• Journal of Radiation Protection and Research
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• v.33 no.3
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• pp.105-112
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• 2008

To measure the soil-to-plant transfer factors ($TF_a,\;m^2\;kg^{-1}$-fresh) of radionuclides deposited during the growing season of potato, a radioactive solution containing $^{54}Mn,\;^{60}Co,\;^{85}Sr$ and $^{137}Cs$ was applied to the soil surfaces in soil boxes 2 d before seeding and three different times during the plant growth. For the pre-seeding application (PSA), radionuclides were mixed with the topsoil (loamy sand and 5.2 in pH). The plant parts investigated were leaves, stems, tuber skin and tuber flesh. The $TF_a$ values of $^{54}Mn,\;^{60}Co,\;^{85}Sr$ and $^{137}Cs$ from the PSA were in the ranges of $1.9{\times}10^{-4}{\sim}1.5{\times}10^{-2}$, $1.8{\times}10^{-4}{\sim}7.5{\times}10^{-4}$, $4.0{\times}10^{-4}{\sim}1.6{\times}10^{-2}$, $1.5{\times}10^{-4}{\sim}3.9{\times}10^{-4}$ respectively, for different plant parts. The TFa values from the growing-time applications were on the whole a few times lower than those from the PSA. For $^{54}Mn,\;^{85}Sr$ and $^{137}Cs$, the $TF_a$ values from the early- or middle-growth-stage application were higher than those from the late-growth-stage application, whereas the opposite was true for $^{60}Co$. Leaves and tuber flesh had the highest and lowest $TF_a$ values, respectively, in most cases. The total uptake from soil by the four plant parts was in the range of $0.05{\sim}3.16%$. In the third year following the PSA, the $TF_a$ values of $^{54}Mn,\;^{60}Co$ and $^{137}Cs$ were $11{\sim}25%$, $21{\sim}25%$ and $38{\sim}67%$ of those in the first year, respectively, depending on the plant parts. The present results can be used for estimating the radiological impact of an acute radioactive deposition during the growing season of potato and for testing the validity of relevant food-chain models.

• Journal of the Korean Society of Radiology
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• v.5 no.1
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• pp.5-10
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• 2011

Based on basic concept of detection limit, sample measurement time & background measurement time was considered, and MDA values according to background measurement time and sample measurement time in land samples(river soil, surface soil, drinking water, underground water, surface water, pine leaf, mugwort) analysis among environmental samples were compared. Seeing the water sample analysis result, it was shown that most of the samples were not detected, and most of the samples in land specimen analysis showed to be below the detection limit of "Ministry of Education, Science and Technology Announcement Je-2008-28-ho", but $^{137}Cs$ which is one of artificial radioactive nuclide was detected in some samples. It can be traced back to 1950s and 1960s when nuclear tests were carried out in atmosphere and catastrophic Chernobyl atomic power station accident that caused fallouts in the sky, and this is common level of detection that can be observed worldwide. Seeing the result that the $^{134}Cs$(which is a isotope of $^{137}Cs$, and it has relatively short half life) was not detected in all samples, it can be considered it doesn't affect to the operation of atomic power station.

• Journal of Radiation Protection and Research
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• v.10 no.2
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• pp.113-121
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• 1985

For the safety assessment of radwaste treatment and disposal, the leaching characteristics of $Cs^+\;and\;Sr^{++}$ from the cement-solidified radwastes was investigated by means of the survey and analysis of the activity leach rate and cumulative leach fraction of $^{137}Cs\;and\;^{90}Sr$ leaching from solidified radwastes. The cylindrical cement-solidified samples were made by the sodium silicate method and neutralization method changing the mole density of simulated liquid radwaste, type of cement, adding material and concentration of boric acid. The leaching study was carried out by the method using simulated PWR concentrated liquid radwaste solidified in cement that had been processed following the recommendations of IAEA. All the experimental results are in well accordance with the research data reported previously, but the watertight cement-solidified radwastes show rather high leach rate of radioactivity. It is learned, therefore, that the watertight cement is not adequate as the material for the solidified radwastes.

• Nuclear Engineering and Technology
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• v.22 no.1
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• pp.20-28
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• 1990

In this study the migration experiment using packed column with crushed tuff was conducted as a basic research to develop migration model of radionuclides through geologic media. The main emphasis was put on evaluating the validity of migration models. For this, two models were introduced: one is the model which is based on the assumption of instantaneous equilibrium reaction and the other the model based on kinetic process such as intraparticle diffusion. The coefficient of hydrodynamic dispersion in packed column was determined using iodine as nonsorbing tracer. The hydrodynamic dispersion coefficient, D$_{L}$ was shown to be 0.11$\times$10$^{-2}$ $\textrm{cm}^2$/min under the condition of the column porosity of 0.483 and the average water velocity of 0.915$\times$10$^{-2}$ cm/min. The distribution coefficient, Kd of Cs-137 on crushed tuff was 11.3 cc/g at the concentration of 2$\times$10$^{-6}$ M and the temperature of 2$0^{\circ}C$. The breakthrough curve of Cs-137 through packed column was shown to have an asymmetric curve in which long trailing tail appears at the end part of the curve. The results obtained from the comparison of introduced models with experimental data indicated that the mass transfer model with intraparticle diffusion as rate-controlling step simulated the behaviors of Cs-137 migration more adequately, when compared with the bulk reaction model in which the assumption of instantaneous equilibrium reaction was maded. Consequently, the intraparticle diffusion was found to be an important factor in the migration of Cs-137 through packed column.n.

