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The field of radiochemistry in the Republic of Korea has expanded greatly over the last three decades to meet the rapid growth of technological demands in various areas such as nuclear energy and nuclear technologies for human health and environmental protection. Major research activities, which were initially centered at the Korea Atomic Energy Research Institute (KAERI), have gradually spread to major universities and the commercial sector. In this review, progress and recent research trends in nuclear and radiochemistry in Korea are summarized. The main research outcomes achieved by KAERI scientists are highlighted, with emphasis on basic actinide chemistry in nuclear fuel cycles, the radioanalytical chemistry of various radionuclides from radioactive waste and the environment, and medical radionuclide production. In addition, recent efforts to promote radiochemical education and future perspectives are briefly outlined.

Environmental damage from serious nuclear accidents should be urgently restored, which needs the removal of radioactive species. Radioactive iodine isotopes are particularly problematic for human health because they are released in large amounts and retain radioactivity for a substantial time. Herein, we prepare platinum-coated iron nanoparticles (Fe@Pt) as a highly selective and reusable adsorbent for iodine species, i.e., iodide (I

We have developed a liquid level measurement system using the dynamic bubbler technique. Based on our previous methodology, herein, we established a field-applicable wireless measurement system to simultaneously monitor the liquid level and density of corrosive molten salts at high temperatures. The accuracy and precision of the present technique were suitable for applications in harsh field processes. Regardless of the base pressure under the present experimental conditions, percentage differences compared with reliable reference values in the literature were less than 10% in the temperature range 773–1123 K using KNO3 as a molten salt. Our dynamic bubbler technique produces an average percentage difference ca. 5–8% with a standard deviation of less than ca. 0.04 g cm−3 between measured and literature density values in all experiments, whereas the standard deviations in all liquid level measurements were less than 0.3 mm (0.07% relative standard deviation). The present technique is an excellent alternative to many conventional liquid level and density measurement techniques used under extreme environmental conditions characteristic of common industrial processes.

We demonstrated that bromine in ethyl acetate can selectively separate metallic contents in lanthanide metal-oxide mixtures for analysis, which had been validated for uranium. This Br2-EtOAc dissolution method was applied to determine the constituents of metal and metal oxide in SIMFuel that was electrochemically reduced from oxide fuel in the molten salt. Compared with the analysis results obtained after dissolving the fuel in an acid solution, we concluded that the Br2-EtOAc method can be applied to uranium and rare earths but not to noble metals for the reduction yield determination.

Co-electrodeposition of uranium and molybdenum from a LiCl-KCl melt was investigated using cyclic voltammetry (CV), scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), and X-ray diffraction (XRD). The electrochemical study showed that the electrodeposition of Mo occurred from a molten LiCl-KCl eutectic at potentials more negative than −0.3 V vs. Ag|Ag+. Electrodeposition at a low overpotential range (between −0.3 V and −0.35 V) resulted in flat, thin Mo films, whereas greater overpotentials led to the growth of 3D films. Conditions for simultaneous electrodeposition of U and Mo were then optimized by varying the concentrations of UCl3 and MoCl3 and the electrodeposition method applied. At a constant potential of −1.58 V, a melt containing 1.3 wt% UCl3 and 1.5 wt% MoCl3 resulted in the co-electrodeposition of dendrites due to the high overpotential for Mo electrodeposition. However, diffusion-controlled electrodeposition using the same potential and concentration resulted in a uniform and flat U-Mo film. This co-electrodeposition of U-Mo films could be applied to the preparation of low-cost U-Mo nuclear fuel.

We report the synthesis and excited-state dynamics of a bis[p-ethynyldithiobenzoato]Pd(II)-bridged bis[(porphinato) zinc(II)] complex (PZn–Pd(edtb)2–PZn) that exhibits unusual solvent dielectric (e)-dependent excited-state relaxation behavior. In nonpolar toluene solvent, PZn–Pd(edtb)2–PZn manifests an ultrafast S1 → T1 intersystem crossing time constant (τISC ≈ 2 ps), a broad, high-oscillator strength T1 → Tn transient absorption manifold (λmax(T1 → Tn) = 940 nm), and a near unity triplet-state formation quantum yield (ΦT ≈ 1; τT = 2.2 μs). In contrast, in moderately polar solvents (e.g., dichloromethane (DCM) or THF), the S1 → T1 intersystem crossing quantum yield is significantly suppressed (ΦT ≈ 0.2; τF ≈ 60 ps in DCM). Comparative femtosecond transient absorption studies in DCM and mixed DCM/toluene solvent systems reveal a new low-energy stimulated emission signal, the λmaxem of which is highly sensitive to solvent polarity. The lack of spectral signatures for radical species, and the emergence of intense stimulated emission indicate an additional low energy electronically excited-state (S*), populated via S1-state relaxation, that also possesses substantial singlet character. As solvent polarity is progressively increased, the energy of S* progressively decreases, eventually becoming lower than the S1 state and providing an excited-state relaxation channel that bypasses T1 state formation. These data show that the nature of the PZn–Pd(edtb)2–PZn excited-state dynamics is strongly influenced by the solvent dielectric, and that this Pd(II)-based linker motif offers new opportunities to engineer excited-state spin distributions and lifetimes in strongly conjugated chromophore assemblies.

An in-house manufactured liquid level measurement system based on dynamic tube pressure measurements was established for high-temperature corrosive molten salts. The accuracy and precision of the present technique depend on the furnace temperature, initial base tube pressure, and tube speed. Whereas the initial base tube pressure did not influence the performance of the measurements significantly, a set value of the critical pressure level for the detection of the liquid surface was an important factor, especially in case of the higher temperature experiments. Within a temperature range of 773–1073 K using KNO 3 , our technique could obtain a measurement error of less than ca. 0.05 mm in precision. The tube speed increased from 0.25 mm s −1 to 2.00 mm s −1 , resulting in a % departure of only 1.1%, 1.3%, and 1.9% at 773 K, 973 K, and 1073 K, respectively. The measurement of travel distance instead of measuring the liquid level is useful in terms of the calibration-free process monitoring. The gravimetric calibration method was also used to determine the total mass of the liquid, where the weight versus travel distance calibration curves showed an excellent linearity with R 2 = 0.9999 under all temperature conditions.

Modern megacities around the world are exemplified by extraordinary population densities, ground transportation omnipresence, and breathtakingly busy airports that operate day and night. And while airports act as critical city infrastructures from economic, employment, and transportation perspectives, assessing noise resulting from the constancy of flyover aircraft is challenging, in part due to the lack of noise measurements. Additionally, community noise reporting yield mostly qualitative data which further renders community noise assessment difficult. Citygram, in partnership with GetNoisy, employs a socio-technical model to enable the creation of data-driven, community-accessible spatio-temporally granular airplane noise maps. The technology layer is comprised of edge compute sensor devices, cloud server, and web-based user dashboard that automatically identifies, tracks, and tags airplane events with timestamps, decibel levels, 3D positions, tail numbers, and speed. The social layer enables community engagement and facilitates rapid sensor network scaling. This socio-technical airplane soundmapping model, we believe, can be applied to practically any neighborhood as it harnesses and integrates state-of-the-art smart noise sensing technologies, environmentally incentivized communities, existing community resources, and participation workflows that are necessary in rendering a scalable and cost-effective airplane noise soundmapping system.