measurement of UO concentration in molten NaCl-2CsCl by differential pulse voltammetry
Nagai, Takayuki ; Uehara, Akihiro*; Fujii, Toshiyuki*; Shirai, Osamu*; Yamana, Hajimu*
In order to assess the applicability of Differential Pulse Voltammetry technique to the measurement of UO concentration in the oxide electro-winning process, DPV measurements for UOCl in molten NaCl-2CsCl were studied. DPV measurement of UO in NaCl-2CsCl at 923 K, with a set of optimized parameters (potential sweep rate -0.1 V/s, pulse cycle 0.1 s, pulse width 10 ms, and pulse potential height 50 mV), showed a clear current peak at -0.9 V vs. Cl/Cl, and it was attributed to the reduction of UO to UO. The relation between the current peak height and the analytical concentration of the UO showed good proportionality in the concentration region up to 0.06 mol/, and the applicability of UO concentration measurement by DPV was confirmed up to 0.4 mol/. In order to assess the interference by the coexisting fission product elements to the measurement of UO concentration, DPV measurements of UO concentration in molten NaCl-2CsCl containing PdCl, NdCl, SmCl, and CeCl were performed also. Even before removing Pd, the current peak at -0.9 V vs. Cl/Cl by the reduction of UO to UO was found to be distinguishable from the reduction currents of Pd to Pd at -0.7 V vs. Cl/Cl. As a result, the applicability of DPV measurement technique to the monitoring of UO concentration in oxide electro-winning method is proposed.