ML24214A079

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Enclosure 23: Tsd 24-063, Basement Fill Model: Calculation of Dcglw/F Values Assuming Industrial Use Scenario Exposure Pathways, Revision 0
ML24214A079
Person / Time
Site: Oyster Creek
Issue date: 07/08/2024
From: Bisson J
Holtec Decommissioning International, Radiation Safety & Control Services
To:
Office of Nuclear Reactor Regulation
Shared Package
ML24214A209 List:
References
HDI-OC-24-018 RSCS TSD 24-063, Rev 0
Download: ML24214A079 (1)
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Text

OFFICIAL USE ONLY / USAGE EXCLUSIF Distribution Coefficient (Kd) of Radionuclides in Soil Samples from Chalk River Laboratories RSCS TSD 24-017 Rev 0 D1 Page 1 of 44

Basement Fill Model: Calculation of DCGLW/F Values Assuming Industrial Use Scenario Exposure Pathways

Technical Support Document No.24-063 Revision 0

Prepared by: ______________________________________________________

Joseph Bisson, Technical Consultant

Reviewed by:

Christopher C. Messier, Sr. Director of Engineering

Approved by: ______________________________________________________

Eric Darois, CHP, Executive Director

Radiation Safety & Control Services, Inc 93 Ledge Road, Seabrook, NH 03874 1-800-525-8339 (603) 778-2871 (Outside USA) www.radsafety.com RSCS July 8, 2024 Radiation Safety & Control Services

91 Portsmouth Avenue, Stratham, NH 03885-2468 phone: 1-800 - 525-8339

  • fax: 603 -77 8 - 6879 i nfo@rad safety. com www. r ad safety. com Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Contents 1 Introduction........................................................................................................................... 3 2 Method of Calculation........................................................................................................... 3 3 Input and Calculations........................................................................................................... 4 3.1 DCGLIR Calculations................................................................................................................. 4 3.2 DCGLDS Calculations.............................................................................................................. 21 3.3 DCGLEC Calculations.............................................................................................................. 24 3.4 DCGLW/F Calculations............................................................................................................ 27 4 References........................................................................................................................... 28

Page 2 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

1 Introduction

This calculation documents the development of Basement Fill Model (BFM) derived concentration guideline level values for the walls and floors (DCGLW/F) applying the exposure pathways assumed for the Industrial Use (IU) scenario to support the assessment of below-grade concrete structures at the Oyster Creek Nuclear Generating Station (OCNGS) site.

The OCNGS IU scenario assumes the critical receptor is a hypothetical full-time industrial site worker assigned outdoor tasks who also catches and consumes fish from the intake/discharge canal during off -hours. The pathways used to estimate radiation exposure resulting from residual radioactivity in the soil for this scenario are:

  • Direct external radiation exposure pathway
  • Inhalation exposure pathway
  • Ingestion exposure via aquatic food from the intake/discharge canal
  • Inadvertent ingestion of contaminated soil The DCGLW/F values developed in this document correspond to the NRC dose criteria established in 10CFR20.1403 (i.e., 25 mrem/y). This calculation addresses only the development of BFM DCGLW/F values for the OCNGS site.

2 Method of Calculation

The BFM DCGLW/F values based on IU assumptions incorporate 3 scenarios: (1) an instantaneous release (IR) scenario, (2) drilling spoils (DS) scenario, and an excavated concrete (EC) scenario. Each scenario is evaluated separately in this calculation. Radionuclide-specific DCGL values are calculated for each scenario and summed to produce the final DCGLW/F values.

IR scenario: Calculations for DCGLIR values assumed the site modeling described in the probabilistic analysis for the IR scenario, TSD 24-055 [1]. Except for the 25th or 75th percentile values for risk-sensitive parameters, input values for RESRAD-Onsite parameters are the same as those used in the probabilistic analysis.

DS and EC scenarios: Calculations for DCGLDS and DCGLEC values are based on contaminated volume/area calculations with application of peak of the means (POM) doses and DCGL values documented in ENG -OCS-008 [2] and soil area factors (AFs) documented in ENG-OCS-009 [3].

Detailed assumptions and calculations for the IR scenario are provided in section 3.1, those for the DS scenario are provided in section 3.2, and those for the EC scenario are provided in section 3.3. Calculations of final BFM DCGLW/F values are found in section 3.4.

Page 3 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

3 Input and Calculations

A site-specific suite of potential radionuclides-of-concern (ROCs) has been identified for the OCNGS site [4]

and is listed in Table 1. RESRAD-Onsite 7.2 automatically accounts for progeny radionuclides with input for several of the OCS ROCs. Progeny radionuclides are also listed in Table 1.

Table 1: Potential Radionuclides of Concern Identified for the OCNGS Site ROCa Progenyb ROCa Progenyb Am-241 Np-237, Th-229, U-233 Nb-94 ---

C-14 --- Ni-63 ---

Cm-243 Ac-227, Am-243, Pa-231, Np-237 Th-229, U-233 Pu-239, U-235 Cm-244 Pu-240, Ra-228, Th-228, Pu-238 Pb-210, Po-210, Ra-226, Th-232, U-236 Th-230, U-234 Cs-137 --- Pu-239 Ac-227, Pa-231, U-235 Co-60 --- Pu-240 Ra-228, Th-228, Th-232, U-236 Eu-152 Gd-152 Pu-241 Am-241, Np-237, Th-229, U-233 Eu-154 --- Sb-125 Te-125m Fe-55 --- Sr-90 ---

H-3 --- Tc-99 ---

Mn-54 ---

a ROC = radionuclide-of-concern identified for the OCNGS site.

b Included automatically with the input of parent ROC.

3.1 DCGLIR Calculations The IR scenario assumes an instantaneous release of radioactive contamination from sub -surface concrete surfaces to fill material immediately adjacent within 1m from the concrete surfaces, thereby creating the scenarios contaminated volume (CV). RESRAD-Onsite modeling assumes that the CV is a homogenous mixture, covered by 3ft (0.91m) of site soil, and extends to a depth of 43ft (13.1m), the depth of the Reactor Building foundation walls. Site-specific modeling places portions of the CV above and below the average groundwater table. The below-grade concrete structures are assumed not to impede groundwater flow. The conceptual configuration of the contaminated zone (CZ) created by the CV is shown in Figure 1.

Page 4 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

., _____________________________________________________________________ I _________________________________ _

Figure 1 Conceptual Configuration of the CV (note: not to scale)

Input for RESRAD-Onsite parameters includes the 75th percentile and 25th percentile values of the distributions for risk-sensitive parameters (note: risk-sensitive parameters assuming the BFM IR scenario are identified in TSD 24-055).

The probabilistic mode of the RESRAD-Onsite code was used to calculate ROC-specific peak of the mean (POM) doses associated with soil concentrations equal to 1 pCi/g. The POM doses were then used to develop the DCGLIR values.

The input values for the RESRAD-Onsite parameters that define the CV were taken from TSD 24-055 and presented below.

Instantaneous release CV: 20,184 m3.

CZ area: 1539.6 m2.

Diameter of the CV = length parallel to aquifer flow parameter: 44.3m.

Fractions of CV below the groundwater table: 0.7326 All other inputs for RESRAD-Onsite parameters (e.g., soil type, kd values, hydrogeologic input, occupancy, dietary, etc.) are the same as those used in the probabilistic analyses (TSD 24-055). The value and basis for each RESRAD-Onsite parameter are provided in Table 2.

