Development of a Rapid Analytical Method for 129I in the Contaminated Water and Tree Samples at the Fukushima Daiichi Nuclear Power Station

Abstract

The separation conditions for iodine species were investigated to analyze 129I in contaminated water and tree samples generated from the Fukushima Daiichi Nuclear Power Station (FDNPS). Inorganic iodine species in the samples from FDNPS were thought to be iodide (I−) and iodate (IO3 −); therefore, the behaviors of these species during separation using a solid-phase extraction sorbent, Anion-SR, for water samples and combustion for tree sample were studied. When the amount of I was 1 μg and used within a few hours, I− was extracted with the Anion-SR in 3 M NaOH and diluted HCl (pH 2) solutions, whereas IO3 − was only slightly extracted in these solutions. In contrast, 15 ng I− with a larger amount of IO3 − (1 μg I) in the diluted HCl (pH 2) and allowed to stand for 1 day was only slightly recovered. It is possibly that I− was changed to another species in a day in this condition. Iodate was successfully reduced to I− with NaHSO3 in the diluted HCl solution and extracted with the Anion-SR. Consequently, the solution condition to analyze both I− and IO3 − using Anion-SR was observed to be the diluted HCl at pH 2 with a reductant. For the tree samples, a combustion method was applied and the rate of temperature increase was optimized to avoid anomalous combustion. Greater than 90 % recovery was obtained for both I− and IO3 −, and the chemical species in the trap solutions was observed to contain I−.