• Nuclear Engineering and Technology
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• v.41 no.1
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• pp.99-106
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• 2009

The contents of transuranic elements ($^{237}Np$, $^{238}Pu$, $^{239}Pu$, $^{240}Pu$, $^{241}Am$, $^{244}Cm$, and $^{242}Cm$) in high-burnup spent fuel samples ($35.6{\sim}53.9\;GWd/MtU$) were determined by alpha spectrometry. Anion exchange chromatography and diethylhexyl phosphoric acid extraction chromatography were applied for the separation of these elements from the uranium matrix. The measured values of the nuclides were compared with ORIGEN-2 calculations. For plutonium, the measurements were higher than the calculations by about $2.6{\sim}32.7%$ on average according to each isotope, and those for americium and curium were also higher by about $35.9{\sim}63.1%$. However, for $^{237}Np$, the measurements were lower by about 52% on average for the samples.

• Nuclear Engineering and Technology
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• v.54 no.10
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• pp.3650-3659
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• 2022

We proposed a modification of a double cascade scheme to enrich reprocessed uranium. Such a cascade scheme represents a combination of one cascade with "broadening" of the flow and an ordinary three-flow cascade. A calculation and optimization method has been developed for the proposed scheme according to various efficiency criteria. It is shown that the proposed scheme makes it possible to obtain low-enriched uranium of commercial quality using reprocessed uranium of different initial compositions. For example, the enrichment of reprocessed uranium, which had gone through five consequent recycles, was considered. The proposed scheme allowed to enrich it with simultaneous fulfillment of restrictions on isotopes ²³²U, ²³⁴U, and ²³⁶U. Such results indicate the scheme's applicability under conditions of multiple recycling of uranium in reactor fuel. Computational experiments have shown that in the proposed modification, a noticeable saving of natural uranium in the cycle (~18%) can be achieved, provided that the additional consumption of separative work does not exceed 10%, compared with the case of enrichment of natural uranium to obtain LEU of equivalent quality.

• Nuclear Engineering and Technology
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• v.55 no.1
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• pp.378-390
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• 2023

The SPES (Selective Production of Exotic Species) facility, currently under development at Legnaro National Laboratories of INFN, aims at the production of intense RIB (Radioactive Ion Beams) employing the Isotope Separation On-Line (ISOL) technique for interdisciplinary research. The radioactive isotopes of interest are produced by the interaction of a multi-foil uranium carbide target with a 40 MeV 200 μA proton beam generated by a cyclotron proton driver. The Target Ion Source (TIS) is the core of the SPES project, here the radioactive nuclei, mainly neutron-rich isotopes, are stopped, extracted, ionized, separated, accelerated and delivered to specific experimental areas. Due to efficiency reasons, the TIS unit needs to be replaced periodically during operation. In this highly radioactive environment, the employment of autonomous systems allows the manipulation, transport, and storage of the TIS unit without the need for human intervention. A dedicated remote handling infrastructure is therefore under development to fulfill the functional and safety requirement of the project. This contribution describes the layout of the SPES target area, where all the remote handling systems operate to grant the smooth operation of the facility avoiding personnel exposure to a high dose rate or contamination issues.

• Analytical Science and Technology
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• v.14 no.4
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• pp.291-299
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• 2001

A method of separation and purification of Sm for quantitation of Sm isotopes from various fission products in PWR spent nuclear fuels has been studied. Simulated solution containing inactive metal ions(Cs, Ba, Gd, Eu, Sm and Nd) in place of radioactive fission products was prepared. Sm was separated with 0.5 M $HNO_3$/80% MeOH after washing with 1 M $HNO_3$/90% MeOH on AG $1{\times}8$, anion exchange resin. Sm was purified on cation exchange resin, AG $50W{\times}8$, pretreated with 0.2 M alpha-hydroxisobutyric acid(pH 4.5-4.6) to remove Ba causing isobaric effect Sm from PWR spent fuel. As a result of mass spectrometric measurement, eluted Sm portion did not include isobars form other elements such as Gd, Eu, Pm, Nd and BaO. The contents of Sm and its isotopes($^{147}Sm$, $^{148}Sm$, $^{149}Sm$, $^{150}Sm$, $^{151}Sm$, $^{152}Sm$ and $^{154}Sm$) in spent fuel were determined by isotope dilution mass spectrometric method spiking $^{154}Sm$.

