• Journal of environmental and Sanitary engineering
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• v.14 no.3
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• pp.80-89
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• 1999

The ion exchange resins have been synthesized from chlormethyl styrene-1,4-divinyl benzene(DVB) with 1%, 5%, and 10%-crosslinking and macrocyclic ligand of cryptand type by copolymerization method and the adsorption characteristics of uranium(VI), lead(II) and holmium(III) ions have been investigated in various experimental conditions. The correlation between the adsorption characteristics of rare earths and transition metal on the resins and stability constants of complexes with macrocyclic ligand have been examined. The $UO_2^{2+}$ aqueous solutions are not adsorbed on the resins below pH 3.0, but the power of adsorption of $UO_2^{2+}$ increased rapidly above pH 4.0. The adsorption power was in the order of 1%, 10%, and 5%-crosslinked resin, but adsorptive characteristics of resins decreased in proportion to the order of dielectric constants of solvents.

• Journal of Integrative Natural Science
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• v.10 no.1
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• pp.43-50
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• 2017

Synthetic resins were combined 1-aza-12-crown-4 macrocyclic ligand with styrene divinylbenzene copolymer having 1%, 2%, 8%, and 16% crosslink by a substitution reaction. These synthetic resins were confirmed by chlorine content, elementary analysis, SEM, surface area, and IR-spectrum. As the results of the effects of pH, crosslink of synthetic resin, and dielectric constant of a solvent on metal ion adsorption for resin adsorbent, the metal ions showed high adsorption at pH 3 or over. Adsorption selectivity for the resin in ethanol solvent was the order of uranium ($UO_2{^{2+}}$) > cobalt ($Co^{2+}$) > dysprosium ($Dy^{3+}$) ion, adsorbability of the metal ion was the crosslink in order of 1%, 2%, 8%, and 16% and it was increased with the lower dielectric constant. In addition, theses metal ions could be separated in the column with 1% crosslink resin by using nitric acid (pH 2.0) as an eluent.

• Nuclear Engineering and Technology
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• v.50 no.7
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• pp.1112-1119
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• 2018

Dicalcium phosphate nanoparticles (DCP-NPs) was synthesized chemically and used for adsorptive removal of uranyl ions from aqueous solutions in a batch system. A commercial grade of DCP (monetite) was also employed for comparison. The synthesized and commercial adsorbents (S-DCP and C-DCP) were characterized by FT-IR, SEM and XRD techniques. The investigation of adsorption isotherms indicated that the maximum adsorption capacities ($q_m$) for C-DCP and S-DCP were 714.3 and $666.7mg\;g^{-1}$ (at 293 K), respectively. The experimental kinetics were well-described by the pseudo-second-order kinetic and the equilibrium data were fitted with both Langmuir and Freundlich adsorption models. Thermodynamic studies indicated that the adsorption of uranyl ions on the monetite surface was a spontaneous exothermic process. The exhausted adsorbents could be regenerated by washing with $0.10mol\;L^{-1}$ NaOH.

• Nuclear Engineering and Technology
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• v.31 no.4
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• pp.401-407
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• 1999

We have performed two experiments in the fast critical assembly BFS to measure the effective delayed neutron fraction $\beta$$_{eff}$ values and compared the results to validate the $\beta$$_{eff}$ computation code, BETA-K. Measurements of $\beta$$_{eff}$ were carried out in a metallic plutonium core and a metallic uranium core with Cf$^{252}$ source pseudo-reactivity method. Fission integrals and correction factors, which were used to obtain the experimental $\beta$$_{eff}$ values, were calculated by using the LMR core design computation code system of KAERI. BETA-K has been developed consistently with the hexagonal Nodal Expansion Method (NEM) and it used delayed neutron data of ENDF/B-VI. By comparing the computed $\beta$$_{eff}$ values with the measured ones, we found that the results from BETA-K agreed with the experimental values within the experimental error bound.ror bound.

• Nuclear Engineering and Technology
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• v.56 no.1
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• pp.34-41
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• 2024

This work presents experimental data and modelling of the release of Mo from high-burnup spent nuclear fuel (63 MWd/kgU) at two different pH values, 8.4 and 13.2 in air. The release of Mo from SF to the solution is around two orders of magnitude higher at pH = 13.2 than at pH = 8.4. The high Mo release at high pH would indicate that Mo would not be congruently released with uranium and would have an important contribution to the Instant Release Fraction, with a value of 5.3%. Parallel experiments with pure non irradiated Mo(s) and XPS determinations indicated that the faster dissolution at pH = 13.2 could be the consequence of the higher releases from metallic Mo in the fuel through a surface complexation mechanism promoted by the OH^- and the oxidation of the metal to Mo(VI) via the formation of intermediate Mo(IV) and Mo(V) species.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.8 no.4
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• pp.347-353
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• 2010

Source terms of metal waste comprising a spent fuel assembly are relatively important when the spent fuel is pyroprocessed, because cesium, strontium, and transuranics are not a concern any more in the aspect of source term of permanent disposal. In this study, characteristics of radiation source terms for each structural component in spent fuel assembly was analyzed by using ORIGEN-S with a assumption that 10 metric tons of uranium is pyroprocessed. At first, mass and volume for each structural component of the fuel assembly were calculated in detail. Activation cross section library was generated by using KENO-VI/ORIGEN-S module for top-end piece and bottom-end piece, because those are located at outer core with different neutron spectrum compared to that of inner core. As a result, values of radioactivity, decay heat, and hazard index were reveled to be $1.40{\times}10^{15}$ Bequerels, 236 Watts, $4.34{\times}10^9m^3$-water, respectively, at 10 years after discharge. Those values correspond to 0.7 %, 1.1 %, 0.1 %, respectively, compared to that of spent fuel. Inconel 718 grid plate was shown to be the most important component in the all aspects of radioactivity, decay heat, and hazard index although the mass occupies only 1 % of the total. It was also shown that if the Inconel 718 grid plate is managed separately, the radioactivity and hazard index of metal waste could be decreased to 20~45 % and 30~45 %, respectively. As a whole, decay heat of metal waste was shown to be negligible in the aspect of disposal system design, while the radioactivity and hazard index are important.