• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2274-2281
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• 2024

RESRAD-ONSITE v7.2 code is used to assess the radiation effects on a farmer resident located in a hypothetical contaminated site planned for the first nuclear power plant project in Vietnam, namely Ninh Thuan 1, after decommissioning. Derived concentration guideline levels are preliminarily calculated for 17 radionuclides that are assumed to remain on a contaminated surface soil with an initial concentration of 1 pCi/g in the protected area of NPP site. For a reliable estimation, the site-specific conditions regarding the geological, hydrological, climate, and occupancy data gathered from the Feasibility Study Report (FSR) and relevant literatures for the Ninh Thuan 1 NPP site is employed as input parameters. The calculation results indicate that the peak of total exposure dose is estimated to be ca. 0.191 mSv/yr at the time of decommissioning, and then decrease over time. Furthermore, the protected site is assessed to be released at ca. 6.71 years after decommissioning under the regulation on radiation protection in Vietnam. Through this study, a radiation exposure model for residents living near the Ninh Thuan 1 NPP is preliminarily established by using the RESRAD-ONSITE code, which are expected to be useful for future implementation of the Ninh Thuan 1 NPP project in Vietnam.

• Nuclear Engineering and Technology
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• 제16권2호
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• pp.64-69
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• 1984

방사성폐기물 처분과 관련하여 산청, 온양 그리고 무안에서 채취한 국산점토에 대한 Cs-137 및 Sr-90의 흡착특성과 이들 핵종의 점토층이동에 대하여 고찰하였다. 흡착분배계수(Ksorp)를 회분식 흡착실험으로 결정한 결과 Cs-137의 경우 8,000-17,000ml/g 그리고 Sr-90의 경우 10,000-15,000m1/gr 범위의 값이었다. 이때 액상의 초기농도는 0.l$\mu$Ci/ml이었다. 산청과 온양의 점토는 흡착성능이 우수하였으나 무안의 점토는 현저하게 낮았다. 이것은 무안점토에 다량 존재하는 석영성분때문인 것으로 생각되었다. 이상의 흡착특성을 Freundlich형의 형태로 다음과 같이 표시할 수 있었다. $C_{R}$=18.0 $C_{A}$$^{0.74}$ : Cs-137, $C_{R}$=0.84 $C_{A}$$^{0.45}$ : Sr-90. 이 관계식을 BOX모델에 적용하여 점토층내에서의 핵종이동을 모사한 결과 국산점토가 처분장의 충진제로서 효과적임을 확인하였다.하였다.하였다.

• Carbon letters
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• 제22권
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• pp.1-13
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• 2017

Porous materials play a vital role in science and technology. The ability to control their pore structures at the atomic, molecular, and nanometer scales enable interactions with atoms, ions and molecules to occur throughout the bulk of the material, for practical applications. Three-dimensional (3D) porous carbon-based materials (e.g., graphene aerogels/hydrogels, sponges and foams) made of graphene or graphene oxide-based networks have attracted considerable attention because they offer low density, high porosity, large surface area, excellent electrical conductivity and stable mechanical properties. Water pollution and associated environmental issues have become a hot topic in recent years. Rapid industrialization has led to a massive increase in the amount of wastewater that industries discharge into the environment. Water pollution is caused by oil spills, heavy metals, dyes, and organic compounds released by industry, as well as via unpredictable accidents. In addition, water pollution is also caused by radionuclides released by nuclear disasters or leakage. This review presents an overview of the state-of-the-art synthesis methodologies of 3D porous graphene materials and highlights their synthesis for environmental applications. The various synthetic methods used to prepare these 3D materials are discussed, particularly template-free self-assembly methods, and template-directed methods. Some key results are summarized, where 3D graphene materials have been used for the adsorption of dyes, heavy metals, and radioactive materials from polluted environments.

