• Resources Recycling
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• v.6 no.3
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• pp.22-27
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• 1997

Recycling of radioactively contaminated metal wasles is very attractive to reduce thc final disposal volumc of the radioactive wastes, thereby maximizing the usage of nahrral rzsuunts and minimizmg the detrimental effects of thz rzdioaclive wastes on the environment. In the recycling process, many complicated processes arc involved. Among those processes the 'surface contamination removal techniques such as physical, chemical and electrochern~calm ethods are the most critical and Ircquently applied in accordance with the contamination characteristics and the chemical compositions of the metal wastes. In this sludy, the sulfuric acid-cerium method and electmchemical methods were applied lu removc the conatiminated suhce. The results showed the surface contaminalion could he lowered to the background levcl by lhasc mclhods.

• Progress in Medical Physics
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• v.6 no.2
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• pp.71-81
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• 1995

Consecutive brain 〔Tc-99m〕ECD SPECT studies before and after acetazolamide (Diamox) administration have been performed with patients for the evaluation of cerebrovascular hemodynamic reserve. However, the quantitaitve potential of SPECT Diamox imaging is limited as a result of degrading fractors such as finite detector resolution, attenuation, scatter, poor counting statistics, and methods of data analysis. Making physical measurements in phantoms filled with known amounts of radioactivity can help characterize and potentially quantify the sensitivities. However, it is often very difficult to make a realistic phantom simulating patients in clinical situations. By computer simulation, we studied the sensitivities of ECD SPECT before and after Diamox administration. The sensitivity is defined as ($\Delta$N/N)/($\Delta$S/S)$\times$100％, where $\Delta$N denotes the differences in mean counts between post-and pre-Diamox in the measured data, N denotes the mean counts before Diamox in the measure data, $\Delta$S denotes the differences in mean counts between post-and pre-Diamox in the model, and S denotes the mean counts before Diamox in the model. In clinical Diamox studies, the percentage changes of radioactivity could be determined to measure changes in radioactivity concentration by Diamox after subtracting pre-from post-Diamox data. However, the optimal amount of subtraction for 100％ sensitivity is not known since this requires a thorough sensitivity analysis by computer simulation. For consecutive brain SPECT imaging model before and after Diamox, when 30％ increased radioactivity concentrations were assingned for Diamox effect in model, the sensitivities were measured as 51.03, 73.4, 94.00, 130.74％ for 0, 100, 150, 200％ subtraction, respectively. Sensitivity analysis indicated that the partial voluming effects due to finite detector resolution and statistical noise result in a significant underestimation of radioactivity measurements and the amount of underestimation depends on the. ％ increase of radioactivity concentration and ％ subtraction of pre-from post-Diamox data. The 150％ subtraction appears to be optimal in clinical situations where we expect approximately 30％ changes in radioactivity concentration. The computer simulation may be a powerful technique to study sensitivities of ECD SPECT before and after Diamox administration.

• The Microorganisms and Industry
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• v.14 no.2
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• pp.11-12
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• 1988

심층지하에도 미생물은 존재하고 있는가\ulcorner 이러한 의문은 현재 미국에서 진행되고 있는 일련의 연구로 인하여 그 해답에 제시되고 있다. 심층 미생물 탐색 연구의 시작은 1981년에 시작한 Dept of Engergy (DOE)의 심층지하 운반계획(Subsurface Transport ; SST) 계획이었다. 이 계획의 주된 목적은 미량금속, 무기화합물및 방사능원소의 움직임 및 지하지층과 지하수에서의 수문학적 이동을 조절하는 지질화학, 수문학, 생물학적 과정에 대한 기초연구를 하는 것이었다. 여기에서 얻어진 정보는 지하환경에서 물질들이 이동하며 희석도고 있다는 것과 그에 대한 조건들을 제시해 주었다. 당시 많은 국가들이 심층 지하수를 이용하지만, 그에 대한 미생물 분포에 관한 지식은 거의 없었다.

• The Journal of Korean Society for Radiation Therapy
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• v.9 no.1
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• pp.1-7
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• 1997

다량의 방사선에 피폭되는 경우 인체에 해로운 영향을 미치는 것은 틀림이 없으나 미량의 방사선인 경우에는 다량의 방사선인 경우와 다른 효과를 나타내며 심지어 정반대의 영향을 나타내기도 한다고 볼 수 있으며 여러 역학조사에서 이러한 사실이 증명되고 있다. 1991년의 국제방사선방어기구(ICRP) 보고서 및 1994년의 UNSCEAR 보고서는 미량의 방사선에 대한 적응반응을 인정하고 있다. 일부 학자들은 소량의 방사선에 지속적으로 피폭(연간 1 rem)됨으로써 암사망률을 감소시킬 수 있다고 주장하면서 현재의 개념을 수정하여 피폭한계 및 법적 제한 등을 변경하여 환경방사능을 증가시킴으로써 향후 인류의 생활의 질을 향상시켜야 한다고 주장하고 있다.

