Deposition of 241 Am and 233 + 240 Pu at Tokai , Ibaraki

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+24opu also on major surface soil components, Si02 and A1203. Major soil matrices contents in the deposits suggested that 5.1 % of the observed 239+24°Pu 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+24opu 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•Ey), respectively in 1979. Activity ratios o f 241/239+24opu changed widely. The average value of 0.066 was calculated from total amounts of each nuclides.