Page 5 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Table 2. BFM IR Scenario: Summary of Input Values for RESRAD-Onsite Parameters

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values RESRAD Exposure Pathways

External Gamma Open

Inhalation Open

Plant Ingestion Close

Meat Ingestion Close

Milk Ingestion Close

Aquatic Foods Open

Drinking Water Close

Soil Ingestion Open

Radon Close

Distribution's Statistical Median/

Parametersd Mean Parameter (unit) Typea Priorityb Treatmentc Value/Distribution Basis 1 2 3 4

Soil Concentrations

Basic radiation dose P 3 D 25 10 CFR 20.1402 NR NR NR NR limit (mrem/y)

Initial principal P 2 D 1 Unit Value NR NR NR NR radionuclide (pCi/g)

Distribution coefficients (cm3/g) for sand soil type assigned to CZ and SZ except as noted

Ac-227 P 1 S Truncated lognormal-n NUREG/CR-7267 [5] 7.44 1.1 0.001 0.999 1700

Am-241 P 1 D 2.69E+02 25th percentile value NR NR NR NR

Am-243 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 [6] 6.91 1.95 0.001 0.999 1000

C-14 P 1 D 6.13E+00 25th percentile value NR NR NR NR

Cm-243 P 1 D 5.74E+02 (CZ) 25th percentile value

S Truncated lognormal-n ANL/EVS/TM-14/4 8.13 2.64 0.001 0.999 3400 (SZ)

Page 6 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Cm-244 P 1 D 5.74E+02 (CZ) 25th percentile value

S Truncated lognormal-n ANL/EVS/TM-14/4 8.13 2.64 0.001 0.999 3400 (SZ)

Co-60 P 1 D 3.71E+01 25th percentile value NR NR NR NR

Cs-137 P 1 D 1.58E+02 25th percentile value NR NR NR NR

Eu-152 P 1 D 6.40E+01 25th percentile value NR NR NR NR

Eu-154 P 1 D 6.40E+01 25th percentile value NR NR NR NR

Fe-55 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 5.77 0 0.001 0.999 320

Gd-152 P 1 S Truncated lognormal-n NUREG/CR-7267 1.61 3.22 0.001 0.999 5

H-3 P 1 S Truncated lognormal-n NUREG/CR-7267 -2.81 0.5 0.001 0.999 0.06

Mn-54 P 1 D 1.66E+02 25th percentile value NR NR NR NR

Nb-94 P 1 D 3.81E+03 (CZ) 75th percentile value NR NR NR NR

S Truncated lognormal-n NUREG/CR-7267 7.31 1.39 0.001 0.999 1500 (SZ)

Ni-63 P 1 D 2.77E+01 25th percentile value NR NR NR NR

Np-237 P 1 D 5.49E+00 25th percentile value NR NR NR NR

Pa-231 P 1 S Truncated lognormal-n NUREG/CR-7267 7.6 1.1 0.001 0.999 2000

Pb-210 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 5.39 1.39 0.001 0.999 220

Po-210 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 4.61 1.79 0.001 0.999 100

Pu-238 P 1 D 1.56E+02 25th percentile value NR NR NR NR

Pu-239 P 1 D 1.56E+02 25th percentile value NR NR NR NR

Pu-240 P 1 D 1.56E+02 25th percentile value NR NR NR NR

Pu-241 P 1 D 1.57E+02 25th percentile value NR NR NR NR

Ra-226 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 8.04 2.08 0.001 0.999 3100

Ra-228 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 8.04 2.08 0.001 0.999 3100

Page 7 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Sb-125 P 1 D 5.07E+00 (CZ) 25th percentile value NR NR NR NR

S Truncated lognormal-n ANL/EVS/TM-14/4 2.83 1.79 0.001 0.999 17 (SZ)

Sr-90 P 1 D 6.58E+00 25th percentile value NR NR NR NR

Tc-99 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 -3.22 1.1 0.001 0.999 0.04

Te-125m P 1 S Truncated lognormal-n NUREG/CR-7267 6.31 3.22 0.001 0.999 550

Th-228 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 6.55 2.4 0.001 0.999 700

Th-229 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 6.55 2.4 0.001 0.999 700

Th-230 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 6.55 2.4 0.001 0.999 700

Th-232 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 6.55 2.4 0.001 0.999 700

U-233 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 4.7 2.48 0.001 0.999 110

U-234 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 4.7 2.48 0.001 0.999 110

U-235 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 4.7 2.48 0.001 0.999 110

U-236 P 1 S Truncated lognormal-n ANL/EVS/TM-14/4 4.7 2.48 0.001 0.999 110

Initial concentration P 3 D 0 Ground water NR NR NR NR of radionuclides uncontaminated present in groundwater (pCi/l)

Calculation Times

Time since placement P 3 D 0 NR NR NR NR of material (y)

Time for calculations P 3 D 0, 1, 3, 10, 30, 100, 300, RESRAD Default NR NR NR NR (y) 1000

Contaminated Zone

Area of contaminated P 2 D 1539.6 Based on contaminated NR NR NR NR zone (m2) volume and height of RB wall.

Thickness of P 2 D 13.1 CZ thickness set to RB wall NR NR NR NR contaminated zone height.

(m)

Page 8 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Length parallel to P 2 D 44.3 Set to diameter of CZ. NR NR NR NR aquifer flow (m)

Does the initial contamination penetrate the water Yes Based on site features and RB dimensions.

table?

Contaminated fraction below water table D.7326 Based on OCGS site data; NR NR NR NR average groundwater depths recorded for wells around the RB, TB, and ORB.

Cover and Contaminated Zone Hydrological Data

Cover depth (m) P 2 D 0.91 3ft cover assumed. NR NR NR NR

D 1.40E+00 (Co-60, Cs-137, 25th percentile value NR NR NR NR Eu-152, Eu-154, Mn-54, Nb-94, Sb-125)

Cover density (g/cm3) P 2 Truncated Normal (all S other ROCs) Site soil type = sand 1.5105 0.159 0.001 0.999 1.5105 (OCNGS Hydrogeologic Investigation Report).

Input for density of fill material = NUREG/CR-7267 density distribution for site soil type - sand.

Cover erosion rate P 2 D 6E-04 Assumed final site grade is NR NR NR NR (m/y) level. Input for erosion rate

= NUREG/CR-7267 erosion rate for site with shallow slope (i.e., relatively level)

Density of P 1 S Truncated Normal Site soil type = sand 1.5105 0.159 0.001 0.999 1.5105 contaminated zone (OCNGS Hydrogeologic (g/cm3) Investigation Report).

Input for density of fill material = NUREG/CR-7267 density distribution for site soil type - sand.

Contaminated zone P 2 D 6E-04 Assumed same as cover. NR NR NR NR erosion rate (m/y)

Contaminated zone P 2 S Bounded Normal NUREG/CR-7267 0.43 0.06 0.2446 0.6154 0.43 total porosity distribution for site soil type -sand

Page 9 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Contaminated zone P 3 D 0.18 Value based on site-NR NR NR NR field capacity specific soil type (sand);

calculated using equation in NUREG/CR-7267

Contaminated zone P 2 D 2741 OCNGS Hydrogeologic NR NR NR NR hydraulic Investigation Report conductivity (m/y)

Contaminated zone b P 2 S Bounded NUREG/CR-7267 - 0.0253 0.216 0.501 1.90 0.975 parameter Log Normal n distribution for site soil type - sand

Humidity in air (g/m3) P 3 D 6.6 From Regional and Site-NR NR NR NR Specific Absolute Humidity Data for Use in Tritium Dose Calculations.

Evapotranspiration P 2 D 5.62E-01 (Fe-55) 25th percentile value coefficient

S Uniform (all other ROCs) NUREG/CR-7267 0.5 0.75 NR NR 0.625 distribution

Average annual wind P 2 D 3.13 Internet search: NR NR NR NR speed (m/s) https://www.windfinder.c om/windstatistics/oyster_c reek_barnegat_bay

Precipitation (m/y) P 2 D 1.4 Annual Report on the NR NR NR NR Meteological Program at Oyster Creek Generating Station - average annual precipitation for 2015 through 2020

Irrigation (m/y) B 3 S Uniform Distribution determined 0 0.08 0.04 using methodology described in Data Collection Handbook and NUREG/CR-6697

Irrigation mode B 3 D Overhead Overhead irrigation is NR NR NR NR common practice for crops in U.S.

Runoff coefficient P 2 D 0.2 Value determined using NR NR NR NR methodology described in Data Collection Handbook and NUREG/CR-7267

Page 10 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Watershed area for P 3 D 1.01E+08 NJ-GeoWeb (NJDEP BGIS) NR NR NR NR nearby stream or pond (m2)

Accuracy for - 3 D 1.00E-03 RESRAD Default NR NR NR NR water/soil computations

Saturated Zone Hydrological Data

Density of saturated P 1 S Truncated Normal NUREG/CR-7267 1.5105 0.159 0.001 0.999 1.5105 zone (g/cm3) distribution for site soil

type -sand

Saturated zone total P 1 S Truncated Normal NUREG/CR-7267 0.43 0.06 0.001 0.999 0.43 porosity distribution for site soil type -sand

Saturated zone P 1 D 0.25 OCNGS Hydrogeologic NR NR NR NR effective porosity Investigation Report

Saturated zone field P 3 D 0.18 Value based on site-NR NR NR NR capacity specific soil type (sand);

calculated using equation in NUREG/CR-7267

Saturated zone P 1 D 2741 OCNGS Hydrogeologic NR NR NR NR hydraulic Investigation Report conductivity (m/y)

Saturated zone P 2 D 1.75E-02 (H-3, Nb-94, Tc-25th percentile value NR NR NR NR hydraulic gradient 99)

S Uniform (all other ROCs) OCNGS Hydrogeologic 0.01 0.04 0.025

Investigation Report

Saturated zone b P 2 S N/A Input not required when CZ NR NR NR NR parameter is in SZ

Water table drop rate P 3 D 0 CZ in SZ NR NR NR NR (m/y)

Well pump intake P 2 D 9.6 Input has no impact NR NR NR NR depth (m below because drinking water water table) exposure pathway is not an open pathway.

