Quicker calculation of atmospheric dispersion of radioactive materials under various conditions
—Calculation time reduced to 1/100 using newly-developed "WSPEEDI-DB"—

The previous atmospheric dispersion prediction system, WSPEEDI, was improved in response to the Fukushima Daiichi nuclear power station accident and used to carry out detailed analysis. It has also been used to predict dispersion during nuclear testing by North Korea. However, calculation using a sophisticated prediction model takes time, and thus it was difficult to compare prediction results under various conditions.

Therefore, a new calculation system "WSPEEDI-DB" has been developed. This system drastically improves efficiency in comparing and investigating calculation results on atmospheric dispersion for various weather conditions and arbitrary source term (released radionuclides, release rate, and release period ) by constructing a database of dispersion-calculation results continuously and regularly. Time required is reduced to about 1/100 of the previous time. The calculation code package for this system has been released to the public for use free of charge.

The package is expected to see use in various studies by local governments employing atmospheric dispersion calculation.