• Analytical Science and Technology
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• v.21 no.5
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• pp.364-374
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• 2008

Antarctic Environmental Monitoring Handbook' was published by COMNAP/SCAR in 2000. The standardized method described in this handbook is recommended for monitoring of antarctic environment. High pressure bomb technique in this guide was used to decompose soil samples. In compliance with this guide book, high pressure bomb technique was applied to decompose the antarctic soil sampled at the King Sejong Station. An Isotope Dilution-Inductively Coupled Plasma-Mass Spectrometry (ID-ICP-MS) was applied to determine mass concentrations of Pb, Cu and Zn in the soil. The accuracy in this method was verified by the analysis of certified reference materials (CRM) of NIST 2702 (marine sediment). The analytical results agreed with certified value within the range from 99.5~100.8%. Matrix separation was necessitated for the determination of Cu and Zn by Chelex 100 ion exchange resin. As a result, the average mass concentrations of Pb, Cu and Zn which are suspected to be caused by anthropogenic pollution were 332.9 mg/kg, 95.6 mg/kg and 115.3 mg/kg, respectively. Those for the metals sampled in the soils of the remote regions from the station were 28.1 mg/kg, 101.8 mg/kg and 115.6 mg/kg, respectively.

• The Korean Journal of Petroleum Geology
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• v.13 no.1
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• pp.24-29
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• 2007

The main purpose of this study is to identify the shallow gas origin in the KSSM zone. Based on the results of gas composition and isotope in the headsapace gas, the shallow gas is mainly composed of methane and carbon and deuterium isotopes (${\delta}^{13}CCH_4$ and ${\delta}DCH_4$) of methane has ranged from -93.4%o to -70.9%, and from -228%o to -199%o in each. These results imply that shallow gas has predominately biogenic source by $CO_2$ reduction rather than thermogenic. The carbon isotopic separation (${\varepsilon}_c$) between methane and carbon dioxide $(CO_2)$ has a range of 54.4 to 72.2, it also supports biogenic origin of shallow gas.

• Nuclear Engineering and Technology
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• v.52 no.7
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• pp.1517-1523
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• 2020

The widely used medical isotope technetium-99 m (^99mTc) is a daughter of Molybdenum-99 (⁹⁹Mo), which is mainly produced using dedicated research reactors from the nuclear fission of uranium-235 (²³⁵U). ^99mTc has been used for several decades, which covers about 80% of the all the nuclear diagnostics procedures. Recently, the instability of the supply has become an important topic throughout the international radioisotope communities. The aging of major ⁹⁹Mo production reactors has also caused frequent shutdowns. It has triggered movements to establish new research reactors for ⁹⁹Mo production, as well as the development of various ⁹⁹Mo production technologies. In this context, a new research reactor project was launched in 2012 in Korea. At the same time, the development of fission-based ⁹⁹Mo production process was initiated by Korea Atomic Energy Research Institute (KAERI) in 2012 in order to be implemented by the new research reactor. The KAERI process is based on the caustic dissolution of plate-type LEU (low enriched uranium) dispersion targets, followed by the separation and purification using a series of columns. The development of proper waste treatment technologies for the gaseous, liquid, and solid radioactive wastes also took place. The first stage of this process development was completed in 2018. In this paper, the results of the hot test production of fission ⁹⁹Mo using HANARO, KAERI's 30 MW research reactor, was described.