Page 11 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Model: P 3 D ND ND model recommended NR NR NR NR Nondispersion (ND) for contaminant areas or Mass-Balance >1,000 m2 (MB)

Well pumping rate P 2 S N/A Input not required. NR NR NR NR (m3/y)

Unsaturated Zone Hydrological Data

Unsaturated zones P 3 D 0 See Figure 1 NR NR NR NR

Unsat. zone 1, P 1 D N/A UZ strata set to 0; input for NR NR NR NR thickness (m) UZ parameters not used.

Unsat. zone 1, soil P 2 S N/A UZ strata set to 0; input for NR NR NR NR density (g/cm3) UZ parameters not used.

Unsat. zone 1, total P 2 S N/A UZ strata set to 0; input for NR NR NR NR porosity UZ parameters not used.

Unsat. zone 1, P 2 D N/A UZ strata set to 0; input for NR NR NR NR effective porosity UZ parameters not used.

Unsat. zone 1, field P 3 D N/A UZ strata set to 0; input for NR NR NR NR capacity UZ parameters not used.

Unsat. zone 1, P 2 D N/A UZ strata set to 0; input for NR NR NR NR hydraulic UZ parameters not used.

conductivity (m/y)

Unsat. zone 1, soil-P 2 S N/A UZ strata set to 0; input for NR NR NR NR specific b parameter UZ parameters not used.

Occupancy

Inhalation rate (m3/y) B 3 D 8400 NUREG/CR-7267 NR NR NR NR

Mass loading for P 2 S Continuous linear NUREG/CR-7267 2.3E-5 inhalation (g/m3)

Exposure duration B 3 D 30 RESRAD Default NR NR NR NR

Indoor dust filtration P 2 S Uniform NUREG/CR-7267 0.15 0.95 0.55 factor

Shielding factor, P 2 S Bounded lognormal-n NUREG/CR-7267 -1.3 0.59 0.044 1 0.2725 external gamma

Fraction of time spent B 3 D 0.03 Fraction of calendar year NR NR NR NR indoors assuming 1h/work day for daily work breaks

Page 12 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Fraction of time spent B 3 D 0.2 Fraction of calendar year NR NR NR NR outdoors assuming 7h/work day for outside tasks

Shape factor flag, P 3 D Circular Circular contaminated zone NR NR NR NR external gamma assumed

Ingestion, Dietary

Fruits, vegetables, B 2 D N/A Input not required - plant NR NR NR NR grain consumption ingestion pathway inactive (kg/y)

Leafy vegetable B 3 D N/A Input not required - plant NR NR NR NR consumption (kg/y) ingestion pathway inactive

Milk consumption B 2 D N/A Input not required - milk NR NR NR NR (L/y) ingestion pathway inactive

Meat and poultry B 3 D N/A Input not required - meat NR NR NR NR consumption (kg/y) ingestion pathway inactive

Fish consumption B 3 D 20.6 NUREG/CR-5512, Vol. 3 NR NR NR NR (kg/y)

Other seafood B 3 D 0.9 RESRAD Default NR NR NR NR consumption (kg/y)

Soil ingestion rate B 2 D Triangular NUREG/CR-7267 0 18.3 36.5 18.3 (g/yr)

Drinking water intake B 2 D N/A Input not required - NR NR NR NR (L/y) drinking water pathway inactive

Contamination P 3 D N/A Input not required - NR NR NR NR fraction of drinking drinking water pathway water inactive

Contamination P 3 N/A Input not required - water fraction of household pathway inactive water

Contamination P 3 D N/A Input not required - NR NR NR NR fraction of livestock drinking water/ingestion water pathways inactive

Contamination P 3 D N/A Input not required - plant NR NR NR NR fraction of irrigation ingestion pathway inactive water

Page 13 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values P 2 D 6.10E-01 (All ROCs except 75th percentile value the 5 ROCs listed for Contamination distribution below) fraction of aquatic food S 0 0.39 1.0 0.39 Triangular (Co-60, Eu-152, Eu-154, Mn-54, Nb-94) NUREG/CR-7267

Contamination P 3 D N/A Input not required - plant NR NR NR NR fraction of plant food ingestion pathway inactive

Contamination P 3 D N/A Input not required - meat NR NR NR NR fraction of meat ingestion pathway inactive

Contamination P 3 D N/A Input not required - milk NR NR NR NR fraction of milk ingestion pathway inactive

Ingestion, Non-Dietary

Livestock fodder M 3 D N/A Input not required - meat NR NR NR NR intake for meat (kg/d) ingestion pathway inactive

Livestock fodder M 3 D N/A Input not required - milk NR NR NR NR intake for milk (kg/d) ingestion pathway inactive

Livestock water M 3 D N/A Input not required - water NR NR NR NR intake for meat (L/d) ingestion pathway inactive

Livestock water M 3 D N/A Input not required - milk NR NR NR NR intake for milk (L/d) ingestion pathway inactive

Livestock soil intake M 3 D N/A Input not required - meat NR NR NR NR (kg/d) ingestion pathway inactive

Mass loading for P 3 D N/A Input not required - plant NR NR NR NR foliar deposition ingestion pathway inactive (g/m3)

Depth of soil mixing P 2 S Triangular NUREG/CR-7267 0 0.15 0.6 0.23 layer (m)

Depth of roots (m) P 1 S N/A Input not required - plant 0.3 4 1.85 ingestion pathway inactive

Drinking water P 3 D N/A Input not required - NR NR NR NR fraction from ground drinking water ingestion water pathway inactive

Household water P 3 N/A Input not required -

fraction from ground drinking water pathway water inactive

Page 14 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Livestock water P 3 D N/A Input not required - NR NR NR NR fraction from ground drinking water/meat water ingestion pathways inactive

Irrigation fraction P 3 D N/A Input not required - NR NR NR NR from ground water drinking water pathway inactive

Wet weight crop yield P 2 S N/A Input not required - plant 0.56 0.48 0.001 0.999 1.75 for Non-Leafy (kg/m2) ingestion pathway inactive

Wet weight crop yield P 3 D N/A Input not required - plant NR NR NR NR for Leafy (kg/m2) ingestion pathway inactive

Wet weight crop yield P 3 D N/A Input not required - meat NR NR NR NR for Fodder (kg/m2) ingestion pathway inactive

Growing Season for P 3 D N/A Input not required - plant NR NR NR NR Non-Leafy (y) ingestion pathway inactive

Growing Season for P 3 D N/A Input not required - plant NR NR NR NR Leafy (y) ingestion pathway inactive

Growing Season for P 3 D N/A Input not required - meat NR NR NR NR Fodder (y) ingestion pathway inactive

Translocation Factor P 3 D N/A Input not required - plant NR NR NR NR for Non-Leafy ingestion pathway inactive

Translocation Factor P 3 D N/A Input not required - plant NR NR NR NR for Leafy ingestion pathway inactive

Translocation Factor P 3 D N/A Input not required - meat NR NR NR NR for Fodder ingestion pathway inactive

Weathering Removal P 2 S N/A Input not required - plant 5.1 18 84 33 Constant for ingestion pathway inactive Vegetation (1/y)

Wet Foliar P 3 D N/A Input not required - plant NR NR NR NR Interception Fraction ingestion pathway inactive for Non-Leafy

Wet Foliar P 2 S N/A Input not required - plant 0.06 0.67 0.95 0.58 Interception Fraction ingestion pathway inactive for Leafy

Wet Foliar P 3 D N/A Input not required - meat NR NR NR NR Interception Fraction ingestion pathway inactive for Fodder

Page 15 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Dry Foliar P 3 D N/A Input not required - plant NR NR NR NR Interception Fraction ingestion pathway inactive for Non-Leafy

Dry Foliar P 3 D N/A Input not required - plant NR NR NR NR Interception Fraction ingestion pathway inactive for Leafy

Dry Foliar P 3 D N/A Input not required - meat NR NR NR NR Interception Fraction ingestion pathway inactive for Fodder

