An Overview on Advancement in Different Technologies for the Measurement of Uranium in Diverse Matrices

Uranium in significant concentrations may be transported throughout a wide range of Eh and pH conditions as various uranyl complexes. An overview of advancement in different technologies, which can be used in the field as well as in a laboratory for the measurement of uranium in diverse matrices such as water, minerals, mineralized rocks, and other beneficiation products for its exploration and processing industries is presented. Laser-based technologies, ion chromatography, micro-sample X-ray analysis method followed by energy dispersive X-ray fluorescence technique (MXA-EDXRF), sensors for electrochemical detection followed by cyclic voltammogram and alpha liquid scintillation counting techniques are the most promising techniques. Among these techniques, laser/LED-fluorimetry/spectrofluorimetry, in particular, is the technique of choice because of its high-performance qualification (PQ), inherent sensitivity, simplicity, cost-effective, minimum generation of analytical waste, rapidity, easy calibration and operation. It also fulfills the basic essential requirements of reliability, applicability and practicability (RAPs) for the analysis of uranium in a solution of diverse matrices in the entire nuclear fuel cycle. A very extensive range of uranium concentrations may be covered. Laser/LED- fluorimetry is suitable for direct determination of uranium in natural water systems within the mg L-1 and mg L-1 range while differential technique in laser/LED- fluorimetry (DT-LIF) is suitable for mineralized rocks and concentrates independent of matrix effects (uranium in samples containing >0.01% uranium). The most interesting feature of TRLIF is its capability of performing speciation of complexes directly in solution as well as remote determination via fiber optics and optrode. Future trends and advances in lasers, miniaturization and automation via FIA have been discussed. Application of differential technique (DT) in laser-induced/LED-fluorimetry for the direct determination of uranium (without resorting to any separation technique) is recommended for routine accurate determination of uranium over a wide range of concentrations, which is based on the comparison of the response of the standard with a sample of similar but unknown concentration on the same sample weight basis. In this approach, the procedure of elimination of interference by simple dilution of the sample has the distinct advantage of being quick and very simple to perform because it does not require any chemical preparation or extraction. The results are in good agreement with the published data and those obtained by conventional fluorimetry and other methods, and of comparable precision to those obtained by titrimetric assay. It is a self-standardized green methodology of measurement and guarantees the quality of an analytical result (Accuracy, high precision, reliability, comparability, and traceability). Application of differential technique in Laser-induced/LED-fluorimetry has the inherent high metrological quality and will be useful for the analysis of uranium in ores, certification of reference materials, borehole core assay, beneficiation product, and other diverse applications in the entire nuclear fuel cycle worldwide. Over the years, the LED-fluorimetry technique has emerged with so many analytical figures of merit and will continue to grow for reliable measurement of uranium in water as well as for rocks, minerals, concentrates and other diverse matrices to fulfill the mission and mandate for the sustainable growth of the nuclear industry worldwide.