• The Korean Journal of Nuclear Medicine
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• v.7 no.1
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• pp.51-54
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• 1973

The use of ion-exchange resins for the treatment of radioactive wastes has many advantages, but thes eare rather expensive as compared with the Korean vermiculite. The Korean vermiculite has slightly different chemical constituents from the ones produced in other countries, and its physical properties might be applicable to the management of radioactive waste, in a small nuclear installation. The decontaminating effect of Korean vermiculite for the low-level radioactive liquid was investigated. $^{106}Ru,\;^{90}Sr,\;and\;^{137}Cs$ were utilized for the experiments. The removal rates by Korean vermiculite were calculated for $^{106}Ru,\;^{90}Sr\;and\;^{137}Cs$ and the removal rates increased as the weight of vermiculite in the exchange column increased. The decontaminating constants, $K_d$ of the Korean vermiculite for $^{106}Ru,\;^{90}Sr\;and\;^{137}Cs$ were 2.7, 69.3 and 263ml/g respectively. Through the results of experiments, the application of Korean vermiculite column to the treatment of low-level radioactive waste is quite feasible.

• Proceedings of the Korean Society of Soil and Groundwater Environment Conference
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• 2003.04a
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• pp.337-339
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• 2003

The technology removing radionuclides from soil using soil washing was studied. The main radionuclides contaminated in the soil are Cs$^{137}$ and Co$^{60}$ . It is suitable that scrubbing time is 4 hours and a mixing ratio of soil weight and washing solution volume is 1:10. more than two times continuous scrubbing method with 0.5 M oxalic acid was needed to remove Cs$^{137}$ and Co$^{60}$ from soil more than 70%. Radionuclides removal efficiencies of recycling washing solutions recycled with strong acid resins until 5 times are similar to that of 0.5 M oxalic acid.

• Proceedings of the Korean Nuclear Society Conference
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• 1995.05a
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• pp.911-918
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• 1995

동적섭식경로모델을 사용하여 "목초$\longrightarrow$우유$\longrightarrow$사람"의 핵종이동 경로에 대해 침적시점에 따른 입력변수의 민감도와 결과에 대한 불확실성분석을 수행하였다. Cs-137과 Sr-90의 경우 모든 침적시점에 대해 재부유인자가 가장 높은 중요도를 보였다. 두 핵종에 대해 침적시점에 따른 입력변수의 중요도의 변화는 비슷한 유형을 보였다. 목초의 성장기에서 전이율이 상대적으로 중요도가 높았고, Cs-137의 전이율은 Sr-90의 경우보다 높은 중요도를 나타냈다. 목초의 비성장기에서 Sr-90에 대한 농축인자의 중요도는 매우 높았다. Cs-137과 Sr-90에 의한 피폭선량의 95% 신뢰도구간은 약 1 $\times$ $10^1$, 5 $\times$ $10^1$ 범위를 나타냈다. 범위를 나타냈다.

• Journal of Radiation Protection and Research
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• v.30 no.4
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• pp.167-174
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• 2005

The concentrations of natural and artificial radionuclides in soil and gamma ray dose rate in air at 233 locations in Korea have been determined. The national mean concentrations of $^{232}Th,\;^{226}Ra,\;^{40}K,\;^{137}Cs\;and\;^{90}Sr$ in soil were $60{\pm}31,\;33{\pm}14,\;673{\pm}238,\;35{\pm}9.3\;and\;5.0{\pm}3.4\;Bq\;kg^{-1}$, respectively. The mean gamma-ray dose rate at 1 m above the ground was $7918\;nGy\;h^{-1}$. $^{137}Cs$ concentration had highly significant correlation with organic matter content and cation exchange capacity. $^{90}Sr$ concentration had slightly coherent with pH. The results have been compared with other global radioactivity and radiation measurements.

• Proceedings of the Korean Vacuum Society Conference
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• 1996.06a
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• pp.137-137
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• 1996

• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.409-414
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• 1998

5 년간의 기술실증 및 안전성 검토를 거쳐 한국원자력연구소내 실증소각시설을 자체발생 가연성 $\beta$/${\gamma}$폐기물을 소각하는 시설로 인허가를 얻었다. 동위원소포함 모의폐기물 및 원전발생 가연성폐기물 실증소각 결과에 기준을 두고 연간 배출오염원 및 가상 사고시의 방사학적 위해성을 평가하여 저준위 폐기물을 부지내에서 소각처리할 때 그 위해성은 무시할 수 있을 것으로 미미함 을 확인하였다. 실증시험으로 주된 배출 방사선원은 고온의 소각로에서 휘발성이 크고 저준위 폐기물내 농도가 큰 반휘발성 Cs-137 및 Cs-134로, 발전소 가연성폐기물과 같은 핵종조성을 가진 0.109 mCi/kg 의 소각시 Cs-137 및 Cs-134의 배출농도가 공기중허용농도의 10%를 약간 상회하는 것으로 평가되었다. 비방사성 CsCI을 이용한 시험소각을 통하여 사용되는 저온배기체처리계통 에서의 휘발된 Cs의 배기체 냉각시 입자화 및 제거특성을 고찰한 결과 휘발된 기체상 Cs성분은 건식배기체 냉각공정을 거치면서 대부분 마이크론 크기이하의 입자로 생성되지만 5% 미만이 전이영역 크기에 분포하여 주여과장치인 여과포집진기에서 제거효율이 99.9% 이상이었다.