Workshop U.S. Nuclear Regulatory Commission Rockville, Maryland Pacific Northwest National Laboratory November 15-17, 2005 GENII Version 2.0 Overview and Examples

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

Types of Scenarios A scenario is a conceptual model that describes patterns of human activity, events, and processes that result in radiation exposure to people. Far-Field scenarios Atmospheric transport (Acute or chronic) Surface water transport (Acute or chronic) Near-Field scenarios Spills Buried waste (Groundwater use - GW transport modeling is NOT an explicit part of GENII)

GENII Timeline Dose Period Release PeriodResidual Period Optional inventory decay/biotic transport period Release or disposal Intake/exposure begins Release stops Intake/exposure ends

Uncertainty Analysis Parameter uncertainty and sensitivity may be addressed using the SUM 3 processor in FRAMES. All non-control parameters are allowed to be varied, using description files to define ‘available’ parameters

Dose Calculations External dose rate conversion factors from Federal Guidance Report 12, provided by Keith Eckerman, ORNL Air Submersion Water Immersion Soil Plane Soil Volume Internal Effective dose equivalent: ICRP-30 Adult only Internal Effective dose: ICRP-72 6 age groups 24 organs/tissues Inhalation classes F, M, S

Risk Calculations EPA Health Effects Assessment Summary Tables (Currently the same as FGR 13; for population exposure = adults) Ingestion (risk/pCi ingested) Inhalation (risk/pCi inhaled) Ground plane external (risk/year per pCi/g) Dose-to-Risk Conversions; estimates of cancer incidence and mortality in relation to effective dose Risk = Dose (Sv) * Conversion (risk/Sv) Federal Guidance Report 13 coefficients for 15 cancer sites Inhalation (risk/Bq) Inhalation classes F, M, S Ingestion (risk/Bq) Accounts for different consumption patterns with age Drinking water Food crops

GENII Limitations Up to 100 radionuclides may be considered in one case Decay chains are limited to 9 members (be careful not to use the MEPAS RMDLIB.DAT file) Radon diffusion model not yet implemented in Near Field model GENII V.2 is still in testing – report problems!

GENII Demonstration Replication of the CAP-88 PC Sample Problem as Described in the GENII v2 User’s Guide 6 co-located emission points in CAP-88 example and GENII only allows 5 locations. Source 1Source 2Source 3Source 4Source 5 Area (m 2 ) Height (m) Exit velocity (m/s) Release (Ci/yr) U E-43.2E-43.2E-99.6E-132.7E-8 U E-62.3E-68.0E-75.5E-63.4E-5 U E-6 U E-43.2E-44.0E-47.6E-43.6E-3

Conceptual Model

Entry of the source term data for Source 1.

Define the radial atmospheric transport grid. There are 12 distances used in CAP-88 example and only 10 distances available in GENII.

Joint Frequency Distribution is available for Erie, PA and Precipitation is available for Buffalo, NY.

For this example, the exposure occurs from years 99 to 100.

For this example, most of the GENII default intake values are suitable.

GENII Walk-Through Example demonstrating key user interfaces Radiation dose to adult individual from chronic release to surface water and aquifer

Example Description 15-year known (i.e., user defined) chronic release to surface water 0.25 pCi/ml Am-241 & 2.5 pCi/ml Pu year known (i.e., user defined) chronic release to aquifer 0.1 to 0 pCi/ml Am-241 & 1 to 0 pCi/ml Pu-239 Local agriculture includes: beef, milk, leafy and root vegetables, fish Other pathways include drinking water, inhalation of indoor air, resuspended soil, external exposure to soil Remaining parameter values are selected by the analyst to meet needs of site-specific analysis.

Select the GENII Radionuclide Database Selection

Select the user defined WCF Surface Water Module because the surface water concentrations are known

Select the user defined WCF Aquifer Module because the aquifer water concentrations are known

Because this was a chronic release, select the GENII V.2 Chronic Exposure Module for environmental accumulation

Select the MEPAS 5.0 Receptor Intakes Module. At this time, the GENII V.2 Receptor Intake Module is not compatible with FRAMES 2.

For comparison exercise, select both the GENII V.2 Health Impacts Module and the MEPAS 5.0 Health Impacts Module.

Enter constant surface water concentrations (i.e., 0.25 pCi/ml Am-241 & 2.5 pCi/ml Pu-239) over 15-year period. Select these arrow buttons to view and enter information for remaining constituents

Enter time-varying aquifer concentrations (i.e., 0.1 to 0 pCi/ml Am-241 & 1 to 0 pCi/ml Pu-239) over 100-year period. Select these arrow buttons to view and enter information for remaining constituents

This is one of the more data-intensive models – these tabs each have multiple pages of entries.

It pays to start with the Pathways tab first. Turn on the pathways that are of interest.

…for example, selecting the Agricultural tab reveals two additional layers of parameter input interfaces. Accept or change values as appropriate.

Accept or change values as appropriate.

The GENII Intake Module (not yet compatible with FRAMES 2) offers choice of age groups and many inputs. Most intakes are defined with a daily intake and the associated number of days/year.

Make selections for GENII Health Impacts using ICRP 30/48. Notice that each of the dose/risk options has additional associated method parameters to select.

Make selections for MEPAS Health Impacts using ICRP dose and risk factors under the Radionuclide tab.

When all lights in the local space are yellow, run each module in sequence. When all lights are green, intermediate and final results can be viewed by right clicking on any module icon and selecting View/Print Module Output.

Questions?Questions?