• Title/Summary/Keyword: Soil Radioactivity

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Derivation of preliminary derived concentration guideline levels for surface soil at Kori Unit 1 by RESRAD probabilistic analysis

  • Byon, Jihyang;Park, Sangjune;Ahn, Seokyoung
    • Nuclear Engineering and Technology
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    • v.50 no.8
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    • pp.1289-1297
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    • 2018
  • Preliminary surface soil Derived Concentration Guideline Levels (DCGLs) were derived conforming to the Multi-Agency Radiation Site Survey and Investigation Manual (MARSSIM) procedure for the site release and reuse of Kori Unit 1 in Korea. Based on the decommissioning experiences of the U.S. nuclear power plants, a suite of residual radionuclides was determined, and uncertainties contributed to the resultant dose by the input parameters were quantified via the sensitivity analysis of parameters. The peak of the mean dose was obtained via the probabilistic analysis of the RESRAD (RESidual RADioactivity)-ONSITE code. Consequently, $DCGL_w$ of Kori Unit 1 in accordance with two scenarios, industrial worker and residential farmer scenario, were derived and the results were compared respectively with other NPPs. It could be used as a basic guideline for establishing regulatory standards for reuse planning, designing the site characterization surveys and implementing final status survey (FSS).

Uptake of the Fresh and Aged Residues of Carbofuran by Rice Plants from Soil (침투성(浸透性) 살충제(殺蟲劑) Carbofuran 토양(土壤) 잔류물(殘留物)의 벼에 의(依)한 흡수(吸收))

  • Lee, Jae-Koo;Kyung, Kee-Sung;Wheeler, W.B.
    • Korean Journal of Environmental Agriculture
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    • v.8 no.2
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    • pp.103-118
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    • 1989
  • In order to investigate the uptake of the systemic insecticide, carbofuran, 2,3-dihydro-2,2-dimethyl-7-benzofuranyl-N-methyl(arbamate) residues, fresh and aged, by rice plants, they were grown for 42 days in soils containing freshly treated (T-1), 3-month-aged (T-2), and 6-month-aged residues (T-3). The amounts of $^{14}CO_2$ evolved from $^{14}C-carbofuran$ during the 3-and 6-month aging in soil (temp. $22{\pm}1^{\circ}C$ ; moisture, 50% of the maximum water-holding capacity) were 8.9 and 26.7% of the original radioactivity applied, respectively. Mineralization of $^{14}C-carbofuran$ in soil to $^{14}CO_2$ during 42 days of rice growing was 4.4% (T-1), 11.0% (T-2), and 15.7 (T-3). The methanol extract of the 3-and 6-month-aged soils revealed that 3-keto carbofuran phenol (2,3-dihydro-2,2-dimethyl-3-oxo-7-benzofuranol) was the major metabolite, where as 3-hydroxy carbofuran (2,3-dihydro-2,2-dimethyl-3-hydroxy-7-benzofuranyl-N-methylcarbamate) turned out to be the major metabolite in the shoots by the enzymatic cleavage of the possible conjugate present in the methanol extract. Volatilization of $^{14}C-carbofuran$ in soil during 3-and 6-month-aging, and 42 days of rice growing was 0.026, 0.05, and 0.012-0.018% of the applied radioactivity, respectively. The $^{14}C-radioactivity$ which was absorbed from the soils by rice plants during 42 days of the growing period and persisted in rice plant tissues was 26.8, 21.4, and 10.3% in T-1, T-2, and T-3, respectively. The non-extractable bound residues were 8.3, 37.9, and 54.6% of the originally applied carbofuran in T-1. T-2, and T-3, respectively. The small translocation of $^{14}C-radioactivity$ in T-3 upwards suggests that major metabolite 3-keto carbofuran phenol is conjugated in roots and the low recovery in T-1 indicates the loss of carbofuran from the shoots.

