• 분석과학
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• 제19권1호
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• pp.18-30
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• 2006

This paper describes the cumulative deposition of fallout Pu in soil and lichen at the present time and give the characteristics of fallout Pu deposits in the soil. In the soil of the forest, the accumulated depositions of $^{239,240}Pu$ were estimated to be in the range of 34.0 to $101.2Bq\;m^{-2}$ with an average value of $65.3{\pm}21.6Bq\;m^{-2}$. The average inventory of $^{239,240}Pu$ in the forest was calculated to be two times higher than that in the hill. Also, the deposited activities of $^{239,240}Pu$ in cultivated soil were significantly lower than those in the hill or forest. However, the cumulative depositions of fallout Pu in the volcanic ash soil on Cheju Island were much higher than those in the forest and hill soils. The measured activity concentrations of Pu isotopes in lichens and mosses showed large variations, due to characteristics of species and life span of lichen and moss colonies. From depth profiles, it was found that most of the fallout Pu has been accumulated in upper 10 cm layer of soil. Except for a few cases, the concentrations of $^{239,240}Pu$ in soil tended to decrease exponentially with increasing soil depth. Among parameters affecting the cumulative deposition of fallout Pu, organic substances and rainfall play an important role in the retention and relative mobility of fallout Pu in the soil. However, pH showed a weak correlation with the deposition of fallout Pu in the soil. From sequential leaching experiments, Pu was found to be associated predominantly with the "organic" and "oxy-hydroxy" fractions. Both the activity ratios of $^{238}Pu/^{239,240}Pu$ and $^{241}Pu/^{239,240}Pu$ in soils, lichens and mosses and the atomic ratios of $^{240}Pu/^{239}Pu$ in soils are close to those observed in the cumulative deposit global fallout from nuclear weapon testings. The results obtained from this research make it possible to interpret and predict the behavior of fallout Pu under natural conditions.

• 한국철도학회논문집
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• 제12권5호
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• pp.811-818
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• 2009

본 연구에서는 시공중인 터널의 변상에 대한 원인을 규명하고 접근이 불가능한 일부 변상부에 대한 경험적 규모산정기법을 제시하였다. 부피팽창계수(bulking factor)를 이용한 변상부 규모예측 결과는 토모그래피용 시추공내 시추자료를 이용한 결과와 비교 분석하였으며 제시한 경험적 기법의 정확도를 확인하였다. 한편 변상부의 진행성 파괴 여부를 예측하기 위하여 미소파괴음(acoustic emission) 기법을 도입하여 계측을 수행하였으며 이 결과, 추가적인 진행성 파괴는 없는 것으로 파악되었다. 향후에는 미소파괴음 기법을 이용한 터널의 건전도 평가 등의 연구가 수행될 예정이다.

• Journal of Radiation Protection and Research
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• 제27권1호
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• pp.11-19
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• 2002

1998년부터 1999년까지 대전지역 대기부유진, 강수 및 낙진 중 $^7Be$ and $^{137}Cs$ 방사능 농도의 계절적 변화를 검토하였다. 대기부유진, 강수 및 낙진중 $^7Be$의 연평균 농도범위는 각각 $3.80{\sim}4.29 mBq\;m^{-3},\;1.25{\sim}1.67 Bq\;l^{-1},\;19.7{\sim}22.3 MBq\;km^{-2}$였다. 한편 대기부유진, 강수 및 낙진 중 $^{137}Cs$ 연평균 농도범위는 $1.08{\sim}1.28{\mu}Bq\;m^{-3},\;0.44{\sim}2.66\;mBq\;l^{-1}$ 및 $0.036{\sim}0.0455\;MBq\;km^{-2}$ 범위였다. 대기부유진 및 낙진 중 $^7Be$ and $^{137}Cs$ 농도는 낙진량이 많은 봄과 가을철에 높은 농도를 나타내었으며, 강수 중 $^7Be$ and $^{137}Cs$ 농도는 타 계절에 비해 강수량이 많은 여름철에 비교적 낮은 농도를 나타내었다. 한편 낙진과 강수에 의한 $^7Be$ and $^{137}Cs$의 연평균 총 침적량은 각각 $80.7{\sim}137 MBq\;km^{-2}$ 및 $0.059{\sim}0.060MBq\;km^{-2}$ 범위였으며, $^7Be$의 총 침적량중 약 80% 이상이 강우에 의해 침적되는 반면, $^{137}Cs$은 약 60% 정도가 낙진에 의해 침적되는 것을 알 수 있었다.

• Journal of Nutrition and Health
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• 제11권1호
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• pp.21-26
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• 1978

The hazards to man of nuclear fallout produced by the nuclear tests in the atmosphere were briefly discussed. Seriousness of hazards due to Sr-90 existing not only in the nuclear fallout but also in the spent nuclear fuel and nuclear waste was pointed out. The uncertainty in health hazards to Koreans coming from the relatively low fraction of Ca intake from dairy products was stressed. In order to minimize the possible additional damage due to the particular Korean meal pattern, the investigation of ways to reduce the Sr-90 intake from Korean foods was proposed.

• Ocean Science Journal
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• 제41권4호
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• pp.261-290
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• 2006

The concentrations of man made radionuclides in surface seawater since early '60s are here reported as measured in Italy and Japan. Most of the data refers to $^{90}Sr$ and $^{137}Cs$, but occasionally the concentrations of $^{89}Sr$ and $^{134}Cs$ in some Italian samples are also given. The main sources of man made radionuclides were the global fallout produced by the nuclear weapon tests and the Chernobyl accident. The respective contributions to the contamination of surface seawater around both countries are discussed.

