[en] Pipe thermal fatigue crack phenomena are that caused by thermal stress effect with long time. Pipe thermal fatigue crack accident is lower probability in nuclear power plant, but it should be paid enough attention because the crack accident may lead to lose of coolant accident (LOCA). The paper analyses and classifies the thermal fatigue mechanism. According to different pipe thermal fatigue characters, it makes thermal fatigue prevention suggestions that should be adopted in nuclear power plant designing and operating. (authors)

[en] For a nuclear power plant reactor control rod system power fuse burned event root cause analysis. Through the analysis of system principle for the reactor control rod system and the power cabinet circuit, combined with fuses fusing characteristics and thyristor turn on and off characteristics, the actual measurement data shows that the root cause of fuse burned is the thyristor performance abnormal abnormal performance of thyristor cause a short circuit between two adjacent phase voltage, resulting fuses instantly burned. And gives the maintenance strategy recommendations for improvement the reactor control rod system. (authors)

[en] Objective: To investigate correlation between glycemic excursion by CGMS and diabetic retinopathy among type 2 diabetes mellitus. Methods: Used continuous glucose monitoring system (CGMS) to monitoring glycemic excursion within a day of twenty four patients with type 2 diabetes mellitus, and inspect fundus photography, correlation was analyzed. Results: Glycemic excursion might reveal the risk for diabetic retinopathy better than HbA1c does. Conclusion: Diabetic retinopathy may correlate with glycemic excursion. (authors)

[en] Neutron Source Multiplication method (NSM) in reactor physics experiment was researched. First neutron source multiplication method formula deduced from neutron diffusion equation with external neutron source is different to before one and then it is verified on the sub-critical system. Measurement parameter with NSM is the effective sub-critical neutron multiplication factor k_s with external neutron source and is not effective neutron multiplication factor k_eff. The Critical mass be measured by NSM. The parameter k_eff also is measured by other method. The Experiment indicates that neutron source multiplication method formula deduced is correct. The Parameter k_s depend on external neutron source position in sub-critical system and external source neutron spectrum. The critical mass can be measured by NSM. But the sub-criticality (or parameter k_eff) can not be done. So a puzzle about measurement parameter k_eff with neutron source multiplication method is solved. Finally the relation and difference between parameter k_s and parameter k_eff and the effect of them on the critical extrapolation measurement and nuclear safety is discussed. (author)

[en] Computational analysis of electrostatic microelectromechanical systems (MEMS) requires an electrostatic analysis to compute the electrostatic forces acting on micromechanical structures and a mechanical analysis to compute the deformation of micromechanical structures. Typically, the mechanical analysis is performed on an undeformed geometry. However, the electrostatic analysis is performed on the deformed position of microstructures. In this paper, a new efficient approach to self-consistent analysis of electrostatic MEMS in the small deformation case is presented. In this approach, when the microstructures undergo small deformations, the surface charge densities on the deformed geometry can be computed without updating the geometry of the microstructures. This algorithm is based on the linear mode shapes of a microstructure as basis functions. A boundary integral equation for the electrostatic problem is expanded into a Taylor series around the undeformed configuration, and a new coupled-field equation is presented. This approach is validated by comparing its results with the results available in the literature and ANSYS solutions, and shows attractive features comparable to ANSYS. (general)

[en] The worth of neutron beam with different material was measured with extrapolation method and period method on the miniature neutron source reactor zero power experiment facility. The influence of neutron beam with different material to the reactor criticality was studied. The result can be used for verifying the reactor calculation and neutron beam design. (authors)

[en] According to the current national standard requirement, a maintenance bypass device is designed in HFETR, based on the system structure of emergency shutdown unit of protection system. This paper introduces the bypass principle of 2003 architecture and 1002 architecture, and also has carried on the failure modes and effects analysis to this device. In the end, the analysis and practical application has proved that this maintenance bypass device is successful. (authors)

[en] Plasma disruption constitutes a serious threat to the safety of tokamak devices. The quench rate of current during plasma is closely related to the magnitude of electromagnetic forces and the formation of runaways beam. In this paper, the data of current quench have been statistically analyzed by using 90%-10% of the pre-disruption and are compared with the experimental results in the range of 80%-20%. The experimental results show that there are four different current quench waveforms on HL-2A. The minimum current quench time is 2.6 ms and 2.2 ms, respectively. The statistical distributions of mean current quench time are obviously different in the two different intervals. (authors)

[en] The Absorber ball system is the reserve shutdown system of pebble-bed high-temperature gas-cooled reactor, which participates in the reactor reactivity control and keeps the reactor in sub-criticality. The discharge vessel is the first device through which millions of φ6 mm Absorber balls are pneumatically conveyed from the side reflector back to the ball storage vessel. The Absorber balls are suspended and accelerated by the gas flow inside the discharge vessel, and the study on the conveying performance and the reliability of different discharge vessels is required. The numerical simulation of a new style fluidizing nozzle discharge vessel was performed, the velocity and the pressure distributions were showed. Meanwhile, an experimental study on the discharge vessel using normal temperature air as conveying medium was performed. The simulation result shows that the local resistance coefficient of the discharge vessel is 5.1, and the experiment result shows that the local resistance coefficient of the discharge vessel is 5.7. The results are acceptable for engineering application. (authors)

[en] We review the progress made on power scaling and compact and portable THz sources. By reversely stacking GaP plates, we improved photon conversion efficiency from 25% to 40%, which is the maximum value. As the number of the plates was increased from 4 to 5, the output power was decreased due to back conversion. We also investigated THz generation by mixing two frequencies generated by a single Nd:YLF solid-state laser. The average output power reached 1 μW. By introducing two Nd:YLF crystals, we significantly improved the output power to 4.5 μW. Such a configuration allowed us to generate different output frequencies. We have also reviewed our effort of making the THz source further compact by exploiting passively Q-switched laser pulses.