Determination of long-lived radionuclide Cs in Cs adsorbent by LA-ICP-MS

Asai, Shiho*; Ohata, Masaki*; Hanzawa, Yukiko  ; Yomogida, Takumi   ; Horita, Takuma ; Kitatsuji, Yoshihiro  

A large amount of Cs adsorbents left over after decontamination of waste water has continued to accumulate in the Fukushima Daiichi Nuclear Power Plant. For safe disposal of such Cs adsorbents, estimation of the radioactivity is crucial. A long-lived beta emitting nuclide Cs which is captured in the Cs adsorbents along with a major radiation contributor Cs. Different from Cs which can be measured in gamma spectrometry, the activity of Cs is generally measured in liquid form, requiring elution of Cs. However, high radiation from the Cs adsorbents hampers the operations. In this study, we applied LA-ICP-MS which allows direct measurement of Cs adsorbent. With Cs /Cs given by LA-ICP-MS, Cs can be calculated by combining a measured Cs radioactivity. A radiocesium-containing sample was used to verify the proposed method. The results agreed well with those obtained through the measurement of Cs-separated solution.