Analysis of cesium isotope compositions in environmental samples by thermal ionization mass spectrometry-3 Measurement of isotopic ratios of Cs in soil samples obtained in Fukushima prefecture

• Published in: Journal of nuclear science and technology Vol. 54; no. 2; pp. 158 - 166
• Main Authors: Shibahara, Yuji, Kubota, Takumi, Fujii, Toshiyuki, Fukutani, Satoshi, Takamiya, Koichi, Konno, Mitsuyuki, Mizuno, Satoshi, Yamana, Hajimu
• Format: Journal Article
• Language: English
• Published: Taylor & Francis 01.02.2017
• Subjects: activity ratio; Cesium; Cesium isotopes; Correlation; gamma spectrometry; Ionization; isotopic ratio; Mass spectrometry; Mathematical analysis; Nuclear accidents; Nuclear power generation; Nuclear power plants; soil sample; thermal ionization mass spectrometry
• ISSN: 0022-3131; 1881-1248
• DOI: 10.1080/00223131.2016.1223560

Cesium was recovered from soil samples obtained in Fukushima prefecture. Isotopic analysis of Cs was performed by γ-spectrometry to determine the activity ratio of 134 Cs/ 137 Cs and thermal ionization mass spectrometry was used to determine the isotopic ratios of 133 Cs/ 137 Cs and 135 Cs/ 137 Cs. The analytical results showed that both the activity ratio of 134 Cs/ 137 Cs and the isotopic ratio of 135 Cs/ 137 Cs were within the expected values for the Fukushima Daiichi Nuclear Power Plant estimated using the ORIGEN-II code, suggesting that most of the radioactive Cs in the soil sample originated from the Fukushima Daiichi Nuclear Power Plant. The concentration of 137 Cs and the contribution of radioactive Cs from global fallout were correlated to the distance from the Fukushima Daiichi Nuclear Power Plant, while the contribution of radioactive Cs from each reactor did not show any similar distance dependence.