Overview for Radiological Risk and Dose Assessment Models of

International and National Agencies

Nasser ShubayrResearch Fellow at U.S. Environmental Protection Agency (EPA),

Washington D.C, through ORISE (US DOE)Shubayr.Nasser@epa.gov

Wednesday, April 19, 2017 Performance & Risk Assessment Community of Practice(P&RA CoP)

Outline

General Modeling Approach

Model Overview

General Modeling Approach

• Models are usually used to analyze the exposure sources and scenarios in order to produce guidelines.

• They use a set of calculations, where the input is the parameters for relevant exposure scenario described by mathematical equations and the outputs are soil screening level, risk and dose.

General Modeling Approach, (Cont.)

• The general components of the models are similar in term of: – Selecting radionuclides, – Media & scenario of exposure,– receptor and – output risk/dose.

• The models can deal with generic or site-specific assessments.

General Modeling Approach, (Cont.)

• The models are simplified by technical and scientific assumptions to represent a real-world environmental problem.

• They also are associated with uncertainties of scenarios and parameters.

• Some models have been developed as software and others as an excel spreadsheet.

Models Overview

National

(PRG)

Preliminary

Remediation

Goals

(DCC)

Dose

Compliance

Concentrations

(RESRAD) On-site

RESidual

RADioactive

material

guidelines

(RaSoRS)

Radioactive Soil

Remediation Standards

NCRP Report No. 129

Recommended Screening Limits

for Contaminated

Surface Soil and Review of

Factors Relevant to Site Specific

Studies”:

NRC Report:

Consolidated Decommissioning

GuidanceVolume 1.

International

CROM

Screening

Model for

Environmental

Assessment

SYMBIOSE

Simulation

Platform For

Performing

Radiological

Risk

Assessments

WISMUT

“Wismut” is

referred to the

areas in

Saxony and

Thuringia in

Germany

RCLEA

The

Radioactively

Contaminated

Land Exposure

Assessment

Methodology

NORMALYSA

NORM And

LegacY Site

Assessment

Model

Internet based calculators

PRG

DCC

Software based models

RESRAD

NORMALYSA

SYMBIOSE

CROM

Excel based models

UK RCLEA

NJ RaSoRs

Tables in Reports

NCRP Report No. 129

(NRC), “Consolidated Decommissioning

Guidance

Models

PRG Calculator

• PRG was developed by the U.S. Environmental Protection Agency(EPA) in 2002 and last updated in 2016.

• Internet based calculators, found at the EPA website.

• The PRG calculator is also consistent with EPA’s recommended model for risk assessment for chemicals in soil, water, and air, the Regional Screening Level (RSL) calculator.

PRG Calculator(cont.)

• PRGs can be calculated for 1255 radionuclides.

• They are used for site "screening" and as initial cleanup goals.

PRG Calculator(cont.)

• Calculates radionuclide PRGs for:1. Resident,2. Composite Worker,3. Outdoor Worker,4. Indoor Worker,5. Construction Worker,6. Recreator,7. Consumption of Fish,8. Farmer,9. Soil to Groundwater ,

PRG Calculator(cont.)

• Using the PRG calculator:

PRG Calculator(cont.)

• Parameters for site-specific assessment.

PRG Calculator(cont.)

Output:

DCC Calculator

• The Dose Compliance Concentrations (DCC) calculator was first issued in 2004 and last updated in 2015.

• The DCC calculator is similar to the PRG calculator for demonstrating compliance with dose based regulations.

RESRAD (onsite)

• RESidual RADioactive material guidelines, RESRAD was developed by Argonne National Laboratory for the U.S. Department of Energy in 1989 and updated last in 2016.

• To calculate:1. Site-specific guidelines, 2. radiation doses and 3. excess lifetime cancer risk.

RESRAD (onsite)(cont.)

• A total of nine major exposure pathways are considered in the RESRAD (onsite).• Direct exposure to external radiation,• Internal exposure from inhalation of:1. Airborne radionuclides and 2. Radon progeny;• Internal exposure from ingestion of contaminated :1. Plant foods,2. water,3. Meat, 4. Milk, 5. Fish, 6. Soil.

RESRAD (onsite),(cont.)

RESRAD (onsite),(cont.)

Set Pathways: Select or block exposure pathways.

RESRAD (onsite),(cont.)

