KR20100039766A - Continuous electrolytic refining device for metal uranium - Google Patents

Abstract

PURPOSE: A continuous electrolytic refining device is provided to uniformly collect uranium electrodeposits by controlling deattachment point and period of the uranium electrodeposits using an exciter. CONSTITUTION: A continuous electrolytic refining device(1) comprises an electrolytic cell(10), a cathode(20), an anode(40), a metallic uranium collecting unit(50), and a transition metal collecting unit(60). The cathode includes an insulation vibration absorbing member(25) and an exciter(26). The insulation vibration absorbing member fixes an upper plate on an cover plate(12). The exciter transfers exciting force to the cathode through a tie bar(21).

Description

Continuous refinery refiner of metal uranium {CONTINUOUS ELECTROLYTIC REFINING DEVICE FOR METAL URANIUM}

The present invention relates to a continuous refining and refining apparatus for metal uranium, and more particularly, a metal that can be recovered by continuously removing uranium electrodeposits deposited on the cathode by applying vibration or impact force to the cathode using an excitation means. A continuous electrolytic refining apparatus of uranium.

As is well known, the electrolytic refining apparatus for metal uranium used as a nuclear fuel in the prior art is characterized in that an anode basket containing a fragment of spent metal fuel in a molten salt of about 500 ° C. in which uranium trichloride is dissolved, and pure uranium are electrodeposited. It is composed of an iron-based cathode.

In the refining of metal uranium using the electrolytic refining apparatus of the conventional metal uranium, when current is applied, uranium trichloride in the molten salt is reduced and electrodeposited on the cathode, and the chlorine ions separated in the reaction electrically select metal uranium at the anode. To dissolve. Such electrolytic refining of metal uranium can be repeated to separate pure metal uranium.

However, the electrolytic refining process of the metal uranium using the electrolytic refining apparatus of the conventional metal uranium should stop the electrolytic reaction in order to periodically recover the metal uranium electrodeposited on the negative electrode, and the continuous operation takes a long time to recover the electrodeposited material. It is impossible to obtain a large amount of product in a short time.

To overcome these shortcomings and to remove pure metal uranium at high speed, electrolytic pretreatment devices have been reported.

U.S. Patent No. 5,650,053 (July 22, 1997) discloses a section of spent metal fuel in a molten salt of about 500 DEG C in a cathode basket of a porous plate, and several anode baskets are formed inside a cathode. Located outside and applying electricity while rotating the anode basket, the metal uranium in the anode melts and is electrodeposited to the cathode, and the electrodeposited metal uranium is scraped with a ceramic plate attached to the outside of the anode to collect at the lower collecting portion. The device is starting.

 However, the above-described refining apparatus is only part of the metal uranium electrodeposited to the cathode, so that the remaining electrodeposited to continue to adhere to the surface of the negative electrode, and gradually turn into a dense structure difficult to fall.

Therefore, since the electrodeposited material cannot be dropped by the ceramic plate of the anode, the electrolytic refining operation is stopped after a certain period of time, and electricity is reversed to return the electrodeposited material to the anode to reverse electrodeposition. After the surface is cleaned, the electrodeposition operation is performed again as the first time.

This reverse electrodeposition process has the disadvantages of high electricity consumption, low electrodeposition efficiency, and very complicated device. Moreover, in order to recover the lower electrodeposits, the electrolytic reaction has to be stopped and the entire electrode module has to be lifted.

In addition, since the uranium electrodeposit recovery tank is located under the anode basket, undissolved transition element particles generated at the anode are incorporated into the uranium, thereby obtaining a high purity uranium electrodeposition.

Japanese Patent Application Publication No. 10-332880 (December 18, 1998) also dissolves a metal fuel component in cadmium at 500 ° C, electrodeposits it again on an iron-based negative electrode, recovers uranium deposits by a mechanical scraping process, and Disclosed is a refining apparatus which is transferred to a separate uranium / salt separation tank for treatment in order to separate contained salts.

Therefore, the above-described refining apparatus does not need to stop the electrolytic reaction in order to recover the uranium deposits, so that continuous operation is possible and the processing speed can be increased.

However, this forging apparatus also has the disadvantage of being accompanied by a mechanical scraping process since it still uses an iron-based cathode.

