piping Steel Pipe (Site) 552/(Lake) 543 Circulating Water Discharge Tunnels Concrete (Site) 552/(Lake) 543 There is limited potential for contaminated surface or subsurface soil to be present at ZNPS based on the findings of the Zion Station Historical Site Assessment (HSA) (Reference 6-5) and the results of extensive characterization performed in 2013. The results of the characterization surveys are summarized in Chapter 2 of this LTP. There has been no groundwater contamination identified by the groundwater monitoring program at ZNPS. The monitoring program and results are described in the TSD 14-003. The groundwater monitoring results are summarized in LTP Chapter 2, section 2.3.6.5.

After all demolition, remediation and backfill is completed, the 10 CFR Part 50 license will be reduced to the area around the Independent Spent Fuel Storage Installation (ISFSI) and the site will be transferred back to Exelon under the 10 CFR Part 50 license.

6.4.

Dose Modeling Overview Dose modeling is performed to demonstrate that remaining residual radioactivity does not result in a dose exceeding the 25 mrem/yr criterion. The Average Member of the Critical Group (AMCG) is assumed to be the Resident Farmer. This section provides a general overview of the dose modeling approach.

There are four potential sources of residual radioactivity that are categorized as follows for the purpose of dose modeling; backfilled basements, buried pipe, soil, and groundwater. As noted above, there is no indication that significant contamination is currently present in surface or

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-5 subsurface soil or will be present in the End State. The potential for groundwater contamination is also very low but groundwater dose conversion factors are included as a contingency. The dose from each of the four sources will be summed as applicable.

The backfilled basement dose includes the dose from structure surfaces (wall and floors),

embedded pipe, and penetrations in the applicable basement. The dose margin applied to clean concrete fill will also be added to the applicable basement.

An overview of the dose assessment methods for the four sources, and embedded pipe and penetrations, is provided below. Detailed descriptions are provided in subsequent sections.

6.4.1.

Backfilled Basement Structure Surfaces The dose model for backfilled basements and structures to remain below 588 foot elevation at ZNPS (which are generally referred to as Basements in this LTP Chapter) is designated as the Basement Fill Model (BFM). The BFM calculates the annual dose to the AMCG from surface and volumetric residual radioactivity remaining in the basement and structures listed in Table 6-1.

The End State Basements will be comprised of steel and/or concrete structures which will be covered by at least three feet of clean soil and physically altered to a condition which would not realistically allow the remaining structures, if excavated, to be occupied. The exposure pathways in the BFM are associated with residual radioactivity in floors and walls that is released through leaching into water contained in the interstitial spaces of the fill material. The BFM assumes that the inventory of residual radioactivity in a given building is released either instantly or over time by diffusion, depending on whether the activity is surficial or volumetric, respectively.

The activity released into the fill water will adsorb onto the clean fill, as a function of the radionuclide-specific distribution coefficients, resulting in equilibrium concentrations between the fill and the water. Consequently, the only potential exposure pathways after backfill, assuming the as-left geometry, are associated with the residual radioactivity in the water contained in the fill.

A water supply well is assumed to be installed within the fill of the Basement. The well water is then used for drinking, garden irrigation, pasture/crop irrigation, and livestock water supply in the Resident Farmer scenario.

The BFM is implemented using two computational models. The Disposal Unit Source Term -

Multiple Species (DUST-MS) model is used to calculate the maximum water concentrations in the fill material of each basement for a given inventory of residual radioactivity (pCi/L per mCi).

The RESidual RADioactive materials (RESRAD) v7.0 model is used to determine the dose to the Resident Farmer as a function of the water concentration (mrem/yr per pCi/L). BFM Groundwater (GW) Dose Factors are then calculated for each Basement and each Radionuclide of Concern (ROC) by combining the results of the two models with units of mrem/yr per mCi total inventory.

The BFM also includes the dose from drilling spoils that are brought to the surface during the well installation, which is assumed to be at the time of maximum projected future groundwater concentrations. The drilling spoils are assumed to be comprised of fill material containing residual radioactivity at the maximum equilibrium concentrations. Any activity remaining in the

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-6 concrete is also included in the drilling spoils source term. BFM Drilling Spoils Dose Factors are also calculated in units of mrem/yr per mCi total inventory.

The final outputs of the BFM are the Basement Derived Concentration Guideline Levels (DCGL), in units of pCi/m2, which are calculated using the BFM GW and BFM Drilling Spoils Dose Factors. The DCGLs for basement structure surfaces are calculated separately for the GW and Drilling Spoils scenarios and for the summation of both scenarios. The individual Basement Scenario DCGLs for structure surfaces are defined as DCGLBS and represent a dose of 25 mrem/yr for each scenario individually. The basement summation DCGL for basement structure surfaces includes the dose from both the GW and Drilling Spoils scenarios and represents a dose of 25 mrem/yr from both scenarios combined. The summation DCGL for basement structure surfaces is designated as the DCGLB and is used during FSS to demonstrate compliance (equivalent to the DCGLW as defined in MARSSIM). The DCGLs are radionuclide-specific concentrations that represent the 10 CFR 20.1402 dose criterion of 25 mrem/yr and are calculated for each ROC and each backfilled Basement.

Basement DCGLB values were calculated for each of the Basements listed in Table 6-1. The Circulating Water Discharge Tunnels were accounted for by adding the surface area (and corresponding source term) to the Turbine Basement during the DCGL calculation (section 6.6.8). The Circulating Water Intake Piping was accounted for by adding the surface area to the Crib House/Forebay Basement during the DCGLB calculations. Therefore, the DCGLB values calculated for the Turbine Basement also apply to the Circulating Water Discharge Tunnels and the DCGLB values for the Crib House/Forebay also apply to the Circulating Water Intake Piping.

The Steam Tunnel surface area and volume were included with the Turbine Basement in the calculation of BFM Dose Factors and DCGLs. The Turbine Basement DCGLB values therefore also apply to the Steam Tunnel. Note that there is expected to be minimal residual radioactivity in the Steam Tunnels, Circulating Water Intake Piping and Circulating Water Discharge Tunnels.

6.4.2.

Soil Derived Concentration Guideline Levels were developed for residual radioactivity in surface and subsurface soil that represent the 10 CFR 20.1402 dose criterion of 25 mrem/yr. A DCGL was calculated for each ROC.

Two soil DCGLs were calculated, surface soil (DCGLSS) and subsurface soil (DCGLSB) that are defined by the assumed thickness of the soil column from the surface downward. Surface soil is defined as that contained in a 0.15 m depth from the surface. Subsurface soil is defined as that contained in a 1 m depth of soil from the surface. These definitions apply to a continuous soil column from the surface downward. There is no expectation of subsurface contamination in a geometry comprised of a clean soil layer over a contaminated soil layer at depth.

The subsurface soil DCGL, which is based on a 1 m soil depth, can conservatively be applied to any soil depth greater than 0.15 m and less than 1 m. In the unlikely event that geometries are encountered during continuing characterization or during FSS that are not bounded by the 0.15 m and 1 m soil thicknesses, the discovered geometries will be addressed by additional modeling.

The U.S. Nuclear Regulatory Commission (NRC) will be notified if additional modeling is required.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-7 Standard methods for RESRAD parameter selection and uncertainty analysis are used in accordance with guidance in NUREG-1757, Volume 2, Revision 1 Consolidated Decommissioning Guidance - Characterization, Survey, and Determination of Radiological Criteria (Reference 6-6). The AMCG for soil is the Resident Farmer.

6.4.3.

Buried Piping Buried pipe is defined as pipe that runs through soil. The critical group for the buried piping dose assessment is the Resident Farmer.

The buried pipe DCGLs (DCGLBP), in units of dpm/100cm2, are determined for two scenarios; assuming that all pipe is excavated and assuming that all pipe remains in situ. Although unrealistic, for the purpose of the bounding modeling approach used, the dose from the two scenarios is summed to determine the DCGLBP. RESRAD was used to calculate DCGLBP for both the excavation and in situ buried pipe scenarios using the parameters developed for soil modified as necessary for the buried pipe source term geometry. Details on dose assessment methods are provide in section 6.12. A brief overview of scenario assumptions is provided below.

The excavation scenario assumes that all buried pipe is excavated after license termination and all activity on the internal surfaces of the pipes is instantly released and mixed with surface soil.

The in situ scenario assumes that all of the buried piping remains in the as-left condition at the time of license termination and that all activity is instantly released to adjacent soil. Two separate in situ calculations were performed. The first calculation assumes that all pipes are located at 1 m below the ground surface in the unsaturated zone and the second assumes that all pipes are located in the saturated zone. The lowest in situ DCGL from either the 1m deep unsaturated or saturated scenario was assigned as the in situ DCGLBP.

6.4.4.

Embedded Piping Embedded pipe is defined as pipe that runs vertically through concrete walls or horizontally through concrete floors and is contained within a given building. The release pathway for the residual radioactivity in embedded piping is into the basement where the piping is contained.

The dose from embedded piping is summed with the dose from the wall and floor surfaces of the basement that contains the embedded pipe (see section 6.12.9). A DCGL, in units of pCi/m2, was calculated for each embedded pipe survey unit (DCGLEP). To eliminate the potential for activity in embedded pipe to result in the release of radioactivity that could potentially result in higher concentrations than predicted by the BFM, remediation and grouting action levels were established (see LTP Chapter 5, section 5.5.5). However, the dose from embedded pipe will be calculated using the DCGLEP values in order to accurately account for the dose.

6.4.5.

Penetrations A penetration is defined as a remaining system pipe (or the metal sleeve if the system pipe is removed, or concrete if the sleeve is removed or no sleeve was present) that runs through a concrete wall and/or floor, between two buildings, and is open at the wall or floor surface of each building. A penetration could also be a pipe that runs through a concrete wall and/or floor and

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-8 opens to a building on one end and the outside ground on the other end. The levels of residual radioactivity in the majority of penetrations is expected to be low.

Penetrations are divided into separate survey units depending on which basements the penetrations interface with. A DCGL, in units of pCi/m2, was calculated for each penetration survey unit (DCGLPN) assuming that the residual radioactivity is released to both basements(s) that the penetrations interface. The DCGLPN calculation conservatively assumes that 100% of the penetration source term is simultaneously released to both basements.

To eliminate the potential for activity in penetrations to result in the release of radioactivity that could potentially result in higher concentrations than predicted by the BFM, remediation and grouting action levels have been established (see LTP Chapter 5, section 5.5.5). However, the dose from penetrations will be assigned based on the calculated DCGLPN values in order to accurately account for the dose. The dose from penetrations is summed with the dose from the wall and floor surfaces of both basements that the penetration interface (see section 6.12.9).

6.4.6.

Alternate Scenarios Several alternate scenarios for land use after backfill were qualitatively considered including industrial use, recreational use (i.e., parkland), and residential use without a water supply well or onsite garden. The Resident Farmer scenario, with onsite well is clearly a very conservative, bounding scenario relative to the alternatives.

The BFM and the alternate scenarios considered above are based on the as left geometry of the residual contamination in the backfilled Basements. Two additional low probability alternate scenarios were considered that included changes to the as left backfilled geometry. The first entails construction of a basement to the Resident Farmer house within the fill material. Note that the assumed three meter depth of the basement excavation is insufficient to encounter fill material potentially containing residual radioactivity (resulting from leaching of residual radioactivity from surfaces after backfill) assuming the Basement is not constructed within the saturated zone. However, a simple check of direct radiation dose to the resident was conducted to confirm the expectation that the dose would be negligible.

The second alternate scenario that includes disturbance of the as-left geometry considers a very unlikely assumption of a large-scale excavation of the backfilled structures after license termination. The potential doses from large scale excavation were checked by averaging the hypothetical maximum total activity corresponding to 25 mrem/yr in the BFM over the mass of the basement concrete and fill. The average concentrations were compared to the soil concentrations equivalent to 25 mrem/yr based on an industrial use scenario which was assumed to be the only future use that would justify large scale excavation of fill and concrete located deep within the saturated zone.

A third alternate scenario was evaluated which assumed that the drill for a water well encounters penetrations, embedded pipe, and basement surfaces assuming that no activity is released to the fill. The activity in the penetration, embedded pipe or basement surface that is captured by the drill is assumed to be brought to the surface in the drilling spoils. Two receptors were evaluated; the resident farmer and a worker.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-9 6.5.

Basement Fill Conceptual Model This section describes in detail the BFM conceptual model, including the source term, ROC, future land use and exposure scenario, AMCG, and exposure pathways. The BFM is used to calculate dose to the AMCG from residual radioactivity in the backfilled, below ground Basements to remain at the time of license termination. The list of Basements to remain is provided in Table 6-1. The computational model used to implement the conceptual model is described in section 6.6.

6.5.1.

Source Term The source term for the BFM is the residual radioactivity, surface plus volumetric, remaining in each of the Basements at the time of license termination. The source term includes residual radioactivity in wall and floor concrete, or steel liner in the case of the Containment Basements, as well as in embedded piping and penetrations that are contained in or interface with a given basement. Embedded pipe and penetrations are treated as separate survey units within the applicable basement that release activity into the basement fill in the same manner as activity from walls and floors (see sections 6-13 and 6-14). The embedded pipe and penetration source terms are accounted for by adding the dose from the embedded pipe and penetration survey units to the dose from the applicable basement wall and floor survey unit. The total dose from all three sources within a given basement must be less than 25 mrem/yr. See section 6.17.1 for discussion of the process for summing the dose from walls/floors, embedded pipe, and penetrations.

LTP Chapter 2 provides detailed characterization data regarding current contamination levels in the Basements. The data is based on concrete core samples obtained at biased locations with high contact dose rates and/or evidence of leaks/spills. The expected source term configuration and radionuclide distribution expected to remain in each Basement, after remediation is completed, is summarized below.

6.5.1.1.

Unit 1 and Unit 2 Containment Building Basements Both Unit 1 and Unit 2 Containment Buildings are comprised of concrete walls and floors with all interior surfaces of the containment shell covered by a 0.25 inch steel liner. The liner on the 565 foot elevation floor is covered by a 30 inch thick layer of concrete. The floor of the Under-Vessel area is located at the 541 foot elevation. A 30 inch layer of concrete is present above the liner in the Under-Vessel area and a 15 inch layer of concrete is on the walls in the Under-Vessel area. The steel liner on walls above the 568 foot elevation and below the 588 foot elevation has surficial contamination with removable contamination levels ranging from less than 1,000 dpm/100cm2 to approximately 10,000 dpm/100cm2 as indicated by operational and routine radiological surveys.

The concrete in the Under Vessel areas is activated. The Bio-shield concrete surrounding the vessel above 568 foot elevation is also activated. Core samples from the Unit 1 Bio-Shield indicate that the concrete was not activated through the entire depth. Core samples from the Under-Vessel areas indicate low concentrations remain in activated concrete at approximately 15 inches deep but activation through the entire depth is not expected. Continuing Characterization of the Under-Vessel concrete is planned (see LTP Rev 1, Chapter 2, section 2.5). Based on the

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-10 results of cores to date, activation of the liner, or the concrete outside of the liner, is not expected.

The source term for the Unit 1 and Unit 2 Containment Building Basement End States will be a surface contamination layer distributed over the floor and wall surfaces of the remaining exposed steel liner. All concrete inside of the liner, with the exception of the concrete in the Under-Vessel area, will be removed and disposed of as waste. Any remaining residual radioactivity on the steel liner is anticipated to be the result of the deposition of airborne activity during operations, commodity removal and during the removal of the contaminated interior concrete.

Dust suppression measures will be enacted during the removal process and settling of residual radioactivity from airborne dust is expected to be minimal. In addition, operational contamination control measures taken after concrete removal will include removal of loose contamination as required for control of airborne radioactivity. As an illustration of the extent of dust required to deposit on surfaces to be of even trivial consequence, a simple calculation was performed. Based on a nominal estimate of the average radioactivity concentration, before remediation, of 240 pCi/g in the containment concrete (contaminated and activated),

approximately 2 g of dust would be required over an area of 100 cm2 to produce surface contamination levels that exceed 1,000 dpm/100cm2.

The analyses of concrete core samples from Containment Basements indicate that the majority of the contamination is Cs-137. Ni-63, Co-60, Sr-90, Cs-134, H-3, Eu-152, and Eu-154 were also detected but at significantly lower abundance (see section 6.5.2 for mixture fractions).

The current Containment Basement inventories are not meaningful as a prediction of End State inventories because the vast majority of the contamination is in the concrete which will be completely removed during decommissioning. However, the radionuclide mixtures from the core data are considered reasonably representative of the End State mixture. In accordance with ZionSolutions TSD 14-019, Radionuclides of Concern for Soil and Basement Fill Model Source Terms (Reference 6-7) the nominal estimate of the inventory that will remain in the End State of each Containment Basement is approximately 1.0E-04 Ci, assuming 1,000 dpm/100cm2 uniformly distributed over the entire interior surface of the remaining exposed liner surface. The activity remaining in the Under Vessel area concrete will be determined through continuing characterization.

6.5.1.2.

Auxiliary Building Basement The source term for the Auxiliary Building Basement End State is contamination in the remaining concrete walls and floors. The Auxiliary Building has no steel liner.

The majority of the remaining End State inventory in the Auxiliary Building Basement will be surface and volumetric contamination in the concrete floor and lower walls of the 542 foot elevation. During the operation of ZNPS, the 542 foot elevation of the Auxiliary Building was routinely flooded with contaminated water, resulting in the contamination of the concrete floor.

There are water marks on the lower walls up to approximately one meter high.

The upper walls above 545 foot elevation will also be contaminated but at significantly lower concentrations than the floors. Upper wall contamination is expected to primarily be in the vicinity of floors that will have been removed during demolition. Loose surface contamination will also be present on remaining concrete surfaces due to the deposition of airborne

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-11 radioactivity generated during operations, commodity removal and the demolition of interior concrete structures. The inventory attributable to surface contamination on walls has not been estimated but is expected to be a small percentage of the total surface and volumetric inventory in the 542 elevation floor and lower walls.

Characterization results indicate that current levels of loose contamination in the 542 elevation floor range from <1,000 dpm/100 cm2 to over 250 mrad/swipe.

Fixed contamination is present at the surface and at depth in the concrete primarily at the 542 foot elevation floor. To illustrate the distribution and depth of contamination, a range of core sample results from gamma spectroscopy analysis is provided here (see Chapter 2, section 2.3.3.2 for more details on core sample mean and distribution). Seventeen core samples were collected from the 542 foot elevation floor. The highest concentrations were found in the first 0.5 inch where Co-60 concentrations averaged 46 pCi/g, with a maximum concentration of 456 pCi/g, and Cs-137 concentrations averaged 3,352 pCi/g with a maximum concentration of 25,100 pCi/g. The highest concentrations are expected to be limited to RHR Pump Rooms that total approximately 20 m2. In some areas, the depth of contamination is greater than 0.5 inches.

For example, in the Unit 1 and Unit 2 Pipe Chase Rooms, Cs-137 concentrations of 530 pCi/g and 1,650 pCi/g were observed at depths of 4 and 5 inches, respectively. Additional cores identified a Cs-137 concentration of 57 pCi/g, at a depth of 2 inches in the central common area, a Cs-137 concentration of 31 pCi/g at a depth of 3.5 inches in the east floor area, and a Cs-137 concentration of 63 pCi/g at a depth of 3 inches in the Unit 1 Equipment Drain Collection Tank and Pump room.

The primary radionuclides by mixture percentage in the Auxiliary Building concrete are Cs-137 and Ni-63 (a non-gamma emitting radionuclide) at 75% and 24%, respectively. Cobalt-60, Sr-90, and Cs-134 were also detected but at significantly lower percentages (see section 6.5.2 for discussion of radionuclide mixture). Based on the results of the concrete core samples taken during characterization, which were biased to the worst-case radiological conditions, the current total inventory, including all radionuclides, in the Auxiliary Building is estimated to be approximately 0.84 Ci (Reference 6-7).

6.5.1.3.

Fuel Handling Building Basement and Transfer Canals The only portion of the Fuel Handling Building Basement that will remain following building demolition is the lower 12 feet (~4 m) of the SFP and Transfer Canals with floor elevations at 576 foot. The steel liner will be removed from both the SFP and the Transfer Canals. After the liners are removed and the underlying concrete exposed, additional characterization surveys will be performed to assess the radiological condition of the underlying concrete pad and remaining pool walls. Contamination is expected below the liner but estimates of the range, distribution and radionuclide mixture cannot be made until characterization is completed. The mixture is expected to be similar to that found in contaminated concrete in the Auxiliary Building in that the predominant radionuclide is expected to be Cs-137.

6.5.1.4.

Turbine Building Basement and Steam Tunnels Characterization surveys have shown that there is currently minimal residual contamination in the structural surfaces of the Turbine Building. Analyses of concrete cores collected from the

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-12 floor of the Turbine Building at 560 foot elevation show the presence of Cs-137 at concentrations greater than Minimal Detectable Concentration (MDC) at two of three sample locations, and only in the first 0.5 inch of concrete. Cs-137 concentrations range from 0.6 pCi/g to 47 pCi/g. In the Steam Tunnels, Cs-137 concentrations in the first 0.5 inch of concrete ranged from 7 pCi/g to 47 pCi/g in Unit 1 and 0.3 pCi/g to 19 pCi/g in Unit 2. At depths greater than 0.5 inch, Cs-137 concentrations were below MDC. No other radionuclides were identified at concentrations exceeding MDC. A nominal inventory estimate assuming 10% of the surface is contaminated at the maximum concentration is 2E-05 Ci.

6.5.1.5.

Remaining Basements Due to access restrictions, characterization was not performed in the remaining Basements, including the Forebay, Circulating Water Intake Piping and Circulating Water Discharge Tunnels. However, based on process knowledge and operational history, minimal or no radioactive contamination is expected in these Basements. Concrete core samples were collected from the Crib House as a part of concrete background studies. Only natural background activity levels were detected.

The Circulating Water Discharge Tunnels were the main authorized effluent release pathway for the discharge of treated and filtered radioactive liquid effluent to Lake Michigan. During plant operations and following shut-down, the liquid effluent release pathway was monitored and the results presented in the annual Radiological Environmental Monitoring Program (REMP) report in accordance with the Off-site Dose Calculation Manual (ODCM). The Unit 2 Circulating Water Discharge Tunnel was used as an authorized effluent release pathway during decommissioning from 6/2013 to 10/2015. The Circulating Water Discharge Tunnels were surveyed as a part of continuing characterization program after effluent release was discontinued (see LTP Chapter 2, section 2.5).

6.5.2.

Radionuclides of Concern NUREG-1757, section 3.3 states that radionuclides contributing no greater than 10% of the dose criterion (i.e., 2.5 mrem/yr) are considered to be insignificant contributors (IC). This 10%

criterion applies to the sum of the dose contributions from the group of radionuclides considered insignificant.

After the group of IC radionuclides was identified and removed from the initial suite of potential radionuclides, the IC dose was accounted for by adjusting the DCGLs for the remaining radionuclides which are designated as the ROC (see section 6.6.8). The IC radionuclides are then excluded from further detailed evaluations. The ROC are included in the source term for detailed dose modeling.

To identify the IC radionuclides and develop the final ROC list, the first step was to develop the initial suite of radionuclides that have a potential of being present.

6.5.2.1.

Potential Radionuclides of Concern and Initial Suite ZionSolutions TSD 11-001, Potential Radionuclides of Concern during the Decommissioning of Zion Station (Reference 6-9) established the basis for an initial suite of potential ROC prior to characterization. Three industry guidance documents were reviewed including

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-13 NUREG/CR-3474, Long-Lived Activation Products in Reactor Materials, (Reference 6-10),

NUREG/CR-4289, Residual Radionuclide Concentration Within and Around Commercial Nuclear Power Plants; Origin, Distribution, Inventory, and Decommissioning Assessment (Reference 6-11) and WINCO-1191, Radionuclides in United States Commercial Nuclear Power Reactors (Reference 6-12). Radionuclide half-lives were obtained from ICRP Publication 38, Radionuclide Transformations - Energy and Intensity of Emissions (Reference 6-13). The review also included the evaluation of 19 post-shutdown waste streams.

Based on the elimination of noble gases, theoretical neutron activation products with an abundance less than 0.01 percent relative to Co-60 and Ni-63 (the prominent activation products identified in ZNPS samples), and radionuclides with half-lives less than two years, an initial suite of radionuclides was selected that were considered to potentially be present during the decommissioning of ZNPS.

After characterization at ZNPS was completed, the results of concrete core sample analyses collected from the Containment Buildings and Auxiliary Building was reviewed in TSD 14-019.

Two radionuclides, Ag-108m and Eu-155 were positively identified in one or more characterization cores and were therefore added to the list of potential radionuclides developed in TSD 11-001. The resulting initial suite of potential radionuclides is provided in Table 6-2.

6.5.2.2.

Radionuclide Mixture for Initial Suite Radionuclides The mixture percentages for the initial suite of radionuclides for Containment and Auxiliary Basement concrete were developed in TSD 14-019 using the results of the core sample analyses.

Several radionuclides in the initial suite were not positively identified in any of the core sample analyses. The mixture percentages for these radionuclides were conservatively determined using the reported MDC values. The mixture percentages for the initial suite are provided in Table 6-2.

The mixture percentage for the non-gamma emitters, or Hard-to-Detect (HTD) radionuclides, were determined by analyzing selected cores from the Containment and Auxiliary Basements that contained the highest radionuclide concentrations based on gamma spectroscopy. The use of cores with higher concentrations was required to ensure that the percentage assigned to HTD radionuclides were not overly influenced by the MDC values which was the only concentration data available for the majority of the HTD radionuclides in the initial suite.

The radionuclide concentrations identified in core samples from the Turbine Building were very low, which is consistent with expectations based on operational history. Given the very limited data available, the direct determination of mixture percentages, particularly from the HTD radionuclides, was not feasible. No characterization data was collected from the Forebay, WWTF, and Circulating Water Intake Piping but the contamination levels, if any, in these Basements are expected to be minimal. Concrete cores were collected in the Crib House as a part of a background study and only natural background activity levels were identified.

Given the lack of available data and the very low levels of residual radioactivity expected to remain, the radionuclide mixture for the Auxiliary Building was considered to be a reasonably conservative mixture for the Turbine Basement, Crib House/Forebay, WWTF, and Circulating Water Inlet Piping.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-14 The mixtures in the Circulating Water Discharge Tunnels and the SFP/Transfer Canals could be somewhat different than the Auxiliary Building due to the sources of potential contamination, i.e., effluent discharge during decommissioning and fuel pool water leaking into the concrete under the liner, respectively. This will be evaluated as a part of the continuing characterization process (see LTP Chapter 2, section 2.5).

However, the mixture in both the Circulating Water Discharge Tunnel and the SFP/Transfer Canal is expected to be primarily Cs-137 as in the other Basements. Therefore, the Auxiliary Basement mixture is considered reasonable for application to these two structures for planning purposes. The mixtures in these two Basements will be reviewed as continued characterization data is collected from these areas (see LTP Chapter 5, section 5.1).

Note that there is essentially no dose impact from uncertainty in the mixture fractions for beta-gamma emitting radionuclides because the FSS will be performed using gamma spectroscopy and compliance with the 25 mrem/yr dose criterion will be demonstrated using actual measured concentrations. The only potential dose impact of mixture uncertainty is therefore limited to the HTD mixture percentages. The dose impact of HTD radionuclides in the BFM is very low as demonstrated by the very low relative dose contribution of HTD radionuclides as discussed below.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-15 Table 6-2 Initial Suite of Potential Radionuclides for ZNPS and Radionuclide Mixture Based on Auxiliary and Containment Concrete Nuclide Containment Auxiliary Percent Activity Percent Activity H-3 0.074%

0.174%

C-14 0.008%

0.044%

Fe-55 0.174%

0.106%

Ni-59 0.156%

0.498%

Co-60 4.675%

0.908%

Ni-63 26.275%

23.480%

Sr-90 0.027%

0.051%

Nb-94 0.178%

0.013%

Tc-99 0.008%

0.016%

Ag-108m 0.282%

0.017%

Sb-125 0.025%

0.017%

Cs-134 0.008%

0.010%

Cs-137 67.582%

74.597%

Eu-152 0.436%

0.017%

Eu-154 0.058%

0.009%

Eu-155 0.018%

0.008%

Np-237 0.000%

0.0004%

Pu-238 0.001%

0.001%

Pu-239 0.000%

0.0005%

Pu-240 0.000%

0.001%

Pu-241 0.007%

0.028%

Am-241 0.007%

0.001%

Am-243 0.000%

0.001%

Cm-243 0.001%

0.0003%

Cm-244 0.001%

0.0003%

Total 100%

100%

6.5.2.3.

Insignificant Dose Contributors and Radionuclides of Concern The relative and actual dose contributions from each radionuclide in the initial suite was calculated to identify the IC radionuclides and remove them from further detailed consideration.

The remaining radionuclides are designated as the ROC. ZionSolutions TSD 14-010, RESRAD Dose Modeling for Basement Fill Model and Soil DCGL and Calculation of Basement Fill Model Dose Factors and DCGLs (Reference 6-14) provides DCGLB and DCGLBS values for the initial suite. Preliminary analyses indicated that the ROC for the Auxiliary Basement were Cs-137, Co-60, Sr-90, Cs-134, and Ni-63. For Containment, the preliminary ROC were the same five radionuclides with the addition of H-3, Eu-152 and Eu-154.

In TSD 14-019, the DCGLB and Drilling Spoils DCGLBS values for the initial suite radionuclides were used to calculate the IC dose percentage and corresponding IC dose (i.e., IC dose

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-16 percentage times 25 mrem/yr) from the removed radionuclides. Five radionuclide mixtures were assessed;

mixture for Containment listed in Table 6-2 (which is considered the best estimate),

mixture for Auxiliary Basement listed in Table 6-2 (which is considered the best estimate),

mixture using the 11 cores from Unit 1 Containment that were analyzed for the full initial suite,

mixture using the 10 cores from Unit 2 Containment that were analyzed for the full initial suite,

mixture using the 6 cores from the Auxiliary Basement that were analyzed for the full initial suite.

The IC dose was also calculated using the actual results (in units of pCi/g) from the individual cores analyzed for the initial suite. The IC dose mean, standard deviation of the mean, and 95%

upper confidence level (UCL) were calculated for individual cores from Unit 1 Containment, Unit 2 Containment and the Auxiliary Basement. The total dose and IC dose from the individual cores were calculated assuming that the core concentrations were uniformly distributed over 100% of wall and floor surfaces of a given basement. In many cases, this hypothetical dose exceeded 25 mrem/yr. The high dose was expected given that the cores were collected from areas with the highest pre-remediation gamma activity. A concentration representing a dose greater than 25 mrem/yr would require remediation. Therefore, the total dose, and corresponding IC dose, for cores exceeding 25 mrem/yr were normalized to 25 mrem/yr to provide a value that represents the percentage of the dose criterion to be consistent with the definition in NUREG-1757, section 3.3. The IC dose from a core with a total dose below 25 mrem/yr was reported with no normalization.