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Radioactivity Analysis of Soils Stored in KAERI for Regulatory Clearance (연구소 내 저장 중인 토양의 규제해제를 위한 방사능 분석)

  • Hong D.S.;Kim T.K.;Kang I.S.;Cho H.S.;Shon J.S.
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.06a
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    • pp.161-166
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    • 2005
  • In KAERI, about 3,100 drums containing soil have been stored. The soils were generated from the decommissioning process of Seoul office in 1988. Those soils occupy about $27\%$ of the capacity of the radioactive waste storage facility and make it difficult to maintain the storage facility. The major radioactive nuclides contained in the soils were expected to be Co-60 and Cs-137. As 16 years have passed, the radioactivity of those nuclides have decayed a lot. In this study, as a basis of regulatory clearance, radionuclides and radioactivity concentration of soils were analyzed. As a result, there are only Co-60 and Cs-137 in soils as ${\gamma}-emitters$. The total concentration of ${\gamma}-emitters$ in soil is analyzed as about $0.01\;{\sim}\;0.12$ Bq/g. As the soils are expected to be regulatory cleared in 2009, those concentrations will decay to be less than 0.1 Bq/g. This concentration can be meet the regulatory criteria suggested by IAEA. The regulatory clearance will be proceeded based on not only the assessment results of environmental influence but also related regulations.

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A Study on the Statistical Representativeness of Samples taken from Radioactive Soil (방사성 토양폐기물 시료의 통계적 대표성에 관한 연구)

  • Cho Han-Seok;Kim T.K.;Lee K.M.;Ahn S.J.;Shon J.S.
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2005.06a
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    • pp.151-157
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    • 2005
  • For the treatment of regulatory clearance of the soils, a procedure for the radionuclides and radioactivity concentration analysis is under development. A strategy for soil sampling including random sampling after homogenization and standardization was set up. Statistical representativeness is considered for not only sampling strategy but also sample size. In this study, designed sample size was designed with confidence interval and error bound of soil using the pilot samples which were taken following the sampling strategy.

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Anaerobic Metabolism of the Herbicide, Butachlor in soil (토양중에 있어서 제초제 Butachlor의 혐기적 대사)

  • Lee, Jae-Koo;Minard, Robert D.;Bollag, Jean-Marc
    • Applied Biological Chemistry
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    • v.25 no.2
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    • pp.83-92
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    • 1982
  • In an anaerobic incubation of uniformly ring-labeled $^{14}C-butachlor$ in two Korean soils for 3 months, very little $^{14}CO_2$ and volatile products were measured. In soil A, 77.52 and 45.36% of the sterile and viable soil radioactivity, respectively, were methanol-extractable and the rest were adsorbed in soil; whereas in soil B, 58.85 and 37.23%, respectively, were methanol-extractable and the rest remained in soil. The adsorption of $^{14}C-butachlor$ depends on the characteristics of the soils. The major metabolite was 2,6-diethyl-N-(butoxymethyl) acetanilide. 2,6-Diethylaniline and 2,6-diethylacetanilide turned out to be the minor metabolites on GLC-MS.

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Distribution of 90Sr Activities in the Environmental Radiation Samples of Jeju Island, Korea