Modify Data: change the default parameters to site-specific parameters

RESRAD (cont.)

Soil Contamination:

RESRAD (cont.)

View Output:Summary Report

RESRAD (cont.)

View Output:Other options to view the output.

NORMALYSA

• NORM And LegacY Site Assessment (NORMALYSA) was developed by the International Atomic Energy Agency (IAEA) & adopted by Sweden.

• Library of models organized in four different modules: – Source – Transport – Receptor – Dose

NORMALYSA(cont.)

Context:• New• Open

• Select Radionuclides

• Exposed Group• Other options

NORMALYSA(cont.)

Model: All possible options• Dose• Receptor • Cover• Source• Transport

NORMALYSA(cont.)

After making your scenario, you should connect modules in order to run the simulation

NORMALYSA(cont.)

Input Parameters:

NORMALYSA(cont.)

Simulation: Run•You can’t run the simulation when there are missing values

NORMALYSA(cont.)

Results: Tables and Charts

NORMALYSAReferences (cont.)

• Mostly Swedish Publications• The publications of the Department of Radiation

Protection and Environment in Germany, (Wismut user’s manual).

• IAEA ,2001, 2010• ICRP 71

SYMBIOSE

• Developed by the French Institute for Radiological Protection and Nuclear Safety (IRSN) and Electricity of France (EDF) in 2002.

• The SYMBIOSE platform runs in French/English on Windows, Linux or OS, and

• consists of four major components:– a library of modules, – a library of simulators,– a library of case studies and– the application that manages modules and simulators.

• SYMBIOSE is not available for public, but researchers may acquire a license for research purposes

CROM

• CROM was develop by the University of Madrid and the Environmental Impact of the Energy Department (CIEMAT) in Spain.

• CROM was first issued in 2011 and updated last in 2016.

• CROM contains a default database with about 150 Radionuclides.

CROM(cont.)

• CROM can be used to assess the impact of discharges of radionuclides to the environment. It can be used for continuous and prolonged release.

CROM(cont.)

8 Cases / Scenarios:• Atmospheric dispersion• Dispersion in small lakes and ponds• Dispersion in rivers• Dispersion in estuaries • Dispersion in coastal waters• Hypothetical critical groups and

food concentrations • Human doses• Biota assessment

CROM(cont.)

• Output:• 1. Concentrations in different media and in

food for each of the selected source term radionuclide.

• 2. Doses and routes are shown by radionuclide.

CROM(cont.)

Main references: – IAEA "Generic Models for Use in

Assessing the Impact of Discharges of Radioactive Substances to the Environment". Safety Report Series No 19

– Radiation Protection 72 –Methodology for assessing the radiological consequences of routine releases of radionuclides to the environment.

RCLEA

• RCLEA was developed by DEFRA’s (U.K. Government Department for Environment, Food and Rural Affairs) RCLEA was issued in 2003.

• RCLEA consists of a collection of worksheets that contain all input data and results. – All library values are protected

against change. – The underlying calculations are

also hidden and protected.

RCLEA(cont.)

• Land Use:1. Residential with Home-Grown Produce,2. Residential without Home-Grown Produce,3. Allotments,4. Commercial/Industrial.• Building types:1. Timber,2. Concrete Brick,• Receptor: Infant, Child, Adult,• Receptor Sex: Male, Female.

RCLEA(cont.)

• Select Radionuclides and concentration in (Bq/kg).

RCLEA(cont.)

• Results:1. Dose,2. Guideline value for radionuclide

NJ RaSoRs

• Radioactive Soil Remediation Standards (RaSoRS).• RaSoRS is an Excel based model developed by the

Bureau of Environmental Radiation of the State of New Jersey in 2003.

NJ RaSoRs(cont.)

• NJ RaSoRs contains:– Only 7 radionuclides and their progenies, (U-238,

U-234, Th-230, Ra-226, U-235, Ac-227 and Th-232).

– and assumes two construction scenarios (Basement and Slap-on-Grade)

– For two site use scenarios (Residential and Commercial).

NJ RaSoRs(cont.)

• Simple and limited.

WISMUT

• WISMUT was developed by the Germany Federal Laender and the Wismut GmbH company.

• The name “Wismut” is referred to the areas in Saxony and Thuringia in Germany that were adversely affected by 40 years of unrestrained mining and processing of uranium ores.

