A heat pipe reactor (HPR) is a kind of modular small reactor with broad application prospects, and its dynamic characteristics and nuclear power control are essential to the safe and stable operation of nuclear power plants. Taking the MegaPower HPR as an example, the dynamic characteristics of the HPR are analyzed, and its power control method is designed in this paper. Based on the lumped parameter idea, the equivalent processing of the structure of the HPR core is carried out, and the main parameters of the heat pipe heat exchanger are designed at first. A lightweight dynamic model of the HPR is established using a thermal resistance network, and the accuracy of the model is verified using the solution of the model under the steady-state full power condition. Then, the dynamic characteristics of the HPR without a controller are analyzed respectively with the disturbance reactivity and mass flow rate, indicating strong self-stability and self-regulation of the HPR. Finally, a reinforcement learning (RL) controller based on the twin delayed deep deterministic policy gradient (TD3) algorithm is designed for the HPR power control, and it is adjusted through appropriately setting states, network structures, reward functions, etc. To verify the performance of the controller, a step response simulation ranging from 100%FP to 90%FP, a compound conditions simulation, and a large load change simulation are carried out, respectively. The results show that the RL controller can find the optimal control strategy through training. Meanwhile, it significantly improves the dynamic and steady-state performance of nuclear power compared with uncontrolled case and PID controller case, and it has the ability of power control under all operating conditions.
Stall affects the safety of aircraft flight.Although the traditional stall warning system improves the safety by adopting the method of synchronizing the clock of multi-processors,the reliability of the system is reduced,and the complexity becomes high.To improve the reliability and reduce the complexity of the stall warning system,the inter-core data interaction and data consistency checking functions of heterogeneous dual-core processors are used to realize the high security design of the stall warning system.Firstly,a suitable processor is selected based on the overall design.Then,the inter-core communication mechanism is compared and selected based on the selected heterogeneous dual-core processor.Finally,the dual-core data transmission tasks are reasonably assigned.The test results show that by utilizing the shared memory communication mechanism in the dual-core processor for data transfer,the data transfer interaction is safer,faster,and more efficient.The method of consistency checking to the solved data in the same processor improves the correctness of the output instructions,enhances the safety performance of the system,and meets the requirements of the stall alarm system for high reliability and high security.In addition,the selection of heterogeneous dual-core processors for residual design is also applicable to other types of systems.
The status of research on high temperature measurement technology and development of temperature sensors is analyzed and summarized.Firstly,the situation of AMS 2750G standard is briefly introduced,as well as the status of research and application of the new concept of calibration of temperature measurement system,i.e.,online calibration.The concepts of offline calibration,online calibration,and the relationship between the two,as well as the development and application of portable online calibrators and thermocouples with calibration holes series are introduced.Then,the development and application of refractory metal thermocouple that tungsten rhenium thermocouple is elaborated in detail,including the characteristics and classification of tungsten rhenium thermocouple,the international leading anti-oxidation technology,and the performance of tungsten rhenium thermocouple at home and abroad is compared.Finally,the research and application of localization of imported temperature sensors are summarized,including the localization research of special thermocouples for multi-purpose furnace and carburizing furnace,thermocouples with calibrated holes,and special thermocouples for glow ion nitriding furnace,etc.,as well as the work of replacing precious metal thermocouples with inexpensive metal and refractory metal thermocouples.This research will provide new ideas for practitioners in the high-temperature measurement industry to select suitable temperature sensors.
Aiming at the problem of insertion and assembly of shaped components,a kind of insertion head that can stably insert and assemble shaped components is designed.Firstly,the ball screw sub drive system is applied to the design of the insertion head lifting mechanism,and the servo motor is selected through theoretical calculation.Then,ADAMS motion simulation software is used to simulate the lifting and rotating motion of the insertion head to verify the reliability of the calculation results and the stability of the structure.Finally,the insertion head is installed in the shaped insertion machine for the insertion test,the relevant data in the process of insertion movement is measured by NYCe motion control system.The test results show that:the maximum speed of the lifting movement of the insertion head is close to 1 m/s,and the one-way movement time is within 0.012 s,which meets the design requirements;the displacement change of the clamping jaw center of the rotating mechanism in the simulated movement process is kept within±0.015 mm,which indicates that the rotary movement is relatively smooth,and the accuracy is in line with the insertion requirements.The test results verifies the utility of the insertion head.The study provide a basis for the subsequent optimization of the performance of the insertion head and enhance the insertion efficiency.
In the field of nuclear sodium-cooled fast reactors,sodium pressure transmitters are essential for monitoring the pressure parameters of sodium process loop.The needs of high temperature,prevention of sodium liquid leakage,and detachable calibration of the sodium process loop are the main factors considered in the functional design of the sodium pressure transmitter.The study of the sodium pressure transmitter includes:the process connection is welded to prevent leakage of sodium liquid;the material used to receive the liquid is Austenitic heat-resistant stainless steel 316H,which solves the problem of high temperature and corrosion resistance;the separation structure consisting of positive and negative flanges of the remote transmission components realizes the function of removability;after the disassembling and separation of the transmitter's normal temperature components,the sealing design of the cavity structure formed by the high temperature components and the pipeline of the sodium liquid and the protection principle are analyzed.Sodium pressure transmitter for sodium bench high temperature impact test,separation mechanism disassembly and secondary installation impact error test are carried out.The test results all meet the requirements.The design and realization of the detachable sodium pressure transmitter meets the special needs encountered in the nuclear power sodium-cooled fast reactor demonstration project.The innovative design of its remote separation pressure transmission mechanism has reference for the application of pressure instruments in other fields.
