• Title/Summary/Keyword: $^{226}Ra$

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The Controlling factors of Ra Isotopes in Masan Bay (마산만에서 Ra 동위원소의 농도를 결정하는 인자)

  • Kim Young Ill;Chung Chang Soo;Kim Suk Hyun;Moon Duk Soo;Park Jun Kun;Seo Sung Mo;Choi Jun Sun;Yang Dong Beom;Hong Gi Hoon
    • Journal of the Korean Society for Marine Environment & Energy
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    • v.4 no.2
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    • pp.25-34
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    • 2001
  • /sup 226/Ra and /sup 228/Ra analysis were carried out at the representative station of Masan Bay from May to August, 1999. The high activities of /sup 226/Ra and /sup 228/Ra in the surface water were appeared in rainy season (August, 1). However, there is no significant variation in concentrations in the other season. A high negative linear correlation between /sup 226/Ra activities and salinity in the surface water suggests that /sup 226/Ra activity in the surface water was controlled by simple mixing between the two end-members low salinity high /sup 226/Ra activity water of inner Bay and a high salinity low /sup 226/Ra activity water of the continental shelf water out of Bay. /sup 226/Ra activities below the surface mixed layer were higher than those of expected level from the /sup 226/Ra versus salinity. And also /sup 228/Ra//sup 226/Ra ratios in the bottom water were lower compared to those in surface water due to the presence of potential source of /sup 226/Ra below the surface mixed layer. However, it is known that /sup 228/Ra compared to /sup 226/Ra is enriched in bottom sediments and pure water. Therefore, the most probable sources for low /sup 228/Ra//sup 226/Ra activity ration is submarine ground water discharge. Further studies are required to quantify the various sources of /sup 226/Ra and /sup 228/Ra and their relative contributions.

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A Rapid Analysis of 226Ra in Raw Materials and By-Products Using Gamma-ray Spectrometry (감마분광분석을 이용한 원료물질 및 공정부산물 중 226Ra 신속분석방법)

  • Lim, Chung-Sup;Chung, Kun-Ho;Kim, Chang-Jong;Ji, Young-Yong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.15 no.1
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    • pp.35-44
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    • 2017
  • A gamma-ray peak of $^{226}Ra$ (186.2 keV) overlaps with one of $^{235}U$ (185.7 keV) in a gamma-ray spectrometry system. Though reference peaks of $^{235}U$ can be used to correct the peak interference of $^{235}U$ in the analysis of $^{226}Ra$, this requires a complicated calculation process and a high limit of quantitation. On the other hand, evaluating $^{226}Ra$ using the correction constant in the overlapped peak can make a rapid measurement of $^{226}Ra$ without the complicated calculation process as well as overcome the disadvantage in the indirect measurement of $^{214}Bi$, which means the confinement of $^{222}Rn$ gas in a sample container and a time period to recover the secular equilibrium. About 93 samples with 6 species for raw-materials and by-products were prepared to evaluate the activity of $^{226}Ra$ using the correction constant. The results were compared with the activity of $^{214}Bi$, which means the indirect measurement of $^{226}Ra$, to validate the method of the direct measurement of $^{226}Ra$ using the correction constant. The difference between the direct and indirect measurement of $^{226}Ra$ was generally below about ${\pm}20%$. However, in the case of the phospho gypsum, a large error of about 50% was found in the comparison results, which indicates the disequilibrium between $^{238}U$ and $^{226}Ra$ in the materials. Application results of the contribution ratio of $^{226}Ra$ were below about ${\pm}10%$. The direct measurement of $^{226}Ra$ using the correction constant can be an effective method for its rapid measurement of raw materials and by-products because the activity of $^{226}Ra$ can be produced with a simple calculation without the consideration of the integrity of a sample container and the time period to recover the secular equilibrium.

