Evaluation of dose attenuation factor of armored car against radiation accidents

Sato, Tatsuhiko   ; Fujii, Katsutoshi ; Murayama, Takashi; Sakamoto, Yukio; Yamaguchi, Yasuhiro; Sato, Yukio*; Soma, Nobuyuki*; Fujisaki, Noboru*; Hara, Satoshi*; Aikawa, Yukio*; Takahashi, Toru*

Tokyo Fire Department developed an armored car against radiation accidents. Dose attenuation factors of the radiation shields had been determined by a simple estimation, and a more precise evaluation was required. By request from Tokyo Fire Department, a precise evaluation of the dose attenuation factor was carried out. The evaluation was done by a Monte Carlo radiation transport simulation code MCNP4B. Benchmark experiments using neutron and gamma ray sources were also performed for ensuring the evaluation method. As a result, it was found out that doses of neutron and gamma ray were attenuated to approximately 10% and 25% by the thickest shield, respectively. These values were close to the ones which had already obtained by the simple estimation.