  • Han, Chung Hun;Park, Youn Hyun;Lee, Young Gyu;Park, Jae Woo
    • Journal of Radiation Protection and Research
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    • v.41 no.4
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    • pp.418-423
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    • 2016
  • Background: This work was to get information about $^{90}Sr$ contamination of the environment by using soil and moss from selected areas in Jeju Island, Korea. Materials and Methods: The activities of $^{90}Sr$ in soil and moss samples were investigated at nine locations of Jeju island, Korea. The soil samples have been collected at 4 sites of Jeju island during June to August of 2013, analyzed for vertical distribution of $^{90}Sr$ activities. The moss samples have been collected at 5 sites of Jeju island during November of 2011 to June of 2012, and analyzed for radioactive $^{90}Sr$. Results and Discussion: The $^{90}Sr$ vertical concentrations in the investigated soil samples were 2.77 to $18.24Bq{\cdot}kg^{-1}$ in eastern part, 1.69 to $18.27Bq{\cdot}kg^{-1}$ in northern part, 3.76 to $13.46Bq{\cdot}kg^{-1}$ in the western part and 1.09 to $8.70Bq{\cdot}kg^{-1}$ in the southern part of the Mt. Halla in Jeju island, respectively. Activities of $^{90}Sr$ show the highest value at the surface soil and decrease with depth. The activity concentration measured was in the range of 79.6 to $363Bq{\cdot}kg^{-1}$ -dry moss. Conclusion: This material is expected to be basis reference for survey of environmental radioactivity in Jeju Island.

Behavior of the soil residues of the fungicide hexaconazole in a rice plants-grown microecosystem (pot) (살균제 hexaconazole 토양잔류물의 벼 재배 microecosystem(pot)중 행적)

  • Kyung, Kee-Sung;Lee, Byung-Moo;Lee, Jae-Koo
    • The Korean Journal of Pesticide Science
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    • v.8 no.3
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    • pp.198-209
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    • 2004
  • In order to elucidate the behavior of the fungicide hexaconazole in soil and rice plants, rice plants were grown for 42 days in a microecosystem (pot) containing fresh and 28 day-aged soil residues of $[^{14}C]$hexaconazole. The amount of $^{14}CO_2$ evolved during 28 days of aging was 0.11 % of total $^{14}C$-radioactivity treated and the averaged weekly degradation rate was 0.03%. Mineralization rates for 42 days of rice cultivation on fresh and aged paddy soils were 0.67% of the total $^{14}C$ in case of non-rice planting on aged soil and 1.17% in case of rice planting on aged soil, whereas 1.25% in non-rice planting on fresh soil and 1.72% in case of rice planting on fresh soil, suggesting that the amounts of $^{14}CO_2$ were evolved higher from fresh soils than aged ones and from rice-planting soils than non-planting ones. The amounts of volatiles collected were very low as background levels. Most of $^{14}C$-Radioactivity was remained in soil after 42 days of rice cultivation and $^{14}C$ absorbed through rice roots was distributed more in shoots than roots and translocated into the edge of shoots of rice plants. Amounts of non-extractable $^{14}C$ in soils were higher in rice planted soil than in non-planting soil. The distribution of non-extractable $^{14}C$ was increased in the order of humin>fulvic acid>humic acid. The amounts of $^{14}C$ translocated into rotational crop Chinese cabbage were 2.36 and 3.69% of the total $^{14}C$ in case of rice planted soil containing fresh and aged residues, respectively, suggesting that small amounts of $[^{14}C]$hexaconazole and its metabolite(s) were absorbed and their bound residues were more available than their fresh ones to Chinese cabbage.

Measurement and Monte Carlo Simulation evaluation of a Compton Continuum Suppression with low level soil Sample (저준위 토양시료를 이용한 콤프턴 연속체 억제의 측정 및 몬테카롤로 시뮬레이션 평가)

  • Jang, Eun-Sung;Lee, Hyo-Yeong
    • Journal of the Korean Society of Radiology
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    • v.12 no.2
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    • pp.123-131
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    • 2018
  • This study compared PENELOPE with measured values from low energy peak to high energy peak to reduce peak to compton ratio and continuum background spectrum using $^{60}Co$, $^{137}Cs$ and mixed volume source. In addition, the change in backscattering and compton edge efficiency was compared with that of PENELOPE through changes in the vicinity of low energy. The results from the mixed volume source are applied to the soil samples to determine how much the minimum detection limits of the soil samples are reduced in the suppression and unsuppressed mode. The compton suppression of the low energy region of $^{60}CO$ (1,173 keV) was considerable, and the Compton edge RF for the $^{137}Cs$ (661 keV) peak was 2.8. In particular, the $^{60}Co$ source emits coincidence gamma rays of 1,173.2 keV and 1,332.5 keV, so compton inhibition was reduced by approximately 21%. RF of compton edges of 1,173 keV and 1,332 keV emitted from a $^{60}Co$ source was 3.2 and 3.4, and the peak to compton edge ratio was improved to 8: 1. And Compared with Penelope, the uncertainty was well within 2%. In compton unsuppressed mode, MDA values of 661 keV, 1,173 keV and 1,332 keV were 0.535, 0.173 and 0.136 Bq/kg, respectively, but decreased in compton suppressed mode to 0.121, 0.00826 and 0.00728 Bq/kg. Thus, Compton suppressed could reduce the background radioactivity and the radioactivity contained in the detector itself.

