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All sourcesNASA NTRSDOE OSTI
DOE OSTI2020

Modeling Aerial Gamma-Ray Backgrounds Using Non-negative Matrix Factorization

Airborne gamma-ray surveys are useful for many applications, ranging from geology and mining to public health and nuclear security. In all these contexts, the ability to decompose a measured spectrum into a linear combination of background source terms can provide useful insights into the data and lead to improvements in the techniques that use spectral energy windows. Multiple methods for the linear decomposition of spectra exist but are subject to various drawbacks, such as allowing negative photon fluxes or requiring detailed Monte Carlo modeling. In this work, we propose using non-negative matrix factorization (NMF) as a data-driven approach to spectral decomposition. Using aerial surveys that include flights over water, we demonstrate that the mathematical approach of NMF finds physically relevant structure in the aerial gamma-ray background, namely, that measured spectra can be expressed as the sum of nearby terrestrial emission, distant terrestrial emission, and radon and cosmic emission. Furthermore, these NMF background components are compared with the background components obtained by noise-adjusted singular value decomposition (NASVD), which contain negative photon fluxes and, thus, do not represent the emission spectra in as straightforward a way. Finally, we comment on the potential areas of research that are enabled by NMF decompositions, such as new approaches to spectral anomaly detection and data fusion.

73 NUCLEAR PHYSICS AND RADIATION PHYSICS↗
DOE OSTI2020

2019 LANL Radionuclide Air Emissions Report

In June 2020, Los Alamos National Laboratory (LANL) submitted letter ESHQSS: 20-025 to Region 6 of the Unites States Environmental Protection Agency (EPA). This letter transmitted the 2019 LANL Radionuclide Air Emissions Report to the EPA. This report summarizes LANL operations, air emissions of radionuclides, and subsequent off-site dose consequence from these emissions for calendar year 2019. This report is issued to meet requirements of 40 CFR 61 Subpart H, National Emission Standards for Emissions of Radionuclides other than Radon from Department of Energy Facilities. This regulation, called the Radionuclide NESHAP, establishes a limit of 10 millirem per year to the maximally exposed member of the public and requires an annual report to be submitted to the appropriate EPA Region by June 30th of each year. LANL’s off-site dose from airborne emissions of radionuclides in 2019 was 0.43 millirem. The normal practice is to issue this report directly to EPA Region 6 in June of each year, and then after the report is accepted by the EPA, re-issue the report for inclusion in the LANL Electronic Public Reading Room (EPRR). This second part is usually done in July of each year, but this step was overlooked in July 2020 due to other commitments. We regret this error. This omission was noted in late 2020; we are submitting the 2019 LANL Radionuclide Air Emissions Report to the EPRR now in December 2020. Aside from the addition of this cover sheet explaining the delay, the report is unchanged from the version submitted to EPA Region 6 in June.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

System Model Calculations for the Active Trenches of the Low-Level Burial Grounds, Hanford Site, Washington

Two lined trenches (Trench 31 and 34) located within the 200 West Low-Level Burial Ground (LLBG) area of the U.S. Department of Energy’s (DOE) Hanford Site are designated for permanent disposal of low-level radioactive waste (LLW) and mixed low-level radioactive waste (MLLW). In accordance with DOE O 435.1, Radioactive Waste Management, radioactive waste shall be managed and disposed in a manner that is protective of worker, public health and safety, and the environment. DOE O 435.1 requires a site-specific radiological performance assessment (PA) that includes calculations of potential releases and subsequent doses to members of the public for a period of 1,000 years after closure of a low-level waste (LLW) disposal facility. The purpose of this environmental calculation file (ECF) is to document the various dose calculations performed to support DOE’s LLBG PA. The dose assessments are performed to evaluate the potential exposure of an all-pathway representative person to radionuclide contaminants of potential concern (COPCs) that may be released from the LLBG Trenches 31 and 34 to the point of calculation (POC) located at the outer edge of a 100 m buffer zone surrounding the trench boundary. This ECF uses inputs from other ECFs and their associated model package reports (MPRs) supporting the LLBG PA. The five major objectives of this ECF are to present the results of the following: (1) Deterministic dose assessments for both groundwater and atmospheric exposure scenarios; (2) Radon-222 (Rn-222) flux emanating at the surface from the disposed wastes; (3) Uncertainty analyses of the groundwater pathway annual dose due to uncertainty in input parameters; (4) Sensitivity analyses of the input parameters that could potentially impact the fate and transport of the contaminants and doses; (5) Doses arising from inadvertent intruder exposure scenarios.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Update of Erosion Conditions and Assessment of Mitigation Options for the L-Bar Site

