A Numerical simulation of atmospheric dispersion of Kr released from the Rokkasho Reprocessing Plant by an atmospheric dispersion model in SPEEDI-MP

Terada, Hiroaki; Nagai, Haruyasu; Isogai, Keisuke*; Nitta, Wataru*

no journal, , 

We have been verifying and improving SPEEDI-MP which is a comprehensive prediction system of migration of radionuclides in the atmosphere, ocean, and terrestrial region. In this study, we conducted atmospheric dispersion simulations of radioactive noble gas Kr released from the Rokkasho reprocessing plant for the whole Japan area by using an atmospheric model in SPEEDI-MP, and analyzed significant increases of atmospheric Kr concentration above its background level measured by Japan Chemical Analysis Center. Meteorological fields such as wind field and turbulence were predicted by an atmospheric dynamic model MM5, and atmospheric dispersion of Kr was calculated by a Lagrangian particle dispersion model GEARN. The calculation results agreed well with the measurements of atmospheric Kr concentration at Dazaifu in April 2008 and at Sapporo in September 2008 to confirm the high prediction performance of the model.