The Effect of Neutron Source Distribution on Subcriticality Measurement of Pressurized Water Reactors Using the Modified Neutron Source Multiplication Method
The Effect of Neutron Source Distribution on Subcriticality Measurement of Pressurized Water Reactors Using the Modified Neutron Source Multiplication Method
复制标题
中子源分布对采用改进中子源倍增法测量压水堆亚临界度的影响
DOI：
10.1080/18811248.2003.9715438
复制
发表时间：
2003
影响因子：
1.2
通讯作者：
Y. Shimazu
中科院分区：
文献类型：
--
作者：
W. Naing;Masashi Tsuji;Y. Shimazu
研究了一种改进的中子源倍增法在压水堆次临界测量中的应用。这种方法是基于从测量的中子信号和空间效应的校正的基本模式的提取。在商业反应堆中，预计主要有两种类型的中子源，一种来自燃烧燃料，另一种来自堆芯固定中子源。为了计算提取因子和空间校正因子，采用有限差分法（FDM）求解固定源问题，以显式处理中子源的空间强度。进行了灵敏度分析，以探讨如何估计的准确性次临界依赖于近似水平的中子源分布。结果发现，这两种中子源都应考虑在内。对于针棒型堆芯固定中子源，局部源强度在相关节点的径向上平均的节点分布是适用的，因为它可以以与刚性空间处理的情况几乎相同的精度估计次临界。这确保了节点计算可以用于校正因子的评估，而不是繁琐的FDM计算。
A modified neutron source multiplication method has been investigated for application to subcriticality measurement in commercial Pressurized Water Reactors (PWRs). This method is based on the extraction of the fundamental mode from measured neutron signals and corrections for spatial effects. In commercial reactors, mainly two types of neutron sources are expected, one from burnt fuels and the other from in-core fixed neutron sources. To calculate the extraction and spatial correction factors, the fixed source problem was solved by the Finite Difference Method (FDM) to explicitly deal with spatial intensities of neutron sources. Sensitivity analysis was carried out to investigate how the accuracy of estimated subcriticality depends on approximation levels of neutron source distributions. It was found that both of the neutron sources should be taken into account. For a pin rod type of the in-core fixed neutron source, a node-wise distribution for which the localized source intensity is averaged over the radial direction in the relevant nodes is applicable, since it can estimate the subcriticality with almost the same accuracy as in the case with a rigid spatial treatment. This ensures that nodal calculations can be used in the evaluation of correction factors instead of burdensome FDM calculations.