Study On New-style Hydraulic Control Rod Driving System

Control rod driving mechanism is a significant component to insure the safety and controllability of reactor. It directly performs the role of start-up, shutdown, power regulation and fast scram in accidents. The electromagnet control rod driving mechanism was generally adopted by pressurized water reactor. However, its movement of rod removal and insertion is discontinuous and can't be fine-tuned. It locomotes with a certain design step. In this paper, a new-style hydraulic control rod driving system was put forward by using servo-tube control elements for the design of control rod driving mechanism. Then the theoretical analysis and experimental study was carried out for its application traits. This system has many advantages such as energy conservation, continuous movement and automatical adjustment in small disturbance. It has offered a new idea for the design of control rod driving mechanism.The thesis firstly confirmed the design project of driving cylinder and established the experiment equipment and testing platform of driving system. Then according to the design parameters of driving cylinder, the three- dimensional entity model of its interior flow field was upbuild. By using the Computational Fluid Dynamics program Fluent, the numerical simulation of pressure field, velocity field and static holding flux of driving cylinder was carried out as well as the flow field and resistance coefficient of variable throttle orifice with different structural parameters. Thus the foundation was laid for experimental study and theoretical analysis.In order to ulteriorly reveal the working mechanics of hydraulic driving system, the mathematic model was established to analyze the process of statics, dynamics and rod drop, according to the design philosophy and basic structure. Then the computation program was compiled. The theoretical calculation and analysis was also carried out for the working characteristics of rod holding, removal, insertion and drop. At one time, the experimental study in cold condition was executed on static holding flux, removal and insertion performance as well as rod-drop capacity and time. Thereby, the rationality of device design and the correctness of theoretical model and results were validated.Finally, on the basis of theoretical model forementioned, the hydraulic control rod driving system was taken as independent object of study. The vibratory response and earthquake-resistance capability were analyzed initially. And to calculate and analyse the kinetic characteristic of control rod in condition of hypergravity and weightlessness, the nautical motion process was simulated for surfacing and diving with different acceleration. According to the general specification for machinery and nuclear power plant of naval ships, the system's static holding capacity was theoretically analyzed and calculated in condition of long-term slope, single-degree-of-freedom swing and two-degree- of-freedom swing. Consequently, some theoretical reference was provided for the system application on nautical reactor or removable seawater desalination plant.The thesis only made initial analysis of system's static holding capacity in some special conditions. A few predigestion and hypothesis was adopted in study. Therefore, the theoretical model still needs to be perfected and improved. More in-depth analysis and experimental study should be carried out for the performance of rod removal and insertion in these special conditions, as well as the working characteristic in much more complex condition. In addition, the relevant experimental study also needs to be implemented in heated and high-pressure condition.