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A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Argonne National Laboratory Office of Science U.S. Department.

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Presentation on theme: "A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Argonne National Laboratory Office of Science U.S. Department."— Presentation transcript:


2 A U.S. Department of Energy Office of Science Laboratory Operated by The University of Chicago Argonne National Laboratory Office of Science U.S. Department of Energy Modeling Radionuclide Transport in the Environment and Assessing Doses to Humans, Flora, and Fauna: The RESRAD Family of Codes Charley Yu, PhD, CHP RESRAD Program Manager Environmental Science Division University of Cincinnati / Ohio State University Joint Nuclear & Radiological Engineering Graduate Seminar Series May 9, 2006

3 Pioneering Science and Technology 2 Presentation Outline ●What is RESRAD ●RESRAD Family of Codes ●Pathway Analysis ●Cleanup Criteria ●Dose Calculation for Human ●Parameter Databases ●Indoor Contamination and Exposure ●Dose Limits for Human and Biota ●Reference Animals and Plants ●Dose Calculation for Biota

4 Pioneering Science and Technology 3 What Is RESRAD? RESRAD is a computer code developed at ANL to calculate: Site specific RESidual RADioactive material guidelines (cleanup criteria or DCGLs), and Radiation dose and excess lifetime cancer risk to an on-site resident (a maximally exposed individual or a member of a critical population group)

5 Pioneering Science and Technology 4 RESRAD Family of Codes

6 Pioneering Science and Technology 5 Major Pathways Considered in RESRAD Radiological Dose/Cancer Risk Calculation: External radiation exposure Internal radiation dose from inhalation (dust and radon) Internal radiation dose from ingestion - drinking water (surface and/or groundwater) - produce, meat and milk - fish - soil

7 Pioneering Science and Technology 6 Scenarios Are Generated by Selecting Various Pathways in RESRAD Dust, Radon Drinking Water Fish Plant Foods Meat Milk Radioactively Contaminated Material in Soil Soil Ingestion Infiltration Leaching External Surface Water Groundwater

8 Pioneering Science and Technology 7 Radiological Release Criteria H E (t) < H EL H E (t) = dose from all pathways (mrem/year) H EL = basic dose limit = 25 mrem/year (NRC) = 0.25 mSv/year

9 Pioneering Science and Technology 8 Single Radionuclide Guideline RESRAD calculates homogeneous soil guidelines (cleanup criteria or DCGLs) for each radionuclide specified by the user for the applicable exposure pathways Guidelines are concentrations of radionuclides in soil for which the basic dose limit will not be exceeded over the selected time horizon (usually 1000 years following remedial action) Use Sum of Fraction rule for multiple radionuclides

10 Pioneering Science and Technology 9 Mass balance is maintained between the contaminated source and each transport pathway RESRAD keeps track of source losses from radioactive decay, leaching, erosion, resuspension and volatilization RESRAD accounts for ingrowth of daughters from initially present parent radionuclides ICRP-38 radionuclide database is recently incorporated (~ 830 nuclides) Source Term and Mass Balance

11 Pioneering Science and Technology 10 Schematic Representation of the Water Pathway Segments

12 Pioneering Science and Technology 11 Water Pathway Models Leaching model: sorption-desorption ion exchange -Input of distribution coefficient (K d ) -Input of groundwater concentration -Input of solubility limit -Input of leach rate -Correlation of K d with soil-plant transfer factors Independent transport of daughter radionuclides Radionuclide transport models: Nondispersive flow, mass balance, and 3-D dispersion

13 Pioneering Science and Technology 12 Residual Radioactive Soil Contamination Air Water Ingestion Dose Plants Meat/Milk Fish Ingestion Pathways

14 Pioneering Science and Technology 13

15 Pioneering Science and Technology 14 Dose Conversion Factors External exposure pathway: -various depths volume factors (mrem/yr per pCi/g) Inhalation pathway: -inhalation factors (mrem/pCi) Ingestion pathways -ingestion factors (mrem/pCi) References:External DCFs -Federal Guidance Report No. 12 (1993) Inhalation/Ingestion DCFs - FGR No. 11 (1988)

16 Pioneering Science and Technology 15 Risk Coefficients or Slope Factors Units of Slope Factors: For external radiation -- risk/yr per pCi/g For inhalation and ingestion pathways-- risk/pCi Source of Slope Factors: EPA publications -- HEAST (2001) Federal Guidance Report No. 13  Morbidity  Mortality

17 Pioneering Science and Technology 16 RESRAD Parameter Databases Decay and ingrowth data (ICRP-38) Dose conversion factors Cancer slope factors (risk coefficients) Food transfer factors (plant/soil, meat/feed, milk/feed, fish/water)

