• Proceedings of the Korean Nuclear Society Conference
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• 1998.05b
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• pp.509-514
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• 1998

ORIGEN-S 전산코드로 계산된 가압경수로(PWR)사용후핵연료 내에 존재하는 방사성핵종비 $^{134}$ Cs/$^{137}$Cs 및 $^{154}$ Eu/$^{137}$Cs 를 감마선 분광실험으로 측정한 값과 비교하여 핵연료의 연소도를 결정하였다. 고리 1호기 및 2호기 사용후핵연료봉에 대한 감마선 분광실험을 한국원자력연구소 조사재시험시설(IMEF)과 조사후시험시설(PIEF)의 시험기기 및 장치를 이용하여 수행하고 이 결과로부터 $^{134}$ Cs/$^{137}$Cs 와 $^{154}$ Eu/$^{137}$Cs 의 핵종비를 측정하였다. 이와 별도로 사용후핵연료의 연소도, 냉각시간, 초기농축도등에 따른 $^{134}$ Cs/$^{137}$Cs 와 $^{154}$ Eu/$^{137}$Cs의 핵종비를 ORIGEN-S 코드로 계산을 하였으며, 이 핵종비와 연소도 사이의 관계를 회귀분석하여 2차 다항식 함수로 유도하였다 이관계식과 감마선 분광실험으로 측정한 $^{134}$ Cs/$^{137}$Cs와 $^{154}$ Eu/$^{137}$Cs 의 핵종비를 이용하여 각각의 연소도를 결정할 수 있었다.

• Journal of Radiation Protection and Research
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• v.23 no.2
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• pp.115-121
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• 1998

Adsorption characteristics of the radionuclides and stable elements on AMP and $MnO_2$ in the seawater have been investigated. The adsorption yield of AMP was 97.5% for $^{137}Cs$, 11.8% for $^{85}Sr$, and 15.1% for $^{131}I$, while being less than 6% for other radionuclides and elements. The AMP showed the highest adsorption yield for $^{137}Cs$. The adsorption yields of $MnO_2$ were more than 90% for all radionuclides and elements, except for $^{40}K$, $^{137}Cs$ and $^{203}Hg$ of which the adsorption yields were less than 8%.

• Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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• v.5 no.1
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• pp.9-17
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• 2007

In order to compare the correlation of radioactivity ratio between the radwaste streams and the primary coolant of PWR NPPs, A RCS sampling kit was installed to primary coolant system for the collection of the radionuclides during the normal operation of NPPs. RCS samples were collected from PWR type of domestic NPPs through 2004 to 2005, and pretreated with acid microwave digestion or leaching method to assay quantitatively of several interesting radionuclides. The radioactivity ratios of $^{137}Cs\;to\;^{60}Co$ in a filter cartridge and a resin cartridge were 2.3E-2 and 7.3E-1, respectively. At a same period of the reactor operating cycle, the radioactivity ratios of $^{137}Cs\;to\;^{60}Co$ were 6.3E-1 for a evaporator bottom, 6.7E-1 for a spent resin, and 5.6E-2 for a dry active waste, so that these radwaste streams were identified as having similar characteristics with the corresponding RCS samples.

• Nuclear Engineering and Technology
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• v.27 no.1
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• pp.25-32
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• 1995

Batch sorption experiments were conducted to investigate the sorption characteristics of $^{137}$ Cs, known for the primary target of safety assessment in low-level radwaste disposal, onto domestic rocks such as Granite and Tuff. A response surface analysis method was applied to quantify the effect of 3 independent variables (［Cs］, ［Vol/Wt］, ［pH］) on the sorption. Ac a result, initial Cs concentration appeared to be the most important variable within the range of the study. A significant effect of ［Vol/Wt］ on Kd was observed. The sorption of Cs was pH-insignificant. The sorption extent of nuclides onto tuff was more significant than that onto granite. The pH-insignificant sorption behavior of Cs was discussed in terms of the surface electrical properties and the solution chemistry. The sorption tendency of nuclides onto geomedia studied was interpreted by adopting the water structure modification theory.

