Analysis of dose distribution for heavily exposed workers in the first criticality accident of Japan

Endo, Akira   ; Yamaguchi, Yasuhiro

The first criticality accident in Japan occurred in a uranium processing plant in Tokai-mura in September, 1999. In this accident, two workers on the site were heterogeneously exposed to neutrons and rays produced by the nuclear fission. Heterogeneous exposure influenced the clinical course observed in the skin and organs of these workers. By request from medical groups, we attempted to clarify the dose distribution of the two heavily exposed workers with the aid of computer simulation, which is currently the only means by which to address this complicated problem. This paper presents elucidated skin dose distributions, depth dose distributions inside the trunk, and neutron-to- dose ratios.