GENII Version 2GENII Version 2General Purpose EnvironmentalGeneral Purpose Environmental

Radiation SoftwareRadiation Software

GENII Version 2GENII Version 2General Purpose EnvironmentalGeneral Purpose Environmental

Radiation SoftwareRadiation Software

PNNL: Bruce Napier, Dennis Strenge, Van Ramsdell, Christian Fosmire, Mitch Pelton

For EPA Office of Radiation and Indoor Air:

Chris Nelson, Dale Hoffmeyer, Sanjib Chaki, Tony Wolbarst, Kathryn Snead

Support from ORNL: Keith Eckerman

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GENIIGENIIGENIIGENII

A set of computer programs for estimation of radionuclide concentrations in the environment and dose/risk to humans from:Acute or chronic exposures toReleases to surface water or atmosphere,

orInitial contamination conditions

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GENII V.2 in FRAMESGENII V.2 in FRAMESGENII V.2 in FRAMESGENII V.2 in FRAMES

GENII development history

Available Models

Atmospheric transport

Surface water transport

Waste/soil redistribution

Terrestrial uptake

Human Exposure

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GENII V.2 in FRAMES, ContinuedGENII V.2 in FRAMES, ContinuedGENII V.2 in FRAMES, ContinuedGENII V.2 in FRAMES, Continued

Dose/Risk

Uncertainty/Sensitivity

Capabilities and limitations

Walk-through some examples

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GENII DevelopmentGENII DevelopmentGENII DevelopmentGENII Development

1988 - Version 1. Released ICRP-26/30/48 dosimetry

1990 - Version 1.485 stabilized

1992 - GENII-S stochastic version

2004 - GENII Version 2 ICRP-72 age-dependent dosimetryEPA HEAST slope factorsFederal Guidance Report 13 risk factors

2006/7 – V&V

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Exposure ScenariosExposure ScenariosExposure ScenariosExposure Scenarios

“What is the assessment question?”

- F.O. Hoffman

A scenario is a conceptual model that describes patterns of human activity, events, and processes that result in radiation exposure to people.

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Types of ScenariosTypes of ScenariosTypes of ScenariosTypes of Scenarios

Far-Field scenariosAtmospheric transport (Acute or chronic)Surface water transport (Acute or chronic)

Near-Field scenariosSpillsBuried waste(Groundwater use - GW transport modeling is

NOT an explicit part of GENII)

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GENII V.2 Time LineGENII V.2 Time LineGENII V.2 Time LineGENII V.2 Time Line

Dose Period

Release Period Residual Period

Optional inventorydecay/biotic transport

period

Releaseor

disposal

Intake/exposurebegins

Releasestops

Intake/exposureends

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Radionuclides of InterestRadionuclides of InterestRadionuclides of InterestRadionuclides of Interest

All those with half-lives greater than 10 minutes*

All decay progeny of theseSome are included “implicitly”

*(Except radon progeny…)

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Frames sources

Contaminants

Atmospheric transport

Surface water transport

Environmental accumulation

Individual uptake

Dose & risk

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GENII V.2 AtmosphericGENII V.2 AtmosphericTransport OptionsTransport Options

GENII V.2 AtmosphericGENII V.2 AtmosphericTransport OptionsTransport Options

Chronic Gaussian Plume

Chronic Lagrangian Puff

Acute Gaussian Plume

Acute Lagrangian Puff

Input of pre-calculated dispersion parameters (X/Q and D/Q for either acute or chronic, gases and particles)

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GENII V.2 Chronic Plume ModelGENII V.2 Chronic Plume ModelGENII V.2 Chronic Plume ModelGENII V.2 Chronic Plume Model

Straight-line sector-averaged gaussianRuns on hourly observations or joint-frequency dataMultiple independent sources

Ground level or elevated releasesPoint or area sourcesFinite flow correction

Sectors by 16 compass points or 10 degreesRadial output grid

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GENII V.2 Chronic Puff ModelGENII V.2 Chronic Puff ModelGENII V.2 Chronic Puff ModelGENII V.2 Chronic Puff Model

Lagrangian puff releases based on 1 observation pointHourly time step (variable number of puffs/hour)

using hourly observations or quasi-hourly built from joint-frequency data

Square grid

Multiple sourcesPoint or area sourcesGround level or elevated releases

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GENII V.2 Acute Plume ModelGENII V.2 Acute Plume ModelGENII V.2 Acute Plume ModelGENII V.2 Acute Plume Model

Straight-line centerline gaussian for individualsFor short (~2 hour releases)Single sourceGround-level or elevated releases

Radial gridRadial sectors by 16 compass points or 10 degrees

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GENII V.2 Acute Puff ModelGENII V.2 Acute Puff ModelGENII V.2 Acute Puff ModelGENII V.2 Acute Puff Model

Lagrangian puff based on 1 observation pointHourly time step using hourly observations or quasi-hourly

inputs derived from joint-frequency dataSingle sourceSquare gridGround-level or elevated releases

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Parameterizations for Diffusion CoefficientsParameterizations for Diffusion CoefficientsParameterizations for Diffusion CoefficientsParameterizations for Diffusion Coefficients

Briggs open country

Briggs urban conditions

Pasquill-Gifford (ISC-3)

Pasquill-Gifford (NRC: PAVAN, MESORAD, XOQDOQ, etc.)

