Enhanced Capabilities of RESRAD-BIOTA: A Computer Program Providing a Graded Approach for Assessing Radiological Impact to Nonhuman Biota
S.L. Domotor1; K.A. Higley2; C. Yu3; D. LePoire3; T. Klett3; and S. Kamboj3 (1US Department of Energy; 2Oregon State University; 3Argonne National Laboratory)
The RESRAD-BIOTA code provides a complete spectrum of capabilities for analyzing nonhuman biota in the environment. They range from simple screening (Level 1) to realistic dose investigation (Level 3) methods. The code was designed to be consistent with and to implement the U.S. Department of Energy (DOE) graded approach for evaluating radiation doses to aquatic and terrestrial biota. A standard assessment starts at Level 1 and proceeds to Level 3 if the initial assumptions prove too conservative or more accurate assessments are desired. Few inputs are required at Level 1, and the output is a comparison to an acceptable environmental concentration (biota concentration guide [BCG]). At Level 3, fewer a priori assumptions are made, but more site- or receptor-specific input data are required, and the output can be provided as a dose rate to specific biota. A new version of the code contains improved features and new capabilities. These include (1) improved graphics and reporting options, (2) BCGs for 14 additional radionuclides, and (3) an advanced food chain model that allows the user to specify multiple food sources. This revised version is part of the ongoing effort by DOE and the Biota Dose Assessment Committee (BDAC) to extend the code's utility to a variety of applications. RESRAD-BIOTA continues to be enhanced, with the planned data library expansion of 14 radionuclides scheduled for late 2005. These nuclides have been selected to encompass potential radiological dispersal device (RDD) sources, sources found in naturally occurring radioactive material, and sources expected to be significant in decommissioning efforts. BDAC participation in international initiatives like the International Atomic Energy Agency's Environmental Modeling for Radiation Safety (EMRAS) Program provides additional opportunities for RESRAD-BIOTA benchmarking, which will foster continuous improvement of the code.