The L-Bar former uranium milling site was remediated and closed per regulations and is now under the long-term stewardship of the U.S. Department of Energy, Office of Legacy Management (DOE/LM). Since assuming stewardship in 2004, DOE/LM has observed erosion and sedimentation processes at the L-Bar Site that will challenge meeting the design closure criteria in the long term, and therefore erosion control structures were installed in several areas. Portions of these structures were subsequently damaged by summer convective storm events and they are being redesigned. At the request of DOE/LM, Desert Research Institute (DRI) reviewed the proposed redesign plans of the erosion control structures. The purpose of this review is to support DOE/LM decisions regarding mitigation of ongoing erosion processes, including assessing possible repair of the existing erosion control structures, as well as plan for effective long-term site management. This design review is performed in reference to the Uranium Mill Tailings Radiation Control Act (UMTRCA) standards contained in 40 CFR 192.02 that require containment of residual radioactive material be effective for up to 1,000 years (if achievable, but certainly for 200 years), limit radon release, protect groundwater, and minimize future maintenance. The erosion control structures under review are not subject to the UMTRCA standard directly, but they contribute to the performance of the overall containment system by virtue of their relationship with the large diversion channels bounding the disposal cell. The 11 design drawings included in “Erosion Control Alternatives Analysis, L-Bar, New Mexico, Disposal Site, LTS-111-0043-08-002,” dated January 11, 2019, and listed in Appendix A, and supporting calculations in Weston (2019) are the focus of the review. Additionally, DOE/LM provided supporting data such as a 2018 photogrammetry-based digital elevation model of the site, precipitation records collected from an on-site weather station, and sedimentation records collected at an on-site basin. This assessment includes review of the proposed design to mitigate current site conditions but also addresses site changes between the initial erosion assessment report (Miller et al., 2012) and current conditions. The analysis is at a predesign engineering level and does not include development of hydraulic or sediment transport models. Site precipitation data are included in Miller et al. (2012). The natural conditions of the site, the design of site diversion systems, observed erosion at the site, and predesign engineering analysis are used to develop a holistic view of the challenges to L-Bar Site stability and possible responsive actions.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Oak Ridge National Laboratory EPA Approval Letters and Historical Documentation for a Modification in Applying 40 CFR Part 61 Appendix D

Appendix D of Title 40 Part 61, “Methods for Estimating Radionuclide Emissions,” of the Code of Federal Regulations (CFR) provides a procedure that US Department of Energy (DOE) facility owners and operators can use to estimate radionuclide emissions to the atmosphere for dose calculations instead of measuring emissions for minor sources under 40 CFR Part 61, Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities.” The procedure assumes that any radioactive material heated above 100°C is completely vaporized and emitted to the atmosphere. In 1991, the DOE Oak Ridge Reservation (DOE-ORR) requested approval to use different release fractions (RFs) for uranium because of its high melting and boiling points (1,132°C and 3,818°C, respectively). In response to the request, Environmental Protection Agency (EPA) Region IV approved the use of modified RFs for elemental uranium provided no reaction had taken place to alter its chemical form. In 2015, DOE-ORR requested approval to use different RFs for radioactive tungsten, also because of its high melting and boiling points (3,410°C and 5,660°C, respectively). EPA Region IV approved the use of modified RFs for heated radioactive tungsten metal. In accordance with the two precedents set for heating uranium and radioactive tungsten metals, in 2016, DOE-ORR requested approval to use modified RFs in similar fashion for other radioactive solid metals and compounds with melting and boiling points above 500°C that might be heated above 100°C in future research projects and experiments, and again, the EPA Region IV granted approval to use modified RFs for the list of compounds. This document contains the EPA approval letters and historical documentation used in the process to obtain approval for the use of alternative Appendix D emission factors. The approval to DOE-ORR allows modifying the existing regulatory RFs to 1 when radioactive solid metals and compounds are heated to temperatures greater than or equal to the boiling point of the solid, to 10 -3 when radioactive solid metals and compounds are heated to temperatures greater than or equal to 90% of the melting point and less than the boiling point of the solid, and to 10 -6 when radioactive solid materials are heated to temperatures above ambient air temperature but below 90% of the melting point of the solid.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