• Nuclear Engineering and Technology
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• v.14 no.2
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• pp.78-85
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• 1982

The steady-state rotation of plasma centrifuge is theoretically analyzed to understand the physics of rotating plasmas and its feasibility for isotope separation. The centrifuge system under consideration consists of an annular gap between coaxial cylindrical anode and cathode in the presence of an externally-applied axial magnetic field. A problem for coupled partial differential equations describing centrifuge fields is formulated on the basis of the magnetohydrodynamic equations. Two-dimensional solutions are found analytically in the form of Fourier-Bessel series. The current density and velocity distributions are discussed in terms of the Hartmann number and the geometrical parameter of the system. At typical conditions, rotational speeds of the plasma up to the order of 10$^4$m/sec are achievable, and increase either with increasing Hartmann number, or with increasing ratio of the axial length to the inner radius of the cylinder. In view of much higher speeds of rotation which can be achieved in plasma centrifuge, it is expected that its efficiency is superior to mechanically driven gas centrifuges.

• Journal of the Korean Chemical Society
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• v.27 no.4
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• pp.279-286
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• 1983

An apparatus was made for the electrodeposition of alpha emitting actinide nuclides, $^{207}Bi$ and $^{210}Po$. The electrodeposition was made on a polished stainless steel plate cathode. The anode was made of platinum wire and to stir the solution. With the ammonium chloride as electrolyte initial pH = 4, chloride concentration = 0.6M and solution volume = 15ml, a current of 1.5 ampere(current density = 0.59A/$cm^2$) was flowed for 100 minutes for the quantitative recovery of electrodeposition and on average recovery of 98.3% was obtained within ${\pm}$0.7% uncertainty. Alpha spectrometry of the electrodeposited sample showed alpha peaks from $^{210}Po, ^{234}U$ and $^{239}Pu$ having energy resolution (FWHM) of 18.3, 21.8 and 36.0 keV respectively. The electrodeposition and alpha spectrometry for a natural uranium sample of domestic origin gave $^{238}U : ^{234}U = 1 : 6.1{\times}10^{-5}$ and for a neutron-irradiated uranium sample did $^{238}U : ^{239}Pu : ^{241}Am = 100 : 0.0263 : 5.20{times}10^{-5}$. The result of $^{238}U$ determination in the irradiated sample by electrodeposition-alpha spectrometry was in accord within ${\pm}1.6%$ of relative error with the results of solid fluorimetry and mass spectrometry. For $^{239}Pu$ the result of electrodeposition-alpha spectrometry was in accord within ${\pm}$4.0% of relative error with the results of anion exchange separation and the thenoyltrifluoroacetone(TTA) extraction both followed by alpha spectrometries.

• Journal of Korean Society of Environmental Engineers
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• v.27 no.2
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• pp.177-183
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• 2005

The effluent quality is directly affected by the separation of biological solids in a final clarifier because the majority of discharged $BOD_5$ and SS are virtually dependent on the results of biological solids in the sedimentation tank effluent. If a final clarifier is effectively designed and operated, the desired goal of clarification for wastewater can be achieved together with the cost reduction in the treatment of wastewater. To this end flow characteristics and the removal efficiency of SS are numerically investigated especially by the change of the inlet position and the installation of baffle to improve the performance of a rectangular final clarifier. The 2-D computer program developed in a rectangular coordinates has been successfully validated against experimental residence time distribution(RTD) curves obtained by tracing radio-isotope. The lowering of the inlet position weakens the density current and induces the settling of SS in the front zone of a clarifier. Thus the decreased traveling distance of the sludge increases the removal efficiency of SS in the effluent. The inlet baffle installed in the front region of clarifier prevents the short circuiting flow and induces to flow into the dense underflow, which eventually improves the effluent quality. In the case of lower inlet position, however, installation of baffle results in degradation of effluent quality. Consequently it is strongly recommended that in-depth numerical study be performed in advance for optimizing a clarifier design and retrofitting to improve effluent quality in a final clarifier.