• 방사성폐기물학회지
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• 제21권2호
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• pp.183-191
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• 2023

The potential impact of hypothetical accidents that occur during the immediate and deferred dismantling of the Kori Unit 1 steam generator has been comprehensively evaluated. The evaluation includes determining the inventory of radionuclides in the Steam Generator based on surface contamination measurements, assuming a rate of release for each accident scenario, and applying external and internal exposure dose coefficients to assess the effects of radionuclides on human health. The evaluation also includes calculating the atmospheric dispersion factor using the PAVAN code and analyzing three years of meteorological data from Kori NPP to determine the degree of diffusion of radionuclides in the atmosphere. Overall, the effective dose for residents living in the Exclusion Area Boundary (EAB) of Kori NPP is predicted, an it is found that the maximum level of the dose is 0.034% compared to the annual dose limit of 1 mSv for the general public. This implies that the potential impact of hypothetical accidents on human health discussed above is within acceptable limits.

• 분석과학
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• 제36권4호
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• pp.191-197
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• 2023

Radioactivity concentrations for natural radionuclides were determined from fine dust samples collected in Jeju, Korea according to atmospheric events (Asian dust, haze, fog-mist, and non-event), and radium equivalent activity was calculated. The mean atmospheric radioactivity concentrations for ²³⁸U, ²³²Th, and ⁴⁰K in 127 fine dust samples were 0.49, 0.24, and 7.23 µBq m^-3, respectively, and the radium equivalent activity was 33.25 Bq kg^-1. The mean concentrations of ²³⁸U and ²³²Th in the fine dust during the Asian dust period were 1.31 and 1.60 µBq m^-3, respectively, above the global average, while the values for the other three atmospheric events were lower. The ratio of ²³²Th/²³⁸U radioactivity during the Asian dust period was 1.22, higher than the ratio for the other three atmospheric events.

• 방사선산업학회지
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• 제18권2호
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• pp.101-107
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• 2024

Rapid screening for internal contamination by alpha- and beta-emitting radionuclides is essential in situations involving radiation workers or radiation accidents. This study focused on the use of urine samples and liquid scintillation counting to quickly and accurately assess contamination. Calibration of the alpha and beta detection areas ensured precise measurement results. The major radionuclides recommended for surveillance during accidents were also considered. This study evaluated the effectiveness of the method by examining various parameters, including the limit of detection, linearity, sensitivity, selectivity, accuracy, ruggedness, and blind test sample analysis. The liquid scintillation counting method is an effective tool for screening urinary samples to detect alpha- and beta-emitting radionuclides, particularly during radiation emergencies, despite some limitations in precision.

• 자원환경지질
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• 제29권2호
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• pp.215-225
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• 1996

All the radionuclides in high-level nuclear waste will decay to harmless levels eventually but for some radionuclides decay is so slow that their radiation remains dangerous for times on the order of tens or hundreds of thousands of years. At the present time, the most favorite disposal plan for high-level radioactive waste is a mined geological disposal in which canister enclosing stable solid form of radioactive waste is placed in mined cavities locating hundred meters below the surface. The chief hazard in such disposal is dissolution of radionuclides from the waste in the groundwater that will eventually carry the dissolved radionuclides to surface environments. The hazard from possible escape of the radionuclides through groundwater can be delayed by engineered and geologic barriers. The engineered barriers can become useless by unexpected geologic catastrophe such as volcanism, earthquake, and tectonic movement and by fraudulent work such as careless construction, improperly welded canisters within the first few decades or centuries. As a result, dangerously radioactive waste which is still intensively radioactive is directly exposed to attack by moving groundwater. All the more, it is almost impossible to control repositories for times more than 10,000 years. Therefore, naturally controlled geologic, barriers whose properties will not be changed within 10,000 years are important to guarantee the safety of repositories of high-level radioactive waste. In Sweden and France, the suitability of granite for the mined geological disposal of high-level waste has been studied intensively. According to the research in Sweden and France, granites has the following physio-chemical characteristics which can delay the transportation of radionuclide by groundwater. First, the permeabilities of granites decreases as the depth increases and is $10^{-8}{\sim}10^{-12}m/s$ at depth below 300 m. Second, groundwater at depth below 300 m has pH=7-9 and reducing condition (Eh=-0.1~0.4). This geochemical condition is desirable to prevent both canister and solid waste from corrosion. Third most radionuclides are not transported by low solubilities and some radionuclide with high solubility such as Cs and Sr are retarded by absorption of geologic media through which ground water flows. Therefore, if high-level waste is disposed at depth below 300 m in the granite body which has a low permeability and is geologically stable more than 10,000 years, the safety of repositories from the hazard due to radionuclide escape can guaranteed for more than 10,000 years.

