共查询到15条相似文献,搜索用时 46 毫秒
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共振参数计算是反应堆堆芯设计计算中的重要内容,传统的共振计算模型只适应于简单几何计算。本工作应用A.Hebert提出的子群共振自屏计算模型研制了复杂几何燃料组件的共振自屏计算程序。该程序能处理含有两种共振核素的复杂几何下的共振自屏。对一系列问题的数值校验计算表明,该模型在低富集度时具有较好的计算精度。 相似文献
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中子通量探测丝的自屏因子计算李兆桓(中国原子能科学研究院)关键词自屏因子,探测丝,中子散射影响在许多情况下,热中子反应堆内的中子通量是采用丝状探测器测量的。这类探测器的自屏大,不易处理。本文采用一种方法,既考虑中子散射的影响,又能获得较满意的结果。现... 相似文献
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共振自屏效应的处理是影响压水堆组件程序反应性精度的主要因素之一,压水堆锆包壳材料同样具有共振自屏效应,忽略其影响会对反应性造成100~300 pcm(1 pcm=10-5)的偏差。目前,主要通过提供经验上的参考稀释截面与包壳等价理论处理包壳材料的共振自屏效应,但并未对其适用性及精度进行完整的分析。因此,本文采用DRAGON程序,通过一系列压水堆算例对这2种方法进行测试,确定包壳共振自屏效应的主要影响因素以及这2种方法的适用性。结果表明,包壳材料的共振自屏效应仅仅与包壳区的原子核密度、厚度、慢化区的水铀比有关,并且参考稀释截面方法可以满足大部分典型压水堆系统的计算精度,但是对于包壳区尺寸、原子核密度、慢化区水铀比变化较大的系统计算精度较差,而包壳等价理论计算精度和普适性强,可用于不同类型压水堆系统包壳材料的共振自屏计算。 相似文献
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LI Song ZHANG Qian ZHANG Zhijian ZHAO Qiang LIANG Liang LIANG Yuechao ZHANG Jinchao LOU Lei LI Mancang 《原子能科学技术》1959,54(10):1892-1899
The improved subgroup method coupled with Sanchez-Pomraning method (ISSP) was proposed for the resonance self-shielding calculation of double heterogeneity (DH) problems. ISSP employed a fine-mesh energy structure to avoid the extra resonance interference treatment. The DH subgroup fixed source equations and the neutron slowing-down equations were established to obtain the effective resonance cross-section in particle and matrix. Finally, the transport calculation under DH condition was carried out. By contrast with the continuous-energy Monte Carlo method and the ultra-fine group method, numerical verification results indicate that ISSP could provide resonance cross-section in DH condition accurately and effectively. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(2):68-72
The neutron self-shielding factor of 59Co resonance foil as an example of foils whose scattering cross section predominate over their absorption cross sections was obtained by both Monte Carlo method (analog) and the collision probability method for various thicknesses of the foil. Also, the transmission and reflection probabilities of neutrons which have various energies near the resonance energy were obtained, and the effects of multiple scattering of neutrons on the neutron self-shielding factor are discussed. The neutron self-shielding factors obtained by the Monte Carlo method and by the collision probability method agreed well with each other in the cases Σ t ~ 4.0, in which the Monte Carlo method requires considerably longer machine time. Although for the cases of large Σ t (~4.0) the agreement is not always good because of the flat flux approximation in the collision probability method, the calculation time by Monte Carlo is conveniently short. A combination of both methods is useful in obtaining the neutron self-shielding factor of resonance foils. 相似文献