共查询到17条相似文献,搜索用时 46 毫秒
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ARCON96模型是NRC推荐用于核电站主控室可居留性评价的大气弥散因子计算模型。相比于以往的模型,ARCON96模型根据场地实验修正了近距离和静风条件下的扩散参数,使其估计结果更符合实际。本工作研究了ARCON96模型在大气弥散因子估计中的计算行为,并与经典高斯模型进行了比较。随着距离的增加,ARCON96模型估计的大气弥散因子与风速的函数关系逐渐由钟形曲线过渡到近似高斯模型的曲线。同时,随着距离的增加,大气弥散因子最大值所对应的气象条件也逐渐由非静风转变为静风。在各个距离下,ARCON96模型所估算大气弥散因子均小于高斯模型。 相似文献
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本文通过对涉及排放条件、气象条件、下势面条件以及污染物性质等方面的有关参数和修正方法进行充分的分析,确定有关参数和修正方法对年均大气弥散因子的影响范围和程度。结果表明,各个模式参数和修正方法的影响程度和范围各不相同,其中混合释放方式和风随高度的变化等因素很显著,其他一些因素如复杂地形、扩散参数、稳定度分类方法、热内边界层等的影响基本上在2~3倍之内。而通常人们比较关注的因素(如扩散参数、气象资料获取率等)的影响并不显著,从工程项目环境影响分析与评价的角度来看,应合理制定或适当简化这方面的评价程序。 相似文献
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为明确小型堆非居住区和规划限制区的计算方法,选择合适的计算模型,减少审评过程中存在的问题,本研究首先介绍了小型堆的定义,并比较了我国和国际上对小型堆定义的差别。同时说明了我国对小型堆非居住区和规划限制区设置的剂量准则和计算要求。并基于美国NRC发布的RG4.28草案,对比分析了其推荐的现实模型ARCON96与保守模型PAVAN之间的差别。ARCON96模型相比于PAVAN模型能够很好地考虑静风和尾流的影响,更真实地模拟了设施近距离的扩散情景,可有效的缩小非居住区和规划限制区的范围,进而提升小型堆的经济性。 相似文献
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本文探讨了在获取气象数据三维联合频率时,使用美国核管会导则RG 1.23中提供的大气稳定度划分方法,即包括G类极端稳定度,对PAVAN程序计算静风频率较高、平均风速较小的内陆厂址大气弥散因子的影响。分析表明,与采用HAD 101/02根据温度梯度和风速确定的大气稳定度的方法获取的计算输入相比,该方法处理计算输入,得到的大气弥散因子约减小了1/2。由于RG 1.23大气稳定度划分方法对于稳定类天气的划分更加精细,在利用PAVAN软件计算时,可充分考虑到小风情况下的风摆效应,得到适当保守且较为适用于内陆厂址条件的大气弥散因子。 相似文献
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陈昌友 《核工程研究与设计》1996,(18):39-45
关于γ浸没外照射短期大气弥散因子,以前通常使用半无限体源作近似计算,由于高源近距离的计算不合适,故本文对新的计算模式在烟羽轴线上给出它的计算方法。 相似文献
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Xinpeng Li Hong Li Wei Xiong Dong Fang 《Journal of Nuclear Science and Technology》2013,50(11):1263-1274
The radiological habitability of a control room is important for nuclear emergency response, which is also a licensing prerequisite for nuclear power plants. It is determined by both atmospheric relative concentrations and doses received via different pathways. However, most recent studies have focused only on the former, which may not be adequate. The present study therefore investigates the radiological habitability and its sensitivity to different parameters in the high-temperature gas-cooled reactor pebble-bed module power plant. For three typical accidents, the study estimates the body, thyroid and skin doses received via different pathways using the Nuclear Regulatory Commission recommended ARCON96 and dose calculation method in RG 1.195. To make a realistic evaluation, the latest design and site-specific information, including the unique accidental source term, are collected and used as input parameters. The evaluation results reveal that the total dose of different pathways in the control room is far below the limit, which demonstrates the effectiveness of the current design. The inhalation exposure is the dominant pathway, and iodine and caesium are the primary contributors of the inhalation dose. The particle filter removal fraction is the most influential parameter in an accident which the activities of metal radionuclides are high. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(5):744-750
The neutron capture cross section of 96Zr at incident neutron energies from 15 to 100 keV has been measured by the time-of-flight method. Capture γ-rays were detected with an anti-Compton NaI(Tl) spectrometer, and the pulse-height weighting technique was applied to derive the neutron capture cross section. The present measurement provided the capture cross section as a function of incident neutron energy in the keV region. The results were compared with previous measurements and cross section data in the evaluated nuclear data libraries, JENDL-4.0, JENDL-3.3, ENDF/B-VII.0, and ENDF/B-VI.8. The present results revealed considerable underestimation of the evaluated cross sections in the high-energy region of 35–100 keV. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(8):786-793
A steady-state diffusion model has been used widely to determine the diffusivities of radionuclides in rocks. Buffer container at the source solution side is used to keep the concentration constant. It is suitable for non-sorptive species, but not for sorptive species. Some researchers proposed a unsteady-state diffusion model recently. It is possible to use simple experimental apparatus without buffer container to measure the diffusivity with this model. To obtain the diffusional information more easily according to the sorption properties of radionuclides, through- diffusion experiments were performed in granites. Methods of determining of diffusivities are discussed according to sorption properties of species. For the non-sorptive species, the steady- state diffusion model was effective to determine the diffusivity. For the sorptive species, the analytical solution of the unsteady-state diffusion model found to be more appropriate to determine the diffusivity. Surface diffusion of sorbed species on rock did important role in diffusive transport. 相似文献
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《核技术(英文版)》2016,(4):118-130
The data for neutron-induced reactions are indispensable in a lot of applications of nuclear science and technologies. All reaction cross sections, angular distributions, energy spectra, and double-differential cross sections of neutron, proton, deuteron, triton, and alpha-particle emissions are consistently calculated and analyzed for n+~(23)Na reactions at incident neutron energies below200 Me V, based on nuclear theoretical models. The calculated results are compared with the experimental data and the evaluated data in the ENDF/B-VII, JENDL-4.0,and JEFF-3.2 libraries. In most cases, the calculated results describe the corresponding experimental data well. At the resonance energy region, evaluated experimental data are adopted to fit to the resonance structures. 相似文献
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海基核动力装置自然循环数学模型的建立与运行特性研究 总被引:2,自引:2,他引:0
建立了适用于海基核动力装置自然循环运行分析的理论模型,主要包括两相不平衡态、五方程的漂移流模型;改进的混合物动量守恒方程来描述海洋条件引起的附加压降;采用多压力节点模型进行压力矩阵的求解;选择非等温模型计算两相摩擦因子,并考虑摇摆对摩擦因子的影响;对低雷诺数自然循环工况下阻力件的能量损失因子进行了修正;考虑摇摆与浮沉对换热系数的影响;建立了两群三维时空中子动力学模型,采用基于非线性迭代的半解析节块法来求解中子扩散方程.对海基核动力装置在横摇、纵摇、横倾、纵倾、浮沉、直线变速、回转等条件下的自然循环运行特性进行了研究. 相似文献