• 암석학회지
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• 제17권3호
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• pp.179-190
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• 2008

부산 금정구일대의 암석, 토양 및 토양가스 내 주요 환경방사성 핵종들($^{40}K$, $^{228}Ac$, $^{226}Ra$, $^{222}Rn$) 및 U의 분포 특성에 대하여 연구하였다. 연구지역의 화강암질 암석들에서 환경방사성 핵종들의 방사능은 $^{40}K$>토륨붕괴계열>우라늄붕괴계열 순으로 낮게 나타나 화강암질 암석에서 U에 비해 Th이 상대적으로 많이 부화됨을 잘 나타내고 있다. 그러나 암석 내 U 농도 및 $^{226}Ra$ and $^{228}Ac$ 방사능은 암석의 분화단계를 잘 반영하지 못하고 있다. 잔류토양 내 환경방사성 이 핵종들의 방사능과 U의 농도는 모암에 비해 높게 나타나며. 토양가스, 토양 및 암석에서 환경방사성 핵종들의 분포는 낮은 정의 상관관계를 보인다. 이러한 사실들은, 토양가스 및 토양에서 환경방사성 핵종들의 방사능은 모암에 의한 영향보다, 암석의 풍화작용과 토양형성작용 동안 이들 핵종들과 모핵종들의 용탈 및 흡착 등의 거동 특성에 의한 영향을 더 크게 받음을 시사한다.

• 지질공학
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• 제27권4호
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• pp.501-511
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• 2017

이 연구에서는 전라남도 지역의 지하수 170개 소를 대상으로 자연방사성물질인 우라늄, 라돈을 분석하였으며, 지질별로 구분하여 이들의 함량특성을 지구화학적, 통계적으로 고찰하였다. 또한 우라늄과 라돈의 함량을 지질도에 표기하여 이들의 함량분포도를 작성하였다. 우라늄과 라돈의 함량범위는 넓지만 일부 시료를 제외하면 낮은 값을 보인다. 요인분석 결과에 의하면 전남지역의 지하수에서 우라늄과 라돈간의 상관계수는 낮아서, 이 두 성분은 서로 다른 거동특성을 가지는 것으로 판단된다. 서로 거의 무관한 거동특성을 보여주는 이러한 결과는 국내 대부분의 지하수중 우라늄, 라돈 연구결과와도 일치한다. 이들을 제외하면 주요 수질항목들 간에는 높은 상관계수가 나타나는데, 이들은 일반적인 물-암석반응의 결과임을 지시한다.

• Journal of Radiation Protection and Research
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• 제13권2호
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• pp.78-87
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• 1988

원전 사고시 (또는 원자력 발전소 사고시) 환경영향 평가에 중요하게 고려해야 될 핵종을 도출 제시하기 위해 WASH-1400에서 중요하게 고려하고 있는 25원소 54핵종의 노심재고량을 ORIGEN2 코드로써 계산한 후 환경으로 동일비율로 방출된다고 가정하여 급성피폭시 초기효과에 중요한 장기인 소화관, 골수, 갑상선, 허파에 대해 각 핵종에 의한 피폭선량을 평가함으로써 각각의 핵종이 초기효과에 미치는 상대적 중요도를 산출하였다. 그 결과 각 장기에 대한 초기효과에 상대적으로 중요하게 나타난 원소들은 소화관에 대해서는 Np, Ce, Ru, Y, Zr의 순으로, 골수에 대해서는 Np, I, La, Sr, Ba의 순으로, 갑상선에 대해서는 I, Te으로 요오드외원소들의 상대적중요도는 극히 미미하였고, 허파에 대해서는 Cm, Ce, Ru, Pu, Zr순으로 나타났다. 따라서 기존의 환경영향 평가시 갑상선과 전신 피폭선량에 고려되고 있는 요오드 원소와 불활성기체 외에도 원전사고 후 충분한 양이 방출될 때 인근 주민의 장기에 대한 초기효과에 크게 영향을 미치는 핵종이 많으며 이들 핵종들은 선원항 평가시 또는 사고시의 환경영향 평가시에 비중을 두고 고려해야 할 것이다.