The IC dose (normalized as applicable) was calculated for each core individually and the mean, range, and 95% UCL compared to the IC dose calculated from the mixtures (i.e., dose corresponding to the IC dose percentage times 25 mrem/yr). The individual core IC dose was used to assess variability and inform the selection of the IC percentage assigned to adjust the ROC DCGLs and to ensure the assigned percentage is sufficiently conservative. The results of IC dose calculations based on mixtures are provide in Table 6-3. The IC dose from individual cores is provided in Table 6-4.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-17 Table 6-3 IC Dose from Mixtures Core Data IC Dose mrem/yr (percent of 25 mrem/yr)

IC Dose Drilling Spoils mrem/yr (percent of 25 mrem/yr)

Table 6-2 Mixture Containment (Unit 1 and 2 Combined)

(39 Cores - Initial Suite and Onsite Gamma) 0.13 (0.51%)

0.06 (0.15%)

Table 6-2 Mixture Auxiliary (20 Cores - Initial Suite and Onsite Gamma) 0.33 (1.31%)

0.01 (0.22%)

Unit 1 Containment Mixture (11 Initial Suite Cores) 0.13 (0.51%)

0.08 (0.33%)

Unit 2 Containment Mixture (10 Initial Suite Cores) 0.07 (0.28%)

0.05 (0.22%)

Auxiliary Mixture (6 Initial Suite Cores) 0.33 (1.29%)

0.01 (0.18%)

Table 6-4 IC Dose from Individual Cores (Normalized)

Core Population Individual Core IC Dose Range mrem/yr (Percentage of 25 mrem/yr)

Individual Core IC Dose Mean mrem/yr Individual Core IC Dose 95% UCL mrem/yr Individual Core Total Dose Range(1) mrem/yr Unit 1 Containment (11 cores) 0.06 to 2.01 (0.22% to 8.06%)

0.37 0.66 2.18 to 2,212 Unit 2 Containment (10 cores) 0.02 to 1.03 (0.08% to 4.10%)

0.30 0.48 0.99 to 3,228 Auxiliary (6 cores) 0.27 to 0.73 (1.06% to 2.91%)

0.53 0.63 6.48 to 76.42 (1) Dose from all radionuclides before normalizing to 25 mrem/yr As seen in Table 6-3 and 6-4, the highest IC dose from the five mixtures evaluated was 0.33 mrem/yr (1.31%). The maximum individual core dose, was 2.01 mrem/yr (8.06%) and 0.63 mrem/yr (2.91%) for Containment and the Auxiliary Basement, respectively. The maximum mean and 95% UCL for all individual core results were 0.53 mrem/yr and 0.66 mrem/yr, respectively. From the review of the mean and 95% UCL values in Table 6-4, it is clear that the maximum individual core IC dose of 2.01 mrem/yr (8.06%) is an outlier and not representative of widespread conditions. The individual cores represent a range of contamination conditions, with total dose projections (before normalization) from 0.99 mrem/yr to 3,228 mrem/yr, and are considered representative of the range of conditions that that will be encountered during decommissioning.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-18 To account for any additional, unspecified variability and to provide confidence the HTD analyses performed during continuing characterization will not result in an IC dose exceeding that assigned to adjust the ROC DCGLs, a margin was applied to the IC percentage calculated using the Table 6-2 mixture by increasing the percentage to 5% for the Auxiliary Basement and 10% for the Containment Basement (to account for the single core maximum of 8.06%). The resulting IC dose percentage of 5% and 10% (1.25 mrem/yr and 2.5 mrem/yr) will be used to adjust the ROC DCGLs (Basement, Groundwater Scenario and Drilling Spoils Scenario) for the Auxiliary Basement and Containment, respectively, to conservatively account for the IC dose.

These values exceed any mixture IC dose, individual core IC dose, or individual core 95% UCL IC dose found in Tables 6-3 and 6-4 and is therefore considered a bounding value.

The final ROC for Containment and the Auxiliary Basement are provided in Table 6-5. As discussed above, the Table 6-2 mixture is considered the most representative. Therefore, the ROC and IC dose percentages in Table 6-5 are considered best estimates and are provided for information and comparison to the selected IC percentage of 5% and 10% that will be used to adjust DCGLs for the Auxiliary Basement and Containment, respectively. As shown in Table 6-5, the IC dose percentages for the Table 6-2 mixture are 0.51% and 1.31% for Containment and Auxiliary Building, respectively. The vast majority of dose is from Cs-137 at 97%. The next highest dose contributor was Co-60 at 1.7%. All radionuclides, except Cs-137 could be included as insignificant contributors and eliminated in accordance with the 10% criterion. However, for conservatism and, in anticipation of potential positive ISOCS results during FSS, the low dose significant gamma emitters Co-60 and Cs-134 are retained as ROC. Sr-90 and Ni-63 are HTD radionuclides that are low dose contributors in the Auxiliary Basement but do have some, albeit low, potential for positive detection during FSS and are also retained as ROC. The Containment ROC includes Eu-152, Eu-154 and H-3 because of their potential for being present in activated concrete, not due to their dose contribution which is less than 0.1% total.

As discussed above, the Auxiliary Basement ROC and selected IC percentage of 5% for adjusting ROC DCGLs will also be applied to all other Basements with the possible exception of the SFP/Transfer Canal depending on the results of continuing characterization.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-19 Table 6-5 Zion Radionuclides of Concern for Containment and Auxiliary Basements.

Radionuclide Containment Auxiliary Percent Activity Percent Annual Dose2 Percent Activity Percent Annual Dose(2)

H-3(1) 0.074%

0.017%

NA NA Co-60 4.675%

1.669%

0.908%

0.783%

Ni-63 26.275%

0.366%

23.480%

0.270%

Sr-90 0.027%

1.072%

0.051%

0.742%

Cs-134 0.008%

0.015%

0.010%

0.039%

Cs-137 67.582%

96.269%

74.597%

96.959%

Eu-152(1) 0.436%

0.067%

NA NA Eu-154(1) 0.058%

0.010%

NA NA IC Dose Percentage (Table 6-2 Mixture) 0.864%

0.512%

0.954%

1.313%

Total 100%

100%

(1) H-3, Eu-152 and Eu-154 are activation products and therefore applicable to Containment Building only (2) Percent annual dose and IC dose percentage based on best estimate mixture in Table 6-2 for information. IC percentages of 5% and 10% will be used for ROC DCGL adjustment for Auxiliary and Containment Basements, respectively, to provide additional margin.

6.5.2.4.

Radionuclide Ratios for Application to Surrogate Approach The FSS for basement surfaces will be performed using ISOCS gamma spectroscopy. Three radionuclides that are not gamma emitters are included as ROC, i.e., Sr-90 and Ni-63 for the Auxiliary Basement and Sr-90, Ni-63 and H-3 for Containment. As discussed in LTP Chapter 5, the Sr-90, Ni-63 and H-3 concentrations will be accounted for using a surrogate approach during FSS. The ratios of Sr-90/Cs-137, Ni-63/Co-60 and H-3/Cs-137 are required to implement the surrogate approach.

The radionuclide ratios were calculated in TSD 14-019 by calculating the ratios of Sr-90/Cs-137, Ni-63/Co-60 and H-3/Cs-137 within each individual core analyzed for the initial suite. Ratios were calculated separately for Containment and the Auxiliary Basement. The mean, maximum, and 95% UCL of the individual core ratios were calculated. The 95% UCL was conservatively calculated using the standard deviation of the individual results as opposed to the standard deviation of the mean. Table 6-6 provide the results. The maximum individual ratios are all higher than the 95% UCL and will be used in the surrogate calculations during FSS unless different values are justified by the results of continuing characterization or FSS HTD analysis (see LTP Chapter 5 section 5.2.11).

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-20 Table 6-6 Radionuclide Ratios from Concrete Cores Radionuclide Ratio Containment Auxiliary Basement Mean Maximum 95% UCL Mean Maximum 95% UCL Sr-90/Cs-137 0.002 0.021 0.010 0.001 0.002 0.002 Ni-63/Co-60 30.62 442 194 44.14 180.45 154.63 H-3/Cs-137 0.21 1.76 0.96 NA NA NA 6.5.3.

Critical Group and Exposure Scenario The critical group for the BFM dose assessment is the Resident Farmer. A well is assumed to be installed onsite (in the center of the Basement with the highest projected future groundwater concentrations), which supplies drinking water, water for livestock and irrigation water for a garden and pasture/crop land. The Resident Farmer is considered a bounding exposure scenario (as defined in NUREG-1757). A simple visualization of the BFM conceptual model is provided in Figure 6-9.

The Reasonably Foreseeable Scenario, which is defined in NUREG-1757 as a land use scenario that is likely within the next 100 years, could be justified as not including an onsite water well which is prohibited by local municipal code (see section 6.2.4). Municipal water in the vicinity of ZNPS is supplied by Lake Michigan, which is expected to be a viable source for hundreds of years. In addition, Resident Farmer land use, with or without a well, would also be unlikely for a minimum of 100 years after license termination considering current land use and zoning in the area. Any type of residential use is essentially non-credible while the ISFSI is present.

Current zoning at the ZNPS is heavy industrial use. The City of Zion, Official Zoning Map City of Zion March 2011 (Reference 6-15) contains no agricultural use areas anywhere in the city.

In addition, a 2012 report by the United States Department of Agriculture, Custom Soil Resources Report Lake County Illinois (Reference 6-16), classified the soil at ZNPS as Category 3, which is defined as soils with severe limitations that reduce the choice of plants or require special conservation practices, or both. While the zoning and soil classification does not preclude a resident garden, the use of the land for raising livestock such as beef and dairy cattle during the next 100 years could justifiably be categorized as a less likely but plausible scenario (as defined in NUREG-1757, Table 5.1). Consistent with this definition, it would be reasonable to not include livestock in the compliance dose assessment.

Using a simple assumption that the Resident Farmer well drilling scenario would not occur on the site for at least the first 100 years after license termination, if at all, the BFM dose would be reduced by about a factor of ten based on the radioactive decay of Cs-137, which is the predominant radionuclide. Assuming that residential occupancy does occur after license termination, eliminating the livestock pathway and retaining the onsite well, resident garden, etc., would reduce the dose by approximately 60%. Notwithstanding all of the above, the BFM applies the Resident Farmer land use to ensure that the critical group and exposure scenario produce a conservative and bounding compliance dose calculation.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-21 6.5.4.

Exposure Pathways The BFM applies to the backfilled Basements which will have a minimum of 3 feet cover and approximately 3 m of clean fill above the potential source term zone as defined by the equilibrium water level in the backfilled Basements. The equilibrium water level is conservatively assumed to be at the natural water table elevation of 579 foot. Therefore, the dose from the water-independent exposure pathways is negligible. Nonetheless, all Resident Farmer exposure pathways, water-dependent and water-independent are included in the model to verify this assumption. The aquatic pathway from an onsite pond is not credible due to engineering and cost issues of construction and proximity to Lake Michigan which negates any foreseeable need (TSD 14-003).

The Resident Farmer Scenario includes the following exposure pathways:

Direct exposure to external radiation

Inhalation dose from airborne radioactivity

Ingestion dose from the following pathways;

- Plants grown with irrigation water from onsite well,

- Meat and Milk from livestock consuming fodder from fields irrigated with onsite well water and consuming water from onsite well,

- Drinking water from onsite well,

- Soil ingestion.

Direct exposure, inhalation dose and ingestion dose from contaminated drilling spoils brought to the surface during installation of the onsite well into the fill material.

The last bullet is not a standard Resident Farmer exposure pathway as described in NUREG/CR-5512, Volume 1, Residual Radioactive Contamination from Decommissioning Parameter Analysis (Reference 6-17) or as contained in RESRAD. However, the BFM Resident Farmer scenario is predicated on the well being installed into the basement fill which will generate drilling spoils. Assuming a well is drilled, exposure to the spoils that are brought to the surface is a potential exposure pathway. The potential dose contribution from this pathway was checked in screening assessments and found to be greater than 10% of the total BFM dose in some cases (see section 6.6.7). Therefore, the pathway was included in the BFM.

The well water dependent BFM exposure pathways are not applicable to the SFP due to the elevation of the SFP floor being at the 576 foot elevation (see Table 6-1), which is only three feet below the water table elevation of 579 foot. Operating water well in an area with only three feet of available water is considered a land use that because of physical limitations could not occur and is therefore implausible as defined in Table 5.1 of NUREG-1757. However, this would not preclude a well driller from inadvertently picking a location above the SFP as a potential well location and then rejecting the location based on low water level. Therefore, for the SFP/Transfer Canal Basement, the pathways resulting from well water are not applicable, but the drilling spoils pathway is applicable and will be applied in the BFM assessment. However, the potential contribution of the SFP/ inventory to a well water pathway will be considered by adding the SFP/Transfer Canal surface area to the Containment and Auxiliary Basement surface

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-22 areas during the DCGL calculation (see section 6.6.8). Adding the surface area to the DCGL calculation corresponds to adding the inventory. This addition is necessary because the SFP/Transfer Canal will be hydraulically connected to the Containment Basements through the Fuel Transfer Tubes and to the Auxiliary Basement through the opening in the wall between the Transfer Canal and the Auxiliary Basement that was created to facilitate decommissioning.

The same argument regarding implausibility of well operation that was applied to the SFP/Transfer Canal could also be applied to the WWTF, which has a floor that is only two feet below the site groundwater levels and an internal Basement volume of 144 m3. However, the WWTF is an isolated structure with no connections to other Basements and therefore, the inventory cannot credibly be added to other Basements to conservatively account for the well water exposure pathways. Therefore, the water well pathways are applied in the BFM for the WWTF as a simple, bounding approach.

6.6.

Basement Fill Computation Model 6.6.1.

DUST-MS Model The initial environmental transport pathway for the Resident Farmer scenario is the release of radioactivity from Basement concrete (or steel liner surfaces for Containment Basements) to water in the interstitial space of the fill material. The water concentrations in the Basements are calculated using the DUST-MS computer code. The methods and results are summarized here and described in detail in ZionSolutions TSD 14-009, Brookhaven National Laboratory Report (BNL), Evaluation of Maximum Radionuclide Groundwater Concentrations for Basement Fill Model, Zion Station Restoration Project (Reference 6-18). The water concentrations calculated by DUST-MS were used in conjunction with RESRAD modeling results (see section 6.6.3) to calculate BFM Dose Factors (see section 6.6.8).

The DUST code was originally developed through support from the NRC in 1992. Subsequent development of the code led to the multiple species (MS) version. DUST-MS was used by the NRC to develop guidance on performance assessment for low-level waste disposal and has been accepted for use in LTPs for other power reactor sites.

To calculate the maximum water concentrations, the rate of radionuclide release from concrete the source term to the fill is required. Diffusion controlled release is assumed for Basements with volumetric contamination (i.e., Auxiliary and SFP/Transfer Canal) and instant release is assumed for the remaining Basements where contamination is predominantly on or near the structure surfaces.

After release, the residual radioactivity is assumed to mix instantly with the water the Basements.

The concentrations are calculated for each Basement independently. The only mechanism to reduce the water concentration is sorption onto the fill material. The water concentration for this model can be calculated using Equation 6-1.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-23 Equation 6-1

where:

C = concentration in water (pCi/L)

I = inventory (pCi)

V = Basement mixing volume (L)

= effective porosity

= bulk density (g/cm3)

Kd = distribution coefficient (cm3/g)

Although simple spreadsheet calculations can be performed to determine equilibrium water concentrations for the Basements with instant release, DUST-MS is used to simulate diffusion controlled release for Basements with volumetrically contaminated concrete. In addition, a sensitivity analysis was conducted of the impact of alternate well placement on groundwater concentrations, assuming transport to a well located outside of the Basements (as opposed to the being placed in the Basement fill) which also requires the use of DUST-MS. Therefore, all calculations have been performed with DUST-MS to maintain consistency and for ease of calculation and reporting The water concentrations are calculated separately for each Basement with no assumption of mixing between buildings. This is conservative given that there will be several open penetrations between the Basements after piping is removed that will provide hydraulic connectivity between the Basements. ZionSolutions TSD 14-032, Conestoga Rovers &

Associates Report, Simulation of the Post-Demoltion Saturation of Foundation Fill Using a Foundation Water Flow Model (Reference 6-19) describes the remaining penetrations and the projected equilibrium water levels in the Basements. Mixing and flow of water between Basements will occur, primarily between the Auxiliary, Containment and Turbine Basements.

The maximum equilibrium water concentrations are conservatively calculated for the worst case individual Basement (expected to be the Auxiliary Basement) assuming no mixing.

Based on current demolition plans, there will be no connection between the Basements and surrounding groundwater. A number of pipes that penetrate the Turbine Basement walls and enter the outside ground will be removed from both sides of the Basement walls or remain in the ground outside of the Turbine basement. This will leave a number of penetrations open to the outside ground, primarily on the east side of the Turbine Basement. However, none of these open penetrations are below the water table (579 foot elevation). There are two 48 inch diameter Service Water Supply Lines that run from the 549 foot elevation in the Auxiliary Building, to the ground east of the Turbine Basement which will be cut above the 579 foot elevation in the ground and will be filled with grout or sealed in another manner. There are also a number of small diameter buried pipes that penetrate Basements below the 579 foot elevation, primarily in the Auxiliary Basement. These are designated as Building to Ground Penetrations Buried Pipe in TSD 14-016. Most of these pipes are currently planned to be cut in the ground above the 579 foot elevation and therefore above the average groundwater elevation. A few are listed as terminating in the ground below 579 foot elevation. To eliminate uncertainty regarding water ingress or egress through these small diameter penetrations that are connected to buried pipe, all

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-24 of the penetrations in this category that enter a basement below 579 foot elevation will be grouted regardless of what elevation the buried pipe is cut within the ground. Grouting provides additional assurance that the End State configuration provides no route for groundwater ingress into the Basements, leaving only rainwater infiltration as the source of water in the fill. TSD 14-032 estimated that it will take approximately 28 years to reach an equilibrium water level across all Basements, considering rainwater infiltration rates and existing penetrations between Basements. The DUST-MS model assumes that the Basements are full of water immediately after license termination and capable of supporting a residential well, which is a conservative assumption.

6.6.1.1.

Parameter Selection For DUST-MS modeling, the initial source term in each Basement is nominally assumed to be 1 pCi/m2 uniform activity over all walls and floor surfaces below 588 foot elevation. The inventory corresponding to this activity (1 pCi/m2 multiplied by the surface area in a given Basement) is the value used for the equilibrium calculations. However, it is important to note that the value of the assumed inventory in each Basement is immaterial because the DUST-MS modeling results are used to generate unitized Groundwater Concentration Factors in units of pCi/L per mCi. The DUST-MS results will be used in conjunction with the RESRAD results (see section 6.6.3) to calculate BFM Dose Factors in units of mrem/yr per mCi. The BFM Dose Factors are then used to calculated DCGLs, in units pCi/m2 (see section 6.6.8).

The equilibrium calculation for released activity is simple as shown in Equation 6-1 and includes limited input parameters. The selected model parameters are listed in Tables 6-7 and 6-8.

Table 6-7 General Parameters for DUST-MS Modeling Parameter Selected Value Kd Table 6-5 (Nuclide Dependent)

Porosity 0.25 Bulk Density 1.5 g/cm3 Basement Mixing Volume Table 6-6 (Basement Dependent)

Table 6-8 Distribution Coefficients for DUST-MS Modeling Radionuclide Basement Fill Kd (cm3/g)

Co-60 223 Ni-63 62 Sr-90 2.3 Cs-134 45 Cs-137 45 Eu-152 95 Eu-154 95 The specific composition of the backfill has not yet been determined but is expected to be some combination of sand and debris resulting from building demolition that is designated for beneficial reuse as clean hard fill. The ratios of sand and demolition debris are not known and therefore, the bulk density and porosity not known with certainty. ZionSolutions TSD 14-006, a report by Conestoga Rovers & Associates, Evaluation of Hydrological Parameters in Support

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-25 of Dose Modeling for the Zion Restoration Project, (Reference 6-20) calculates site-specific values for the porosity and density of local soil. The results were 0.35 and 1.8 g/cm3, respectively. Inspection of Equation 6-1 shows that calculated water concentrations are inversely proportional to porosity and density. Therefore, a conservative bulk density of 1.5 g/cm3 and porosity of 0.25 were selected for the DUST-MS parameters. With any of the fill materials, it is unlikely that packing of the material would result in porosity below 0.25.

The distribution coefficients (Kd) are important parameters in the calculation of equilibrium concentrations. As shown in Equation 6-1, water concentration varies inversely with Kd.

Consequently, lower Kd values will result in higher projected future water concentrations.

ZionSolutions TSD 14-004, a report by Brookhaven National Laboratory, Recommended Values for the Distribution Coefficient (Kd) to be used in Dose Assessments for Decommissioning the Zion Nuclear Power Plant, (Reference 6-21) reviewed Kd values from three sources:

Data Sources for selection of DUST-MS Modeling distribution coefficients:

literature values,

site-specific Kd analyses performed by Brookhaven National Laboratory as documented in two reports, ZionSolutions TSD 14-017, Sorption (Kd) Measurements on Cinder Block and Grout in Support of Dose Assessments for Zion Nuclear Station Decommissioning (Reference 6-22), and ZionSolutions TSD 14-020, Sorption (Kd) measurements in Support of Dose Assessments for Zion Nuclear Station Decommissioning (Reference 6-23), and

the 25th percentile values of the Kd distributions provided in NUREG/CR-6697, Development of Probabilistic RESRAD 6.0 and RESRAD-BUILD 3.0 Computer Codes (Reference 6-24).

In selecting values from literature, environmental conditions with high pH (cement sorption data) as well as typical environmental soil sorption data were considered due to the anticipated presence of concrete and cinderblock demolition debris in the fill. For conservatism the minimum values from all of these sources were selected. For nuclides with measured site-specific Kd values, the lowest measured Kd in any potential backfill material or soil was selected.

6.6.1.2.

Mixing Volume The water concentrations calculated by DUST-MS are inversely proportional to the assumed mixing volume which differs for each Basement as a function of the building geometry and distance from the floor to the assumed water elevation in the Basements. Section 6.5.1 describes the source terms and remaining structural configuration of the Basements.

The projected equilibrium water elevation in the Basements was evaluated in TSD 14-032. The water level is driven by the location, elevation and size of existing penetrations between the Basements and between the Basements and outside ground. The current decommissioning approach does not include making additional perforations through Basement walls other than between the SFP and the Transfer Canals. Given these conditions, the equilibrium water level in the Basements was projected to be at the 586 foot elevation. A number of options are presented in TSD 14-032 for perforating the basements to keep water levels at approximately 579 foot elevation. ZSRP has selected Scenario 3 from TSD 14-032 which entails breaching the western

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-26 most portion of the north foundation wall of the Unit 2 Steam Tunnel. The breach will be 15-feet wide and extend from the top of the foundation wall after demolition (588 AMSL) to an elevation of 580 feet AMSL (i.e., one foot above the exterior water table). To accommodate any future perforation plans, and ensure conservatism, the mixing volume for the DUST-MS modeling is based on a Basement water elevation equal to the 579 foot elevation of surrounding groundwater. The resulting mixing volumes for each Basement are provided in Table 6-9.

Table 6-9 Basement Mixing Volumes for DUST-MS Modeling Basement/Structure Volume (m3)

Unit 1 Containment Building 6.54E+03 Unit 2 Containment Building 6.54E+03 Auxiliary Building 2.84E+04 Turbine Building 2.61E+04 Crib House and Forebay 3.05E+04 WWTF 1.44E+02 Spent Fuel Pool and Transfer Canal 2.08E+02 Main Steam Tunnels (Unit 1 and Unit 2)

NA - Volume included with Turbine Building volume of 2.61E+04 m3 Circulating Water Intake Piping NA - Source term included with Crib House/Forebay and Turbine in DCGL calculation Circulating Water Discharge Tunnels NA - Source term included with Turbine Building in DCGL calculation 6.6.1.3.

Radionuclide Release Rate The release rate is a function of the source term geometry. In all of the Basements with the exception of the Auxiliary Basement and possibly the SFP/Transfer Canal, the contamination is expected to be surficial. This surface contamination may be relatively loosely bound. In these Basements, the release is conservatively assumed to occur instantly such that the entire inventory is available immediately after license termination. Activated concrete will remain in the Under-Vessel area of Containment. The assumption of instant release for Containment is very conservative for activated concrete which would actually release radionuclides very slowly.

The contamination in the Auxiliary Basement, and possibly the SFP/Transfer Canal, has diffused into the concrete resulting in volumetric contamination. The Auxiliary Building has been characterized and shown to be contaminated to a depth of at least the first inch of the concrete and deeper in several locations. Leak detection tests have indicated that the steel liner of the SFP does leak, but the extent of the concrete contamination under the liner is not known at this time.

After the liner has been removed, the underlying concrete of the SFP/Transfer Canal will be characterized. Due to the volumetric source term, the release of contamination from Auxiliary

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-27 and SFP/Transfer Canal concrete, and the resulting maximum water concentrations, will be a driven by time-dependent diffusion controlled release. For these two Basements, a diffusion controlled release model is used. If contamination in the SFP/Transfer Canal is found to be surficial, then the DUST-MS model will be rerun using an instant release rate. Table 6-10 summarizes the release rate assumptions used in DUST-MS modeling for each Basement.

Table 6-10 Summary of DUST-MS Source Term Release Rate Assumptions for the Zion Basements Basement Release Rate Assumption Unit 1 Containment Instant Release (1) (loose surface contamination on steel liner)

Unit 2 Containment Instant Release (1) (loose surface contamination on steel liner)

Auxiliary Diffusion Controlled Release (concrete contamination at depth in concrete)

Turbine Instant Release (limited contamination present at concrete surface with very limited contamination at depth)

Crib House and Forebay Instant Release (limited or no surface contamination)

WWTF Instant Release (limited or no surface contamination)

SFP and Transfer Canals Diffusion Controlled Release (Concrete contamination at depth expected under liner)

(1) A small volume of activated concrete will remain in the Under-Vessel areas of both Containments. The instant release assumption is very conservative for activated concrete.

Diffusion coefficients for each ROC are required to estimate the rate of release from concrete in addition to the parameters listed in Tables 6-4 and 6-5. The diffusion coefficients from concrete will depend on the water to cement ratio used in forming the concrete and the aggregate.

Table 6-11 lists a typical range of diffusion coefficients for concrete and provides reference(s) for the values. The water concentrations are proportional to the diffusion coefficient, so the maximum value in the range was selected for use in the DUST-MS modeling.

The diffusion rate also depends on the contamination depth profile. The majority of the contamination in Auxiliary Basement is found in the first one inch of concrete. However, there are some locations where the contamination is deeper. The diffusion modeling in DUST-MS conservatively assumes that the contamination is 0.5 inch deep. All activity in the concrete, including any activity deeper than 0.5 inch, will be determined during the FSS (see LTP Chapter 5, section 5.5). All activity deeper than 0.5 inch will be assumed to be included in the first 0.5 inch. This is a conservative approach because the deeper contamination would diffuse out more slowly. In addition, assuming that the total inventory is within the first 0.5 inch of concrete will increase the effective concentration in the first 0.5 inch. This assumption will increase the diffusion rate which is driven by the concentration gradient.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-28 Table 6-11 Range of Diffusion Coefficients for Cement and Selected Values for Radionuclides of Concern (Reference 6-21)

Nuclide Diffusion Coefficient Range (cm2/s)

Selected Diffusion Coefficient (cm2/s)

H-3 6.0E 5.5E-07 5.5E-07 Co-60 5.0E 4.1E-11 4.1E-11 Ni-63 8.7E 1.1E-09 1.1E-09 Sr-90 1.0E 5.2E-10 5.2E-10 Cs-134; Cs-137 4.0E 3.0E-09 3.0E-09 Eu-152; Eu-154 1.0E 5.0E-11 5.0E-11 The depth of contamination for DUST-MS diffusion modeling of the concrete in the SFP/Transfer Canal is also assumed to be 0.5 inch. The depth of contamination in the SFP/Transfer Canal concrete is not known at this time and will be characterized after the liner is removed. If contamination is found at depths significantly greater than 0.5 inch, then the model may be re-run using the actual depth profile. This re-run would be at the discretion of ZSRP if it were determined that the 0.5 inch thickness assumption was too conservative. In this case, the results would be made available for NRC review. Any increase in the DCGL as a result of this re-run would require NRC approval. All other DUST-MS parameters would remain the same.

6.6.2.

Sensitivity Analysis Although conservative parameters were selected for DUST-MS as described above, a sensitivity analysis was performed for Kd, porosity, and density to ensure that further parameter review was not necessary. A simple assessment was performed by varying each parameter independently through range of +/- 25% of the selected parameter as shown in Table 6-12.

Table 6-12 Range of DUST-MS Parameters Varied in Sensitivity Analysis Parameter Selected Value Sensitivity Range Kd Table 6-5 (Nuclide Dependent)

+/- 25% of Value in Table 6-5 Porosity 0.25 0.19 - 0.31 Bulk Density 1.5 g/cm3 1.1 - 1.8 g/cm3 The results show minimal impact in varying the parameters through the range as listed below.

No adjustment of the conservatively selected parameter values is deemed necessary.

Kd: An increase in Kd caused a decrease in solution concentration and a slight increase in sorbed concentration on fill. Solution concentration is approximately inversely proportional to Kd. The 25% change in Kd had a minimal impact on the amount sorbed or the backfill concentration (pCi/g). Sr-90 showed the largest percentage change in sorbed concentration of all the nuclides but it was less than 2.5%.

Porosity: Changing porosity had a minor impact on the amount sorbed and solution concentration. The amount of radioactivity in solution was proportional to the porosity (but

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-29 the concentration was lower). This reflects the increased volume of water available for mixing in higher porosity media and corresponding higher total amount of activity in the water.

Density: The solution concentration, sorbed concentration and amount in solution are inversely proportional to density. Increasing density causes a decrease in solution concentration. The change in density has a minor impact (< 2%) on the total amount of radioactivity that is sorbed.

The sensitivity of the depth of contamination in the diffusion release model was also assessed.

As expected, the maximum water concentrations decreased with an increased depth of contamination. Therefore, a minimum concrete contamination depth of 0.5 inches was used in the DUST-MS modeling.

6.6.2.1.

Sensitivity of Well Placement The placement of the well inside the Basement(s) is unlikely because it is assumed that the driller will recognize that the spoils are not natural materials and, that the high pH of the water inside the Basement(s) due to the presence of concrete and cinderblock demolition debris will make the water unsuitable for domestic use. In addition, encountering construction debris during drilling and meeting refusal at the Basement floor will further discourage the use of a well drilled into the Basements. However, the BFM conservatively assumes that the well is placed inside of the Basement(s). A simple assessment was performed in TSD 14-009 to determine the potential effect of well placement outside of the walls of the Basement(s) to illustrate that the well placement assumption was conservative.

