JPH0434394A - Leakage detector - Google Patents

Abstract

PURPOSE:To reduce the amount of materials of equipment to realize the simpli- city and performance improvement thereof by partially sharing the constituents of a heating device and a leakage detection device. CONSTITUTION:A sharing circuit 8 is connected between heater power supply 9 for supplying a power source to a heater 5 and leakage detection power supply 12 for applying low voltage between the electrodes of leakage detection parts to simplify circuits and the like. Thereby the amount of materials of equipment can be reduced to simplify systems so as to realize performance improvement. The danger of fire and for human bodies can be controlled to improve the safety thereof by easily discriminating the voltage of leakage detection power supply 12 from impedance and heater leakage current from the leakage of liquid sodium so as to set short circuit current to small value when a heater is short-circuited and liquid sodium is leaked.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a liquid metal electric heating device and a leakage detection device.

(Prior Art) In a fast breeder reactor, a liquid metal such as liquid sodium is used as a coolant. If this liquid metal leaks,
In the unlikely event that a leak occurs, it must be detected immediately and countermeasures must be taken, as there is a risk of serious disruption to the grid.

There are various methods for detecting leakage of liquid metal, but a simple and reliable detection method is a contact leakage detection method that utilizes the conductivity of leaked liquid metal.

The second contact-type leak detection method is to cover the container containing the liquid metal with a container or place a tray, and place a counter electrode at the lowest point where the leaked liquid metal collects when a leak occurs. is installed, and the fact that the electrodes are bridged by leaked liquid metal is detected by a change in electrical resistance.

(Problems to be Solved by the Invention) According to the contact-type leakage detection method described above, leakage of liquid metal can be easily detected if the container containing liquid metal is small and simple in shape.

However, in many cases, the shape of containers containing liquid metal is complex, and especially in large-scale facilities, the shape is spatially extensive. Also, in this leak detection method,
Liquid metal leaking from the leakage point flows down the pan or container, reaches the electrode, and is detected. Therefore, if you are trying to improve performance by identifying the leakage point or shortening the detection time, you will have to detect a large number of points. Therefore, there is a problem in that the electrode/receiver requires a large-scale electric circuit to connect the detection section composed of a plate or the like, and the electrodes and the leakage detection section, which are arranged in various spatial locations.

The present invention focuses on the fact that in equipment that contains liquid metal, an electric heating device for melting the liquid metal and keeping it warm is installed at a location similar to the location where the leak detection section is installed. It is an object of the present invention to provide a leak detection device in which the overall system configuration is simplified by sharing some of the components of the leak detection device.

[Configuration of the Invention (Means for Solving the Problems)] In order to achieve the above object, the leakage detection device of the present invention includes: a heater and a leakage detector installed near a container containing liquid metal; a heater power source that supplies power to the heater; a leak detection power source that applies a low voltage between electrodes of the leak detection section; and a heater that detects a decrease in insulation resistance of the heater and a decrease in interelectrode resistance of the leak detection section. The present invention is characterized by comprising: an electric heat/leakage detection device comprising a ground fault/liquid metal leakage detection section; and a shared electrical path connecting the heater and leakage detector and the electric heat/leakage detection device.

(Function) In the device of the present invention, when there is a leakage of liquid metal, the resistance value between the electrodes of the leakage detection part decreases and the current of the leakage detection power supply increases, so the current of this power supply can be measured. This allows you to detect leaks of liquid metal.

Also, if there is a ground fault in the heater, the current of the leakage detection power supply increases, but compared to the leakage current of the heater, the current of the leakage detection power supply at the time of liquid metal leakage is sufficiently large and the area is different, so both can be used. can be determined.

Therefore, it is possible to measure the increase in heater leakage current under normal conditions and monitor the deterioration of the heater, and at the same time, when liquid metal leaks, the leakage of liquid metal can be detected by the large increase in current.

(Example) Next, the present invention will be described in detail with reference to the drawings.

FIG. 1 shows an embodiment of the invention.

In this embodiment, a pipe 2 for transporting the liquid metal 1 is illustrated as a container containing the liquid metal. The pipe 2 is covered with a container 3, and a heat insulating material 4 is filled between the container and the pipe 2. The container 3 has the function of preventing liquid metal from leaking outside from the inside of the pipe 2 and functions as a heat-insulating container, and is made of a conductive material such as metal and is grounded. There is.

Inside the container 3, there is an electric heater 5 for melting and keeping the liquid metal 1 flowing inside the pipe 2 warm, and a leak detector 6 consisting of a pair of electrodes, or a leak detector 6 arranged at appropriate intervals in the length direction of the pipe 2. It is installed in

Riet wire 6a pulled out from one electrode of leak detector 6
is connected to one terminal 52 of the heater 5, and a lead wire 6b drawn out from the other electrode is grounded.

