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Establishing a Relationship between Coal Quality and the Enrichment of Radionuclides in Coal Combustion Residues 建立煤质与煤燃烧残留物中放射性核素富集的关系
Pub Date : 2019-06-21 DOI: 10.4236/WJNST.2019.93008
U. A. Q. Ahmed, A. Joubert
Coal-fired power plants (CFPP) provide approximately 40% of the world’s energy demand. Naturally occurring radioactive materials (NORM) contained in coal become enriched in coal combustion residues as a result of the elimination of carbon during combustion. The fly ash and bottom ash produced from CFPP may be significant sources of exposure to naturally occurring radionuclides for the population near the combustion plant or ash dumps. Despite this fact, very few studies have actually addressed the relationship of the NORM enrichment factors and the quality of coal used. This paper aims to relate the quality of coal to the enrichment factors for the radionuclides of interest (K40, Ra226, Th232 and Po210) in coal combustion residues from three South African CFPP. The data from other CFPP was also taken into account to establish this correlation. The feedstock coal used in these CFPP is typically low quality, with ash content in the range of 25 - 45 wt%. The radionuclides investigated were determined by gamma spectrometry with the exception of Po210, which was determined by alpha spectrometry. The enrichment factors for the radionuclides of K40, Ra226, Th232 and Po210 in the fly ash and bottom ash (except Po210) was found to be directly proportional to the quality of coal. That is when the ash percentage increased (coal quality decreased) the enrichment factor decreased. The Po210 radionuclide in the bottom ash had an enrichment factor less than one. The relationship between coal quality and enrichment factors for the radionuclides of K40, Ra226, Th232 and Po210 in both the fly ash and bottom ash (except Po210 in the bottom ash) was demonstrated by the following mathematical equation: . This equation may be used as a good indication in obtaining an estimate in determining the enrichment of the mentioned radionuclides in coal combustion products such as fly ash and bottom ash.
燃煤发电厂(CFPP)提供了全球约40%的能源需求。煤中含有的天然放射性物质(NORM)由于在燃烧过程中消除了碳而在煤燃烧残留物中富集。CFPP产生的飞灰和底灰可能是燃烧厂或灰场附近人群接触天然放射性核素的重要来源。尽管如此,很少有研究真正涉及NORM富集因子与所用煤炭质量之间的关系。本文旨在将煤的质量与南非三个CFPP煤燃烧残留物中感兴趣的放射性核素(K40、Ra226、Th232和Po210)的富集因子联系起来。还考虑了其他CFPP的数据来建立这种相关性。这些CFPP中使用的原料煤通常质量较低,灰分含量在25-45wt%范围内。所研究的放射性核素通过伽马能谱法测定,但Po210除外,它是通过α能谱法确定的。飞灰和底灰(Po210除外)中K40、Ra226、Th232和Po210放射性核素的富集因子与煤质成正比。也就是说,当灰分百分比增加(煤质降低)时,富集系数降低。底灰中的Po210放射性核素的富集系数小于1。粉煤灰和底灰中K40、Ra226、Th232和Po210放射性核素(除底灰中的Po210外)的煤质与富集因子之间的关系由以下数学方程证明:。该方程可以用作在确定煤燃烧产物(如飞灰和底灰)中所述放射性核素的富集度时获得估计值的良好指示。
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引用次数: 1
Atom’s Nuclear Structure and the Periodic Table of the Chemical Elements 原子的核结构和化学元素周期表
Pub Date : 2019-06-21 DOI: 10.4236/WJNST.2019.93010
F. Menegus
A new method for the identification of the chemical Elements isotopes takes advantage of the isotope Neutron Excess (NE) number. The repre-sentation of the natural isotopes in the Z-NE plane reveals a surprising correspondence between atom’s nuclear and electronic structures. Nuclear directs the atom electronic structure in spite of the alternative set of numbers ruling the two main atom’s compartments. These compartments appear better integrated than actually considered. The Mendeleev periodic table is rooted in the atom’s nuclear structure. Two recent studies arrive to identical conclusions.
