Preparing the MACCS Code for Advanced Reactor Applications

Abstract

The MACCS code was created by Sandia National Laboratories for the U.S. Nuclear Regulatory Commission and has been used for emergency planning, level 3 probabilistic risk assessments, consequence analyses and other scientific and regulatory research for over half a century. Specializing in modeling the transport of nuclear material into the environment, MACCS accounts for atmospheric transport and dispersion, wet and dry deposition, probabilistic treatment of meteorology, exposure pathways, varying protective actions for the emergency, intermediate and long-term phases, dosimetry, health effects (including but not limited to population dose, acute radiation injury and increased cancer risk), and economic impacts. Routine updates and recent enhancements to the MACCS code, such as the inclusion of a higher fidelity atmospheric transport and dispersion model, the addition of a new economic impact model, and the application of nearfield modeling, have continuously increased the codes capabilities in consequence analysis. Additionally, investigations of MACCS capabilities for advanced reactor applications have shown that MACCS can provide realistic and informative risk assessments for the new generation of reactor designs. Even so, areas of improvement as well as gaps have been identified that if resolved can increase the usefulness of MACCS in any application regarding a release of nuclear material into the environment.