A summary of air sampler filter performance data: Bladewerx Speclon 5(TM) and Millipore FMLW047 5um

Bladewerx™ LLC (Rio Rancho, NM) manufactures instrumentation, neutron shielding and activation foils for the radiation protection industry. Specializing in portable alpha/beta air monitors and sample counters, Bladewerx is the source of Speclon 5™ PTFE filter media that they recommend for high-resolution alpha spectroscopy. Los Alamos National Laboratory (LANL) utilizes Speclon™ filter material in CAM (Continuous Air Monitor) samplers for workplace air monitoring. Millipore FMLW (5μm) filters are also used at Los Alamos, and a comparison of the two filter types has been requested. For filter face air velocities from 0.066 m/s to 1.5 m/s, the aerosol collection efficiency (for 0.3 μm particle diameters) and the filter pressure drops were measured. The FWHM (full width half maximum) of alpha spectroscopy peaks was also determined, using naturally occurring radon progeny at an alpha energy of 6 MeV.

61 RADIATION PROTECTION AND DOSIMETRY↗
DOE OSTI2022

Idaho National Laboratory CY 2021 National Emission Standards for Hazardous Air Pollutants Analysis, Methodology and Results for Radionuclides

This report details calculations of potential dose at public receptor locations surrounding the Idaho National Laboratory (INL) Site boundary, and INL in-town facilities, from radionuclides reported to be in use and potentially emitted from INL facilities during calendar year (CY) 2021. All calculations were performed in accordance with the requirements in Code of Federal Regulations (CFR), Title 40, “Protection of the Environment,” Part 61, “National Emission Standards for Hazardous Air Pollutants (NESHAPs),” Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” (40 CFR 61, Subpart H). Modeling methodology, model input parameters, and contribution to dose by facility, source, and radionuclide at the maximally exposed individual (MEI) location are also discussed. The information in this report supports the “National Emission Standards for Hazardous Air Pollutants - Calendar Year 2021 INL Report for Radionuclides” (INL 2022). In CY 2021, the estimated annual potential dose at the INL Site MEI location was 6.67E-02 mrem/yr, up slightly from the previous year, but far less than the regulatory standard of 10 mrem/yr (CFR 40 Part 61, Subpart H). Approximately 97% of the total dose to the INL Site MEI originated from MFC sources. Emissions from INL in-town facilities resulted in an estimated annual potential dose of 6.21E-03 mrem/yr to the MEI, down 40% from the CY 2020 estimated dose. Year-to-year variations in estimated annual dose can be attributed to adjustments in laboratory operations, changes to facility infrastructure, and variation in meteorological conditions.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2022

Summary of Analytical Services for the Hanford Site Radionuclide NESHAP Program

This document serves as a summary of the analytical requirements used to demonstrate compliance on the Department of Energy (DOE) Hanford Site to 40 CFR 61, “National Emission Standards for Hazardous Air Pollutants,” (NESHAP) Subpart H, “National Emission Standards for Emissions of Radionuclides Other Than Radon From Department of Energy Facilities,” and WAC 246-247, “Radiation Protection – Air Emissions.” This document is a reference summarizing information from multiple existing requirement source documents and does not create, supersede, replace or over-ride any existing contractual, DOE, federal, state, permit or license requirement. The requirement source documents govern where any differences may exist.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

Flange Tritium Waste Containers Operational Concerns: How to Address the Issues Through the Venting Design

As a part of the U.S. Department of Energy (DOE), Los Alamos National Laboratory (LANL or Laboratory) must comply with regulations in the Clean Air Act (CAA) put forth in 40 Code of Federal Regulations (CFR) 61, Subpart H “National Emission Standards for Emissions of Radionuclides Other Than Radon from Department of Energy Facilities.” The standard states, “Emissions of radionuclides to the ambient air from Department of Energy facilities shall not exceed those amounts that would cause any member of the public to receive in any year an effective dose equivalent of 10 mrem/yr [millirem per year] [1].” This regulation is referred to as the National Emission Standards for Hazardous Air Pollutants for Radionuclides (Radionuclide NESHAP or Rad-NESHAP).