一种利用同位素中子过剩(NE)数鉴定化学元素同位素的新方法。天然同位素在Z-NE平面上的表现揭示了原子核结构和电子结构之间惊人的对应关系。核子指导原子的电子结构,尽管支配两个主要原子室的一组替代数字。这些隔间看起来比实际考虑的更一体化。门捷列夫周期表植根于原子的核结构。最近的两项研究得出了相同的结论。
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引用次数: 0
Study of Radionuclides and Radon Exhalation Rate in Soil and Sand Samples from Tiba, Luxor, Governorate 卢克索省Tiba土壤和沙子样品中放射性核素和氡析出率的研究
Pub Date : 2019-04-25 DOI: 10.4236/WJNST.2019.92006
H. Negm, N. K. Ahmed, A. Abbady, Mahasen Reda
In this study, the natural radionuclides in soil and sand have been measured by using high purity germanium (HPGe) detector. While, radon exhalation rate has been measured by Alpha GUARD. The data analysis is performed to determine 226Ra, 232Th, and 40K activity concentrations in addition to 222Rn exhalation rate. The values of radium equivalent activity (Raeq), external hazard index (Hex), internal hazard index (Hin), and absorbed dose rate were ranged from 46.46 to 124.16 Bq⋅kg−1, 0.07 to 0.33 Bq⋅kg−1, 0.09 to 0.42 Bq⋅kg−1, and 13.24 to 58.37 nGy⋅h−1 respectively in all samples. The area and mass exhalation rates were increased from 9.16 ± 2.83 to 16.18 ± 2.83 Bq⋅m−2⋅h−1 and 1.8 ± 1.34 to 11.35 ± 0.98 Bq⋅kg−1⋅h−1 respectively.
本文用高纯锗(HPGe)探测器对土壤和沙土中的天然放射性核素进行了测定。而氡的呼出率则由Alpha GUARD测量。进行数据分析以确定226Ra, 232Th和40K活性浓度以及222Rn呼出率。所有样品的镭当量活度(Raeq)、外危害指数(Hex)、内危害指数(Hin)和吸收剂量率分别为46.46 ~ 124.16 Bq⋅kg - 1、0.07 ~ 0.33 Bq⋅kg - 1、0.09 ~ 0.42 Bq⋅kg - 1和13.24 ~ 58.37 nGy⋅h - 1。面积和质量呼出率分别从9.16±2.83增加到16.18±2.83 Bq⋅m−2⋅h−1和1.8±1.34增加到11.35±0.98 Bq⋅kg−1⋅h−1。
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引用次数: 4
Radiotracers and Nucleonic Control Systems Applied in Industry—Polish Case 放射性示踪剂和核子控制系统在工业中的应用——以波兰为例
Pub Date : 2019-03-07 DOI: 10.4236/WJNST.2019.92003
A. Chmielewski, T. Smolinski, M. Rogowski
Nuclear and radiation technologies play an important role in Polish power sector, oil industry and mining sector, starting from fossil fuels exploitation, their transport and distribution and finally power generation. Application of environmental isotopes, stable and radioactive, in ground water monitoring in the vicinity of open cast lignite mine, and radon monitor applied for miner’s safety in deep coal mines and nucleonic control systems for ash in coal quality control is often used in mining industry. Other applications of nuclear techniques reviewed, concern the oil industry, oil field recovery, transportation pipelines and refineries. Finally, the application of beta radiation-based gauges for air borne fly ash monitoring and radiation technology for flue gas treatment are the examples of using this technique in power sector equipped with coal and oil fired boilers [1]. The radiotracers techniques were used also in glass industry (determination and optimization parameters of the furnaces), cement industry (test of aggregates for the production of cement and optimization media transport in pipelines), metallurgy of Cu, Pb, Zn (investigation of pyrometallurgy processes and new techniques), cellulose industry, environmental and (mainly hydrological) research etc. [2]. The article is brief review of present status of radiotracer and nucleonic gauges techniques as applied to polish industry.
核能和辐射技术在波兰的电力部门、石油工业和采矿业中发挥着重要作用,从化石燃料的开采、运输和分配到最后的发电。稳定和放射性环境同位素在露天褐煤矿区附近地下水监测中的应用,以及在深部煤矿中用于矿工安全的氡监测仪和在煤质控制中用于灰分的核控制系统在矿山工业中的应用。所审查的核技术的其他应用涉及石油工业、油田开采、运输管道和炼油厂。最后,基于β辐射的空气飞灰监测仪表的应用和烟气处理的辐射技术是该技术在配备燃煤和燃油锅炉[1]的电力部门应用的例子。放射性示踪剂技术还用于玻璃工业(炉窑参数的确定和优化)、水泥工业(水泥生产骨料的测试和管道介质输送的优化)、铜、铅、锌冶金(火法冶金工艺和新技术的研究)、纤维素工业、环境和(主要是水文)研究等领域。本文简要介绍了放射性示踪剂和核子计技术在抛光工业中的应用现状。
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引用次数: 1
Natural Radioactivity Measurement and Dose Assessment in Soil Samples from Some Selected Areas of Mali 马里一些选定地区土壤样品的天然放射性测量和剂量评估
Pub Date : 2019-03-06 DOI: 10.4236/WJNST.2019.92004
I. Traore, A. Ba, A. Nourreddine
This is the first time that a study applies the gamma ray spectroscopy using a high purity germanium to evaluate the terrestrial gamma radiation level by detector in selected regions of Mali. The results reveal that the activity concentrations of naturally occurring 226Ra, 232Th and 40K radionuclides ranges between respectively 17.26 ± 1.81 and 105.43 ± 10.36; 20.41 ± 2.52 and 180.85 ± 19.69; 41.33 ± 8.26 and 627.63 ± 85.62 Bq⋅kg−1. The measures of radium equivalent activity (Raeq), absorbed dose rates (ADR), annual effective dose rate (AEDR), external hazard index (Hex), internal hazard index (Hin) and excess lifetime cancer risk (ELCR) were evaluated. Some of the obtained values exceed the recommended safe levels. Further studies are necessary to constitute a baseline reference data about the terrestrial radiation in Mali.
