• Title/Summary/Keyword: 방출화학형

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Evaluation of $^{14}C$ Behavior Characteristic in Reactor Coolant from Korean PWR NPP's (국내 경수로형 원자로 냉각재 중의 $^{14}C$ 거동 특성 평가)

  • Kang, Duk-Won;Yang, Yang-Hee;Park, Kyong-Rok
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.7 no.1
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    • pp.1-7
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    • 2009

  • This study has been focused on determining the chemical composition of $^{14}C$ - in terms of both organic and inorganic $^{14}C$ contents - in reactor coolant from 3 different PWR's reactor type. The purpose was to evaluate the characteristic of $^{14}C$ that can serve as a basis for reliable estimation of the environmental release at domestic PWR sites. $^{14}C$ is the most important nuclide in the inventory, since it contributes one of the main dose contributors in future release scenarios. The reason for this is its high mobility in the environment, biological availability and long half-life(5730yr). More recent studies - where a more detailed investigation of organic $^{14}C$ species believed to be formed in the coolant under reducing conditions have been made - show that the organic compounds not only are limited to hydrocarbons and CO. Possible organic compounds formed including formaldehyde, formic acid and acetic acid, etc. Under oxidizing conditions shows the oxidized carbon forms, possibly mainly carbon dioxide and bicarbonate forms. Measurements of organic and inorganic $^{14}C$ in various water systems were also performed. The $^{14}C$ inventory in the reactor water was found to be 3.1 GBq/kg in PWR of which less than 10% was in inorganic form. Generally, the $^{14}C$ activity in the water was divided equally between the gas- and water- phase. Even though organic $^{14}C$ compound shows that dominant species during the reactor operation, But during the releasing of $^{14}C$ from the plant stack, chemical forms of $^{14}C$ shows the different composition due to the operation conditions such as temperature, pH, volume control tank venting and shut down chemistry.

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Rare Earth Element Analysis with Chromatography-Inductively Coupled Plasma Atomic Emission Spectrometry and the Comparison of Cross Flow and Ultrasonic Nebulizers (크로마토그래피-유도 결합 플라스마 원자방출 분광법을 이용한 희토류 원소들의 연속적 분석 및 직교형과 초음파분무기의 비교)

Preparation and Evaluation of Antibacterial Transdermal Device using Chitosan Matrices (키토산 매트릭스를 이용한 향균제 경피흡수제형의 제조와 평가)

  • Kim Sun Il;Na Jae Woon
    • Journal of the Korean Chemical Society
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    • v.37 no.5
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    • pp.527-536
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    • 1993

  • The characteristics of the controlled drug release were studied for biodegradable transdermal drug delivery system. A biodegradable polymeric matrix was prepared from chitosan, silver sulfadiazine, and glycerine. The release behavior of silver sulfadiazine from chitosan matrix was consistent with the Higuchi's diffusion controlled model. The release time was delayed by increasing the content of silver sulfadiazine and thickness of the matrix, whereas decreased as glycerine concentration increased. The apparent constant (K) of release rate was proportional to the content of drug or glycerine and the thickness of chitosan matrix. These results indicated that chitosan matrix shows some potential as a drug delivery system for transdermal therapeutic application.

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Development of an Axially Viewed Inductively Coupled Plasma for Atomic Emission Spectrometry and Comparison between the Detection Limits of Lead (원자방출 분광분석을 위한 수평형 유도결합 플라스마의 개발과 납 검출한계 비교)

  • Cho, Sung Il;Han, Myung Sub;Lee, Sang Hwa;Lee, Joung Hae;Woo, Jin Chun
    • Journal of the Korean Chemical Society
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    • v.41 no.6
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    • pp.292-298
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    • 1997

  • An ICP(Inductively Coupled Plasma) emission spectrometer was developed with an axially viewed ICP source incorporated by a 5-turned induction coil and a torch, outer quartz tube of which was 50 mm longer than that used in conventional ICP/AES(Inductively Coupled Plasma Atomic Emission Spectrometry). The Optimization of the system has been performed in terms of the determination of signal-to-noise ratio and background intensity at various rf powers, sample flow rates, argon gas flow rates and cut-off gas flow rates. The spectro-analytical characteristics of the spectrum obtained between 200 and 500 nm was revealed to be similar compared with a vertically viewed ICP source. The detection limit of Pb(Ⅱ) at 220.35 nm was 11 ppb which was 5 times lower than that obtained with a vertically viewed ICP source.

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Permeability of Silver Sulfadiazine through Crosslinked Chitosan Matrices (가교키토산 매트릭스를 통한 Silver Sulfadiazine의 투과)

  • Nah, Jae Woon
    • Journal of the Korean Chemical Society
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    • v.40 no.9
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    • pp.640-648
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    • 1996

  • Crosslinked chitosan was prepared from chitin after reaction with epichlorohydrin followed by deacetylation at C2-position. Epidermal releasing polymeric matrix was prepared after swelling crosslinked chitosan with distilled water and adding silver sulfadiazine and glycerine as a plasticiser. The release behavior of silver sulfadiazine from polymeric matrix was studied in pH 7.4 phosphate buffer solution by varing the drug content, glycerine concentration, and the thickness of the matrix. The drug release time was delayed by increasing the content of silver sulfadiazine and the thickness of the matrix, whereas decreased as glycerine concentration increased. The apparent constant(K) of release rate was independent upon the matrix thickness, but was proportional to the content of drug or glycerine of crosslinked chitosan matrix. These results indicated that chitosan matrix showed some potential as a drug delivery system for transdermal therapeutic application.

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