Why Fukushima Radiation Spread Far More Widely Than Models Expected

Fallout modeling is complicated. How does one predict where radioisotopes from a nuclear event will travel? One factor used to predict fallout patterns is the weight of the radioisotope. Radioisotopes such as uranium and plutonium are heavy and therefore are likely to fallout closer to the source than the lighter noble gasses. 

Atmospheric air conditions play a role in fallout. The force of the jet stream over Fukushima helped disseminate the hot radioactive particles that were forced upwards. So, fallout models must address local atmospheric conditions to have any predictive validity.

Fallout modeling can incorporate conclusions from past efforts to empirically map fallout, especially from atmospheric tests and the Chernobyl disaster. However, in the case of the Fukushima disaster, fallout projections based on previous dispersion patterns may not apply.

The use of sea water to cool reactors during the early days of the disaster increased the transportability of Fukushima radioisotopes. Research has demonstrated that the presence of alkali metal ions, such as sodium, on uranium can produce spherical uranium peroxide clusters, described as buckyballs, that are highly durable in air and water. The original research article warned that stable nanoscale uranyl peroxide clusters would persist and be transported in water and air.[i]

 Failure to account for this effect might compromise research findings on Fukushima fallout. That is, modeling studies are not likely to be predictive of the extent of fallout dispersion unless they account for the effects of sea water on radioisotopes. 

Just how contaminated is your neighborhood from Fukushima and other nuclear disasters that have occurred around the world regularly since the bombs were dropped in Trinity, Hiroshima and Nagasaki?

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[i]           C. Armstrong, M. Nyman, T. Shvareva,  G. Sigmon, P. Burns, and A. Navrotsky (2012) ‘Uranyl Peroxide Enhanced Nuclear Fuel Corrosion in Seawater’, PNAS, 109.6, 1874-1877.