JPS61295335A - Apparatus for removing impurity in liquid metal - Google Patents

Abstract

PURPOSE:To constitute the titled apparatus capable of reducing size of apparatus and releasing impurity easily to an outer system, by connecting a liquid metal layer of impurity separating vessel, an exit and an inlet of a cold trap for liquid metal flow by a liquid metal recirculation pipe. CONSTITUTION:If impurity is accumulated at a mesh part 4 in the cold trap 1, valves 11a, 12a of the melt 2 and the exist 3, and valves 5a, 6a of gas flowing pipes 5, 6 are opened, to start regenerating operation. Hereupon, the part 4 is heated by a heater, etc. provided at the trap 1 outer periphery to melt impurity at the part 4. The impurity is sent to a vessel 4 together with liquid metal circulating as the part 4 a liquid metal recirculation pipe 12 impurity separating vessel 14 the liquid metal recirculation pipe 11 the part 4. H2 in the impurity is transferred to cover gas space part from liquid metal, and the purified liquid metal is returned to the trap 1. Repeating the circulation, the impurity accumulated at the part 4 is removed.

Description

DETAILED DESCRIPTION OF THE INVENTION (Field of Industrial Application) The present invention relates to an impurity removal device for removing impurities from liquid metal.

(Prior art) In liquid metal cooled fast breeder reactors, liquid metal is used as a coolant (a typical example of liquid metal is Na;
However, the concentration of impurities in the liquid metal must be sufficiently low to prevent corrosion of the material. For this reason, an apparatus for removing impurities from the liquid metal as shown in FIG. 2 is provided.

In Figure 2, (1) is a cold trap.

A mesh part (4) for capturing impurities is provided in the cold trap (1), and the liquid metal enters the cold trap (1) from the inlet (2).
4), impurities are precipitated and captured. The temperature of the liquid metal changes when it flows through the pipe on the inlet (2) side or when it flows through the upper part of the cold trap (1) and enters the mesh part (4).

The temperature has dropped to lower than the system temperature.

The solubility of impurities is lowered, and the impurities are precipitated and captured in the mesh part (4). The most common impurities are oxygen and hydrogen. When the amount of impurities captured in the mesh part (4) exceeds the capacity.

Cold trap (1) needs to be replaced. In this case, if the line is where liquid metal and impurities flow directly into the reactor core, the cold trap (1) will also be activated to some extent, requiring costly work such as shielding. Processing becomes a problem. For this reason, a backup device is often provided from the beginning, but as shown in Figure 2, the outlet (3) of the cold trap (1) and the hydrogen separator (7) having an adsorbent are connected to recirculate liquid metal. A pipe (12) connects the hydrogen separator (7) and a cold trap (1).
The hydrogen component captured in the mesh section (4) is transferred together with the liquid metal to the hydrogen separator (7), and the mesh section (
A device for removing impurities in liquid metal that restores the performance of 4) is shown. The method of operating this impurity removal device is as follows.

Isolate the cold trap (1) from normal operating conditions. This isolation is achieved by closing valves (2a) (3a). Next, the regeneration operation of the cold trap (1) is started. This regeneration operation is performed using the liquid metal recirculation pipe (11).
Open the valve (lla) (12a) provided in (12),
Start the electromagnetic pump (10) and transfer the liquid metal from the mesh section (4) to the liquid metal recirculation pipe (12) to the hydrogen separator (7).
)→liquid metal recirculation pipe (11) - mesh section (4). At this time, the mesh part (
4) is heated or the like to elute the hydrogen compound into the circulating liquid metal, while the hydrogen compound is adsorbed onto the adsorbent of the hydrogen separator (7).

(Problems to be Solved by the Invention) A problem with the apparatus for removing impurities from liquid metal shown in FIG. 2 is that a relatively large hydrogen separator (7) is required. In addition, in this hydrogen separator (7), since the adsorbent is located in, for example, a nickel tube, it takes a long time for hydrogen to permeate, and as in the case described above, a standby unit is provided so that it can be used as a standby unit even during normal operation. It is necessary to perform playback alternately with the machine.

The present invention addresses the above-mentioned problems by connecting the liquid metal layer of the impurity separation container that separates the impurities in the liquid metal by transferring them to the cover gas space, and the outlet and inlet of the cold trap through which the liquid metal flows. communicated by metal recirculation pipes,
The object of the present invention relates to an apparatus for removing impurities in liquid metal, characterized in that the cover gas space of the impurity separation container and the impurity separator are connected through a gas flow pipe.

The device can be made smaller. Another object of the present invention is to provide an improved device for removing impurities in a liquid metal that can easily release impurities out of the system.

(Means for Solving the Problems) As described above, the device for removing impurities in liquid metal of the present invention separates the impurities from the liquid metal layer of the impurity separation container by moving the impurities in the liquid metal to the cover gas space. The outlet and inlet of the cold trap through which the metal flows are connected by a liquid metal recirculation pipe, and the cover gas space of the impurity separation container and the impurity separator are connected by a gas flow pipe, so that the liquid metal containing impurities is The liquid metal is taken out from the outlet of the cold trap through the recirculation pipe to the impurity separation vessel, and the impurities in the liquid metal are separated into the cover gas space of the impurity separation vessel, and then sent to the impurity separator in the gas distribution pipe system. Since it is guided and captured, there is no need for a large container as in the prior art, and the device can be downsized. In addition, since impurities are captured by the impurity separator in the gas distribution pipe system as described above, when releasing the captured impurities out of the system, the impurity separator is heated and the gas distribution pipe system is removed from the system. All you have to do is open it.
Impurities are easily released from the system.