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2021

Post-Closure Report for Closed Resource Conservation and Recovery Act Corrective Action Units, Nevada National Security Site, Nevada: For Calendar Year 2020 (Rev. 2)

This report serves as the combined annual report for post-closure activities in compliance with the requirements listed in Resource Conservation and Recovery Act (RCRA) Permit Number NEV HW0101 associated with the following closed corrective action units (CAUs): 1) CAU 90, Area 2 Bitcutter Containment; 2) CAU 91, Area 3 U-3fi Injection Well; 3) CAU 92, Area 6 Decon Pond Facility; 4) CAU 110, Area 3 WMD U-3ax/bl Crater; 5) CAU 111, Area 5 WMD Retired Mixed Waste Pits; 6) CAU 112, Area 23 Hazardous Waste Trenches The locations of the sites are shown in Figure ES-1. This report covers calendar year 2020. The post-closure requirements for these sites are described in RCRA Permit NEV HW0101 and are summarized in each CAU-specific section of this report. The results of the inspections, a summary of maintenance activities, and an evaluation of monitoring data are presented in this report. Site inspections are conducted annually at CAUs 90, 91, and 112; semiannually at CAUs 92 and 110; and quarterly at CAU 111. Additional inspections are conducted at CAUs 92 and 111 if precipitation occurs in excess of 1.0 inch in a 24-hour period. Inspections include an evaluation of the condition of the units, including covers, fences, signs, gates, and locks. At CAUs 110 and 111, soil moisture monitoring and subsidence surveys are conducted in addition to the visual inspections. At CAU 110, the site fence, gate, lock, and use restriction signs are evaluated. At CAU 111, an ecological survey, direct radiation monitoring, air monitoring, radon flux monitoring, and groundwater monitoring are also conducted. This report will address all monitoring item notes above except groundwater monitoring. Groundwater monitoring is documented in the Nevada National Security Site Data Report: Groundwater Monitoring Program Area 5 Radioactive Waste Management Site. All required inspections, maintenance, and monitoring were conducted in accordance with the post-closure requirements of the permit. Revision 6 of RCRA Permit NEV HW0101 was issued effective December 10, 2015, and remained in effect until December 10, 2020. At the time of this report submittal, the new RCRA permit application was in review.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2022

An LSTM Deep Learning Network for ¿Background Radiation Prediction

Determination of appropriate background radiation is important in any measurement application. Environmental radiation monitors and monitors used to assess dose to individuals outside of controlled areas are particularly susceptible to changes in readings due to fluctuations in the environmental conditions. These fluctuations (e.g. radon progeny concentrations) lead to changes in the detector response in the actual radiation environment, and they need to be taken into account when extracting the net operational doses. Work has been ongoing to apply advances in Deep Learning and Artificial Intelligence to account for changes in detector responses based on environmental parameters; in particular, a Long-Short Term Memory (LSTM) Deep Learning architecture has been utilized to incorporate time-series data into a prediction model. In this work, we present the current status of the project to predict radiation measurements based on meteorological conditions and air packet trajectories extracted using the National Oceanic and Atmospheric Administration's (NOAA) Hybrid Single-Particle Lagrangian Integrated Trajectory (HYSPLIT4) model.

Degtiarenko, Pavel↗
DOE OSTI2023

Idaho National Laboratory CY 2022 National Emission Standards for Hazardous Air Pollutants Analysis, Methodology and Results for Radionuclides

This report details calculations of potential dose at public receptor locations surrounding the Idaho National Laboratory (INL) Site boundary, and INL in-town facilities, from radionuclides reported to be in use and potentially emitted from INL facilities during calendar year (CY) 2022. All calculations were performed in accordance with the requirements in Code of Federal Regulations (CFR), Title 40, “Protection of the Environment,” Part 61, “National Emission Standards for Hazardous Air Pollutants (NESHAPs),” Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” (40 CFR 61, Subpart H). Modeling methodology, model input parameters, and contribution to dose by facility, source, and radionuclide at the maximally exposed individual (MEI) location are also discussed. The information in this report supports the “National Emission Standards for Hazardous Air Pollutants – Calendar Year 2022 INL Report for Radionuclides” (DOE-ID 2023). In CY 2022, the estimated annual potential dose at the INL Site MEI location was 1.78E-02 mrem/yr, down from the previous year, and far less than the regulatory standard of 10 mrem/yr (CFR 40 Part 61, Subpart H). Approximately 87% of the total dose to the INL Site MEI originated from Materials and Fuels Complex sources. Emissions from INL in-town facilities resulted in an estimated annual potential dose of 4.03E-03 mrem/yr to the MEI, down 35% from the CY 2021 estimated dose. Year-to-year variations in estimated annual dose can be attributed to adjustments in laboratory operations, changes to facility infrastructure, and variation in meteorological conditions.