• 한국축산식품학회지
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• 제37권2호
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• pp.297-304
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• 2017

Animal-origin food products pose serious threat to public food safety due to high microbial loads. The microbial and radioactive contaminations in commercial cold duck meat products were evaluated. Ten different lots of commercial samples ($C_1-C_{10}$) were classified based on type and smoking process. All samples were highly contaminated (< 4-7 Log CFU/g) with total aerobic bacteria (TAB), yeasts and molds (Y&M), and 7 samples ($C_1-C_7$) were positive for coliforms. Furthermore, three samples were contaminated with Listeria monocytogenes ($C_4-C_6$) and one with Salmonella typhimurium ($C_6$). No radionuclides ($^{131}I$, $^{137}Cs$, and $^{134}Cs$) were detected in any sample. The results of DEFT (direct epifluorescent filter technique)/APC (aerobic plate count), employed to screen pre-pasteurization treatments of products, indicated that smoked samples were positive showing DEFT/APC ratios higher than 4. Notably, the samples showed a serious threat to microbial safety, thus were irradiated with electron-beam (e-beam). The $D_{10}$ values for S. typhimurium and L. monocytogenes were 0.65 and 0.42 kGy, respectively. E-beam application at 3 and 7 kGy resulted in reduction of initial TAB, Y&M, and coliform populations by 3 and 6 log cycles, respectively. Thus, e-beam was proven to be a good decontamination approach to improve the hygiene of cold duck meat.

• 한국지하수토양환경학회지:지하수토양환경
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• 제22권1호
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• pp.27-32
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• 2017

Cesium (Cs) generated by nuclear accidents is one of the most hazardous radionuclides because of its gamma radiation and long half-life. Especially, when Cs is exposed on the soil environments, Cs is mainly adsorbed on the topsoil and is strongly combined with tiny soil particle including clay minerals. The adsorption of Cs onto soil can vary depending on various physicochemical properties of soil. In this study, the adsorption characteristics between soil and Cs were investigated according to various physicochemical properties of soil including organic matter contents, cation exchange capacity (CEC), soil particle size, and the types of clay minerals. Soil organic matter inhibited the adsorption of Cs onto the soil because organic matter was blocking the soil surface. In addition, it was estimated that the CEC of the soil influenced the adsorption of Cs onto the soil. Moreover, more Cs was adsorbed as the soil particles size decreased. It was estimated that Cs was mostly adsorbed onto the topsoil, this is related to the clay mineral. Therefore, soil organic matter, CEC, soil particle size, and clay minerals are considered the key factors that can influence the adsorption characteristics between soil and Cs.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2004년도 학술논문집
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• pp.158-166
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• 2004

원자력 발전소에서 발생하는 방사성 폐기물인 이온교환수지, 제올라이트, 활성탄 및 슬러지에 포함된 핵종 분석을 위한 최적의 산분해 조건을 확립하였다. 방사성 폐기물의 분해에는 혼합산을 이용한 밀폐형 극초단파 산분해법을 사용하였으며, 제안한 방법에 따른 산분해 후의 용액은 맑고 색이 없는 투명한 상태임을 확인할 수 있었다. 또한, 산분해 과정을 거친 각각의 용액 시료는 ICP-AES와 AAS를 사용하여 분석하였고, 모의 방사성 폐기물에 첨가한 5종의 금속 원소들은 94% 이상의 높은 회수율을 보여주었다. 화학적 특성을 고려하여 제안된 산분해 조건은 핵종 분석을 위한 효과적인 전처리 방법으로써, 향후 원전의 유형별 방사성 폐기물에 대해 보편적으로 적용될 수 있을 것으로 판단된다.

• Journal of Radiation Protection and Research
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• 제28권3호
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• pp.207-213
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• 2003

$^{14}C$은 중수로원전에서 연돌(Stack)을 통해 방출되는 중요한 방사성 핵종중의 하나로, 대략 95% 가량이 이산화탄소의 형태로 발생되고 방출되고 있다. 방사성탄소는 발생에너지가 낮은 베타 방출체로서 외부피폭은 크게 영향을 미치지 않는다. 따라서 중수로에서 탄소는 흡입이나 섭취를 통해 작업자 체내로 유입되는 경우에만 내부피폭을 일으키고 있다. 일반적으로 탄소는 신체에서 불활성 기체와 같은 거동을 보이기 때문에 섭취경로에 의한 피폭이 흡입경로에 의한 피폭보다 훨씬 높은 것으로 알려져 있다. 따라서 작업장에서 탄소의 흡입에 의한 방사선 피폭은 거의 일어나지 않으나 캐나다 원전의 압력관 교체 작업시 아주 소량의 피폭을 일으킨 경험이 있다. 본 논문은 원전 작업장에서 일어날 수 있는 방사성탄소의 흡입에 대비하여 방사선 피폭평가를 위한 방사선방호 프로그램을 수립할 목적으로 방사성탄소의 인체 대사모델 등에 대한 분석을 수행하였다.

