• Proceedings of the Korean Nuclear Society Conference
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• 1995.05b
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• pp.845-852
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• 1995

방사성폐기물의 처분시에는 원자력발전소와 유사한 안전개념들 도입하여 다중방벽을 구성하는 것이 일반적이다. 다중방벽중에서 뒷채움재는 처분안전성 망상의 주도적 역할을 하는 요소로서 지하수 침투방지, 방사성핵종 이동저지능의 기능을 가져야 한다 석탄회를 뒷채움재의 부재료로서 사용하기 위해서는 방사성폐기물처분장 설계에 적용할 때 안전성과 경제성을 만족시킬 수 있어야 한다. 본 인구에서는 석탄회의 핵종에 대한 흡착능의 관점에서 석탄회의 이용가능성들 평가하였다. 또한 Column 실험을 통하여 표면확산과 공극확산을 비교, 분석함으로써 석탄회를 통과하는 방사성핵종의 이동기구를 검토하였다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.10 no.4
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• pp.295-303
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• 2012

Based on the data observed and analyzed on a groundwater flow system in the KURT (KAERI Underground Research Tunnel) site, the transport of radionuclides, which were assumed to be released at the supposed position, was calculated on the time-domain. A groundwater pathway from the release position to the surface was identified by simulating the groundwater flow model with the hydrogeological characteristics measured from the field tests in the KURT site. The elapsed time when the radionuclides moved through the pathway is evaluated using TDRW (Time Domain Random Walk) method for simulating the transport on the time-domain. Some retention mechanisms, such as radioactive decay, equilibrium sorption, and matrix diffusion, as well as the advection-dispersion were selected as the factors to influence on the elapsed time. From the simulation results, the effects of the sorption and matrix diffusion, determined by the properties of the radionuclides and underground media, on the transport of the radionuclides were analyzed and a decay chain of the radionuclides was also examined. The radionuclide ratio of the mass discharge into the surface environment to the mass released from the supposed repository did not exceed $10^{-3}$, and it decreased when the matrix diffusion were considered. The method used in this study could be used in preparing the data on radionuclide transport for a safety assessment of a geological disposal facility because the method could evaluate the travel time of the radionuclides considering the transport retention mechanism.

• Journal of Radiation Protection and Research
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• v.17 no.2
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• pp.49-59
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• 1992

A new model was developed in order to investigate the effects of chelating agents on the migration of a radionuclide in the form of ion or chelate. The migration behavior of the chelated radionuclide was analyzed by formulating a convective-dispersion transport equation which included a degradation of chelating agent and chelated radionuclide. The mathematical model was analytically solved and checked with the existing retardation factor. The results show that the migration velocity of the chelated radionuclide was much faster than the ionic one due to the decreased retardation. Therefore, it was concluded that a new remedial action should be developed to reduce the generation and release of chelating agents from the nuclear power plant into the environment.

• Proceedings of the Korean Nuclear Society Conference
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• 1997.10a
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• pp.375-380
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• 1997

모의 방사성 세탁폐액을 제조하여 오존에 의한 세제 파괴를 확인하고 활성탄 및 이온교환수지를 이용하여 세제 및 Co, Cs 제거율을 조사하였으며 모의 방사성 세탁폐액을 오존으로 부분적으로 산화ㆍ파괴시킨후 활성탄 및 이온교환수지에 의한 흡착 및 이온교환 실험을 수행하여 오존의 세제 파괴가 방사성 물질 제거에 미치는 영향을 조사하였다. 오존에 의해 세제는 75% 정도 제거될 수 있었고 활성탄으로 방사성 모의세탁폐액을 처리할 때 세제농도가 증가하면 방사성 핵종 제거율이 감소하였다. 이온교환수지로 세제를 제거할 때 성취가능 제거율은 Co의 경우 99% 이상이었으며, 세제 존재시 방사성 Co 및 Cs 제거율은 감소하며, 방사성 모의세탁폐액을 오존으로 조사후 활성탄과 이온교환수지로 방사성 핵종을 제거할 때 그 제거율은 거의 변화가 없었다. 이상과 같은 실험 결과로부터 오존으로 부분적으로 산화시켜 활성탄의 세제 제거효율을 최대화하고, 역삼투막에 의한 방사성 핵종을 제거하며 이온교환수지로 잔류 방사성 핵종을 완전히 처리할 수 있는 복합 공정을 도출하였다.

• Tunnel and Underground Space
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• v.13 no.1
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• pp.20-32
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• 2003

To understand the behavior of migration of contaminants in a fractured porous medium is a key to assure the overall safety of a potential radwaste repository. The feasible retention mechanism of contaminant transport in a tinctured medium are sorption of contaminants on solid surface and matrix diffusion of contaminants from a fracture into an adjacent porous medium. The acceleration mechanisms are the migration of contaminants in the form of pseudo-colloids and the limit of a volume f3r matrix diffusion. In this paper, the effects of these two acceleration mechanisms are studied mathematically, then semi-analytically computed by the application of the Talbot theorem and verified. Results indicate that the acceleration processes cannot be neglected in the modeling of contaminant transport in a fractured porous medium.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2003.11a
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• pp.290-299
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• 2003

고준위 방사성 폐기물 처분장으로부터 유출된 핵종이 인간 생태계에 도달하여 어느 정도의 선량률로서 피폭을 일으키는가를 보이기 위한 생태계 피폭 모델링 및 평가 연구는 처분안전성 평가의 최종 단계로서 핵종 유출의 결과가 인간에게 어느 정도의 방사선 피폭을 주는가를 보이는 것이 그 주요한 내용이 된다. 이 연구를 통하여 도출된 시나리오 중에서 가장 기본이 될 수 있는 생태계에 대하여 AMBER를 사용하여 피폭 계산을 수행하여 선량 환산 인자 평가를 계산해 보았다. AMBER 코드는 핵종 이동 계산을 위해 여러 개의 구획을 설정하고 구획간의 핵종 이동은 핵종 전이 계수(mass transfer coefficient)를 이용하여 계산한다.

