Keywords:TRLFS, ultra-low temperature, uranium, chemical forms
Understanding of chemical forms of elements under various conditions is crucial to evaluate alternation of fuel debris during the decommissioning of the Fukushima Daiichi nuclear power plant or environmental behaviors of radionuclides relevant for nuclear waste disposal. In particular, time-resolved laser fluorescence spectroscopy (TRLFS) is a versatile technique for characterizing fluorescent metal ions such as U(VI), Cm(III), and Eu(III). The intensity and resolution of fluorescence spectra could be enhanced under near liquid helium temperature, which helps identify the chemical forms of ions in complicated environmental systems. In this presentation, we will present the development of such a ultra-low temperature TRLFS system equipped with liquid helium cryostat for high-sensitive analysis of these ions and report its application for different solid phases containing U(VI).