Atmospheric Dispersion and Deposition of Radionuclides from the Fukushima Daiichi Nuclear Power Plant Accident

On March 11, 2011, an earthquake and tsunami hit the northeast coast of Japan and damaged the Fukushima Daiichi nuclear power plant, leading to the release of radioactive material into the atmosphere. We trace the evolution of radioactivity release to the atmosphere and subsequent dispersion as simulated by models, and we compare these to actual measurements. Four main release periods are highlighted. The first event had limited consequences to the north of the power plant along the coast; the second had no impact on Japanese territory because the plumes travelled toward the Pacific Ocean; the third was responsible for significant and longterm impact, especially northwest of the plant; and the last had consequences of lesser impact on the Tokyo area.