Development of calculation code for estimating radiation dose for hypothetical accident of nuclear facility considering radioactive decay chain during atmospheric dispersion of released radionuclides

Takeyasu, Masanori ; Nakano, Masanao ; Sumiya, Shuichi ; Nemoto, Hiromi*; Kanno, Mitsuhiro*; Kurosawa, Naohiro*

The dose to the public at hypothetical accident of nuclear facility is estimated on the basis of the method described in the Japanese meteorological guideline. However, the radioactive decay during atmospheric dispersion of released radionuclide is not considered in the calculation formula in the guideline. Therefore, when the radionuclide of the half life such as a few min is released, the dose may be excessively over-estimated. In this study, the calculation code was developed which could consider the radioactive decay of the released radionuclide and the generation of the product. The dose calculated on the basis of the developed code was compared with that on the basis of the guideline.