Nuclear Reactor Coolant Pump and Its Passive Shutdown Seal

Abstract

The invention discloses a nuclear reactor coolant pump and a passive shutdown sealing device thereof. The passive shutdown sealing device comprises a sealing ring, a split ring and a fusible spacer block. The sealing ring is a closed circular ring, the split ring is provided with a longitudinal opening, and the fusible spacer block is a segmental arc having the same cross section as the split ring and is embedded into the longitudinal opening of the split ring so that the fusible spacer block and the opened split ring can form a spliced ring together. Under a normal working condition, the sealing ring and the spliced ring surround a pump shaft of the nuclear reactor coolant pump circumferentially in a spaced mode; under a station blackout working condition, the fusible spacer block is fused and fails, and the split ring is closed to hold the pump shaft tightly under pretightening force. Compared with the prior art, being only provided with the three elements, the passive shutdown sealing device not only can meet the shaft seal completeness requirement under the station blackout working condition without depending on an emergency shaft seal injection system but also has the advantages of being simple in structure and achieving firm double-layer sealing.

Description

technical field [0001] The invention belongs to the 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 It is a structural diagram of an existing nuclear reactor coolant pump, which is composed of a motor 10, a hydrostatic shaft seal assembly 12 and a hydraulic component 14 from top to bottom, and the pump shaft runs through the center of the entire coolant pump; the reactor coolant is composed of a The impeller at the lower end of the pump shaft pumps, which is sucked in through the bottom of the pump casing and flows up through the impeller, and then discharged through the guide vanes and an outlet connection on the side of the pump casing. [00...

AI Technical Summary

Problems solved by technology

However, most of the existing passive parking sealing devices 24 have many components and complex assembly, which not only makes the shaft seal assembly more difficult and costly to manufacture, but also tends to cause seal failure due to failure of one or more components

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