• Membrane Journal
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• v.13 no.3
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• pp.154-161
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• 2003

We measured the permeation characteristics of water with the hydrophobic PTFE membranes dependent on water temperature to confirm the separation of oxygen isotopes using Air Gap Membrane Distillation (AGMD) and Vacuum Enhanced Membrane Distillation (VEMD). Isotopic concentrations of $H_2^{16}O$ and $H_2^{18}O$ of the permeated water vapor were measured by Diode Laser Absorption Spectroscopy. Concentrations of the heavy oxygen isotopes in the permeated water vapor were decreased. Isotope separation coefficients for the hydrophobic PTFE membranes were 1.004∼1.01 depending on the experimental conditions. We observed the effects of air in membrane pores on the oxygen isotope separation. Isotope separation coefficients for the hydrophobic PTFE membranes without air in pores are higher than those for the membrane with air in pores.

• Nuclear Engineering and Technology
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• v.55 no.9
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• pp.3291-3300
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• 2023

Recently molybdenum alloys have been introduced as accident tolerating materials for cladding of fuel rods. Molybdenum element has seven stable isotopes with different neutron absorption cross section used in various fields, including nuclear physics and radioisotope production. This study presents separation approaches for all intermediate isotopes of molybdenum element by squared-off cascades using a newly developed numerical code with Salp Swarm Algorithm (SSA) optimization algorithm. The parameters of cascade including feed flow rate, feed entry stage, cascade cut, input feed flow rate to gas centrifuges (GCs), and cut of the first stage are optimized to maximize both isotope recovery and cascade capacity. The squared off and squared cascades are studied, and the efficiencies are compared. The results obtained from the optimization showed that for the selected squared off cascade, Mo⁹⁴ in four separation steps, Mo⁹⁵ in five steps, Mo⁹⁶ in six steps, Mo⁹⁷ in seven steps, and Mo⁹⁸ in two steps are separated to the desired concentrations. The highest recovery factor is obtained 63% for Mo⁹⁴ separation and lowest recovery factor is found 45% for Mo⁹⁵.

• Nuclear Engineering and Technology
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• v.48 no.3
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• pp.719-726
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• 2016

The problem of separation of isotopes in a concurrent gas centrifuge is solved analytically for an arbitrary binary mixture of isotopes. The separative power of the optimised concurrent gas centrifuges for the uranium isotopes equals to ${\delta}U=12.7(V/700m/s)^2(300K/T)(L/1m)kg{\cdot}SWU/yr$, where L and V are the length and linear velocity of the rotor of the gas centrifuge and T is the temperature. This equation agrees well with the empirically determined separative power of optimised counter-current gas centrifuges.

• Bulletin of the Korean Chemical Society
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• v.22 no.5
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• pp.503-506
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• 2001

Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. One molar CH3COO Na solution was used as an eluent. The heavier isotope of lithium was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was calculated according to the method of Glueckauf from the elution curve and isotopic assays. The single stage separation factor of lithium isotope pair fractionation was 1.021.

• Bulletin of the Korean Chemical Society
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• v.22 no.6
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• pp.570-574
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• 2001

Magnesium isotope separation was investigated by chemical ion exchange with the 1-aza-12-crown-4 bonded Merrifield peptide resin using an elution chromatographic technique. The capacity of the novel azacrown ion exchanger was 1.0 meq/g dry resin. The heavier isotopes of magnesium were enriched in the resin phase, while the lighter isotopes were enriched in the solution phase. The single stage separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assys. The separation factors of $^{24}Mg^{2+}$-$^{25}Mg^{2+}$, $^{24}Mg^{2+}$-$^{26}Mg^{2+}$, and $^{25}Mg^{2+}$-$^{26}Mg^{2+}$ were 1.008, 1.019, and 1.006, respectively.

• Bulletin of the Korean Chemical Society
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• v.28 no.3
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• pp.451-456
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• 2007

Tetraazamacrocyclic ion exchangers tethered to Merrifield peptide resin (DTDM, TTTM) were prepared and the ion exchange capacity of these was characterized. The isotope separation of lithium was determined using breakthrough method of column chromatography. The isotope separation coefficient was strongly dependent on the ligand structure by Glueckauf's theory. We found that the isotope separation coefficients were increased as the values of distribution coefficients were increased. In this experiment the lighter isotope, 6Li was enriched in the resin phase, while the heavier isotope, 7Li in the solution phase. The ion radius of lighter isotope, 6Li was shorter than the heavier isotope, 7Li. The hydration number of lithium ion with the same charge became small as mass number was decreased. Because 6Li was more strongly retained in the resin than 7Li, the isotopes of lithium were separated with subsequent enrichment in the resin phase.