Storage times of contaminated foodstuffs (days)

Fruits, non-leafy B 3 D N/A Input not required - plant NR NR NR NR vegetables, and grain ingestion pathway inactive

Leafy vegetables B 3 D N/A Input not required - plant NR NR NR NR ingestion pathway inactive

Milk B 3 D N/A Input not required - milk NR NR NR NR ingestion pathway inactive

Meat and poultry B 3 D N/A Input not required - meat NR NR NR NR ingestion pathway inactive

Fish B 3 D 7 RESRAD Default NR NR NR NR

Crustacea and B 3 D 7 RESRAD Default NR NR NR NR mollusks

Well water B 3 D N/A Input not required - NR NR NR NR drinking water pathway inactive

Surface water B 3 D N/A Input not required drinking NR NR NR NR water pathway inactive

Livestock fodder B 3 D N/A Input not required - meat NR NR NR NR ingestion pathway inactive

Special Radionuclides (C-14)

C-12 concentration P 3 D 2.00E-05 RESRAD Default NR NR NR NR in water (g/cm3)

C-12 concentration P 3 D 3.00E-02 RESRAD Default NR NR NR NR in contaminated soil (g/g)

Fraction of P 3 D 2.00E-02 RESRAD Default NR NR NR NR vegetation carbon from soil

Page 16 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Fraction of P 3 D 9.80E-01 RESRAD Default NR NR NR NR vegetation carbon from air

C-14 evasion layer P 2 S Triangular NUREG/CR-7267 0.2 0.3 0.6 0.3 thickness in soil (m)

C-14 evasion flux P 3 D 7.00E-07 RESRAD Default NR NR NR NR rate from soil (1/s)

C-12 evasion flux P 3 D 1.00E-10 RESRAD Default NR NR NR NR rate from soil (1/s)

Fraction of grain in B 3 D 0.2500 NUREG/CR-7267 NR NR NR NR beef cattle feed

Fraction of grain in B 3 D 0.1000 NUREG/CR-7267 NR NR NR NR milk cow feed

Inhalation Dose Conversion Factors (mrem/pCi inhaled) from FGR11 (contained in RESRAD Dose Conversion Factor Library)

Ingestion Dose Conversion Factors (mrem/pCi ingested) from FGR11 (contained in RESRAD Dose Conversion Factor Library)

Plant Transfer Factors (pCi/g plant)/(pCi/g soil)

Note: Plant ingestion pathway closed - input for plant transfer factors not required for Industrial Use dose calculations.

Meat Transfer Factors (pCi/kg)/(pCi/d)

Note: Meat ingestion pathway closed - input for meat transfer factors not required for Industrial Use dose calculations.

Milk Transfer Factors (pCi/L)/(pCi/d)

Note: Milk ingestion pathway closed - input for milk transfer factors not required for Industrial Use dose calculations.

Bioaccumulation Factors for Fish ((pCi/kg)/(pCi/L))

Ac-227 P 2 S Lognormal-n NUREG/CR-7267 3.2 1.1 2.5E+01

Am-241 P 2 D 5.14E+02 75th percentile value

Am-243 P 2 S Lognormal-n NUREG/CR-7267 5.5 1.1 2.4E+02

C-14 P 2 D 9.28E+05 75th percentile value

Cm-243 P 2 S Lognormal-n NUREG/CR-7267 3.4 1.1 3.0E+01

Cm-244 P 2 S Lognormal-n NUREG/CR-7267 3.4 1.1 3.0E+01

Co-60 P 2 S Lognormal-n NUREG/CR-7267 4.3 0.9 7.4E+01

Cs-137 P 2 D 4.47E+03 75th percentile value

Eu-152 P 2 S Lognormal-n NUREG/CR-7267 4.9 1.6 1.3E+02

Page 17 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Eu-154 P 2 S Lognormal-n NUREG/CR-7267 4.9 1.6 1.3E+02

Fe-55 P 2 D 5.90E+02 75th percentile value

Gd-152 P 2 S Lognormal-n NUREG/CR-7267 3.4 1.1 3.0E+01

H-3 P 2 D 1.07E+00 75th percentile value

Mn-54 P 2 S Lognormal-n NUREG/CR-7267 5.5 1.9 2.4E+02

Nb-94 P 2 S Lognormal-n NUREG/CR-7267 5.7 1.1 3.0E+02

Ni-63 P 2 D 3.01E+01 75th percentile value

Np-237 P 2 D 4.21E+01 75th percentile value

Pa-231 P 2 S Lognormal-n NUREG/CR-7267 2.3 1.1 1.0E+01

Pb-210 P 2 S Lognormal-n NUREG/CR-7267 3.2 1.1 2.5E+02

Po-210 P 2 S Lognormal-n NUREG/CR-7267 3.6 1.5 3.7E+01

Pu-238 P 2 D 4.32E+04 75th percentile value

Pu-239 P 2 D 4.32E+04 75th percentile value

Pu-240 P 2 D 4.32E+04 75th percentile value

Pu-241 P 2 D 4.32E+04 75th percentile value

Ra-226 P 2 S Lognormal-n NUREG/CR-7267 1.4 1.9 4.1E+00

Ra-228 P 2 S Lognormal-n NUREG/CR-7267 1.4 1.9 4.1E+00

Sb-125 P 2 D 1.00E+02 75th percentile value

Sr-90 P 2 D 7.71E+00 75th percentile value

Tc-99 P 2 D 4.21E+01 75th percentile value

Te-12m P 2 S Lognormal-n NUREG/CR-7267 5.0 0.4 1.5E+02

Th-228 P 2 S Lognormal-n NUREG/CR-7267 4.6 1.1 9.9E+01

Th-229 P 2 S Lognormal-n NUREG/CR-7267 4.6 1.1 9.9E+01

Th-230 P 2 S Lognormal-n NUREG/CR-7267 4.6 1.1 9.9E+01

U-233 P 2 S Lognormal-n NUREG/CR-7267 0.0 2.5 1.0E+00

U-234 P 2 S Lognormal-n NUREG/CR-7267 0.0 2.5 1.0E+00

U-235 P 2 S Lognormal-n NUREG/CR-7267 0.0 2.5 1.0E+00

U-236 P 2 S Lognormal-n NUREG/CR-7267 0.0 2.5 1.0E+00

Page 18 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

BFM IR Scenario: Input Values for RESRAD-Onsite Code Executions to Support the Development of DCGLIR Values Bioaccumulation Factors for Crustacea/ Mollusks ((pCi/kg)/(pCi/L)) RESRAD default value for each radionuclide applied

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 17 RESRAD Default NR NR NR NR points for dose

Table 2 Notes:

a P = physical, B = behavioral, M = metabolic b 1 = high-priority parameter, 2 = medium-priority parameter, 3 = low-priority parameter c D = deterministic, S = stochastic N/A = not applicable

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 Triangular: 1 = minimum, 2 = mode, 3 = maximum Uniform: 1 = minimum, 2 = maximum In addition to the RESRAD-Onsite results, calculations of the ROC-specific DCGL values relied on 2 other calculations. The first is the calculation of the activity concentrations in fill material (pCi/g) that corresponded to surface activity concentrations equal to 1 pCi/m2. This was accomplished using the following equation:

Cfill = As/((Vfill x1E6xDfill)) Eq. 1 Where:

Cfill = activity concentration in the fill material (pCi/g) per surface area activity concentration = 1 pCi/m2 As = unit surface area activity concentration assumed over 1 m2 of concrete surface (1 pCi)

Vfill = unit volume of fill material (1 m3) 1E6 = conversion factor (cm3 per m3)

Dfill = density of fill material (g/cm3)

The mean value of the density distribution for sand (1.5105 g/cm3) was applied for all ROCs because this parameter was not identified as risk-sensitive for any ROC (refer to TSD 24-055).

Page 19 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Cfill = 1pCi/(1m3

  • 1E+06 cm3/m3
  • 1.5101g/cm3) = 6.62E-07 pCi/g per 1 pCi/m2

The other calculation is of ROC-specific DCGLIR values using RESRAD-Onsite POM doses, 10CFR20.1402 dose criterion, and fill activity concentration, 6.62E-07 pCi/g per 1 pCi/m2. This was accomplished using equation 2 below.

DCGLIR,ROC = [25 ÷ (POMROC x Cfill)] Eq. 2 Where:

DCGLIR,ROC = ROC-specific DCGLIR value (pCi/m2) 25 = 10CFR20.1402 unrestricted release criterion (mrem/y)

POMROC = ROC-specific POM dose (mrem/y per 1 pCi/g) calculated using RESRAD-Onsite 7.2 Cfill = 6.62E-07 pCi/g per pCi/m2

Column 2 of Table 3 provides the calculated POM dose for each ROC. Appendix A provides pages from the RESRAD-Onsite 7.2 output reports showing the calculated POM doses by ROC.

