Physicists Model Radioactivity Risk Fukushima Nuclear Site

On March 11, 2011, an earthquake triggered a tsunami that struck Japan’s northeastern coast and flooded the emergency generators in the Fukushima nuclear power plant. The generators had kept the plant’s cooling system operational in the aftermath of the earthquake, but the loss of power ultimately caused a meltdown in three reactors. Tens of thousands of residents were evacuated from the area, and many have been unable to return.

Scientists at Firat University in Turkey have become the first to create spatial analyses of the distribution of hazardous radioactive fallout around the Fukushima site. The team of physicists used Surfer software to model the spatial distribution of deadly iodine-131 radionuclide in two and three dimensions extending up to 60 km from the reactor for a period of 60 days following the disaster.

Led by Prof. Fatih Kulahci of the Firat University Nuclear Physics Division, the team used the Surfer models to generate animated simulations of the iodine-131 spread over distance and time. This first-of-its-kind simulation based on an actual nuclear accident will be critical in predicting the fallout behavior as well as risks over time and distance in future events, explained Dr. Kulahci.

Due to the radioactive nature of the iodine isotope, risk analysis is important in determining the potential for detrimental health impacts on people nearby. For this study, the primary transport mechanism for the isotopes was atmospheric, but dangerous nuclear materials can become contaminants in the soil and move with ground waters. 

The Turkish physicists obtained iodine-131 measurements recorded at 19 stations operated by the Japanese government around the stricken nuclear plant. The team modeled these distributions in 2D and 3D using Surfer visualization software, a package selected for its high resolution and ease of use. The models simulated a prediction of how concentrations of the isotope changed over time in a 60-km radius.

Kulahci’s team generated three types of risk analysis models in Surfer, which were converted into mp4 animations. The first two visualized the probability of occurrence and non-occurrence of airborne iodine-131 over time and distance around the plant. The third model predicted the spread of isotopes by airborne concentrations outward from the nuclear facility, dramatically visualizing the risk of radioactivity exposure in the aftermath of the deadly event.

View the simulations as animations* below.

 Probability of occurrence or risk:

Probability of occurrence or risk animation created with Surfer



Probability of non-occurrence or reliability:

Probability of non-occurrence or reliability animation created with Surfer



Risk Analysis:

Risk Analysis animation created with Surfer


*: Külahcı, F. & Bilici, A. Advances on identification and animated simulations of radioactivity risk levels after Fukushima Nuclear Power Plant accident (with a data bank): A Critical Review J Radioanal Nucl Chem (2019) 321: 1.


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