• Journal of Radiation Protection and Research
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• 제45권2호
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• pp.88-94
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• 2020

Background: The International Commission on Radiological Protection (ICRP) has recently published report series on the occupational intakes of radionuclides (OIR) for internal dosimetry of radiation workers. In this study, the optimized monitoring program including the monitoring interval and the minimum detectable activity (MDA) of major radionuclides was suggested to perform the routine individual monitoring of internal exposure based on the ICRP OIR. Materials and Methods: The derived recording levels and the critical monitoring quantities were reviewed from international standards or guidelines by the International Atomic Energy Agency (IAEA), the International Organization for Standardization (ISO), and the European Radiation Dosimetry Group (EURADOS). The OIR data viewer provided by ICRP was used to evaluate the monitoring intervals and the MDA, which are derived from the reference bioassay functions and the dose coefficients. Results and Discussion: The optimal monitoring intervals were determined taking account of two requirement conditions on the potential intake underestimation and the MDA values. The MDA requirement values of the selected radionuclides were calculated based on the committed effective dose from 0.1 mSv to 5 mSv. The optimized routine individual monitoring program was suggested including the optimal monitoring intervals and the MDA requirements. The optimal MDA values were evaluated based on the committed effective dose of 0.1 mSv. However, the MDA can be adjusted considering the practical operation of the routine individual monitoring program in the nuclear facilities. Conclusion: The monitoring intervals and the MDA as crucial factors for the routine monitoring were described to suggest the optimized routine individual monitoring program of the occupational intakes. Further study on the alpha/beta-emitting radionuclides as well as short lived gamma-emitting nuclides will be necessary in the future.

• 한국방사성폐기물학회:학술대회논문집
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• 한국방사성폐기물학회 2005년도 춘계 학술대회
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• pp.485-495
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• 2005

본 연구에서는 자연토양에 대한 방사성 핵종(Co, Sr)의 단일 성분의 흡착 및 탈착 거동 특성과 Carboxymethyl-${\beta}$-cyclodextrin(CMCD)를 이용한 탈착저항성에 대한 연구를 수행하였다. 방사성핵종의 흡착 거동을 살펴보기 위하여 흡착속도 실험과 등온 흡착 실험을 수행 하였으며, 흡착 실험 결과를 기존의 흡착 모델식에 적용하여 보았다. 탈착 실험은 일정한 pH와 이온강도 조건에서 CMCD를 주입하였을 때와 주입하지 않았을 때의 탈착경향을 비교분석 하였다. 흡착 실험 결과 자연토양에 대해 스트론튬(Sr)이 코발트(Co) 보다 흡착이 잘 되었고, 코발트, 스트론튬 모두 흡착 속도는 pseudo-second order model을, 그리고 등온 흡착결과는 Sips model을 따르는 것으로 나타났다. 방사성 핵종의 탈착은 비가역적인 형태의 탈착거동을 보였으며, CMCD의 주입량 증가함에 따라 탈착도 증가하는 결과를 나타냈다.

• Nuclear Engineering and Technology
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• 제39권6호
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• pp.747-752
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• 2007

The Proton Engineering Frontier Project (PEFP) has designed and developed a proton linear accelerator facility operating at 100 MeV - 20 mA. The radiological effects of such a nuclear facility on the environment are important in terms of radiation safety. This study estimated the production rates of radionuclides in the soil around the accelerator facility using MCNPX. The groundwater migration of the radioisotopes was also calculated using the Concentration Model. Several spallation reactions have occurred due to leaked neutrons, leading to the release of various radionuclides into the soil. The total activity of the induced radionuclides is approximately $2.98{\times}10^{-4}Bq/cm^3$ at the point of saturation. $^{45}Ca$ had the highest production rate with a specific activity of $1.78{\times}10^{-4}Bq/cm^3$ over the course of one year. $^3H$ and $^{22}Na$ are usually considered the most important radioisotopes at nuclear facilities. However, only a small amount of tritium was produced around this facility, as the energy of most neutrons is below the threshold of the predominant reactions for producing tritium: $^{16}O(n,\;X)^3H$ and $^{28}Si(n,X)^3H$ (approximately 20 MeV). The dose level of drinking water from $^{22}Na$ was $1.48{\times}10^{-5}$ pCi/ml/yr, which was less than the annual intake limit in the regulations.