Incorporation of HPAC 5.0 Transport Phenomenology to RASCAL's Radiological Releases

Conference · Tue Jan 01 00:00:00 EST 2008

OSTI ID:936285

Sanders, Robert Lon ^[1]

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1. ORNL

The purpose of this paper is to describe the incorporation of DTRA's HPAC (Hazard Prediction and Assessment Capability) code under the NRC's code RASCAL (Radiological Assessment System for Consequence AnaLysis). The current version of RASCAL (version 3.0.5) evaluates releases from: nuclear power plants, spent fuel storage pools and casks, fuel cycle facilities, and radioactive material handling facilities. It appears to be a single piece of software; however, it is a set of inter-linked modules. These elements include: (1) Source term: this module calculates a time-dependent source term, which for nuclear power plants, is composed of about 50 radionuclides including parents and daughters; (2) Meteorological data processor: this module interrupts weather observations and forecasts along with local topography to generate time-dependent wind fields used in the transport of the plume; (3) Atmospheric transport and diffusion: this module uses the wind fields with a two-dimensional Gaussian puff model to transport the plume downwind and to calculate concentrations of each radionuclide as a function of time and location; (4) Dose calculator: this module calculates various types of doses resulting from airborne releases (TEDE, thyroid, acute, etc.) to individuals at each location from three dose pathways--inhalation, cloudshine, and groundshine. It also calculates the longer-term intermediate phase doses from deposited radionuclides. The calculations are completely consistent with the EPA protective action guide manual and the methods adopted by the Federal Radiological Monitoring and Assessment Center (FRMAC); (5) Display of results: this module allows the user to display a wide variety of calculated results as either a picture of the plume footprint on a map background for each of the result types or as numeric table; and (6) Uranium hexafluoride module: for uranium hexafluoride releases, RASCAL contains a heavy gas model to account for the exothermic reaction with air and gravitational slumping of the plume. In summary, the incorporation of HPAC transport methodology under RASCAL provides for a much more defined prediction of the dispersion of the radiological material as well as the latest dose conversion factors following a postulated accident.

• Research Organization: Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
• Sponsoring Organization: Work for Others (WFO)
• DOE Contract Number: DE-AC05-00OR22725
• OSTI ID: 936285
• Resource Relation: Conference: American Nuclear Society: 2008 Annual Meeting, Anaheim, CA, USA, 20080608, 20080608
• Country of Publication: United States
• Language: English