For the well placement sensitivity assessment, the well was assumed to be located in the shallow sand aquifer at the closest location downstream of the Basement(s) to the east of the Turbine Building. In this assessment, the Auxiliary Building is modeled with contamination released in this building flowing through the Turbine Building similar to the physical layout at the site. The initial inventory in the Turbine Building was reduced by a factor of 0.001 consistent with the much higher measured concentrations in the concrete of the Auxiliary Building. Water flow through the system is assumed to be at the local groundwater velocity (e.g., the Basement walls are assumed to be transparent and allow free flow of groundwater). The results indicate that the water concentration (and corresponding Resident Farmer dose) would be reduced by approximately two orders of magnitude for Cs-137 if the well were located outside of the Basements at the nearest downstream location. The reduction for Co-60 is much greater. The Sr-90 concentrations are only slightly reduced due to the very low assumed Kd of 2.3 cm3/g.

This analysis further supports the conclusion that the BFM conceptual model, which assumes that the well is placed inside a Basement, is bounding.

6.6.2.2.

DUST-MS Model Results Tables 6-13 and 6-14 (Reference 6-18) provide the results of the DUST-MS calculations for each Basement and ROC. The tables report the maximum Groundwater Concentration Factors (pCi/L per mCi) and corresponding Fill Concentration Factors (pCi/g per mCi). Note that both of these values occur at the same point in time.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-30 The maximum concentrations occur at the time of license termination for the Basements with instant source term release. The time of maximum concentrations varies for each ROC in the Auxiliary Building Basement and SFP/Transfer Canal as a function of half-life and diffusion coefficient. For application in the BFM, the maximum concentration factors are used and conservatively assumed to occur at one point in time for all radionuclides.

Table 6-13 Peak Groundwater Concentration Factors (pCi/L per mCi Total Inventory)

Nuclide Auxiliary (pCi/L/mCi)

Containment (pCi/L/mCi)

Turbine (pCi/L/mCi)

Fuel (pCi/L/mCi)

Crib House

/Forebay (pCi/L/mCi)

WWTF (pCi/L/mCi)

Co-60 4.00E-03 4.57E-01 1.14E-01 5.45E-01 9.77E-02 2.08E+01 Cs-134 1.06E-01 2.26E+00 5.65E-01 1.45E+01 4.83E-01 1.03E+02 Cs-137 3.80E-01 2.26E+00 5.65E-01 5.22E+01 4.83E-01 1.03E+02 Eu-152 1.65E-02 1.07E+00 2.68E-01 2.24E+00 2.29E-01 4.83E+01 Eu-154 1.29E-02 1.07E+00 2.68E-01 1.76E+00 2.29E-01 4.83E+01 H-3 1.40E+02 6.13E+02 1.53E+02 1.91E+04 1.31E+02 2.78E+04 Ni-63 2.92E-01 1.64E+00 4.10E-01 4.01E+01 3.52E-01 7.47E+01 Sr-90 3.01E+00 4.13E+01 1.04E+01 4.12E+02 8.85E+00 1.89E+03 Table 6-14 Peak Fill Material Concentration Factors (pCi/g per mCi Total Inventory)

Nuclide Auxiliary (pCi/g/mCi)

Containment (pCi/g/mCi)

Turbine (pCi/g/mCi)

Fuel (pCi/g/mCi)

Crib House

/Forebay (pCi/g/mCi)

WWTF (pCi/g/mCi)

Co-60 8.92E-04 1.02E-01 2.55E-02 1.22E-01 2.18E-02 4.64E+00 Cs-134 4.77E-03 1.01E-01 2.54E-02 6.53E-01 2.18E-02 4.63E+00 Cs-137 1.71E-02 1.01E-01 2.54E-02 2.35E+00 2.18E-02 4.63E+00 Eu-152 1.58E-03 1.02E-01 2.55E-02 2.15E-01 2.18E-02 4.64E+00 Eu-154 1.22E-03 1.02E-01 2.55E-02 1.67E-01 2.18E-02 4.64E+00 H-3 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 0.00E+00 Ni-63 1.81E-02 1.02E-01 2.54E-02 2.49E+00 2.18E-02 4.64E+00 Sr-90 6.94E-03 9.50E-02 2.38E-02 9.46E-01 2.03E-02 4.33E+00 The Groundwater Concentration Factors are used in conjunction with Groundwater Exposure Factors generated by RESRAD to develop the BFM GW Dose Factors which are one of the inputs to the DCGL calculations in section 6.6.8.

6.6.3.

RESRAD Model The RESRADv7.0 computer code was used to calculate the Resident Farmer dose from a unit radionuclide concentration in the well water. A Groundwater Exposure Factor, in units of mrem/y per pCi/L was generated for each ROC. The Groundwater Exposure Factors are combined with the Groundwater Concentration Factors generated using DUST-MS to calculate the BFM GW Dose Factors for each ROC in units of mrem/y per mCi..

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-31 6.6.3.1.

Parameter Selection RESRAD parameters are classified as behavioral, metabolic or physical. Some parameters may belong to more than one category. The parameter classification is documented in NUREG/CR-6697. Physical parameters are determined by the source, its location, and geological characteristics of the site (i.e., these parameters are source-and site-specific) including the geohydrologic, geochemical, and meteorologic characteristics of the site. The characteristics of atmospheric and biospheric transport up to, but not including, uptake by, or exposure of, the dose receptor would also be considered physical input parameters.

Behavioral parameters define the receptors behavior considering the conceptual model selected for the site. For the same group of receptors, a parameter value could change if the scenario changed (e.g., parameters for recreational use could be different from those for residential use).

For the ZNPS, the behavioral parameters are based on a Resident Farmer scenario and are the same for both the BFM and soil dose assessments.

Metabolic parameters define certain physiological characteristics of the potential receptor. One set of metabolic parameters applies to both the BFM and soil dose assessments. Physical, behavioral and metabolic parameters are treated as deterministic parameters in the final dose modeling to calculate Groundwater Exposure Factors. The deterministic module of the code uses single values for input parameters and generates a single value for dose. The parameter selection process is described below.

Argonne National Laboratory (ANL) ranked physical parameters by priority as 1, 2, or 3.

Priority 1 parameters have the highest potential impact on dose and Priority 3 the least. This ranking is documented in Attachment B to NUREG/CR-6697.

Priority 3 physical parameters were assigned the median values from the parameter distributions defined in NUREG/CR-6697. Priority 1 and 2 parameters were evaluated by uncertainty analysis using the NUREG/CR-6697 parameter distributions. The Partial Rank Correlation Coefficient (PRCC) was used to evaluate the relative sensitivity of the Priority 1 and 2 parameters. A PRCC value less than -0.25 was considered sensitive and negatively correlated to dose. The 25th percentile of the NUREG/CR-6697 distribution was assigned to negatively correlated parameters. A PRCC value greater than 0.25 was considered sensitive and positively correlated to dose. The 75th percentile of the distribution from NUREG/CR-6697 was assigned to positively correlated parameters. Priority 1 and 2 parameters with a lPRCCl less than 0.25 were assigned the median value of the NUREG/CR-6697 parameters.

Consistent with the guidance in NUREG-1757, section I.6.4.2, metabolic and behavioral parameters were assigned the mean values from NUREG/CR-5512 Vol. 3, Residual Radioactive Contamination From Decommissioning Parameter Analysis Table 6.87 (Reference 6-25).

Figure 6-10 provides a flow chart of the parameter selection process.

The RESRAD code contains several Dose Conversion Factor (DCF) libraries that can be selected by the user. The DCF library selected for the BFM applies inhalation and ingestion DCFs from the Environmental Protection Agency (EPA) Federal Guidance Report (FGR) No. 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion and Ingestion (Reference 6-26) and direct external exposure dose

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-32 conversion factors from FGR No. 12 External Exposure to Radionuclides in Air, Water and Soil (Reference 6-27).

There are four RESRAD parameters that were assigned values that are specific to the BFM as listed below:

Time since material placement = 1 year

Mass Balance Groundwater Model

100% of the initial contamination in the water table

No unsaturated zone (unsaturated zone depth = 0)

The parameter value for time since material placement of one year was selected for user convenience to allow RESRAD to calculate an equilibrium well water concentration at run time equal to zero for all radionuclides. The assumption that 100% of the initial contamination is in the water table, no unsaturated zone and Mass Balance Groundwater Model removes the time dependence of travel through an unsaturated zone in the reported well water concentrations as a function of time. All radionuclides achieve maximum well water concentrations at t=0.

However, none of these parameters effect the calculation of the Groundwater Exposure Factors (mrem/y per pCi/L), which can be calculated for any year and any well water concentration since they are unitized. The relationship between dose and well water concentration is independent of time or water concentration.

In a similar manner, the saturated zone and contaminated zone hydrogeological parameters have no impact on the calculation of the unitized Groundwater Exposure Factors for the BFM.

However, instead of using the default values for these parameters they were selected and justified using the full process shown in Figure 6-10. This was done for two reasons, to allow the same parameter set to be used for the site specific soil DCGL determination in section 6.9 (with slight modification) and to eliminate any potential concerns that the hydrogeological parameters could impact the dose calculations due to unforeseen effects on the RESRAD calculations.

Finally, the RESRAD model was run deterministically, i.e., single values were selected for all parameters. In practice, this only affects the few Priority 1 and 2 physical parameters that are not site-specific or sensitive, which would be run with the distributions from NUREG/CR-6697 in a probabilistic approach as opposed to the mean values.

6.6.4.

Uncertainty Analysis Uncertainty analysis was performed to ensure that conservative values are selected for parameters that have a relatively high correlation to dose. Attachment 1 provides the input parameter set used to perform the uncertainty analysis. The parameter selection process is discussed below.

For the uncertainty analysis, deterministic parameters are selected for behavioral, metabolic and Priority 3 physical parameters in accordance with the process in Figure 6-10. The majority of the Priority 1 and 2 physical parameters are assigned the parameter distributions from NUREG/CR-6697. Three site-specific Priority 1 and 2 physical parameters were assigned deterministic values in the uncertainty analysis including cover depth, precipitation, well

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-33 pumping rate (which does not have a recommended distribution in NUREG/CR-6697). In addition, as discussed in section 6.6.1.1, the Kd values were assigned conservative deterministic values based on the review of various literature sources and site-specific data documented in TSD 14-004. The assigned Kd values apply to the basement fill material and are therefore the same as selected for the DUST-MS model (see Table 6-5). There are other site-specific deterministic parameters available, but these are included in the uncertainty analysis by applying the parameter distributions from NUREG/CR-6697 to ensure the appropriate level of justification is provided if one or more of these parameters were determined to be sensitive.

The uncertainty analysis was conservatively run for all ROC individually to maximize the parameter sensitivity. A more realistic approach would be to only apply the radionuclide mixture fractions found at ZNPS. Using the ZNPS fractions could reduce the sensitivity of total dose to some parameters for the low abundance radionuclides. In addition, parameter input rank correlations were not applied in order to maximize variability and corresponding parameter sensitivity. The RESRAD Uncertainty Reports are provided in TSD 14-010. Table 6-15 provides the parameters with lPRCCl values greater than 0.25 and the reported PRCC values.

The PRCC values listed are the highest individual values from the three runs made in the RESRAD Uncertainty Analysis. Table 6-16 and Table 6-17 list the selected 75th or 25th percentile deterministic values from the NUREG/CR-6697 distributions for the sensitive parameters (i.e., those listed in Table 6-15).

The values in Tables 6-16 and 6-17 were used in the RESRAD modeling to determine the Groundwater Exposure Factors. The median of the distributions from NUREG/CR-6697 were assigned to Priority 1 and 2 parameters that were not sensitive (i.e., not listed in Table 6-15).

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-34 Table 6-15 BFM Uncertainty Analysis Results for Parameters with lPRCCl > 0.25 Parameter PRCC Value Co-60 Cs-134 Cs-137 Eu-152 Eu-154 Ni-63 Sr-90 H-3 Depth of Roots 0.33 NS1 NS NS NS NS NS NS Weathering Removal Constant of All Vegetation

-0.61

-0.88

-0.87

-0.89

-0.78

-0.80 NS Wet Weight Crop Yield of Fruit Grain and Non-Leafy Vegetables NS NS NS

-0.51

-0.54 NS NS NS Wet Foliar Interception Fraction of Leafy Vegetables NS NS NS 0.56 0.59 NS NS NS Plant Transfer Factor NS NS NS NS NS NS 0.31 NS Meat Transfer Factor 0.90 0.86 0.85 0.75 0.77 0.32 0.59 NA Milk Transfer Factor 0.56 0.91 0.90 NS NS 0.97 0.68 NA Saturated Zone Hydraulic Conductivity NS NS NS NS NS NS

-0.36

-0.54 Saturated Zone Hydraulic Gradient NS NS NS NS NS NS

-0.59

-0.77 Contaminated Zone Total Porosity NS NS NS NS NS NS

-0.41

-0.77 Density of Contaminated Zone NS NS NS NS NS NS 0.41 0.73 Note 1: NS indicates that the parameter is not sensitive

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-35 Table 6-16 BFM Deterministic Values for Sensitive Parameters from Table 6-12 that are Radionuclide Independent Parameter Percentile Parameter Value Depth of Roots 75th 3.1m Weathering Removal Constant of All Vegetation 25th 21.5 Wet Weight Crop Yield of Fruit Grain and Non-Leafy Vegetables 25th 1.26 kg/m2 Wet Foliar Interception Fraction of Leafy Vegetables 75th 0.70 Saturated Zone Hydraulic Conductivity 25th 1695 Saturated Zone Hydraulic Gradient 25th 0.0018 Contaminated Zone Total Porosity 25th 0.37 Density of Contaminated Zone 75th 1.681 g/cm3 Note 1: Site specific density value of 1.8 used in the RESRAD run.

Table 6-17 BFM Deterministic Values for Sensitive Parameters from Table 6-12 that are Radionuclide Dependent Radionuclide Plant Transfer Factor 75th Percentile Meat Transfer Factor 75th Percentile Milk Transfer Factor 75th Percentile Co-60 NS1 0.058 0.0032 Cs-134 NS 0.065 0.014 Cs-137 NS 0.065 0.014 Eu-152 NS 0.004 NS Eu-154 NS 0.004 NS Ni-63 NS 0.0092 0.032 Sr-90 0.59 0.013 0.0028 H-3 NS NS NS Note 1: NS indicates that the parameter is not sensitive The density of the contaminated zone was identified as sensitive and positively correlated. As noted in Table 6-16, the 75th Percentile of the NUREG/CR-6697 Attachment C distribution is 1.68 g/cm3. However, the site-specific density value for sand is 1.8 g/cm3 (TSD 14-006).

Because the fill will be a combination of concrete and sand, and concrete density is 2.4 g/cm3, the 1.8 g/cm3 for sand is the minimum site-specific value and was therefore applied.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-36 6.6.5.

BFM RESRAD Parameter Set and Groundwater Exposure Factor Calculation The final RESRAD parameter set used to calculate the Groundwater (GW) Exposure Factors is provided in Attachment 2. The RESRAD BFM Summary Report and Concentration Report are provided in TSD 14-010.

A few of the parameters required simple calculations, which are described in the Attachment 2 parameter table. A calculation was also performed to develop a nominal value of 2250 m3 for the well pumping rate parameter including drinking water, livestock consumption and irrigation in the Resident Farmer Scenario. This calculation is provided at the end of Attachment 2.

The GW Exposure Factors are calculated by dividing the maximum dose, which occurs at t=0 in the RESRAD simulations for all ROC, by the well water concentration at t=0 as shown in Equation 6-2. The RESRAD results for each ROC and the calculated GW Exposure Factors are provided in Table 6-18.

Equation 6-2

! " / $$$

where:

GW Exposure Factor (i) = Dose from unitized groundwater concentration (mrem/y per pCi/L)

Total Dose (i) = Total dose from radionuclide (i) calculated by RESRAD (mrem/yr)

GW Concentration (i) = Groundwater concentration for radionuclide (i) calculated by RESRAD (pCi/L)

Table 6-18 RESRAD Results and GW Exposure Factors for BFM model Radionuclide Dose (mrem/y)

Groundwater Concentration (pCi/L)

GW Exposure Factor (mrem/y per pCi/L)

Drinking Water Plant/Meat/

Milk Total Co-60 5.40E-02 5.82E-02 1.12E-01 4.48E+00 2.50E-02 Cs-134 6.58E-01 1.28E+00 1.94E+00 2.21E+01 8.75E-02 Cs-137 5.23E-01 1.01E+00 1.54E+00 2.21E+01 6.94E-02 Eu-152 3.17E-02 6.30E-03 3.80E-02 1.05E+01 3.62E-03 Eu-154 4.61E-02 9.14E-03 5.52E-02 1.05E+01 5.26E-03 H-3 1.38E-01 7.88E-02 2.17E-01 4.89E+03 4.43E-05 Ni-63 4.42E-03 1.13E-02 1.57E-02 1.61E+01 9.78E-04 Sr-90 2.87E+01 1.49E+01 4.36E+01 3.99E+02 1.09E-01

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-37 6.6.6.

BFM Groundwater Dose Factors BFM GW Dose Factors are dose conversion factors in units of mrem/yr per mCi total inventory.

The Resident Farmer dose includes the exposure pathways listed in section 6.5.4. The BFM GW Dose Factor accounts for all of the exposure pathways, except the drilling spoils pathway which is addressed in section 6.6.7. The BFM GW Dose Factor is calculated using Equation 6-3. BFM GW Dose Factors were calculated for each Basement and each ROC in TSD 14-010 and are provided in Table 6-19.

Equation 6-3

%& " , (

$$$ , (

where:

BFM GW Dose Factor (i,b) = BFM GW Dose Factor for radionuclide (i) and Basement (b) (mrem/y per mCi)

GW Concentration Factor (i,b) = Groundwater Concentration Factor for Radionuclide (i) and Basement (b) (pCi/L per mCi)

GW Exposure Factor (i,b) = Groundwater Exposure Factor for Radionuclide (i) and Basement (b) (mrem/yr per pCi/L)

Table 6-19 BFM GW Dose Factors (mrem/yr per mCi Total Inventory)

Nuclide Auxiliary (mrem/yr per mCi)

Containment (mrem/yr per mCi)

Fuel(1)

(mrem/yr per mCi)

Turbine (mrem/yr per mCi)

Crib House

/Forebay (mrem/yr per mCi)

WWTF (mrem/yr per mCi)

Co-60 1.00E-04 1.14E-02 NA 2.87E-03 2.85E-03 5.21E-01 Cs-134 9.27E-03 1.98E-01 NA 4.94E-02 4.91E-02 9.03E+00 Cs-137 2.64E-02 1.57E-01 NA 3.92E-02 3.90E-02 7.17E+00 Eu-152 5.96E-05 3.87E-03 NA 9.69E-04 9.64E-04 1.75E-01 Eu-154 6.77E-05 5.62E-03 NA 1.41E-03 1.40E-03 2.56E-01 H-3 6.21E-03 2.72E-02 NA 6.80E-03 6.75E-03 1.23E+00 Ni-63 2.86E-04 1.61E-03 NA 4.01E-04 4.00E-04 7.31E-02 Sr-90 3.29E-01 4.51E+00 NA 1.13E+00 1.12E+00 2.06E+02 (1) As discussed in section 6.5.4, the BFM GW Dose Factors are not applicable to the SFP/Transfer Canal.

Table 6-19 includes an adjustment to the Table 6-18 peak groundwater concentration factors for the Crib House/Forebay. A revision to the demolition plan for the Crib House/Forebay was made that entailed leaving interior walls as opposed to removing them. This resulted in a decrease in the basement mixing volume as compared to that assumed in the DUST-MS modeling provided in TSD-14-009 and a corresponding increase in the fill and groundwater

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-38 concentrations calculated in TSD 14-009. The BFM GW DFs are directly proportional to the groundwater concentrations which are inversely proportional to the ratio of revised/original mixing volumes. The ratio of the revised/original mixing volumes for the Crib House/Forebay was calculated in TSD 14-014, Revision 1 and determined to be 0.86. The Crib House/Forebay BFM GW Dose Factors were therefore adjusted higher by the inverse of 0.86 or a factor of 1.16.

Note that the Crib House/Forebay surface area was also adjusted to account for the additional remaining walls but the change in surface area does not affect the calculation of the BFM Dose Factors because the unit inventory approach used was independent of surface area.

6.6.7.

BFM Drilling Spoils Dose Factors The BFM Drilling Spoils scenario addresses one of the BFM exposure pathways listed in section 6.5.4 by calculating the dose from residual radioactivity in fill material (resulting from release from surfaces to clean fill after backfill) which is brought to the surface during the installation of a well in the basement. The activity remaining in the concrete surfaces, if any, is also included in the drilling spoils source term. The drilling spoils exposure pathway was included after initial screening in ZionSolutions TSD 14-021 Basement Fill Model (BFM)

Drilling Spoils and Alternate Exposure Scenarios (Reference 6-28) indicated that the pathway could potentially contribute greater than 10% of the total BFM dose. TSD 14-021 also provides the BFM Drilling Spoils Dose Factor calculations. BFM Drilling Spoils Dose Factors are calculated in units of mrem/yr per mCi total inventory.

The source term for the BFM Drilling Spoils scenario is the average concentration in fill, and remaining in concrete, at the time of maximum groundwater concentration which is the time used to assess exposure for all other BFM pathways. As discussed previously, the fill is clean at the time of license termination but is assumed to adsorb activity after release from the concrete surfaces (or steel liner for Containment).

For Basements with instant release assumptions, the maximum groundwater concentrations occur at t=0 for all radionuclides. The remaining fraction in concrete is assumed to be zero since all activity is released to the water. For Basements with diffusion controlled release (the Auxiliary Basement and the SFP/Transfer Canal), the time of maximum groundwater (and fill) concentrations is a function of half-life and diffusion coefficient, and therefore radionuclide-specific. The corresponding fractions of inventory remaining in concrete at the time of maximum groundwater concentration are also radionuclide-specific. To ensure conservatism and consistency in the BFM source term, the maximum fill concentrations (which occur at the time of maximum groundwater concentrations) are applied for each radionuclide regardless of when the maximum occurs.

There are a number of ways that installers handle and dispose of drilling spoils, including the use of slurry pits, tanks, and dumping the drilling spoils on the existing surface soils. The use of pits would likely involve additional dilution by refilling the pit with the material excavated during its construction. As a conservative assumption, no dilution of the spoil material is assumed after being brought to the surface.

The borehole diameter is assumed to be 8 inches to accommodate the installation of a 4 inch diameter casing. The well is assumed to be drilled into the basement fill down to the concrete floor where refusal is met and drilling stopped. The extent of drilling into concrete is

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-39 conservatively assumed to be sufficient to capture 100 percent of the remaining residual radioactivity in concrete. The volume of spoil material brought to the surface is calculated based on the borehole diameter and depth of drilling which is defined as the distance from the ground surface to the bottom of the Basement. All material, including the concrete, fill, and clean overburden is brought to the surface where it is uniformly mixed and spread over a circular area to a depth of 0.15 m.

The dose from the circular area at the surface is calculated using the surface soil DCGLs and Area Factors (AF) (see section 6.9 for soil DCGL calculations). As described in TSD 14-021, the size of the area over which the drilling spoils are spread ranges from 0.92 m2 to 3.56 m2, depending on the Basement. The BFM Drilling Spoils Dose Factors are calculated in TSD 14-021 for each Basement and each ROC and are provided Table 6-20. Note that the Drilling Spoils Dose Factors for H-3 are all zero because the distribution coefficient is zero and there is no adsorption onto fill or remaining in concrete.

Table 6-20 BFM Drilling Spoils Dose Factors (mrem/yr per mCi Total Inventory)

Nuclide Auxiliary (mrem/yr per mCi)

Containment (mrem/yr per mCi)

Fuel (mrem/yr per mCi)

Turbine (mrem/yr per mCi)

Crib House

/Forebay (mrem/yr per mCi)

WWTF (mrem/yr per mCi)

Co-60 1.07E-02 2.97E-02 1.58E-01 9.58E-03 2.07E-02 2.26E-01 Cs-134 6.29E-03 1.72E-02 9.41E-02 5.54E-03 1.19E-02 1.31E-01 Cs-137 3.22E-03 7.27E-03 4.83E-02 2.35E-03 5.05E-03 5.57E-02 Eu-152 5.02E-03 1.38E-02 7.46E-02 4.45E-03 9.58E-03 1.05E-01 Eu-154 5.57E-03 1.46E-02 8.25E-02 4.73E-03 1.02E-02 1.12E-01 H-3 0.00E+00 0.00E+00 1.45E-09 0.00E+00 0.00E+00 0.00E+00 Ni-63 3.23E-08 5.61E-08 3.78E-07 1.86E-08 4.81E-08 4.16E-07 Sr-90 6.26E-05 1.39E-04 7.60E-04 4.61E-05 1.16E-04 1.049E-04 Table 6-20 includes an adjustment to the Table 6-18 peak groundwater concentration factors for the Crib House/Forebay which are directly proportional to the peak fill concentrations used in the Drilling Spoils scenario. A revision to the demolition plan for the Crib House/Forebay was made that entailed leaving interior walls as opposed to removing them. This resulted in a decrease in the basement mixing volume as compared to that assumed in the DUST-MS modeling provided in TSD-14-009 and a corresponding increase in the fill and groundwater concentrations calculated in TSD 14-009. The Drilling Spoils Dose Factors are directly proportional to the fill concentrations which are inversely proportional to the ratio of revised/original mixing volumes.

The ratio of the revised/original mixing volumes for the Crib House/Forebay was calculated in TSD 14-014, Revision 1 and determined to be 0.86. The Crib House/Forebay BFM Drilling Spoils DFs were therefore adjusted higher by the inverse of 0.86 or a factor of 1.16. Note that the Crib House/Forebay surface area was also adjusted to account for the additional remaining

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-40 walls but the change in surface area does not affect the calculation of the BFM Dose Factors because the unit inventory approach used was independent of surface area.

6.6.8.

Basement Surface DCGLs Derived Concentration Guideline Levels, in units of pCi/m2 of basement surface area, were calculated in Reference 6-13, section 2.5 for the BFM Groundwater and BFM Drilling Spoils scenarios individually and are designated as the DCGLBS (Basement Scenario DCGLs). The Groundwater DCGLBS and Drilling Spoils DCGLBS are combined to generate the Basement DCGL (DCGLB) which represent the combined dose from both the groundwater and drilling spoils scenarios. The DCGLB is directly analogous to the DCGLW as defined in MARSSIM and is the DCGL used during FSS to demonstrate compliance.

A DCGL was calculated for each basement surface survey unit. For the purpose of this calculation, a surface includes all concrete walls and floors of the basements or the steel liner on the walls and floors of Containment. The areal extent of the walls and floors is the surface area and includes all contamination, volumetric at depth and on the surface, within the defined area. Note that embedded pipe and penetrations will remain in the basements. Embedded pipe and penetrations within or interfacing each basement structure were designated as separate survey units, with separate DCGL calculations for each, as described in sections 6.13 and 6.14.

After the basement surface areas were adjusted as described in section 6.6.8.1, the DCGLBS values were calculated for each basement using Equation 6-4. Adjustment factors of 0.90 for Containment and 0.95 for all other basements are included in Equation 6-4 to account for the dose from insignificant contributors (see section 6.5.2.3). The DCGLB values were calculated by combining the Groundwater and Drilling Spoils DCGLBS values using Equation 6-5.

Equation 6-4

)*+,-.,/

25 234 56789:;< )3/

1 5?@ABCDEFGB

1H 09 K* )<L7 ?MNOLP78Q Where:

DCGLBS, i

= Groundwater or Drilling Spoils scenario DCGL for radionuclide (i) (pCi/m2)

BFM Scenario DFi

= Basement Fill Model Dose Factor for radionuclide (i) (mrem/yr per mC) 1E+09

= Conversion factor (pCi/mCi) 25

= 25 mrem/yr dose criterion SAb (adjusted)

= Adjusted surface area of basement (b) (m2)

IC Dose Adjustment = Insignificant Contributor Dose Adjustment Factor (0.9 for Containment and 0.95 for all other basements - see section 6.5.2.3)

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-41 Equation 6-5

)*+,-/

1 R

1

+S )*+,-./

1

)5 )*+,-./T Where:

DCGLBi

= Basement Surface DCGL for radionuclide (i) (pCi/m2)

GW DCGLBSi

= Groundwater scenario DCGL for radionuclide (i) (mrem/yr per mCi)

DS DCGLBSi

= Drilling Spoil scenario DCGL for radionuclide (i) (mrem/yr per mCi) 6.6.8.1.

Basement Surface Area Adjustments Basement surface area adjustments were required to ensure that the DCGLs account for the contribution of residual radioactivity from basements/structures that cannot, on their own, support a water supply well but are hydraulically connected to a basement that can support a well. These include the Circulating Water Intake Pipes, Circulating Water Discharge Tunnels (and associated piping), Buttress Pits/Tendon Tunnels, and the SFP/Transfer Canal. The surface area adjustments result in lowering the DCGL concentrations (pCi/m2) in the affected basements and structures, from that which would be calculated for each individually, by requiring the allowable total activity to be uniformly distributed over the larger, combined surface areas.

The first area adjustment is to the Turbine Basement and Crib House/Forebay. As stated in Table 6-9, the activity in the Circulating Water Intake Pipes is included in both the Crib House/Forebay and the Turbine Basement. The activity in the Circulating Water Discharge Tunnels is included with the Turbine Basement. The Intake Pipe has been grouted essentially eliminating the hydraulic connections. The major hydraulic connections between the Discharge Tunnels and the Turbine basement will be isolated as a part of the decommissioning process but two 48 inch diameter service water pipes that run between the Turbine Basement and the Discharge Tunnels will remain open and maintain the hydraulic connection, at least to some extent. For the purpose of the DCGL calculation, the hydraulic connections to the Intake Pipe and Discharge Tunnels are assumed to be fully regained in the future after degradation of the isolation barriers and grout.

The surface DCGL calculations account for the activity in the Intake Pipes and Discharge Tunnels by summing the surface areas of the connected structures and using the summed areas for the DCGL calculation. The Intake Pipe surface area is added to the Crib House/Forebay.

