• Journal of Korean Society of Environmental Engineers
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• v.22 no.5
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• pp.827-835
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• 2000

Adsorption characteristics of uranium on activated carbon whose surface is modified with $HNO_3$ and/or NaOH were investigated. Na-OAC, which was the activated carbon treated with both $HNO_3$ and NaOH. showed higher adsorption capacity than OAC, which was treated with $HNO_3$, as well as Na-AC, which was treated with only NaOH. This can be explained based on the surface functional groups increased by surface modification of activated carbon and the change of solution pH as adsorption proceeds. From these experimental results, it is thought that the pH of uranium solution and surface functional groups on the activated carbon surface are the governing factors in the uranium adsorption system.

• Nuclear industry
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• v.7 no.8 s.54
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• pp.56-61
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• 1987

원자력발전소에서 생성되는 폐기물들의 양을 줄이는 것은 주요한 관심사이다. 방사성폐기물의 감용은 여러 방법으로 성취될 수 있는데, 본고에서는 액체폐기물 처리계통의 증발기를 효율적으로 운전하여 폐기물의 양을 감소시키는데 초점을 맞추었다. 이를 위해, 온도와 pH를 변화시키면서 농도가 다른 붕산수들의 침전상태가 조사되었는데, 배관의 보온을 고려하지 않았을 때는 붕산농도 $17wt.\%$까지, 고려했을 때는 $25wt.\%$까지 농축할 수 있음이 밝혀졌다. 또한, 붕산농도의 증가에 따른 시멘트고화체의 압축강도변화를 조사하였고 증발기 농축운전으로 얻어질 경제적 이들을 평가하였다.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.455-462
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• 2003

According to Korean nuclear code requires Periodic Safety Review(PSR) every 10 years should be perform for operating reactor, and selects the eleven PSR safety factors. Among them the review objective of the environmental impact is to determine whether the operator has an adequate programme for surveillance of the environmental impact of the nuclear power plant based on current safety standards. In this paper, the environmental impact in PSR of Wolsong Unit 1 was reflected current safety standards as of the evaluation date. As a result, all items generally satisfied the standards, and the staff also verified that the population dose due to the operation of Wolsong Unit 1 was controlled safely as of the evaluation date.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.17 no.1
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• pp.59-73
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• 2019

A decontamination technology for radioactive liquid wastes was newly developed and hypothetically applied to the liquid waste management system (LWMS) of the nuclear power plant (NPP) to evaluate its decontamination efficacy for the purpose of the fundamental reduction of spent resins. The basic principle of the developed technology is to convert major radionuclide ions in the liquid wastes into inorganic crystal minerals via chemical or biological techniques. In a laboratory batch experiment, the biological method selectively removed more than 80% of cesium within 24 hours, and the chemical method removed more than 95% of cesium. Other major nuclides (Co, Ni, Fe, Cr, Mn, Eu), which are commonly present in nuclear radioactive liquid wastes, were effectively scavenged by more than 99%. We have designed a module including the new technology that could be hypothetically installed between the reverse osmosis (R/O) package and the organic ion-exchange resin in the LWMS of the APR1400 reactor. From a technical evaluation for the virtual installation, we found that more than 90% of major radionuclides in the radioactive liquid wastes were selectively removed, resulting in a large volume reduction of spent resins. This means that if the new technology is commercialized in the future, it could possibly provide drastic cost reduction and significant extension of the life of resins in the management of spent resins, consequently leading to delay the saturation time of the Wolsong repository.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.284-289
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• 2005

According to the nuclear safety regulation policy including the administration of radionuclides in low level radwastes, the evaporator bottoms were mixed with cement to form a stable solidification for identifying the recovery possibility of the C-14. The chemical oxidation method was applied for the extraction of C-14 from the cement waste form. The emitting beta ray of the C-14 extracted from the radwastes was measured with the liquid scintillation counter and calculated by using the quenching correction curves. Only the beta emitting radioactive nuclides of the C-14 in the radwastes was showed the radioactivities with the range of $2.7E+00\;{\sim}\;3.07E+02$ Bq/g.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.16 no.3
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• pp.347-357
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• 2018

The applicability of room temperature ionic liquids (RTILs), 1-alkyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([$C_nmim$] [$Tf_2N$]), was investigated for the extraction of Am(III) and Eu(III) from nitric acid using n-octyl(phenyl)-N,N-diisobutyl carbamoylmethyl phosphine oxide (CMPO) and tri-n-butylphosphate (TBP) as extractants. The distribution ratios of Am(III) and Eu(III) in CMPO-TBP/[$C_nmim$][$Tf_2N$] were measured as a function of various parameters such as the concentrations of nitric acid, CMPO, and TBP. The results were compared with those obtained in CMPO-TBP/n-dodecane (n-DD). With comparable concentrations of the extractants, the distribution ratios obtained with RTILs were much higher than those obtained with n-DD. It was observed that the extraction efficiency was less for Eu(III) than for Am(III). The extraction of Am(III) and Eu(III) decreased with increases in the feed acidity for all three RTILs. The results suggest that the extraction of Am(III) and Eu(III) by CMPO in RTILs from nitric acid proceeds through the cation-exchange mechanism. The distribution ratios of Am(III) and Eu(III) increased with increases in the concentration of CMPO for all three RTILs. A linear regression analysis of the extraction data resulted in a straight line with a slope of about 3, suggesting the involvement of 3 molecules of CMPO during the extraction process.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.650-654
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• 2003

A major problem of nuclear energy is the production of radioactive wastes. Needs for more environmentally favorable method to decontaminate radioactive contaminants make the use of liqui $d^ercritical $CO_2$ as a solvent medium. In removing radioactive metallic contaminants under $CO_2$ solvent, two methods - use of chelating ligands and that of water in $CO_2$ emulsion-are possible. In the chelating ligand method, a combination of ligands that can make synergistic effects seems important. We discuss about the properties of microemulsion formed by F-AOT and that by non-ionic surfactant. By adding acid in water core, decontamination of metallic parts, soils were possible. The rate of metal surface dissolution to the microemulsion solution was measured by QCM. The possibility of recovering the surfactants after use is also mentioned.ed.

• Proceedings of the Korean Nuclear Society Conference
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• 1999.05a
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• pp.321-321
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• 1999

• Nuclear industry
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• v.18 no.7 s.185
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• pp.49-54
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• 1998

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.333-333
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• 2004

고온의 용융염 매질에서 전해 정련 또는 전해제련에 의해 원하는 물질을 회수하기 위한 공정에 있어서 정확한 산화/환원 전위 측정 및 안정된 전위를 인가하기 위해서는 재현성과 내구성이 확보된 기준 전극이 필요하다. 용융염 매질에서 많이 사용되는 기준 전극은 Ag/AgCl 전극으로서 온도 사이클에 대한 전위의 히스테리시스가 작고 고온에서도 전위가 안정하다. Ag/AgCl 기준전극으로 pyrex 봉 하단부를 수 마이크론 두께의 pyrex 박막으로 제작된 것은 고온 용융염에 접촉시 열 충격, 전극류와 충돌에 의한 물리적 취약성 및 고온의 용융염에 의한 부식과 같은 단점이 있다.(중략)