Nuclear reactor coolant pump and passive power-off sealing device thereof

Abstract

The invention discloses a passive power-off sealing device of a nuclear reactor coolant pump. The passive power-off sealing device comprises a complete sealing ring and a complete limiting ring, wherein the complete sealing ring can be at a starting position and a non-starting position, and the complete limiting ring can be softened when the state conversion temperature is reached; when the temperature of the limiting ring is below the state conversion temperature, the sealing ring surrounds a pump shaft of the nuclear reactor coolant pump in the circumferential direction and keeps a clearance from the pump shaft under the supporting action of the limiting ring; and when the temperature of the limiting ring is equal to the state conversion temperature or above the state conversion temperature, the limiting ring is softened or melted, the sealing ring loses the support of the limiting ring and holds the pump shaft tightly, and therefore a reactor coolant can be prevented from flowing along the pump shaft. Compared with the prior art, the passive power-off sealing device of the nuclear reactor coolant pump has the advantages that only the two elements, namely, the sealing ring with the sealing function and the limiting ring with the limiting function are arranged, the sealing ring does not depend on the external force from the non-starting position to the starting position, in the whole sealing process, the structure is simple, and sealing is reliable.

Description

technical field [0001] The invention belongs to the technical field of nuclear power, and more specifically, the invention relates to a nuclear reactor coolant pump and a passive shutdown sealing device thereof. Background technique [0002] In a pressurized water reactor nuclear power plant, the hydrostatic shaft-sealed coolant pump is a single-stage, single-suction, vertical mixed-flow pump driven by a three-phase induction motor. figure 1 Shown is a structural schematic diagram of an existing nuclear reactor coolant pump, which sequentially includes a motor 10, a hydrostatic shaft seal assembly 12, and a hydraulic component 14 from top to bottom, wherein the pump shaft runs through the center of the entire coolant pump, and the reactor coolant Pumped by an impeller mounted on the lower end of the pump shaft, it is sucked in through the bottom of the pump casing and flows upwards through the impeller, then discharged through the guide vanes and an outlet connection on the ...

AI Technical Summary

Problems solved by technology

However, most of the existing passive parking sealing devices 24 have a large number of components and complex assembly, which not only increases the difficulty and cost of shaft seal assembly manufacturing, but also tends to cause seal failure due to failure of one or more components

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