• Journal of Radiation Protection and Research
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• 제31권2호
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• pp.69-89
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• 2006

Biological mechanisms for ionizing radiation effects are different at low doses than at high doses. Radiation hormesis involves low-dose-induced protection and high-dose-induced harm. The protective component is associated with a reduction in the incidence of cancer below the spontaneous frequency, brought about by activation of defensive and repair processes. The Linear No-Threshold (LNT) hypothesis advocated by the International Commission on Radiological Protection (ICRP) and the Biological Effects of ionizing Radiation (BEIR) Report VII for cancer risk estimations Ignores hormesis and the presence of a threshold. Cancer incidences significantly less than expected have been found in a large number of epidemiological studies including, airline flight personnel, inhabitants of high radiation backgrounds, shipyard workers, nuclear site workers in scores of locations throughout the world, nuclear power utility workers, plutonium workers, military nuclear test site Participants, Japanese A-bomb survivors, residents contaminated by major nuclear accidents, residents of Taiwan living in $^{60}Co$ contaminated buildings, fluoroscopy and mammography patients, radium dial painters, and those exposed to indoor radon. Significantly increased cancer was not found at doses <200 $mSv^*$. Evidence for radiation hormesis was seen in both sexes for acute or chronic exposures, low or high LET radiations, external whole- or partial body exposures, and for internal radionuclides. The ubiquitous nature of the Healthy Worker Effect (HWE)-like responses in cellular, animal and epidemiological studies negates the HWE as an explanation for radiation hormesis. The LNT hypothesis is wrong and does not represent the true nature of the dose-response relationship, since low doses or dose-rates commonly result in thresholds and reduce cancer incidences below the spontaneous rate. Radiation protection organizations should seriously consider the cost and health implications of radiation hormesis.

• 대한핵의학회지
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• 제23권1호
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• pp.49-54
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• 1989

Many previously described nuclear medicine procedures to assess glomerular filtration rate (GFR) required numerous blood samples obtained over a period of several hours to determine plasma concentrations of the injected radiopharmaceuticals. And other indirect methods of determining renal clearance have some problems due to individual variations in volume of distribution of the radionuclides used. Rescently reported Jackson's method have the great advantages that is a direct measurement method requiring less than 40 min of imaging time and single blood sampling. And it correctly accounts for individual variations in volume of distribution of the radiopharmaceuticals and can be done with routine renal scintrgraphy. We measured $^{99m}Tc-DTPA$ renal clearance with Jackson's method during the routine $^{99m}Tc-DTPA$ renal scintigraphy in 63 patients admitted to department of internal medicine in SNUH. In 23 cases among 63 patients creatinine clearence was accounted simultaneously. The range of $Cl_{DPDA}$ was from 19.9 ml/min to 170 ml/min and the correlation of $Cl_{DPDA}$ and creatinine clearance was discribed by Y=16.2570+0.7852 X($X=Cl_{DTPA}$ Y=creatinine clearance). And the correlation coefficient r was 0.88. We concluded that $^{99m}Tc-DTPA$ renal clearance measurement with Jackson's method was clinically useful to account GFR that can be done with routine $^{99m}Tc-DTPA$ renal scintigraphy simultaneously.

• 대한방사선기술학회지:방사선기술과학
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• 제31권1호
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• pp.41-47
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• 2008

한국 성인 남성 표준인(Korean Reference Adult Male)의 기초 자료를 이용하여 수학적 모의 피폭체(Mathematical Phantom)를 제작하였다. 또한 이를 이용하여 방사성옥소($^{131}I$)의 각 장기별 S-value를 산출 하였다. 산출된 S-value는 기존 ICRP-23표준인에 근거하여 산출한 MIRD 5, 및 ORNL-TM 8381자료와 비교해 보았다. 그 결과 S-value는 한국 성인 남성 표준인에 기초한 모의 피폭체가 높은 값을 나타냈다. 이는 몸통이라는 특수한 공간에 위치하게 되는 선원장기(source organ) 및 표적장기(target organ)가 함유하고 있는 구성물질도 중요하지만 그에 못지않게 이들이 차지하고 있는 위치 및 방사성핵종의 특성 또한 중요하게 작용한다는 것을 알 수 있었다.