Column 3 of Table 3 provides ROC-specific DCGLIR values derived using equation 2. Input for equation 2 were the RESRAD-Onsite 7.2 POM doses (mrem/y per pCi/g), 10CFR20.1402 dose criterion (25 mrem/y), and the values of Cfill calculated in step 6.6 (6.62E-07 pCi/g per 1 pCi/m2 for all ROCs).

The DCGLIR,ROC values were calculated using Excel. The following hand calculations for Am-241 and H-3 confirmed the spreadsheet's operability.

DCGLIR for Am-241 = 25 mrem/y ÷ (1.42E-03 mrem/y per pCi/g

  • 6.62E -07 pCi/g per 1 pCi/m2) = 2.66E-10 pCi/m2. (Note: Difference at the last digit is due to rounding of decimal places retained in Excel spreadsheet.)

DCGLIR for H-3 = 25 mrem/y ÷ (1.94E-08 mrem/y per pCi/g

  • 6.62E-07 pCi/g per 1 pCi/m2) = 1.95E+15 pCi/m2.

Table 3: RESRAD-Onsite Generated POM Doses and DCGLIR Values by ROC

ROC POM dose DCGLIR (mrem/y) (pCi/m2 Am-241 1.42E-03 2.65E+10 C-14 5.20E-02 7.26E+08 Cm-243 1.58E-04 2.40E+11 Cm-244 3.89E-04 9.70E+10 Co-60 1.51E-04 2.50E+11 Cs-137 1.99E-04 1.90E+11 Eu-152 3.50E-05 1.08E+12 Eu-154 4.42E-05 8.55E+11 Fe-55 1.54E-07 2.46E+14 H-3 1.94E-08 1.95E+15 Mn-54 1.32E-05 2.87E+12 Nb-94 3.04E-02 1.24E+09

Page 20 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

ROC POM dose DCGLIR (mrem/y) (pCi/m2 Ni-63 1.29E-07 2.92E+14 Np-237 7.84E-03 4.82E+09 Pu-238 1.65E-01 2.29E+08 Pu-239 1.86E-01 2.03E+08 Pu-240 1.86E-01 2.03E+08 Pu-241 3.27E-03 1.15E+10 Sb-125 9.21E-06 4.10E+12 Sr-90 4.58E-05 8.24E+11 Tc-99 1.72E-05 2.19E+12 3.2 DCGLDS Calculations The drilling spoils scenario assumes that contaminated concrete is captured and mixed with the soil column extracted during the installation of a hypothetical onsite well. In this scenario, the source term is assumed to reside on the concrete surface, not in the soil column. The concrete-soil mixture constitutes the drilling spoils. Assuming the minimum distance to a basement floor maximizes the radionuclide concentration in the drilling spoils by minimizing the soil column. Of the concrete structures to remain in place at the OCNGS site, the Old Radwaste Building (ORB) has the shallowest floor, 14.4 ft (4.39m) [11]. The drill is assumed to travel 1 inch (0.0254 m) into the ORB floor before drilling is stopped due to meeting refusal from the concrete.

Therefore, the total well drilling depth is assumed to be 17.48 ft (5.33m), the sum of the ORB wall, 3-ft cover, and 1 inch into concrete before refusal. The drilling spoils brought to the surface are treated as soil and are assumed to be spread on the ground at a thickness of 6 inches (0.1524 m), which provides a conservative estimate for the contaminated zone area. The four exposure pathways for the IU scenario (listed in section

1) are assumed to be active for the drilling spoils.

The volume of the drilling spoils was calculated using the equation 3:

Vds = r2h Eq. 3

where Vds = the volume of drilling spoils (m3)

= pi constant r = radius of borehole (m) h = drilling depth (m)

Input for volume and area calculations:

  • The diameter of the bore hole = 8 inches (0.2032m).
  • Radius of bore hole = 4 inches (0.1016m)
  • Height of ORB wall = 14.4 ft (4.39m)
  • Cover thickness = 3 ft (0.91m)
  • Concrete depth to refusal = 1 inch (0.0254m)

Page 21 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

  • Density of fill material = 1.5105 g/cm3 (assumed sand; mean density value for sand distribution)
  • Thickness of CZ at the surface = 6 inches (0.1524m)

The area of the drilling spoils at the ground surface (Ads) was calculated by dividing the drilling spoils volume by the assumed thickness of the spoils after spreading :

Ads = Vds/Tds Eq. 4 where Vds = the volume of drilling spoils (m3)

Tds = assumed thickness of the drilling spoils at the ground surface (m)

Assuming a drill column depth = 5.33m as the h term, the volume (Vds) and area (Ads) of the drilling spoils are:

Vds = r2h = (3.1415927)(0.2032m/2)2(5.33m) = 0.1728m3 Ads = (0.1728m3)/(0.1524m) = 1.134 m2 The area concentration activity of contamination on the concrete, Cc (pCi/m2), required to produce a concentration in the drilling spoils equal to 1 pCi/g was determined using the following equation:

Cc = (Vds)(1x106)(Df)(Cds)/ r2 Eq. 5

Where Cc = area concentration activity of contamination on the concrete required to produce a concentration in the drilling spoils equal to 1 pCi/g Vds = the volume of drilling spoils (m3) 1x106 = conversion for cm3/m3 Df = density of fill material (g/cm3), assumed sand as above Cds = unit concentration in drilling spoils (1 pCi/g)

= pi constant r = radius of borehole (m)

Using equation 5, the area concentration activity of contamination on the concrete, Cc (pCi/m2), required to produce a concentration in the drilling spoils equal to 1 pCi/g:

Cc = (Vds)(1x106)(Df)(Cds)/ r2

= (0.1728m3)(1x106 cm3/m3)(1.5105 g/cm3)(1 pCi/g)/(3.1415297)(0.1016 m)2

= 8.05x106 pCi/m2 per 1 pCi/g

The drilling spoils ROC-specific DCGL values (DCGLds,ROC) were calculated as follows:

DCGLds,ROC = (25)(Cc)(AFdsA)/POMROC Eq. 6 where 25 = 10CFR20.1402 radiological criterion for unrestricted release (mrem/y)

Page 22 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Cc = area concentration activity of contamination on the concrete required to produce a concentration in the drilling spoils equal to 1 pCi/g, 8.05x106 pCi.m2 AFdsA = the area factor applicable to Ads (unitless) taken from Table 4 in ENG-OCS-009.

POMROC = the peak of the mean dose (mrem/y per pCi/g) taken from Table 4 in ENG-OCS-008.

The calculations for DCGLds,ROC were performed using an Excel spreadsheet. The following hand calculation for Am-241 and H-3 confirmed the operability of the spreadsheet.

DCGLds for Am-241 = (25 mrem/y)(8.05x106 pCi/m2 per 1 pCi/g)(12)/(0.0342 mrem/y per 1 pCi/g) = 7.06x1010 pCi/m2.

DCGLds for H-3 = (25 mrem/y)(8.05x106 pCi/m2 per 1 pCi/g)(45)/(0.000498 mrem/y per 1 pCi/g) = 1.82x1013 pCi/m2.

Table 4: RESRAD-Onsite Generated POM Doses, Area Factors, and DCGL ds Values by ROC

POM Dosea DCGLDS ROC (mrem/y per pCi/g) AF1mb (pCi/m2)

Am-241 3.42E-02 12 7.06E+10 C-14 1.21E-02 585 9.73E+12 Cm-243 1.38E-01 9 1.31E+10 Cm-244 1.37E-02 16 2.35E+11 Co-60 3.15E+00 9 5.75E+08 Cs-137 6.99E-01 9 2.59E+09 Eu-152 1.42E+00 9 1.28E+09 Eu-154 1.53E+00 9 1.18E+09 Fe-55 2.98E-06 278 1.88E+16 H-3 4.98E-04 45 1.82E+13 Mn-54 7.34E-01 9 2.47E+09 Nb-94 2.01E+00 9 9.01E+08 Ni-63 3.23E-06 176 1.10E+16 Np-237 4.35E-01 9 4.16E+09 Pu-238 2.20E-02 16 1.46E+11 Pu-239 8.17E-02 21 5.17E+10 Pu-240 8.57E-02 21 4.93E+10 Pu-241 1.00E-03 24 4.83E+12 Sb-125 4.50E-01 9 4.03E+09 Sr-90 5.89E-03 11 3.76E+11 Tc-99 1.82E-03 27 2.99E+12

aPOM dose value from Table 4 in ENG-OCS-008.

bAF value from Table 4 in ENG-OCS-009.