• Korean Journal of Environmental Agriculture
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• v.16 no.4
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• pp.304-310
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• 1997

In greenhouse, a mixed solution of Mn-54, Co-60, Sr-85 and Cs-137 was applied to the soil of culture boxes 2 days before sowing cucumber and at 4 different times during its growth for measuring their transfer factors (TFs) for fruit and migration in soil. TFs varied with radionuclide, application time and harvest time by factor of up to about 60. Variations in TFs with application time showed different patterns among radionuclides. TFs decreased on the whole in the order of Sr-85 > Mn-54 > Co-60 > Cs-137. TFs of Mn-54, Co-60 and Cs-137 mixed with topsoil before sowing were a little higher than those for the soil-surface application made at an early growth stage while no difference in Sr-85 TF was found. After harvest, soil concentrations of the radionuclides applied at an early growth stage were examined. They decreased with increasing soil depth and 80${\sim}$99% of the radioactivity remained in the top 3cm. Soil pemeation of the radionuclides migration decreased in the order of Sr-85 > Mn-54 > Co-60 > Cs-137. The present data can be utilized in estimating radionuclide concentration in cucumber fruit, taking proper measures for its harvest and consumption and designing the best way of soil decontamination following an radioactive deposition during the cucummber growing season.

• Journal of the Korean Society for Marine Environment & Energy
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• v.4 no.1
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• pp.3-13
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• 2001

Dissolved /sup 137/Cs, /sup 239.240/Pu, /sup 238/Pu and /sup 90/Sr contents in winter and spring of the Yellow Sea were determined to describe the distribution of artificial radionuclides. Surface water samples (100 liter) were collected by using a submerged pump, and subsurface samples (>10m depth) were collected using a 10L Niskin water sampler mounted to the Rosette sampler. The levels in the surface water ranged between 1.78～3.38 mBq kg/sup -1/ for /sup 137/Cs, 2.17～13.35 μBq kg/sup -1/ for /sup 239,240/Pu, and 1.97～3.96 mBq kg/sup -1/ for /sup 90/Sr, respectively. In particular, the concentration of /sup 239.240/Pu were 1/10 of those in the vicinity of Changjiang estuary (61～83 μBq kg/sup -1/). The difference of /sup 238.240/Pu concentration between surface and bottom water was <3.0 μBq kg/sup -1/in the Yellow Sea. It suggests that in the Yellow Sea which has shallow and high suspended sediments, /sup 239.240/Pu is preferentially removed from the water columm. The water column inventory of /sup 239.240/Pu in the Yellow Sea constitute about 0.7～0.9 % of the estimated fallout input to the area. The activity ratios of /sup 239.240/Pu//sup 137/Cs and /sup 137/Cs//sup 90/Sr ranged between 0.001～0.005, 0.79～1.65, respectively, and similar to those of open ocean which global fallout is the only source of artificial radionuclides. Therefore, it suggests that most of these artificial radionuclides in the Yellow Sea may be controlled by the atmospheric input.

• Proceedings of the Korean Radioactive Waste Society Conference
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• 2004.06a
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• pp.131-132
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• 2004

원자력연구소에 보관 중인 오염 토양폐기물을 토양 세척법으로 제염하여 비 방사성폐기물화 한다면 그 부피를 10% 이하로 저감시킬 수 있으며 연구소의 고체 방사성폐기물 저장 용량을 크게 늘릴 수 있다. 1988년 발견 당시 오염 토양 폐기물의 주요 방사성 핵종은 Co-60 이었는데 시간경과에 따라 Cs-134, 137 이 주요 방사성 핵종이 되었다. 오염토양 폐기물의 60 % 이상은 방사능 농도가 극히 낮아 물리적으로 입도를 분리하거나 수 세척에 의해 비 방사성폐기물화 할 수 있음을 파악하였다.(중략)

• Journal of Radiation Protection and Research
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• v.21 no.1
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• pp.51-58
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• 1996