The Intake Pipe is also connected to the Turbine basement and therefore, the Intake Pipe surface area is also added to the Turbine Basement. The activity in the Intake Pipe is conservatively assumed to be in both basements simultaneously. The Discharge Tunnel surface area is added to the Turbine Basement. There is also a group of pipes that are within the Turbine building and connected to the Discharge Tunnels including the remaining portions of the 12 foot diameter downcomer pipes, the 36 inch and 48 inch diameter standpipes, and the 48 inch diameter service water return pipes. There are also large diameter pipes on the east side of the Discharge Tunnel Valve House. The internal surface areas of these Circulating Water Discharge Pipes are also added to the summed area used for the Turbine Basement DCGL calculation.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-42 The summed areas were then used as the SAb (adjusted) term in Equation 6-4 to calculate the DCGLs for the Crib House/Forebay and Turbine Basement. As seen in Equation 6-4, increasing the surface area decreases the DCGLs. The lower DCGLs calculated for the Crib House/Forebay and Turbine Basement, based on the summed areas, were then also applied to the Intake Pipes and Discharge Tunnels, respectively. The lower DCGL for either the Crib House/Forebay or the Turbine Basement will be applied to the Intake Pipe. However, this is a minor distinction given that FSS measurements in the Intake Pipe have all been below detection limits which are orders of magnitude below the DCGLs. The Discharge Tunnel FSS results will be included in the dose assessment for the Turbine Basement. The Intake Pipe FSS results will be included with both the Crib House/Forebay and Turbine Basement dose assessments (see LTP Chapter 5, section 5.5.6. for discussion of basement surface dose assessment)

A second surface area adjustment was required to account for the contribution of residual radioactivity in the SFP/Transfer Canal to the groundwater pathway. As discussed in section 6.5.4, the SFP/Transfer Canal geometry could not support a water well and therefore the BFM Groundwater Dose Factor was set to zero (see Table 6-19). However, the potential for the residual radioactivity in the SFP/Transfer Canal to contribute to the groundwater pathway is accounted for by adding the SFP/Transfer Canal surface area to the Containment Basement and Auxiliary Basement surface areas in the DCGL calculation. The activity could mix with the Containment Basement through the Fuel Transfer Tube. Activity could mix with the Auxiliary Basement through an opening created by removing the wall between the Transfer Canal and Auxiliary Basement during demolition. The surface area adjustment, and corresponding DCGL calculations, conservatively assume that the activity in the SFP/Transfer Canal is in both the Containment and Auxiliary Basement simultaneously.

The Buttress Pits and Tendon Tunnels are hydraulically connected to the Steam Tunnels. The surface areas of these structures are therefore added to the Turbine Basement.

The inputs to the calculation of adjusted surface areas are provided in Tables 6-21 to 6-23. The SFP/Transfer Canal and WWTF do not require adjustment. The surface areas in Table 6-21 were used in the DCGL calculations for the SFP/Transfer Canal and WWTF. The DCGL calculations, using Equations 6-4 and 6-5, are performed and documented in Reference 13, section 2.5.

Table 6-21 Basement Surface Areas (Walls and Floors)

Basement Wall and Floor Surface Area (1) m2 Auxiliary Basement 6503 Containment Basement 2759 Turbine Building Basement 14864 SFP/Transfer Canal 723 Crib House/Forebay 13842 WWTF 1124 (1)

Reference:

TSD 14-014 Revision 1, Table 64

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-43 Table 6-22 Surface Areas for Circulating Water Intake Pipe, Circulating Water Discharge Tunnel, Circulating Water Discharge Pipes and Buttress Pits/Tendon Tunnels Structure Surface Area ft2 Surface Area m2 Circulating Water Discharge Tunnels (1) 52400 4868 Circulating Water Intake Pipes (2) 47491 4412 Circulating Water Discharge Pipes (3) 11570 1075 Buttress Pits/Tendon Tunnels (4) 20626 1916 (1) Reference TSD 14-014, Table 64.

(2) TSD 14-016, Table 46 (3) TSD 14-016, Table 50.

(4) TSD 14-014, Rev 3, Tables 60 & 63 and TSD 13-005 Rev 1 Table 15 Table 6-23 Adjusted Basement Surface Areas for DCGL Calculation Basement Structures Included in Total SA/V Calculation Total SA m2 Containment Containment + SFP/Transfer Canal 3482 Auxiliary Auxiliary + SFP/Transfer Canal 7226 Turbine Turbine + Circulating Water Discharge Tunnel +

Circulating Water Intake Pipe + Circulating Water Discharge Pipes + Buttress Pits/Tendon Tunnels 27135 Crib House/Forebay Crib House/Forebay + Circulating Water Intake Pipe 18254 SFP/Transfer Canal (1)

SFP/Transfer Canal 723 WWTF1 WWTF 1124 (1) No area adjustment required. The basement surface areas in Table 6-21 are used in the DCGL calculation.

The Groundwater and Drilling Spoils DCGLBS values were calculated using Equation 6-4 with inputs from the BFM Dose Factors in Tables 6-19 and 6-20, respectively, and the surface areas in Table 6-23 for the SAb (adjusted) term. The results are provided in Tables 6-24 and 6-25. The DCGLB values were calculated using Equation 6-5 with results provided in Table 6-26.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-44 Table 6-24 Adjusted BFM Groundwater Scenario DCGLBS (Adjusted for IC Dose)

Nuclide Auxiliary (pCi/m2)

Containment (pCi/m2)

SFP/

Transfer Canal

((pCi/m2)

Turbine (pCi/m2)

Crib House/

Forebay (pCi/m2)

WWTF (pCi/m2)

Co-60 3.28E+10 5.65E+08 NA 3.05E+08 4.57E+08 4.05E+07 Cs-134 3.55E+08 3.27E+07 NA 1.77E+07 2.65E+07 2.34E+06 Cs-137 1.25E+08 4.12E+07 NA 2.23E+07 3.34E+07 2.95E+06 Eu-152 5.52E+10 1.67E+09 NA 9.03E+08 1.35E+09 1.21E+08 Eu-154 4.85E+10 1.15E+09 NA 6.22E+08 9.29E+08 8.24E+07 H-3 5.30E+08 2.38E+08 NA 1.29E+08 1.93E+08 1.71E+07 Ni-63 1.15E+10 4.02E+09 NA 2.18E+09 3.25E+09 2.89E+08 Sr-90 9.98E+06 1.43E+06 NA 7.74E+05 1.16E+06 1.03E+05 Table 6-25 Adjusted BFM Drilling Spoils Scenario DCGLBS (Adjusted for IC Dose)

Nuclide Auxiliary (pCi/m2)

Containment (pCi/m2)

SFP/

Transfer Canal (pCi/m2)

Turbine (pCi/m2)

Crib House/

Forebay (pCi/m2)

WWTF (pCi/m2)

Co-60 3.07E+08 2.18E+08 2.08E+08 9.13E+07 6.28E+07 9.34E+07 Cs-134 5.23E+08 3.77E+08 3.49E+08 1.58E+08 1.09E+08 1.61E+08 Cs-137 1.02E+09 8.89E+08 6.80E+08 3.73E+08 2.58E+08 3.80E+08 Eu-152 6.54E+08 4.69E+08 4.41E+08 1.97E+08 1.36E+08 2.01E+08 Eu-154 5.91E+08 4.41E+08 3.98E+08 1.85E+08 1.28E+08 1.89E+08 H-3 2.26E+15 4.45E+15 2.26E+16 6.02E+14 8.95E+14 1.45E+16 Ni-63 1.02E+14 1.15E+14 8.69E+13 4.71E+13 2.70E+13 5.08E+13 Sr-90 5.25E+10 4.63E+10 4.32E+10 1.90E+10 1.12E+10 2.03E+10

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-45 Table 6-26 Adjusted Basement DCGLB (Adjusted for IC Dose)

Nuclide Auxiliary (pCi/m2)

Containment (pCi/m2)

SFP/

Transfer Canal (1)

(pCi/m2)

Turbine (pCi/m2)

Crib House/

Forebay (pCi/m2)

WWTF (pCi/m2)

Co-60 3.04E+08 1.57E+08 1.57E+08 7.03E+07 5.52E+07 2.83E+07 Cs-134 2.11E+08 3.01E+07 3.01E+07 1.59E+07 2.13E+07 2.31E+06 Cs-137 1.11E+08 3.94E+07 3.94E+07 2.11E+07 2.96E+07 2.93E+06 Eu-152 6.47E+08 3.66E+08 3.66E+08 1.62E+08 1.23E+08 7.55E+07 Eu-154 5.83E+08 3.19E+08 3.19E+08 1.43E+08 1.12E+08 5.74E+07 H-3 5.30E+08 2.38E+08 2.38E+08 1.29E+08 1.93E+08 1.71E+07 Ni-63 1.15E+10 4.02E+09 4.02E+09 2.18E+09 3.25E+09 2.89E+08 Sr-90 9.98E+06 1.43E+06 1.43E+06 7.74E+05 1.16E+06 1.03E+05 (1) DCGL for SFP/Transfer Canal set equal to the lower of either the Auxiliary or Containment DCGL Containment DCGL was lower for all ROC therefore SFP/Transfer Canal DCGL set equal to Containment 6.6.9.

Basement Surface Elevated Areas Class 1 survey units that pass the Sign test but have small areas with concentrations exceeding the DCGLB would be tested to demonstrate that these small areas meet the dose criterion using the Elevated Measurement Comparison (EMC). There are currently seven Class 1 areas at Zion, the Auxiliary Basement, the SFP/Transfer Canal, the Unit 1 and Unit 2 Containment basements (including the Under-Vessel area and the exposed steel liner above the 565 foot elevation) and the WWTF (see LTP Chapter 5 Table 5-18 for survey unit designations in all basements).

Area Factors (AF) would be required to perform the EMC test. The AF is defined as the magnitude by which the concentration within the small area of elevated activity can exceed the DCGLB while maintaining compliance with the dose criterion.

The BFM is a mixing model that is independent of the distribution of the residual radioactivity.

The calculation of the DCGLB values support the mixing assumption by assuming uniform contamination over all basement walls and floors. An individual FSS ISOCS measurement that exceeds the DCGLB could conceptually be acceptable if it satisfies an EMC test. For example, assuming full mixing, the AF for an Auxiliary Basement FSS ISOCS measurement could be as high as the total surface area divided by the ISOCS FOV (7226/28 = 258). However, consistent with the bounding approach used to develop the conceptual model, and to support the assumption of uniform mixing, no AF will be assigned to the results of FSS ISOCS measurements. Any FSS ISOCS measurement that exceeds the DCGLB (or an SOF of one considering all ROC) will result in remediation. Note that as discussed in LTP Chapter 5, lower, Operational DCGLs, will be used as investigation levels as opposed to the DCGLB.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-46 6.7.

Alternate Exposure Scenarios for Backfilled Basements Two alternate scenarios were evaluated in TSD 14-021 that involve a change to the as left backfilled geometry in the Resident Farmer scenario. A third alternate scenario was evaluated in TSD 14-010 related to the drilling spoils pathway.

The first alternate scenario entails construction of a house basement within the fill material.

Note that the assumed three meter depth of the basement excavation is insufficient to encounter fill material potentially containing residual radioactivity (resulting from leaching of residual radioactivity from surfaces after backfill) assuming the Basement is not constructed within the saturated zone. However, a simple check of direct radiation dose, assuming a residual radioactivity inventory at the hypothetical maximum levels based on the Basement Dose Factors, was conducted to confirm the expectation that the dose would be negligible. The dose calculation is provided in TSD 14-021 with a result of 0.03 mrem/yr for the Auxiliary Basement and 0.5 mrem/yr for the SFP/Transfer Canal. The remaining Basements do not contain significant inventories and were not assessed.

The second alternate scenario assumes large scale excavation of parts or all of the backfilled structural concrete and fill after the ISFSI is decommissioned (assumed to be 10 years after license termination). A simple calculation was performed to estimate the average concentrations in the excavated concrete and fill assuming a residual radioactivity inventory at the hypothetical maximum levels and the ZNPS radionuclide mixture provided in Table 6-3. The assessment was performed for all basements although only the Auxiliary Basement is expected to contain significant levels of residual radioactivity at license termination. (assuming all concrete is removed from Containment).

If a large-scale excavation of the basements were to occur, it would not be for residential use but to develop the property for industrial use. The cost and technical challenges of the excavation required for the deep basements, that are all below the water table, would only be justified for a large scale industrial project that would be present on the site for decades. Therefore, for the assessment of the large scale industrial excavation scenario an Industrial Use soil DCGL (DCGLI) was developed assuming an industrial use scenario (see Reference 6-13, section 6). A period of 10 years was assumed before excavation begins. The DCGLI was used only for the evaluation of the less likely but plausible alternate excavation scenario and is not proposed for any compliance demonstration.

The average activity in the excavated concrete and fill was compared to the soil DCGLI values provided in Reference 6-13, Table 18, as a simple screening assessment for this low probability scenario. Applying the summation rule, and conservatively performing the calculation for each Basement separately, the excavation dose was calculated. The dose results from TSD 14-021, Revision 1, Tables 22 and 26 are reproduced in Table 6-27. In addition, the dose from excavated fill was also evaluated in TSD 14-010 at the Operational DCGL dose fraction of 0.448 assigned in ZionSolutions TSD 17-004 "Operational Derived Concentration Guideline Levels for Final Status Surveys" (Reference 6-31). The results are provided in the last row of Table 6-27.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-47 Table 6-27 Large Scale Industrial Excavation Alternate Scenario Dose Auxiliary (mrem/yr)

Containment (mrem/yr)

SFP/

Transfer Canal (mrem/yr)

Turbine (mrem/yr)

Crib House/

Forebay (mrem/yr)

WWTF (mrem/yr)

Concrete AF 6.66 2.65 10.72 2.37 7.51 0.64 Concrete No AF 8.57 3.90 20.02 2.83 9.96 1.43 Fill AF 4.24 2.52 16.77 2.71 3.17 0.40 Fill No AF 4.89 2.97 31.40 3.05 3.63 0.74 Fill No AF at Operational DCGL1 2.19 1.33 14.07 1.37 1.63 0.33 (1) Dose values in mrem/yr No AF row multiplied by Operational DCGL dose fraction for basements of 0.448.

The dose from the less likely but plausible industrial excavation scenario was calculated applying the AFs (interpolated) from Table 6-40 to the surface area covered by the excavated material assuming the material is spread over a one meter depth on the ground surface. However, the Table 6-40 AFs were calculated for the Resident Farmer scenario resulting in higher values than would be applicable to for the Industrial Scenario due to elimination of the plant pathway.

Therefore, the dose was also calculated without AFs to provide a maximum value.

NUREG-1757 recommends that greater assurance be provided to demonstrate that a less likely but plausible land use is unlikely if the dose from the scenario is significant. The maximum dose from all basements, for excavated fill and concrete, was 31.40 mrem/yr for the SFP/Transfer Canal fill assuming no AF adjustment and activity at the DCGLB concentrations.

The dose for the SFP/Transfer Canal including an AF adjustment was 16.77 mrem/yr. If AFs were calculated for the Industrial Use scenario it would likely result in a dose less than 25 mrem/yr at the DCGLB concentrations. However, the actual source term for the SFP/Transfer canal will be reduced by a factor of 0.448 in order to comply with Operational DCGLs listed in LTP Chapter 5, Table 5-4. The maximum Large Scale Industrial Excavation Dose from fill at Operational DCGL concentrations is 14.07 mrem/yr (0.448*31.40). The low dose values reported in Table 6-29 for the less likely but plausible large-scale excavation land use are considered not significant.

The third alternate scenario assumes that the drill for a water well encounters penetrations, embedded pipe, and basement surfaces with no activity released to the fill. The activity in the penetration, embedded pipe or basement surface that is captured by the drill is assumed to be brought to the surface in the drilling spoils. The source term was the maximum ROC mixture hypothetically allowable given the DCGLs and radionuclide mixture percentages. Two receptors were evaluated; the resident farmer and a worker. The calculation details are provided in TSD 14-010, Revision 6, section 12. The maximum hypothetical dose for the Resident Farmer are provided in Tables 6-28 to 6-30. The maximum hypothetical worker dose from all sources (penetrations, embedded pipe, basement surfaces) was 4.59 mrem/yr. The drilling spoils worker dose was also calculated for each ROC individually, for all penetrations, embedded pipe, and

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-48 basement surfaces, assuming residual radioactivity at the DCGL concentrations. The maximum worker dose from any individual ROC assuming DCGL concentrations was 7.61 mrem/yr.

Table 6-28 The maximum hypothetical resident farmer doses from penetrations for the Alternate Drilling Spoils Scenario (assuming well drilled 30 years after license termination)

Auxiliary (mrem/yr)

Containment (mrem/yr)

Fuel (mrem/yr)

Turbine (mrem/yr)

Crib House/

Forebay (1)

(mrem/yr)

WWTF (1)

(mrem/yr) 6.97 6.96 23.54 6.15 NA NA (1) No penetrations in Crib House/Forebay or WWTF Table 6-29 The maximum hypothetical resident farmer doses from embedded pipe for the Alternate Drilling Spoils Scenario (assuming well drilled 30 years after license termination)

Auxiliary Floor Drain (mrem/yr)

Containment IC Sump Drain (mrem/yr)

Steam Tunnel Floor Drain (mrem/yr)

Tendon Tunnel Floor Drain (mrem/yr)

Turbine Floor Drain (mrem/yr) 13.1 3.39 71.16 16.51 20.16 Table 6-30 The maximum hypothetical resident farmer dose from basement surfaces for the Alternate Drilling Spoils Scenario (assuming well drilled 30 years after license termination)

Auxiliary (mrem/yr)

Containment (mrem/yr)

Fuel (mrem/yr)

Turbine (mrem/yr)

Crib House/

Forebay (mrem/yr)

WWTF (mrem/yr) 0.34 0.12 0.16 0.06 0.08 0.01 The alternate drilling spoils scenario resident farmer dose for the Steam Tunnel Floor Drains is calculated to be 71.16 mrem/yr using the hypothetical maximum activity that could be allowed to remain. However, the actual levels of activity in these drains is expected to be orders of magnitude lower than the hypothetical maximum. The alternate drilling spoils scenario dose for all other embedded pipe, penetrations and basement surfaces are below 25 mrem/yr. The DCGLs for the Steam Tunnel Floor Drains will be reduced by a factor of 2.89 (71.16/25) which will reduce the maximum dose to 25 mrem/yr. The commitment to reduce the Steam Tunnel Floor Drain DCGLs is provided in LTP Chapter 5, section 5.5.5.

6.8.

Soil Dose Assessment and DCGL Site-specific DCGLs were developed for residual radioactivity in surface and subsurface soil that represent the 10 CFR 20.1402 dose criterion of 25 mrem/yr. A DCGL was calculated for each ROC.

Surface soil is defined as contamination contained in the first 0.15 m layer of soil. Subsurface soil is defined as a layer of soil beginning at the surface that extends beyond 0.15 m. The

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-49 subsurface soil thickness is arbitrarily set to a 1 m depth. DCGLs are calculated for both the 0.15 m and 1 m thicknesses. Both the surface and subsurface DCGLs assume a continuous source term layer from the ground surface downward. There are no expectations of encountering soil contamination in a geometry consisting of a clean surface layer of soil over a contaminated subsurface soil layer.

6.8.1.

Soil Source Term During the initial characterization of impacted soils at ZNPS, 888 surface soil samples and 723 subsurface soil samples were taken and analyzed for plant-derived radionuclides. Cs-137 was detected at concentrations greater than MDC in 212 samples and Co-60 was detected at concentrations greater than MDC in 42 samples. The majority of the positive Cs-137 samples were in the range of background concentrations and unlikely to be plant-derived activity. The highest concentration of Cs-137 detected was 3.4 pCi/g in surface soils in a Class 1 open land survey unit located next to Unit 1 Containment. The highest level of Cs-137 detected in a surface soil sample taken from a Class 2 or Class 3 open land survey unit was 1.1 pCi/g. The highest concentration of Co-60 detected in any surface soil sample taken was 0.7 pCi/g.

For subsurface soil samples, Cs-137 was detected at concentrations greater than MDC in 15 samples and Co-60 was detected at concentrations greater than MDC in one sample. The highest level of Cs-137 detected in a subsurface soil sample was 1.0 pCi/g and the one sample where Co-60 was positively detected had a concentration of 0.1 pCi/g. In addition, nine surface soil samples and one subsurface soil samples where gamma spectroscopy indicated the presence of Co-60 and/or Cs-137 were analyzed for all ROC, including HTD radionuclides. No other plant-derived radionuclides were positively identified by the HTD analyses.

The results of surface and subsurface soil characterization in the impacted area of ZNPS indicate that there is minimal residual radioactivity in soil above background. However, the assessment of potential subsurface soil contamination is not complete at the time of this LTP submittal (Revision 0). Soil sampling in difficult to access areas such as under building foundations and surrounding buried structures has been deferred until access is more readily available. Based on the characterization survey results to date, ZSRP does not anticipate the presence of significant soil contamination in the areas remaining to be characterized.

6.8.2.

Soil Radionuclides of Concern, Insignificant Contributor Dose and Surrogate Ratio The radionuclides of concern for soil were determined in TSD 14-019 using the same process described in section 6.5.2 but replacing Basement DCGLs with soil DCGLs. There were very few positive soil sample results identified during characterization and the levels were insufficient to provide a meaningful evaluation of HTD radionuclides. Therefore, the radionuclide mixture for the Auxiliary Basement cores was applied to soil. Note that the dose contribution from HTD radionuclides at ZNPS has been shown to be trivial based on characterization to date and is expected to be trivial at license termination. Gamma emitters are directly measured during the FSS.

The IC dose percentage for soil was calculated using the Table 6-2 mixture which is considered the most representative available. As a cross-check of the Table 6-2 mixture, the IC dose was

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-50 also calculated using a mixture comprised of the data from the 10 soil samples analyzed for the initial suite. The dose from individual samples was calculated in two ways; using the mean of the MDC values and using the mean of the actual net results. Due to the fact that essentially all of the soil characterization results were non-detect, with the exception of Cs-137 at very low levels and generally in the range of background, a significant and unrealistic bias in the IC dose calculation results was introduced by the use of MDC values. To provide a more realistic evaluation of the IC dose, a separate calculation was performed using the mean of actual net results. The analysis of individual soil samples was not considered meaningful given that all of the results were less than MDC. Other than low level Cs-137, the only positive result in soil samples was Co-60 in one sample at a concentration of 0.24 pCi/g.

The IC dose percentage for soil using the Table 6-2 mixture is provided in Table 6-30. The mixture and dose percentages for the ROC are also shown in Table 6-31. The mean IC dose and IC dose percentage from the two evaluations of the soil sample mixture are listed in Table 6-31.

The IC dose percentage assuming the best estimate Table 6-2 mixture was 0.171% (Table 6-31). The IC dose calculated using the results of the 10 soil samples analyzed for the initial suite and applying MDC values for all non-detect radionuclides (i.e., essentially all radionuclides) was 9.9% (Table 6-32). The more realistic calculation of IC dose using the actual reported results from the 10 soil samples, as opposed to MDCs, resulted in an IC dose percentage of 1.96%

(Table 6-32). The actual results better correspond to the fact that the underlying assumption for the MDC calculation is that the mean net result is zero when no activity is present.

Table 6-31 Soil ROC Mixture and IC Dose Percentage Using the Table 6-2 Best Estimate Mixture.

Radionuclide Mixture Percent Percent Annual Dose Co-60 0.91%

3.878%

Ni-63 23.48%

0.119%

Sr-90 0.05%

0.072%

Cs-134 0.01%

0.028%

Cs-137 74.60%

95.733%

Insignificant Contributor Percent 0.95%

0.171%

Total 100%

100%

Table 6-32 Soil IC Dose and Dose Percentage using Soil Sample Results Data Used for Non-Detect IC Dose mrem/yr IC Dose Percentage (of 25 mrem/yr)

MDC Values 2.47 9.9%

Actual Reported Results 0.49 1.96%

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-51 The IC dose percentage for soil is considered to be between 0.17% and 1.96%. The 9.9% IC dose percentage is not considered representative of the actual site mixture due to MDC biasing issues. For example, it is very likely that the same MDC values would have been reported in the analysis of a soil sample from an offsite location, with the same calculation results. However, to ensure conservatism, an IC dose percentage of 10% will be used to adjust the ROC DCGLs for soil to conservatively account for the IC dose. The 10% (2.5 mrem/yr) value significantly exceeds the IC dose percentage calculated using the best estimate Table 6-2 mixture or the actual soil analytical results and provides a significant margin to account for uncertainty.

None of the 10 soil samples analyzed for the initial suite contained positive results for a HTD ROC, or any HTD radionuclide. Therefore, it is not technically feasible to develop radionuclide ratios for use with the surrogate approach during FSS. The maximum radionuclide ratios for Sr-90/Cs-137 and Ni-63/Co-60 calculated for the Auxiliary Basement in section 6.5.2.4 will be used in the surrogate evaluations for soil unless different values are justified by the results of continuing characterization or FSS HTD analysis results (see LTP Chapter 5 section 5.2.11).

6.8.3.

Soil Exposure Scenario and Critical Group The Resident Farmer exposure scenario and critical group as described in section 6.5.3 for the BFM also applies to the soil dose assessment. The Resident Farmer Scenario includes the following exposure pathways:

Direct exposure to external radiation

Inhalation dose from airborne radioactivity

Ingestion dose from the following pathways:

- Plants grown with irrigation water from onsite well

- Meat and milk from livestock consuming fodder from fields irrigated with onsite well water and consuming water from onsite well

- Drinking water from onsite well

- Soil ingestion 6.9.

Soil Computation Model - RESRAD v7.0 RESRAD version 7.0 was used to calculate DCGLs for surface and subsurface soil.

6.9.1.

Parameter Selection The parameters selection process described in section 6.6.3.1 and summarized in Figure 6-10 was used to select the RESRAD input parameters for soil. The vast majority of the behavioral, metabolic and physical parameters are the same as those developed for the BFM RESRAD modeling. However, the conceptual model for soil required changes to the following parameters:

Kd values for site soil (sand) were selected based on the review provided by Brookhaven National Laboratory in TSD 14-004 (see Table 6-33),

Cover depth = 0,

Time Since Material Placement parameter set to zero,

No initial contamination penetrates the saturated zone,

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-52

An unsaturated zone is assumed to be present, and

Non-dispersion groundwater model used.

Table 6-33 Distribution Coefficients for Surface and Subsurface Soil RESRAD Analysis Radionuclide Soil Kd (cm3/g)

Co-60 1161 Ni-63 62 Sr-90 2.3 Cs-134 615 Cs-137 615 6.9.2.

Uncertainty Analysis Parameter uncertainty analysis was performed following the process described in section 6.6.3.1.

The parameters used for the uncertainty analysis of the surface and subsurface soil dose modeling are the same as were used for the BFM RESRAD uncertainty analysis, with the exception of contaminated zone thickness. A 0.15 m thickness is used for surface soil and 1.0 m thickness for subsurface soil. The unsaturated zone depth was also adjusted to ensure that the depth to the water table remains constant for both the 0.15 m and 1.0 m contaminated zone thicknesses.

The RESRAD input parameters used for the uncertainty analysis of both surface and subsurface soil are provided in Attachment 3. Deterministic parameters were selected for behavioral, metabolic and Priority 3 physical parameters in accordance with the process in Figure 6-10. The majority of the Priority 1 and 2 physical parameters are assigned the parameter distributions from NUREG/CR-6697. Three site-specific Priority 1 and 2 physical parameters are assigned deterministic values in the uncertainty analysis including cover depth, precipitation, and well pumping rate (which does not have a recommended distribution in NUREG/CR-6697). The distribution coefficients were assigned either deterministic site-specific values based on the most conservative laboratory analysis of site soil as documented in TSD 14-004 or the distribution from NUREG/CR-6697 if site-specific data were not available. There are other site-specific parameters available, but these are included in the uncertainty analysis. The distributions from NUREG/CR-6697 were used to ensure that the appropriate level of justification is provided if one or more of these site-specific parameters are determined to be sensitive.

The uncertainty analysis was conservatively run for all ROC individually to maximize the number of parameters deemed sensitive. A more realistic approach would apply the radionuclide mixture fractions for ZNPS which could reduce the sensitivity of total dose to some parameters for the low abundance radionuclides. In addition, parameter input rank correlations were not applied because this also maximizes variability and corresponding parameter sensitivity. Surface soil parameters that exhibited sensitivity to dose (i.e., with a lPRCCl result greater than 0.25) are listed in Table 6-34. The PRCC values listed are the highest individual values from the three runs made in the RESRAD Uncertainty Analysis. Tables 6-35 and 6-36 provide the selected 75th

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-53 or 25th percentile deterministic values for surface soil from the NUREG/CR-6697 distributions for the positively and negatively correlated parameters, respectively.

Table 6-34 Surface Soil DCGL Uncertainty Analysis Results for Parameters with lPRCCl >0.25 Parameter PRCC Value Co-60 Cs-134 Cs-137 Ni-63 Sr-90 Depth of Soil Mixing Layer NS

-0.30

-0.36

-0.56 NS Depth of Roots

-0.30

-0.47

-0.53

-0.78

-0.90 External Gamma Shielding Factor 0.99 0.96 0.93 NS NS Density of Contaminated Zone 0.59 0.32 NS NS NS Plant Transfer Factor 0.34 0.57 0.63 0.86 0.96 Meat Transfer Factor 0.26 0.25 0.31 NS NS Milk Transfer Factor NS 0.25 0.31 0.88 0.36 Table 6-35 Selected Deterministic Values for Surface Soil DCGL Sensitive Parameters from Table 6-21 That Are Radionuclide Independent Parameter Percentile Parameter Value Depth of Soil Mixing Layer 25th 0.15 Depth of Roots 25th 1.22m External Gamma Shielding Factor 75th 0.40 Density of Contaminated Zone 75th 1.68 g/cm3 (site-specific value of 1.8 g/cm3 used)

Table 6-36 Deterministic Values for Surface Soil DCGL Sensitive Parameters from Table 6-21 that are Radionuclide Dependent Radionuclide Plant Transfer Factor 75th Percentile Meat Transfer Factor 75th Percentile Milk Transfer Factor 75th Percentile Co-60 0.15 0.058 NS Cs-134 0.078 0.065 0.014 Cs-137 0.078 0.065 0.014 Ni-63 0.092 NS 0.032 Sr-90 0.59 NS 0.0027 Subsurface soil parameters with a lPRCCl result greater than 0.25 are listed in and Table 6-37.

Tables 6-38 and 6-39 provide the selected 75th or 25th percentile deterministic values for

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-54 subsurface soil. The median of the NUREG/CR-6697 distributions was assigned to the Priority 1 and 2 parameters that were not sensitive (i.e., not listed in Tables 6-34 and 6-37). The RESRAD Uncertainty Reports for each ROC are provided in TSD 14-010.

Table 6-37 Subsurface Soil DCGL Uncertainty Analysis Results for Parameters with lPRCCl > 0.25 Parameter PRCC Value Co-60 Cs-134 Cs-137 Ni-63 Sr-90 Depth of Roots

-0.45

-0.60

-0.69

-0.86

-0.93 External Gamma Shielding Factor 0.97 0.90 0.84 NS NS Plant Transfer Factor 0.67 0.83 0.88 0.96 0.98 Meat Transfer Factor 0.40 0.29 0.37 NS NS Milk Transfer Factor NS 0.35 0.45 0.91 0.44 Table 6-38 Selected Deterministic Values for Subsurface Soil DCGL Sensitive Parameters from Table 6-28 that are Radionuclide Independent Parameter Percentile Parameter Value Depth of Roots 25th 1.22m External Gamma Shielding Factor 75th 0.40 Table 6-39 Deterministic Values for Subsurface Soil DCGL Sensitive Parameters from Table 6-28 that are Radionuclide Dependent Radionuclide Plant Transfer Factor 75th Percentile Meat Transfer Factor 75th Percentile Milk Transfer Factor 75th Percentile Co-60 0.15 0.058 NS Cs-134 0.078 0.065 0.014 Cs-137 0.078 0.065 0.014 Ni-63 0.092 NS 0.032 Sr-90 0.59 NS 0.0027 6.10. RESRAD Results and Soil DCGLs The surface and subsurface soil DCGLs were calculated using the deterministic parameter set provided in Attachment 4. The RESRAD Summary Reports are provided in TSD 14-010. The surface and subsurface soil DCGLs are provided in Table 6-40. Note that the values reported in

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-55 Table 6-40 also include adjustment to account for the 10% dose contribution from removed insignificant contributors (see section 6.8.2)

Table 6-40 Adjusted Surface Soil and Subsurface Soil DCGLs (Adjusted for IC Dose)

Radionuclide Surface Soil DCGL (pCi/g)

Subsurface Soil DCGL (pCi/g)

Co-60 4.26 3.44 Cs-134 6.77 4.44 Cs-137 14.18 7.75 Ni-63 3572.10 763.02 Sr-90 12.09 1.66 6.11. Soil Area Factors The RESRAD modeling for soil assumes a large source term area of 64,500 m2. Isolated areas of contamination that are smaller than 64,500 m2 will have a lower dose for a given concentration. The ratio of the dose from the full source term area to the dose from a smaller area is defined as the AF.