Moreover, the use of a pump for electrodeposition transfer has the disadvantage that a large amount of salt and cadmium are simultaneously transferred and undergo an additional distillation process to recover the uranium electrodeposition therefrom.

 On the other hand, Japanese Patent Application Laid-open No. Hei 10-53889 uses a drum-type negative electrode in which a portion is deposited in molten salt for easy recovery of uranium electrodeposited on the negative electrode, and rotates it to separate the uranium electrodeposited material with a scraper. In addition, the present invention discloses a refining apparatus for removing residual salt by injecting argon gas to the surface of uranium deposited on the surface of the negative electrode drum.

However, this refining apparatus also needs a continuous supply of argon, and accompanied by a mechanical scraping process does not fundamentally solve the problems of the conventional apparatus.

An object of the present invention for solving the above problems, continuous electrolytic refining of metal uranium to be recovered by continuously removing the uranium electrodeposits electrodeposited on the cathode electrode by applying a vibration or impact force to the cathode electrode using an excitation means To provide a device.

Continuous electrolytic refining apparatus of the metal uranium of the present invention for achieving the above object has an interior receiving space, the electrolyte is filled with an electrolyte; A cathode part in which cathode electrodes are fixed to a lower side of a heat sink inside the electrolytic cell by connecting bars penetrating the center of the cover plate covering the electrolytic cell; An anode part formed to have a cylindrical shape so as to surround and surround the cathode electrodes, the anode part having an inner accommodating space for accommodating nuclear fuel used therein, and rotatably fixed to an edge portion of the cover plate; A uranium recovery unit which draws out the collected uranium metal to the outside of the electrolytic cell by the first extraction means connected to a lower part of the uranium recovery tank provided below the cathode electrode; And a transition metal recovery part for drawing out the transition metal particles collected in the lower part of the electrolytic cell by a second drawing means connected to the lower part of the electrolytic cell, wherein the negative electrode part is insulated and dust-tightly fixed on the cover plate to an upper plate fixed to the top of the connecting bars. Insulating dustproof member; And an excitation means provided on the upper plate to transmit excitation force to the cathode electrode through the connection bar.

 The insulation dustproof member may be constituted by a dustproof rubber plate, and the insulation dustproof member may include a ceramic plate in contact with a cover plate and an upper plate; And a coil spring interposed between the ceramic plates.

 The excitation means may consist of an electric hammer.

 The negative electrode may include a graphite negative electrode or an iron-based negative electrode including stainless steel.

 It is preferable to further include a screw type stirrer which is rotatably fixed to the center of the cathode electrodes through the cover plate.

 Preferably, the first drawing means and the second drawing means are screw conveyors.

According to the continuous electrolytic refining apparatus of the metal uranium according to the present invention, by applying vibration or impact force to the cathode electrode by using an excitation means, the metal uranium electrodeposited on the cathode electrode can be detached to be continuously and uniformly recovered. .

Further, according to the continuous electrolytic refining apparatus of the metal uranium of the present invention, in addition to the graphite electrode in which the uranium electrodeposits are spontaneously detached by desorbing the uranium electrodeposits electrodeposited to the cathode electrode by applying vibration or impact force to the cathode electrode by an excitation means. The iron-based negative electrode including stainless has the effect of recovering the metal uranium uniformly without mechanical scraping.

In addition, according to the continuous advanced refining apparatus of the metal uranium of the present invention, it has the effect of uniformly recovering the uranium deposits by controlling the release time and period of the uranium deposits using the excitation means.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings so that those skilled in the art may easily implement the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention. In order to clearly illustrate the present invention, parts not related to the description are omitted, and the same or similar components are denoted by the same reference numerals throughout the specification.

1 is a longitudinal sectional view showing a continuous electrolytic refining apparatus for metal uranium according to a first embodiment of the present invention.

1 and 2, the continuous electrolytic refining apparatus 1 of the metal uranium of the present embodiment includes an electrolytic cell 10, a cathode part 20, a screw stirrer 30, an anode part 40, and uranium. The recovery part 40 and the transition metal recovery part 50 are comprised.

The electrolyzer 10 has a cylindrical shape and a lower portion of a funnel so that the upper side has an open inner receiving space, and the electrolyte is filled so that the cathode electrode of the cathode portion 20 and the anode basket of the anode portion 30 are locked. .

