research on direct measurement of time series and spatial distribution of reactor noises for criticality safety

反应堆噪声信号长期以来被用来表征反应堆和/或临界组件中的中子场参数。确定噪声信号时间相关性的方法有很多，如Feynman-alpha法、Rossi-alpha法等，这些方法都是用模块式硬件实现的，如多通道定标器（MCS）、时间分析器、快速傅立叶变换器等，并有特殊的解析公式。实现了探测器信号到达时间的直接阅读，并尝试了进一步的应用。实际上，反应堆噪声的信息包括在来自所用探测器的信号的时间序列中，并且它们的直接测量应提供所有所需的数据。探测器信号到达时间的直接阅读一般用录音机（ATR）来完成，有时也尝试应用于反应堆噪声测量。虽然ATR方法简单实用，但数据 ...更多信息 处理不是在线的，在μ秒区域中的死区时间特性不清楚，并且通常没有建立增加输入数量的技术。本文介绍了一种用微机实现直接时间序列数据采集的测试系统，并将该系统应用于中子场参数的测量。为了直接读出计算机存储器地址中信号的到达时间，在微机接口中设置了一个由门电路、时钟电路和寄存器电路组成的控制电路，经过多次工作，完成了最终设计电路。该电路使用0.5MHz时钟读取每个事件信号，并附上到达时间。在kHz计数条件下，它具有约1 μ s的死区时间性能。输入的数量增加到四个，然后几个互相关测量成为可能。该系统已在九州大学的次临界组件、近畿大学反应堆和动力反应堆和核燃料开发公司的临界组件（DCA）进行了多次测试。最后，实现了直接时间序列数据采集技术，并从一个探测器的时间序列数据中在线获得了Feynman-alpha、Rossi-alpha和功率谱分析数据，建立了无需特殊硬件的中子场信号直接时间序列测量的概念。少

The reactor noise signal is long used to characterize neutron field parameters in reactors and/or critical assemblys. There are many procedures to determine the time correlation of noise signals, as methods of Feynman-alpha, Rossi-alpha power spectrum and so on. These procedures are rearized with some module-type hardwares, for example, multi-channel scaler (MCS), so-called time analyzers, fast Fourier transformers, with special analytical formula.In the present work, direct reading of the arriving time of detector signals is realized and further applications are tried. Intrinsically, the information of the reactor noise is included in the time-series of the signal from the used detector and their direct measurement should provide all the required data. Direct reading of the arriving time of detector signal has been performed generally by audio tape recorder (ATR) and applications to reactor noise measurements are sometimes tried. Although the ATR method is simmple and useful, the data … More treatment is not of on-line, the dead-time characteristics is not clear in mu second region and technique of increasing the number of input is not established in general. Especially, recent requirement is possibility of fast on-line data accuisition.Authors have developed a test system to realize the direct time-series data accusition with a microcomputer and the designed system has been appllied to measure neutron field parameters. To read directly the arriving time of the signal in a memory address of a computer, a control circuit is installed in the interface of a micro-computer, which consists of gate, clock and registration circuits.After several works, a finaly designed circuit is completed. This circuit reads each event signal with attaching the arriving time using a 0.5MHz clock. It has dead-time performance of about 1mus under kHz counting condition. The number of input is increased to four and then several cross-correlation measurement become possible. This system has been tested several times at the sub-critical assembly of Kyushu University, the Kinki University Reacter and the critical assembly(DCA) of Power Reactor and Nuclear Fuel Development Corporation. Finaly, technique of the direct time-series data accuisition is accomplished, and on-line data of Feynman-alpha, Rossi-alpha, and power spectrum analyses are obtained from one time-series data from a detector and the concept of direct time-series measurement of signal from a neutron field without any special hardware is established. Less