Atmospheric behavior, deposition, and budget of radioactive materials from the Fukushima Daiichi nuclear power plant in March 2011

Abstract

[1] To understand the atmospheric behavior of radioactive materials emitted from the Fukushima Daiichi nuclear power plant after the nuclear accident that accompanied the great Tohoku earthquake and tsunami on 11 March 2011, we simulated the transport and deposition of iodine-131 and cesium-137 using a chemical transport model. The model roughly reproduced the observed temporal and spatial variations of deposition rates over 15 Japanese prefectures (60−400 km from the plant), including Tokyo, although there were some discrepancies between the simulated and observed rates. These discrepancies were likely due to uncertainties in the simulation of emission, transport, and deposition processes in the model. A budget analysis indicated that approximately 13% of iodine-131 and 22% of cesium-137 were deposited over land in Japan, and the rest was deposited over the ocean or transported out of the model domain (700 × 700 km 2 ). Radioactivity budgets are sensitive to temporal emission patterns. Accurate estimation of emissions to the air is important for estimation of the atmospheric behavior of radionuclides and their subsequent behavior in land water, soil, vegetation, and the ocean. Citation: Morino, Y., T. Ohara, and M. Nishizawa (2011), Atmospheric behavior, deposition, and budget of radioactive materials from the Fukushima Daiichi nuclear

Unexpected source of Fukushima-derived radiocesium to the coastal ocean of Japan

“…Fukushima Dai-ichi Nuclear Power Plant accident | cesium | submarine groundwater discharge | radioactivity | radium O n March 11, 2011, a 9.0-magnitude earthquake triggered a 15-m tsunami that inundated the Fukushima Dai-ichi Nuclear Power Plant (FDNPP), causing power loss, explosions, and reactor meltdowns, releasing a significant quantity of radionuclides into the atmosphere (1)(2)(3). More than 80% of the atmospheric fallout occurred over the ocean, with the highest deposition in the nearshore marine environment (4).…”

Reply to Strub et al.: Chlorine activation by neutrons as an obvious source of 35 S at Fukushima

“…The comments are mostly irrelevant, and we quantitatively address them. The observation of the 35 SO 4 2− peak at La Jolla derived from intense meteorological conditions at Fukushima producing long-range transport of the radiation plume to California (3), and the air mass back trajectories confirm that 35 (3). In addition, the northeasterly winds associated with a transient cyclone increased the sulfate deposition rate over the areas around Fukushima (3).…”

Migration Behavior of Particulate 129I in the Niida River System

“…The total amount of radionuclides discharged into the atmosphere was estimated to be 8.1 GBq for 129 I [1] and 120-150 PBq for 131 I [2,3]. Approximately 13 % of the total amount of released 131 I was deposited over Japan via radioactive plumes [4]. Any short-lived 131 I deposited in the soil decays after a few months, however, long-lived 129 I derived from the FDNPP accident must be traced from land to the marine environment via river systems owing to its relatively high fission yield, high chemical reactivity, biological concentration in the marine ecosystem, and affinity for the thyroid gland although it is less radiologically harmful than 131 I.…”