Terminals 5a and 5b of heater 5 and electric heat/leakage detection device 7
are connected to each other by an electric line 8 consisting of a two-core cable.

The electric heat/leakage detection device 7 includes a heater power supply control section 11 composed of a heater power supply 9 and a heater switch 10, a leakage detection power supply] 2, a zero-phase current transformer 13, and a ground fault/leakage detection section 14. and a heater ground fault/liquid metal leak detection section 15.

One terminal of the heater power supply 9 is grounded through a leakage detection power supply 12. Further, the electric line 8 is shared by both the heater power supply control section 11 and the heater ground fault/liquid metal leak detection section 15.

In the leakage detection device having such a configuration, normally, the heater power source 9 is opened and closed by the heater switch 10 to control the amount of heat generated by the heater 4 and melt and keep the liquid metal 1 flowing inside the pipe 2 warm. ing.

Here, when the insulation resistance of the heater 4 decreases, the output current of the zero-phase current transformer 13 increases, which is detected by the ground fault/leakage detection section 14.

Furthermore, when liquid metal leaks, it flows down inside the container 3 and reaches the leakage detector 6, bridging the electrodes, which reduces the resistance between the electrodes and significantly increases the output current of the zero-phase current transformer 13. To increase. This is detected by the ground fault/leakage detection section 14.

In this case, as shown in FIG. 2, the resistance Rm when detecting leakage of liquid metal and the resistance Rh when insulation resistance of the heater decreases are significantly different. As shown in the figure, an amplifier 16 and two separation sections 1
7.18, it is possible to distinguish between the two and detect them. That is, in FIG. 3, after the leakage current detected by the zero-phase current transformer is amplified by the amplifier 16,
A separator 17, 18 makes it possible to distinguish between a liquid metal leak 17a and a heater ground fault 18a, depending on the magnitude of the current.

As described above, according to the present invention, a common connection is made between the heater and the leakage detector, the heater power supply that supplies power to the heater, and the leakage detection power supply that applies a low voltage between the electrodes of the leakage detection section. Since they are connected by an electric line, the electric line etc. can be simplified. This makes it possible to reduce the amount of equipment, simplify the system, and improve performance.

In addition, by setting the voltage and impedance of the leakage detection power supply 12 so that it is easy to distinguish between heater leakage current and liquid metal leakage, and the short-circuit current is small, it is possible to prevent It can reduce fire and danger to the human body and improve safety.

In addition, in the device of the present invention, as shown in FIG. 4, a current detector 20 is used in place of the zero-phase current transformer 13, and the current flowing through the leakage detection power source 12 is detected by the current detector 20. It's okay. Furthermore, as shown in FIG. 5, the leakage detection power supply 12 may also realize low voltage and high impedance specifications by using a low voltage transformer 21.

[Effects of the Invention] As described above, in the leakage detection device of the present invention, by sharing some of the components of the electric heating device and the leakage detection device, the amount of equipment is reduced, and simplification and performance improvement are realized. I can do something.

[Brief explanation of drawings]

FIG. 1 is a configuration diagram showing an embodiment of the leak detection device of the present invention,
Figure 2 is an explanatory diagram conceptually showing the range of resistance and heater leakage resistance when detecting liquid metal leakage in the device of the present invention;
The figure is a configuration diagram showing an embodiment of the separation section of the resistance and heater leakage resistance at the time of liquid metal leakage detection in the device of the present invention, and FIGS. 4 and 5 are configurations showing modified examples of the leakage detection device of the present invention, respectively. It is a diagram. 1...Liquid metal 2...Piping 3...Container 4...Insulating material 5... -...Temperature control heater 6...Leak detector 7...Electric heat/leak detection device 8...
...Electric circuit 9... Heater power supply 10... Heater switch 11...
・Heater power supply control section 12...Leakage detection power supply 13-...Zero phase current transformer 14...Ground fault/Leakage detection section 15...Heater ground fault/ Liquid metal leak detection section 16...Amplifier 17.18...Separation section 20...Current detector 21...Low voltage transformer 8 Gandai Toshiba Corporation

Claims (1)

[Claims] Containers, piping, equipment, etc. containing liquid metal (hereinafter referred to as
a heater and a leak detector installed near the container (simply referred to as a container, etc.); a heater power source that supplies power to the heater; a leak detection power source that applies a low voltage between the electrodes of the leak detection section; An electric heat/leakage detection device comprising a heater ground fault/liquid metal leakage detection section that detects a decrease in insulation resistance and a decrease in interelectrode resistance of the leakage detection section; the heater and leakage detector; and the electric heat/leakage detection device. A leakage detection device comprising: a shared electric line connecting the two;