RESRAD-RDD is used to evaluate human radiation exposures during the early, intermediate, or late phase of response after a radiological dispersal device (RDD) incident.


RESRAD-RDD is a computer code developed to derive operational guidelines for use in emergency planning and response associated with a radiological dispersal device (RDD) 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 the protection action guides (PAGs) in terms of radiation doses established by the U.S. Environmental Protection Agency (EPA 400-R-92-001).

Modeling Approach

The operational guidelines are organized into seven groups that are generally characterized by the phase of response in which they would be implemented or used. Individual groups are further categorized into subgroups, as appropriate. The operational guideline groups considered in RESRAD-RDD 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, and (G) control of food consumption and/or related agricultural activities, in early phase, intermediate, and intermediate-to-late phase of response.

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 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 Group G, which considers radiation exposure from the food ingestion pathway, 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.


A user-friendly interface facilitates data entry, performing calculations, displaying calculation results, and accessing general and context-specific help. 11 radionuclides that are considered to be most likely involved in an RDD incident and their ICRP-30 or ICRP-60 based dose conversion factors are included in the database. 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 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 and Liberty RadEx 2010. 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 at a training workshop at Argonne National Laboratory.