The cover plate 12 is provided to cover the upper opening of the electrolytic cell 10, and the cover plate 12 is fixed to the cathode 20, the screw stirrer 30, and the anode 40.

In addition, a plurality of heat sinks 15 for heat dissipation are installed in parallel with each other in the upper side of the electrolytic cell 10.

The negative electrode portion 20 includes a connecting bar 21, an upper plate 22, a lower plate 23, a negative electrode 24, an insulating dustproof member 25, and an excitation means 26.

FIG. 2 is an enlarged cross-sectional view illustrating an enlarged part II of FIG. 1.

Referring to FIG. 2, the connecting bars 21 are installed to pass through holes 12a having equal intervals in the circumferential direction at the center of the disc of the cover plate 12, respectively.

The upper plate 22 is formed in a hollow disc shape and is fixed to the upper end of the connecting bar 21 penetrating through the cover plate 12 in a state spaced apart from the cover plate 12.

Like the upper plate 22, the lower plate 23 is formed in a hollow disc shape, penetrates through the heat sinks 15 installed on the upper side of the electrolytic cell 10, and is fixed to lower ends of the connection bars 21.

The cathode electrodes 24 form a rod shape and extend from the lower plate 23. In the present exemplary embodiment, it is exemplarily arranged in two rows along the circumference of the lower plate 23 so as to increase an opposing area with the anode part 30 formed around the cathode electrodes 24.

The insulating dustproof member 25 is interposed between the upper plate 22 and the cover plate 12 to fix the upper plate 22 on the cover plate 12 in a state insulated and dustproof.

In this embodiment, the insulating dustproof member 25 is an insulating rubber plate 25a. Accordingly, the insulating rubber plate 27 electrically insulates the negative electrode portion 20 and the cover plate 12, and also transmits vibrations and shocks applied by the means 26 to the cover plate 12. To prevent it.

In addition, the excitation means 26 is provided on the upper plate 22 and is configured to transmit vibration and impact force to the cathode electrode 24 through the connection bar 21.

The excitation means 26 in this embodiment illustrates that it is an electric hammer 26a. The electric hammer 26a transmits vibration and impact force to the cathode electrodes 24 through the connecting bar 21 penetrating through the cover plate 12 and the heat sink 15, and the molten salt in which the nuclear fuel used by the electrolyte is melted. In the process of electrolytic refining of uranium from the uranium electrodeposited electrode to be electrodeposited to the cathode electrodes 24 are continuously detached to be taken out of the electrolytic cell through the uranium recovery unit.

As such, the cathode electrodes 24 in this embodiment allow the uranium electrodeposits that are electrodeposited to the cathode electrode by the excitation means 26 to be continuously desorbed, thereby providing stainless in addition to the graphite cathode that causes the uranium electrodeposits to self-desorb. The use of iron-based cathodes, including metal uranium, allows for continuous electrorefining of metal uranium.

That is, in the case of using the graphite anode, the spontaneous detachment of the uranium electrodeposited material from the graphite cathode by the vibration and impact force transmitted from the vibration hammer 26a temporarily promotes a large amount of uranium electrodeposited material, thereby recovering uranium without accumulation and clogging. It is possible to recover continuously and uniformly by the negative.

In addition, even when an iron-based negative electrode including stainless is used, the uranium electrodeposited material is uniformly detached at a desired time point by the vibration or impact force transmitted from the vibratory hammer 26a without a mechanical scraping process, thereby continuously without mechanical scraping process. Allow the metal uranium to be electrorefined.

A screw stirrer 30 may be further included to penetrate the cover plate 12 and the heat sink 15 so as to be positioned at the center of the cathode electrodes 22.

Referring back to FIG. 1, the screw stirrer 30 stirs the molten salt inside the electrolytic cell 10 by the first motor 32 installed in the fixing bracket 13 fixed above the cover plate 12. It is made in the form of a screw so as to rotate in the center of the cathode electrodes 24 and stirred by flowing the molten salt from the bottom to the top.

Therefore, the screw stirrer 30 circulates below the cathode cathodes 22 and flows the molten salts introduced therein, so that metal uranium dissolved in the molten salt can be more easily electrodeposited on the surface of the cathode electrode.