Determination of $^{226}Ra$ Isotope in the Leachate around Phosphogypsum Stack Using Ethylenediaminetetraacetic Acid (EDTA) (Ethylenediaminetetraacetic acid (EDTA)를 이용한 인산석고 야적장 침출수 중의 $^{226}Ra$ 분석법 개발)

  • Kim, Geun-Ho;Kim, Yong-Jae;Chang, Byung-Uck
    • Journal of Radiation Protection and Research
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    • v.36 no.4
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    • pp.223-229
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    • 2011
  • Ba is the most useful element to get the $Ba(Ra)SO_4$ precipitate. However, when the high concentrations of ions such as sulfate, calcium are existed in the leachate of phosphogypsum stack, it is difficult to get the $Ba(Ra)SO_4$ precipitate. Since this reason, the developed method for the Ba coprecipitate using EDTA was performed to determine the $^{226}Ra$ concentration in the high sulfate sample. The average concentration of $^{226}Ra$ in a leachate of phosphogypsum using this method was 0.102 $Bq{\cdot}kg^{-1}$ and the minimal detectable activity is 3.4 $mBq{\cdot}kg^{-1}$. The $mBq{\cdot}kg^{-1}$ method was 0.102 $Bq{\cdot}kg^{-1}$ and the minimal detectable activity is 3.4 $mBq{\cdot}kg^{-1}$. The $^{226}Ra$ stock solution and the CRM (Certified Reference Material) were analyzed to verify this method. In analyzed $^{226}Ra$ stock solution, bias with added concentration was approximately 1% and the correlation curve between $^{226}Ra$ concentration in simulated standard sample and measured $^{226}Ra$ concentration showed good agreement with a correlation coefficient ($R^2$) of 0.99. In analyzed CRM, maximum bias with reference value was 5.8% (k=1) and the analytical results were in good agreement with the reference value.

A Study of $^{222}Rn\;and\;^{226}Ra$ Analysis in the Groundwater by LSC (액체섬광계수기에 의한 지하수중의 $^{222}Rn$$^{226}Ra$ 분석법 연구)

  • Woo, Hyung-Joo;Yoon, Yoon-Yeol;Cho, Soo-Young;Chun, Sang-Ki
    • Journal of Radiation Protection and Research
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    • v.20 no.4
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    • pp.275-283
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    • 1995
  • PERALS(Photon Electron Rejecting Alpha Liquid Scintillation) spectrometry coupled with solvent extraction method has been set up for the analysis of $^{222}Rn\;and\;^{226}Ra$ in the groundwater. This analytical method offers low background, better energy resolution and lower quenching problem than the other techniques. By the analysis of NIST SRM 4966 $^{226}Ra$ standard, the analytical accuracy and precision were found to be 3% and 1%, respectively, and the relative standard deviation of the recovery of Rn extraction between pH2 and pH10 was 7%. Detection limits of $^{222}Rn$ and $^{226}Ra$ for 10 hours counting were counted to be $0.42 pCi/{\iota}\;and\;0.016 pCi/{\iota}$, respectively. For the test analysis of $^{222}Rn\;and\;^{226}Ra$ in the graundwater, hot spring water samples of 17 regions were analyzed. The concentration of $^{222}Rn$ were in the range of $90{\sim}5200pCi/{\iota}$ and average value was $1470pCi/{\iota}\;^{226}Ra$ concentration showed a peak value of $97.9pCi/{\iota}$ in a Kangwon region, but the average value was $1.14pCi/{\iota}$ except that region.

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Feasibility about the Direct Measurement of 226Ra Using the Gamma-Ray Spectrometry (감마분광분석을 이용한 226Ra의 직접 측정방법에 대한 적용성 평가)

  • Ji, Young-Yong;Chung, Kun Ho;Lim, Jong-Myoung;Kim, Change-Jong;Jang, Mee;Kang, Mun Ja;Park, Sang Tae;Woo, Zuhee;Koo, Boncheol;Seo, Bokyun
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.12 no.2
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    • pp.97-105
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    • 2014
  • In the case of the direct measurement of $^{226}Ra$ using a HPGe gamma-ray spectrometer, the interference between gammarays with 186.21 keV of $^{226}Ra$ and 185.7 keV of $^{235}U$ should be corrected to calculate the net peak area in the energy spectrum. In general, it is very difficult to conduct peaks stripping with difference of about 0.5 keV, although a HPGe with the superior resolution is applied and the maximum channels is applied to the spectrometer. In this study, several interference correction techniques in the direct measurement were surveyed to evaluate the feasibility for the measurement of $^{226}Ra$ using the gamma-ray spectrometery. Applying the interference corrections to the analysis of raw materials and by-products, the method validation for the direct measurement of $^{226}Ra$ was conducted by evaluating the measurement uncertainty, linearity, and range. As a result, the optimum method of the interference correction was selected by comparing with the indirect measurement of which progenies of $^{226}Ra$, such as $^{214}Pb$ and $^{214}Bi$, were analyzed in the secular equilibrium state.