Page 23 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

3.3 DCGLEC Calculations This scenario assumes that portions of the concrete foundation walls of the building producing the largest concrete volume are excavated, rubblized, spread over the ground surface, and treated as surface soil with the application of the Industrial Use exposure pathways listed in section 6.1. The building walls (assumed 3 ft below grade to account for a cover of site soil) are excavated to the depth sites average depth to groundwater based on data from site groundwater monitoring wells located around the RB, ORB, and TB.

The excavated and rubblized concrete is assumed spread to a thickness of 1m over the ground surface.

Site groundwater data from monitoring wells close to the Reactor Building (RB), Turbine Building (TB), and ORB for 2020 - 2023 were used to determine the average depth of groundwater. Groundwater data are provided in Appendix B.

The dimensions for wall lengths and thicknesses for the RB, TB, and ORB were taken from Holltec-00045 Calc-001 and compared to determine the building foundation that would produce the largest volume of concrete if excavated to the average depth of groundwater. The building wall height accounting for 3-ft cover = depth to groundwater - 3 ft.

The volume of excavated concrete is calculated using the following equation:

Vec = (4-wall total length)(average depth to groundwater-3ft)(wall thickness) Eq. 7 Reactor Building:

4-wall total length = 592 ft Wall thickness = 3.5 ft Wall height = (14.5 ft - 3 ft) = 11.5 ft Vec = (592ft)(3.5ft)(11.5ft) = 23,830 ft3 (value rounded) = 675 m3(value rounded)

Turbine Building:

4-wall total length = 893 ft Wall thickness = 3.0 ft Wall height = (14.5 ft - 3 ft) = 11.5 ft Vec = (893ft)(3.0ft)(11.5ft) = 30,811 ft3 (value rounded) = 872 m3(value rounded)

Old Radwaste Building:

4-wall total length = 239 ft Wall thickness = 2.5 ft Wall height = (14.5 ft - 3 ft) = 11.5 ft Vec = (239ft)(2.5ft)(11.5ft) = 6,872 ft3 (value rounded) = 195 m3(value rounded)

The volume of the TB was selected as the most conservative input for the CZ area calculation.

The area of the CZ with a thickness of 1 m was calculated using the following equation:

Acz = Vec/Tcz Eq. 8 Where

Page 24 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Acz = the area of the CZ (m2)

Vec = the volume of excavated concrete (m3)

Tcz = assumed thickness of the CZ (1m)

Area of the CZ using the TB value for Vec : Acz = Vec/h = 872 m3/1m = 872 m2

The concentration activity in the excavated concrete (pCi/g) resulting from area contamination on the concrete equal to 1 pCi/m2 was determined using the following equation:

Cec = (Ac)/(tw)(30.48)(WUA)(1x104)(Dc) Eq. 9

Where Cec = unit concentration in the excavated concrete (pCi/g per 1 pCi/m2)

Ac = unit activity over 1 m2 of concrete surface (1 pCi) tw = wall thickness (ft) 30.48 = conversion for cm/ft WUA = unit area of concrete wall (1 m2) 1x104 = conversion for cm2/m2 Dc = assumed density of concrete, 2.3 g/cm2, which is the mid-point of the density range in the 1970 edition of the Radiological Health Handbook The calculated value for Cec is:

Cec = (Ac)/(tw)(30.48)(WUA)(1x104)(Dc)

= (1 pCi)/(3ft)(30.48)(1m2)(1x104)(2.3 g/cm3)

= 4.75x10-7 pCi/g per 1 pCi/m2

The excavated concrete ROC-specific DCGL values are calculated using Equation 10:

DCGLec,ROC = (DCGLsoil,ROC)(AFcz,ROC)/Cec Eq. 10 Where DCGLec,ROC = ROC-specific DCGLec (pCi/m2)

DCGLsoil,ROC = ROC-specific DCGL (pCi/g) (from ENG-OCS-008)

AFcz,ROC = the ROC-specific area factor applicable to Acz (unitless) (from ENG-OCS-009)

Cec = unit concentration in the excavated concrete (pCi/g per 1 pCi/m2)

The AF for a CZ area = 872 m2 falls between values listed for CZ areas equal to 500 m2 to 1000 m2 (Table 4 in ENG-OCS-009). Except for C-14 and Tc-99, the AF value = 1 for all other ROCs for a 1000 m2 CZ area. Rather

Page 25 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

than applying interpolated AF values, an AF value of 1 was applied to all ROCs to increase conservatism in the DCGLEC values. The application of an AF = 1 allows re-writing equation 10:

DCGLec,ROC = (DCGLsoil,ROC)/Cec Values for DCGLsoil,ROC were taken from Table 4 in ENG-OCS-008 and are provided in column 2 of Table 5.

The calculations for DCGLec,ROC were performed using an Excel spreadsheet. The following hand calculation for Am-241 and H-3 confirmed spreadsheet operability.

DCGLec for Am-241 = (7.30x102 pCi/g)/(4.75x10-7 pCi/g per pCi/m2) = 1.54x109 pCi/m2 (Note: Difference is due to rounding of decimal places retained in Excel spreadsheet.)

DCGLec for H-3 = (5.02x104 pCi/g)/(4.75x10-7 pCi/g per pCi/m2) = 1.06x1011 pCi/m2

Table 5: DCGLEC Values by ROC

DCGLsoil DCGLec ROC (pCi/g) (pCi/m2)

Am-241 7.31E+02 1.54E+09 C-14 2.07E+03 4.35E+09 Cm-243 1.81E+02 3.81E+08 Cm-244 1.82E+03 3.83E+09 Co-60 7.94E+00 1.67E+07 Cs-137 3.58E+01 7.53E+07 Eu-152 1.76E+01 3.70E+07 Eu-154 1.63E+01 3.43E+07 Fe-55 8.39E+06 1.76E+13 H-3 5.02E+04 1.06E+11 Mn-54 3.41E+01 7.17E+07 Nb-94 1.24E+01 2.61E+07 Ni-63 7.74E+06 1.63E+13 Np-237 5.75E+01 1.21E+08 Pu-238 1.14E+03 2.40E+09 Pu-239 3.06E+02 6.44E+08 Pu-240 2.92E+02 6.14E+08 Pu-241 2.50E+04 5.26E+10 Sb-125 5.56E+01 1.17E+08 Sr-90 4.24E+03 8.92E+09 Tc-99 1.37E+04 2.88E+10

Page 26 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

3.4 DCGLW/F Calculations DCGLw/f values were calculated using the following equation:

DCGLw/f = 1/(1/DCGLIR)+(1/DCGLDS)+(1/DCGLEC) Eq. 11 The values for DCGLW/F are provided by ROC in Table 6. The calculations for DCGLW/F were performed using an Excel spreadsheet. The following hand calculations for Am-241, Co-60, and H-3 confirmed the operability of the spreadsheet.

DCGLW/F for Am-241 = 1/(1/2.65E+10)+(1/6.96E+11)+(1/1.54E+09) = 1.45E+09 pCi/m2.

DCGLW/F for Co-60 = 1/(1/2.50E+11)+(1/5.67E+09)+(1/1.67E+07) = 1.66E+07 pCi/m2.

DCGLW/F for H-3 = 1/(1/1.95E+15)+(1/1.79E+14)+(1.06E+11) = 1.06E+11 pCi/m2.

