• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
• /
• v.2 no.3
• /
• pp.181-188
• /
• 2004

The contaminative influence of beef due to the inhalation of air and the ingestion of soil of livestock, both of which are dealt with as minor contaminative pathways in most radioecological models but may not be neglected, was comprehensively investigated with the improvement of the Korean food chain model DYNACON. As the results, it was found that both pathways can not be neglected at all in the contamination of beef in the case of an accidental release during the non-grazing period of livestock. The ingestion of soil was more influential in the contamination of beef than the inhalation of air over most time following an release. If precipitation is encountered during an accidental release, contaminative influence due to the ingestion of soil was far greater compared with the cases of no precipitation. This fact was more distinct for a long-lived radionuclide $^{l37}Cs$ than a short-lived radionuclide $^{131}I$ (elemental iodine). Compared with the results for milk performed prior to this study, the contaminative pathways due to the inhalation of air and the ingestion of soil were more important in beef because of longer biological half-lives. On the other hand, in the case of an accidental release during the grazing period of livestock, radioactive contamination due to the ingestion of pasture was dominant irrespective of the existence of precipitation during an accidental release. It means that contaminative influence due to the inhalation of air and the ingestion of soil is negligible, like the cases of milk.

• Proceedings of the Korea Air Pollution Research Association Conference
• /
• 2001.11a
• /
• pp.237-238
• /
• 2001

라돈(Rn-222)은 우라늄(U-238) 방사능계열의 원소로서 라듐(Ra-226)의 알파($\alpha$)붕괴시 자연생성되는 가스상 물질이다. 암석 내에서 생성되어 공극내에서 물에 용해된 라돈은 붕괴하지 않고 상태를 유지하게 되는데 이런 라돈이 존재하는 암석층으로부터 지하수를 취수할 경우, 상당량의 라돈이 지하수속에 용해되어 있을 수 있다. 이렇게 용해된 상당량의 라돈은 실내공기로 휘발하면서 주변으로 확산하게 된다. (중략)

• Tunnel and Underground Space
• /
• v.17 no.1 s.66
• /
• pp.17-25
• /
• 2007

Research and development for disposal of contaminants including radioactive wastes in deep underground have been carried out from laboratory works. However, validation and reliability of the data from the laboratory are arguing issues because they are not obtained from real disposal situations. Underground research laboratory (URL) is not only a solution to overcome such limitations, but also a valuable facility for performance assessment as an engineering scale. However, it requires much budget, and environmental issues can give rise to social conflicts easily. Such considering points related to URL are discussed as well as current status of worldwide URLs are introduced. Furthermore study plans for solute transport in a small-scale underground research tunnel (KURT), which was authorized recently as an non-radioactive facility in Korea, also described.

• Journal of Radiation Protection and Research
• /
• v.32 no.1
• /
• pp.1-8
• /
• 2007

A model for radiological dose assessment in an urban environment, METRO-K has been developed. Characteristics of the model are as follows ; 1) mathematical structures are simple (i.e. simplified input parameters) and easy to understand due to get the results by analytical methods using experimental and empirical data, 2) complex urban environment can easily be made up using only 5 types of basic surfaces, 3) various remediation measures can be applied to different surfaces by evaluating the exposure doses contributing from each contamination surface. Exposure doses contributing from each contamination surface at a particular location of a receptor were evaluated using the data library of kerma values as a function of gamma energy and contamination surface. A kerma data library was prepared fur 7 representative types of Korean urban buildings by extending those data given for 4 representative types of European urban buildings. Initial input data are daily radionuclide concentration in air and precipitation, and fraction of chemical type. Final outputs are absorbed dose rate in air contributing from the basic surfaces as a function of time following a radionuclide deposition, and exposure dose rate contributing from various surfaces constituting the urban environment at a particular location of a receptor. As the result of a contaminative scenario for an apartment built-up area, exposure dose rates show a distinct difference for surrounding environment as well as locations of a receptor.