这是首次在马里选定地区应用高纯度锗的伽马射线光谱来评估探测器的地面伽马辐射水平。结果表明,天然存在的226Ra、232Th和40K放射性核素的活度浓度分别在17.26±1.81和105.43±10.36之间;20.41±2.52和180.85±19.69;41.33±8.26和627.63±85.62 Bq·kg−1。评估了镭当量活度(Raeq)、吸收剂量率(ADR)、年有效剂量率(AEDR)、外部危险指数(Hex)、内部危险指数(Hin)和癌症超额寿命风险(ELCR)。获得的某些值超过了建议的安全级别。有必要进行进一步的研究,以构成马里地面辐射的基准参考数据。
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引用次数: 1
New Formulation for Semi-Empirical Correlations for Penetration Jets 侵彻射流半经验关系式的新公式
Pub Date : 2019-03-06 DOI: 10.4236/WJNST.2019.92007
R. Pacheco, L. O. Freire, M. S. Rocha, N. Scuro, M. O. Menezes, D. A. Andrade
Correlations for the extension of a water vapor jet injected in a liquid pool were historically proposed considering the mass flux (kg/m2/s) as a constant. The results were satisfactory, however adjusting the values by linear regression. Although, it presents the following drawbacks: 1) the formulation is only valid for the specific range of data for what it was created; 2) it does not allow the analytical evaluation of the heat transfer coefficient from the extension equation. This paper proposes a new formulation for the calculation of the mass flux, in such a way to remove both of these drawbacks.
历史上曾提出将质量通量(kg/m2/s)作为常数来考虑注入液体池中的水蒸气射流扩展的相关关系。结果令人满意,但通过线性回归调整了数值。虽然,它提出了以下缺点:1)公式只适用于特定范围的数据为它所创建的;2)它不允许从扩展方程解析计算换热系数。本文提出了一种计算质量通量的新公式,从而消除了这两个缺点。
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引用次数: 0
Analysis of Neutronics and Thermal-Hydraulic Behavior in a Fuel Pin of Pressurized Water Reactor (PWR) 压水堆燃料销钉的中子学和热工水力学特性分析
Pub Date : 2019-03-06 DOI: 10.4236/WJNST.2019.92005
M. Zakir, M. Sarkar, A. Hossain
This paper presents a comparative analysis of different parameters such as enthalpy, moderator temperature, moderator density, flow velocity, pressure, and fuel temperature profile at the fuel pin cell level of PWR. Moreover, in this paper pitches to fuel pin radius ratio are varied from 2.3 to 4. The methods and implementation strategy are such that the coupled neutronic and thermal-hydraulic analysis is executed in a fully one dimensional (1D) manner. The thermal hydraulic is based on moderator/coolant mass and enthalpy equation together with one group diffusion equation for fuel pin. Modelling of fuel pin cell and subchannel is executed in two steps. First, the governing equations are derived assuming that all the parameters appearing in the equations are temperature independent. Fuel pin centerline temperature and radially averaged temperature equations are derived from Fourier laws of thermal conductivity. Finally, diffusion coefficient, fission cross-section and absorbing cross-section are evaluated with respect to the fuel pin temperature. The outcome will be helpful for further neutronics and thermal analysis of PWR. Thermal hydraulics parameter varies the maximum 30 percentage from the lowermost value.
