• 제목/요약/키워드: boron analysis

검색결과 267건 처리시간 0.031초

고리 1호기의 기사용 핵연료 집합체 수송용기 설계에 관한 연구 (Design Study of A Spent Fuel Shipping Cask for Korea Nuclear Unit-1)

  • Moo Han Kim;Chang Sun Kang
    • Nuclear Engineering and Technology
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    • 제14권4호
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    • pp.196-203
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    • 1982
  • 본 논문에서는 고리 1호기의 기사용 핵연료 집합체를 수송하기 위한 Cask를 설계하였다. 이를 위하여 고리 1호기의 기사용 핵연료 집합체로부터 방출되는 감마선과 중성자를 계산하여 MORSE 및 ANISN전산 코드로써 차폐 계산을 수행하였다. 그 결과, 9개의 집합체를 동시에 수송할 수 있는 Steel Cask가 가장 적합하다는 것을 밝혔다. 이 Steel Cask에 대한 안전성을 평가하기 위하여 연료봉의 중심 온도와 복재온도를 계산하여 핵연료의 용융점보다 훨씬 낮음을 증명하였다. 또한 KENO와 MORSE전산 코드를 사용하여 임계도 계산을 수행하여 미임계 상태임을 증명하였다. 이로써 9개의 기사용 핵연료 집합체를 동시에 수송할 수 있는 Steel Cask를 간단히 설계하였다.

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밀양 고알루미나 점토광상 다이아스포아 단괴내의 진동누대 전기석의 화학적 특징 (Chemical Characterization of Oscillatory Zoned Tourmaline from Diaspore Nodule, an Aluminum-rich Clay Deposit, Milyang, South Korea)

  • 추창오;김영규
    • 한국광물학회지
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    • 제18권3호
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    • pp.227-236
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    • 2005
  • 밀양점토광상의 알루미늄이 풍부한 다이아스포아 단괴에서 열수변질 기원 전기석은 집합체나 미립으로 산출한다 대부분의 전기석 결정은 미세한 대구조가 특징적인데, 이는 열수변질 작용동안 개방계의 유체혼합과 같은 변동이 심한 환경에서 형성되었음을 지시한다. 본 전기석의 화학적 진동누대 구조의 양상은 결정축의 방향과는 무관하게 흡사한 특징을 보인다. Mg는 결정성장 초기, Fe는 후기 단계동안에 부화되었으며, Fe/Mg의 비는 규칙적으로 진동함을 보여 준다. 화학분석, 후방산란영상(BSE), X-선 화학분석도에 따르면 전기석내 진동누대구조는 Fe와 Mg 함량변화에 주로 제어되었으며 봉소함량의 기여도는 미미하다. 전기석이 다이아스포아와 딕카이트로 변질되는 것으로 볼 때 전기석은 B, Fe, Mg의 활동도가 감소하면서 이들 고알루미나 광물에 비하여 불안정해 진다. 그러므로 열수계내 알루미늄 활동도가 전기석의 안정성을 제어하는 것으로 볼 수 있다.

Cross Talk Experiment with Two-element CdTe Detector and Collimator for BNCT-SPECT

  • Manabe, Masanobu;Ohya, Ryosuke;Saraue, Nobuhide;Sato, Fuminobu;Murata, Isao
    • Journal of Radiation Protection and Research
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    • 제41권4호
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    • pp.328-332
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    • 2016
  • Background: Boron Neutron Capture Therapy (BNCT) is a new radiation therapy. In BNCT, there exists some very critical problems that should be solved. One of the severest problems is that the treatment effect cannot be known during BNCT in real time. We are now developing a SPECT (single photon emission computed tomography) system (BNCT-SPECT), with a cadmium telluride (CdTe) semiconductor detector. BNCT-SPECT can obtain the BNCT treatment effect by measuring 478 keV gamma-rays emitted from the excited state of $^7Li$ nucleus created by $^{10}B(n,{\alpha})$ $^7Li$ reaction. In the previous studies, we investigated the feasibility of the BNCT-SPECT system. As a result, the S/N ratio did not meet the criterion of S/N > 1 because deterioration of the S/N ratio occurred caused by the influence of Compton scattering especially due to capture gamma-rays of hydrogen. Materials and Methods: We thus produced an arrayed detector with two CdTe crystals to test cross talk phenomenon and to examine an anti-coincidence detection possibility. For more precise analysis for the anti-coincidence detection, we designed and made a collimator having a similar performance to the real BNCT-SPECT. Results and Discussion: We carried out experiments with the collimator to examine the effect of cross talk of scattering gamma-rays between CdTe elements more practically. As a result of measurement the coincidence events were successfully extracted. Conclusion: We are now planning to carry out evaluation of coincidence rate from the measurement and comparison of it with the numerical calculations.

