Source term estimation by reverse analysis

Nagai, Haruyasu

no journal, , 

JAEA has estimated the atmospheric releases of radionuclide during the Fukushima Daiichi Nuclear Power Station (FNPS1) accident by comparing measurements of air concentration of a radionuclide or its dose rate in the environment with the ones calculated by atmospheric transport and deposition model WSPEEDI. The United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) has used our source term for estimating levels of radioactive material in the environment and doses to the public. To improve our source term, we recently made detailed source term estimation by using additional monitoring data near the FNPS1 and WSPEEDI including new deposition scheme. The simulation of modified WSPEEDI and the new source term successfully reproduced the local and regional deposition pattern of I and Cs.