At this time, the screw stirrer 23 is preferably configured to work with the positive electrode portion 30 to be described later, so that turbulence does not occur during the stirring of the molten salt.

The anode portion 40 includes the anode frame 41 and the anode basket 45.

3 is a perspective view illustrating the cathode of FIG. 2 separately;

Referring to FIG. 3, the anode part 40 includes an anode frame 41 rotatably fixed to the lower portion of the cover plate 12, and an anode basket 45 fixed to the anode frame 41. .

As shown in FIG. 1, the anode frame 41 rotates below the cover plate 12 so as to rotate around the cathode electrode 24 by the second motor 42 located above the cover plate 12. It is possible to install.

The anode basket 45 is cylindrical in shape to surround and surround the cathode electrode 24.

The anode basket 45 has an accommodating space for accommodating nuclear fuel used therein between the outer circumferential plate 45a and the inner circumferential plate 45b.

In addition, the anode basket 45 may be formed to be divided into a plurality of arc-shaped baskets 46 along the circumferential direction of the anode frame 41. In particular, the arcuate baskets 46 may be fastened to the anode frame 41 without using a separate fastening member, and may be configured to facilitate individual replacement work.

Thus, the arcuate baskets 46 can individually replace only the arcuate baskets 46 in which the nuclear fuel contained therein is completely dissolved by the electrolyte, so that the entire anode portion 40 can be continuously removed without taking out the electrolytic cell. Electrolytic refining process can be performed.

Hereinafter, the anode basket 45 collectively refers to the respective arc-shaped baskets 46 constituting it. The anode basket 45 extends along the height direction of the outer circumferential plate 45a and the inner circumferential plate 45b, and a plurality of outlets 45c are formed in parallel in the circumferential direction.

4 is a partial cross-sectional view showing the shape of the outlet of the cylindrical basket of FIG.

Referring to FIG. 4, the outlet 45c may be formed in both the outer circumferential plate 45a and the inner circumferential plate 45b of the anode basket 45, and the outlet 45c may be rotated in the anode portion 40. When the molten salt flows from the inside of the positive electrode basket 45 to the outside is formed.

Furthermore, the outlet 45c is formed to be inclined with the cross-sectional center line L of each anode basket 45. In the present embodiment, the outlet 45c is formed to be inclined approximately 45 degrees with the center lines L of the anode basket 45, and further, to be inclined in a direction in which a molten salt flow path is formed in a direction opposite to the rotation direction of the anode portion 40. Is formed.

Accordingly, transition metal sludges of a predetermined size or less remaining in the anode basket 45 without being dissolved by the electrolyte during electrolytic pretreatment of nuclear fuel are discharged through the outlet 45c of the outer plate 45a by the flow of molten salt. To be discharged.

In addition, the inner circumferential plate 45b of the anode basket 45 may be formed of a mesh of less than a predetermined mesh to prevent the transition metal sludge from flowing into the anode portion 40.

In one example, the inner circumferential plate 45b may be made of a stainless steel mesh of about 100 to 325 mesh (mash).

Therefore, the molten salt inside the electrolytic cell 10 is stirred while flowing without generation of turbulence by the positive electrode portion 40 and the screw stirrer 30 that cooperates with it.

The anode portion 40 rotates and flows the molten salt inside the cathode portion 20 to the outside, so that the nuclear fuel contained in the anode basket 45 is more easily dissolved, and the transition metal sludge remaining without dissolving. To the outside through the outlet 45c.

At this time, the discharged transition metal sludge is collected in the lower part of the electrolytic cell 40 by the specific gravity difference with the molten salt.

Referring again to FIG. 1, the metal uranium recovery unit 50 may include a recovery tank 51 formed at a lower portion of the cathode electrode, and a first drawing for drawing out the metal uranium collected at the lower portion of the recovery tank 51 to the outside of the electrolytic cell. And means 52.

The recovery tank 51 is formed in the form of a funnel in the lower portion of the negative electrode portion 20, the metal uranium electrodeposits are removed after being electrodeposited to the negative electrode cathodes 22 in the recovery tank 51.

On the other hand, in the present embodiment, the first drawing means 52 illustrates that the first screw conveyor 52a. The first screw conveyor 52a allows the metal uranium collected under the recovery tank 51 to be continuously drawn out of the electrolytic cell 10.

