Subcriticality Measurement of Pressurized Water Reactors by the Modified Neutron Source Multiplication Method
Subcriticality Measurement of Pressurized Water Reactors by the Modified Neutron Source Multiplication Method
复制标题
改进中子源倍增法测量压水堆亚临界状态
DOI：
10.1080/18811248.2003.9715443
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
研究了带基模提取的改进中子源倍增法（NSM）在次临界测量中的适用性。这一概念可应用于商用压水堆定期检查时在反应堆物理试验期间进行的控制棒价值测量。在前期研究的可行性验证的基础上，数值分析，其适用性已被证明在一个更现实的情况下，关于在压水堆启动过程中的控制棒的取出顺序作为一个模拟实验，不同的控制棒插入模式的亚临界估计的基础上修改的NSM方法。即使在未考虑任何用于精确测量的特殊处理的模拟实验中，也可以以良好的精度评估亚临界性，并且可以看到测量信号对反应性变化的不敏感性及其大的波动。确定了一些重要的处理方法，以准确估计：参考亚临界状态必须尽可能接近零。有必要等待足够长的时间，以使缓发中子效应衰减后，反应性变化的控制棒银行撤回。应校正探测器信号中包含的伽马射线污染。
Applicability of the modified Neutron Source Multiplication (NSM) method with extraction of the fundamental mode to subcriticality measurement has been investigated. This concept can be applied to the control rod worth measurement that is performed during reactor physics tests at periodical inspection of commercial PWRs. Following the feasibility verification in the previous study based on numerical analyses, its applicability has been proven in a more realistic situation; Regarding a withdrawal sequence of control rod banks during the PWR startup as a mockup experiment, subcriticalities with various control rod insertion patterns were estimated based on the modified NSM method. The subcriticality could be evaluated with good accuracy even with the mockup experiment where any special treatments for accurate measurement were not taken into account and furthermore the insensitivity of measuring signals by reactivity changes and their large fluctuations were seen. Some vital treatments for accurate estimation were identified: The reference subcritical state must be as closer to zero as possible. It is necessary to wait long enough for the delayed neutron effect to attenuate after a reactivity change by control rod bank withdrawal. Gamma-ray contamination contained in the detector signals should be corrected.