1.Fundamental Science on Nuclear Safety and Simulation Technology Laboratory, Harbin Engineering University, 145-1 Nantong Street, Nangang District, Harbin,150001, Heilongjiang, P.R China(yumingrui2010@sina.com)

Abstract: This paper introduces the structure and working principles of the servo-piston hydraulic control rod drive mechanism(SHCM), which can be moved continuously and has self-lock capacity. The steady state characteristics of SHCM are simulated using FLUENT codes. Based on comparison with the experimental results, the simulation is proven to be credible as a tool to describe the steady state characteristics. Finally, the influence of structural parameters is analyzed to obtain an optimal design. The experimental results indicate that the traction of the servo-tube is larger in the starting and braking stages. The resistance coefficient of SHCM increases gradually in the starting and lifting stage, and then tends to be stable. This coefficient has a maximum value while the inlet pressure is low. Performance norms of SHCM, such as the anti-disturbance ability and positioning accuracy, are tested, the anti-disturbance ability of the actuator is strong while the inlet pressure is fluctuating. The positioning accuracy is high regardless of the action process (lifting or not).

Keyword: control rod drive mechanism; hydraulic drive; internal; anti-disturbance