1982 Volume 31 Issue 5 Pages 235-239
In order to estimate the fallout amounts of transuranium elements, monthly deposits have been collected at Tokai, Ibaraki Prefecture, during the period from October 1978 to March 1980, and were analyzed both on 241Am and 239+240Pu also on major surface soil components, SiO2 and Al2O3. Major soil matrices contents in the deposits suggested that 5.1 % of the observed 239+240Pu deposition was contributed by resuspension from ground deposit with wind-blow, on the other hand, much greater contribution of 10.3 % of 241Am was by the resuspension.
Fallout amounts exclude resuspension of 241Am and 239+240Pu throughout the period were estimated to be 11.0 and 212 mBq/m2 (0.30 and 5.73 pCi/m2) respectively and annual values were 10.0 and 166 mBq/m2·y (0.27 and 4.49 pCi/m2·y), respectively in 1979. Activity ratios of 241Am/239+240Pu changed widely. The average value of 0.066 was calculated from total amounts of each nuclides.