ZionSolutions TSD 14-011, Soil Area Factors (Reference 6-30), calculates Area Factors (AF) for each ROC using RESRAD. The source area sizes ranged from 0.01 m2 up to the full source area of 64,500 m2. The AFs are relatively insignificant for areas greater than 100 m2 and in practice are very unlikely to be required for greater areas. The RESRAD parameter set in was used in TSD 14-011 to generate the AFs by varying the source term areas in each run. The RESRAD Summary Reports are provided in TSD 14-011. The surface soil and subsurface soil AFs for areas up to 100 m2 are listed in Tables 6-41 and 6-42. A comprehensive list of AFs is provided in LTP Chapter 5, Table 5-16 and 5-17.

6.12. Buried Piping Dose Assessment and DCGL Buried piping is defined as pipe that runs through soil. The dose assessment methods and resulting DCGLs for buried piping are described in detail in ZionSolutions TSD 14-015, Buried Pipe Dose Modeling & DCGLs (Reference 6-4). This section summarizes the methods and provides the resulting DCGLs for buried pipe.

As discussed in section 6.14, the maximum dose from buried piping will be added to the maximum dose from the open land survey unit(s). The rationale for this approach is identical to the standard process presented in MARSSIM for accounting for dose from elevated areas of residual radioactivity within an open land survey unit.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-56 Table 6-41 Surface Soil Area Factors Area (m2)

Area Factors for Radionuclides of Concern Cs-137 Co-60 Cs-134 Ni-63 Sr-90 1

1.50E+01 1.23E+01 1.33E+01 8.06E+03 8.90E+02 3

6.46E+00 5.24E+00 5.73E+00 2.73E+03 3.13E+02 10 3.06E+00 2.47E+00 2.72E+00 8.23E+02 1.03E+02 30 2.10E+00 1.68E+00 1.86E+00 2.75E+02 4.02E+01 100 1.62E+00 1.29E+00 1.44E+00 8.26E+01 1.64E+01 Table 6-42 Subsurface Soil Area Factors Area (m2)

Area Factors for Radionuclides of Concern Cs-137 Co-60 Cs-134 Ni-63 Sr-90 1

2.04E+01 1.10E+01 1.52E+01 6.49E+03 1.50E+03 3

9.26E+00 4.91E+00 6.92E+00 2.17E+03 5.23E+02 10 4.48E+00 2.36E+00 3.35E+00 6.51E+02 1.64E+02 30 3.23E+00 1.70E+00 2.42E+00 2.17E+02 5.72E+01 100 2.59E+00 1.37E+00 1.95E+00 6.51E+01 1.76E+01 6.12.1. Buried Pipe Source Term and Radionuclides of Concern Buried piping, with internal diameters ranging from one inch to 48 inches is expected to remain at the time of license termination. The Circulating Water Intake Pipes and Circulating Water Discharge Tunnels (and associated Discharge Tunnel Pipe located in the Turbine Building) are not considered buried pipe. The dose from residual radioactivity that is assumed to remain in the Intake Pipe and Discharge Tunnel is accounted for by adding the surface area (representing source term) to the applicable Basement in the DCGL calculation. The list of buried piping expected to remain is provided in TSD 14-016 (Reference 6-3).

The list of end-state buried pipe presented in TSD 14-016 is meant as a bounding condition. No pipe that is not listed in TSD 14-016 will be added to the end-state condition however, pipe can be removed from the list and disposed of as waste. As discussed below, the Buried Pipe DCGL is based on the summation of the surface area of all pipe to ensure conservatism regardless of the pipe location. Decreasing the amount of Buried Pipe to remain, i.e., removing more pipe than currently planned, would decrease the source term and corresponding dose. The DCGL becomes more conservative if less than 2,153 m2 of pipe surface area remains and therefore no DCGL revision is necessary if additional pipe is removed.

None of the listed buried piping was associated with systems involving reactor coolant. Based on process knowledge, the majority of piping is expected to contain minimal residual radioactivity at levels well below the DCGLs.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-57 To date, samples from piping systems have not been collected. Therefore, ZSRP is currently using the results of Auxiliary Basement concrete cores to represent the ROC and mixture for buried piping (see Table 6-3). Buried piping will be characterized as part of the continuing characterization program in accordance with LTP Chapter 2 section 2.5.

6.12.2. Buried Pipe Exposure Scenario and Critical Group The critical group for the buried piping dose assessment is the Resident Farmer.

The buried pipe DCGL is determined for two scenarios; assuming that all pipe is excavated and assuming that all pipe remains in situ. Although unrealistic, for the purpose of the bounding modeling approach used, the dose from the two scenarios is summed to determine the Buried Pipe DCGL.

The excavation scenario assumes that all buried pipe is excavated and all activity on the internal surfaces of the pipes instantly released and mixed with surface soil. The in situ scenario assumes that all of the buried piping remains in the as-left condition at the time of license termination and that all activity is instantly released to adjacent soil. Two separate in situ calculations were performed. The first assumes that all pipes are located at 1 m below the ground surface and the second assumes that all pipes are located in the saturated zone.

6.12.3. Buried Pipe RESRAD Model for Excavation Scenario The Excavation scenario assumes that all of the buried piping is excavated, brought to the surface and spread over a contiguous area equal to the internal surface area of the pipe. After being brought to the surface all of the activity on the internal surfaces of the pipe is assumed to instantly release and mix in a 0.15 m depth of surface soil.

RESRAD modeling is used to determine the dose from excavated buried pipe in units of mrem/yr per pCi/g. The RESRAD parameters used are the same as those used for surface soil DCGLs (see Attachment 4) with the following exceptions:

Area of Contaminated Zone 2153 m2

Length Parallel to Flow SFP/Transfer Canal 46 m

Cover Depth 0 m

Unsaturated Zone Thickness 3.45 m The Area of Contaminated Zone parameter is equal to the total internal surface are of all buried pipe. The complete list of buried pipe and total surface internal surface area is provided in Reference 6-4, Attachment 1. The length parallel to flow is the square root of the contaminated area under a nominal assumption that the shape of the contaminated area is square. The bases for the remaining parameters are self-explanatory. Note that the buried pipe list was revised after the RESRAD runs were made (the de-icing lines were initially listed twice). The total internal surface area was reduced from 2153 m2 to 1539 m2. The reduced area results in lower dose to source ratios (DSRs) (mrem/yr per pCi/g) and therefore the DSRs using 2153 m2 were retained and used to calculate the Buried Pipe DCGLs which is conservative. Using the larger surface area also provides margin to account for the potential for additional buried pipe to be identified and added to the Reference 6-4, Attachment 1 list as decommissioning proceeds. Although not expected, if additional buried pipe is identified and added to the list, and the total surface area is

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-58 increased but remains below the 2153 m2 assumed in the RESRAD model, the calculated buried pipe DCGLs would remain conservative. The area revision (and associated conservatism) also applies to the Insitu Saturated and Insitu Unsaturated scenarios RESRAD runs described in section 6.12.4.

6.12.4. Buried Pipe RESRAD Model for Insitu Scenarios The Buried Pipe Insitu scenarios assume that the pipe remains in place. Two in situ geometries are evaluated. One scenario assumes that the buried pipe is in the unsaturated zone and a second scenario assumes that the pipe is in the saturated zone.

For the Insitu Unsaturated Zone scenario, the pipes are assumed to be located 1 m below the ground surface. The ZSRP decommissioning approach calls for removal of all material, including piping, to 3 feet below grade. Note that portions of the storm drain system that will remain in place and functional after license termination are closer to the surface than 1 m but this minor exception is considered insignificant. Assuming that the pipe is within 1m of the surface allows the roots to penetrate the 0.15 m thick in situ source which maximizes dose.

The RESRAD parameters used for the Buried Pipe Unsaturated Zone Insitu scenario are the same as those used for surface soil DCGLs (see Attachment 4) with the following exceptions:

Area of Contaminated Zone 2153 m2

Length Parallel to Flow 46 m

Cover Depth 1 m

Unsaturated Zone Thickness 2.45 The second in situ scenario evaluated assumed that all buried pipe is in the saturated zone. This scenario is intended to conservatively address the possibility that GW could possibly enter some portions of the buried piping.

The RESRAD parameters used for the Buried Pipe Saturated Zone Insitu scenario are the same as those used for surface soil DCGLs (see Attachment 4) with the following exceptions:

Area of Contaminated Zone 2153 m2

Length Parallel to Flow 46 m

Cover Depth 3.6 m

Unsaturated Zone Thickness 0 m

Contaminated Fraction Below the Water Table 1

All Kds set to minimum site-specific value since dose is 100% from water pathways 6.12.5. Buried Pipe Uncertainty Analysis An uncertainty analysis was performed for the three Buried Pipe dose scenarios to identify parameters that are sensitive in the Buried Pipe scenarios that were not identified as sensitive in the soil dose modeling uncertainty analysis. The process and criteria used to identify sensitive parameters and select conservative deterministic parameters were the same as that describe in Figure 6-10.

The RESRAD parameters assigned for the uncertainty analysis are the same as those used for the soil uncertainty analysis listed in Attachment 7 with a few exceptions:

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-59

The Buried Pipe scenario parameters listed in section 6.12.4 were used as opposed to the corresponding soil parameters.

Kd distributions were included to represent the range of site-specific sand Kd values determined by laboratory analysis

To allow the dose from plant ingestion to vary with contaminated zone area, the two plant ingestion rate parameters were doubled to account for the fact that RESRAD automatically divides the entered ingestion rates by a factor of 2 when a value of -1 is used for the Contaminated Fraction of Plant Food parameter. The modified parameters are:

o Fruits, non-leafy vegetables, grain consumption (kg/y) = 224 o Leafy vegetable consumption (kg/y) = 42.8 The only parameters that required change as a result of the uncertainty analysis were the Saturated Zone Hydraulic Gradient for the Insitu Saturated scenario and the Depth of Roots for the Insitu Unsaturated scenario. All of the remaining parameters identified as sensitive in Reference 6-4, Table 1 were already identified as sensitive, with the same correlation, in the soil DCGL sensitivity analyses. The corresponding parameters, either 25th or 75th percentile, were included in the baseline surface soil DCGL deterministic parameter sets used for the Buried Pipe RESRAD runs.

The sensitivity of the assumed source term thickness required a separate analysis. The buried pipe scenarios assume that residual radioactivity is released from the pipes into adjacent soil. The thickness of soil into which the released activity was assumed to mix was 0.15 m which is considered the minimum reasonable mixing depth, particularly for the excavation scenario. As the Thickness of Contaminated Zone parameter is increased, assuming a unit concentration for all radionuclides, the dose increases. However, as the contaminated zone thickness increases the source term concentration decreases as an inverse linear function of the mixing depth. To determine the effect of these conflicting effects of increasing the Thickness of Contaminated Zone a separate sensitivity analysis was performed that accounts for both effects for source term thicknesses of 0.15 m and 1.0 m.

Reference 6-4, Attachment 3 provides the results of the sensitivity analysis. Note that for all scenarios and all radionuclides except Sr-90 increasing the Thickness of Contaminated Zone either has no effect on dose (indicated by a value of 1 in the column labeled DSR Ratio*Source Term Decrease in the Reference 6-4, Attachment 3 Tables) or causes the dose to decrease (indicated by a fraction in the column labeled DSR Ratio*Source Term Decrease in Reference 6-4, Attachment 3 Tables). The one exception, i.e., Sr-90, showed an 8% increase in dose at a 1 m source term depth for the Insitu Saturated scenario and a 13% increase at 1 m depth for the Excavation Scenario.

For the Insitu Saturated Scenario, increasing the source term thickness had no effect on dose for any radionuclides other than Sr-90. Note that the actual dose impact from the slightly increased Sr-90 dose for a 1 m thick source, as opposed to 0.15 m, is much lower than the values calculated individually for Sr-90 when the mixture percentages are considered. As shown in LTP Chapter 5, Table 5-2, the Auxiliary Basement mixture fraction (which is assumed to apply to buried pipe) for Cs-137 is 75.32% while the mixture fraction for Sr-90 is 0.05%. Therefore, the actual fractional dose attributable to the 8% and 20% increased values can be approximated as the ratio

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-60 of percentages times the percentage increase, i.e., 1.08*0.05/75.32 and 1.13 *0.05/75.32, or 0.07% and 0.08% of the final compliance dose which is insignificant.

For the excavation scenario, there are conflicting results for Sr-90 and the gamma emitters.

While the Sr-90 dose shows an increase of 13% for the 1 m depth the Cs-137 dose decreases by 79%. When the mixture fractions are considered it is clear that the decrease in Cs-137 dose at 1 m source term depth would be orders of magnitude greater than the slight Sr-90 increase which would result in a non-conservative dose calculation.

In conclusion, the Thickness of Contaminated Zone parameter was set to 0.15 for all scenarios.

However, to account for the indicated dose increase for Sr-90 at 1 m depth DSRs for Sr-90 were increased by factors of 1.08 and 1.13 for the Insitu Saturated and Excavation scenarios, respectively.

6.12.6. Buried Pipe RESRAD Results Three RESRAD runs were performed for Buried Pipe; Excavation Scenario, Insitu Unsaturated Scenario, and Insitu Saturated Scenario (Reference 6-4). The RESRAD DSR results are summarized in Table 6-43.

Table 6-43 RESRAD DSR Results for Buried Pipe Dose Assessment to Support DCGL Development Radionuclide Excavation (mrem/yr per pCi/g)

Insitu Unsaturated (mrem/yr per pCi/g)

Insitu Saturated (mrem/yr per pCi/g)

Co-60 4.975E+00 7.298E-02 5.710E-04 Cs-134 2.836E+00 1.070E-01 2.881E-03 Cs-137 1.238E+00 8.491E-02 2.287E-03 Ni-63 1.445E-03 1.285E-03 2.745E-04 Sr-90 (1) 1.489E+00 1.384E+00 1.480E+00 (1) The Sr-90 DSRs for Excavation and Insitu Saturated were multiplied by factors of 1.13 and 1.08, respectively, to adjust for potentially higher dose from thicker source terms (Reference 6-3) 6.12.7. Buried Piping DCGL The Buried Pipe DCGL is determined by first calculating the pCi/g concentration in the 0.15 m soil mixing layer that corresponds to a unit concentration, 1 dpm/100 cm2, on the pipe surface.

The second input to the DCGL calculation is the sum of the DSR for Excavation and the maximum DSR for the Insitu Scenarios. As seen in Table 6-43, the maximum Insitu DSR is from the Unsaturated Scenario for all radionuclides except Sr-90. Therefore, the DSR summation used in the Buried Pipe DCGL calculation is comprised of the Excavation and Insitu Unsaturated Scenario DSRs for all radionuclides except Sr-90 which is based on the summation of the Excavation and Insitu Saturated Scenario DSRs. The summed DSRs are shown in Table 6-44.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-61 Table 6-44 Maximum Summed RESRAD DSRs from Excavation and Insitu Scenarios Radionuclide Maximum Summed DSR Excavation + Insitu (mrem/yr per pCi/g)

Co-60 5.048E+00 Cs-134 2.943E+00 Cs-137 1.323E+00 Ni-63 2.730E-03 Sr-90 2.969E+00 The dpm/100 cm2 per pCi/g conversion factor is used with the maximum summation DSR in Table 6-43 to calculate the Buried Pipe DCGL as shown in Equation 6-8.

Equation 6-8 2U )*+,

1 49V 5OPP7M )5W MXP 100 6PY

X*; [

25 P:7P \\:

where:

BP DCGL

= Buried Pipe DCGL (dpm/100 cm2)

Max Summed DSR = Maximum Summed DSR values from Table 6-43 (pCi/g per mrem/yr)

(dpm/100 cm2)/pCi/g = dpm/100 cm2 in pipe per pCi/g in soil The calculation of Buried Pipe DCGLs is provided in Reference 6-4, Attachment 2. Table 6-45 provides the resulting Buried Pipe DCGLs.

Table 6-45 Buried Piping DCGLs (Not Adjusted for IC Dose)

Radionuclide Buried Pipe DCGL (dpm per 100 cm2)

Co-60 2.94E+04 Cs-134 5.04E+04 Cs-137 1.12E+05 Ni-63 5.44E+07 Sr-90 5.00E+04 6.12.8. Adjustment for Dose from Insignificant Contributors The buried pipe DCGLs must be adjusted to account for the radionuclides in the initial suite that were removed due to insignificant dose contribution. The Excavation scenario is closely related to the soil DCGL scenario. The Buried Pipe Insitu scenarios, particularly the Insitu Saturated,

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-62 have a greater potential groundwater dose contribution than the soil DCGL scenario and are more closely related to the BFM scenarios. The activity in buried pipes originate in one of the basements and the activity is assumed to mix with basements as well as mix with soil.

Therefore, the insignificant dose contribution percentage assigned for the Buried Pipe DCGL adjustment was the maximum for either soil or the BFM. The maximum IC dose percentage was 10% for both soil and the BFM (Containment) and was the value used for Buried Pipe DCGL adjustment.

The Adjusted Buried Pipe DCGLs are provided in Table 6-46.

Table 6-46 Adjusted Buried Pipe DCGLs (Adjusted for IC Dose)

Radionuclide Adjusted Buried Pipe DCGL (dpm/100 cm2)

Co-60 2.64E+04 Cs-134 4.54E+04 Cs-137 1.01E+05 Ni-63 4.89E+07 Sr-90 4.50E+04 6.13. Embedded Piping DCGL Embedded piping is defined as piping that runs vertically in a concrete wall or horizontally in a concrete floor. The residual radioactivity in embedded piping to remain has no release pathway other than into the Basement(s) where the piping terminates. Each embedded pipe run is treated as a separate survey unit within the basement that the embedded pipe is located and the DCGL calculated accordingly.

The embedded pipe to remain in the End State is identified and quantified in TSD 14-016. The embedded pipe survey units are listed in Table 6-47 along with the total internal survey area of the pipes in the survey unit. The IC-sump embedded pipe is very limited with a total surface area of 1.05 m2 each for Unit 1 and Unit 2. To provide a reasonable maximum value for the DCGL a nominal area of 100 m2 was assumed for the surface area of IC sump embedded pipe survey unit. The U2 Steam Tunnel surface area was slightly lower than the U1 area (46.88 m2 versus 46.39 m2). For simplicity, the higher, more conservative, area was applied to both Steam Tunnel Floor Drain DCGL calculations.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-63 Table 6-47 Embedded Pipe Survey Unit Surface Areas Embedded Pipe EP SU Surface Area (m2)

Auxiliary Floor Drains 299.41 Turbine Floor Drains 302.43 U1 Containment IC-Sump Drain 1.05 (100) (1)

U2 Containment IC-Sump Drain 1.05 (100) (1)

U1 Steam Tunnel Floor Drain 46.88(2)

U2 Steam Tunnel Floor Drain 46.88(2)

U1 Tendon Tunnel Floor Drain 51.41 U2 Tendon Tunnel Floor Drain 51.41 (1) The total surface area of unit 1 and unit 2 IC Sump Drains are 1.05 m2 each. To provide a reasonable maximum value for the DCGL a nominal area of 100 m2 was assumed for the DCGL calculation.

(2) Higher surface area applied to both U1 and U2 Steam Tunnel Floor Drains. U2 area is 46.39 m2.

DCGLs were calculated for each of the embedded pipe survey units using Equation 6-9.

Equation 6-9

)*+,]^_, ;

25 234 )3@,/

1 HU 5` ?:79 1H09 K* )<L7 396Q<:

Where:

DCGLEP (b,i)

= Embedded Pipe DCGL for radionuclide (i) in basement (b)

(pCi/m2)

BFM DF (b,i)

= Summation of Basement Fill Model Dose Factors for Groundwater and Drilling Spoils scenarios for radionuclide (i) in basement (b) (mrem/yr per mCi) 25

= 25 mrem/yr release criterion EP SU Area

= Total internal surface area of all embedded pipe in the survey unit (m2) 1E+09

= conversion factor of 1E+09 pCi/mCi IC Dose Factor

= Insignificant contributor dose adjustment factor equal to 0.90 for Tendon Tunnel and IC-Sump embedded pipe and 0.95 for remaining embedded pipe (see section 6.5.2.3)

The embedded pipe DCGL calculations are provided in Reference 13. Note that the Tendon Tunnel Floor drains are included in both the Containment and Turbine Basement compliance demonstrations (see LTP Rev 1, Chapter 5, Table 5-20). The embedded pipe DCGL was therefore calculated for both basements. The DCGLs calculated using the Containment Basement Dose Factors in Equation 6-9 were lower than using the Turbine Basement Dose Factors and

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-64 were therefore assigned as the Tendon Tunnel floor drain DCGLs. The embedded pipe DCGLs are provided in Table 6-48.

Table 6-48 Embedded Pipe DCGLEP (Adjusted for Insignificant Contributor Dose)

Radionuclide Auxiliary Floor Drain Turbine Floor Drain IC-Sump Drain U1 and U2 Steam Tunnel Floor Drain U1 and U2 Tendon Tunnel Floor Drains U1 and U2 (pCi/m2)

(pCi/m2)

Co-60 7.33E+09 6.31E+09 5.47E+09 4.07E+10 1.06E+10 Cs-134 5.10E+09 1.43E+09 1.05E+09 9.22E+09 2.04E+09 Cs-137 2.68E+09 1.89E+09 1.37E+09 1.22E+10 2.67E+09 Ni-63 2.78E+11 1.96E+11 1.40E+11 1.26E+12 2.72E+11 Sr-90 2.41E+08 6.94E+07 4.98E+07 4.48E+08 9.70E+07 H-3 NA NA 8.28E+09 NA 1.61E+10 Eu-152 NA NA 1.28E+10 NA 2.48E+10 Eu-154 NA NA 1.11E+10 NA 2.16E+10 6.13.1. Dose Calculation for Grouted Auxiliary Basement Floor Drains The FSS of the Auxiliary Basement floor drains is complete and documented in Zion Station Restoration Project Final Status Survey Release Record Auxiliary Building 542 ft Embedded Floor Drain Pipe Survey Unit 051198A. After NRC review of the Release Record the drains were grouted to refusal.

The Auxiliary Drain FSS applied the DCGLs listed in Table 6-48 which assume that activity is released from the drains at the same rate as from the floor or wall surfaces in the Auxiliary Basement. A dose calculated using the Table 6-48 DCGL values is highly conservative because it does not take credit for the reduction in release due to the presence of grout. Therefore, a more realistic, yet still reasonably conservative dose calculation is performed for the Auxiliary Floor Drains that accounts for the presence of grout and will be used use in the final demonstration of compliance with the dose criterion (see section 6.17).

The reduction in radionuclide release from the Auxiliary Floor Drains due to the presence of grout was calculated in Attachment F of TSD 14-009, Revision 3, Brookhaven National Laboratory: Evaluation of Maximum Radionuclide Groundwater Concentrations for Basement Fill Model (Reference 6-18). Reduction in radionuclide release is linearly correlated to reduction in dose. The calculation assumed a one foot length of grout in the pipe and that all the residual radioactivity in the pipe is located directly under the one foot grout layer. This is very conservative given that the length of the floor drain sections range from 18 to 188 feet and the entire drain system was grouted to refusal. The vast majority of the activity in the pipes would have a much longer length of grout to diffuse through than 1 foot. The minimum depth to an identified obstruction in a grouted pipe (which may or may not cause refusal of grout flow) was

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-65 six feet. The fractional release of total residual radioactivity remaining in the Auxiliary Floor Drain pipe for each ROC, assuming a one foot length of grout, is provided in Table 6-49.

Table 6-49 Fractional Release of Residual Radioactivity from Auxiliary Floor Drains Due to presence of 1 Foot of Grout Radionuclide Fractional Release (1)

Co-60

<1E-30 Ni-63 8.28E-07 Sr-90 1.19E-16 Cs-134 1.38E-25 Cs-137 4.98E-07 (1) From TSD 14-009, Revision 3, Attachment F (Reference 6-18)

The maximum fractional release for all ROC occurs for Ni-63 with a value of 8.28E-07. As a measure of conservatism in the assumption of a one foot grout length, the fractional release was also calculated for grout lengths of two and four feet resulting in much lower Cs-137 fractional release values of 1.24E-13 and 2.31E-29, respectively. The dose from Ni-63 calculated in the Release Record for the Auxiliary Floor Drains, assuming no grout, would therefore be reduced by at least a factor of 8.28E-07 when grout is accounted for. The dose from the other ROC would be reduced further as indicated by the lower fractional releases in Table 6-49.

Based on the FSS results and the DCGLs in Table 6-48, the total dose including all ROC was calculated in the FSS Release Record for the Auxiliary Building Floor Drains to be 4.241 mrem/yr. Using the highest fractional release from Table 6-49 of 8.28E-07, a conservative estimate of dose, including the effect of diffusion through grout, is 4.241 mrem/yr x 8.28E-07 =

3.51E-06 mrem/yr.

The dose calculation of 3.51E-06 mrem/yr accounts for the fractional release of the ROC and includes a general assumption that the fractional release of the HTD radionuclides included in the DCGL adjustment for insignificant contributor dose (see Equation 6-9) would be also be a very low. However, a review of Reference 6-18 shows that the fractional release for H-3 is 0.34 (the value was much lower for Eu-152 and Eu-154 at <1E-30). While the higher fractional release is not unexpected for H-3, which has a diffusion coefficient that is approximately two orders of magnitude higher than Cs-137, it raises a general question as to the actual fractional release for the insignificant contributor radionuclides. To address this question in a simple, highly conservative and bounding manner, the dose from insignificant contributors is calculated without application of a grout fractional release factor, i.e., assuming no grout is present. This calculation of dose from the insignificant contributor radionuclides is in addition to the 5%

adjustment for insignificant contributor dose already included in the DCGL calculation (see Equation 6-9) and therefore included in the 3.51E-06 mrem/yr dose calculation accounting for the presence of grout.

The insignificant contributor dose percentage used in the calculation was based on HTD analysis of sediment samples collected from the Auxiliary Floor Drains prior to FSS. As shown in

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-66 of the FSS Release Record for the Auxiliary Building Floor Drains, the dose percentage assigned to the insignificant contributor radionuclides is 3.952%. Therefore, the bounding dose from the insignificant contributors alone, with no credit for grout, would be 3.952% of the 4.241 mrem/yr that was calculated assuming no grout present. This results in a dose of 0.0392*4.241mrem/yr = 0.17 mrem/yr.

In conclusion, the total dose to be assigned to the Auxiliary Building Floor Drains for the compliance calculation in section 6.17 is 3.51E-06 mrem/yr + 0.17 mrem/yr = 0.17 mrem/yr with rounding. ZSRP will add insignificant radionuclide dose in this same manner for any other end-state Class 1 embedded pipe that is grouted.

6.14. Penetration DCGL A penetration is defined as a pipe (or remaining pipe sleeve, if the pipe is removed, or concrete, if the pipe and pipe sleeve are removed) that runs through a concrete wall and/or floor, between two buildings, and is open at the wall or floor surface of each building. A penetration could also be a pipe that runs through a concrete wall and/or floor and opens to a building on one end and the outside ground on the other end.

A penetration survey unit is defined for each basement. The direction that the residual radioactivity will migrate into a given basement, cannot be predicted with certainty. Therefore, each penetration that begins in one basement and ends in another will be included in the survey units for both basements. The residual radioactivity in the penetration is assumed to release to both basements simultaneously.

The penetration DCGL (DCGLPN) is calculated in the same manner as embedded pipe using Equation 6-9 but replacing the embedded pipe survey unit surface area with the penetration survey unit surface area. The penetration survey units are defined in TSD 14-016 including the total area of each penetration survey unit as listed in Table 6-50.

Table 6-50 Penetration Survey Unit Surface Areas Embedded Pipe Penetration Survey Unit Surface Area (m2)

Auxiliary Basement 948.75 Containment Basement 242.36 Turbine Basement 1081.14 SFP/Transfer Canal 337.45 Crib House/Forebay 1.14 WWTF 0.89 An additional adjustment is required for the calculation of the DCGLPN for the Auxiliary Basement penetration survey unit. The release of residual radioactivity from the Auxiliary basement concrete assumes diffusion release. In most cases the remaining penetrations will be either the remaining pipe or steel pipe sleeve after a pipe is removed. Because the residual

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-67 radioactivity is not contained at depth in concrete, the assumption of diffusion release through concrete is not applicable and instant release is conservatively assumed for the penetrations. As seen in Equation 6-9, the penetration DCGL calculation uses the BFM Dose Factors, which in the case of the Auxiliary basement are based on an assumption of diffusion release.

An adjustment is therefore required to account for the higher maximum release rate under an instant release assumption as compared to diffusion release. The correction factor was calculated in TSD14-009, Revision 3, Attachment G, where the maximum concentration in the Auxiliary Basement under an instant release assumption was compared to the maximum concentration using a diffusion release assumption. The adjustment factor was calculated as the ratio of maximum instant release to maximum diffusion release. The results from TSD 14-009, Revision 3, Attachment G are reproduced in Table 6-51.

Table 6-51 Ratio of Instant Release Maximum to Diffusion Release Maximum for Auxiliary Basement Radionuclide Auxiliary Floor Drain Co-60 26.23 Cs-134 4.91 Cs-137 1.37 Ni-63 14.96 Sr-90 19.1 H-3 1.01 Ni-63 1.29 Sr-90 3.15 The DCGLPN for the Auxiliary Basement penetration survey unit is then calculated using Equation 6-10 which is the same as Equation 6-9 with an additional term, i.e., RatioID, to account for instant release from Auxiliary Basement penetration survey unit to the Auxiliary basement.