本文对压水堆燃料针电池级的焓、慢化剂温度、慢化剂密度、流速、压力和燃料温度分布等不同参数进行了比较分析。此外,在本文中,节距与燃料销的半径比在2.3到4之间变化。所述方法和实施策略使得以完全一维(1D)方式执行耦合的中子和热工水力学分析。热工水力学是基于慢化剂/冷却剂的质量和焓方程以及燃料棒的一组扩散方程。燃料针式电池和子通道的建模分两步进行。首先,假设方程中出现的所有参数都与温度无关,推导出控制方程。根据导热系数的傅立叶定律,导出了燃料销中心线温度和径向平均温度方程。最后,根据燃料棒温度对扩散系数、裂变截面和吸收截面进行了评估。这一结果将有助于PWR的中子学和热分析。热工水力学参数与最低值相差最大30%。
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引用次数: 7
Application of a Mathematical Model to the Sierra Indiana Ore Leaching Process Containing Thorium, by Means of H2SO4 Solution and HCl 数学模型在Sierra Indiana含钍矿石H2SO4溶液和HCl浸出过程中的应用
Pub Date : 2019-01-15 DOI: 10.4236/wjnst.2019.91002
Pedro Orrego, P. Fleming, J. Skeet, Ramón Ávila
The existence of the thorium element in the ores from the Atacama region, Chile, and its importance in the activities of the nuclear industry, have generated the interest of the Chilean Nuclear Energy Commission (CChEN) to study the technical feasibility of its recovery, like ThO2 through the implementation of hydrometallurgical techniques, such as leaching, solvent extraction, among others. The present work has become a report about the research carried out in the Extractive Metallurgy Area of the Department of Advanced Materials of CChEN, whose objective is to know the behavior of the thorium element when the mineral carrier is leached. The leaching tests were carried out in a glass reactor in batch mode, by mechanical agitation, varying different operational parameters, such as: type of leaching solution, concentration of acid in the solution, system temperature and granulometry of the mineral. The results indicate that there is technical feasibility for the recovery of thorium by leaching the mineral carrier with hydrochloric and/or sulfuric solution. The highest recovery of thorium for a sulfuric solution was 70.0% and for a hydrochloric solution of 83.8%, so the process presents a good efficiency in both cases. For a hydrochloric solution, the mathematical model of the thorium recovery efficiency obtained is: Y=31.14+26.25*X1+8.69*X2−0.82*X3+9.5*X12−0.83*X13−3.71*X23−1.83*X123+6.45 The concentration of HCl and temperature, as well as their interaction, significantly affect the recovery of thorium for Sierra Indiana mineral, as well as temperature and granulometry. The previous model gives a good representativeness of 99.98%. For a sulfuric solution, the mathematical model of the thorium recovery efficiency obtained is: Y=29.78+25.92*X1+0.99*X2−1.05*X3−2.05*X12−9.84*X13−5.26*X23−3.87*X123+15.18 The model indicates that the recovery of thorium for the mineral is significantly affected by the concentration of sulfuric acid, and to a lesser degree by the temperature and granulometry. The model provides a representativeness of 98.3%.
智利阿塔卡马地区矿石中钍元素的存在及其在核工业活动中的重要性,引起了智利核能委员会(CChEN)的兴趣,研究其回收的技术可行性,如通过实施湿法冶金技术,如浸出、溶剂萃取等。本工作已成为陈晨先进材料部萃取冶金领域的研究报告,其目的是了解矿物载体浸出时钍元素的行为。浸出试验在玻璃反应器中分批进行,通过机械搅拌,改变不同的操作参数,如:浸出溶液的类型,溶液中的酸浓度,系统温度和矿物的粒度。结果表明,用盐酸或硫酸溶液浸出矿物载体回收钍在技术上是可行的。硫酸溶液中钍的最高回收率为70.0%,盐酸溶液中钍的最高回收率为83.8%,因此该工艺在两种情况下都具有良好的效率。在盐酸溶液中,得到的钍回收率数学模型为:Y=31.14+26.25*X1+8.69*X2 - 0.82*X3+9.5*X12 - 0.83*X13 - 3.71*X23 - 1.83*X123+6.45。HCl浓度、温度、粒度等因素对Sierra Indiana矿物中钍的回收率有显著影响。之前的模型给出了99.98%的良好代表性。对于硫酸溶液,得到的钍回收率的数学模型为:Y=29.78+25.92*X1+0.99*X2 - 1.05*X3 - 2.05*X12 - 9.84*X13 - 5.26*X23 - 3.87*X123+15.18。该模型表明,硫酸浓度对矿物钍的回收率有显著影响,温度和粒度对钍回收率的影响较小。该模型的代表性为98.3%。
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引用次数: 0
Development of ToSPACE for Pipe Wall Thinning Management in Nuclear Power Plants ToSPACE在核电厂管壁减薄管理中的开发
Pub Date : 2019-01-01 DOI: 10.4236/wjnst.2019.91001
K. Hwang, Hun Yun, Hyeok Seo, G. Lee, Kyung Woo Kim
