Abstract
Official reports on the consequences of the Chernobyl accident consistently denied acute radiation syndrome among inhabitants living around the Chernobyl NPP. On the other side, in the secret protocol of the Soviet Communist Party that was made in April-May 1986 a lot of descriptions were contained about radiation syndrome: more than 10,000 people were hospitalized including children with diagnosis of radiation syndrome. The level of radiation dose can be a reasonable measure to consider whether or not radiation syndrome happened. The average effective dose of 20-30 mSv and the maximum of 400 mSv were estimated for the evacuees by UNSCEAR 2000 report and the Chernobyl Forum 2005 report, based on which radiation syndrome is difficult to be supposed. Meanwhile, biological dosimetry data using dicentric chromosome frequency in lymphocytes indicated the average dose of 400 mSv for 60 evacuees in Belarus (Mikhalevich 2000) and 490 mSv for 27 evacuees in Ukraine (Maznik 1997). We have previously estimated external radiation dose for several settlements up to the evacuation based on radiation monitoring data on May 1, 1986 (6th day of the accident). The average external dose of 320 mSv was obtained for Usov village located about 10 km N from the Chernobyl NPP (Imanaka 2000). Recently new information became available on the direction of radioactive plume movement and radionuclide composition on the ground. Based on these data our efforts are underway to revise dose estimates as well as to find the reason for the difference between our estimates and the official values.