전기방사에 의한 질화붕소 나노분말의 함량에 따른 질화붕소 나노섬유 합성 및 특성 평가 (Characterization and Synthesis of BN Fibers According to the Content of BN Nanopowder by Electrospinning Method)

  • 이종혁;전명표;황진아;정영근;주제욱
    • 한국전기전자재료학회논문지
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    • 제31권7호
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    • pp.455-461
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    • 2018
  • Boron nitride (BN) nanofibers were fabricated using BN nanoparticles (70 nm) by electrospinning. Morphologies such as the diameter and density of the BN nanofibers are strongly influenced by the viscosity and dispersion state of the precursor solution. In this study, the precursor solution was prepared by ball milling BN nanoparticles and polyvinylpyrrolidone (PVP, Mw~1,300,000) in ethanol, which was electrospun and then calcined to produce BN fibers. High-quality BN nanofibers were well fabricated at a BN concentration of 15 wt% with their diameters in the range of 500 nm to 800 nm; the viscosity of the precursor solution was $400mPa{\cdot}S$. The calcination of the as-electrospun BN fibers seemed to be completed by holding them at $350^{\circ}C$ for 2 h considering the TGA data. The morphologies and phases of the BN fibers were investigated by scanning electron microscopy (SEM) and X-ray diffractometry (XRD), respectively; Fourier transform infrared (FT-IR) was also used for structure analysis.

A Study on the Optimal Position for the Secondary Neutron Source in Pressurized Water Reactors

  • Sun, Jungwon;Yahya, Mohd-Syukri;Kim, Yonghee
    • Nuclear Engineering and Technology
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    • 제48권6호
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    • pp.1291-1302
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    • 2016
  • This paper presents a new and efficient scheme to determine the optimal neutron source position in a model near-equilibrium pressurized water reactor, which is based on the OPR1000 Hanul Unit 3 Cycle 7 configuration. The proposed scheme particularly assigns importance of source positions according to the local adjoint flux distribution. In this research, detailed pin-by-pin reactor adjoint fluxes are determined by using the Monte Carlo KENO-VI code from solutions of the reactor homogeneous critical adjoint transport equations. The adjoint fluxes at each allowable source position are subsequently ranked to yield four candidate positions with the four highest adjoint fluxes. The study next simulates ex-core detector responses using the Monte Carlo MAVRIC code by assuming a neutron source is installed in one of the four candidate positions. The calculation is repeated for all positions. These detector responses are later converted into an inverse count rate ratio curve for each candidate source position. The study confirms that the optimal source position is the one with very high adjoint fluxes and detector responses, which is interestingly the original source position in the OPR1000 core, as it yields an inverse count rate ratio curve closest to the traditional 1/M line. The current work also clearly demonstrates that the proposed adjoint flux-based approach can be used to efficiently determine the optimal geometry for a neutron source and a detector in a modern pressurized water reactor core.