Underground migration of $^{54}Mn,\;^{60}Co,\;^{85}Sr\;and\;^{137}Cs$ in paddy and upland conditions was studied through two years' greenhouse experiment. At early and late growth stages of rice, soybean, Chinese cabbage and radish, a mixed solution of the radionuclides was applied to the water or soil surfaces of the culture boxes filled with an acidic loamy-sandy soil for the upper 20cm. Soil was sampled in layers upto $15{\sim}20cm$ down after harvest. Soil concentrations of the radionuclides decreased exponentially with increasing soil depth and more than 80% of the radioactivities remained in top $3{\sim}4cm$. The mobility of the radionuclides decreased in the order of $^{85}Sr>^{54}Mn>^{60}Co{\geq}^{137}Cs$. Downward migrations of the radionuclides were the greatest in rice soil and the lowest in soybean soil which was fertilized with the least amount of N, P and K. Differences in depth profiles between two application times indicate that the amount of daily migration from $0{\sim}1cm$ layer to the lower area decreases with increasing time after deposition. By a simultaneous addition of KCl and lime following the earlier application, downward migration in soybean, Chinese cabbage and radish soils changed little or retarded more or less but that in rice soil accelerated a little.

• Journal of the Mineralogical Society of Korea
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• v.7 no.2
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• pp.91-96
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• 1994

중.저준위 방사성 폐기물의 대표적인 핵종인 137Cs, 90Sr에 대한 캐올리나이트의 흡착특성을 수용액의 이온강도와 pH의 영양하에서 알아보았다. 흡착실험은 회분식으로 하였고, 사용한 수용액은 NaCl, CaCl2, MgSO4, KCL 각각을 10-1, 10-2, 10-3, 10-4 mole/$\ell$로 하였다. 수용액광물 평형상태의 pH를 4.5, 7.0, 10.5로 조절하였다. 실험결과 캐올리나이트의 Cs, Sr 흡착은 이온강도와 pH에 상당한 영향을 받으며, Sr 흡차에 양이온들의 경쟁은 Ca2+ Mg2+>K+>Na+ 순을 보이고, Cs의 경우에는 K+>Ca2+ Mg2+>Na+의 순을 보인다. 이는 수용액상에서 이온들의 수호에너지와 관련되며, 광물입자와 이온들의 물구조변환특성에 의해 설명된다. Cs과 Sr 사이에 흡착우선성은 산성 내지 약알카리에서는 Cs이 Sr보다 흡착이 잘 되나, 강알칼리성 환경에서는 Sr이 Cs보다 흡착이 잘 되는 pH 의존성을 보였다. 수용액의 pH가 증가함에 따라 핵종의 흡착량이 증가하는데, 이는 캐올리나이트의 흡착자리인 실라놀과 알루미놀에 의한 제타전위가 pH에 의존함과 잘 일치한다.

• Resources Recycling
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• v.31 no.5
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• pp.20-25
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• 2022

In this study, the applicability of microalgae was evaluated for eco-friendly decontamination of cesium-137 (Cs-137) and strontium-90 (Sr-90), which are radioactive nuclides contained in radioactive waste. The monolithic radioactive solution used in the experiment was manufactured at a concentration of 1.5 Bq/mL Cs-137 and 1.0 Bq/mL Sr-90 by diluting a standard radioactive solution and distilled water. This experiment used two types of microalgae, Chlorella Vulgaris was used for Sr-90 decontamination and Hematococcus pluvialis for Cs-137 decontamination. The experimental method is to put the microalgae cultured for 2 weeks into a bottle with a semi-permeable membrane, and then put the bottle in which the microalgae was put into the manufactured radioactive solution, so that the microalgae and the radioactive solution react through the semi-permeable membrane for 48 hours. For the radioactivity concentration analysis of each sample, a gamma-ray nuclide analyzer was used for Cs-137, a γ-ray isotope, and a Liquid Scintillation Count(LSC) was used f or Sr-90, a β-ray isotope. As a result of the experiment, it was confirmed that about 88.0 % of Cs-137 and about 89.7 % of Sr-90 could be decontaminated, and about 98.6 % of Sr-90 was finally able to be decontaminated by the two-stage decontamination method.