• Journal of Radiopharmaceuticals and Molecular Probes
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• v.7 no.2
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• pp.69-77
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• 2021

No-carrier-added holmium-166 (n.c.a ¹⁶⁶Ho) separation is performed based on the results of separation conditions using stable isotopes dysprosium (Dy) and holmium (Ho) to minimize radioactive waste from separation optimization procedures. Successful separation of two adjacent lanthanides was achieved by cation-exchange chromatography using a sulfonated resin in the H+ form (BP-800) and α-hydroxyisobutyric acid (α-HIBA) as eluent. For the identification process after separation of stable isotopes, the use of chromogenic reagents alternatively enables on-line detection because the lanthanides are hardly absorb light in the UV-vis region or exhibit radioactivity. Four different chromogenic reagents were pre-tested to evaluate suitable coloring reagents, of which 4-(2-Pyridylazo)resorcinol is the most recommendable considering the sensitivity and specificity for lanthanides. Lanthanide radioisotopes (RI) were monitored for separation with an RI detector using a lab-made separation LC system. Under the proper separation conditions, the n.c.a ¹⁶⁶Ho was effectively obtained from a large amount of 100 mg dysprosium target within 2 hrs.

• Journal of the Korean Chemical Society
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• v.45 no.3
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• pp.219-222
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• 2001

Separation of lithium isotopes was investigated by chemical ion exchange with a hydrous manganese(IV) oxide ion exchanger using an elution chromatography. The capacity of manganese(IV) oxide ion exchanger was 0.5 meq/g. The heavier lithium isotope was enriched in the solution phase, while the lighter isotope was enriched in the ion exchanger phase. The separation factor was determined according to the method of Glueckauf from the elution curve and isotopic assays. The separation factor of $^6Li^+$-$^7Li^+$ isotope pair fractionation was 1.018.

• Nuclear Engineering and Technology
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• v.52 no.12
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• pp.2867-2873
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• 2020

In reprocessed uranium, derived from an impoverished fuel of light-water moderated reactors, there are isotopes of ^{232, 234, 236}U, which make its recycling remarkably difficult. A method of concentration of ²³⁵U target isotope in cascade's additional product was proposed to recover the isotopic composition of reprocessed uranium. A general calculation procedure is presented and a parameters' optimization of multi-flow cascades with additional products. For the first time a numeric model of a cascade that uses the cuts of partial flows of stages with relatively high separation factors was applied in this procedure. A novel computing experiment is carried out on separation of reprocessed uranium hexafluoride with providing a high concentration of ²³⁵U in cascade's additional product with subsequent dilution. The parameters of cascades' stages are determined so as to allow reducing the ^{232, 234, 236}U isotope content up to the acceptable. It was demonstrated that the dilution of selected products by the natural waste makes it possible to receive a low enriched uranium hexafluoride that meets the ASTM C996-15 specification for commercial grade.

• Journal of the Korean Chemical Society
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• v.27 no.3
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• pp.189-193
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• 1983

The lithium isotopes separation experiments were carried out in hydrochloric acid with cation exchanger systerns. In these experiments were employed porous sulfonated styrene-divinylbenzene copolymer and Dowex 50w-x8 as cation exchanger. The contents of lithium of the fraction were determined with atomic absorption spectrophotometer. The relative mass of lithium isotopes of the fractions was analyzed on a mass spectrometer. The isotope separation factors of lithium were calculated from the isotope compositions of these eluted fractions. Separation factor for the system in hydrochloric acid and porous sulfonated styrene-divinylbenzene copolymer was found to be 1.0020, and for the case of system in hydrochloric acid and Dowex 50w-x8 was 1.0011${\om}$0.0002. From these results, we found that the separation factor for porous sulfonated styrene-divinylbenzene copolymer ionexchanger is larger than value of Dowex 50w-x8 ionexchanger.