Book Description

The GENII Version 2 computer code was developed for the Environmental Protection Agency (EPA) at Pacific Northwest National Laboratory (PNNL) to incorporate the internal dosimetry models recommended by the International Commission on Radiological Protection (ICRP) and the radiological risk estimating procedures of Federal Guidance Report 13 into updated versions of existing environmental pathway analysis models. The resulting environmental dosimetry computer codes are compiled in the GENII Environmental Dosimetry System. The GENII system was developed to provide a state-of-the-art, technically peer-reviewed, documented set of programs for calculating radiation dose and risk from radionuclides released to the environment. The codes were designed with the flexibility to accommodate input parameters for a wide variety of generic sites. Operation of a new version of the codes, GENII Version 2, is described in this report. Two versions of the GENII Version 2 code system are available, a full-featured version and a version specifically designed for demonstrating compliance with the dose limits specified in 40 CFR 61.93(a), the National Emission Standards for Hazardous Air Pollutants (NESHAPS) for radionuclides. The only differences lie in the limitation of the capabilities of the user to change specific parameters in the NESHAPS version. This report describes the data entry, accomplished via interactive, menu-driven user interfaces. Default exposure and consumption parameters are provided for both the average (population) and maximum individual; however, these may be modified by the user. Source term information may be entered as radionuclide release quantities for transport scenarios, or as basic radionuclide concentrations in environmental media (air, water, soil). For input of basic or derived concentrations, decay of parent radionuclides and ingrowth of radioactive decay products prior to the start of the exposure scenario may be considered. A single code run can accommodate unlimited numbers of radionuclides including the source term and any radionuclides that accumulate from decay of the parent, because the system works sequentially on individual decay chains. The code package also provides interfaces, through the Framework for Risk Analysis in Multimedia Environmental Systems (FRAMES), for external calculations of atmospheric dispersion, geohydrology, biotic transport, and surface water transport.