11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS↗
DOE OSTI2023

Update of Receptor Locations for INL National Emissions Standard for Hazardous Air Pollutants (NESHAP) Assessments

This report documents the selection of updated public receptor locations for use in conducting regulatory assessments of radioactive air emissions for Idaho National Laboratory (INL) facilities. The basis for this receptor location analysis is found in 40 CFR 61 Subpart H, “National Emissions Standards for Emissions of Radionuclide Other than Radon from Department of Energy Facilities,” where the requirements for identifying National Emission Standards for Hazardous Air Pollutants (NESHAP) receptor locations are outlined. Receptor locations (residences, schools, businesses, or farm operations) were identified using high-resolution satellite imagery. This assessment identified 31 unique receptor locations for all INL Site facilities, and 30 receptor locations for INL in-town facilities that have the potential to emit radioactive materials. Identification of receptors for each in-town facility is new to this report.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗
DOE OSTI2023

2022 LANL Radionuclide Air Emissions Report (Rev. 2)

This report describes the emissions of airborne radionuclides from operations at Los Alamos National Laboratory (LANL) for calendar year 2022 and the resulting off-site dose from these emissions. This document fulfills the requirements established by the National Emissions Standards for Hazardous Air Pollutants in 40 CFR 61, Subpart H – Emissions of Radionuclides other than Radon from Department of Energy Facilities, commonly referred to as the Radionuclide NESHAP or Rad-NESHAP. Compliance with this regulation and preparation of this document is the responsibility of LANL’s Rad NESHAP compliance program, which is part of the Environmental Protection and Compliance (EPC) Division. The information in this report is required under the Clean Air Act and is being submitted to the U.S. Environmental Protection Agency (EPA) Headquarters and EPA Region 6. The highest effective dose equivalent (EDE) to an off-site member of the public was calculated using procedures specified by the EPA and described in this report. LANL’s EDE was 0.45 for 2022. The annual limit is 10 millirem per year, established by the EPA in 40 CFR 61 Subpart H. All measured air emissions are modeled to a single location, known as the Maximally Exposed Individual (MEI). During calendar year 2022, LANL continuously monitored radionuclide emissions at 27 “major” release points, or stacks. The Laboratory estimates emissions from an additional 34 “minor” release points using radionuclide usage source terms in lieu of stack monitoring. Also, LANL uses an EPA approved network of air samplers around the Laboratory perimeter to monitor ambient airborne levels of radionuclides. To provide data for dispersion modeling and dose assessment, LANL maintains and operates several meteorological monitoring towers. From these various systems, a comprehensive evaluation is conducted to calculate the MEI dose for the Laboratory. The MEI can be any member of the public at any off-site location where there is a residence, school, business, or office. In 2022, this MEI location was a business at 95 Entrada Drive, located in the eastern end of Los Alamos town site. The primary contributors to the off-site dose at this location are the ambient air data at that location combined with radioactive gas emissions from the LANSCE facility and the collected potential emissions from unmonitored (minor) sources. Overall, the MEI dose in 2022 is similar to that which has been observed in recent years, and it remains well below the EPA’s 10 millirem per year limit. Doses reported to the EPA for the past 10 years are shown in Table E1.

54 ENVIRONMENTAL SCIENCES↗
DOE OSTI2021

PNNL Sequim Campus Radionuclide Air Emissions Report for Calendar Year 2020

The U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest Site Office has oversight and stewardship duties associated with the Pacific Northwest National Laboratory Sequim Campus. Some research projects have the potential to emit low levels of radioactive materials. This report is prepared to document compliance with the Code of Federal Regulation, Title 40, Protection of the Environment, Part 61, National Emission Standards for Hazardous Air Pollutants, Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” and Washington Administrative Code Chapter 246-247, "Radiation Protection–Air Emissions." Compliance is indicated by comparing the estimated effective dose equivalent (EDE) to the maximally exposed individual (MEI) member of the public with the 10 millirem per year (mrem/yr) U.S. Environmental Protection Agency (EPA) standard. The PNNL Sequim Campus has only fugitive emissions sources. Despite the fact that the regulations are intended for application to point source emissions, fugitive emissions are included with regard to complying with the EPA standard. The EDE to the Campus MEI due to routine operations in 2020 was 3.5E-05 mrem (3.5E-07 mSv). No non-routine emissions occurred in 2020. The Sequim Campus is in compliance with the federal and state 10 mrem/yr standard.

