• Title/Summary/Keyword: 세슘 염

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Sorption Behavior of Cesium-137, Cerium-144 and Cobalt-60 on Zeolites (제오라이트에 대한 세슘-137, 세슘-144 및 코발트-60 흡착거동)

  • Kim, Seok-Chul;Lee, Byung-Hun
    • Journal of Radiation Protection and Research
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    • v.10 no.1
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    • pp.3-13
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    • 1985
  • The sorption behavior of some typical fission products such as Cs-137, long-lived radionuclide; Ce-144, rare-earth element; and Co-60, corrosion product on zeolite A, zeolite F-9 (faujasite) and amorphous zeolite was determined with the salt concentrations, 0.01 M- to 2.0 M- nitric acid and ammonium nitrate, and the shaking time, 15 minutes interval from 15 minute to 90 minute. Kd values were obtained through the batch experiment. In conclusion, the optimal conditions for isolation and removal of the typical radionuclides are as following: zeolite, amorphous zeolite; concentration, $0.01\;M-HNO_3\;and\;0.1\;M-NH_4NO_3$; pH4; shaking time, one hour; the most effective species, Cs-137.

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Study of the Variation of Optical Amplification Characteristics with Incident Beam Size and Temperature of a Cesium-vapor-based Optical Amplifier (세슘 원자 증기 기반 광 증폭기의 온도와 빔 크기에 따른 광 증폭 특성 연구)

  • Ryu, Siheon;Jeong, Yujae;Yeom, Dong-Il
    • Korean Journal of Optics and Photonics
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    • v.32 no.6
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    • pp.306-313
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    • 2021
  • We study the amplification properties of an optical amplifier based on a cesium-vapor cell. An optical amplification system including cesium vapor mixed with a buffer gas is built, and its amplification feature is investigated as a function of the size of the incident beam and the temperature of the cesium-vapor cell. We observe that the optical amplification properties, such as amplification factor and extraction efficiency, change significantly depending on the temperature and beam diameter of the pump and seed light. A maximum extraction efficiency of 56% is obtained when the temperature of the cesium cell is 90 ℃, with a 200-㎛ diameter of the pump (500 mW) and seed light (10 mW). The numerical simulation of the amplification properties agrees reasonably with the results obtained from the experiment.

Optimum Remediation Conditions of Vertical Electrokinetic-Flushing Equipment to Decontaminate a Radioactive Soil (방사성토양 복원을 위한 수직형 동전기-세정장치의 최적제염조건 도출)

  • Kim, Gye-Nam;Yang, Byeong-Il;Moon, Jei-Kwon;Lee, Kune-Woo
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.7 no.3
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    • pp.153-160
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    • 2009
  • Vertical electrokintic-flushing remediation equipment was developed for the remediation of a radioactive soil near nuclear facilities. An optimum reagent was selected to decontaminate the radioactive soil near nuclear facilities with the developed vertical electrokintic-flushing remediation equipment, and the optimum remediation conditions were established to obtain a higher remediation efficiency. Namely, acetic acid was selected as an optimum reagent due to its higher remediation efficiency. When the electrokinetic remediation and the electrokinetic-flushing remediation results were compared, the removal efficiency of 4.6% and the soil waste solution volume of 1.5 times were increased in the electrokinetic remediation. When the potential gradient within an electrokinetic soil cell was increased by two times (4.0 V/cm), the removal efficiencies of $Co^{2+}$ and $Cs^+$ were increased by about 4.3%($Co^{2+}$ : 98.9%, $Cs^+$ : 96.7%). Also, when the reagent concentration was increased from 0.01M to 0.05M, the removal efficiency of $Co^{2+}$ was increased but that of $Cs^+$ was decreased. Therefore, the optimum remediation conditions were that the acetic concentration was $0.01M{\sim}0.05M$, the potential gredient was 4 V/cm, the injection of reagent 2.4ml/g, and the remediation period was 20days.