Equation 6-10

)*+,]^?, ;

25

234 )3ab; 234 )3BE; W9Q;<cd

1 UHe 5` ?:79 1H09 K* )<L7 396Q<:

Where:

DCGLEP (A,i)

= Embedded Pipe DCGL for radionuclide (i) in Auxiliary basement (A) (pCi/m2)

BFM DFgw (i)

= Basement Fill Model Groundwater Dose Factor for radionuclide (i) in Auxiliary basement (b) (mrem/yr per mCi)

BFM DFds (i)

= Basement Fill Model Drilling Spoils Dose Factor for radionuclide (i) in Auxiliary basement (b) (mrem/yr per mCi)

RatioID

= ratio of instant release maximum concentration to diffusion release concentration

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-68 25

= 25 mrem/yr release criterion PEN SU Area

= Total internal surface area of Auxiliary Basement penetration survey unit (m2) 1E+09

= conversion factor of 1E+09 pCi/mCi IC Dose Factor

= Insignificant contributor dose adjustment factor equal to 0.90 for Containment and 0.95 for all other basements (see LTP Chapter 6 section 6.8.2)

The penetration DCGLPN are calculated in Reference 13. The DCGLPN values are provided in Table 6-52. Note that the DCGLPN for the Crib House/Forebay and WWTF are listed as not applicable due the very small surface areas of the few penetrations present (1.14 m2 and 0.89 m2). The Crib House/Forebay and WWTF penetrations DCGLs are set equal to the wall/floor surface DCGL and included with the Crib House/Forebay and WWTF surface survey units.

Table 6-52 Adjusted Penetration DCGLPN (adjusted for insignificant contributor dose)

Nuclide Auxiliary (pCi/m2)

Containment (pCi/m2)

SFP/

Transfer Canal(1)

(pCi/m2)

Turbine (pCi/m2)

Crib House/

Forebay1 (pCi/m2)

WWTF (pCi/m2)

Co-60 8.82E+07 2.26E+09 4.45E+08 1.76E+09 NA NA Cs-134 3.28E+08 4.32E+08 7.48E+08 4.00E+08 NA NA Cs-137 6.17E+08 5.66E+08 1.46E+09 5.29E+08 NA NA Eu-152 3.29E+08 5.26E+09 9.44E+08 4.06E+09 NA NA Eu-154 2.33E+08 4.58E+09 8.53E+08 3.58E+09 NA NA H-3 3.99E+09 3.42E+09 4.84E+16 3.23E+09 NA NA Ni-63 6.79E+10 5.78E+10 1.86E+14 5.48E+10 NA NA Sr-90 2.41E+07 2.06E+07 9.26E+10 1.94E+07 NA NA (1) The DCGLPN for the Crib House/Forebay and WWTF are listed as not applicable due the very small surface area of the penetrations present. These penetrations are included with the Crib House/Forebay and WWTF surface survey units and the surface DCGLB will apply.

6.15. Existing Groundwater Dose As previously stated, no groundwater contamination has been identified by groundwater monitoring performed as of the date of this LTP (Revision 1) and is not expected to be present at the time of license termination. However, if groundwater contamination is identified during decommissioning, the dose will be calculated using the BFM Groundwater Exposure Factors in Table 6-18. Table 6-18 was developed as a part of the BFM, but the BFM Groundwater Exposure Factors presented in Table 6-18 are fully applicable to any groundwater contamination, regardless of the location.

6.16. Clean Concrete Fill ZSRP will demonstrate that all concrete designated as backfill material in basements is clean through the Unconditional Release Survey (URS) program at Zion presented in ZionSolutions procedure ZS-LT-400-001-001, Unconditional Release of Materials, Equipment and Secondary

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-69 Structures. Materials unconditionally released from Zion, regardless of their point of origin on the site, have been verified to contain no detectable plant-derived radioactivity and are free to be used and relocated anywhere offsite without tracking, controls, or dose considerations.

Although the concrete debris to remain onsite and used as clean fill can be viewed as having a no dose impact, a dose value will be assigned for the purpose of demonstrating compliance with 10 CFR 20.1402 in the same manner as other materials to remain at license termination that are surveyed and found to not contain detectable activity. The detection limit used for the dose calculation is conservatively assumed to be the maximum scan MDC of 5,000 dpm/100 cm2 allowed in the URS program. Actual detection limits in the unconditional release program are lower than this value.

The vast majority of clean concrete fill to be used will come from five buildings; Containment, Turbine, Crib House/Forebay, Service Building and Interim Waste Storage Facility. Because the concrete will be from both Containment and other structures the dose calculation was performed using both the Containment and Auxiliary ROC mixtures. The dose was essentially the same for both mixtures but the dose with the Containment mixture was slightly higher (with trivial exception of WWTF). Consistent with the bounding approach used for the clean concrete assessment, the Containment mixture was applied to all concrete. In addition, when applying the ROC mixture, the 5,000 dpm/100 cm2 maximum detection limit was assumed to be 100% Cs-137. The remaining radionuclide concentrations were added to the Cs-137 concentration at their respective ratios to Cs-137.

The dose values are calculated separately for each basement assuming that the entire basement void is filled with concrete only. This conservatively includes the top three feet of fill which will be soil for all basements and not concrete. Details regarding the calculation are provided in Reference 13, section 8. The total dose results for each basement, assuming a scan MDC value of 5,000 dpm/100 cm2 and including all ROC, are provided in Table 6-53.

The dose values in Table 6-53 will be adjusted based on the actual maximum scan MDC after all URS surveys are completed. The adjusted dose will be calculated by multiplying the ratio of the actual maximum scan MDC to 5,000 dpm/100 cm2 by the values in Table 53. The adjusted dose will be added to any basement where concrete fill is used regardless of the volume of concrete fill used. This is a conservative and bounding approach (see section 6-17).

Table 6-53 Dose Assigned to Clean Concrete Fill Auxiliary Containment SFP/

Transfer Canal Turbine Crib House/

Forebay WWTF Dose (mrem/yr) 9.94E-01 1.77E+00 1.52E-01 1.58E+00 1.57E+00 6.40E+00 6.17. Demonstrating Compliance with Dose Criterion There will be four distinct source terms in the ZNPS End State; backfilled basements, soil, buried piping, and groundwater. Demonstrating compliance with the Dose Criterion requires the summation of dose from the four source terms as shown in Equation 6-11. The embedded pipe dose, penetration dose and clean concrete fill dose (see sections 6.13, 6.14, and 6.16

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-70 respectively) will be added to the dose from wall and floor surfaces in the applicable basement to calculate the total basement dose. See LTP Chapter 5, Table 5-20 for a list of embedded pipe and penetration survey units and which basement they associated with. The maximum total basement SOF will be used for the Max SOFBASEMENT term in Equation 6-11.

The dose summation described in Equation 6-11 is conservative because the various source terms are likely not contiguous or simultaneous. For example, the maximum open land soil survey unit dose could be from an area that is not within the footprint of the Basement assigned with the maximum dose. Another example is the buried pipe that delivers the greatest dose may not be under or contiguous with the open land survey unit assigned with the maximum dose.

The final compliance dose will be calculated using Equation 6-11 after FSS has been completed in all survey units. The Release Record for each FSS unit will be reviewed to determine the maximum mean dose from each for each of the four source terms (e.g. basement, soil, buried pipe and existing GW if applicable). The compliance dose must be less than or equal to 25 mrem/yr. The calculation of the compliance dose will be documented in the final FSS Report for the site.

A detailed description of the terms in Equation 6-11 and the process for calculating the Compliance Dose is provided in ZionSolutions TSD 17-004,"Operational Derived Concentration Guideline Levels for Final Status Surveys" (Reference 6-31). The Operational DCGLs selected in TSD 17-004 are less than the standard DCGLs calculated in this chapter. The application of the Operational DCGLs provides additional assurance that the compliance dose will be less than or equal to 25 mrem/yr after FSS is completed for all four source terms. See LTP Chapter 5 for additional information on the application of Operational DCGLs during FSS.

Equation 6-11 fghijklmno pgqo

rls tuvwxtyryz{ rls tuvtul} rls tuvw~?lyp ly

rls tuv?u~zpx{y? hoh/

where:

Compliance Dose

=

must be less than or equal to 25 mrem/yr, Max SOFBASEMENT

=

Maximum Sum of Fractions (SOF) (mean of FSS systematic results plus the dose from any identified elevated areas) for backfilled Basement FSS unit (including surface, embedded pipe, penetrations and fill [if required]),

Max SOFSOIL

=

Maximum SOF (mean of FSS systematic results plus the dose from any identified elevated areas) for open land survey units, Max SOFBURIED PIPE

=

Maximum SOF (mean of FSS systematic results plus the dose from any identified elevated areas) from buried

piping, Max SOFGROUNDWATER=

Maximum SOF for from existing groundwater

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-71 6.18. References 6-1 ZionSolutions Technical Support Document 14-003, Revision 3, Conestoga Rovers &

Associates (CRA) Report, Zion Hydrogeologic Investigation Report 6-2 Zion Nuclear Power Station, Units 1 and 2 Asset Sale Agreement - December 2007 6-3 ZionSolutions TSD 14-016, Revision 0, Description of Embedded Piping, Penetrations and Buried Piping to Remain in Zion End State 6-4 ZionSolutions Technical Support Document 14-015, Revision 3, Buried Pipe Dose Modeling & DCGLs 6-5 Zion Station Historical Site Assessment (HSA) - September 2006 6-6 U.S. Nuclear Regulatory Commission NUREG-1757, Volume 2, Revision 1, Consolidated Decommissioning Guidance Characterization,

Survey, and Determination of Radiological Criteria, Final Report - September 2003 6-7 ZionSolutions Technical Support Document 14-019, Radionuclides of Concern for Soil and Basement Fill Model Source Terms 6-8 ZionSolutions Technical Support Document 10-002, Revision 1, Technical Basis for Radiological Limits for Structure/Building Open Air Demolition 6-9 ZionSolutions Technical Support Document 11-001, Revision 1, Potential Radionuclides of Concern during the Decommissioning of Zion Station 6-10 Pacific Northwest Laboratory, NUREG/CR-3474, Long-Lived Activation Products in Reactor Materials, Pacific Northwest Laboratory - 1984 6-11 Pacific Northwest Laboratory, NUREG/CR-4289, Residual Radionuclide Concentration Within and Around Commercial Nuclear Power Plants; Origin, Distribution, Inventory, and Decommissioning Assessment - 1985 6-12 Westinghouse Idaho Nuclear Company, Inc., WINCO-1191, Radionuclides in United States Commercial Nuclear Power Reactors - 1994 6-13 International Commission on Radiological Protection, ICRP Publication 38, Radiological Transformations - Energy and Intensity of Emissions - 1983 6-14 ZionSolutions Technical Support Document 14-010, Revision 6, RESRAD Dose Modeling for Basement Fill Model and Soil DCGL and Calculation of Basement Fill Model Dose Factors and DCGLs 6-15 The City of Zion, Official Zoning Map City of Zion - March 2011 6-16 United States Department of Agriculture, Custom Soil Resources Report Lake County Illinois - August 2013 6-17 Pacific Northwest Laboratory, NUREG/CR-5512, Volume 1, Residual Radioactive Contamination from Decommissioning - October 1992 6-18 ZionSolutions TSD 14-009, Revision 3, Brookhaven National Laboratory Report (BNL),

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-72 Evaluation of Maximum Radionuclide Groundwater Concentrations for Basement Fill Model, Zion Station Restoration Project 6-19 ZionSolutions Technical Support Document 14-032, Revision 0, Conestoga Rovers &

Associates Report, Simulation of the Post-Demoltion Saturation of Foundation Fill Using a Foundation Water Flow Model 6-20 ZionSolutions Technical Support Document 14-006, Revision 5, Conestoga Rovers &

Associates (CRA) Report, Evaluation of Hydrological Parameters in Support of Dose Modeling for the Zion Restoration Project 6-21 ZionSolutions Technical Support Document 14-004, Revision 1, Brookhaven National Laboratory (BNL), Recommended Values for the Distribution Coefficient (Kd) to be used in Dose Assessments for Decommissioning the Zion Nuclear Power Plant 6-22 ZionSolutions Technical Support Document 14-017, Revision 0, Brookhaven National Laboratory (BNL), Sorption (Kd) Measurements on Cinder Block and Grout in Support of Dose Assessments for Zion Nuclear Station Decommissioning 6-23 ZionSolutions Technical Support Document 14-020, Revision 0, Brookhaven National Laboratory (BNL), Sorption (Kd) measurements in Support of Dose Assessments for Zion Nuclear Station Decommissioning 6-24 Argonne National Laboratory, NUREG/CR-6697 Development of Probabilistic RESRAD 6.0 and RESRAD-BUILD 3.0 Computer Codes - December 2000 6-25 Sandia National Laboratory, NUREG/CR-5512, Volume 3, Residual Radioactive Contamination From Decommissioning Parameter Analysis - October 1999 6-26 Environmental Protection Agency, Federal Guidance Report No. 11, Limiting Values of Radionuclide Intake and Air Concentration and Dose Conversion Factors for Inhalation, Submersion and Ingestion - September 1988 6-27 Environmental Protection Agency, Federal Guidance Report No. 12, External Exposure to Radionuclides in Air, Water and Soil - September 1993 6-28 ZionSolutions Technical Support Document 14-021 Revision 1, Basement Fill Model (BFM) Drilling Spoils and Alternate Exposure Scenarios 6-29 U.S. Nuclear Regulatory Commission NUREG-1575, Revision 1, Multi-Agency Radiation Survey and Site Investigation Manual (MARSSIM) - August 2000 6-30 ZionSolutions Technical Support Document 14-011, Revision 0, Soil Area Factors 6-31 ZionSolutions TSD 17-004, Revision 3, "Operational Derived Concentration Guideline Levels for Final Status Surveys"

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-73 Figure 6-1 Zion Nuclear Power Station Geographical Location

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-74 Figure 6-2 Zion Nuclear Power Station Owner Controlled Area

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-75 Figure 6-3 Zion Nuclear Power Station Security Restricted Area

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-76 Figure 6-4 Backfilled Basement and Structures to Remain Below 588 Elevation

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-77 Figure 6-5 Cross Section A-A of Basements/Structures Below

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-78 Figure 6-6 Cross Section B-B of Basements/Structures Below 588 Elevation to Remain at License Termination

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-79 Figure 6-7 Cross Section C-C of Basements/Structures Below 588 Elevation to Remain at License Termination

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-80 Figure 6-8 Cross Section D-D of Basements/Structures Below 588

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-81 Figure 6-9 Visualization of BFM Conceptual Model

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-82 Figure 6-10 RESRAD Parameter Selection Flow Chart

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-83 ATTACHMENT 1 RESRAD Input Parameters for ZSRP BFM Uncertainty Analysis

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-84 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Soil Concentrations Basic radiation dose limit (mrem/y) 3 D

25 10 CFR 20.1402 NR NR NR NR Initial principal radionuclide (pCi/g)

P 2

D 1

Unit Value NR NR NR NR Distribution coefficients (contaminated, unsaturated, and saturated zones) (cm3/g)

Co-60 P

1 D

223 TSD 14-004 5.46 2.53 0.001 0.999 235 Cs-134 P

1 D

45 TSD 14-004 6.1 2.33 0.001 0.999 446 Cs-137 P

1 D

45 TSD 14-004 6.1 2.33 0.001 0.999 446 Eu-152 P

1 D

95 TSD 14-004 6.72 3.22 0.001 0.999 825 Eu-154 P

1 D

95 TSD 14-004 6.72 3.22 0.001 0.999 825 Gd-152 (daughter for Eu-152)

P 1

D 825 Median Value NUREG/CR-6697, Att. C 6.72 3.22 0.001 0.999 825 H-3 P

1 D

0 TSD 14-004

-2.81 0.5 0.001 0.999 0.06 Nd-144 (daughter for Eu-152)

P 1

D 158 RESRADv.7.0 Default Neodymium (Nd) not listed in NUREG/CR-6697 NA NA NA NA NA Ni-63 P

1 D

62 TSD 14-004 6.05 1.46 0.001 0.999 424 Sm-148 (daughter Eu-152)

P 1

D 825 Median Value NUREG/CR-6697, Att. C 6.72 3.22 0.001 0.999 825 Sr-90 P

1 D

2.3 TSD 14-004 3.45 2.12 0.001 0.999 32 Initial concentration of radionuclides present in groundwater (pCi/l)

P 3

D 0

No existing groundwater contamination NR NR NR NR Calculation Times Time since placement of material (y) P 3

D 1

For user convenience:

Allows use of t=0 in dose and concentration output reports to calculate unitized Exposure Factors NR NR NR NR Time for calculations (y)

P 3

D 0, 1, 3, 10, 30, 100, 300, 1000 RESRAD Default NR NR NR NR Contaminated Zone Area of contaminated zone (m2)

P 2

D 64,500 Area of the Security Protected Area on Zion Site NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-85 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Thickness of contaminated zone (m) P 2

D 11.2 Contaminated Zone is the Basement fill depth where mixing occurs. Depth of fill mixing zone depends on Basement floor elevation.

11.2 m is used as nominal value based on difference between elevations of the water table (579) and Auxiliary Basement floor (542) which equals 11.2m.

Note: this parameter has no effect on the calculated values for unitized Exposure Factors.

NR NR NR NR Length parallel to aquifer flow (m)

P 2

D 287 Diameter of 64,500 m2 contaminated area.

Note: not applicable to Basement Fill Model because Mass Balance groundwater model used.

NR NR NR NR Does the initial contamination penetrate the water table?

NA NA NA Yes 100% of the contamination assumed to be in the basement fill water mixing zone NA NA NA NA Contaminated fraction below water table Pe 3e D

1 100% of the contamination assumed to be in the basement fill water mixing zone NR NR NR NR Cover and Contaminated Zone Hydrological Data Cover depth (m)

P 2

D 3.6m Difference between ground level elevation at 591 (179.6m) and equilibrium water level in basements at 579 (176m)

NR NR NR NR NA Density of cover material P

2 D

1.8 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.5.

NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-86 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Cover erosion rate P,B 2

D Continuous Logarithmic NUREG/CR-6697 Att. C 5E-08 0,0007 0,005

.2 0.0015 Density of contaminated zone (g/cm3)

P 1

S Truncated Normal NUREG/CR-6697 Att. C Fill to be comprised of undetermined combination of clean concrete and native sand. NUREG/CR-6697 distribution used as placeholder - parameter has no effect on calculation of unitized Exposure Factors 1.52 0.23 0.001 0.999 1.52 Contaminated zone erosion rate (m/y)

P,B 2

S Continuous Logarithmic NUREG/CR-6697 Att. C 5E-08 0.0007 0,005 0.2 0.0015 Contaminated zone total porosity P

2 S

Truncated Normal NUREG/CR-6697 Att. C Fill to be comprised of undetermined combination of clean concrete and native sand. NUREG/CR-6697 distribution used as placeholder - parameter has no effect on calculation of unitized Exposure Factors 0.425 0.0867 0.001 0.999 0.42 Contaminated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Contaminated zone hydraulic conductivity (m/y)

P 2

S Loguniform Site-specific distribution from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Contaminated zone b parameter P

2 S

Bounded Lognormal - N NUREG/CR-6697, Att. C Fill to be comprised of undetermined combination of clean concrete and native sand. NUREG/CR-6697 distribution used as placeholder - parameter has no effect on calculation of unitized Exposure Factors 1.06 0.66 0.5 30 2.89 Humidity in air (g/m3)

P 3

D 7.2 Median NUREG/CR-6697 Att. C 1.98 0.334 0.001 0.999 7.2 Evapotranspiration coefficient P

2 S

Uniform NUREG/CR-6697 Att. C 0.5 0.75 NR NR 0.625 Average annual wind speed (m/s)

P 2

S Bounded Lognormal n NUREG/CR-6697 Att. C 1.445 0.2419 1.4 13 4.2

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-87 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Precipitation (m/y)

P 2

D 0.83 Site-specific value from Reference 6-21, Table 5.12 NR NR NR NR Irrigation (m/y)

B 3

D 0.19 NUREG-5512, Vol. 3, Table 6-18 (Illinois Average)

Converted 0.52 L/m2/d to m/y.

NR NR NR NR Irrigation mode B

3 D

Overhead Overhead irrigation is common practice in U. S.

NR NR NR NR Runoff coefficient P

2 S

Uniform NUREG/CR-6697 Att. C 0.1 0.8 NR NR 0.45 Watershed area for nearby stream or pond (m2)

P 3

D 1.0E+06 RESRAD Default NR NR NR NR Accuracy for water/soil computations 3

D 1.00E-03 RESRAD Default NR NR NR NR Saturated Zone Hydrological Data Density of saturated zone (g/cm3)

P 1

S Truncated Normal NUREG 6697 distribution for site soil type - sand 1.51 0.16 0.001 0.999 1.51 Saturated zone total porosity P

1 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.43 0.06 0.001 0.999 0.43 Saturated zone effective porosity P

1 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.383 0.0610 0.001 0.999 0.383 Saturated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Saturated zone hydraulic conductivity (m/y)

P 1

S Loguniform Site-specific distribution from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Saturated zone hydraulic gradient P

2 S

Bounded Lognormal - N NUREG/CR-6697 Att. C

-5.11 1.77 0.00007 0.5 0.006 Saturated zone b parameter P

2 D

NA saturated zone b not active because water table drop rate =0 NUREG/CR-6697 NR NR NR NR NR Water table drop rate (m/y)

P 3

D 0

Basement fill water assumed to supply well with no water table drop.

NR NR NR NR Well pump intake depth (m below water table)

P 2

S Triangular NUREG/CR-6697 Att. C 6

10 30 10 Model: Non-dispersion (ND) or Mass-Balance (MB)

P 3

D MB MB model most applicable to assumption that well located in center of basement fill.

NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-88 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Well pumping rate (m3/y)

B,P 2

D 2250 Calculated according to method described in NUREG/CR-6697, Att. C section 3.10 using Illinois average irrigation rate and NUREG/CR-5512 Vol. 3 livestock water consumption rate. Calculation provided at end of this table as Footnote

1.

NR NR NR NR NR Unsaturated Zone Hydrological Data Number of unsaturated zone strata P

NA NA 0

No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone thickness (m)

P NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone soil density (g/cm3)

P NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone total porosity P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone effective porosity P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone field capacity P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone hydraulic conductivity (m/y)

P NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone soil-specific b parameter P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Occupancy Inhalation rate (m3/y)

M,B 3

D 8400 NUREG/CR-5512, Vol. 3 Table 6.29

(= 23m3/d x 365d)

NR NR NR NR Mass loading for inhalation (g/m3)

P,B 2

S Continuous Linear NUREG/CR-6697, Att. C See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 2.35E-05 Exposure duration B

3 D

30 RESRAD Users Manual (Parameter not used in dose calculation)

NR NR NR NR Indoor dust filtration factor P,B 2

S Uniform NUREG/CR-6697, Att. C 0.15 0.95 0.55 Shielding factor, external gamma P

2 S

Bounded Lognormal - N NUREG/CR-6697, Att. C

-1.3 0.59 0.044 1

0.27

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-89 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Fraction of time spent indoors B

3 D

0.649 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Fraction of time spent outdoors (on site)

B 3

D 0.124 NUREG/CR-5512, Vol. 3 Table 6.87 (outdoors +

gardening)

NR NR NR NR Shape factor flag, external gamma P

3 D

Circular Circular contaminated zone assumed for modeling purposes NR NR NR NR Ingestion, Dietary Fruits, non-leafy vegetables, grain consumption (kg/y)

M,B 2

D 112 NUREG/CR-5512, Vol. 3 Table 6.87 (other vegetables + fruits + grain)

NR NR NR NR Leafy vegetable consumption (kg/y) M,B 3

D 21.4 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk consumption (L/y)

M,B 2

D 233 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry consumption (kg/y) M,B 3

D 65.1 NUREG/CR5512, Vol. 3 Table 6.87 (beef + poultry)

NR NR NR NR Fish consumption (kg/y)

M,B 3

D 20.6 NUREG/CR-5512, Vol. 3 Table 6.87 Note: Aquatic Pathway inactive in BFM NR NR NR NR Other seafood consumption (kg/y)

M,B 3

D 0.9 RESRAD Users Manual Table D.2 Note: Aquatic Pathway inactive in BFM NR NR NR NR Soil ingestion rate (g/y)

M,B 2

D 18.3 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Drinking water intake (L/y)

M,B 2

D 478 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Contamination fraction of drinking water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of household water (if used)

B,P 3

NA Contamination fraction of livestock water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of irrigation water B,P 3

D 1

All water assumed contaminated NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-90 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Contamination fraction of aquatic food B,P 2

NA NA Assumption that pond is constructed that intercepts contaminated water not credible at Zion site NR NR NR NR Contamination fraction of plant food B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Contamination fraction of meat B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Contamination fraction of milk B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Ingestion, Non-Dietary Livestock fodder intake for meat (kg/day)

M 3

D 28.3 NUREG/CR5512, Vol. 3 Table 6.87 (forage, grain and hay for beef cattle +

poultry + layer hen)

NR NR NR NR Livestock fodder intake for milk (kg/day)

M 3

D 65.2 NUREG/CR5512, Vol. 3 Table 6.87 (forage + grain +

hay)

NR NR NR NR Livestock water intake for meat (L/day)

M 3

D 50.6 NUREG/CR5512, Vol. 3 Table 6.87 (beef cattle +

poultry + layer hen)

NR NR NR NR Livestock water intake for milk (L/day)

M 3

D 60 NUREG/CR5512, Vol. 3 Table 6.87 NR NR NR NR Livestock soil intake (kg/day)

M 3

D 0.5 RESRAD Users Manual, Appendix L NR NR NR NR Mass loading for foliar deposition (g/m3)

P 3

D 4.00E-04 NUREG/CR-5512, Vol. 3 Table 6.87, gardening NR NR NR NR Depth of soil mixing layer (m)

P 2

S Triangular NUREG/CR-6697, Att. C 0

0.15 0.6 0.23 Depth of roots (m)

P 1

S Uniform NUREG/CR-6697, Att. C 0.3 4.0 2.15 Drinking water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Household water fraction from ground water (if used)

B,P 3

NA Not used Livestock water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Irrigation fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Wet weight crop yield for Non-Leafy (kg/m2)

P 2

S Truncated Lognormal - N NUREG/CR-6697, Att. C 0.56 0.48 0.001 0.999 1.75

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-91 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Wet weight crop yield for Leafy (kg/m2)

P 3

D 2.89 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet weight crop yield for Fodder (kg/m2)

P 3

D 1.91 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Non-Leafy (y)

P 3

D 0.25 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Leafy (y)

P 3

D 0.12 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Fodder (y)

P 3

D 0.082 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Non-Leafy P

3 D

0.1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Leafy P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Fodder P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Weathering Removal Constant for Vegetation (1/y)

P 2

S Triangular NUREG/CR-6697, Att. C 5.1 18 84 33 Wet Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet Foliar Interception Fraction for Leafy P

2 S

Triangular NUREG/CR-6697, Att. C 0.06 0.67 0.95 0.58 Wet Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Storage times of contaminated foodstuffs (days):

Fruits, non-leafy vegetables, and grain B

3 D

14 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Leafy vegetables B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 (holdup period for beef = 20d and poultry

=1 day. Lowest value used)

NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-92 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Fish B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive in BFM NR NR NR NR Crustacea and mollusks B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive in BFM NR NR NR NR Well water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Surface water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Livestock fodder B

3 D

45 RESRAD Users Manual Table D.6 NR NR NR NR Special Radionuclides (C-14)

C-12 concentration in water (g/cm3) P 3

NA NA NA NR NR NR NR C-12 concentration in contaminated soil (g/g)

P 3

NA NA NA NR NR NR NR Fraction of vegetation carbon from soil P

3 NA NA NA NR NR NR NR Fraction of vegetation carbon from air P

3 NA NA NA NR NR NR NR C-14 evasion layer thickness in soil (m)

P 2

NA NA NA NR NR NR NR C-14 evasion flux rate from soil (1/sec)

P 3

NA NA NA NR NR NR NR C-12 evasion flux rate from soil (1/sec)

P 3

NA NA NA NR NR NR NR Fraction of grain in beef cattle feed B 3

NA NA NA NR NR NR NR Fraction of grain in milk cow feed B

3 NA NA NA NR NR NR NR Dose Conversion Factors (Inhalation mrem/pCi)

Co-60 M

3 D

2.19E-04 FGR11 NR NR NR NR Cs-134 M

3 D

4.62E-05 FGR11 NR NR NR NR Cs-137 M

3 D

3.19E-05 FGR11 NR NR NR NR Eu-152 M

3 D

2.21E-04 FGR11 NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-93 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Eu-154 M

3 D

2.86E-04 FGR11 NR NR NR NR Gd-152 M

3 D

2.43E-01 FGR11 NR NR NR NR H-3 M

3 D

6.40E-08 FGR11 NR NR NR NR Ni-63 M

3 D

6.29E-06 FGR11 NR NR NR NR Nd-144f M

3 D

7.04E-02 ICRP60 NR NR NR NR Sm-148f M

3 D

7.34E-02 ICRP60 NR NR NR NR Sr-90 M

3 D

1.30E-03 FGR11 NR NR NR NR Dose Conversion Factors (Ingestion mrem/pCi)

Co-60 M

3 D

2.69E-05 FGR11 NR NR NR NR Cs-134 M

3 D

7.33E-05 FGR11 NR NR NR NR Cs-137 M

3 D

5.00E-05 FGR11 NR NR NR NR Eu-152 M

3 D

6.48E-06 FGR11 NR NR NR NR Eu-154 M

3 D

9.55E-06 FGR11 NR NR NR NR Gd-152 M

3 D

1.61E-04 FGR11 NR NR NR NR H-3 M

3 D

6.40E-08 FGR11 NR NR NR NR Ni-63 M

3 D

5.77E-07 FGR11 NR NR NR NR Nd-144f M

3 D

1.51E-04 ICRP60 NR NR NR NR Sm-148f M

3 D

1.58E-04 ICRP60 NR NR NR NR Sr-90 M

3 D

1.42E-04 FGR11 NR NR NR NR Plant Transfer Factors (pCi/g plant)/(pCi/g soil)

Co-60 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-2.53 0.9 7.9E-02 Cs-134 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Cs-137 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-94 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Eu-152 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Eu-154 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Gd-152 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 H-3 P

1 S

Lognormal - N NUREG/CR-6697, Att. C 1.57 1.1 4.8E+00 Nd-144 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Ni-63 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-3.00 0.9 5.0E-02 Sm-148 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Sr-90 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-1.20 1.0 3.0E-01 Meat Transfer Factors (pCi/kg)/(pCi/d)

Co-60 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.51 1.0 3.0E-02 Cs-134 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Cs-137 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Eu-152 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 Eu-154 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 Gd-152 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 H-3 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.42 1.0 1.2E-02 Nd-144 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 Ni-63 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-5.30 0.9 5.0E-03 Sm-148 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Sr-90 P

2 S

Lognormal-N NUREG/CR-6697, Att. C

-4.61 0.4 1.0E-02 Milk Transfer Factors (pCi/L)/(pCi/d)

Co-60 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 0.7 2.0E-03

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-95 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Cs-134 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Cs-137 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Eu-152 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Eu-154 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Gd-152 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 H-3 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.6 0.9 1.0E-02 Nd-144 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Ni-63 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.91 0.7 2.0E-02 Sr-90 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 0.5 2.0E-03 Sm-148 P

2 S

Lognormal-N NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Bioaccumulation Factors for Fish ((pCi/kg)/(pCi/L))

Co-60 P

2 NA Inactive NUREG/CR-6697, Att. C 5.7 1.1 3.0E+02 Cs-134 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Cs-137 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Eu-152 P

2 NA Inactive NUREG/CR-6697, Att. C 3.9 1.1 4.9E+01 Eu-154 P

2 NA Inactive NUREG/CR-6697, Att. C 3.9 1.1 4.9E+01 Gd-152 P

2 NA Inactive NUREG/CR-6697, Att. C 3.2 1.1 2.5E+01 H-3 P

2 NA Inactive NUREG/CR-6697, Att. C 0

0.1 1.0E+00 Nd-144 P

2 NA Inactive NUREG/CR-6697, Att. C 4.6 1.1 9.9E-01 Ni-63 P

2 NA Inactive NUREG/CR-6697, Att. C 4.6 1.1 9.9E+01 Sm-148 P

2 NA Inactive NUREG/CR-6697, Att. C 3.2 1.1 2.5E+01 Sr-90 P

2 NA Inactive NUREG/CR-6697, Att. C 4.1 1.1 6.0E+01 Bioaccumulation Factors for Crustacea/ Mollusks ((pCi/kg)/(pCi/L))

Co-60 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-134 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-137 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR

RESRAD Input Parameters for ZSRP BFM Sensitivity Analysis 6-96 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Eu-152 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Eu-154 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Gd-152 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR H-3 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Nd-144 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Ni-63 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Sm-148 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Sr-90 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Graphics Parameters Number of points 32 RESRAD Default NR NR NR NR Spacing log RESRAD Default NR NR NR NR Time integration parameters Maximum number of points for dose 17 RESRAD Default NR NR NR NR Notes: a P = physical, B = behavioral, M = metabolic; (see NUREG/CR-6697, Attachment B, Table 4.)

b 1 = high-priority parameter, 2 = medium-priority parameter, 3 = low-priority parameter (see NUREG/CR-6697, Attachment B, Table 4.1) c D = deterministic, S = stochastic d Distributions Statistical Parameters:

Lognormal-n: 1= mean, 2 = standard deviation Bounded lognormal-n: 1= mean, 2 = standard deviation, 3 = minimum, 4 = maximum Truncated lognormal-n: 1= mean, 2 = standard deviation, 3 = lower quantile, 4 = upper quantile Bounded normal: 1 = mean, 2 = standard deviation, 3 = minimum, 4 = maximum Beta: 1 = minimum, 2 = maximum, 3 = P-value, 4 = Q-value Triangular: 1 = minimum, 2 = mode, 3 = maximum Uniform: 1 = minimum, 2 = maximum

6-97 Footnote 1 Basement Fill Model: RESRAD Well Pumping Rate Parameter Calculation Input Value Reference Water Table Elevation 579.00 ft 176.0 m Reference 6-21, Table 5.1 Ground Surface Elevation 591.00 ft 179.7 m Reference 6-21, Table 5.2 Auxiliary Bldg. Floor Surface Area 27484.42 ft2 2540 m2 Reference 6-7, TSD 14-019 Auxiliary Bldg. Floor Elevation 542.00 ft 164.8 m Reference 6-7, TSD 14-019 Demolition Below Grade 3.00 ft 0.9 m Project Plans Post-Dem Wall Height Aux Bldg 46.00 ft 14.0 m Calculation Water Table Height above Aux Floor 37.00 ft 11.2 m Calculation Ground Surface to Water Table 12.00 ft 3.648 m Calculation Cont Zone total porosity 0.35

[1]

Precipitation 0.83 m/y

[1]

well pump rate 2250 m3/y NUREG-6697, Table 3.10-1 method inputs 0.52 L/m2/d irrigation rate NUREG-5512, Volume 3, Table 6-18 (Illinios Average) 0.19 m3/m2/yr irrigation rate conversion 10000.00 m2 contaminated area (nominal 2 cattle at ~1 per acre + 2000 m2 garden) [1]

Calculation 328.70 m3 domestic use Reference 6-25, Table 3.10-1 50.6 and 60 L/d (1 dairy 1 meat) 40.37 m3/y livestock Reference 6-25, Table 3.10-1 189.80 m3/y vegetable garden irrigation Reference 6-25, Table 3.10-1 1689.22 m3/y pasture irrigation Reference 6-25, Table 3.10-1 1.64 m3/y drinking water Reference 6-25, Table 3.10-1 Conversion Factors m/ft 0.304 m2/ft2 0.09 Ref [1]:

Pastures for Profit: A guide to Rotational Grazing (A3529),

University of Wisconson Extension, 2002.

