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The supercritical carbon dioxide (SCO2) Brayton cycle, as a substitute for the steam cycle, can be widely used in a variety of power generation scenarios. However, most of the existing SCO2 cycle studies are restricted to basic thermodynamics research, parameter optimizations, system design in different application fields, and even economic analysis. Considering the load variability and control flexibility of the power generation system, the dynamic performance research of the SCO2 cycle is also crucial, but the work done is still limited. Based on the previous studies, Simulink software is used in this paper to develop a dynamic model of the 20 MW-SCO2 recompression cycle, which specifically includes component models that can independently realize physical functions and an overall closed-loop cycle model. A series of comparative calculation are carried out to verify the models and the results are very positive. The SCO2 recompression power system is built with the developed models and the dynamic model runs stably with a maximum error of 0.56%. Finally, the simulation of the dynamic switching conditions of the 20 MW-SCO2 recompression cycle are performed and the analysis results supply instructive suggestions for the system operation and control.

AP1000 is a two-loop pressurized water reactor (PWR) developed by Westinghouse, which uses the forces of nature and simplicity of design to enhance plant safety and reduce construction costs. Compared to traditional reactor control strategies, the AP1000 adopts an advanced Mechanical Shim (MSHIM) core control strategy, which controls the reactivity and the axial power distribution without the need of boron adjusting. The main control signal of MSHIM is the difference of average core coolant temperature and reference temperature obtained from turbine load. In order to improve the response speed, a mismatch signal obtained by the difference of the nuclear power and target power is introduced as the auxiliary control signal. However, this auxiliary signal may cause the control rod acting too fast, also, the power mismatch channel noise is not suitable as a differential lead control channel. To solve this problem, we remove the nuclear power signal channel, and use the average coolant temperature error as the only control signal. Furthermore, a P controller is added for adjusting the control signal to increase the response speed and reduce the steady error. The proposed method was verified by dynamic performance simulation and compared to the original control system. The calculation results show that the modified power control system could not only simplifies the control logic but also enhances the control performance. And, the proposed method satisfies the needs of reactor core power control and power distribution control. The conclusions have reference value for the engineering practice.

The Brayton cycle with supercritical carbon (S-CO2) as working medium is one of the most promising new nuclear power systems. As the key device during the expansion and compression process in the Brayton power cycle, the turbine and compressor design and performance analysis is difficult for the strong nonlinear properties during the near critical region of S-CO2 medium. The design and analysis of the S-CO2 turbine and compressor is the key point for increasing the power device performance and operation security. As a result, this paper proposes a detail design and analysis method for turbine and compressor in the S-CO2 Brayton power cycle. The MW grade power cycle is used as the research project. The inlet and outlet parameters of the turbine and compressor are determined according to the power cycle scheme. Engineering thermodynamic principles combined with two-zone loss model are chosen to carry out the one-dimensional flow path design for the turbine and compressor respectively. Then the quasi-three dimension design of the flow path is accomplished by stream curvature method. The three dimensional geometry structure of the impeller is designed in detail. On this basis, numerical simulation models of the turbine and compressor are established to analysis the flow field and structural strength vibration in detail. Moreover, the simulation results show that the isentropic efficiency of the compressor impeller is 96.9%. The maximum total displacements of the compressor and turbine impeller are 0.12 mm and 0.106 mm respectively. The maximum von Mises equivalent stresses of the compressor and turbine impeller are 372 MPa and 320 MPa respectively. The impeller can meet the strength safty requiments for the maximum stress values are much less than the yield stress of the material.

The position and speed detection system based on the loop-cable is a non-contact method. It could fulfill the accuracy requirements of the position and speed for the mid-speed maglev train. This paper simply introduces its working principle and describes its basic structure. Considering the maglev train is one kind of traffic tool, the induction loop-cable has to adapt to the long-distance structure. The paper draws the theory about the lossless uniform transmission line and analyses the impedance characteristics of the loop-cable using Telegraphic equations (transmission line equation). As the loop-cable has a special periodic structure, it could be equivalent to the cascade of unit rings. Meanwhile, there is impedance mismatch connection point between the loop-cable and the trackside transmission cable, so the impedance converter is designed to prevent the signal reflection. Finally, the non-uniform factor of the unit ring is analyzed and the coefficients of reflection are given.

Medium-speed maglev train location and speed detection system based on induction loop-cable works in the complex magnetic environment. It is vulnerable to the interference of suspended magnetic field, traction current and electric equipment. The variation of the excitation coil' height and the crosstalk between the signal lines will cause the distortion of the signal, which will affect the positioning precision of the system. The particle filter has the ability to filter non Gauss noise, which is suitable for this system. The results of simulation and experiment show that the particle filter has a good effect in the induction loop system, and can effectively filter out the strong magnetic interference component in the signal.

This paper designs a novel induction looped-cable system based on the characteristics of some conventional induction looped-cable systems. The system realizes the train-ground full-duplex communication function for the maglev train system.

A new design method of testing platform is proposed for the practical problems that exited in relative position detection sensor of high speed maglev train. The models of relative position detection sensor and testing coil are built on the basis of principle analysis. The simulation results illustrate that the controllable switch method by changing the equivalent inductance is feasible to complete the basic detection for relative position detection sensor of high speed maglev train.