11:45 AM - 12:00 PM
[MAG24-11] Uranium isotope ratio in Fukushima soil samples
Keywords:Fukushima soil sample, Uranium isotope, TIMS, 236U
We also measured Kobe and Okinawa soil samples before the accident as Global Fallout and geological standard sample as JSd-2 and NIST 4350b. Chernobyl and Kosovo samples were measured to notice artificial radioactive materials.
Soil samples were decomposed by a microwave (ETHOS one) digestion method with mixed acids after ashing. Uranium fraction from the dissolved sample was chemically separated by UTEVA-UTEVA resin chromatography to minimize interferences of Fe and Pb prior to isotope ratio measurement using TIMS and MC-ICP-MS.
Results of 235U/238U and 234U/238U ratio by TIMS and MC-ICP-MS couldn't reveal any significant difference between Fukushima soil samples and Global Fallout samples.
236U/238U detection limit of TIMS were considered by a standard solution from U ore and could be considered that was not under the influence of Global Fallout. We could measure 236U/238U ratio in U ore samples from 10-10~1.5×10-9 range. The yield for JSd-2 and NIST 4350b were noticed to be 4.2-7.8×10-8 and Kobe and Okinawa as an index of global atomic fallout were 6.5-9.8×10-9. The detailed results will be presented.