Flow And Vibration Characteristic Research Of Nuclear Main Pump Under Station Blackout Accident

At present, in China, the nuclear main pumps in all the nuclear reactors in operation and construction rely on imports. The nuclear main pump has been the bottleneck to independent nuclear power technology and domestic manufacture. The nuclear main pump is a component of the primary loop pressure boundary and the only critical rotating equipment in nuclear island, its security, stability, and long-term reliable operation requirements in high-temperature, high-pressure and radiation conditions. It's a high technology system. Studies mainly on nuclear main pump are conducted in this paper from the flow and vibration point of view under station blackout accident.In this paper, in-depth researches are conducted on the design, manufacturing, and other relative issues of nuclear main pump. The differences between ASME-III of United States and RCC-M of France are compared specifically. The development of nuclear standards, safety evaluation, and key technologies etc. in and out of country are summary described. This work has a certain reference value to the design, manufacturing of nuclear main pump and the standard construction.3D models of nuclear main pump impeller and blade are constructed by surface blending function of Pro / E software, Use Ansys software for the modal analysis of the impeller and rotor, obtaining their natural frequencies and mode shapes, further calculated the important safety evaluation parameters such as rotor critical speeds and moment of inertia, which lay the foundation for the future analysis on dynamic response and earthquake response of the rotor system.Through station blackout test of nuclear main pump, the transient vibration, idle flow, idle rotate-speed and other data is measured; the idle rule-curves of flow, rotate-speed and vibration characteristics on housings and shaft are obtained. The test shows that the station blackout accident has certain affection to flow and vibration in nuclear main pump, and has potential hazards to the future security and stability operation in pump. The test results help to understand the operational characteristics of nuclear main pump under station blackout accident. Further works are done on the fourth polynomial curve fitting to idle flow and idle rotate-speed, fitting result as an initial importation conditions in following flow simulation.Nuclear main pump's full 3D simulation of the flow field is conducted; flow characteristics in pump are obtained in the normal operating, deviate from normal operating and station blackout accident conditions; the intuitive graphics of pressure, velocity vector, and particle trace lines in pump including impeller, guide vanes, pump shell, pump axial section and radial section. Research shows that in the blade around the bottom of the back wheel exists a low pressure area, on which has an obvious flow return and large hydraulic loss, and it is the easiest location to produce cavitations, thus, the design should pay sufficient attention. Through further research, flow Q-pressure head H, flow Q- efficiencyηcurves of nuclear main pump characteristic are obtained, compared with the experimental curves, discovered that there is much more relative error while deviate from the operation conditions, this is probably due to the axial entrance and radial export of pump, and this special shape produces more hydraulic loss while operating in deviate from normal conditions. Through the surface integral function, the axial force changes on impeller is obtained, which can provide valuable reference to optimized design, safety assessment and the design of thrust bearing of nuclear main pump.