Study on Reaction Behavior of Mg-FeB Phase for Rare Earth Elements Recovery from End-of-life Magnet

  • Sangmin Park;Dae-Kyeom Kim;Rongyu Liu;Jaeyun Jeong;Taek-Soo Kim;Myungsuk Song
    • 한국분말재료학회지
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    • 제30권2호
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    • pp.101-106
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    • 2023
  • Liquid metal extraction (LME), a pyrometallurgical recycling method, is popular owing to its negligible environmental impact. LME mainly targets rare-earth permanent magnets having several rare-earth elements. Mg is used as a solvent metal for LME because of its selective and eminent reactivity with rare-earth elements in magnets. Several studies concerning the formation of Dy-Fe intermetallic compounds and their effects on LME using Mg exist. However, methods for reducing these compounds are unavailable. Fe reacts more strongly with B than with Dy; B addition can be a reducing method for Dy-Fe intermetallic compounds owing to the formation of Fe2B, which takes Fe from Dy-Fe intermetallic compounds. The FeB alloy is an adequate additive for the decomposition of Fe2B. To accomplish the former process, Mg must convey B to a permanent magnet during the decomposition of the FeB alloy. Here, the effect of Mg on the transfer of B from FeB to permanent magnet is observed through microstructural and phase analyses. Through microstructural and phase analysis, it is confirmed that FeB is converted to Fe2B upon B transfer, owing to Mg. Finally, the transfer effect of Mg is confirmed, and the possibility of reducing Dy-Fe intermetallic compounds during LME is suggested.

SHIELDING ANALYSIS OF DUAL PURPOSE CASKS FOR SPENT NUCLEAR FUEL UNDER NORMAL STORAGE CONDITIONS

  • Ko, Jae-Hun;Park, Jea-Ho;Jung, In-Soo;Lee, Gang-Uk;Baeg, Chang-Yeal;Kim, Tae-Man
    • Nuclear Engineering and Technology
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    • 제46권4호
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    • pp.547-556
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    • 2014
  • Korea expects a shortage in storage capacity for spent fuels at reactor sites. Therefore, a need for more metal and/or concrete casks for storage systems is anticipated for either the reactor site or away from the reactor for interim storage. For the purpose of interim storage and transportation, a dual purpose metal cask that can load 21 spent fuel assemblies is being developed by Korea Radioactive Waste Management Corporation (KRMC) in Korea. At first the gamma and neutron flux for the design basis fuel were determined assuming in-core environment (the temperature, pressure, etc. of the moderator, boron, cladding, $UO_2$ pellets) in which the design basis fuel is loaded, as input data. The evaluation simulated burnup up to 45,000 MWD/MTU and decay during ten years of cooling using the SAS2H/OGIGEN-S module of the SCALE5.1 system. The results from the source term evaluation were used as input data for the final shielding evaluation utilizing the MCNP Code, which yielded the effective dose rate. The design of the cask is based on the safety requirements for normal storage conditions under 10 CFR Part 72. A radiation shielding analysis of the metal storage cask optimized for loading 21 design basis fuels was performed for two cases; one for a single cask and the other for a $2{\times}10$ cask array. For the single cask, dose rates at the external surface of the metal cask, 1m and 2m away from the cask surface, were evaluated. For the $2{\times}10$ cask array, dose rates at the center point of the array and at the center of the casks' height were evaluated. The results of the shielding analysis for the single cask show that dose rates were considerably higher at the lower side (from the bottom of the cask to the bottom of the neutron shielding) of the cask, at over 2mSv/hr at the external surface of the cask. However, this is not considered to be a significant issue since additional shielding will be installed at the storage facility. The shielding analysis results for the $2{\times}10$ cask array showed exponential decrease with distance off the sources. The controlled area boundary was calculated to be approximately 280m from the array, with a dose rate of 25mrem/yr. Actual dose rates within the controlled area boundary will be lower than 25mrem/yr, due to the decay of radioactivity of spent fuel in storage.