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Parameterizations AvailableParameterizations Availablein All Air Modelsin All Air Models

Parameterizations AvailableParameterizations Availablein All Air Modelsin All Air Models

Building wake / low-speed meander

Buoyancy-induced diffusion

Plume rise/downwash correctionsMomentumBuoyancy

Diabatic wind profile

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GENII V.2 AtmosphericGENII V.2 AtmosphericDeposition ModelsDeposition Models

GENII V.2 AtmosphericGENII V.2 AtmosphericDeposition ModelsDeposition Models

All models have plume depletion / mass balance

Dry deposition“Resistance model”Includes gravitational settling of larger particles

Wet depositionWashout dependent on precipitation rateRain and snow considered

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GENII V.2 Air Submersion Dose RatesGENII V.2 Air Submersion Dose RatesGENII V.2 Air Submersion Dose RatesGENII V.2 Air Submersion Dose Rates

Infinite plumeBased on Federal Guidance Report 13 models

Finite plumeClose to release - array of line sourcesIntermediate distances - stacked series of infinite planesLong distances - defaults to infinite plume

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Sources of Data for Atmospheric ModelsSources of Data for Atmospheric ModelsSources of Data for Atmospheric ModelsSources of Data for Atmospheric Models

Hourly data CD-144 format (National Climatic Data Center) SAMSON format (NCDC)

1st order stations 1961-1990 on 3 CDs, also a later one

Precipitation in TD-3240 format (NCDC) (For sites in the US, these are now available online from either NCDC

or EPA/CEAM)

Joint frequency data STAR (ISC-3) [provided for many US sites] GENII V.1.485

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GENII V.2 Surface Water Transport ModelsGENII V.2 Surface Water Transport ModelsGENII V.2 Surface Water Transport ModelsGENII V.2 Surface Water Transport Models

Simple models derived from NRC’s LADTAP codeRivers - analog to atmospheric gaussian plume

Constant depth, width, velocityStraight channelContinuous discharge

River - dilution volume (well mixed)Acute river (time integral)Lake

quasi-steady state wind-driven currents

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GENII V.2 Near-Field Soil ModelGENII V.2 Near-Field Soil ModelGENII V.2 Near-Field Soil ModelGENII V.2 Near-Field Soil Model

+--------+ +-¦ Plants ¦ +--------------------------+ ¦ +--------+ ¦ Surface Soil Zone +-¦ +--------+ ¦ (compartment 3) ¦ ¦ ¦ Harvest¦ +--------------------------+ ¦ ¦ Loss ¦ ¦ ¦ ¦ ¦ +--------+ ¦ ¦ ¦ ¦ +--------+ ¦ ¦ +-----¦Leaching¦ ¦ ¦ ¦ +--------+ ¦ ¦ ¦ Biotic Human ¦ Transport Intrusion ¦ ¦ ¦ ¦ +--------------------------+ ¦ ¦ Subsurface Soil Zone +-+ ¦ (compartment 2) ¦ +--------------------------+ ¦ Waste Package Degradation ¦ +--------------------------+ ¦ Buried Waste/Package ¦ ¦ (compartment 1) ¦ +--------------------------+

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GENII V.2 Near-Field Biotic TransportGENII V.2 Near-Field Biotic TransportGENII V.2 Near-Field Biotic TransportGENII V.2 Near-Field Biotic Transport

Plant roots - root fraction applied to CR

Burrowing animals - volume of soil moved versus depth

Applied to arid, humid, or agricultural conditions

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GENII V.2 Near-Field Human IntrusionGENII V.2 Near-Field Human IntrusionGENII V.2 Near-Field Human IntrusionGENII V.2 Near-Field Human Intrusion

Buried waste and/or deep soil may be manually redistributed at the start of exposure to the surface soil.

Process is a step function manual redistribution factor (m3/m2)

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GENII V.2 Exposure PathwaysGENII V.2 Exposure PathwaysGENII V.2 Exposure PathwaysGENII V.2 Exposure PathwaysExternalTransported airSoilSwimmingShoreline

InhalationTransported airResuspended soilVolatilized indoor air pollutants from water

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GENII V.2 Exposure Pathways, ContinuedGENII V.2 Exposure Pathways, ContinuedGENII V.2 Exposure Pathways, ContinuedGENII V.2 Exposure Pathways, Continued

IngestionLeafy vegetables • FishOther vegetables • CrustaceansFruit • MolluscsGrain • Water plantsMeat • Drinking waterMilk • Shower waterPoultry • Swimming waterEggs • Soil