18 Pioneering Science and Technology 17 Site-Specific Input Parameters Physical parameters (size, depth, density, porosity, diffusion coefficient) Hydrological parameters (conductivity, gradient, soil b parameter, water table depth) Geochemical parameters (distribution coefficient, leach rate, solubility) Meteorological parameters (precipitation, evapotranspiration, erosion, runoff, mass loading Usage and consumption parameters (inhalation, irrigation, ingestion, occupancy)

19 Pioneering Science and Technology 18 Selection of Input Parameters For most parameters, RESRAD defaults are representative of national average values or reasonable maximum values Guidance on selecting input values is given in the Data Collection Handbook and the Compilation of Parameter Distributions Sensitivity analysis and probabilistic analysis may be used to focus on parameters for which the use of site-specific data is highly recommended

20 Pioneering Science and Technology 19 PC-based, easy to install, user-friendly code Performs multimedia pathways analysis Simulates multiple exposure scenarios Sensitivity/uncertainty analysis identifies important parameters Many supporting documents to assist users to properly run the model and interpret the results Downloadable free of charge from the RESRAD web site ( Summary of RESRAD Major Features

21 Pioneering Science and Technology 20 Comparison of RESRAD and RESRAD-BUILD RESRAD (soil) and RESRAD-BUILD (building) codes address different contamination sources and uses: RESRAD: Soil contamination which might lead to foodstuffs and water contamination through movement by natural processes RESRAD-BUILD: Building contamination in man-made products and air-flows which might lead to exposure during normal building occupancy or D&D activities in indoor environment

22 Pioneering Science and Technology 21 RESRAD-BUILD Basic Problem x z y

23 Pioneering Science and Technology 22 RESRAD-BUILD Code ●A computer model for analyzing the radiological doses from remediation and occupancy of buildings contaminated with radioactive material ●Includes an air quality model that considers air exchange, deposition and resuspension, and radioactive decay and ingrowth

24 Pioneering Science and Technology 23 Typical Building Geometry

25 Pioneering Science and Technology 24 Pathways, Sources, and Receptors External exposure: direct from source, air submersion, deposited material Inhalation: dust, radon Ingestion: direct from removable material, deposited dust Up to 10 sources: volume, area, line, and point sources Up to 10 receptors in 3 rooms/compartments

26 Pioneering Science and Technology 25 RESRAD-BUILD Pathways Rn Pathway Inhalation External Gamma Ingestion

27 Pioneering Science and Technology 26 Dose (Limits) for Human (mrem or mrem/yr) 5000Worker dose 100Public dose 25NRC cleanup level 10NESHAPS air dose limit 4EPA drinking water limit 300Background radiation 10Chest X-ray 3Air travel for 3000 miles 1IAEA clearance level 1Watch color TV for one year

28 Pioneering Science and Technology 27 ICRP Statements “…if man is adequately protected then other living things are also likely to be sufficiently protected.” (ICRP 1977) “The Commission believes that the standards of environmental control needed to protect man to the degree currently thought desirable will ensure that other species are not put at risk.” (ICRP 1991) “Occasionally, individual members of non-human species might be harmed, but not to the extent of endangering whole species or creating imbalance between species.” (ICRP 1991) “…ICRP therefore needs to revise its current system of protection, and particularly, develop a comprehensive approach to the study of the effects on, and protection of, all living matter with respect to the effects of ionising radiation…” (ICRP 2003)

29 Pioneering Science and Technology 28 Evolution of Dose Limits for Biota Historical setting: –Human limits are dose-based –Protection established by examining all exposure pathways 1990’s DOE considered parallel protection for biota –DOE Standard (DOE Order 5400.5):  1 rad/d (10 mGy/d) for aquatic organisms

30 Pioneering Science and Technology 29 Dose Limits for Biota ●Based on NCRP and IAEA findings ●Other standards proposed ­10 CFR 834, Subpart F:  1 rad/d for aquatic animals  1 rad/d for terrestrial plants  0.1 rad/d for terrestrial animals

31 Pioneering Science and Technology 30 DOE Developed BCGs for Screening BCGs * aquatic riparian terrestrial terrestrial animal animal animal plant * Biota Concentration Guides

32 Pioneering Science and Technology 31 Basic Screening Methodology ●BCG = Dose Limit (rad/yr) Internal + External Dose (rad/yr per pCi/kg) ●Evaluate for unit concentration (e.g., 1 pCi kg -1 ) for single media (e.g., soil) ●Use sum of fractions approach for multiple media (e.g., sediment, water) and radionuclides