40 CFR 61 Subpart H↗
DOE OSTI2022

PNNL Sequim Campus Radionuclide Air Emissions Report for Calendar Year 2021

The U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest Site Office has oversight and stewardship duties associated with the Pacific Northwest National Laboratory Sequim Campus. Some research projects have the potential to emit low levels of radioactive materials. This report is prepared to document compliance with the Code of Federal Regulation, Title 40, Protection of the Environment, Part 61, National Emission Standards for Hazardous Air Pollutants, Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” and Washington Administrative Code Chapter 246-247, "Radiation Protection–Air Emissions." Compliance is indicated by comparing the estimated effective dose equivalent (EDE) to the maximally exposed individual (MEI) member of the public with the 10 millirem per year (mrem/yr) U.S. Environmental Protection Agency (EPA) standard. The PNNL Sequim Campus has only fugitive emissions sources. Despite the fact that the regulations are intended for application to point source emissions, fugitive emissions are included with regard to complying with the EPA standard. The EDE to the Campus MEI due to routine operations in 2021 was 5.4E-05 mrem (5.4E-07 mSv). No non-routine emissions occurred in 2021. The Sequim Campus is in compliance with the federal and state 10 mrem/yr standard.

40 CFR 61 Subpart H↗
DOE OSTI2023

PNNL-Sequim Campus Radionuclide Air Emissions Report for Calendar Year 2022

The U.S. Department of Energy Office of Science (DOE-SC) Pacific Northwest Site Office has oversight and stewardship duties associated with the Pacific Northwest National Laboratory Sequim Campus. Some research projects have the potential to emit low levels of radioactive materials. This report is prepared to document compliance with the Code of Federal Regulation, Title 40, Protection of the Environment, Part 61, National Emission Standards for Hazardous Air Pollutants, Subpart H, “National Emission Standards for Emissions of Radionuclides Other than Radon from Department of Energy Facilities” and Washington Administrative Code Chapter 246-247, "Radiation Protection–Air Emissions." Compliance is indicated by comparing the estimated effective dose equivalent (EDE) to the maximally exposed individual (MEI) member of the public with the 10 millirem per year (mrem/yr) U.S. Environmental Protection Agency (EPA) standard. The PNNL-Sequim Campus has only fugitive emissions sources. Despite the fact that the regulations are intended for application to point source emissions, fugitive emissions are included with regard to complying with the EPA standard. The EDE to the Campus MEI due to routine operations in 2022 was 7.5E-07 mrem (7.5E-09 mSv). No non-routine emissions occurred in 2022. The PNNL-Sequim Campus is in compliance with the federal and state 10 mrem/yr standard.

40 CFR 61 Subpart H↗
DOE OSTI2023

Quantifying the Impact of Excluding the Submersion Exposure Route for Existing Superfund Radionuclide Screening Level Calculator Soil and Tap Water Models

The U.S. Environmental Protection Agency (EPA) provides initial data screening guidelines for radionuclide-contaminated Superfund sites using preliminary remediation goals (PRGs) and dose compliance concentrations (DCCs). PRGs and DCCs are target concentration values based on acceptable excess lifetime cancer risk and annual dose limits, respectively. They are calculated for various environmental media that may be encountered by residential and worker land uses. PRGs and DCCs typically consist of multiple exposure routes. One of these routes is submersion, which is exposure to a gaseous or particulate radionuclide that is suspended in air. Currently, submersion is only included in air calculations. This study focused on determining whether factoring submersion into total PRG/DCC calculations for soil and tap water created a significant difference in the target concentrations. New equations for individual submersion PRGs/DCCs for each land use of interest for soil and tap water were developed. A wind-driven particulate emission factor and Andelman’s constant were used to model the amount of soil and vapor in the air from soil and household use of tap water, respectively. The submersion PRG/DCC was then included in the total PRG/DCC for each radionuclide, followed by a percent difference comparison of the old and new totals to quantify the impact of the change. For total soil PRGs/DCCs, with and without submersion, the difference was less than 1 percent; however, many of the tap water radionuclides analyzed – including multiple radon and polonium isotopes – showed as high as a 200 percent difference.This technical memorandum (TM) presents recommendations for updates to current EPA guidelines for initial data screens of radionuclide contaminated tap water.

12 MANAGEMENT OF RADIOACTIVE AND NON-RADIOACTIVE W↗