RESRAD-RDD&IND
RESRAD-RDD&IND is used to evaluate human radiation exposures during the early, intermediate, or late phase of response after a radiological dispersal device (RDD) or improvised nuclear device (IND) incident.
Objectives
RESRAD-RDD&IND is a computer code developed to support the implementation of the Department of Homeland Security's (DHS's) protective action guides (PAGs) (73 FR 149) and implementation of the 2017 EPA PAG Manual (EPA 400 R-17-001); and to calculate dose or to derive operational guidelines for use in emergency planning and response associated with a radiological dispersal device (RDD) incident and/or an improvised nuclear device (IND) incident. The operational guidelines are expressed in terms of ground surface radioactivity concentration levels (for comparison with measurement data) or stay times (with known radioactivity concentrations) in the contaminated area and correspond to PAGs in terms of radiation doses.
Modeling Approach
The operational guidelines and dose calculations for an RDD or IND event are organized into eight groups that are generally categorized by the phase of emergency response in which they would be implemented or used for planning purposes. Individual groups are further categorized into subgroups, as appropriate. The operational guideline groups considered in RESRAD-RDD&IND are: (A) access control during emergency response operations, for life- and property-saving measures and emergency worker demarcation, (B) early-phase protective action, concerning evacuation or sheltering of the general public, (C) intermediate-phase protective action, concerning critical infrastructure utilization in relocation areas, (D) temporary access to relocation areas for essential services, concerning worker access to business or public access to residences, (E) access control to transportation routes, including bridges, streets and thorough fares, and sidewalks and walkways, (F) late-phase protective action, concerning release of personal and real properties from radiological controlled areas, (G) control of food consumption and/or related agricultural activities, in early, intermediate, and intermediate-to-late phase of response, and (H) water consumption in early to late phase of response.
For dose calculations, the same methods are used for both RDD and IND incidents for all groups except Group A. For an IND incident in Group A, many short-lived radionuclides are released after a nuclear detonation. A special empirical power function method is used to estimate the external radiation dose as a function of time in the early phase.
To calculate dose or to derive operational guidelines, multiple scenarios representing likely exposure conditions were developed for dose calculation; the one that would result in the highest dose is used for determining the final guideline values. Radionuclides released in an RDD or an IND incident are assumed to deposit on multiple surfaces, including the ground surface, roof top, exterior walls, and interior floor and walls of buildings in the affected areas. Radionuclides are considered to be resuspended into the air and to undergo radiological and weathering decay. Except for Groups G and H, which consider radiation exposure from the food and water ingestion pathways, for other groups, radiation dose is considered to be contributed by the external radiation (direct and air submersion), inhalation of dust particles and radon, and the incidental ingestion of dust particles pathways. A consistent methodology and default parameter values are applied across different groups as appropriate. However, default parameter values can be replaced with measured or more realistic values for obtaining incident-specific operational guidelines.
Features
A user-friendly interface facilitates data entry, performing calculations, displaying calculation results, and accessing general and context-specific help. For RDD, 11 radionuclides, which are considered to be most likely involved in an RDD incident, are included in the RESRAD-RDD&IND code; whereas for IND, more than 90 radionuclides associated with uranium-fueled detonation are included in the RESRAD-RDD&IND code. The dose conversion factors (DCFs) for all radionuclides from three DCF datasets are included in the RESRAD-RDD&IND code. An HTML report containing the calculated guideline results, input parameter values used, as well as scenarios considered and assumptions employed is generated after each calculation.
Use and Applications
The RESRAD-RDD&IND methodology supports the implementation of Department of Homeland Security Planning Guidance in 2008. It was applied to assist decision making during the EMPIRE 09 RDD Exercise, Liberty RadEx 2010, and Cobalt Magnet 25 Exercise. The methodology was also applied in the radiological dose assessment concerning control of agricultural activity and train-riding safety after the Fukushima Daiichi Nuclear Power Plant incident.
Learn more about the use and applications of RESRAD-RDD&IND at a training workshop at Argonne National Laboratory.