This paper will describe the support provided by the Department of Energy's National Atmospheric Release Advisory Center (NARAC) during the Fukushima Dai-ichi nuclear power plant crisis. During the Fukushima response, NARAC produced a variety of predictions and analysis products including: • Daily Japan weather forecasts and atmospheric transport predictions to provide situational awareness and inform planning for U.S. measurements surveys and field operations • Estimates of possible dose in Japan using U.S. Nuclear Regulatory Commission (NRC) analyses of atmospheric releases of radioactivity for planning possible protective actions for U.S. citizen • Estimates of possible plume arrival times and dose estimates for U.S. locations • Plume model refinement based on meteorological analysis and available field data NARAC provides detailed assessments of the consequences of atmospheric releases of hazardous materials via a suite of atmospheric dispersion modeling tools that incorporate meteorological, geographic and demographic data, as well as hazardous material information, to predict the transport and potential downwind consequences of biological, chemical, radiological/nuclear, and natural releases. NARAC experts at Lawrence Livermore National Laboratory (LLNL) are available 24/7 to provide quality-assured analyses, utilize observations and field measurement data to refine analyses, and assist decision makers in product interpretation. The center supports real-time emergency response, pre-planning and post-incident assessments, and research.

This work was performed under the auspices of the U.S. Department of Energy by Lawrence Livermore National Laboratory under Contract DE-AC52-07NA27344. LLNL-ABS-492561.