• Applied Chemistry for Engineering
• /
• v.29 no.2
• /
• pp.127-137
• /
• 2018

Radioactive contamination has become an important environmental concern after the accident occurred in Fukushima Daiichi Nuclear Power Plants. $^{134}Cs$ and $^{137}Cs$ are the major fission products and they are main problems in radioactive contamination. Huge amounts of Cs were released during the Fukushima Daiichi Nuclear Power Plants accident and as a result of this incident, many researchers focused on the development of adsorbents for decontamination of radiotoxic cesium. This review will critically evaluate recent advances in the preparation of Prussian blue and its analogue compounds, which are promising materials for cesium removal. Furthermore, this review will discuss recent studies on the cesium adsorption using different types of clay and clay based adsorbents and summarize various types of newly developed Cs adsorbents reported in recent years.

• Proceedings of the KIPE Conference
• /
• 2018.07a
• /
• pp.183-185
• /
• 2018

최근 석유나 석탄 에너지 사용으로 인한 대기오염 및 미세먼지와 원자력 발전으로 인한 핵 폐기 물질 처리의 어려움, 방사능 오염이 발생하는 문제가 심각해짐에 따라 신재생에너지의 중요성이 대두되고 있다. 이로 인해 정부에서도 신재생에너지의 비중을 확대하기 위한 정책들이 시행되고 있는데 그 중 태양광 발전 시스템이 가장 크게 주목받고 있다. 태양광 발전이 성장함에 따라 다양한 연구가 진행되어왔으며 이 중 DC-DC 컨버터로 구성된 태양광 발전 energy storage system (ESS) 시스템이 효율이 높고 시장성이 좋아 많은 연구가 진행되고 있다. 따라서 본 논문에서는 5kW 태양광 발전 배터리 충전 시스템을 구성하여 컨버터의 동작 및 특성에 대하여 분석하고 이를 시뮬레이션을 통해 내용을 검증하였다.

• Journal of the Korean Society of Radiology
• /
• v.14 no.7
• /
• pp.857-862
• /
• 2020

In March 2011, a tsunami off Japan caused radioactive material that had seeped into the sea from the Fukushima nuclear accident to flow to the Pacific Ocean, causing pollution to sea life. For a comparative evaluation with the area surrounding the site of a nuclear power plant by the release of radioactive materials, an area 20 to 30 km away from the emergency protection plan area was selected as a comparative point considering weather conditions, population distribution, etc. In addition, the government intends to analyze the minimum detection radiation received by residents around the nuclear power plant and evaluate the effective dose. Analysis of tritium radiation from water samples showed that most of the samples were not detected and that 0.0014 % to 0.777 % of the annual legal standard of 1 mSv for the general public had little effect on the human body. Therefore, the measurement and analysis of water samples around the nuclear power plant site is expected to help relieve anxiety, such as exposure to the general public and neighboring residents due to radiation release.

• Journal of radiological science and technology
• /
• v.40 no.4
• /
• pp.633-638
• /
• 2017

The amount of radioactive waste has been rapidly increased with development of radiation treatment in medical field. Recently, it has been a common practice to use I-131 for thyroid cancer, F-18 for PET/CT and Tc-99m for diagnosis of nuclear medicine. All the wastes concerned have been disposed of by means of the self-disposal method, for example incineration, after storage enough to decay less than clearance level. IAEA proposed criteria for clearance level of waste which depends on the individual ($10{\mu}Sv/y$) and collective dose (1 man-Sv/y), and concentration of each nuclide (IAEA Safety Series No 111-P-1.1, 1992 and IAEA RS-G-1.7, 2004). In this study, specific radioactivity of radioactive waste contaminated with Re-186 was measured to confirm whether it meets the clearance level. Re-186 has long half life of 3.8 days relatively and emits beta and gamma radiation, therefore it can be applied in treatment and imaging purposes. The specific radioactivity of contaminated gloves weared by radiation workers was measured by MCA(Multi-channel Analyzer) which was calibrated by reference materials in accordance with the measuring procedure. As a result, comparison evaluation of decay storage period between the half-life which was calculated by attenuation curve based on real measurement and physical half-life was considered, and it is showed that the physical half-life is longer than induced half-life. Therefore, the storage period of radioactive waste for self-disposal may be curtailed in case of application of induced half-life. The result of this study will be proposed as ISO standard.