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A Study on the Process Improvement of RJ-4 fuel Preparation using a Heteropoly Acid Catalyst (Heteropoly acid촉매를 이용한 RJ-4연료의 제조공정 개선연구)

  • Jeong Byung-Hun;Han Jeong-Sik;Choi Chang-Sun;Hong Myung-Pyo
    • Proceedings of the Korean Society of Propulsion Engineers Conference
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    • 2005.11a
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    • pp.229-232
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    • 2005
  • The study on the improvement of manufacturing process of RJ-4 liquid fuel that have high flash point, was carried out. In preparing of RJ-4 using commercially available MCPD, 1st, 2nd hydrogenation and isomerization reaction were enabled 1 step continuous process by combined use of heteropoly phosphoroustungstic cesium salt catalyst and 2nd stage-heat-controllable reactor. Also when heteropolyacid cesium salt was used as a isomerization catalyst instead of aluminum chloride, formation rate of exe-THDMCPD was higher, the catalyst could be easily separable from product and there was no production of waste acid, so this new reaction condition was confirmed as the environment friendly process.

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Measurements of Separation Properties of AM, ARM Oxidesin Molten LiC1 (AM, AEM 산화물들의 용융 LiC1에서의 분리 물성 측정)

  • 오승철;박병흥;강대승;서중석;박성원
    • Proceedings of the Korean Radioactive Waste Society Conference
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    • 2003.11a
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    • pp.363-367
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    • 2003
  • Much attention has been given to an electrochemical reduction process for converting uranium oxide to uranium metal in molten salt. The process has the versatility of being adopted for reducing other actinide and rare-earth metals from their oxides. Using the metal oxide to be reduced as a integrated cathode designed originally and inert conductors as anodes, oxygen anions are removed from the cathode and oxidized at the surface of the anodes in a molten salt cell. However, the electrochemical properties of alkali and alkali-earth metal oxides in molten salt have not been investigated thoroughly, which made the process incomplete when it is considered as a unit process in a back-end fuel cycle. It is well known that cesium and strontium Isotopes in spent fuel are main contributors for head load. The properties of cesium, strontium, and barium oxides such as the dissolution rates and reduction potentials in molten LiC1 dissolving $Li_2O$ are examined.

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Development of Electrokinetic-Flushing Equipment for a Remediation of Soil Contaminated with Radionuclides (방사성오염토양 제염을 위한 동전기세정장치 개발)

  • Kim, Gye-Nam;Jung, Yun-Ho;Lee, Jung-Joon;Moon, Jei-Kwon;Jung, Chong-Hun;Chung, Un-Soo
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.6 no.1
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    • pp.1-9
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    • 2008
  • This study examined the effect of an electrokinetic-flushing remediation for a soil of a high permeability. The soil was sampled from the site around a research atomic reactor which had high hydro-conductivities due to a high content of sand in the soil. The flow rate of the washing reagent was fast at the beginning but it was reduced as time lapsed. In the case of using citric acid as a washing reagent, the flow rate was fastest, 78.7 ml/day. The removal efficiencies of $Co^{2+}$ and $Cs^+$ from a soil cell with acetic acid were the highest, which were 95.2% and 84.2% respectively. The soil waste-solution volume generated from the electrokinetic remediation was reduced to about 1/20 of that from the soil washing remediation. Meanwhile, the electrokinetic-flushing method enhanced the removal efficiencies of $Co^{2+}$ and $Cs^+$ from the soil by about 6% and 2% respectively, compared to those by the electrokinetic method. Consequently, it was found that the electrokinetic-flushing method was more effective for the remediation of a soil with a high permeability.

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Direct Conversion of Cellulose into Polyols over Pt/CsxH3-xPW12O40

  • You, Su Jin;Baek, In Gu;Park, Eun Duck
    • Clean Technology
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    • v.19 no.1
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    • pp.13-21
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    • 2013
  • The hydrogenolysis of cellulose into polyols was examined over Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalysts containing different Cs fractions. The surface area and Pt dispersion of Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalysts were found to increase with Cs content. Similar polyol yields were obtained over Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalysts irrespective of their Cs content. The catalytic activity of Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ was comparable to that of Ni/W/SBA-15 and combined catalytic systems such as Pt/AC+$H_3PW_{12}O_{40}$ and Pt/AC + $Cs_{3.0}PW_{12}O_{40}$. Some polyanion species were found to leach from the Pt/$Cs_xH_{3-x}PW_{12}O_{40}$ catalyst during the course of the reaction.

