Deposition of radionuclides and stable elements in Tokai-mura

Ueno, Takashi ; Amano, Hikaru

This report presents the data of deposition of radionuclides (Sep. 1993-March 2001) and stable elements (Sep.1993-Oct.1995) in Tokai-mura. To evaluate the migration of radionuclides and stable elements migration from the atmosphere to the ground surface, atmospheric deposition samples were collected from 1993 to 2001 with three basins (distance to grand surface were 1.5m, 4m, 10m) set up in the enclosure of JAERI in Tokai-mura, Ibaraki-ken, Japan. Monthly samples were evaporated to dryness to obtain residual samples and measured with a well type Ge detector for 7Be, 40K, 137Cs and 210Pb. According to the analysis of radioactivity, clear seasonal variations with spring peaks of deposition weight (dry) and deposition amounts of all objective radionuclides were found. Correlation analysis of deposition data also showed that these radionuclides can be divided into two groups. A part of dried sample was irradiated to reactor neutrons at JRR-4 for determination of stable element's deposition.