Fan of a containment atmosphere monitoring system

Abstract

A containment building atmospheric monitoring system fan comprising a volute (1), an explosion-proof motor (2), a motor heat-dissipating shield (3), a rear lateral plate (4), a reinforced backward-curved impeller (5), and a cowling ring (6). The reinforced backward-curved impeller (5) and the cowling ring (6) are mounted within the volute (1). The cowling ring (6) is arranged behind the reinforced backward-curved impeller (5). The rear lateral plate (4) is mounted behind the volute (1). The explosion-proof motor (2) is mounted on the rear lateral plate (4). The reinforced backward-curved impeller (5) is connected onto a shaft of the explosion-proof motor (2). The cowling ring (6) is fixed onto the rear lateral plate (4) via a fastener. The motor heat-dissipating shield (3) extends over the exterior of the explosion-proof motor (2) and implements a static sealed connection with a lateral surface of the volute (1). An explosion-proof motor junction box (17) is arranged above the motor heat-dissipating shield (3) and is connected to the explosion-proof motor via a connecting cable. The containment building atmospheric monitoring system fan fully meets requirements in terms of aerodynamic performance and safety features such as resistance against earthquakes, radiation, accidents, and explosions, thus fully implementing autonomation of the fan.

Description

technical field [0001] The invention relates to a fan, in particular to a fan used in a containment atmosphere monitoring system of Hualong No. 1 advanced pressurized water reactor nuclear power unit. Background technique [0002] In the advanced pressurized water reactor nuclear power unit, the fans are mainly used for exhaust and air flow in the nuclear power unit. The fans used in the existing second-generation semi-nuclear power unit are ordinary centrifugal fans. With the promotion of the "Hualong One" project of the water reactor nuclear power unit, the current ordinary centrifugal fan cannot meet the requirements. The specific reasons are: [0003] The motor of the existing centrifugal fan is exposed to the air, and there is no problem in the operation of the fan exposed to the air under normal operating conditions. Reactor cooling treatment, at this time, boric acid will directly cover the surface of the motor. Relevant data show that all existing structure motors i...

AI Technical Summary

Problems solved by technology

[0002] In the advanced pressurized water reactor nuclear power unit, the fans are mainly used for exhaust and air flow in the nuclear power unit. The fans used in the existing second-generation semi-nuclear power unit are ordinary centrifugal fans. With the promotion of the "Hualong One" project of the water reactor nuclear power unit, the current ordinary centrifugal fan cannot meet the requirements. The specific reasons are:

[0003] The motor of the existing centrifugal fan is exposed to the air, and there is no problem in the operation of the fan exposed to the air under normal operating conditions. Reactor cooling treatment, at this time, boric acid will directly cover the surface of the motor. Relevant data show that all existing structure motors in the world cannot meet the requirements of protection level under this working condition, because a large amount of boric acid will enter the inside of the motor and cause the motor to fail. As a result, the fan stops running, and the fan cannot pump out a large amount of hydrogen generated after the boric acid encounters the high-temperature gas in the reactor. With the increase of the amount of hydrogen, the containment will explode, such as the Fukushima nuclear power plant accident in Japan

[0004] In addition, the volute of the existing centrifugal fan adopts a square welded structure, and the "Hualong No. 1" project requires that after a loss of water accident (LOCA) in the reactor, the fan needs to be kept under a pressure of 0.63MPa for 10 minutes. Leakage, which makes the ordinary steel plate welded square structure, whether it is a steel plate or a weld, cannot meet this requirement. If a leak occurs, the gas delivered by the fan-hydrogen will directly combine with the high-temperature gas in the reactor, and an explosion accident will also occur at this time

[0005] In addition, the existing centrifugal fans use forward-curved impellers. Since the hump inevitably appears in its performance curve, it is very easy to cause the "surge" condition of fan damage when operating under multiple working conditions.

[0006] At the same time, the "Hualong No. 1" project incorporates the advanced design concept of "active and passive", the main technical indicators and safety indicators meet the latest safety requirements in my country and the world, and the containment shell increases the equipment load for emergency measures in case of accidents. When the volume, motor power, and weight of the fan remain unchanged, the performance parameters of the fan increase by 20%, the radiation resistance dose increases by 10 times, and the seismic acceleration increases by 1.5 times. Similar products at home and abroad cannot meet this requirement

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