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-98 ATTACHMENT 2 RESRAD Input Parameters for ZSRP BFM

6-99 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Soil Concentrations Basic radiation dose limit (mrem/y)

NA 3

D 25 10 CFR 20.1402 NR NR NR NR Initial principal radionuclide (pCi/g)

P 2

D 1

Unit Value NR NR NR NR Distribution coefficients (contaminated, unsaturated, and saturated zones) (cm3/g)

Co-60 P

1 D

223 TSD 14-004 5.46 2.53 0.001 0.999 235 Cs-134 P

1 D

45 TSD 14-004 6.1 2.33 0.001 0.999 446 Cs-137 P

1 D

45 TSD 14-004 6.1 2.33 0.001 0.999 446 Eu-152 P

1 D

95 TSD 14-004 6.72 3.22 0.001 0.999 825 Eu-154 P

1 D

95 TSD 14-004 6.72 3.22 0.001 0.999 825 Gd-152 (daughter for Eu-152)

P 1

D 825 Median Value NUREG/CR-6697, Att. C 6.72 3.22 0.001 0.999 825 H-3 P

1 D

0 TSD 14-004

-2.81 0.5 0.001 0.999 0.06 Nd-144 (daughter for Eu-152)

P 1

D 158 RESRADv.7.0 Default Nd not listed in NUREG/CR-6697 NA NA NA NA NA Ni-63 P

1 D

62 TSD 14-004 6.05 1.46 0.001 0.999 424 Sm-148 (daughter Eu-152)

P 1

D 825 Median Value NUREG/CR-6697, Att. C 6.72 3.22 0.001 0.999 825 Sr-90 P

1 D

2.3 TSD 14-004 3.45 2.12 0.001 0.999 32 Initial concentration of radionuclides present in groundwater (pCi/l)

P 3

D 0

No existing groundwater contamination NR NR NR NR Calculation Times Time since placement of material (y) P 3

D 1

For user convenience:

Allows use of t=0 in dose and concentration output reports to calculate unitized Exposure Factors NR NR NR NR Time for calculations (y)

P 3

D 0, 1, 3, 10, 30, 100, 300, 1000 RESRAD Default NR NR NR NR Contaminated Zone Area of contaminated zone (m2)

P 2

D 64,500 Area of the Radiological Protected Area on Zion Site NR NR NR NR

6-100 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Thickness of contaminated zone (m) P 2

D 11.2 Contaminated Zone is the Basement fill depth where mixing occurs. Depth of fill mixing zone depends on Basement floor elevation.

11.2 m is used as nominal value based on difference between elevations of the water table (579) and Auxiliary Basement floor (542) which equals 11.2m.

Note: this parameter has no effect on the calculated values for unitized Exposure Factors.

NR NR NR NR Length parallel to aquifer flow (m)

P 2

D 287 Diameter of 64,500 m2 contaminated area.

Note: not applicable to Basement Fill Model because Mass Balance groundwater model used.

NR NR NR NR Does the initial contamination penetrate the water table?

NA NA NA Yes 100% of the contamination assumed to be in the basement fill water mixing zone NA NA NA NA Contaminated fraction below water table Pe 3e D

1 100% of the contamination assumed to be in the basement fill water mixing zone NR NR NR NR Cover and Contaminated Zone Hydrological Data Cover depth (m)

P 2

D 3.6m Difference between ground level elevation at 591 (179.6m) and equilibrium water level in basements at 579 (176m)

NR NR NR NR NA Density of cover (g/cm3)

P 1

D 1.8 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.5.

1.52 0.23 0.001 0.999 1.52 Cover erosion rate (m/y)

P,B 2

D 0.0015 Median NUREG/CR-6697 Att. C 5E-08 0.0007 0,005 0.2 0.0015

6-101 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Density of contaminated zone (g/cm3)

P 1

D 1.8 Density identified as sensitive and positively correlated. The 75th Percentile of the NUREG/CR-6697 Att. C distribution is 1.67 g/cm3.

However, the site-specific value for sand density is 1.8 g/cm3.

Fill to be comprised of undetermined combination of clean concrete and native sand therefore higher value for site-specific sand used.

1.52 0.23 0.001 0.999 1.52 Contaminated zone erosion rate (m/y)

P,B 2

D 0.0015 Median NUREG/CR-6697 Att. C 5E-08 0.0007 0,005 0.2 0.0015 Contaminated zone total porosity P

2 D

0.37 25th Percentile NUREG/CR-6697 Att. C.

0.425 0.0867 0.001 0.999 0.42 Contaminated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Contaminated zone hydraulic conductivity (m/y)

P 2

D 2880 Site-specific value from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Contaminated zone b parameter P

2 D

2.89 Median NUREG/CR-6697, Att. C 1.06 0.66 0.5 30 2.89 Humidity in air (g/m3)

P 3

D 7.2 Median NUREG/CR-6697 Att. C 1.98 0.334 0.001 0.999 7.2 Evapotranspiration coefficient P

2 D

0.625 Median NUREG/CR-6697 Att. C 0.5 0.75 NR NR 0.625 Average annual wind speed (m/s)

P 2

D 4.2 Median NUREG/CR-6697 Att. C 1.445 0.2419 1.4 13 4.2 Precipitation (m/y)

P 2

D 0.83 Site-specific value from Reference 6-21, Table 5.12 NR NR NR NR Irrigation (m/y)

B 3

D 0.19 NUREG-5512, Vol. 3, Table 6-18 (Illinois Average).

Converted 0.52 L/m2/d to m/y.

NR NR NR NR Irrigation mode B

3 D

Overhead Overhead irrigation is common practice in U. S.

NR NR NR NR Runoff coefficient P

2 D

0.2 Site-specific value from Reference 6-21, Section 5.10 0.1 0.8 NR NR 0.45 Watershed area for nearby stream or pond (m2)

P 3

D 1.0E+06 RESRAD Default NR NR NR NR

6-102 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Accuracy for water/soil computations 3

D 1.00E-03 RESRAD Default NR NR NR NR Saturated Zone Hydrological Data Density of saturated zone (g/cm3)

P 1

D 1.8 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.5.

1.51 0.16 0.001 0.999 1.51 Saturated zone total porosity P

1 D

0.35 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.6 0.43 0.06 0.001 0.999 0.43 Saturated zone effective porosity P

1 D

0.29 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.7 0.383 0.0610 0.001 0.999 0.383 Saturated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Saturated zone hydraulic conductivity (m/y)

P 1

D 1695 25th percentile Site-specific distribution from Reference 6-21, Table 5.9.

786 17000 NA NA 3649 Saturated zone hydraulic gradient P

2 D

0.0018 25th Percentile NUREG/CR-6697 Att. C distribution Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.10 is greater at 0.0039 but lower value used

-0.511 1.77 0.00007 0.5 0.006 Saturated zone b parameter P

2 D

NA saturated zone b not active in RESRAD because water table drop rate =0 RESRAD User Manual NR NR NR NR NR Water table drop rate (m/y)

P 3

D 0

Basement fill water assumed to fully supply well.

NR NR NR NR

6-103 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Well pump intake depth (m below water table)

P 2

D 5.6 Basement depths vary.

5.2m selected as nominal value based on mid-point of 11.2m contaminated zone for Auxiliary Basement.

Note: this parameter has no effect on the calculated values for unitized Exposure Factors.

6 10 30 NA 10 Model: Non-dispersion (ND) or Mass-Balance (MB)

P 3

D MB MB model most applicable to assumption that well located in center of basement fill.

NR NR NR NR Well pumping rate (m3/y)

B,P 2

D 2250 Calculated according to method described in NUREG/CR-6697, Att. C Section 3.10 using Illinois specific irrigation rate and NUREG/CR-5512 vol. 3 livestock water consumption rate.

NR NR NR NR NR Unsaturated Zone Hydrological Data Number of unsaturated zone strata P

NA NA 0

No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone thickness (m)

P NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone soil density (g/cm3)

P NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone total porosity P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone effective porosity P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone field capacity P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone hydraulic conductivity (m/y)

P NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Unsat. zone soil-specific b parameter P

NA NA NA No unsaturated zone in Basement Fill Model NA NA NA NA Occupancy

6-104 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Inhalation rate (m3/y)

M,B 3

D 8400 NUREG/CR-5512, Vol. 3 Table 6.29

(= 23 m3/d x 365 d/y)

NR NR NR NR Mass loading for inhalation (g/m3)

P,B 2

D 2.35E-05 Median NUREG/CR-6697, Att. C See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 2.35E-05 Exposure duration B

3 D

30 RESRAD Users Manual (Parameter not used in dose calculation)

NR NR NR NR Indoor dust filtration factor P,B 2

D 0.55 Median NUREG/CR-6697, Att. C 0.15 0.95 0.55 Shielding factor, external gamma P

2 D

0.27 Median NUREG/CR-6697, Att. C

-1.3 0.59 0.044 1

0.27 Fraction of time spent indoors B

3 D

0.649 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Fraction of time spent outdoors (on site)

B 3

D 0.124 NUREG/CR-5512, Vol. 3 Table 6.87 (outdoors +

gardening)

NR NR NR NR Shape factor flag, external gamma P

3 D

Circular Circular contaminated zone assumed for modeling purposes NR NR NR NR Ingestion, Dietary Fruits, non-leafy vegetables, grain consumption (kg/y)

M,B 2

D 112 NUREG/CR-5512, Vol. 3 Table 6.87 (other vegetables + fruits + grain)

NR NR NR NR Leafy vegetable consumption (kg/y) M,B 3

D 21.4 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk consumption (L/y)

M,B 2

D 233 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry consumption (kg/y) M,B 3

D 65.1 NUREG/CR5512, Vol. 3 Table 6.87 (beef + poultry)

NR NR NR NR Fish consumption (kg/y)

M,B 3

D 20.6 NUREG/CR-5512, Vol. 3 Table 6.87 Note: Aquatic Pathway inactive in BFM NR NR NR NR

6-105 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Other seafood consumption (kg/y)

M,B 3

D 0.9 RESRAD Users Manual Table D.2 Note: Aquatic Pathway inactive in BFM NR NR NR NR Soil ingestion rate (g/y)

M,B 2

D 18.3 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Drinking water intake (L/y)

M,B 2

D 478 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Contamination fraction of drinking water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of household water (if used)

B,P 3

NA Contamination fraction of livestock water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of irrigation water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of aquatic food B,P 2

D NA Assumption that pond is constructed that intercepts contaminated water not credible at Zion site NR NR NR NR Contamination fraction of plant food B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Contamination fraction of meat B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Contamination fraction of milk B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Ingestion, Non-Dietary Livestock fodder intake for meat (kg/day)

M 3

D 28.3 NUREG/CR5512, Vol. 3 Table 6.87 (forage, grain and hay for beef cattle +

poultry + layer hen)

NR NR NR NR Livestock fodder intake for milk (kg/day)

M 3

D 65.2 NUREG/CR5512, Vol. 3 Table 6.87 (forage + grain +

hay)

NR NR NR NR Livestock water intake for meat (L/day)

M 3

D 50.6 NUREG/CR5512, Vol. 3 Table 6.87 (beef cattle +

poultry + layer hen)

NR NR NR NR Livestock water intake for milk (L/day)

M 3

D 60 NUREG/CR5512, Vol. 3 Table 6.87 NR NR NR NR Livestock soil intake (kg/day)

M 3

D 0.5 RESRAD Users Manual, Appendix L NR NR NR NR Mass loading for foliar deposition (g/m3)

P 3

D 4.00E-04 NUREG/CR-5512, Vol. 3 Table 6.87, gardening NR NR NR NR

6-106 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Depth of soil mixing layer (m)

P 2

D 0.23 Median NUREG/CR-6697, Att. C 0

0.15 0.6 0.23 Depth of roots (m)

P 1

D 3.1 75th Percentile NUREG/CR-6697, Att. C 0.3 4.0 2.15 Drinking water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Household water fraction from ground water (if used)

B,P 3

NA Livestock water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Irrigation fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Wet weight crop yield for Non-Leafy (kg/m2)

P 2

D 1.26 25th Percentile NUREG/CR-6697, Att. C 0.56 0.48 0.001 0.999 1.75 Wet weight crop yield for Leafy (kg/m2)

P 3

D 2.89 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet weight crop yield for Fodder (kg/m2)

P 3

D 1.91 NUREG/CR-5512, Vol. 3 Table 6.87 (maximum of forage, grain and hay)

NR NR NR NR Growing Season for Non-Leafy (y)

P 3

D 0.25 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Leafy (y)

P 3

D 0.12 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Fodder (y)

P 3

D 0.082 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Non-Leafy P

3 D

0.1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Leafy P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Fodder P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Weathering Removal Constant for Vegetation (1/y)

P 2

D 21.5 25th Percentile NUREG/CR-6697, Att. C 5.1 18 84 33 Wet Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet Foliar Interception Fraction for Leafy P

2 D

0.70 75th Percentile NUREG/CR-6697, Att. C 0.06 0.67 0.95 0.58 Wet Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR

6-107 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Dry Foliar Interception Fraction for Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Storage times of contaminated foodstuffs (days):

Fruits, non-leafy vegetables, and grain B

3 D

14 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Leafy vegetables B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 (holdup period for beef = 20d and poultry

=1 day. Lowest value used)

NR NR NR NR Fish B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive in BFM NR NR NR NR Crustacea and mollusks B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive in BFM NR NR NR NR Well water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Surface water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Livestock fodder B

3 D

45 RESRAD Users Manual Table D.6 NR NR NR NR Special Radionuclides (C-14)

C-12 concentration in water (g/cm3) P 3

D NA NA NR NR NR NR C-12 concentration in contaminated soil (g/g)

P 3

D NA NA NR NR NR NR Fraction of vegetation carbon from soil P

3 D

NA NA NR NR NR NR Fraction of vegetation carbon from air P

3 D

NA NA NR NR NR NR C-14 evasion layer thickness in soil (m)

P 2

D NA NA NR NR NR NR C-14 evasion flux rate from soil (1/sec)

P 3

D NA NA NR NR NR NR

6-108 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median C-12 evasion flux rate from soil (1/sec)

P 3

D NA NA NR NR NR NR Fraction of grain in beef cattle feed B 3

D NA NA NR NR NR NR Fraction of grain in milk cow feed B

3 D

NA NA NR NR NR NR Dose Conversion Factors (Inhalation mrem/pCi)

Co-60 M

3 D

2.19E-04 FGR11 NR NR NR NR Cs-134 M

3 D

4.62E-05 FGR11 NR NR NR NR Cs-137 M

3 D

3.19E-05 FGR11 NR NR NR NR Eu-152 M

3 D

2.21E-04 FGR11 NR NR NR NR Eu-154 M

3 D

2.86E-04 FGR11 NR NR NR NR Gd-152 M

3 D

2.43E-01 FGR11 NR NR NR NR H-3 M

3 D

6.40E-08 FGR11 NR NR NR NR Nd-144f M

3 D

7.04E-02 ICRP60 NR NR NR NR Ni-63 M

3 D

6.29E-06 FGR11 NR NR NR NR Sm-148f M

3 D

7.34E-02 ICRP60 NR NR NR NR Sr-90 M

3 D

1.30E-03 FGR11 NR NR NR NR Dose Conversion Factors (Ingestion mrem/pCi)

Co-60 M

3 D

2.69E-05 FGR11 NR NR NR NR Cs-134 M

3 D

7.33E-05 FGR11 NR NR NR NR Cs-137 M

3 D

5.00E-05 FGR11 NR NR NR NR Eu-152 M

3 D

6.48E-06 FGR11 NR NR NR NR Eu-154 M

3 D

9.55E-06 FGR11 NR NR NR NR Gd-152 M

3 D

1.61E-04 FGR11 NR NR NR NR H-3 M

3 D

6.40E-08 FGR11 NR NR NR NR

6-109 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Nd-144f M

3 D

1.51E-04 ICRP60 NR NR NR NR Ni-63 M

3 D

5.77E-07 FGR11 NR NR NR NR Sm-148f M

3 D

1.58E-04 ICRP60 NR NR NR NR Sr-90 M

3 D

1.42E-04 FGR11 NR NR NR NR Plant Transfer Factors (pCi/g plant)/(pCi/g soil)

Co-60 P

1 D

7.9E-02 Median NUREG/CR-6697, Att. C

-2.53 0.9 7.9E-02 Cs-134 P

1 D

4.0E-02 Median NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Cs-137 P

1 D

4.0E-02 Median NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Eu-152 P

1 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Eu-154 P

1 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Gd-152 P

1 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 H-3 P

1 D

4.8E+00 Median NUREG/CR-6697, Att. C 1.57 1.1 4.8E+00 Nd-144 P

1 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Ni-63 P

1 D

5.0E-02 Median NUREG/CR-6697, Att. C

-3.00 0.9 5.0E-02 Sm-148 P

1 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Sr-90 P

1 D

5.9E-01 75th Percentile NUREG/CR-6697, Att. C

-1.20 1.0 3.0E-01 Meat Transfer Factors (pCi/kg)/(pCi/d)

Co-60 P

2 D

0.058 75th Percentile NUREG/CR-6697, Att. C

-3.51 1.0 3.0E-02 Cs-134 P

2 D

0.065 75th Percentile NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Cs-137 P

2 D

0.065 75th Percentile NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Eu-152 P

2 D

0.004 75th Percentile NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 Eu-154 P

2 D

0.004 75th Percentile NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03

6-110 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Gd-152 P

2 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 H-3 P

2 D

0.012 Median NUREG/CR-6697, Att. C

-4.42 1.0 0.012 Nd-144 P

2 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.0 2.0E-03 Ni-63 P

2 D

0.0092 75th Percentile NUREG/CR-6697, Att. C

-5.30 0.9 5.0E-03 Sm-148 P

2 D

2.0E-03 Median NUREG/CR-6697, Att. C

-6.21 1.1 2.0E-03 Sr-90 P

2 D

0.013 75th Percentile NUREG/CR-6697, Att. C

-4.61 0.4 1.0E-02 Milk Transfer Factors (pCi/L)/(pCi/d)

Co-60 P

2 D

0.0032 75th Percentile NUREG/CR-6697, Att. C

-6.21 0.7 2.0E-03 Cs-134 P

2 D

1.4E-02 75th Percentile NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Cs-137 P

2 D

1.4E-02 75th Percentile NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Eu-152 P

2 D

6.0E-05 Median NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Eu-154 P

2 D

6.0E-05 Median NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Gd-152 P

2 D

6.0E-05 Median NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 H-3 P

2 D

0.010 Median NUREG/CR-6697, Att. C

-4.6 0.9 1.0E-02 Nd-144 P

2 D

6.0E-05 Median NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Ni-63 P

2 D

0.032 75th Percentile NUREG/CR-6697, Att. C

-3.91 0.7 2.0E-02 Sm-148 P

2 D

6.0E-05 Median NUREG/CR-6697, Att. C

-9.72 0.9 6.0E-05 Sr-90 P

2 D

0.0028 75th Percentile NUREG/CR-6697, Att. C

-6.21 0.5 2.0E-03 Bioaccumulation Factors for Fish ((pCi/kg)/(pCi/L))

Co-60 P

2 NA Inactive NUREG/CR-6697, Att. C 5.7 1.1 3.0E+02 Cs-134 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Cs-137 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03

6-111 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Eu-152 P

2 NA Inactive NUREG/CR-6697, Att. C 3.9 1.1 4.9E+01 Eu-154 P

2 NA Inactive NUREG/CR-6697, Att. C 3.9 1.1 4.9E+01 Gd-152 P

2 NA Inactive NUREG/CR-6697, Att. C 3.2 1.1 2.5E+01 H-3 P

2 NA Inactive NUREG/CR-6697, Att. C 0

0.1 1.0E+00 Nd-144 P

2 NA Inactive NUREG/CR-6697, Att. C 4.6 1.1 9.9E-01 Ni-63 P

2 NA Inactive NUREG/CR-6697, Att. C 4.6 1.1 1.0E+02 Sm-148 P

2 NA Inactive NUREG/CR-6697, Att. C 3.2 1.1 2.5E+01 Sr-90 P

2 NA Inactive NUREG/CR-6697, Att. C 4.1 1.1 6.0E+01 Bioaccumulation Factors for Crustacea/ Mollusks ((pCi/kg)/(pCi/L))

Co-60 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-134 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-137 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Eu-152 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Eu-154 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Gd-152 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR H-3 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Nd-144 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Ni-63 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Sm-148 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Sr-90 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Graphics Parameters Number of points 32 RESRAD Default NR NR NR NR

6-112 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Spacing log RESRAD Default NR NR NR NR Time integration parameters Maximum number of points for dose 17 RESRAD Default NR NR NR NR Notes:

a P = physical, B = behavioral, M = metabolic; (see NUREG/CR-6697, Attachment B, Table 4.)

b 1 = high-priority parameter, 2 = medium-priority parameter, 3 = low-priority parameter (see NUREG/CR-6697, Attachment B, Table 4.1) c D = deterministic, S = stochastic d Distributions Statistical Parameters:

Lognormal-n: 1= mean, 2 = standard deviation Bounded lognormal-n: 1= mean, 2 = standard deviation, 3 = minimum, 4 = maximum Truncated lognormal-n: 1= mean, 2 = standard deviation, 3 = lower quantile, 4 = upper quantile Bounded normal: 1 = mean, 2 = standard deviation, 3 = minimum, 4 = maximum Beta: 1 = minimum, 2 = maximum, 3 = P-value, 4 = Q-value Triangular: 1 = minimum, 2 = mode, 3 = maximum Uniform: 1 = minimum, 2 = maximum

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-113 ATTACHMENT 3 RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil Uncertainty Analysis

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-114 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Soil Concentrations Basic radiation dose limit (mrem/y) 3 D

25 10 CFR 20.1402 NR NR NR NR Initial principal radionuclide (pCi/g)

P 2

D 1

Unit Value NR NR NR NR Distribution coefficients (contaminated, unsaturated, and saturated zones) (cm3/g)

Co-60 P

1 D

1161 TSD 14-004 5.46 2.53 0.001 0.999 235 Cs-134 P

1 D

615 TSD 14-0042 6.1 2.33 0.001 0.999 446 Cs-137 P

1 D

615 TSD 14-004 6.1 2.33 0.001 0.999 446 Ni-63 P

1 D

62 TSD 14-004 6.05 1.46 0.001 0.999 424 Sr-90 P

1 D

2.3 TSD 14-004 3.45 2.12 0.001 0.999 32 Initial concentration of radionuclides present in groundwater (pCi/l)

P 3

D 0

No existing groundwater contamination NR NR NR NR Calculation Times Time since placement of material (y) P 3

D 0

RESRAD Default NR NR NR NR Time for calculations (y)

P 3

D 0, 1, 3, 10, 30, 100, 300, 1000 RESRAD Default NR NR NR NR Contaminated Zone Area of contaminated zone (m2)

P 2

D 64,500 Area of the Security Protected Area on Zion Site NR NR NR NR Thickness of contaminated zone (m) P 2

D 0.15 or 1 Surface soil depth 0.15 Subsurface soil depth 1 m NR NR NR NR Length parallel to aquifer flow (m)

P 2

D 287 Diameter of 64,500 m2 contaminated area.

NR NR NR NR Does the initial contamination penetrate the water table?

NA NA NA No No contamination in water table NA NA NA NA Contaminated fraction below water table Pe 3e D

0 No contamination in water table NR NR NR NR Cover and Contaminated Zone Hydrological Data Cover depth (m)

P 2

D 0

No Cover NR NR NR NR NA Density of cover (g/cm3)

P 1

NA NA No Cover NA NA NA NA NA Cover erosion rate (m/y)

P,B 2

NA Continuous Logarithmic NUREG/CR-6697 Att. C Table 3.8-1 5E-08 0.0007 0.005 0.2 0.0015

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-115 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Density of contaminated zone (g/cm3)

P 1

S Truncated Normal NUREG 6697 distribution for site soil type - sand 1.51 0.16 0.001 0.999 1.51 Contaminated zone erosion rate (m/y)

P,B 2

S Continuous Logarithmic NUREG/CR-6697 Att. C Table 3.8-1 5E-08 0.0007 0.005 0.2 0.0015 Contaminated zone total porosity P

2 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.43 0.06 0.001 0.999 0.43 Contaminated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Contaminated zone hydraulic conductivity (m/y)

P 2

S Loguniform Site-specific distribution from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Contaminated zone b parameter P

2 S

Truncated Lognormal - N NUREG 6697 distribution for site soil type - sand

-.0253 0.216 0.001 0.999 0.97 Humidity in air (g/m3)

P 3

D 7.2 Median NUREG/CR-6697 Att. C 1.98 0.334 0.001 0.999 7.2 Evapotranspiration coefficient P

2 S

Uniform NUREG/CR-6697 Att. C 0.5 0.75 NR NR 0.625 Average annual wind speed (m/s)

P 2

S Bounded Lognormal N NUREG/CR-6697 Att. C 1.445 0.2419 1.4 13 4.2 Precipitation (m/y)

P 2

D 0.83 Site-specific value from Reference 6-21, Table 5.12 NR NR NR NR Irrigation (m/y)

B 3

D 0.19 NUREG-5512, Vol. 3, Table 6-18 (Illinois Average)

Converted 0.52 L/m2/y to m/y NR NR NR NR 0.56 Irrigation mode B

3 D

Overhead Overhead irrigation is common practice in U. S.

NR NR NR NR Runoff coefficient P

2 S

Uniform NUREG/CR-6697 Att. C 0.1 0.8 NR NR 0.45 Watershed area for nearby stream or pond (m2)

P 3

D 1.0E+06 RESRAD Default NR NR NR NR Accuracy for water/soil computations 3

D 1.00E-03 RESRAD Default NR NR NR NR Saturated Zone Hydrological Data Density of saturated zone (g/cm3)

P 1

S Truncated Normal NUREG 6697 distribution for site soil type - sand 1.51 0.16 0.001 0.999 1.51 Saturated zone total porosity P

1 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.43 0.06 0.001 0.999 0.43 Saturated zone effective porosity P

1 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.383 0.0610 0.001 0.999 0.383 Saturated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-116 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Saturated zone hydraulic conductivity (m/y)

P 1

S Loguniform Site-specific distribution from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Saturated zone hydraulic gradient P

2 S

Bounded Lognormal - N NUREG/CR-6697 Att. C

-5.11 1.77 0.00007 0.5 0.006 Saturated zone b parameter P

2 D

NA saturated zone b not active because water table drop rate =0 NUREG/CR-6697 Att. C NR NR NR NR NR Water table drop rate (m/y)

P 3

D 0

Well pumping rate assumed small relative to water table volume.