Distributions of $^{226}Ra$\;and\;^{228}Ra$in the Surface Waters of East Sea of Korea (한국 동해 표층수중 $^{226}Ra$$^{228}Ra$의 농도분포)

  • YANG Han-Soeb;KWON Yeoung-Ann;KIM Gue-Buem;KIM Seong-Soo
    • Korean Journal of Fisheries and Aquatic Sciences
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    • v.25 no.5
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    • pp.399-405
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    • 1992
  • Using $MnO_2-coated$ fiber extraction and gamma counting techniques, we measured the distributions of $^{226}Ra$\;and\;^{228}Ra$ in the surface waters at 14 stations of East Sea of Korea in September, 1988. The concentrations of $^{226}Ra$\;and\;^{228}Ra$ in the surface waters ranged $70-110\;dpm/10^3l$ and 102=232 $dpm/10^3l$, respectively. In general, the concentrations of Ra isotopes were shown higher in the coastal and southern stations than those in the outer and northern stations in our observed area. Also, the concentrations of Ra isotopes in the study area were significantly higher than values in the other area of the East Sea and Kuroshio surface water, but much lower than the concentrations in the surface water of Yellow Sea reported previously. There was an inverse relationship between the $^{226}Ra/^{228}Ra$ ratio and salinity in the surface waters of Kuroshio, Yellow Sea and East Sea of Korea. This indicates that the continental shelf waters such as Yellow Sea and East China Sea are main source of Ra isotopes in surface waters of the East Sea of Korea.

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Natural Radioactivity of Soils by Bed Rocks Distributed in the Keum River Area (금강유역 기반암 토양의 자연방사능 특성)

  • Lee, Kil-Yong;Yoon, Yoon-Yeol;Cho, Soo-Young;Lee, Jung-Hwa;Lee, Jin-Soo;Koh, Kyung-Seok;Kim, Yong-Je
    • Journal of Soil and Groundwater Environment
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    • v.14 no.2
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    • pp.10-16
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    • 2009
  • Characteristics of natural radioactivity were investigated for soils collected from seven sites of different bed rocks distributed in the Keum River area of Korea by the use of a Gamma-ray spectrometry. Specific activity (SA) and SA ratio (SAR) of typical naturally occurring radioactive nuclide such as $^{226}$Ra, $^{228}$Ac and $^{40}$K were determined for the soil samples. The SA values of $^{226}$Ra, $^{228}$Ac and $^{40}$K in 41 soils of 7 sites are 26.7-485 (74.2 ${\pm}$ 72.2), 30.9-157 (90.7 ${\pm}$ 32.7) and 203-1558 (990 ${\pm}$ 203) Bq/kg, respectively. The SA of $^{226}$Ra has very different values by the soils and the sites. Especially the SA of $^{226}$Ra in a soil sample of Ogcheon site is 485 Bq/kg while most SA of 41 soil samples are < 100 Bq/kg. SA of $^{228}$Ac has a little different values with the soils and sites, however the SA of $^{40}$K has almost constant values in all soil samples. The SAR values of $^{26}$Ra/$^{228}$Ac, $^{226}$Ra/$^{40}$K and $^{228}$Ac/$^{40}$K in 41 soils of 7 sites are 0.343-6.11 (0.865 ${\pm}$ 0.883), 0.0258-0.759 (0.0814 ${\pm}$ 0.1l17) and 0.0373-0.178 (0.0945 ${\pm}$ 0.0373), respectively. The SARs of $^{226}$Ra/$^{228}$Ac and $^{226}$Ra/$^{40}$K have very different values by the soils and the sites, however the SAR of $^{228}$Ac/$^{40}$K has a little difference by the soil and sites.

Evaluation of 226Ra analysis methods using a gamma-ray spectrometer and a liquid scintillation counter (감마선분광분석기와 액체섬광계수기를 이용한 226Ra 분석법 비교 연구)

