The Study Of Water Level Control Of Pressurizer Based On Nuclear Power Plant

As a clean and safe energy, nuclear power constitutes the world's three pillars of powers with thermal power and hydropower. Like other countries in the world, china also needs the more economical and more secure nuclear technology to promote the sustainable development of nuclear energy. Although China has been developed nuclear power for more than 30 years, there is still a certain gap in the need of the development of the national economy and the progress of nuclear technology. The mechanisms need to be innovated and the advanced technologies needs to be used to promote the nuclear power construction. Considered that the water level control system in the reactor control system is a very important and typical control system, this paper researched the control system.According to the situation of the power generation in power station, sometimes the power of reactor needed to be changed,this paper studies the water level control system which controls the variation of the water level in the regulator according to the variation of power. Because any value of the power in reactor corresponds to one water level in the regulator. For example, the power decreases from 100% to 90%, the water level in the regulator changes from 62.8% to 58.65%. It needs the control effect of regulator to achieve that value. It can ensure every part of the whole nuclear power plant's safe operation. The water level control system studied in this paper can realize the aim of control water. The work process is: because of the variation of power of the reactor results in the change of the water temperature of the loop. The volume is changed. To ensure the real water level of that power is consistent with the fixed water level, the valve in the RCV (chemistry and volume control) system can change with the power changed. If the real power increases, the water level increases, so the valve will turn down. The purpose is to ensure the water level in the regulator is consistent with the fixed water level. This paper introduces the water level control system can make the real water level reach the fixed value, and the relationship between every value can be observed in the man-machine interface, also the value at some moment.Considered that the core of the Daya Bay water level control system is consist of 15 Simulation Plug-ins, so choose the"function clone"to make the water level control system digital. The digital control system could not only replace the original control system which consisted of several plug-ins, but also compatible with the original analog system, it could be embedded into the nuclear power plant system, and no changes in appearance, but by its internal simulation subsystem had changed into digital subsystems. Since we could not connect with the real regulator to carry out a dynamic test, so established a mathematical model to simulate the dynamic characteristic of the regulator water level, and composed a closed-loop system with the control system, implemented the dynamic. After debugging, the system ran normally. Through the human/machine interface, it showed the running condition of the water level control system. It proved that this digital control system could achieve the function of the original control system, and could be compatible with the external simulation system.The general arrangements of this paper are as follows:Chapter 1: Introduction of nuclear power in the future development and the status in quo, raised the significance of the study.Chapter 2: start with the introduction of the nuclear power and raised the knowledge of the Regulators, analyzed the principle of the regulator water level control system. As well as the composition, structure and function of the control system. It made a basic for the follow chapters.Chapter 3: studied the implementation scheme of the Regulators water level control system, the"function clone"approach. Started with the filtration of the microprocessor, discussed the implementation steps, objectives, and research content, and decided the research scheme of the system.Chapter 4: analyzed the function and the connect relationship of the analog water level control system plug-ins. Researched the running principle of the whole water level control system, and educed the control arithmetic of the control system.Chapter 5: Researched the main controller. We chose the FLEX3500 as the hardware basis, studied the FLEX3500 SBC and the main chip"rabbit", used the control arithmetic in last chapter, programmed with dynamic C, finally educed the whole control system. The controller not only related to D / A and A / D converters, switch values and online communications, but also could implement self-check and keep the step 0.1s.Chapter 6: Made the human/machine interface by the LabVIEW, and debugged the whole system. At this stage, we introduced every part of the human/machine interface and some problems in the debugging process. The control system could not run until composed a closed-loop system with the regulators water level simulation model. In the 10 minutes running, we cut 6 pictures to show the running state. And proved the system in the paper is realizable and better than the analog system by compared the human/machine interface of it with the analog control system.Chapter 7: sum-up and expectation.