NR NR NR NR Well pump intake depth (m below water table)

P 2

S Triangular NUREG/CR-6697 6

10 30 10 Model: Non-dispersion (ND) or Mass-Balance (MB)

P 3

D ND Non Dispersion Model used NR NR NR NR Well pumping rate (m3/y)

B,P 2

S 2250 Calculated according to method described in NUREG/CR-6697, Att. C Section 3.10 using Illinois specific irrigation rate and NUREG/CR-5512 vol. 3 livestock water intake rate NR NR NR NR NR Unsaturated Zone Hydrological Data Number of unsaturated zone strata P

3 D

1 One unsaturated zone NA NA NA NA Unsat. zone thickness (m)

P 1

D 3.45 (for 0.15 m contaminated zone thickness) 2.6 (for 1.0 m contaminated zone thickness)

Distance from ground surface (591) to water table (579) = 3.6 Reference 6-21, Tables 5.1 and 5.2 For 0.15 m contaminated zone thickness unsaturated zone = 3.6 - 0.15 = 3.45 m For 1.0 m contaminated zone thickness unsaturated zone = 3.6 - 1.0 = 2.6 m NA NA NA NA Unsat. zone soil density (g/cm3)

P 2

S Truncated Normal NUREG 6697 distribution for site soil type - sand 1.51 0.16 0.001 0.999 1.51 Unsat. zone total porosity P

2 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.43 0.06 0.001 0.999 0.43

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-117 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Unsat. zone effective porosity P

2 S

Truncated Normal NUREG 6697 distribution for site soil type - sand 0.383 0.0610 0.001 0.999 0.383 Unsat. zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Unsat. zone hydraulic conductivity (m/y)

P 2

S Loguniform Site-specific distribution from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Unsat. zone soil-specific b parameter P

2 S

Truncated Lognormal - N NUREG 6697 distribution for site soil type - sand

-.0253 0.216 0.001 0.999 0.97 Occupancy Inhalation rate (m3/y)

M,B 3

D 8400 NUREG/CR-5512, Vol. 3 Table 6.29 (23 m3/d x 365 d)

NR NR NR NR Mass loading for inhalation (g/m3)

P,B 2

S Continuous Linear NUREG/CR-6697, Att. C See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 2.35E-05 Exposure duration B

3 D

30 RESRAD Users Manual (Parameter not used in dose calculation)

NR NR NR NR Indoor dust filtration factor P,B 2

S Uniform NUREG/CR-6697, Att. C 0.15 0.95 0.55 Shielding factor, external gamma P

2 S

Bounded Lognormal - N NUREG/CR-6697, Att. C

-1.3 0.59 0.044 1

0.2725 Fraction of time spent indoors B

3 D

0.649 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Fraction of time spent outdoors (on site)

B 3

D 0.124 NUREG/CR-5512, Vol. 3 Table 6.87 (outdoors +

gardening)

NR NR NR NR Shape factor flag, external gamma P

3 D

Circular Circular contaminated zone assumed for modeling purposes NR NR NR NR Ingestion, Dietary Fruits, non-leafy vegetables, grain consumption (kg/y)

M,B 2

D 112 NUREG/CR-5512, Vol. 3 Table 6.87 (other vegetables + fruits + grain)

NR NR NR NR Leafy vegetable consumption (kg/y) M,B 3

D 21.4 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-118 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Milk consumption (L/y)

M,B 2

D 233 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry consumption (kg/y) M,B 3

D 65.1 NUREG/CR5512, Vol. 3 Table 6.87 (beef + poultry) NR NR NR NR Fish consumption (kg/y)

M,B 3

D 20.6 NUREG/CR-5512, Vol. 3 Table 6.87 Note: Aquatic Pathway inactive NR NR NR NR Other seafood consumption (kg/y)

M,B 3

D 0.9 RESRAD Users Manual Table D.2 Note: Aquatic Pathway inactive NR NR NR NR Soil ingestion rate (g/y)

M,B 2

D 18.3 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Drinking water intake (L/y)

M,B 2

D 478 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Contamination fraction of drinking water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of household water (if used)

B,P 3

NA Contamination fraction of livestock water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of irrigation water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of aquatic food B,P 2

D NA Assumption that pond is constructed that intercepts contaminated water not credible at Zion site NR NR NR NR Contamination fraction of plant food B,P 3

D 1

100% of food consumption assumed contaminated NR NR NR NR Contamination fraction of meat B,P 3

D 1

100% of food consumption assumed contaminated NR NR NR NR Contamination fraction of milk B,P 3

D 1

100% of food consumption assumed contaminated NR NR NR NR Ingestion, Non-Dietary

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-119 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Livestock fodder intake for meat (kg/day)

M 3

D 28.3 NUREG/CR5512, Vol. 3 Table 6.87 (forage, grain and hay for beef cattle +

poultry + layer hen)

NR NR NR NR Livestock fodder intake for milk (kg/day)

M 3

D 65.2 NUREG/CR5512, Vol. 3 Table 6.87 (forage + grain +

hay)

NR NR NR NR Livestock water intake for meat (L/day)

M 3

D 50.6 NUREG/CR5512, Vol. 3 Table 6.87 (beef cattle +

poultry + layer hen)

NR NR NR NR Livestock water intake for milk (L/day)

M 3

D 60 NUREG/CR5512, Vol. 3 Table 6.87 NR NR NR NR Livestock soil intake (kg/day)

M 3

D 0.5 RESRAD Users Manual, Appendix L NR NR NR NR Mass loading for foliar deposition (g/m3)

P 3

D 4.00E-04 NUREG/CR-5512, Vol. 3 Table 6.87, gardening NR NR NR NR Depth of soil mixing layer (m)

P 2

S Triangular NUREG/CR-6697, Att. C 0

0.15 0.6 0.23 Depth of roots (m)

P 1

S Uniform NUREG/CR-6697, Att. C 0.3 4.0 2.15 Drinking water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Household water fraction from ground water (if used)

B,P 3

NA Livestock water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Irrigation fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Wet weight crop yield for Non-Leafy (kg/m2)

P 2

S Truncated Lognormal - N NUREG/CR-6697, Att. C 0.56 0.48 0.001 0.999 1.75 Wet weight crop yield for Leafy (kg/m2)

P 3

D 2.90 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet weight crop yield for Fodder (kg/m2)

P 3

D 1.90 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Non-Leafy (y)

P 3

D 0.246 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Leafy (y)

P 3

D 0.123 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Fodder (y)

P 3

D 0.082 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Non-Leafy P

3 D

0.1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-120 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Translocation Factor for Leafy P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Fodder P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Weathering Removal Constant for Vegetation (1/y)

P 2

S Triangular NUREG/CR-6697, Att. C 5.1 18 84 33 Wet Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet Foliar Interception Fraction for Leafy P

2 D

Triangular NUREG/CR-6697, Att. C 0.06 0.67 0.95 0.58 Wet Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Storage times of contaminated foodstuffs (days):

Fruits, non-leafy vegetables, and grain B

3 D

14 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Leafy vegetables B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 (holdup period for beef = 20d and poultry

=1 day. Lowest value used)

NR NR NR NR Fish B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive NR NR NR NR Crustacea and mollusks B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive NR NR NR NR Well water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-121 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Surface water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Livestock fodder B

3 D

45 RESRAD Users Manual Table D.6 NR NR NR NR Special Radionuclides (C-14)

C-12 concentration in water (g/cm3) P 3

D NA NA NR NR NR NR C-12 concentration in contaminated soil (g/g)

P 3

D NA NA NR NR NR NR Fraction of vegetation carbon from soil P

3 D

NA NA NR NR NR NR Fraction of vegetation carbon from air P

3 D

NA NA NR NR NR NR C-14 evasion layer thickness in soil (m)

P 2

D NA NA NR NR NR NR C-14 evasion flux rate from soil (1/sec)

P 3

D NA NA NR NR NR NR C-12 evasion flux rate from soil (1/sec)

P 3

D NA NA NR NR NR NR Fraction of grain in beef cattle feed B 3

D NA NA NR NR NR NR Fraction of grain in milk cow feed B

3 D

NA NA NR NR NR NR Dose Conversion Factors (Inhalation mrem/pCi)

Co-60 M

3 D

2.19E-04 FGR11 NR NR NR NR Cs-134 M

3 D

4.62E-05 FGR11 NR NR NR NR Cs-137 M

3 D

3.19E-05 FGR11 NR NR NR NR Ni-63 M

3 D

6.29E-06 FGR11 NR NR NR NR Sr-90 M

3 D

1.30E-03 FGR11 NR NR NR NR Dose Conversion Factors (Ingestion mrem/pCi)

Co-60 M

3 D

2.69E-05 FGR11 NR NR NR NR Cs-134 M

3 D

7.33E-05 FGR11 NR NR NR NR Cs-137 M

3 D

5.00E-05 FGR11 NR NR NR NR Ni-63 M

3 D

5.77E-07 FGR11 NR NR NR NR

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-122 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Sr-90 M

3 D

1.42E-04 FGR11 NR NR NR NR Plant Transfer Factors (pCi/g plant)/(pCi/g soil)

Co-60 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-2.53 0.9 7.9E-02 Cs-134 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Cs-137 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Ni-63 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-3.00 0.9 5.0E-02 Sr-90 P

1 S

Lognormal - N NUREG/CR-6697, Att. C

-1.20 1.0 3.0E-01 Meat Transfer Factors (pCi/kg)/(pCi/d)

Co-60 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.51 1.0 3.0E-02 Cs-134 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Cs-137 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Ni-63 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-5.30 0.9 5.0E-03 Sr-90 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.61 0.4 1.0E-02 Milk Transfer Factors (pCi/L)/(pCi/d)

Co-60 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 0.7 2.0E-03 Cs-134 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Cs-137 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Ni-63 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-3.91 0.7 2.0E-02 Sr-90 P

2 S

Lognormal - N NUREG/CR-6697, Att. C

-6.21 0.5 2.0E-03 Bioaccumulation Factors for Fish ((pCi/kg)/(pCi/L))

Co-60 P

2 NA Inactive NUREG/CR-6697, Att. C 5.7 1.1 3.0E+02

RESRAD Input Parameters for ZSRP Soil Uncertainty Analysis 6-123 Parameter (unit)

Typea Priorityb Treatmentc Value/Distribution Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Cs-134 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Cs-137 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Ni-63 P

2 NA Inactive NUREG/CR-6697, Att. C 4.6 1.1 9.9E+01 Sr-90 P

2 NA Inactive NUREG/CR-6697, Att. C 4.1 1.1 6.0E+01 Bioaccumulation Factors for Crustacea/ Mollusks ((pCi/kg)/(pCi/L))

Co-60 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-134 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-137 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Ni-63 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Sr-90 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Graphics Parameters Number of points 32 RESRAD Default NR NR NR NR Spacing log RESRAD Default NR NR NR NR Time integration parameters Maximum number of points for dose 17 RESRAD Default NR NR NR NR Notes:

a P = physical, B = behavioral, M = metabolic; (see NUREG/CR-6697, Attachment B, Table 4.)

b 1 = high-priority parameter, 2 = medium-priority parameter, 3 = low-priority parameter (see NUREG/CR-6697, Attachment B, Table 4.1) c D = deterministic, S = stochastic d Distributions Statistical Parameters:

Lognormal-n: 1= mean, 2 = standard deviation Bounded lognormal-n: 1= mean, 2 = standard deviation, 3 = minimum, 4 = maximum Truncated lognormal-n: 1= mean, 2 = standard deviation, 3 = lower quantile, 4 = upper quantile Bounded normal: 1 = mean, 2 = standard deviation, 3 = minimum, 4 = maximum Beta: 1 = minimum, 2 = maximum, 3 = P-value, 4 = Q-value Triangular: 1 = minimum, 2 = mode, 3 = maximum Uniform: 1 = minimum, 2 = maximum

ZION STATION RESTORATION PROJECT LICENSE TERMINATION PLAN REVISION 2 6-124 ATTACHMENT 4 RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-125 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Soil Concentrations Basic radiation dose limit (mrem/y) 3 D

25 10 CFR 20.1402 NR NR NR NR Initial principal radionuclide (pCi/g)

P 2

D 1

Unit Value NR NR NR NR Distribution coefficients (contaminated, unsaturated, and saturated zones) (cm3/g)

Co-60 P

1 D

1161 TSD 14-0042 5.46 2.53 0.001 0.999 235 Cs-134 P

1 D

615 TSD 14-0042 6.1 2.33 0.001 0.999 446 Cs-137 P

1 D

615 TSD 14-0042 6.1 2.33 0.001 0.999 446 Ni-63 P

1 D

62 TSD 14-0042 6.05 1.46 0.001 0.999 424 Sr-90 P

1 D

2.3 TSD 14-0042 3.45 2.12 0.001 0.999 32 Initial concentration of radionuclides present in groundwater (pCi/l)

P 3

D 0

No existing groundwater contamination NR NR NR NR Calculation Times Time since placement of material (y) P 3

D 0

RESRAD Default NR NR NR NR Time for calculations (y)

P 3

D 0, 1, 3, 10, 30, 100, 300, 1000 RESRAD Default NR NR NR NR Contaminated Zone Area of contaminated zone (m2)

P 2

D 64,500 Area of the Security Protected Area on Zion Site NR NR NR NR Thickness of contaminated zone (m) P 2

D 0.15 or 1.0 Surface Soil Depth = 0.15m Subsurface Soil Depth = 1m NR NR NR NR Length parallel to aquifer flow (m)

P 2

D 287 Diameter of 64,500 m2 contaminated area.

NR NR NR NR Does the initial contamination penetrate the water table?

NA NA NA No No initial contamination in water table NA NA NA NA Contaminated fraction below water table Pe 3e D

0 No initial contamination in water table NR NR NR NR Cover and Contaminated Zone Hydrological Data Cover depth (m)

P 2

D 0

No Cover NR NR NR NR NA Density of cover (g/cm3)

P 1

NA NA No Cover NA NA NA NA NA Cover erosion rate (m/y)

P,B 2

NA NA No Cover NA NA NA NA NA Density of contaminated zone (g/cm3)

P 1

D 1.8 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.5.

1.51 0.16 0.001 0.999 1.51

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-126 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Contaminated zone erosion rate (m/y)

P,B 2

D 0.0015 Median NUREG/CR-6697 Att. C 5E-08 0.0007 0.005 0.2 0.0015 Contaminated zone total porosity P

2 D

0.35 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.6 0.43 0.06 0.001 0.999 0.43 Contaminated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Contaminated zone hydraulic conductivity (m/y)

P 2

D 2880 Site-specific value from Reference 6-21, Table 5.9 786 17000 NA NA 3649 Contaminated zone b parameter P

2 D

0.97 Median NUREG 6697 distribution for site soil type - sand

-0.0253 0.216 NA NA 0.97 Humidity in air (g/m3)

P 3

D 7.2 Median NUREG/CR-6697 Att. C 1.98 0.334 0.001 0.999 7.2 Evapotranspiration coefficient P

2 D

0.625 Median NUREG/CR-6697 Att. C 0.5 0.75 NR NR 0.625 Average annual wind speed (m/s)

P 2

D 4.2 Median NUREG/CR-6697 Att. C 1.445 0.2419 1.4 13 4.2 Precipitation (m/y)

P 2

D 0.83 Site-specific value from Reference 6-21, Table 5.12 NR NR NR NR Irrigation (m/y)

B 3

D 0.19 NUREG-5512, Vol. 3, Table 6-18 (Illinois Average)

NR NR NR NR Irrigation mode B

3 D

Overhead Overhead irrigation is common practice in U. S.

NR NR NR NR Runoff coefficient P

2 D

0.2 Site-specific value from Reference 6-21, Section 5.10 0.1 0.8 NR NR 0.45 Watershed area for nearby stream or pond (m2)

P 3

D 1.0E+06 RESRAD Default NR NR NR NR Accuracy for water/soil computations 3

D 1.00E-03 RESRAD Default NR NR NR NR Saturated Zone Hydrological Data Density of saturated zone (g/cm3)

P 2

D 1.8 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.5.

1.51 0.16 0.001 0.999 1.52 Saturated zone total porosity P

1 D

0.35 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.6 0.43 0.0699 0.214 0.646 0.43

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-127 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Saturated zone effective porosity P

1 D

0.29 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.7 0.43 0.06 0.001 0.999 0.43 Saturated zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Saturated zone hydraulic conductivity (m/y)

P 1

D 2880 Site-specific average from Reference 6-21, Table 5.9.

786 17000 NA NA 3649 Saturated zone hydraulic gradient P

2 D

0.0039 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.10

-5.11 1.77 0.00007 0.5 0.006 Saturated zone b parameter P

2 D

NA saturated zone b not active because water table drop rate =0 NUREG/CR-6697, Att. A, Table 2 NR NR NR NR NR Water table drop rate (m/y)

P 3

D 0

Well pumping rate assumed small relative to water table volume.

NR NR NR NR Well pump intake depth (m below water table)

P 2

D 3.3 Mid-point of Shallow Aquifer Reference 6-21, Table 5.1 NA NA NA NA Model: Non-dispersion (ND) or Mass-Balance (MB)

P 3

D ND Non-dispersion model used NR NR NR NR Well pumping rate (m3/y)

P 2

D 2250 Calculated according to method described in NUREG/CR-6697, Att. C Section 3.10using Illinois specific irrigation rate and NUREG/CR-5512 vol. 3 livestock water intake rate NR NR NR NR NR Unsaturated Zone Hydrological Data Number of unsaturated zone strata P

3 D

1 One unsaturated zone NA NA NA NA

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-128 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Unsat. zone thickness (m)

P 1

D 3.45 (for 0.15 m contaminated zone thickness) 2.6 (for 1.0 m contaminated zone thickness)

Distance from ground surface (591) to water table (579) = 3.6 Reference 6-21, Tables 5.1 and 5.2 For 0.15 m contaminated zone thickness unsaturated zone = 3.6 - 0.15 = 3.45 m For 1.0 m contaminated zone thickness unsaturated zone = 3.6 - 1.0 = 2.6 m NA NA NA NA Unsat. zone soil density (g/cm3)

P 2

D 1.8 Site-specific value from Reference 6-21, Table 5.5 NA NA NA NA Unsat. zone total porosity P

1 D

0.35 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.6 0.43 0.0699 0.214 0.646 0.43 Unsat. zone effective porosity P

1 D

0.29 Site-specific average native sand and disturbed sand from Reference 6-21, Table 5.7 0.342 0.0705 0.124 0.56 0.342 Unsat. zone field capacity P

3 D

0.066 Site-specific value from Reference 6-21, Table 5.4 NR NR NR NR Unsat. zone hydraulic conductivity (m/y)

P 2

D 2880 Site-specific average from Reference 6-21, Table 5.9. -0.511 1.77 0.00007 0.5 0.006 Unsat. zone soil-specific b parameter P

2 D

0.97 Median NUREG/CR-6697 Att. C Sand soil type

-0.0253 0.216 0.501 1.90 0.97 Occupancy Inhalation rate (m3/y)

M,B 3

D 8400 NUREG/CR-5512, Vol. 3 Table 6.29

(=23 m3/d x 365 d/y)

NR NR NR NR Mass loading for inhalation (g/m3)

P,B 2

D 2.35E-05 Median NUREG/CR-6697, Att. C See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 See NUREG-6697 Table 4.6-1 2.35E-05 Exposure duration B

3 D

30 RESRAD Users Manual (Parameter not used in dose calculation)

NR NR NR NR

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-129 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Indoor dust filtration factor P,B 2

D 0.55 Median NUREG/CR-6697, Att. C 0.15 0.95 0.55 Shielding factor, external gamma P

2 D

0.40 75th Percentile NUREG/CR-6697, Att. C

-1.3 0.59 0.044 1

0.272 Fraction of time spent indoors B

3 D

0.649 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Fraction of time spent outdoors (on site)

B 3

D 0.124 NUREG/CR-5512, Vol. 3 Table 6.87 (outdoors +

gardening)

NR NR NR NR Shape factor flag, external gamma P

3 D

Circular Circular contaminated zone assumed for modeling purposes NR NR NR NR Ingestion, Dietary Fruits, non-leafy vegetables, grain consumption (kg/y)

M,B 2

D 112 NUREG/CR-5512, Vol. 3 Table 6.87 (other vegetables + fruits + grain)

NR NR NR NR Leafy vegetable consumption (kg/y) M,B 3

D 21.4 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk consumption (L/y)

M,B 2

D 233 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Meat and poultry consumption (kg/y) M,B 3

D 65.1 NUREG/CR5512, Vol. 3 Table 6.87 (beef + poultry) NR NR NR NR Fish consumption (kg/y)

M,B 3

D 20.6 NUREG/CR-5512, Vol. 3 Table 6.87 Note: Aquatic Pathway inactive NR NR NR NR Other seafood consumption (kg/y)

M,B 3

D 0.9 RESRAD Users Manual Table D.2 Note: Aquatic Pathway inactive NR NR NR NR Soil ingestion rate (g/y)

M,B 2

D 18.3 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Drinking water intake (L/y)

M,B 2

D 478 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Contamination fraction of drinking water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of household water (if used)

B,P 3

NA Contamination fraction of livestock water B,P 3

D 1

All water assumed contaminated NR NR NR NR

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-130 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Contamination fraction of irrigation water B,P 3

D 1

All water assumed contaminated NR NR NR NR Contamination fraction of aquatic food B,P 2

D NA Assumption that pond is constructed that intercepts contaminated water not credible at Zion site NR NR NR NR Contamination fraction of plant food B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Contamination fraction of meat B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Contamination fraction of milk B,P 3

D 1

100% of food consumption rate from onsite source NR NR NR NR Ingestion, Non-Dietary Livestock fodder intake for meat (kg/day)

M 3

D 28.3 NUREG/CR5512, Vol. 3 Table 6.87 (forage, grain and hay for beef cattle +

poultry + layer hen)

NR NR NR NR Livestock fodder intake for milk (kg/day)

M 3

D 65.2 NUREG/CR5512, Vol. 3 Table 6.87 (forage + grain +

hay)

NR NR NR NR Livestock water intake for meat (L/day)

M 3

D 50.6 NUREG/CR5512, Vol. 3 Table 6.87 (beef cattle +

poultry + layer hen)

NR NR NR NR Livestock water intake for milk (L/day)

M 3

D 60 NUREG/CR5512, Vol. 3 Table 6.87 NR NR NR NR Livestock soil intake (kg/day)

M 3

D 0.5 RESRAD Users Manual, Appendix L NR NR NR NR Mass loading for foliar deposition (g/m3)

P 3

D 4.00E-04 NUREG/CR-5512, Vol. 3 Table 6.87, gardening NR NR NR NR Depth of soil mixing layer (m)

P 2

D 0.15 for Surface Soil 0.23 for Subsurface Soil 25th Percentile NUREG/CR-6697, Att. C Median NUREG/CR-6697, Att. C 0

0.15 0.6 0.23 Depth of roots (m)

P 1

D 1.22 25th Percentile NUREG/CR-6697, Att. C 0.3 4.0 2.15 Drinking water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Household water fraction from ground water (if used)

B,P 3

NA Livestock water fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-131 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Irrigation fraction from ground water B,P 3

D 1

All water assumed to be supplied from groundwater NR NR NR NR Wet weight crop yield for Non-Leafy (kg/m2)

P 2

D 1.75 Median NUREG/CR-6697, Att. C 0.56 0.48 0.001 0.999 1.75 Wet weight crop yield for Leafy (kg/m2)

P 3

D 2.90 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet weight crop yield for Fodder (kg/m2)

P 3

D 1.90 NUREG/CR-5512, Vol. 3 Table 6.87 (maximum of forage, grain and hay)

NR NR NR NR Growing Season for Non-Leafy (y)

P 3

D 0.246 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Leafy (y)

P 3

D 0.123 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Growing Season for Fodder (y)

P 3

D 0.082 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Non-Leafy P

3 D

0.1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Leafy P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Translocation Factor for Fodder P

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Weathering Removal Constant for Vegetation (1/y)

P 2

D 33 Median NUREG/CR-6697, Att. C 5.1 18 84 33 Wet Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Wet Foliar Interception Fraction for Leafy P

2 D

0.58 Median NUREG/CR-6697, Att. C 0.06 0.67 0.95 0.58 Wet Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Non-Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Leafy P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Dry Foliar Interception Fraction for Fodder P

3 D

0.35 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Storage times of contaminated foodstuffs (days):

Fruits, non-leafy vegetables, and grain B

3 D

14 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Leafy vegetables B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR Milk B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 NR NR NR NR

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-132 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Meat and poultry B

3 D

1 NUREG/CR-5512, Vol. 3 Table 6.87 (holdup period for beef = 20d and poultry

=1 day. Lowest value used)

NR NR NR NR Fish B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive in BFM NR NR NR NR Crustacea and mollusks B

3 D

7 RESRAD Users Manual Table D.6 Note: Aquatic pathway inactive in BFM NR NR NR NR Well water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Surface water B

3 D

1 RESRAD Users Manual Table D.6 NR NR NR NR Livestock fodder B

3 D

45 RESRAD Users Manual Table D.6 NR NR NR NR Special Radionuclides (C-14)

C-12 concentration in water (g/cm3) P 3

D NA NA NR NR NR NR C-12 concentration in contaminated soil (g/g)

P 3

D NA NA NR NR NR NR Fraction of vegetation carbon from soil P

3 D

NA NA NR NR NR NR Fraction of vegetation carbon from air P

3 D

NA NA NR NR NR NR C-14 evasion layer thickness in soil (m)

P 2

D NA NA NR NR NR NR C-14 evasion flux rate from soil (1/sec)

P 3

D NA NA NR NR NR NR C-12 evasion flux rate from soil (1/sec)

P 3

D NA NA NR NR NR NR Fraction of grain in beef cattle feed B 3

D NA NA NR NR NR NR Fraction of grain in milk cow feed B

3 D

NA NA NR NR NR NR Dose Conversion Factors (Inhalation mrem/pCi)

Co-60 M

3 D

2.19E-04 FGR11 NR NR NR NR Cs-134 M

3 D

4.62E-05 FGR11 NR NR NR NR Cs-137 M

3 D

3.19E-05 FGR11 NR NR NR NR

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-133 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Ni-63 M

3 D

6.29E-06 FGR11 NR NR NR NR Sr-90 M

3 D

1.30E-03 FGR11 NR NR NR NR Dose Conversion Factors (Ingestion mrem/pCi)

Co-60 M

3 D

2.69E-05 FGR11 NR NR NR NR Cs-134 M

3 D

7.33E-05 FGR11 NR NR NR NR Cs-137 M

3 D

5.00E-05 FGR11 NR NR NR NR Ni-63 M

3 D

5.77E-07 FGR11 NR NR NR NR Sr-90 M

3 D

1.42E-04 FGR11 NR NR NR NR Plant Transfer Factors (pCi/g plant)/(pCi/g soil)

Co-60 P

1 D

1.5E-01 75th Percentile NUREG/CR-6697, Att. C

-2.53 0.9 7.9E-02 Cs-134 P

1 D

7.8E-02 75th Percentile NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Cs-137 P

1 D

7.8E-02 75th Percentile NUREG/CR-6697, Att. C

-3.22 1.0 4.0E-02 Ni-63 P

1 D

9.2E-02 75th Percentile NUREG/CR-6697, Att. C

-3.00 0.9 5.0E-02 Sr-90 P

1 D

5.9E-01 75th Percentile NUREG/CR-6697, Att. C

-1.20 1.0 3.0E-01 Meat Transfer Factors (pCi/kg)/(pCi/d)

Co-60 P

2 D

5.8E-02 75th Percentile NUREG/CR-6697, Att. C

-3.51 1.0 3.0E-02 Cs-134 P

2 D

6.5E-02 75th Percentile NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Cs-137 P

2 D

6.5E-02 75th Percentile NUREG/CR-6697, Att. C

-3.00 0.4 5.0E-02 Ni-63 P

2 D

5E-03 Median NUREG/CR-6697, Att. C

-5.30 0.9 5.0E-03 Sr-90 P

2 D

8E-03 Median NUREG/CR-6697, Att. C

-4.61 0.4 1.0E-02 Milk Transfer Factors (pCi/L)/(pCi/d)

Co-60 P

2 D

2E-03 Median NUREG/CR-6697, Att. C

-6.21 0.7 2.0E-03 Cs-134 P

2 D

1.4E-02 75th Percentile NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Cs-137 P

2 D

1.4E-02 75th Percentile NUREG/CR-6697, Att. C

-4.61 0.5 1.0E-02 Ni-63 P

2 D

3.2E-02 75th Percentile NUREG/CR-6697, Att. C

-3.91 0.7 2.0E-02

RESRAD Input Parameters for ZSRP Surface Soil and Subsurface Soil DCGL 6-134 Parameter (unit)

Typea Priorityb Treatmentc Value Basis Distribution's Statistical Parametersd 1

2 3

4 Mean/

Median Sr-90 P

2 D

2.7E-03 75th Percentile NUREG/CR-6697, Att. C

-6.21 0.5 2.0E-03 Bioaccumulation Factors for Fish ((pCi/kg)/(pCi/L))

Co-60 P

2 NA Inactive NUREG/CR-6697, Att. C 5.7 1.1 3.0E+02 Cs-134 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Cs-137 P

2 NA Inactive NUREG/CR-6697, Att. C 7.6 0.7 2.0E+03 Ni-63 P

2 NA Inactive NUREG/CR-6697, Att. C 4.6 1.1 9.9E+01 Sr-90 P

2 NA Inactive NUREG/CR-6697, Att. C 4.1 1.1 6.0E+01 Bioaccumulation Factors for Crustacea/ Mollusks ((pCi/kg)/(pCi/L))

Co-60 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-134 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Cs-137 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Ni-63 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Sr-90 P

3 NA Inactive RESRAD Users Manual Appendix D NR NR NR NR Graphics Parameters Number of points 32 RESRAD Default NR NR NR NR Spacing log RESRAD Default NR NR NR NR Time integration parameters Maximum number of points for dose 17 RESRAD Default NR NR NR NR Notes: a P = physical, B = behavioral, M = metabolic; (see NUREG/CR-6697, Attachment B, Table 4.)

b 1 = high-priority parameter, 2 = medium-priority parameter, 3 = low-priority parameter (see NUREG/CR-6697, Attachment B, Table 4.1) c D = deterministic, S = stochastic d Distributions Statistical Parameters:

Lognormal-n: 1= mean, 2 = standard deviation Bounded lognormal-n: 1= mean, 2 = standard deviation, 3 = minimum, 4 = maximum Truncated lognormal-n: 1= mean, 2 = standard deviation, 3 = lower quantile, 4 = upper quantile Bounded normal: 1 = mean, 2 = standard deviation, 3 = minimum, 4 = maximum Beta: 1 = minimum, 2 = maximum, 3 = P-value, 4 = Q-value Triangular: 1 = minimum, 2 = mode, 3 = maximum Uniform: 1 = minimum, 2 = maximum

ML18052A958

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