Determination of trace constituents in thoria by laser induced breakdown spectrometry

Trace constituents were determined in thorium oxide powder using laser induced breakdown spectrometry (LIBS). Thoria powder was pressed into a pellet prior to LIBS analysis. The optimum laser energy and delay time were determined to be about 50 mJ energy and 6 μs, respectively, for thoria analysis. Calibration curves were obtained for seven impurities (Mg, Al, Ca, Ni, Fe, Cu and Mo) with thoria certified reference materials (CRM) prepared and supplied by nuclear fuel complex, Hyderabad, India. The results obtained by LIBS were found to be in good agreement with the certified values for the trace impurities. The LIBS technique provides an independent approach for impurities determination in thoria without any dissolution or removal of bulk of thorium.