• 한국환경보건학회지
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• 제29권3호
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• pp.21-27
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• 2003

The purpose of this study was to investigate the distribution and characteristics of heavy metals in the fallout dust deposits at the middle and high schools. We collected the samples at 60 schools in Kongju, Incheon and Daejeon on from September to November, 2001, and analyzed Cadmium(Cd), Copper(Cu), Lead(Pb) and Zinc(Zn) from them. Zn was the highest level as 551 $\pm$ 79.9 ppm, and the next order were Pb, Cu, and Cd as 146.0 $\pm$ 15.2 ppm, 98.7 $\pm$ 14.4 ppm and 5.21 $\pm$ 0.76 ppm, respectively. The rates of schools exceeding the soil environmental standards were 56.3% in Cd, 53.3% in Zn, 51.5% in Pb, and 31.7% in Cu, respectively. Cd and Pb were the highest levels at schools in Daejeon as 6.30 $\pm$ 0.87 ppm and 171 $\pm$ 26.1 ppm, respectively. Cu and Zn were the highest levels at schools in Incheon as 176.2 $\pm$ 55.8 ppm and 919.8 $\pm$ 185.7 ppm, respectively. At Incheon, Cu and Zn levels were significantly higher than Kongju(p=0.04l), and Daejeon(p=0.016), respectively. Total pollution index(PI) of heavy metals was 1.51 $\pm$ 0.16. PI was 2.00 $\pm$ 0.51 on Incheon, 1.50 $\pm$ 0.13 on Daejeon, and 0.92 $\pm$ 0.24 on Kongju. Correlations were 0.675 (p<0.05) between Cu and Cd, 0.663(p<0.05) between Cu and Zn, and 0.477 between Cd and Pb. In conclusion, Among heavy metals in the fallout dust deposits at schools, Cu and Zn were the highest levels at Incheon, Cd and Pb were the highest levels at Daejeon.

• 암석학회지
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• 제20권4호
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• pp.243-250
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• 2011

백두산 화산으로부터 분화된 것으로 추정되는 1702년의 역사기록을 화산학적 견지에서 고찰하였다. 분화지점인 백두산으로부터 140 km 떨어진 2 장소에서의 강하화산재의 등층후선을 설정하여 경험식에 의하여 계산된 분출물의 최소량은 $1.2km^3$로 1702년의 백두산 분화 사건은 화산폭발지수 5에 해당하는 대규모 분화였다. 플리니안 분화에 의한, 열기를 가진 화산재구름이 바람의 영향 하에 지면 가까이 낮은 고도로 이동하면서 강하화산재가 발생 퇴적된 것을 잘 묘사하고 있다. 향후 분화에 대비하여 역사기록에 대한 철저한 분석을 통한 화산의 특성 이해가 절실하다.

• Journal of Nuclear Fuel Cycle and Waste Technology
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• 제1권1호
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• pp.49-55
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• 2013

To characterize quantitatively the transport of $^{99}Tc$ and the global fallout ($^{137}Cs$, $^{90}Sr$, and $^{239+240}Pu$) for soils in Korea, the transport parameters of a convective-dispersion model, apparent migration velocity, and apparent dispersion coefficient were estimated from the vertical depth profiles of the radionuclides in soils. The vertical profiles of $^{99}Tc$ were measured from a pot experiment for paddy soil that had been sampled from a rice-field around the Gyeongju radioactive waste repository in Korea, and the vertical depth distributions of the global fallout $^{137}Cs$, $^{90}Sr$, and $^{239+240}Pu$ were measured from the soil samples that were taken from local areas in Korea. The front edge of the $^{99}Tc$ profiles reached a depth of about 12 cm in 138 days, indicating a faster movement than the fallout radionuclides. A weak adsorption of $^{99}Tc$ on the soil particles by the formation of Tc(VII) and a high water infiltration velocity seemed to have controlled the migration of $^{99}Tc$. The apparent migration velocity and dispersion coefficient of $^{99}Tc$ for the disturbed paddy soil were 2.88 cm/y and 6.3 $cm^2/y$, respectively. The majority of the global fallout $^{137}Cs$, $^{90}Sr$, and $^{239+240}Pu$ were found in the top 20 cm of the soils even after a transport of about 30 years. The transport parameters for the global fallout radionuclides were 0.01-0.1cm/y ($^{137}Cs$), 0.09-0.13cm/y ($^{90}Sr$), and 0.09-0.18cm/y ($^{239+240}Pu$) for the apparent migration velocity: 0.21-1.09 $cm^2/y$ ($^{137}Cs$), 0.12-0.7$cm^2/y$ ($^{90}Sr$), and 0.09-0.36$cm^2/y$ ($^{239+240}Pu$) for the apparent dispersion coefficient.

• 대한치과의사협회지
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• 제13권12호
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• pp.1163-1169
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• 1975

• 한국원자력학회:학술대회논문집
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• 한국원자력학회 1998년도 춘계학술발표회논문집(2)
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• pp.627-632
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• 1998

Using an ammonium oxalate-ammonium sulfate electrolyte, a simple, quantitative, and fast technique for preparing sources for analytical alpha spectrometry was developed. To determine the optimum conditions for plating plutonium, parameters such as current density .and pH of electrolyte affacting the electrodeposition of the plutonium have been investigated. An optimized electrodeposition step for the determination of plutonium has been validated with a result of application to IAEA-Reference Soils. The new method of fallout Pu determination has been applied to environmental samples such as soil, sediment and moss samples in Korea.