• Defense and Technology
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• no.7 s.245
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• pp.74-81
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• 1999

열화우라늄은 물질특성상 방사능을 유출하는 독성 물질이고 핵 폐기 물질이기 때문에, 공학적 가공 과정을 거쳤다 하더라도 안정성에 대한 검증과 신뢰성에 많은 의문이 제기되어 왔다. 걸프전 이후 참전 군인과 민간인들에게서 열화우라늄의 폐해로 추정되는 전투후유증과 질병이 발생됨으로써, 그 위해성에 대한 논란이 제기되고 국제적인 이슈로 부상하게 되었다. 따라서, 열화우라늄의 군사적 개발 및 활용 실태와 위해성에 대한 고찰을 통하여, 장차 인류의 쾌적한 환경과 건강유지를 위해 구현되어야 할 방향을 전망하고자 한다.

• 대한방사선방어학회:학술대회논문집
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• 2010.04a
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• pp.180-181
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• 2010

• Proceedings of the Korean Nuclear Society Conference
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• 1997.05b
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• pp.335-340
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• 1997

원전에서 발생하는 방사성 세탁폐액을 환경방사능 Zero Release 개념하에 완전히 처리하는 공정으로서 역삼투막을 이용한 방법이 연구되고 있는데 이에 앞서 역삼투막 공정의 주요 장애요소인 계면활성제 및 현탁물에 의한 탁도 제거를 위한 전처리 공정으로 활성탄과 한외여과막 결합장치를 제작하여 운전하였으며 실험 결과 90% 이상의 높은 세제 제거율과 60% 이상의 탁도 제거율을 얻을 수 있었다.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.3 no.2
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• pp.149-157
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• 2005

PFC(Perfluorocarbon) decontamination process is one of best methods to remove hot particulate adhered at inside surface of hot cell and surface of equipment in hot cell. It was necessary to develop a particulate filtration equipment to reuse PFC solution used on PFC decontamination due to its high cost and to minimize the volume of second wastewater. Contamination characteristics of hot particulate were investigated and then a filtration process was presented to remove hot particulate in PFC solution generated through PFC decontamination process. The removal efficiency of PVDF(Poly vinylidene fluoride), PP(Polypropylene), Ceramic(Al$_{2}$O$_{3}$ filter showed more than 95$\%$. The removal efficiency of PVDF filter was a little lower than those of other kiters at same pressure(3psi). A ceramic filter showed a higher removal efficiency with other filters, while a little lower flux rate than other filters. Due to inorganic composition, a ceramic filter was highly stable against radio nuclides in comparison with PVDF and PP membrane, which generate H$_{2}$ gas in e-radioactivity atmosphere. Therefore, the adoption of ceramic filter is estimated to be suitable for the real nitration process.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.18 no.2
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• pp.157-167
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• 2020

Removing radioactive concrete is crucial in the decommissioning of nuclear power plants. However, this process generates radioactive aerosols, exposing workers to radiation. Although large amounts of radioactive concrete are generated during decommissioning, studies on the internal exposure of workers to radioactive aerosols generated from the cutting of radioactive concrete are very limited. In this study, therefore, we calculate the internal radiation doses of workers exposed to radioactive aerosols during activities such as drilling and cutting of radioactive concrete, using previous research data. The electrical-mobility-equivalent diameter measured in a previous study was converted to aerodynamic diameter using the Newton-Raphson method. Furthermore, the specific activity of each nuclide in radioactive concrete 10 years after nuclear power plants are shut down was calculated using the ORIGEN code. Eventually, we calculated the committed effective dose for each nuclide using the IMBA software. The maximum effective dose of ¹⁵²Eu constituted 83.09% of the total dose; moreover, the five highest-ranked elements (¹⁵²Eu, ¹⁵⁴Eu, ⁶⁰Co, ²³⁹Pu, ⁵⁵Fe) constituted 99.63%. Therefore, we postulate that these major elements could be measured first for rapid radiation exposure management of workers involved in decommissioning of nuclear power plants, even if all radioactive elements in concrete are not considered.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2005.06a
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• pp.161-166
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• 2005

In KAERI, about 3,100 drums containing soil have been stored. The soils were generated from the decommissioning process of Seoul office in 1988. Those soils occupy about $27\%$ of the capacity of the radioactive waste storage facility and make it difficult to maintain the storage facility. The major radioactive nuclides contained in the soils were expected to be Co-60 and Cs-137. As 16 years have passed, the radioactivity of those nuclides have decayed a lot. In this study, as a basis of regulatory clearance, radionuclides and radioactivity concentration of soils were analyzed. As a result, there are only Co-60 and Cs-137 in soils as ${\gamma}-emitters$. The total concentration of ${\gamma}-emitters$ in soil is analyzed as about $0.01\;{\sim}\;0.12$ Bq/g. As the soils are expected to be regulatory cleared in 2009, those concentrations will decay to be less than 0.1 Bq/g. This concentration can be meet the regulatory criteria suggested by IAEA. The regulatory clearance will be proceeded based on not only the assessment results of environmental influence but also related regulations.