A number of piping components in the secondary system of nuclear power plants are exposed to aging mechanisms such as FAC (Flow-Accelerated Corrosion), cavitation, flashing, SPE (Solid Particle Erosion), LDIE (Liquid Droplet Impingement Erosion), etc. Those mechanisms may lead to thinning, leak, or rupture of the components. Due to the pipe ruptures caused by wall thinning in Surry unit 2 of USA in 1986 and in Mihama unit 3 of Japan in 1994, the pipe wall thinning management has emerged as one of the most important issues in nuclear power plants. To manage the pipe wall thinning in the secondary system, Korea has used a foreign program since 1996. As using the foreign country’s program for long term, it was necessary to improve from the perspective of the users. Accordingly, KEPCO-E & C has started to develop the 3D-based pipe wall thinning management program (ToSPACE, Total Solution for Piping And Component Engineering management) from eight years ago, and the development was successful. This paper describes the major functions included in ToSPACE program, such as 3D-based DB (Database) buildup, development of FAC and erosion evaluation theories, UT (Ultra-sonic Test) data reliability analysis, field connection with 3D, automatic establishment of long-term inspection plan, etc. ToSPACE program was developed to allow site engineers performing the selection of inspection quantity at each refueling outage, UT data reliability analysis, UT evaluation, determination of next inspection timing, identification of the inspecting and replacing components in 3D drawings, etc., to access easily.
核电站二次系统中的许多管道部件都面临着FAC(流动加速腐蚀)、空化、闪蒸、SPE(固体颗粒侵蚀)、LDIE(液滴撞击侵蚀)等老化机制。这些机制可能导致部件变薄、泄漏或破裂。由于1986年美国萨里2号机组和1994年日本三滨3号机组的管壁变薄导致的管道破裂,管壁变薄管理成为核电站最重要的问题之一。从1996年开始,为了管理二级系统的管壁变薄问题,韩国采用了国外的方案。由于长期使用国外程序,需要从用户的角度进行改进。因此,kepco - e&c从8年前开始开发基于3d的管壁减薄管理程序(ToSPACE,管道和部件工程管理总解决方案),并取得了成功。本文介绍了ToSPACE项目所包含的主要功能,如基于3D的DB(数据库)建立、FAC和侵蚀评估理论的发展、UT(超声波测试)数据可靠性分析、与3D的现场连接、自动建立长期检测计划等。开发ToSPACE程序是为了方便现场工程师在每次换料停机时选择检查数量、UT数据可靠性分析、UT评估、确定下一次检查时间、识别3D图纸中的检查和更换部件等。
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引用次数: 6
A Way to Realize Controlled Nuclear Fusion by γ-Laser or γ-Ray 一种利用γ激光或γ射线实现可控核聚变的方法
Pub Date : 2018-10-24 DOI: 10.4236/WJNST.2018.84016
Shihao Chen, Ziwei Chen
A way is proposed to realize controllable-nuclear fusion by γ-laser or γ-ray and ordinary laser with their certain frequencies and large enough intensities to irradiate a target ball. The function of ordinary laser is to heat the target nuclei and to realize the inertial confinement for the target nuclei. The target nuclei absorbing γ-photons will be in a certain excited state. The scattering cross-sections will be larger and the ignition temperature will be lower to realize fusion of the nuclei in their excited states than those of the nuclei in their ground states. In contrast with the nuclei applied in conventional fusion, e.g., deutons and tritons, according to the way, the nuclei applied to fusion should have the following characters: the nuclei have their excited states, one of the excited states has higher energy and longer lifetime, and the masses of the nuclei are lesser. Thus, the Lawson conditions can more easily be realized so that the controllable nuclear fusion is possibly realized by the way.
提出了一种利用γ激光或γ射线与普通激光实现可控核聚变的方法,这些激光具有一定的频率和足够大的强度来照射目标球。普通激光的作用是加热靶核,实现对靶核的惯性约束。吸收γ光子的靶核将处于一定的激发态。散射截面将更大,点火温度将更低,以实现处于激发态的原子核比处于基态的原子核的聚变。与传统聚变中应用的原子核,如双原子核和三原子核相比,根据方法,应用于聚变的原子核应具有以下特征:原子核有其激发态,其中一个激发态具有更高的能量和更长的寿命,原子核的质量更小。因此,可以更容易地实现劳森条件,从而有可能实现可控核聚变。
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引用次数: 2
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核科学与技术国际期刊(英文)
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