33 Pioneering Science and Technology 32 Calculation of Dose to Flora and Fauna ●Calculate tissue concentrations ­Using a simple lumped parameter to relate radionuclide concentration in the media external to the organism to its internal tissues ­Using empirical allometric equations ●Calculate external and internal dose conversion coefficients using the MCNP radiation transport code for various reference animals and plants

34 Pioneering Science and Technology 33 Methodology for Determining DCC Used Monte Carlo transport code MCNP For internal DCC –Organism uniformly contaminated –Calculate energy absorbed in the organism for the electrons and photons emitted from a contaminant (radionuclide) –Assume 100% energy absorbed for alpha emission –Convert energy absorbed to dose For external DCC –Media is uniformly contaminated –Calculate energy absorbed in the organism for the electrons and photons emitted from the contaminated media for each given radionuclide –Assume zero energy absorbed from alpha emission –Convert energy absorbed to dose Internal contamination Soil is contaminated

35 Pioneering Science and Technology 34 Organism Geometries in RESRAD-BIOTA Model Geometry No. Mass Category (Kg) Example Receptors Specific Geometry Dimensions (cm) Specific Mass (Kg) 11E-5Fish egg*, Fish (larvae), Plant root (meristem), Plant seed, Plant shoot (meristem) 0.2 x 0.2 x 0.24.2E-6 21E-3Fish (young-of-year) Molluscs*, Plant seedling, Tadpoles 2.5 x 1.2 x 0.621E-3 31E-2Fathead minnow, Frogs, Hispid cotton rat, Sculpins, Shrews, Voles, White-footed Mouse* 10 x 2 x 22.1E-2 41Black bass, Large fish* Suckers 45 x 8.7 x 4.91 51E1Beaver, Carp, Catfish (Channel and Blue), Coyote, Fox (red or grey), Raccoon*, Striped bass 50 x 26 x 138.8 61E2Mule deer, White-tailed deer*100 x 42 x 3372.6 75E2Elk*270 x 66 x 48447.9 81E3Grizzly bear * 220 x 100 x 1001150

36 Pioneering Science and Technology 35 Dose Coefficients for Duck InternalExternal Radionuclide α DCC (µGy/h per Bq/kg) (γ + β ) DCC (µGy/h per Bq/kg) Soil surface ( µ Gy/h per Bq/kg) Air (µGy/h per Bq/m 3 ) Water surface (µGy/h per Bq/L) H-303.27E-067.2E-141.7E-119.5E-14 C-1402.85E-053.1E-098.5E-091.4E-09 Co-6002.28E-044.0E-043.7E-052.9E-04 Sr-9001.13E-041.8E-073.4E-071.5E-07 Sr-90+D0 6.34E-048.5E-066.4E-067.6E-06 Cs-137+D01.87E-048.4E-059.9E-066.6E-05 U-2382.45E-034.87E-069.6E-095.6E-084.2E-08 Am-2413.21E-032.37E-051.4E-068.8E-073.1E-06 Soil density = 1.6 g/cm 3 ; air density = 0.00129 g/cm 3 ; and water density = 1 g/cm 3

37 Pioneering Science and Technology 36 Features of RESRAD-BIOTA ● Has a user-friendly input interface with Help files ● Users can view dose conversion coefficients (DCCs), dose results, BCG results, etc., and select radiological units ● User can modify lumped parameters (Biv values and Kds), dose limits, area factors, radiation weighting factors, DCFs, and allometric parameters, etc. ● Shows screening results (pass or fail) instantly and have text reports and bar charts.

38 Pioneering Science and Technology 37 RESRAD Family of Codes Downloads by month 425 661 1192 447 479 422 412 385

39 Pioneering Science and Technology 38 RESRAD Downloads by Foreign Countries Foreign Countries (56 Total) ArgentinaCanadaFinlandIsraelMalaysiaPhilippinesSerbiaThailand AustraliaChileFranceItalyMexicoPolandSlovakiaTurkey AustriaChinaGermanyJapanMonacoPortugalSouth AfricaUnited Kingdom BangladeshCroatiaGreeceKazakhstanMontenegroRepublic of MoldovaSpainUkraine BelgiumCzech RepublicHungaryKoreaMoroccoRomaniaSwedenVenezuela BrazilEgyptIndiaLatviaNetherlandsRussiaSwitzerlandYugoslavia BulgariaEstoniaIranMacedoniaPakistanSaudi ArabiaTaiwan

40 Pioneering Science and Technology 39 Thank You! RESRAD Web Site: Email:

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