Precipitation behaviors of Cs and Re(/Tc) by NaTPB and TPPCl from a simulated fission products-$(Na_2CO_3-NaHCO_3)-H_2O_2$ solution (모의 FP-$(Na_2CO_3-NaHCO_3)-H_2O_2$ 용액으로부터 NaTPB 및 TPPCl에 의한 Cs 및 Re(/Tc)의 침전 거동)

  • Lee, Eil-Hee;Lim, Jae-Gwan;Chung, Dong-Yong;Yang, Han-Beum;Kim, Kwang-Wook
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.8 no.2
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    • pp.115-122
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    • 2010
  • In this study, the removal of Cs and Tc from a simulated fission products (FP) solution which were co-dissolved with U during the oxidative-dissolution of spent fuel in a mixed carbonate solution of $(Na_2CO_3-NaHCO_3)-H_2O_2$ was investigated by using a selective precipitation method. As Cs and Tc might cause an unstable behavior due to the high decay heat emission of Cs as well as the fast migration of Tc when disposed of underground, it is one of the important issues to removal them in views of the increase of disposal safety. The precipitation of Cs and Re (as a surrogate for Tc) was examined by introducing sodium tetraphenylborate (NaTPB) and tetraphenylphosponium chloride (TPPCl), respectively. Precipitation of Cs by NaTPB and that of Re by TPPCl were completed within 5 minutes. Their precipitation rates were not influenced so much by the temperature and stirring speed even if they were increased by up to $50^{\circ}C$ and 1,000 rpm. However, the pH of the solution was found to have a great influence on the precipitation with NaTPB and TPPCl. Since Mo tends to co-precipitate with Re at a lower pH, especially, it was effective that a selective precipitation of Re by TPPCl was carried out at pH of above 9 without co-precipitation of Mo and Re. Over 99% of Cs was precipitated when the ratio of [NaTPB]/[Cs]>1 and more than 99% of Re, likewise, was precipitated when the ratio of [TPPCl]/[Re]>1.

Evaluation of Na2CO3-H2O2 Carbonate Solution Stability (Na2CO3-H2O2 탄산염 용액의 안정성 평가)

  • Lee, Eil-Hee;Lim, Jae-Gwan;Chung, Dong-Yong;Yang, Han-Beum;Kim, Kwang-Wook
    • Journal of Nuclear Fuel Cycle and Waste Technology(JNFCWT)
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    • v.9 no.3
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    • pp.131-139
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    • 2011
  • This study was carried out to examine the stability of $Na_2CO_3-H_2O_2$ carbonate solution with aging time in the dissolving solution after oxidative dissolution of U by a carbonate solution, the Cs/Re filtrate after selective precipitation of Cs and Re (as a surrogate for Tc), and the acidification filtrate after precipitation of U by acidification, respectively. The compositions of dissolving solution were not changed with ageing time, and the selective precipitation of Re and Cs was also not affected without regard to the aging time of dissolving solution. The successive removal of Cs and Re from a carbonate dissolving solution was possible. However, the recovery yield of U by acidification was decreased with increasing the aging time of the dissolving solution and the Cs/Re-filtrate, respectively, because U was converted from the uranyl peroxocarbonato complex to the uranyltricarbonate in the solution aged for a long time. Accordingly, it is effective that a dissolving solution and a Cs/Re filtrate are treated within the aging of 7 days, respectively, in order to recover U more than 99%. On the other hand, the recovery of U was carried out in order of the oxidative dissolution of U selective precipitation of Re and Cs precipitation of U by acidification. Almost all of U and a part of FP were co-dissolved in oxidative dissolution step. Over 99% of Re and Cs from the FP co-dissolved with U could be removed by a TPPCl (tetraphenylphosphonium chloride) and a NaTPB (sodium tetraphenylborate), respectively. U was precipitated nearly 100% by acidification to pH 4. Therefore, it was confirmed that the validity of recovery of U by precipitation methods from a SF (spent fuel) in the $Na_2CO_3-H_2O_2$ solution.