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GENII V.2 Crop ContaminationGENII V.2 Crop ContaminationGENII V.2 Crop ContaminationGENII V.2 Crop Contamination

Plant = Soil * CR + intercepted deposition

Concentration ratios (CR) updated/revisedInterception function of crop biomass

Wet interceptionDry interception

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GENII V.2 Animal Product ContaminationGENII V.2 Animal Product ContaminationGENII V.2 Animal Product ContaminationGENII V.2 Animal Product Contamination

Animal Product = TF (Crop * Ingestion rate)

Transfer factors revised / updated

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GENII V.2 Aquatic Biota ContaminationGENII V.2 Aquatic Biota ContaminationGENII V.2 Aquatic Biota ContaminationGENII V.2 Aquatic Biota Contamination

Fish = Water concentration * BF

Bioaccumulation factors (BF) revised / updated

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GENII V.2 Tritium Specific Activity ModelGENII V.2 Tritium Specific Activity ModelGENII V.2 Tritium Specific Activity ModelGENII V.2 Tritium Specific Activity Model

Environmental media assumed to have same specific activity (Bq/kg water) as contaminating medium (water or air)

Fractional content of both water and non-water portions of the food product is used

In acute cases, rapid equilibration / de-equilibration is assumed (~8 hours)

Based on observations at Chalk River

Includes organically-bound tritium as a “progeny”

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GENII V.2 Carbon-14 Specific Activity ModelGENII V.2 Carbon-14 Specific Activity ModelGENII V.2 Carbon-14 Specific Activity ModelGENII V.2 Carbon-14 Specific Activity Model

For atmospheric sources, model is parallel to that for tritium

For water sources, equilibration is assumed with soil carbon atom ratios

For acute cases, uptake via photosynthesis is slow, long de-equilibration

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GENII V.2 Human ExposureGENII V.2 Human ExposureGENII V.2 Human ExposureGENII V.2 Human Exposure

Up to 6 age groups allowed, following ICRP-56,67,69

3 months 0-1 year1 year 1-2 year5 year 2-7 year

10 year 8-12 year15 year 13-17 year

20 + year 17- 110 year

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GENII V.2 Acute Deposition Food PathwaysGENII V.2 Acute Deposition Food PathwaysGENII V.2 Acute Deposition Food PathwaysGENII V.2 Acute Deposition Food Pathways

GENII V.1.485 presented results for 4 seasons (Winter/spring/summer/autumn)

GENII V.2 now also includes time-dependent model based on the V.1.485 approach – keys off of time of year from meteorological calculationsThis adds more variability to projected answers, and is

more reasonable for retrospective answers

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External Exposure - DosesExternal Exposure - DosesExternal Exposure - DosesExternal Exposure - Doses

Dose rate conversion factors from Federal Guidance Report 12, provided by Keith Eckerman, ORNLAir SubmersionWater ImmersionSoil PlaneSoil Volume

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Internal Exposure - DosesInternal Exposure - DosesInternal Exposure - DosesInternal Exposure - Doses

Effective dose equivalent: ICRP-30Adult only

Effective dose: ICRP-726 age groups24 organs/tissuesInhalation classes F, M, S

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Risk Calculations - Slope FactorsRisk Calculations - Slope FactorsRisk Calculations - Slope FactorsRisk Calculations - Slope Factors

EPA Health Effects Assessment Summary Tables (Currently the same as FGR 13)Ingestion (risk/pCi ingested)Inhalation (risk/pCi inhaled)Ground plane external (risk/year per pCI/g)

For population exposure = adults

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Risk Calculations - Dose-to-Risk Risk Calculations - Dose-to-Risk ConversionsConversions

Risk Calculations - Dose-to-Risk Risk Calculations - Dose-to-Risk ConversionsConversions

ICRP provides estimates of cancer incidence and mortality in relation to effective doseICRP-30 effective doseICRP-72 organ dose

The new US BEIR VII report supports these values with minor revision

Risk = Dose (Sv) * Conversion (risk/Sv)

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Risk Calculations - FGR 13Risk Calculations - FGR 13Risk Calculations - FGR 13Risk Calculations - FGR 13

Federal Guidance Report 13 provides coefficients for 15 cancer sitesInhalation (risk/Bq)

Inhalation classes F, M, S

Ingestion (risk/Bq)Accounts for different consumption patterns with age

- Drinking water- Food crops

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GENII V.2 Uncertainty AnalysisGENII V.2 Uncertainty AnalysisGENII V.2 Uncertainty AnalysisGENII V.2 Uncertainty Analysis

Parameter uncertainty and sensitivity may be addressed using the SUM3 processor in FRAMES.

All non-control parameters are allowed to be varied, using description files to define ‘available’ parameters

Acute atmospheric releases are an important subset. For these, SUM3 is used to vary start times in the plume or puff models, allowing construction of the location or site cumulative dose/risk distribution function.

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Use of SUMUse of SUM33 to get CDF of Dose to get CDF of DoseUse of SUMUse of SUM33 to get CDF of Dose to get CDF of Dose