JP2635618B2 - Electromagnetic pump for liquid metal - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial application field) The present invention relates to a liquid metal electromagnetic pump mainly used as a drive pump for liquid metal flowing through a main cooling system pipe of a fast breeder reactor plant.

(Prior Art) Generally, in a fast breeder reactor plant, a mechanical pump is mainly used to drive fluid metal flowing through a main cooling system pipe. However, the mechanical pump applies a discharge pressure to the coolant by the rotation of the impeller, so that there is a rotating part,
A complicated design is required for the shaft seal, the bearing, and the like.

On the other hand, in the case of the electromagnetic pump, as shown in FIG. Has a core 5 and a coil 6 wound around the core 5
In addition, a magnetic field is generated by applying a current from the external power supply 4 to apply a driving force to the liquid metal 1 according to Fleming's left-hand rule.

As described above, the electromagnetic pump has no driving unit, is simple in structure, and has high strength and reliability. However, an electromagnetic pump that does not use a superconducting magnet has a lower input / output energy efficiency than a mechanical pump, and is therefore used as a small flow rate pump in an auxiliary cooling system.

(Problems to be Solved by the Invention) As described above, since the mechanical pump has a rotating part, auxiliary equipment such as an oil system is required, so that the mechanical pump has a complicated structure. Also, at the time of pump trip, it is necessary to provide a flywheel on the main motor from the viewpoint of core fuel protection and to design to satisfy the ghost down requirement. On the other hand, when an electromagnetic pump is used as a drive pump for the main cooling system, it is impossible to give inertia to the pump itself when power is lost, so the coolant flow rate suddenly decreases when the pump trips, and the reactor is cooled. Becomes impossible.

The present invention has been made in consideration of the above-described problems, and a mechanical pump that has been made and that reduces the rate of decrease in the coolant flow rate even when the electromagnetic pump used as a drive pump for the main cooling system of the fast breeder reactor plant loses power. An object of the present invention is to provide an electromagnetic pump for liquid metal using a superconducting magnet having the same function.

[Configuration of the invention]

(Means for Solving the Problems) In a Faraday-type electromagnetic pump using a superconducting magnet as the magnetic pole of the electromagnetic pump, a current is supplied from an external power supply to the superconducting magnet driving circuit, and the circuit is cut off while generating a magnetic field. Then, the current from the external power supply is switched to the electrode circuit, the electromagnetic pump is started, and the liquid metal as the coolant is driven. When the power is lost, the circuit switching device causes the current flowing in the superconducting magnet driving circuit to flow to the electrode circuit, thereby maintaining the function of the pump.

(Operation) Since electric inertia is added to the electromagnetic pump, the rate of decrease in the coolant flow rate can be reduced even when the power is lost.

(Embodiment) An embodiment of the present invention will be described below with reference to FIG. 1 and FIG.

FIG. 1 shows an embodiment of a liquid metal electromagnetic pump using a superconducting magnet according to the present invention. An electrode 3 welded to the side of the duct 2 through which the liquid metal 1 flows, a main body composed of superconducting magnets 7 placed above and below the duct 2, and an external power supply 4 for supplying current to the electrodes 3 and the superconducting magnet 7 in parallel. A first switch A8 for closing the superconducting magnet drive circuit, and a second switch for cutting off the current supplied from the external power supply 4 to the superconducting magnet drive circuit.
Consists of B9.

FIG. 2 shows the operation mode of the switch of the superconducting liquid metal electromagnetic pump according to the present invention.

When the superconducting magnet 7 is driven, the switch A8 is turned off (open) and the switch B9 is turned on (closed) to supply current from the external power supply 4 to the coil of the superconducting magnet 7, and the superconducting magnet 7 is turned on. To generate a magnetic field.

Next, at the time of switching from the time of driving the superconducting magnet to the time of pump operation, the switch A8 is turned on, the superconducting magnet driving circuit is closed, and the switch B9 is turned off. Cut off the supply current. As a result, a driving force is generated in the liquid metal 1 in the duct 2 by the magnetic field from the superconducting magnet 7 and the current supplied from the external power supply 4 via the electrode 3, and the electromagnetic pump enters an operating state.

Next, at the time of switching from the time of pump operation to the time of power loss, the switch A8 is turned off, the superconducting magnet drive circuit is opened, and the switch B9 is turned on, so that the current flowing through the superconducting magnet drive circuit is turned on. Through the electrode 3 and the duct 2
By flowing the liquid metal 1 inside, the sudden stop of the function of the electromagnetic pump can be prevented, and the flow rate of the liquid metal 1 as the coolant can be secured for a certain time.

〔The invention's effect〕

The superconducting liquid metal electromagnetic pump according to the present invention uses the current circulating in the superconducting magnet drive circuit even when the power is lost, thereby adding an electric inertia. Can be reduced. In other words, when the power of the mechanical pump is lost, an electromagnetic pump having the same function as rotating the impeller and securing a certain amount of coolant flow by the mechanical inertia of the flywheel attached to the main motor is provided. it can.

Therefore, the reliability and safety of the fast breeder reactor plant are improved, and auxiliary equipment such as an oil system is not required as compared with a mechanical pump, and it is a static device without rotating parts, and Since there is no free liquid level and the flexibility of piping layout is large, it is possible to simplify the plant system and the operation control.

[Brief description of the drawings]

FIG. 1 is a block diagram showing one embodiment of the liquid metal electromagnetic pump of the present invention, FIG. 2 is a diagram showing an operation mode of a switching valve used in the present invention, and FIG. 3 is a diagram showing a conventional Faraday type electromagnetic pump. FIG. DESCRIPTION OF SYMBOLS 1 ... Liquid metal, 2 ... Duct 3 ... Electromagnetic, 4 ... External power supply 5 ... Iron core, 6 ... Coil 7 ... Superconducting magnet, 8 ... 1st switcher A 9 ... 2nd Switch B

Claims (1)

(57) [Claims] 1. A duct through which a liquid metal flows, electrodes welded to side surfaces of the duct, superconducting magnets disposed above and below the duct, and an external power supply for supplying current to the electrodes and the superconducting magnet in parallel. In the configured liquid metal electromagnetic pump, a first switch for opening and closing the superconducting magnet driving electric circuit, and a second switch for cutting off a supply current from the external power supply to the superconducting magnet driving electric circuit. The first switch is closed to open when the external power is lost, and the second switch is closed from open to allow the current flowing through the superconducting magnet drive electric circuit to flow to the electrodes. Characteristic electromagnetic pump for liquid metal.