(Example) Next, the apparatus for removing impurities in liquid metal of the present invention will be explained using an example shown in FIG. 1. (1) is a cold wrap, (2) is an inlet, (3) is an outlet, and The outlet (3) is branched and a liquid metal recirculation pipe (12) is connected to the branch pipe;
The inlet (2) branches into a liquid metal recirculation pipe (
11) is in contact. The same liquid metal recirculation pipe (11
) (12) may communicate directly with the inlet and outlet provided in the body of the cold trap (1). The other end portions of the liquid metal recirculation pipes (11) and (12) are connected to the liquid metal layer of the impurity separation container (14), and the liquid metal recirculation pipe (12) has a liquid metal layer in the middle. Circulation pump (10)
A gas flow pipe (5) is provided in the cover gas space of the impurity separation container (14).
(6) is in contact. Further, an impurity separator (paper trap) (15) having a hydrogen adsorbent and a heater (8) are provided in the middle of the gas flow pipe (6), and a heater (8) is provided in the middle of the gas flow pipe (5). , a gas circulation pump (9) is provided. Note that the impurity separation container (14) is
Any device may be used as long as it has a cover gas or can create a cover gas. Further, the liquid metal recirculation pipe system may be provided with a preheater and a heat insulating material as necessary, and the cover gas piping system may also be provided with a preheating heater and a heat insulating material as necessary. Furthermore, when there is no need to accumulate hydrogen gas, it may be discharged outside the system.

(Function) Next, the function of the apparatus for removing impurities in liquid metal shown in FIG. 1 will be explained. The mesh part (4) inside the cold trap (1)
), the inlet (2) and outlet (3)
Close the valves (2a) (3a) and close the liquid metal recirculation pipe (1).
1) Open the valves (lla) (12a) of (12) and the valves (5a) (6a) of the gas circulation pipes (5) and (6).1) Then open the liquid metal circulation pump (10) and the gas circulation pump (9).
) to start regeneration operation. At this time, the temperature of the mesh part (4) is heated by a heater or the like provided on the outer surface of the cold trap (1), and the impurities are dissolved from the mesh part (4). The impurities dissolved in the mesh section (4) are removed from the mesh section (4) - liquid metal recirculation pipe (1).
2) - Impurity separation vessel (14) - Liquid metal recirculation tube (1
1) - Contained in the liquid metal circulating in the mesh section (4).

It is sent to an impurity separation container (14). Of the same impurities.

Hydrogen has the property of moving from the liquid metal to the cover gas space, and the liquid metal is purified and sent to the cold trap (1).
Return to If you repeat this cycle.

Impurities accumulated in the mesh portion (4) are removed. On the other hand, there is an impurity separator (15) in the gas distribution pipes (5) and (6), and hydrogen gas that has migrated to the cover gas space is captured by the impurity separator (15). At this time, if it is not necessary to accumulate this hydrogen gas, introduce the gas from outside the system into the system (see arrow AI)
On the other hand, this gas is released outside the system (see arrow A2).

(Effects of the Invention) As described above, the device for removing impurities in liquid metal of the present invention separates the liquid metal from the liquid gold r/Iq layer of the impurity separation container which transfers impurities in the liquid metal to the cover gas space and separates the impurities. The outlet and inlet of the flowing cold trap are connected by a liquid metal recirculation pipe, and the cover gas space of the impurity separation container and the impurity separator are connected by a gas flow pipe,
The liquid metal containing impurities is taken out from the outlet of the cold trap through the liquid metal recirculation pipe to the impurity separation vessel, and the impurities in the liquid metal are separated into the cover gas space of the impurity separation vessel. Since the impurity is introduced into the system's impurity separator and captured, the large container required in the conventional method is unnecessary, and the device can be made smaller. In addition, since impurities are captured by the impurity separator in the gas distribution pipe system as described above,
When releasing the captured impurities out of the system, it is sufficient to heat the impurity separator and open the gas flow pipe system to the outside of the system, which has the effect of easily releasing the impurities out of the system.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to these embodiments and can be modified in various ways without departing from the spirit of the present invention.

[Brief explanation of the drawing]

FIG. 1 is a system diagram showing an embodiment of an apparatus for removing impurities in liquid metal according to the present invention, and FIG. 2 is a system diagram showing a conventional apparatus for removing impurities in liquid metal. (1)...cold trap, (2)...inlet, (
3)...Outlet, (5)(6)...Gas distribution pipe,
(11) (12)...Liquid metal recirculation pipe, (14)
... Impurity separation container, (15) ... Impurity separator. Sub-representative patent attorney Shigefumi Okamoto and two others

Claims (1)

[Claims] The liquid metal layer of the impurity separation vessel, in which impurities in the liquid metal are transferred to the cover gas space and separated, and the outlet and inlet of the cold trap through which the liquid metal flows are connected by a liquid metal recirculation pipe, and the impurity separation vessel is An apparatus for removing impurities in liquid metal, characterized in that a cover gas space and an impurity separator are connected through a gas flow pipe.