Measurement of uranium isotope ratios in Fukushima-accident contaminated soil samples using multi collector inductively coupled plasma mass spectrometry

• Published in: Journal of environmental radioactivity Vol. 232; p. 106568
• Main Authors: Murugan, R., Kavasi, N., Sahoo, S.K., Omori, Y., Sorimachi, A., Takahashi, H., Aono, T.
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.06.2021
• Subjects: 137Cs; 234U/238U activity ratio; 235U/238U; atomic absorption spectrometry; cesium radioisotopes; Cesium Radioisotopes - analysis; FDNPS; Fukushima Nuclear Accident; Fukushima soils; isotope dilution technique; isotopes; Japan; Mass Spectrometry; MC-ICP-MS; nuclear power; Plasma - chemistry; polluted soils; power plants; Radiation Monitoring; radioactivity; Soil; Soil Pollutants, Radioactive - analysis; uranium; Uranium - analysis; Japan; 235U/238U; FDNPS; 234U/238U activity ratio; Fukushima soils; MC-ICP-MS; 137Cs; Cs; U/U; U/U activity ratio
• ISSN: 0265-931X; 1879-1700; 1879-1700
• DOI: 10.1016/j.jenvrad.2021.106568

In the present study, 137Cs and 238U activity concentrations, 234U/238U activity ratio, and 235U/238U isotope ratio were measured in fifteen soil samples collected from the exclusion zone around the Fukushima Daiichi Nuclear Power Station (FDNPS). The 137Cs activity concentrations of Fukushima-accident contaminated soil samples ranged from 29.9 to 4780 kBq kg−1 with a mean of 2007 kBq kg−1. On the other hand, the 238U activity concentrations of these soil samples ranged from 5.2 to 22.4 Bq kg−1 with a mean of 13.2 Bq kg−1. The activity ratios of 234U/238U ranged from 0.973 to 1.023. The 235U/238U isotope ratios of these exclusion zone soil samples varied from 0.007246 to 0.007260, and they were similar to the natural terrestrial ratio confirming the natural origin. Using isotope dilution technique, the 235U/137Cs activity ratio was theoretically estimated for highly 137Cs contaminated soil samples from Fukushima exclusion zone ranged from 5.01 × 10−8 - 6.16 × 10−7 with a mean value of 2.51 × 10−7. •137Cs activity concentration ranged from 29.9 to 4780 kBq kg−1.•The activity ratio of 234U/238U were in the range of 0.973–1.023.•The 235U/238U isotope ratios indicate natural in origin for Fukushima soil samples.•The 235U/137Cs activity ratio ranged from 5.01 × 10−8 - 6.16 × 10−7 for Fukushima exclusion zone soil samples.