SSQ 프로그램을 이용한 빠른 X-선형광분석법 고찰 (The Study of Fast X-ray Fluorescence Analysis Using a SSQ Program)

  • 박용준
    • 분석과학
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    • 제11권2호
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    • pp.112-119
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    • 1998
  • 검정곡선을 작성하지않고 빠르게 분석할 수 있는 Siemens SemiQuant(SSQ) 3000 프로그램을 이용하여 여러 가지 형태의 고체 표준물질을 붕소부터 우라늄까지의 전 원소에 대해 신속한 X-선 형광분석을 하고 다양한 시료형태와 시료준비과정에 따른 정확도를 비교하였다. 시료당 75개의 원소분석에 소요되는 시간은 23분이 걸렸으며, 시료의 형태는 분말지질시료, 디스크형태의 금속시편 또는 chip형태의 금속 표준시료를 이용하였다. 분말지질시료는 압력을 가하지 않은 분말시료(loose powder)를 액체시료 측정 컵을 사용하여 mylar foil에 싸서 측정하거나 압력을 가해 펠렛형태로 만들거나 혹은 flux를 가해서 유리 bead시료를 만들거나 하여 여러 가지의 시료처리방법을 비교하였다. 금속시편의 분석결과는 분말지질시료에 비해 비교적 정확한 것으로 나타났다. 시료중의 모든 원소의 농도가 미지인 경우보다 철시편이나 스텐강과 같이 주원소의 농도범위를 대략적으로 알 수 있는 경우는 매질에 대한 매트릭스 효과를 계산해 줄 수 있기 때문에 좀더 정확한 결과를 얻을 수 있었다. 분말지질시료를 펠렛을 만들어 분석하는 경우와 유리 bead 시료를 만들어 측정하는 경우는 분말시료 그 지체 그대로 mylar foil에 싸서 측정하는 경우보다 시료준비과정이 간단하지 않고 많은 시간이 소요되지만 분석의 정확도는 더 높은 것으로 나타났다. 그러나 붕소나 탄소와 같은 가벼운 원소가 매트릭스로 존재하거나 이들의 분석이 요구되는 경우는 foil이나 헬륨기체에 의한 X-선 흡수 때문에 펠렛을 만들어 분석하는 것이 바람직하며 로듐 컴프턴 선을 이용하여 정확한 매트릭스 보정을 하였는지를 판단하였다.

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남서해안 고사리 생육지의 토양화학적 특성과 고사리식물체의 무기성분 함량 (Nutrient Contents of Bracken (Pteridium aquilinum L.) and Soil Chemical Properties of Its Habitat in the Coastal Area)