In addition, the transition metal recovery unit 60 includes a second drawing means 62 connected to the lower portion of the electrolytic cell 40.

 In the present embodiment, the second drawing means 60 exemplifies the second screw conveyor 61, and the second screw conveyor 61 continuously transfers the transition metal sludge collected under the electrolytic cell 10 to the outside of the electrolytic cell. Withdraw.

On the other hand, in addition to using the second screw conveyor 61 for the recovery of the transition metal sludge, it can be used as a conveying means in the exchange of molten salt.

Therefore, the continuous electrolytic refining apparatus 1 of the metal uranium of this embodiment applies vibration or impact force to the graphite or iron-based cathode electrode 24 by using an electric hammer, and is detached from the cathode electrode 24 to the recovery tank 51. The collected metal uranium is continuously drawn out through the first screw conveyor 52a, and the transition metal sludges collected in the lower part of the electrolytic cell 10 are continuously drawn out through the second skew flow conveyor 62a.

Hereinafter, a continuous electrolytic refining apparatus of metal uranium according to a second embodiment of the present invention will be described with reference to the accompanying drawings, and the same reference numerals as those of the first embodiment described above are used for the same reference numerals. Repeated explanations are omitted.

5 is a partially enlarged view of a continuous electrolytic refining apparatus of metal uranium according to a second embodiment of the present invention.

Referring to FIG. 5, in the metal uranium continuous electrolytic refining apparatus 1 of the present embodiment, the insulating dustproof member 25 includes the ceramic plate 25b and the coil spring 25c as compared with the first embodiment described above. Has a difference in configuration.

Here, the ceramic plates 25b are installed to contact the upper surface of the cover plate 12 and the lower surface of the upper plate 22, respectively, so that the cathode electrodes 24 may be connected to the cover plate 12 by the connecting bar 21. The upper plate 22 to be fixed is insulated.

In addition, the coil spring 25c is interposed between the ceramic film plates 25b to transmit the vibration and impact force generated by the electric hammer 26a to the cover plate 12 so as to be transmitted to the cathode electrode 24. To prevent

Hereinafter, experimental examples in which the vibration-desorption characteristics of uranium electrodeposited materials are compared and tested by replacing the iron-based negative electrode and the graphite negative electrode in the continuous electrolytic refining apparatus 1 of the metal uranium according to the first embodiment of the present invention.

Experimental Example 1

In Experimental Example 1, the vibration detachment characteristics of the uranium electrodeposited body were tested using an iron-based negative electrode.

In the present experimental example, a stainless steel negative electrode was used among the iron-based negative electrodes, and the results of observing the desorption behavior of the uranium electrodeposition according to the amplitude (Vibration stroke) of the electric hammer 24 using the stainless negative electrode are shown in Table 1.

The sticking coefficient was measured according to the variation of current density and vibration stroke at LiCl-KCl molten salt temperature of 500 ℃ and UCl3 9wt%. Here, the sticking coefficient was defined as follows.

Therefore, if the sticking coefficient is large, it means that the uranium electrodeposited material is not detached and remains on the surface of the cathode. If the value is close to 0, most of the electrodeposited material is detached.

As can be seen in Table 1, it can be seen that uranium electrodeposits are detached by vibration under most conditions regardless of the current density. In the case of graphite cathodes, self-scraping is performed when the sticking coefficient is 0.05 or less. Since this is defined as dominant, it can be seen that the scraping behavior comparable to the graphite cathode is exhibited by applying vibration under most conditions.

In particular, the experimental results for six current densities showed that the average sticking coefficient of the stainless steel cathode used repeatedly three times was 0.028, which shows the spontaneous detachment characteristic.

This means that even if the cathode is repeatedly used up to three times without a separate cleaning process, the sticking coefficient is not significantly affected under most conditions. It means that it can be recovered.

Experimental Example 2.

In Experimental Example 2, the vibration detachment property of the uranium electrodeposited body using the graphite anode was tested.

6 is a photograph showing the shape of the uranium electrodeposited material using the graphite negative electrode and the graphite negative electrode after vibration desorption.

