Source term estimation for the Fukushima Daiichi Nuclear Power Station accident by comparing environmental monitoring and atmospheric dispersion simulation

Nagai, Haruyasu  ; Terada, Hiroaki   ; Chino, Masamichi*

Temporal variations in the amount of radionuclides released into the atmosphere during the Fukushima Daiichi Nuclear Power Station accident and their atmospheric dispersion are essential to evaluate the environmental impacts and resultant radiological doses to the public. We have estimated the atmospheric releases during the accident by comparing measurements with calculations by atmospheric deposition model. UNSCEAR used our source term for estimating levels of radioactive material in the terrestrial environment and doses to the public. To improve our source term, we recently made detailed source term estimation by using additional monitoring data and WSPEEDI including new deposition scheme. We will discuss the effectiveness of a variety of monitoring data for the source term estimation by reviewing our source term estimation results.