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根据非线性动力学理论建立的反应堆噪声分析在功率振荡研究中的应用 总被引:1,自引:0,他引:1
数集是可以用于测定非线性系统时间展开渐近线运动的最简单参数之一。本文提出了该参数在反应堆噪声分析中的应用,并验证了在反应堆功率振荡分析中应用的可能性。该方法的数集等于与一种直观物理变量的振荡模型无关的数值。分析利用了来自计算机实验和通过实际物理系统的实验得到的时间系列数据。对于反应堆功率振荡的详细分析。该方法是可用的。 相似文献
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核反应堆结构中板和壳之间存在较多的接触问题.正确模拟接触物体间的刚度特性是建立反应堆动力分析模型的关键.本研究采用数值计算的方法,通过与试验数据比较,合理地选取接触算法和接触参数,研究核反应堆结构间接触物体的非线性刚度,完善数值计算方法.研究结果证明:采用增广拉格朗日(Lagrange)乘子法和平面应力模型分析板和壳之间的接触刚度能够较好地反映试验结果. 相似文献
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建立三维非线性有限元模型,对反应堆结构进行抗冲击动力响应分析,克服了结构的间隙、接触、摩擦、阻尼、预紧、碰撞、流固耦合、连接刚度等非线性因素;对于吊篮与压力容器间的流固耦合作用,建立水动力质量矩阵,并采用ANSYS声单元验证其准确性;设置了三维的堆芯上下板,并建立了多组燃料组件模型,考虑其预紧、跳起、与围板的间隙及碰撞,并考虑水平与竖直方向的耦合,更加精确地模拟了反应堆结构动力响应;以3个方向的冲击加速度时程作为计算输入,得到了各部件的响应,为各部件应力分析及控制棒驱动线抗冲击试验提供输入。该方法为反应堆结构的三维动力响应分析提供借鉴。 相似文献
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文章通过采用PSA技术对不同的低温超压保护的仪控实现方案进行分析对比,在综合考虑系统可靠性和经济性之后,选出合适的仪控实现方案,并结合反应堆保护系统的设计经验,探索PSA技术对提高反应堆保护系统设计质量的可行措施和建议。 相似文献
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《Journal of Nuclear Science and Technology》2013,50(4):227-233
The reactor noise analysis technique is particularly useful in reactor diagnosis for on-line monitoring if the raw noise signals can be processed in almost real time. An on-line reactor noise analysis system has been developed with use made of the mini-computer HITAC-10. This system utilizes functions for calculating the power spectral density in almost real time, plots the output by digital incremental plotter, and displays the results by means of color graphic display equipment, in order to detect anomalous reactor conditions with the statistical technique. Using this system, reactor noise signals have been measured and analyzed under various operational conditions in the JMTR. The variance of the power spectral density is found to fit a logarithmic probability density function. This function is independent of the frequency, but is dependent on the number of sampling functions. A logical procedure for anomaly detection based on statistical characteristics has been developed. It is applied to a case where it is supposed that the PWR operating mode in the OWL-1 is the normal process and that the BWR mode is the anomalous. It is demonstrated as a result, that this procedure can successfully detect anomalous processes. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(10):710-719
A method is proposed for conducting power reactor noise analysis without recourse to an actual high power reactor. The basic concept is to simulate the power reactor noise by integrating the different elements constituting the actual reactor noise, such as the random noise-generating force, the zero-power reactor transfer function, and feed- back loops between the reactor power and the noise-generating force. For the simulation study, a nucleate boiling noise generator and a single feed-back loop were divised to permit experiments with flux-related heater input using the fast neutron source reactor YAYOI of the University of Tokyo. This report discusses problems encountered in applying the proposed method to the simulation of power reactor noise, and presents some of the results obtained: Two kinds of change in amplitude were observed in the normalized auto power spectral density of the neutron flux, emanating form: (a) fluctuating displacements of the boiling zone bottom boundary, and (b) fluctuating number of passing vapor voids. Significant differences in the resulting data were observed between the runs performed with constant and with flux-related heater input in the case of step response experiment, but not in steady noise analyses. This apparent ineffectiveness of the feed-back system is due to the relatively small value of the product of the reactivity power coefficient and the reactor power (–5×10-2%Δk/k) in the present feed-back experiment. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(5):351-358
Empirical studies of coherences between measurement variables from the operating data of a commercial nuclear power station of 460 MWe are applied to derive dynamical characteristics of the Boiling Water Reactor and to attempt to identify the noise sources of the neutron flux. Multivariate techniques with the partial coherence function and the multiple coherence function are introduced to eliminate correlated effects among measurement variables due to thermal hydraulic coupling and sophisticated reactivity feedbacks. From the results, the usual coherency (the ordinary coherence function) may not be adequate to estimate linear relations between measurement variables of the BWR. Furthermore, the noise sources of the neutron flux is discussed. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(4):225-234
A reactor noise monitor has been developed to provide a tool that serves the real time routine function of detecting anomalous states of operation in power reactors. In this monitor, RMS (root mean square) values and average frequencies of noise signals are calculated on a real time basis. The average frequency is defined as the frequency averaged by weighting with PSD (power spectral density) of the noise signal and proved to be equivalent to the ratio of an RMS value of the differentiated noise signal to an RMS value of the noise signal itself. Thus, the average frequency can be obtained on a real time basis by using a differentiator, an RMS calculator and a divider. The frequency components of 12 kinds of signals ranging of 0.01–36 Hz are divided into two or three frequency regions by band-pass filters and the RMS value and the average frequency of each frequency region are obtained by the digital calculation method. The performance of this monitor was tested by using a simulated anomalous signal with a peak on its PSD. From the test, it is proved that this monitor can detect more than changes of the RMS value and average frequency. The functions of this monitor were also confirmed at the actual BWR power plant. In addition, a method to detect peak location of PSD is developed and the accuracy of the peak frequency measurement of the proposed method is investigated to be satisfactory. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(4):161-171
Irreversible circulation of fluctuation, α , is introduced as a new variable for the analysis of reactor noise in the normal case, which further develops our previous formulation based on the system size expansion method. It is shown that α—considered in conjunction with the variance σ—provides useful information about reactor noise, apart from the data we usually obtain on power spectral density. The relations holding between α and the conventionally used variables are given for the case of steady state. The present formalism is applied to a non-linear system with three degrees of freedom (total neutron number, fuel energy and coolant energy), to examine numerically the behavior of the fluctuations. The stability is illustrated as a phase diagram in a reactorparameter space. It is shown that the so-called soft-and hard-mode instabilities can be distinguished by observing α It is also demonstrated that appropriate processing of such quantities as α and σ will provide advance information on instabilities in power reactors. 相似文献
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《Journal of Nuclear Science and Technology》2013,50(9):677-686
In the Halden Boiling Water Reactor (HBWR), a resonant power oscillation with a period around 0.04 Hz is observed at power levels higher than about 9.5 MWt. Although this resonant oscillation is not so strong as to affect the normal reactor operation, it is significant, from the viewpoint of reactor diagnosis, to reveal the cause of this oscillation as well as to understand its characteristics. Noise analysis based on the autoregressive (AR) modeling technique together with spectral and correlation analyses is performed to investigate the driving source, which indicates that it is attributed to the dynamic interference with the reactor of heat exchange process in two parallel-connected steam transformers. The present study demonstrates the effectiveness of the technique applied here for determining the so-called noise source inducing variations of quantities in a system together with its applicability to various problems in the field of reactor noise analysis and diagnosis. 相似文献