The vinyl radical in the ground vibronic state produced in a supersonic jet expansion by 193 nm excimer laser photolysis of vinyl bromide was investigated by millimeter-wave spectroscopy. Due to the proton tunneling, the ground state is split into two components, of which the lower and higher ones are denoted as 0+ and 0-, respectively. Eight pure rotational transitions with Ka = 0 and 1 obeying a-type selection rules were observed for each of the 0+ and 0- states in the frequency region of 60-250 GHz. Tunneling-rotation transitions connecting the lower (0+) and upper (0-) components of the tunneling doublet, obeying b-type selection rules, were also observed in the frequency region of 190-310 GHz, including three R- and six Q-branch transitions. The observed frequencies of the pure rotational and tunneling-rotation transitions were analyzed by using an effective Hamiltonian in which the coupling between the 0+ and 0- states was taken into account. A set of precise molecular constants was obtained. Among others, the proton tunneling splitting in the ground state was determined to be DeltaE0 = 16,272(2) MHz. The potential barrier height was estimated to be 1580 cm(-1) from the proton tunneling splitting, by an analysis using a detailed one-dimensional model. The spin-rotation and hyperfine interaction constants were also determined for the 0+ and 0- states together with the off-diagonal interaction constants connecting the 0+ and 0- states, epsilonab + epsilonba for the spin-rotation interaction and Tab for the hyperfine interaction of the alpha (CH) proton. The hyperfine interaction constants, due to the alpha proton and the beta (CH2) protons, are consistent with those derived from electron spin resonance studies.

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A previously reported emulsion flow (EF) extraction system does not equip the refining device for any used organic phase. Therefore, the processing of large quantities of wastewater by using the EF extractor alone could lead to the accumulation of extracted components into the organic phase, and a lowering of the extraction performance. In the present study, we developed an organic phase-refining-type EF system, which is equipped with a column for refining a used organic phase to prevent accumulation, and successfully applied it for treating uranium-containing wastewater.

The 126 Sn content in a spent nuclear fuel solution was determined by isotope dilution inductively coupled plasma mass spectrometry (ID-ICP-MS) for its inventory estimation in high-level radioactive waste. A well-characterized irradiated UO 2 fuel sample dissolved in a hot cell was used as a sample to evaluate the reliability of the methodology. Prior to the ICP-MS measurement, Sn was separated from Te ( 126 Te), which causes major isobaric interference in the determination of 126 Sn content, along with highly radioactive coexisting elements, such as Sr ( 90 Sr), Y ( 90 Y), Cs ( 137 Cs) and Ba ( 137m Ba), using an anionexchange column. The absence of counts attributed to Te at m/z = 125, 128, and 130 in the Sn-containing effluent (Sn fraction) indicates that Te was completely removed from the anion-exchange column. After washing, Sn retained on the column was readily eluted with 1 M HNO 3 accompanied with approximately 80% of the Cd and 0.03% of the U in the initial sample. Owing to the presences of Cd and U in Sn fraction, the measurements of 116 Sn and 119 Sn were affected by the isobaric 116 Cd and the doubly charged 238 U 2 + ion, resulting in the positive bias of the determined values. With the exception of the isotopic ratios including 116 Sn and 119 Sn, 117 Sn/ 126 Sn, 118 Sn/ 126 Sn, 120 Sn/ 126 Sn, 122 Sn/ 126 Sn and 124 Sn/ 126 Sn were successfully determined and showed good agreement with those obtained through ORIGEN2 calculations. The measured concentration of 126 Sn in the spent nuclear fuel sample solution was 0.74 ± 0.14 ng/g, which corresponds to 23.0 ± 4.5 ng per gram of the irradiated UO 2 fuel (excluding the presence of 126 Sn in the insoluble residue). The results reported in this paper are the first experimental values of 126 Sn content and isotope ratios in the spent nuclear fuel solution originating in spent nuclear fuel irradiated at a nuclear power plant in Japan.