• Title/Summary/Keyword: $^{238}U$

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Determine the hazards of radioactive elements and radon gas manufacturing processes in an Egyptian fertilizer factory

  • Soad Saad Fares
    • Nuclear Engineering and Technology
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    • v.56 no.5
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    • pp.1781-1795
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    • 2024

  • This study investigated the levels of radioactivity in soil surrounding a phosphate fertilizer factory in Egypt, aiming to assess potential risks to the population exposed to radiation. Concentrations of 238U, 226Ra, 232Th, and 40K were measured in soil samples collected from two subsites: one near the factory (subsite 1) and another further away (subsite 2). Two different systems were used for measuring radioactivity, a high-purity gamma ray spectroscopy system with an HPGe detector for gamma-emitting isotopes and a CR-39 solid nuclear track detector for alpha-emitting radon gas. Subsite 1, located close to the factory, displayed significantly elevated levels of 226Ra compared to global background levels (514 and 456 Bq/kg vs. 35 Bq/kg). Additionally, the concentrations of 238U (241.06 Bq/kg vs. global average 35 Bq/kg), 232Th (16.15 Bq/kg vs. global average 30 Bq/kg), and 40K (146.36 Bq/kg vs. global average 400 Bq/kg) were all above global averages. Furthermore, a high concentration of radon gas (337.06 μSv/y) was measured at subsite 1. The strong positive correlation observed between 226Ra and 238U (0.96256) provides further evidence of potentially elevated radioactivity levels near the factory. In contrast, subsite 2, situated farther from the factory, exhibited natural radioactive background levels within international limits. Quantitative analysis revealed that gamma ray absorbed doses for 226Ra and 232Th exceeded global averages in some samples. Specifically, 226Ra doses ranged from 7.8 to 46.26 ppm (exceeding the 20 ppm global average in some cases), and 232Th doses ranged from 1.98 to 9.14 ppm (exceeding the 10 ppm global average in some cases). The concentration of 40K, however, remained within the global range (0.07%-0.69 %). The observed imbalances in the ratios of Th/U (0.17-0.24 Bq/kg and 0.73-0.24 ppm) and U/Ra (0.81-0.73 Bq/kg and 0.73-0.17 ppm), both of which are significantly lower than their respective global averages of 4 and 2.4, point towards the presence of fertilizer-derived contamination. This conclusion is further supported by the high phosphate concentrations detected in the samples. Overall, this study suggests that radioactive contamination near the phosphate fertilizer factory significantly exceeds global background levels and international limits in some cases. This raises concerns about potential risks posed to surrounding agricultural land and crops.

  • https://doi.org/10.1016/j.net.2023.12.034 인용 PDF

Geochemistry, Isotope Properties and U-Pb Sphene Age of the Jeongeup Foliated Granite, Korea (정읍엽리상화강암의 지구화학 및 동위원소 특성과 U-Pb 스핀 연대)

  • Jeong, Youn-Joong;Cheong, Chang-Sik;Park, Cheon-Young;Shin, In-Hyun
    • Journal of the Korean earth science society
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    • v.29 no.7
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    • pp.539-550
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    • 2008

  • In this paper, we investigate the geochemical and isotope properties of the Jeongeup foliated granite (hereafter, the JFG) in the Jeongeup area, aiming at establishing the movement age of the Honam shear zone by U-Pb sphene geochronology. In the AMF diagram, the JFG corresponds to the calc alkalic rock series, and belongs to the magnesia region in the diagram of silica versus $FeO^{total}/(FeO^{total}+MgO)$. Additionally, in the Rb-Ba-Sr diagram, it is classified as granodiorite and anomalous granite with distinctive negative Eu-anomaly in the REE patterns. According to the silica and trace element contents, the JFG falls on the type VAG+syn-COLG, which implies that this was formed under the circumstance of compressional continental margin or volcanic arc. $^{143}Nd/^{144}Nd$ isotope ratios range from 0.511495 to 0.511783 and $T_{DM}$ are calculated to be about $1.68{\sim}2.36Ga$. U-Pb sphene ages of the JFG are $172.9{\pm}1.7Ma$ and $170.7{\pm}2.8Ma$, based on $^{238}U-^{206}Pb$ and $^{235}U-^{207}Pb$ ages, respectively. Presumably, the dextral ductile shearing in the Jeongeup area has occurred after 173 Ma.

  • https://doi.org/10.5467/JKESS.2008.29.7.539 인용 PDF KSCI

토륨 핵연료의 핵적 타당성 연구 - 가압경수로용 탄소피막 핵연료 적용 -

  • 임재용;김명현;주형국
    • Proceedings of the Korean Nuclear Society Conference
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    • 1997.10a
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    • pp.171-176
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    • 1997

  • Th-232를 Fertile로 사용한 핵연료는 U-238을 Fertile로 사용한 핵연료보다 핵확산 저항성, 방사성 폐기물 생성면에서 유리하다. 본 연구에서는 MHTGR의 핵연료에 사용된 탄소피막 입자 기술을 토륨 핵연료에 적용하여 새로운 가압경수로용 핵연료로 개념 설계하였다. 핵연료의 설계안을 울진 3,4호기 집합체 설계안에 적용하여 해적 타당성을 살펴보았다.

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