• WISMUT model was developed with special considerations for the WISMUT region such levels of natural background for all relevant environmental media in the area.

WISMUT(cont.)

• To assess radiation exposure of members of the public and workers due to environmental radioactivity resulting from mining.

• It is applicable for remediation, decommissioning, reuse of mining plants.

• WISMUT model is not available in English and not accessible due to copyright agreement.

NCRP Report No. 129

National Council on Radiation Protection and Measurements (NCRP) published a report entitled, “Recommended Screening Limits for Contaminated Surface Soil and Review of Factors Relevant to Site Specific Studies” (NCRP Report No. 129) It lists screening guidance for over 200 radionuclides with half-lives greater than 30 days.

NCRP Report No. 129(cont.)

Contains soil guidelines for several Land-Use Scenarios: 1. Agricultural (AG), 2. Heavily Vegetated Pasture (PV),3. Sparsely Vegetated Pasture (PS),4. Heavily Vegetated Rural (RV),5. Sparsely Vegetated Rural (RS),6. Suburban (SU), 7. No Food Suburban (SN), 8. Construction, 9. Commercial, 10.Industrial (CC).

NRC Report

• The US Nuclear Regulatory Commission (NRC) published reports entitled Consolidated Decommissioning Guidance in three volumes:

• 1) Decommissioning Process for Materials Licensees,

• 2) Characterization, Survey, and Determination of Radiological Criteria;

• 3) Financial Assurance, Recordkeeping, and Timeliness.

NRC Report(cont.)

• Volume (1), Decommissioning Process for Materials Licensees, was published in 2006.

• Appendix B (Page B-2 to B-3), contains about 46 Screening Values of Common Radionuclides for Soil Surface Contamination in units of (pCi/g) equivalent to 25 mrem/y.

My research withUS EPA

Studying all Radiation Assessment models

Key Objectives & Benefits of this Project

• Make recommendations on technical and practical issues to the Office of Superfund, EPA.

• Facilitate better understanding of each agency’s approach to tackling problems of land contamination due to radionuclides.

• Identify thematic areas for cooperation..• Enhance the dialogue between various international

and domestic initiatives concerned with land contamination and remediation.

References1. US EPA. (2002 (last updated in 2016)). Preliminary Remediation Goal (PRG). Retrieved from http://epa-prgs.ornl.gov/cgi-

bin/radionuclides/rprg_search .2. US EPA. (2004 (last updated in 2015)). Dose Compliance Concentration (DCC). Retrieved from http://epa-dccs.ornl.gov/cgi-

bin/dose_search .3. ANL. (2001). User’s manual for RESRAD version 6. Environmental Assessment Division, Argonne National Laboratory,

Argonne. Retrieved from https://web.evs.anl.gov/resrad/RESRAD_Family/4. Bureau of Environmental Radiation, NJ. (2003). Radioactive Soil Remediation Standards (RaSoRS). Retrieved from

http://www.nj.gov/dep/rpp/rms/rad_cleanups.htm .5. NCRP. (1999). Recommended Screening Limits For Contaminated Surface Soil and Review of Factors Relevant To Site-

Specific Studies, NCRP Report No. 129.6. Banovac, K. L. (2006). Consolidated Decommissioning Guidance: Decommissioning Process for Materials Licensees: Final

Report. Division of Waste Management and Environmental Protection, Office of Nuclear Material Safety and Safeguards, . US Nuclear Regulatory Commission.

7. U.K. DEFRA . (2003). The Radioactively Contaminated Land Exposure Assessment Methodology (RCLEA):.https://www.gov.uk/government/publications/rclea-software-application.

8. IRSN. (n.d.). SYMBIOSE. Retrieved from https://gforge.irsn.fr/gf/project/symbiose/9. CIEMAT. (2011 ( last updated in 2016)). Screening Model for Environmental Assessment (CROM). Retrieved from

ftp://ftp.ciemat.es/pub/CROM/CROM_8/10. (IAEA). (2015). NORM And LegacY Site Assessment (NORMALYSA). Retrieved from

http://project.facilia.se/normalysa/software.html .11. . Department Radiation Protection and Environment. (2011). Calculation Guide for the Determination of Radiation Exposure due

to Environmental Radioactivity Resulting from Mining. GERMANY.

Questions?

Thank you!