• Korean Journal of Environmental Agriculture
• /
• v.18 no.3
• /
• pp.215-220
• /
• 1999

Behaviour of a fungicide $^{14}C-propiconazole$ was investigated in a rice plant grown-lysimeter soil. The lysimeter was composed of soil cores of silty clay. $Propiconazole(Tilt\;250^R\;EC)$ plus $^{14}C-labeled$ propiconazole was applied on the surface of lysimeter soil at a rate of 0.12kg/10a after rice transplanting. The application was done consecutively for two years. The behaviours of propiconazole in the lysimeter soil were investigated by measuring the amounts of $^{14}C-leachate$, $^{14}CO_2$, the residues distributed in each soil segment and taken up by rice plants. The relative amounts of $^{14}C$ leached from the lysimeter were the background level of the applied $^{14}C$ throughout expeiment. The amounts of $^{14}CO_2$ evolved from the lysimeter were 5.7 and 7.8% of the original $^{14}C$ in the 1st and 2nd treatment, respectively. The amounts of volatile substances soil were the background level throughout experiment, which indicated that propiconazole was stable chemically in the experimental condition. The $^{14}C-activities$ absorbed and translocated into rice plants were 3.7 and 7.6% in 1st and 2nd treatment, respectively. The $^{14}C-activities$ in the soil layer of the lysimeter was distributed mainly in the depth of 0 to 20cm, which suggested propiconazole did not have the risk of groundwater contamination.

• Proceedings of the Korean Institute of Surface Engineering Conference
• /
• 2017.05a
• /
• pp.136-136
• /
• 2017

화학제염 기술은 산화제, 환원제, 금속이온, 무기산등이 혼합되어 있는 화학용액을 사용하여 원전기기 계통 내부에 생성된 고방사능 준위의 산화막과 오염물질을 제거하는 기술이다. 원전의 해체 및 유지보수에 있어 방사능 피복저감을 위한 필수적인 기술이다. 현재 원전 해체 산업은 잠재성이 높은 고부가가치 창출 산업으로 주목을 받고 있다. 원전 보유국의 경우, 기존 상용 제염기술과는 차별성 있는 제염기술을 확보하고자 노력하고 있다. 기존의 공정과 비교하여 공정비용 및 시간을 감소시킬 수 있어야 할 뿐만 아니라, 화학용액에 의한 원전 계통 금속 부품의 부식 및 손상을 최소화해야 한다. 금속 부품이 화학약품에 의한 부식손상을 받는다면 금속 부품의 수명 및 재활용 가치가 감소하기 때문에, 화학제염 기술 적용에 있어 용액에 대한 재료의 건전성 평가가 사전에 필히 이루어져야 한다. 본 연구에서는 원전 냉각재 펌프용 재료로 주로 사용되는 Stainless 304강을 시험편으로 선정하여, 화학제염 시험공정 3가지에 대한 부식손상 특성을 규명하였다. 산화공정은 과망간산($HMnO_4$) 용액을 공통으로 사용하였으며, 산화공정 종료 후 환원공정은 각 시험공정에 따라 시험공정 1은 옥살산($H_2C_2O_4$) 2000ppm, 시험공정 2는 옥살산($H_2C_2O_4$)1500ppm + 시트르산($H_8C_6O_7$)500ppm, 그리고 시험공정 3은 옥살산($H_2C_2O_4$) 3000ppm 용액을 각각 투입하여 수행하였다. 산화, 환원공정을 1Cycle로 하여, 각 시험공정 별로 총 5Cycle을 실시하였다. 각 시험공정 Cycle종료 후 시험편을 취외하여 무게감량측정, SEM(Scanning electron microscope) 분석, 3D현미경분석 그리고 타펠분극 실험을 실시하였다. 각 분석결과를 토대로 하여, Stainless 304강에 대한 화학제염 시 모델별 시험공정에 따른 부식특성을 규명하였다.