Table 6: DCGLW/F Values by ROC

DCGLIR DCGLDS DCGLEC DCGLW/F ROC (pCi/m2) (pCi/m2) (pCi/m2) (pCi/m2)

Am-241 2.65E+10 7.06E+10 1.54E+09 1.42E+09 C-14 7.26E+08 9.73E+12 4.35E+09 6.22E+08 Cm-243 2.40E+11 1.31E+10 3.81E+08 3.69E+08 Cm-244 9.70E+10 2.35E+11 3.83E+09 3.63E+09 Co-60 2.50E+11 5.75E+08 1.67E+07 1.62E+07 Cs-137 1.90E+11 2.59E+09 7.53E+07 7.31E+07 Eu-152 1.08E+12 1.28E+09 3.70E+07 3.60E+07 Eu-154 8.55E+11 1.18E+09 3.43E+07 3.33E+07 Fe-55 2.46E+14 1.88E+16 1.76E+13 1.64E+13 H-3 1.95E+15 1.82E+13 1.06E+11 1.05E+11 Mn-54 2.87E+12 2.47E+09 7.17E+07 6.97E+07 Nb-94 1.24E+09 9.01E+08 2.61E+07 2.48E+07 Ni-63 2.92E+14 1.10E+16 1.63E+13 1.54E+13 Np-237 4.82E+09 4.16E+09 1.21E+08 1.15E+08 Pu-238 2.29E+08 1.46E+11 2.40E+09 2.09E+08 Pu-239 2.03E+08 5.17E+10 6.44E+08 1.54E+08 Pu-240 2.03E+08 4.93E+10 6.14E+08 1.52E+08 Pu-241 1.15E+10 4.83E+12 5.26E+10 9.45E+09 Sb-125 4.10E+12 4.03E+09 1.17E+08 1.14E+08 Sr-90 8.24E+11 3.76E+11 8.92E+09 8.62E+09 Tc-99 2.19E+12 2.99E+12 2.88E+10 2.82E+10

Page 27 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

4 References

1. TSD 24-055, Basement Fill Model: Probabilistic Analysis for the Instantaneous Release Scenario Assuming Industrial Use Exposure Pathways.
2. ENG-OCS-008, Derived Concentration Guideline Levels Values for Soil - Industrial Use Scenario Oyster Creek Station
3. ENG-OCS-009, Area Factors for Soil - Industrial Use Scenario
4. Radionuclide Selection for DCGL Development-Oyster Creek Station Site Characterization Project, January 2022
5. NUREG/CR-7267, Default Parameter Values and Distribution in RESRAD-ONSITE V7.2, RESRAD-BUILD V3.5, and RESRAD-OFFSITE V4.0 Computer Codes, February 2020
6. ANL/EVS/TM-18/1, RESRAD-Onsite 7.2 Users Guide, April 2018
7. NUREG/CR-5512, Volume 3, Residual Radioactive Contamination from Decommissioning:

Parameter Analysis, Draft Report for Comment, October 1999

8. Hydrogeologic Investigation Report, GHD, January 2017
9. Oyster Creek Station Historical Site Assessment, Rev. 2, November 2021
10. Health Physics, Vol. 39, Regional and Site-Specific Absolute Humidity Data for Use in Tritium Dose Calculations, 1980
11. Holtec-00045 Calc-001, Oyster Creek Generating Station Assessment of Subsurface Structures

Page 28 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Appendix A

IR Scenario: Peak of the Mean Dose by ROC

Page 29 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Am-241 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/30/2024 18:18 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Am241 File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_AM241_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 2.894E+00 1.424E-03

C-14 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/28/2024 15:03 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_C14_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_C14_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 5.201E-02

Cm-243 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/02/2024 13:42 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Cm243_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_CM243_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 7.017E+01 1.575E-04

Cm-244 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/02/2024 09:38 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Cm244_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_CM244_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 5.380E+01 3.892E-04

Co-60 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/28/2024 15:19 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Co60_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_CO60_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 1.512E-04

Cs-137 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/28/2024 15:36 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Cs137_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_CS137_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.304E+00 1.985E-04

Page 30 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Eu-152 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 14:27 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Eu152_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_EU152_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 3.495E-05

Eu-154 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 09:40 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Eu154_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_EU154_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 4.415E-05

Fe-55 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 14:37 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Fe55_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_FE55_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.304E+00 1.536E-07

H-3 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 14:44 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_H3_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_H3_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 1.937E-08

Mn-54 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 10:30 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_Mn54_DCGL File : C:\\USERS\\WCPARISH\\ONEDRIVE - RADIATION SAFETY AND CONTROL SERVICES\\DOCUMENTS\\RESRAD CASE RUNS\\BFM-IU_MN54_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 1.316E-05

Nb-94 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/28/2024 12:36 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Nb94 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\NB94\\BFM-IU_DCGL_NB94.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.000E+03 3.039E-02

Page 31 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Ni-63 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/28/2024 13:03 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Ni63 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\NI63\\BFM-IU_NI63_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.000E+00 1.292E-07

Np-237 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/28/2024 13:29 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Np237 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\NP237\\BFM-IU_NP237.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 7.835E-03

Pu-238 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 08:42 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Pu238 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\PU238\\BFM-IU_PU238_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.304E+00 1.651E-01

Pu-239 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/01/2024 00:11 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Pu239 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\PU239\\BFM-IU_DCGL_PU239.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.701E+00 1.857E-01

Pu-240 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/03/2024 09:20 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Pu240 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\PU 240\\BFM-IU_DCGL_PU240.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.701E+00 1.857E-01

Pu-241 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 07/03/2024 11:53 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Pu241 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\PU241\\BFM-IU_DCGL_PU241.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 1.304E+00 3.270E-03

Page 32 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Sb-125 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/29/2024 06:40 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Sb125 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\SB125\\BFM-IU_DCGLSB125.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 9.212E-06

Sr-90 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/29/2024 06:30 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Sr90 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\SR90\\BFM-IU_DCGL_SR90.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 4.583E-05

Tc-99 Results:

RESRAD-ONSITE, Version 7.2 T<< Limit = 30 days 06/29/2024 06:57 Page 20 Probabilistic results summary : OCS BFM_Industrial Use_IR_DCGL_Tc99 File : C:\\RESRAD_FAMILY\\ONSITE\\7.2\\USERFILES\\TC99\\BFM-IU_TC99_DCGL.RAD Peak of the mean dose (averaged over observations) at graphical times Repetition Time of peak mean dose Peak mean dose Years mrem/yr 1 0.000E+00 1.724E-05

Page 33 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Appendix B OCNGS Site Groundwater Information

Page 34 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 7/26/2021 8.05 10/24/2022 8.21 1/27/2020 8.82 4/25/2022 8.92 MW-15K-1A 5/19/2020 8.97 West of TB 8.9 5/3/2021 9.05 10/18/2021 9.34 8/17/2020 9.53 4/18/2023 9.61 7/26/2021 16.60 10/24/2022 16.75 10/18/2021 16.85 1/27/2020 17.00 MW-16D 5/3/2021 17.03 North side of RB 17.0 4/24/2023 17.11 8/17/2020 17.18 5/19/2020 17.26 4/25/2022 17.43 7/26/2021 14.55 5/3/2021 14.92 5/19/2020 15.10 1/27/2020 15.20 MW-1A -2A 10/18/2021 15.31 South of ORB 15.5 10/24/2022 15.42 4/25/2022 15.92 8/17/2020 16.24 10/12/2020 16.55 7/26/2021 10.82 5/3/2021 11.11 5/19/2020 11.46 1/27/2020 11.67 MW-1I-1A 10/24/2022 11.71 North of TB 11.8 10/18/2021 11.85 4/25/2022 12.28 4/24/2023 12.32 8/17/2020 12.58 10/12/2020 12.62 MW-1I-2A 7/26/2021 11.30 North of TB 12.3 5/3/2021 11.65

Page 35 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/24/2022 12.03 5/19/2020 12.11 1/27/2020 12.25 10/18/2021 12.35 4/25/2022 12.68 4/20/2023 12.70 8/17/2020 13.04 10/12/2020 13.23 5/3/2023 10.16 5/3/2021 10.58 10/24/2022 10.62 1/27/2020 10.67 4/25/2022 10.70 MW-24-3A Farm 5/19/2020 10.90 Not considered - REMP control 2/8/2021 10.94 10/18/2021 11.00 1/27/2020 11.24 10/12/2020 11.54 10/12/2020 9.80 8/17/2020 10.20 10/24/2022 10.59 10/18/2021 10.64 MW -52 5/3/2021 10.65 Not considered - too far west 1/27/2020 10.68 4/20/2023 10.80 4/25/2022 10.81 5/19/2020 10.96 10/24/2022 10.17 4/25/2022 10.70 1/27/2020 10.71 5/3/2021 10.85 MW-53 5/19/2020 10.90 West of TB 10.9 10/12/2020 11.05 10/18/2021 11.20 4/18/2023 11.30 8/17/2020 11.34 10/12/2020 5.53 MW -54 1/27/2020 7.00 Not considered - too far west 8/17/2020 7.25

