Thermomagnetic sliding bush stop sealing device for nuclear reactor coolant pump

Abstract

A thermomagnetic sliding bush stop sealing device for a nuclear reactor coolant pump comprises a sliding bush base and a sliding bush. The sliding bush base and a shaft are in interference fit, the sliding bush and the shaft are in clearance fit, the sliding bush is sleeved in the sliding bush base, a first seal ring, a second seal ring and a third seal ring are arranged on the sliding bush which is made of metal materials, and the sliding bush base is made of magnetic materials. The sliding bush is internally provided with two symmetric spring cavities, springs are arranged in the spring cavities, and the sliding bush base is provided with a hole. The sliding bush base and the sliding bush are attracted to compress the springs while the hole is sealed by the sliding bush. When a primary seal of the nuclear reactor coolant pump fails, high-temperature process fluid makes the sliding bush base lose magnetism, magnetic force between the sliding bush and the sliding bush base disappears, the sliding bush moves to the primary seal until being tightly pressed on the wall of a pump cavity under the action of spring force and pressure of the high-temperature fluid in the pump cavity, and the high-temperature process fluid in the pump cavity is prevented from leaking outwards. The thermomagnetic sliding bush stop sealing device is passive and free of external gas supply.

Description

technical field [0001] The invention belongs to the technical field of nuclear main pumps, and in particular relates to a thermomagnetic sliding sleeve parking sealing device for nuclear main pumps. Background technique [0002] In severe accidents, in order to ensure that the radioactive fluid in the nuclear main pump of the reactor does not leak, the nuclear main pump needs to be equipped with a shutdown seal. One of the existing nuclear main pump parking seals is driven by high-pressure nitrogen. The high-pressure gas generates pressure on the sealing piston, pushing the sealing piston to move towards the stepped shaft, and compressing it on the stepped shaft. The sealing ring on the contact surface realizes the sealing of the radioactive fluid. . There are also devices that rely on thermal fluid to drive molten metal. This device requires a relatively large amount of thermal fluid, and therefore requires a certain amount of leakage. [0003] Inadequacies of the existin...

AI Technical Summary

Problems solved by technology

There is also a device that relies on thermal fluid to drive the molten metal. This device requires a relatively large amount of thermal fluid, so a certain amount of leakage needs to occur

[0003] Inadequacies of the existing technology and design: the shutdown sealing device for the nuclear main pump does not have passive characteristics, is dependent on the external high-pressure nitrogen source, and is not reliable enough. If the high-pressure gas source is lost at the same time in a serious accident, the shutdown seal Impossible to operate, the sealing function fails, and a large amount of radioactive fluid leaks

Using thermal fluid to melt low-melting point metals, the amount of leakage is relatively large

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