共查询到7条相似文献,搜索用时 0 毫秒
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《等离子体科学和技术》2020,22(1):15601
To satisfy high-precision, wide-range, and real-time neutron flux measurement requirements by the International Thermonuclear Experimental Reactor(ITER), a data acquisition and control system based on fission chamber detectors and fast controller technology, has been developed for neutron flux monitor in ITER Equatorial Port #7. The signal processing units which are based on a field programmable gate array and the PXI Express platform are designed to realize the neutron flux measurement with 1 ms time resolution and a fast response less than 0.2 ms,together with real-time timestamps provided by a timing board. The application of the widerange algorithm allows the system to measure up to 10~(10) cps with a relative error of less than 5%.Furthermore, the system is managed and controlled by a software based on the Experimental Physics and Industrial Control System, compliant with COntrol, Data Access and Communication architecture. 相似文献
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Experiments were performed on a high-speed online random neutron analyzing system(HORNA system)with a 252Cf neutron source(up to 1 GHz sampling rate and 3 input data channel),to obtain time-and frequencydependent signatures which are sensitive to changes in the composition,fissile mass and configuration of the fissile assembly.The data were acquired by three high-speed synchronized acquisition cards at different detector angles,source-detector distances and block sizes.According to the relationship between 252Cf source and the ratio of power spectral density,Rpsd,all the signatures were calculated and analyzed using correlation and periodogram methods.Based on the results,the simulated autocorrelation functions were utilized for identifying different fissile mass with Elman neural network.The experimental results show that the Rpsd almost remains at constant amplitude in frequency range of 0-100 MHz,and is only related to the angle and source-detector distance.The trained Elman neural network is able to distinguish the characteristics of autocorrelation function and identify different fissile mass.The average identification rate reached 90% with high robustness. 相似文献
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Yuji Fukaya 《Journal of Nuclear Science and Technology》2013,50(4):442-448
In this study, an improved method for calculating the effective delayed neutron fraction of a core with a few collapsed energy groups has been developed. To accurately calculate the effective delayed neutron fraction of a core using the conventional method, a structure with several energy groups is needed for the fast energy region in order to reflect the difference in the fission spectra for prompt fission neutrons and delayed neutrons. On the other hand, a structure with only a few energy groups is needed for the criticality evaluation. Thus, the calculation cost increases for the effective delayed neutron fraction calculations owing to the need for a large number of energy groups. To solve this problem, in the present study, the error mechanism for the effective delayed neutron fraction calculation using a structure with only a few energy groups was studied, and it was found that the error results from the collapse of the fission spectra after the cell calculations without adjoint flux weighting. In addition, an improved method for the collapse fission spectra with an adjoint flux obtained by one-point calculation was developed. Using the proposed method, the effective delayed neutron fraction can be estimated with sufficient accuracy using a structure consisting of only a few collapsed energy groups. This result will contribute to reducing the calculation cost and/or improving the accuracy of effective delayed neutron fraction calculations. 相似文献
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Jiaxing XIE 《等离子体科学和技术》2022,24(6):64004
A millimeter wave solid state source—far infrared laser combined interferometer system (MFCI) consisting of a three-channel 890 GHz hydrogen cyanide (HCN) laser interferometer and a three-channel 340 GHz solid state source interferometer (SSI) is developed for real-time line-integrated electron density feedback and electron density profile of the EXL-50 spherical tokamak device. The interferometer system is a Mach–Zehnder type, with all probe-channels measured vertically, covering the plasma magnetic axis to the outermost closed magnetic plane. The HCN laser interferometer uses an HCN laser with a frequency of 890 GHz as a light source and modulates a 100 kHz beat signal by a rotating grating, giving a temporal resolution of 10 μs. The SSI uses two independent 340 GHz solid-state diode sources as the light source, the frequency of the two sources is adjustable, and the temporal resolution of SSI can reach 1 μs by setting the frequency difference of the two lasers at 1 MHz. The main optical path of the two interferometers is compactly installed on a set of double-layer optical platform directly below EXL-50. Dual optical path design using corner cube reflectors avoids the large support structures. Collinear the probe-beams of two wavelengths, then the phase error caused by vibration can be compensated. At present, the phase noise of the HCN Interferometer is 0.08 rad, corresponding to a line-integrated electron density of 0.88 × 1017 m−2, one channel of measuring result was obtained by the MFCI system, and the highest density measured is about 0.7 × 1019 m−2. 相似文献