• Journal of Radiation Protection and Research
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• v.35 no.1
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• pp.12-20
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• 2010

In a primary system at nuclear power plants (NPPs), various radionuclides including fission products and corrosion products are generated due to the complex water conditions. Particularly, $^3H,\;^{14}C,\;^{58}Co,\;^{60}Co,\;^{137}Cs,\;and^{131}I$ are important radionuclides in respect of dose assessment for radiation workers and management of radioactive effluents. In this paper, the dominant contributors of radiation exposure for radiation workers and the member of public adjacent to NPPs were reviewed and the process of dose assessment attributable to those contributors were introduced. Furthermore, the analysis for some examples of radiation exposure to radiation workers and the public during the NPP operation was carried out. This analysis included the notable precedents of internal radiation exposure and contamination of demineralized water occurred in Korean NPPs. Particularly, the potential issue about the dose assessment of tritium and carbon-14 was also reviewed in this paper.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2_spc
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• pp.305-315
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• 2020

For geological disposal of radioactive wastes, a method was proposed to evaluate the radionuclide transport in the biosphere by calculating the elapsed time of nuclide migration. The radionuclides were supposed to be introduced from a natural barrier and reached a large surface water body following a groundwater flow in a shallow subsurface. The biosphere was defined as a shallow subsurface environment that included aquifers on a host rock. Using the proposed method, a calculation algorithm was established, and a computer code that implemented the algorithm was developed. The developed code was verified by comparing the simulation results of the simple cases with the results of the analytical solution and a public program, which has been widely used to evaluate the radiation dose using the radionuclide transport near the surface. A case study was constructed using the previous research for radionuclide transport from the hypothetical geological disposal repository. In the case study, the code calculated the mass discharge rate of radionuclide to a stream in the biosphere. Because the previous research only demonstrated the transport of radionuclides from the hypothetical repository to the host rock, the developed code in the present study could help identify the total transport of radionuclide along the complete pathway.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.635-643
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• 1995

핵의학(nuclear medicine )이 란 방사성 및 안정 핵종의 동위원소표지 화합물을 인체에 투여하여, 관심장기의 형태 및 기능을 평가하여 해부학적 또는 생리학적 상태를 진단, 치료하는 의학의 전문 분야이다. 핵의학에 이용되던 방사성 핵종은 1960년대 까지만 해도 $^{131}$ I이 주였으나 1970년대 부터는 $^{99}$Mo -$^{99m}$ Tc 발생기와 $^{99m}$ TC으로 표지된 방사성의 약품이 활발히 이용되면서 $^{131}$ I을 대신하게 되었다. 원자로-생산핵종들의 특성은 중성자가 과잉이어 붕괴시 배타입자를 방출하는 점으로, 이것이 각종 질병의 치료에 이용되고 있다. 특히 각종 표시 화합물의 성질을 이용하여 원하는 부위에 방사선을 집중시킬 수 있음이 외부조사보다 유리한 점이다. 방사성핵종을 이용한 악성종양의 치료에 가장 성공적인 것은 분화된 갑상선 암환자에서 $^{131}$ I을 사용한 것이며, 갈색세포종 등에 $^{131}$ I-MIBG도 효과적이다. 악성종양의 골전이 치료에 베타선을 방출하는$^{32}$P, $^{186}$ Re, $^{153}$ Sm 등이 이용되었다. 종양의 동맥에 주입하여 세동맥이나 모세혈관에 걸리는 기름, 교진 또는 입자에 의한 치료에 $^{131}$ I-lipiodol, ethiodol, $^{32}$P 또는$^{90}$ Y흡사 ceramic resin 미소구 $^{166}$ Ho 유산중합체 미소구 등이 이용된다. $^{166}$ Ho, $^{198}$ Au, $^{32}$P, $^{90}$ Y, $^{169}$ Er, $^{186}$ Rc, $^{131}$ I, $^{211}$ At 등 의 방사성 핵종의 교질, 미소구 또는 단세포군 항체표지 형태로 직접 종양내 또는 공동이나 체강에 투여하는 치료법이 있다. 류마치스 관절염의 슬관절에 $^{165}$ Dy colloid를 주사하는 $^{166}$ Ho-MAA도 활발히 이용되고 있다.

• Nuclear Engineering and Technology
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• v.27 no.4
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• pp.532-543
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• 1995

In this study, a transport model was developed in order to analyze and predict the transport behaviors of radionuclides mediated by pseudo-colloid in the fractured rock media. The effect of pseudo-colloid formation on the transport of a radionuclide was shown to be tory significant when an ap-parent pseudo-colloid formation constant, $A_{ap}$ (㎥/kg), os greater than 100. It was resulted from example calculations that the transport of Pu-239 was faster than Ni-63 because pseudo-colloid formation constant of Pu-239 was venter than that of Ni-63. Thus, it can be concluded that acceleration of radionuclide migration may be occurred because the pseudo-colloid formation of radionuclides increases the amount of mobile components in the solution and consequently decreases the amount of radionuclides adsorbed on the stationary solid medium.