Leaching behaviour of the systemic insecticide carbofuran and the herbicide pretilachlor in soil columns (토양 column중 침투성 살충제 carbofuran과 제초제 pretilachlor의 용탈)

  • Lee, Jae-Koo;Kyung, Kee-Sung;Jung, In-Sang;Ahn, Ki-Chang;Kwon, Jeong-Wook
    • The Korean Journal of Pesticide Science
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    • v.2 no.2
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    • pp.59-67
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    • 1998
  • 토양중 침투성 살충제 carbofuran과 제초제 petilachlor의 용탈행적을 구명하기 위하여 물리화학적 성질이 상이한 2종의 논토양으로 충전된 토양 column (내경 5cm ${\times}$ 길이 30cm)에 $^{14}C$-표지 화합물을 각각 처리한 후 벼 (Oryza sativa L.)를 생육시키면서 벼를 심지 않은 경우를 대조구로 하여 8주 동안 주당 95.2 ml씩 용탈시켰다. Carbofuran의 경우 토양 column에서 용탈된 $^{14}C$ 방사능의 양은 벼를 재배하지 않은 토양 A와 B에서 각각 총처리 방사능의 74.8와 92.3%였으며, 벼를 재배한 토양에서는 각각 45.1%와 69.7%였다. 반면에 petilachlor의 경우 벼를 재배한 토양 column에서는 각각 총처리 방사능의 2.4%와 5.0%가 용탈되었으며, 벼를 재배한 경우는 각각 3.1%와 8.2%가 용탈되었다. 토양에 처리한 [$^{14}C$]화합물 모두 벼의 생육유무에 관계없이 양이온치환용량, 유기물 및 점토의 함량이 적은 토양 B에서 $^{14}C$ 방사능의 용탈이 증가되었다. 토양 column중 carbofuran의 이동성은 매우 높은 반면에 petilachlor는 매우 낮았으며, 이는 그들의 토양흡착과 수용성에 기인된 것으로 판단된다.

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Analysis of $^{89}Sr,\;^{90}Sr$ in Soil Sample Using Crown Ether/Chloroform Solvent Extraction Method (Crown Ether/Chloroform 용매추출법을 이용한 토양시료중의 $^{89}Sr,\;^{90}Sr$ 분석)

  • Hong, Kwang-Hee;Choi, Yong-Ho;Kim, Sang-Bog;Lee, Myong-Ho;Park, Hyo-Guk;Choi, Kun-Sik;Kim, Sam-Rang;Lee, Chang-Woo
    • Journal of Radiation Protection and Research
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    • v.21 no.1
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    • pp.9-16
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    • 1996
  • For the determination of radiostrontium, $^{89}Sr\;and\;^{90}Sr$ in environmental soil sample, a solvent extraction method for the separation of Ca and Sr from matrix using crown ether was investigated. In comparison with the existing fuming nitric acid method, the extraction method showed high chemical yield of strontium and provided simple and rapid analytical steps. The new analytical method applied to the determination of radiostrontium in some soil sample around a nuclear power station to show that the analytical procedure is readily applicable to the practical radioactivity monitoring.

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