A Study on dose control for JCO criticality accident termination

Kanamori, Masashi; Tanaka, Kenichi*; Takada, Jun*

At the time of the JCO criticality accident termination, dose estimation from the preliminary neutron and measurement, it was about around 50 times lower. The estimation might effect from the surrounding buildings. In this report, re-estimation based on the measurements at short distances from the criticality, around 40 m to 100 m, which are 20 mSv/h to 3 mSv/h was done. The re-estimated doses are correspond with the measured doses within 60-80% error. Dose estimation under the high radiation field, around 100 mSv, in order to decide the dose limit for the preliminary measurement, annual dose limit, other exposure possibility and measurement error have to be considered. From this point of view, the dose limit for the preliminary measurement itself considered to be 10 mSv, which is half of annual 20 mSv limit.