• Title/Summary/Keyword: LIBD

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Detection of Colloidal Nanoparticles in KURT Groundwater by a Mobile Laser-Induced Breakdown Detection System (이동식 레이저 유도 파열 검출 장치를 이용한 KURT 지하수 내 콜로이드 나노 입자 검출)

  • Jung, Euo-Chang;Cho, Hye-Ryun;Park, Mi-Ri;Baik, Min-Hoon
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.1
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    • pp.41-48
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    • 2011
  • A mobile laser-induced breakdown detection (LIBD) system was developed for the field measurement of the size and concentration of aquatic colloidal nanoparticles sampled from Korea Atomic Energy Research Institute Underground Research Tunnel (KURT). The established LIBD apparatus is based on the optical detection of a laser-induced plasma by means of a two-dimensional optical imaging method for determining the size of nanoparticle. Calibration curve for determining the size of nanoparticle was obtained from the polystyrene reference particles of a well-defined size. The first direct application was made at KURT for investigating the particle sizes in groundwater. By comparing the size of particles in groundwater with the sizes of reference particles, the mean particle size of approximately $108{\pm}26$ nm with the concentration lower than 50 ppb was determined.

Formation of surface mediated iron colloids during U(VI) and nZVI interaction

  • Shin, Youngho;Bae, Sungjun;Lee, Woojin
    • Advances in environmental research
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    • v.2 no.3
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    • pp.167-177
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    • 2013
  • We investigated that removal of aqueous U(VI) by nano-sized Zero Valent Iron (nZVI) and Fe(II) bearing minerals (controls) in this study. Iron particles showed different U(VI) removal efficiencies (Mackinawite: 99%, green rust: 95%, nZVI: 91%, magnetite: 87%, pyrite: 59%) due to their different PZC (Point of Zero Charge) values and surface areas. In addition, noticeable amount of surface Fe(II) (181 ${\mu}M$) was released from nZVI suspension in 6 h and it increased to 384 ${\mu}M$ in the presence of U(VI) due to ion-exchange of U(VI) with Fe(II) on nZVI surface. Analysis of Laser-Induced Breakdown Detection (LIBD) showed that breakdown probabilities in both filtrates by 20 and 200 nm sizes was almost 24% in nZVI suspension with U(VI), while 1% of the probabilities were observed in nZVI suspension without U(VI). It indicated that Fe(II) colloids in the range under 20 nm were generated during the interaction of U(VI) and nZVI. Our results suggest that Fe(II) colloids generated via ion-exchange process should be carefully concerned during long-term remediation site contaminated by U(VI) because U could be transported to remote area through the adsorption on Fe(II) colloids.

Study on the Solubility of U(VI) Hydrolysis Products by Using a Laser-Induced Breakdown Detection Technique (레이저유도파열검출 기술을 이용한 우라늄(VI) 가수분해물의 용해도 측정)

  • Cho, Hye-Ryun;Park, Kyoung-Kyun;Jung, Euo-Chang;Jee, Kwang-Yong
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.5 no.3
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    • pp.189-197
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    • 2007
  • The solubility of U(VI) hydrolysis products was determined by using a laser-induced breakdown detection (LIBD) technique. The experiments were carried out at uranium concentrations in range from $2{\times}10^{-4}\;M\;to\;4{\times}10^{-6}\;M$, pH values between 3.8 and 7.0, the constant ionic strength of 0.1 M $NaClO_4$ and the temperature of $25.0{\pm}0.1^{\circ}C$. The solubility product of U(VI) hydrolysis products was calculated from LIBD results by using the hydrolysis constants selected in NEA-TDB. The solubility product extrapolated to zero ionic strength, ${\log}K^{\circ}_{sp}=-22.85{\pm}0.23$ was calculated by using a specific ion interaction theory (SIT). The spectral features of ionic species in uranium solutions were investigated by using a conventional UV-visible absorption spectrophotometer and a fluorophotometer, respectively, $(UO_2)_2(OH)_2^{2+}\;and\;(UO_2)_3(OH)_5^+$ were dominant species at uranium concentration of $2{\times}10^{-4}\;M$.

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Study on The Measurement of Corrosion Product Concentration in The Feed Water System of A Power Plant (발전소 급수계통 부식생성물 농도 측정에 관한 연구)

  • Moon, Jeon Soo;Lee, Jae Kun
    • Corrosion Science and Technology
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    • v.10 no.4
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    • pp.151-155
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    • 2011
  • The iron oxide particles could be resulted from the corrosion of the circulating water system of a power plant. Because it may be one of the trouble materials which affect the power generation efficiency due to the deposition on steam generator tube and turbine blade, the continuous observation of its concentration is very important. The laser induced break-down detection (LIBD) technology was applied to monitor continuously the concentration of corrosion products with the detection limit of ppb level. The measurement system consists of a Nd:YAG pulsed laser, a polarizing beam splitter, a flow-type sample cell, an acoustic emission sensor, a high speed data acquisition board, a personal computer, etc.. The performance test results confirmed that this technology can be effective to monitor the corrosion product concentration of the circulating water system of a power plant.