FIG. 6 (a) shows the shape of the uranium electrodeposited material prior to jabalal elimination during uranium electrolytic refining using the graphite cathode module in the electrolytic refining conditions of Table 2 below.

In order to generate spontaneous desorption during uranium electrodeposition by the graphite anode, more than a certain amount of uranium is electrodeposited so that the load of the electrodeposited body is greater than the electrodeposition adhesion strength on the surface of the graphite cathode. However, when the electrodeposition material is detached at this time, the electrodeposition material accumulates at the inlet of the first screw conveyor 52a, thereby preventing the smooth rotation of the screw.

Therefore, when a certain amount of uranium is electrodeposited on the graphite cathode, it must be forcibly detached so that a controlled amount of uranium electrodeposited material can be introduced into the inlet of the first screw conveyor 52a.

As shown in (b) of FIG. 6, before the spontaneous desorption occurs, a phenomenon in which the electrodeposited material adheres to the electrode surface can be observed. When it is reloaded into the electrolytic cell 10 and the vibration is applied by the upper vibrator, it can be seen that all electrodeposits are detached by vibration even before spontaneous detachment as shown in FIG.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, but many variations and modifications may be made without departing from the spirit and scope of the invention. And it goes without saying that they belong to the scope of the present invention.

1 is a longitudinal sectional view showing a continuous electrolytic refining apparatus for metal uranium according to a first embodiment of the present invention.

FIG. 2 is an enlarged cross-sectional view illustrating an enlarged part II of FIG. 1.

FIG. 3 is an enlarged cross-sectional view illustrating an enlarged part II of FIG. 1 of the continuous advanced refining apparatus for metal uranium according to the second embodiment of the present invention.

4 is a photograph showing the shape of the uranium electrodeposited material using the graphite negative electrode and the graphite negative electrode after vibration desorption.

<Description of Main Reference Signs>

10: electrolytic cell 12: cover plate

20: cathode 21: connecting bar

22: upper plate 23: lower plate

24 cathode electrode 25 insulating dustproof member

25a: insulating rubber plate 25b: ceramic plate

25c: coil spring 26: means having

26a: electric hammer 30: screw stirrer

32: first motor 40: anode portion

41: anode frame 42: second motor

45: anode basket 50: metal uranium recovery unit

51: recovery tank 52: first withdrawing means

52a: first screw conveyor 60: transition metal recovery valve

62: second drawing means 62a: second screw conveyor

Claims (8)

An electrolytic cell having an inner receiving space and filled with an electrolyte; A cathode part in which cathode electrodes are fixed to a lower side of a heat sink inside the electrolytic cell by connecting bars penetrating a central portion of the cover plate covering the electrolytic cell; An anode part formed in a tubular shape so as to surround and surround the cathode electrodes and having an inner accommodating space for accommodating nuclear fuel used therein, and rotatably fixed to an edge portion of the cover plate; A uranium recovery unit which draws out the collected uranium metal to the outside of the electrolytic cell by a first drawing means connected to a lower part of the uranium recovery tank provided under the cathode electrode; And a transition metal recovery part for withdrawing transition metal particles collected in the lower part of the electrolytic cell by a second drawing means connected to the lower part of the electrolytic cell, The cathode portion, An insulated dustproof member for fixing the top plate fixed to the upper end of the connection bars to be insulated and dustproof on the cover plate; And And an excitation means provided on the upper plate to transmit excitation force to the cathode electrode through the connection bar. In claim 1, The insulating dustproof member is a continuous electrolytic refining apparatus of metal uranium, comprising a dustproof rubber plate. In claim 1, The insulation dustproof member, A ceramic plate in contact with the cover plate and the upper plate; And A continuous electrolytic refining apparatus for metal uranium consisting of coil springs interposed between the ceramic plates. In claim 1, The said exciting means is a continuous electrolytic refining apparatus of the metal uranium containing what is an electric hammer. In claim 1, The cathode electrode is continuous continuous refining device of metal uranium made of graphite material. In claim 1, The cathode electrode is a continuous electrolytic refining apparatus of a metal uranium comprising an iron-based cathode containing a stainless material. In claim 1, And a screw type stirrer rotatably fixed to the center of the cathode electrodes through the cover plate. In claim 1, And said first drawing means and said second drawing means are screw conveyors.

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