@misc{oai:repo.qst.go.jp:00083711,
 author = {Kasar, Sharayu and Sorimachi, Atsuyuki and Omori, Yasutaka and Aono , Tatsuo and Kumar Sahoo, Sarata and Kasar, Sharayu and Tatsuo, Aono and Sahoo, Sarata},
 month = {Sep},
 note = {The behaviour of actinides after Fukushima Dai-ichi Nuclear Power Station (FDNPS) accident in the environment is still unclear. An abundant information on radio cesium activity is available in literature, however a few reports are available on activity concentration and isotopic ratios of U and Pu in the soil samples affected due to FDNPS accident. MOX was used as nuclear fuel in the reactors. From the viewpoint of radiation protection due to nuclear accident, it is crucial to obtain sufficient data on U and Pu radioisotopes. Measurement of 236U/238U and 238Pu/137Cs ratios in soil samples could be used as tracers to identify source of contamination due to nuclear accident.

In the present work, soil samples were collected from Okuma town within <5 km distance from FDNPS. The 137Cs activity concentration ranged from 160 to 5600 Bq/g in soils. The isotope ratios of 234U/238U, 235U/238U and 236U/238U ratios were measured simultaneously using thermal ionization mass spectrometer (TIMS). 238Pu activity concentration was measured in the same soil samples using alpha spectrometry. 

In this study, highest Pu activity concentration was 0.05 +/- 0.004 Bg/kg with radio cesium activity of ~450 Bq/g. The highest activity concentration of 238Pu in Fukushima prefecture soil has been reported as 0.092 Bg/kg. The value for 236U/238U varies from (10e-9-10e-7) in samples from the present study. This shows heterogeneous mixing effect of global fallout and FDNPS accident. The relation of 134Cs and 137Cs activity as well as with U and Pu ratios will be presented in the meeting., Environmental Dynamics of Radionuclides and Biological Effects of Low Dose-Rate Radiation},
 title = {Behaviour of 238Pu and 236U isotopes in soil samples affected due to FDNPS accident},
 year = {2021}
}