  • Ju, Byoung Kyu;Kim, Moon Su;Kim, Hyun Koo;Kim, Dong Su;Cho, Sung Jin;Yang, Jae Ha;Park, Sun Hwa;Kim, Hyoung Seop;Kwon, Oh Sang;Kim, Tae Seung
    • Analytical Science and Technology
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    • v.28 no.3
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    • pp.228-235
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    • 2015
  • The efficiency and applicability of the solid phase extraction disk method in a 226Ra analysis were examined by the gamma ray spectrometer (GRS) method using a Marinelli beaker and the liquid scintillation counter (LSC) method for groundwater. The recovered 226Ra, which was filtered by the solid phase extraction disk, was analyzed using gamma ray spectrometer The disks, which were pretreated for caulking the daughter nuclide, were sealed with polyethylene film. Distilled water was used for the blank value of the 226Ra activity. The recovery values of 214Bi and 214Pb in the solid phase extraction disk, which used 226Ra standard material, were 80% (295.21 Kev) and 104% (351.92 Kev), respectively, which were higher than 75% determined by the LSC. The injection of nitrogen gas into the measuring chamber reduced the interference values by about 10%. The detection limits of the 226Ra activity in a blank sample of 5 L were 0.17~0.40 pCi/L after 80,000 seconds of measuring time. The relationship of the 226Ra activity in the solid phase extraction disk method and in the LSC method in seven groundwater samples showed a correlation coefficient value 0.987, which implies the applicability of the solid phase extraction disk method. The results showed that 226Ra activity in groundwater using the solid phase extraction disk method has the following benefits: simple pretreatment, time saving, high recovery values, a low detection limit, and so on. Compared with the LSC method and the GRS method using the Marinelli beaker for the 226Ra analysis, the solid phase extraction disk method could be useful in groundwater samples with low levels of activities of radionuclides because the method is not restricted by the volume of the sample.

Study of the determination of 226Ra in soil using liquid scintillation counter (액체섬광계수기를 이용한 토양 중 226Ra 분석 방법 연구)

  • Jung, Yoonhee;Kim, Hyuncheol;Chung, Kun Ho;Kang, Mun Ja
    • Analytical Science and Technology
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    • v.29 no.2
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    • pp.65-72
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    • 2016
  • This study presented an analytical method for detecting radium in soils using a liquid scintillation counter (LSC). The isotope 226Ra was extracted from soil using the fusion method and then separated from interfering radionuclides using the precipitation method. Radium was coprecipitated as sulfate salts with barium (Ba) and then converted into Ba(Ra)CO3, which is soluble in an acidic solution. The isotope 222Rn, the decay progeny of 226Ra, was trapped in a water immiscible cocktail and analyzed by LSC. The pulse shape analysis (PSA) level was estimated using 90Sr and 226Ra standard solutions. The figure of merit was the highest at PSA 80, while the alpha spillover was the lowest at PSA 80. The counting efficiency was 243 ± 2% in a glass vial. This analytical method was verified with International Atomic Energy Agency (IAEA) reference materials, including IAEA-312, IAEA-314, and IAEA-315. The recovery ranged from 60–82%, while the relative bias between the measured value and the recommended value was less than 10%. The minimum detectable activity was 2.1 Bq kg−1 with dry mass 1 g, the background count rate of 0.02 cpm, the recovery rate of 70% and counting time of 30 min.

Distribution of Radioactivities of $^{226,228}Ra,\;^{137}Cs$ and $^{40}K$ in Soil in Busan Area (부산지역 토양의 $^{226,228}Ra,\;^{137}Cs$$^{40}K$ 방사능 분포)

  • Seo, Bum-Kyoung;Sung, Jung-Wook;Kim, Hyun-Duck;Lee, Dae-Won
    • Journal of Radiation Protection and Research
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    • v.26 no.4
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    • pp.441-445
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    • 2001
  • In this work we investigated distribution of the natural and artificial radioactive nuclides and level of the regional background in soil in Busan. For 45 points, the environmental radioactivity concentration of Busan surface soil is $14.38{\sim}57.03\;(mean\;:\;33.95)\;Bq{\cdot}kg^{-1}$ for $^{226}Ra,\;2.41{\sim}86.58\;(mean\;:\;51.08)\;Bq{\cdot}kg^{-1}$ for $^{228}Ra,\;223.64{\sim}1332.30\;(mean\;668.51)\;Bq{\cdot}kg^{-1}$ for $^{40}K$ and $<0.33{\sim}33.37\;(mean:13.74) Bq{\cdot}kg^{-1}$ for $^{137}Cs$. Also, in order to investigate vertical distribution for radioactivity, we examined radioactive concentration with mountain height. But there was no correlation between radiaoactivity distribution and mountain height. The $^{226}Ra/^{228}Ra$ and $^{226}Ra/^{40}K$ concentration ratios were $0.68{\pm}19 %$ and $0.06{\pm}34%$, respectively.

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