In-line Gas Analyzer for UF6and F2through Differential Thermal Conductivity Measurements

Abstract

For the purpose of analyzing UF6 and F2 continuously in the fluorination of U, a system of differential thermal conductivity cells (TCC), equipped with shock absorber, and also NaF and KCl traps, has been trially constructed. Mixed flow-through/diffusion type katharometers are used, provided with four and two Ni filaments (∼30Ω) on the UF6 and F2 cells, respectively. Based on data obtained from preliminary operating tests, the standard conditions for operating the system were established i.e., 500 mmHg abs. Cell pressure, 200 ml/min flow rate and 80 mA bridge current. Under these operating conditions and for UF6 and F2 concentrations of 2 and 20 v/o respectively, the overall out-put variations are below 1%. The total response time of the system including the transport lag is below 1 and 2.5 min for UF6 and F2 cells, respectively. The dead time due to blow-back noise is observed to have about the same period as the above response time. The sensitivities for UF6 and F2 are found respectively to be 11.5 and 0.37 mV/v/o, for which the limits of analytical determination are 0.01 and 0.05 v/o;, respectively. By practical application to uranium fluorination, the TCC system thus devised, has proven to possess the requisite characteristics for measurements of reaction rate, fluorine utilization and end of reaction in fluid-bed fluorination of uranium oxides. The system has possibilities of application to the study of reaction steps.