Page 36 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/24/2022 7.54 10/18/2021 7.75 4/25/2022 7.80 5/3/2021 7.82 4/20/2023 8.11 5/19/2020 8.20 10/12/2020 9.86 8/17/2020 10.25 10/24/2022 10.42 7/26/2021 10.43 MW-55 1/27/2020 10.61 West of TB 10.6 10/18/2021 10.80 4/18/2022 10.85 4/25/2022 10.90 5/3/2021 10.93 5/19/2020 11.25 10/24/2022 10.65 8/17/2020 10.68 7/26/2021 10.91 1/27/2020 11.02 MW-56I 10/18/2021 11.10 West of TB 11.1 10/12/2020 11.11 4/18/2023 11.15 5/3/2021 11.45 4/25/2022 11.60 5/19/2020 11.65 10/12/2020 10.10 8/17/2020 10.45 10/24/2022 10.75 10/18/2021 10.92 4/20/2023 10.95 MW -57I 7/26/2021 11.03 Not considered - too far west 5/19/2020 11.08 5/3/2021 11.10 1/27/2020 11.20 4/25/2022 11.23 10/12/2020 12.47 MW -59I 10/24/2022 12.79 West of TB 13.1 8/17/2020 12.90

Page 37 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 7/26/2021 13.15 10/18/2021 13.15 4/18/2023 13.15 1/27/2020 13.30 5/3/2021 13.40 5/19/2020 13.42 4/25/2022 13.47 10/24/2022 10.37 10/12/2020 10.43 8/17/2020 10.45 4/18/2023 10.60 MW-61I 1/27/2020 10.84 West of TB 10.9 4/25/2022 10.95 10/18/2021 11.05 7/26/2021 11.10 5/3/2021 11.30 5/19/2020 11.47 10/18/2021 11.65 10/12/2020 12.82 7/26/2021 12.90 1/27/2020 13.17 MW-62 8/17/2020 13.36 North of TB 13.3 5/19/2020 13.51 10/24/2022 13.56 5/3/2021 13.75 4/25/2022 13.98 4/24/2023 14.41 10/12/2020 9.85 8/17/2020 10.43 10/24/2022 10.62 7/26/2021 10.65 MW-64 10/18/2021 10.80 Not considered - too far west 5/3/2021 11.00 4/20/2023 11.02 1/27/2020 11.06 4/25/2022 11.15 5/19/2020 11.30 MW-65 5/19/2020 11.51 West of TB 12.2 10/24/2022 11.64

Page 38 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/12/2020 11.90 8/17/2020 12.05 7/26/2021 12.13 10/18/2021 12.27 4/18/2023 12.41 5/3/2021 12.45 4/25/2022 12.53 1/27/2020 12.68 10/24/2022 18.22 7/26/2021 18.30 5/19/2020 18.44 4/24/2023 18.47 MW-67 8/17/2020 18.59 inside TB footprint 18.6 1/27/2020 18.68 4/25/2022 18.78 10/18/2021 18.85 5/3/2021 18.87 10/12/2020 19.03 MW-68I 8/17/2020 17.25 South of RB 17.4 10/12/2020 17.51 7/26/2021 15.62 10/24/2022 15.64 1/27/2020 16.03 10/18/2021 16.05 MW-71 5/3/2021 16.10 South of RB 16.2 5/19/2020 16.35 8/17/2020 16.40 4/24/2023 16.43 4/25/2022 16.61 10/12/2020 16.81 10/24/2022 17.92 7/26/2021 17.94 1/27/2020 17.98 10/18/2021 18.03 MW -72 8/17/2020 18.05 North of RB 18.2 5/3/2021 18.20 4/24/2023 18.21 5/19/2020 18.30 4/25/2022 18.42

Page 39 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/12/2020 18.50 7/26/2021 17.57 8/17/2020 17.61 1/27/2020 17.64 4/24/2023 17.75 W-10 10/24/2022 17.79 South of RB 17.8 10/18/2021 17.80 10/12/2020 17.88 5/3/2021 17.90 4/25/2022 18.09 5/19/2020 18.15 7/26/2021 13.20 4/25/2022 13.52 5/3/2021 13.60 10/24/2022 13.76 W-12 10/18/2021 13.80 North of RB 13.9 5/19/2020 13.85 1/27/2020 13.90 4/24/2023 14.20 8/17/2020 14.45 10/12/2020 14.85 10/24/2022 19.02 8/17/2020 19.10 7/26/2021 19.22 1/27/2020 19.26 W-13 10/18/2021 19.37 North of RB 19.5 4/24/2023 19.47 4/25/2022 19.48 10/12/2020 19.52 5/19/2020 19.73 5/3/2021 20.65 10/24/2022 17.70 8/17/2020 17.90 7/26/2021 17.95 1/27/2020 17.96 NW of ORB 17.3 4/24/2023 18.11 10/18/2021 18.12 5/3/2021 18.30 4/25/2022 18.31

Page 40 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg)

W-14 W-14 W-14 W-14 W-14 W-14 W-14 W-14 W-14 5/19/2020 18.45 W-15 7/26/2021 10.35 W-15 5/3/2021 10.60 W-15 1/27/2020 10.87 W-15 10/18/2021 11.13 W-15 4/25/2022 11.37 NW of ORB 11.4 W-15 10/24/2022 11.41 W-15 5/19/2020 11.80 W-15 4/24/2023 12.01 W-15 8/17/2020 12.07 W-15 10/12/2020 12.45 W-16 7/26/2021 8.07 W-16 5/3/2021 8.33 W-16 5/19/2020 8.53 W-16 1/27/2020 8.65 W-16 10/18/2021 8.87 W-16 10/24/2022 9.00 Not considered - too far north W-16 4/25/2022 9.17 W-16 4/24/2023 9.23 W-16 8/17/2020 9.71 W-16 10/12/2020 10.30 8/17/2020 19.25 10/24/2022 19.29 1/27/2020 19.62 10/18/2021 19.72 W-1A 10/12/2020 19.75 Not considered - outside PA 4/24/2023 20.09 4/25/2022 20.34 5/3/2021 20.46 5/19/2020 20.56 W-24 7/26/2021 12.58 South of TB 13.7

Page 41 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/24/2022 12.72 5/3/2021 13.12 1/27/2020 13.30 5/19/2020 13.50 10/18/2021 13.73 4/25/2022 14.27 10/12/2020 14.65 8/17/2020 14.75 4/24/2023 14.77 7/26/2021 14.25 10/18/2021 14.35 10/24/2022 14.56 5/3/2021 15.26 W-3 4/20/2023 15.58 West of TB 15.4 4/25/2022 15.83 10/12/2020 15.86 1/27/2020 15.95 5/19/2020 16.08 8/17/2020 16.25 10/24/2022 17.56 7/26/2021 17.73 10/12/2020 17.76 10/18/2021 17.98 W-34 8/17/2020 18.00 South of TB 18.0 1/27/2020 18.10 5/3/2021 18.15 4/24/2023 18.16 4/25/2022 18.34 5/19/2020 18.35 8/17/2020 16.20 7/26/2021 16.45 1/27/2020 16.50 10/12/2020 16.52 W-4 10/18/2021 16.56 West of TB 16.7 10/24/2022 16.62 4/20/2023 16.65 4/25/2022 16.92 5/3/2021 17.02 5/19/2020 17.15

Page 42 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/24/2022 12.40 1/27/2020 12.51 1/27/2020 12.52 2/8/2021 12.55 10/18/2021 12.70 W-4A 4/24/2023 12.70 Not considered - too far SE 10/12/2020 12.71 5/3/2021 12.76 4/25/2022 12.81 5/19/2020 12.98 7/26/2021 11.61 5/3/2021 12.15 10/24/2022 12.27 5/19/2020 12.30 1/27/2020 12.35 W -5 10/18/2021 12.75 Not considered - too far NW 4/25/2022 12.82 4/24/2023 13.00 10/12/2020 13.05 8/17/2020 13.10 8/17/2020 19.64 7/26/2021 19.95 10/12/2020 20.03 1/27/2020 20.05 4/24/2023 20.08 W -6 10/18/2021 20.15 Not considered - too far NW 10/24/2022 20.20 4/25/2022 20.36 5/3/2021 20.55 5/19/2020 20.60 10/24/2022 14.34 7/26/2021 14.45 5/3/2021 14.91 1/27/2020 15.03 W -9 10/18/2021 15.05 South of RB 15.2 5/19/2020 15.15 4/25/2022 15.58 4/24/2023 15.66 8/17/2020 15.70

Page 43 Basement Fill Model: Calculation of DCGLW/F Values RSCS TSD 24-063 Assuming Industrial Use Exposure Pathways Revision 0

Average Well Date DTW General Location Depth (fbg) 10/12/2020 16.00 Average for wells near TB, RB, 14.5 Average All 13.89 and ORB

Page 44

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