  • 이수영;박강용;박양호
    • 한국토양비료학회지
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    • 제43권5호
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    • pp.631-636
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    • 2010
  • 전남 신안군 내 고사리 재배농가들의 기술지원을 위하여 고사리 재배시험을 수행하면서 고사리 생육지의 토양특성을 조사하였고, 나물용 고사리와 성숙고사리의 식물체를 채취하여 이들의 무기성분 함량들을 분석하였으며 또한 고사리를 재배하고 있는 농가들의 포장토양과 고사리 시료들을 채취하여 분석 검토한 결과는 다음과 같다. 고사리 자생지의 토양은 pH가 5.2, 유기물 19 g $kg^{-1}$, 유효인산 20 mg $kg^{-1}$ 이었고, 치환성 칼륨, 칼슘 및 마그네슘의 함량은 각각 0.32, 2.0, 및 1.3 $cmol_c\;kg^{-1}$이 었으며, 재배지토양의 화학성은 pH가 5.7, 유기물 13 g$kg^{-1}$, 유효인산 367 mg $kg^{-1}$ 이었고, 치환성 칼륨, 칼슘 및 마그네슘의 함량은 각각 0.81, 4.0, 및 1.4 $cmol_c\;kg^{-1}$로 고사리 자생지의 토양 pH, 유효인산 및 치환성 칼슘의 함량이 매우 낮았으며, 유기물함량은 다소 높았다. 자생나물용 고사리의 무기성분 함량은 질소 4.40, 인 0.55, 칼륨 3.40, 칼슘 0.22, 마그네슘 0.32, 나트륨 0.09% 이었고, 철은 126, 망간 210, 구리 23, 아연 75, 붕소 11 mg $kg^{-1}$ 이었으며, 재배고사리의 무기성분 함량 중 질소는 5.50, 인 0.73, 칼륨 3.55, 칼슘 0.17, 마그네슘 0.28, 나트륨 0.07% 이었고, 철은 120, 망간 252, 구리 19, 아연 72, 붕소 20 mg $kg^{-1}$ 이었다. 나물용 고사리와 성숙고사리의 무기성분 함량을 비교해 보면 3요소 성분을 비롯한 대부분의 다량성분과 미량성분 모두 나물용고사리에서 높았고, 고사리가 성숙되어 갈수록 낮아지는 경향을 보였으며, 칼슘과 망간의 함량만은 성숙되어 갈수록 높아지는 경향을 나타내었다. 자생고사리와 재배고사리 간의 무기성분 함량을 비교한 결과 질소, 인, 칼륨 등 3요소 성분은 재배고사리에서 높은 경향이었고, 마그네슘 함량은 자생고사리에서 다소 높은 경향을 보였으며 그 외의 성분들은 일정한 경향을 보이지 않았다. 농가의 고사리 재배에서 재배 1년차와 2년차로 구분하여 토양의 화학성과 고사리 생육을 조사한 결과 토양화학성은 pH가 5.5~5.7, 유기물 함량이 13 g $kg^{-1}$, 유효인산이 222~367 mg $kg^{-1}$, 치환성양이온 중 칼륨 0.40~0.81, 칼슘 3.4~4.0, 마그네슘 1.4~1.6 $cmol_c\;kg^{-1}$이었고, 고사리의 생육은 1년차의 포장은 간장 (지표에서 잎가지가 있는 부분까지)이 25 cm, 입모 수는 13개 $m^{-2}$ 이었으며, 2년차 포장에서는 간장이 89 cm, 입모수가 25개로 조사 되었다.

석탄 바닥재 메움재 재활용을 위한 Field Test Cells로부터 오염물질 배출 특성 및 잠재적 영향 평가 (Leaching Characteristics and Potential Impact Assessment of Pollutants from Field Test Cells with Coal Bottom Ash as Fill Materials for Recycling)

  • 장용철;이성우;강희석;이승훈
    • 환경영향평가
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    • 제22권2호
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    • pp.135-145
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    • 2013
  • The recycling of coal bottom ash generated from coal power plants in Korea has been limited due to heterogenous characteristics of the materials. The most common management option for the ash is disposal in landfills (i.e. ash pond) near ocean. The presence of large coarse and fine materials in the ash has prompted the desire to beneficially use it in an application such as fill materials. Prior to reuse application as fill materials, the potential risks to the environment must be assessed with regard to the impacts. In this study, a total of nine test cells with bottom ash samples collected from pretreated bottom ash piles and coal ash pond in a coal-fired power plant were constructed and operated under the field conditions to evaluate the leachability over a period of 210 days. Leachate samples from the test cells were analyzed for a number of chemical parameters (e.g., pH, salinity, electrical conductance, anions, and metals). The concentrations of chemicals detected in the leachate were compared to appropriate standards (drinking water standard) with dilution attenuation factor, if possible, to assess potential leaching risks to the surrounding area. Based on the leachate analysis, most of the samples showed slightly high pH values for the coal ash contained test cells, and contained several ions such as sodium, potassium, calcium, magnesium, chloride, sulfate, and nitrate in relatively large quantities. Three elements (aluminum, boron, and barium) were commonly detected above their respective detection limits in a number of leachate samples, especially in the early leaching period of time. The results of the test cell study indicate that the pollutants in the leachate from the coal ash test cells were not of a major concern in terms of leaching risk to surface water and groundwater under field conditions as fill materials. However, care must be taken in extending these results to actual applications because the results presented in this study are based on the limited field test settings and time frame. Structural characteristics and analysis for coal bottom ash may be warranted to apply the materials to actual field conditions.