JP3199937B2 - Molten salt electrorefining equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the reprocessing of spent metal fuel generated from, for example, a nuclear power plant, the purification and recovery of useful metals contained in the spent metal fuel, and the generation of unnecessary fissile fuel. The present invention relates to a molten salt electrorefining apparatus used for separating a substance.

[0002]

2. Description of the Related Art Conventionally, spent metal fuel generated from a nuclear power plant is reprocessed to purify and recover useful metals such as nuclear fuel components from the spent fuel, and to separate unnecessary fission products. Techniques include, for example, U.S. Pat.
And Japanese Patent Application Laid-Open No. 3-75597 are known.

[0003] In the former, a molten salt electrolyte and a molten metal are housed in a metal container (electrolysis tank), and an anode basket and a cathode basket are immersed in the molten salt electrolyte, and electrolysis is performed while maintaining a predetermined temperature. From the spent metal fuel pieces contained in the anode basket, useful nuclear fuel components and unnecessary fission products contained therein are dissolved in the molten metal.

[0004] Useful nuclear fuel components are plutonium, uranium, zirconium and the like, and alkali metal chloride and alkaline earth metal chloride are used for the molten salt electrolyte, and cadmium and the like are used for the molten metal.

[0005] The latter is in the molten salt electrolytic refining apparatus for reprocessing a spent metal fuels containing impurities, and the molten metal phase at the bottom of the electrolytic cell in common, <br/> electrical on top of the molten salt electrolyte phase It is divided into two types, one in which the spent metal fuel is immersed through the insulating partition and the other in which the cathode is immersed.

On the other hand, for the spent metal fuel , the molten metal phase becomes a cathode, and this molten metal phase is energized so as to become an anode for the cathode in the molten salt electrolyte phase , It is characterized in that anode dissolution of spent metal fuel and electrodeposition and recovery of purified metal fuel on the cathode are performed simultaneously.

[0007]

In the prior art, since the partition is made of an insulating material such as ceramics, if the partition is damaged by thermal shock at the time of temperature rise or mechanical shock at the time of electrode insertion, etc.
There is a problem that the fragments fall into the molten metal phase and are difficult to collect.

Further, in order effectively well dispersed melted molten metal phase in useful fuel components construed dissolved by anodic dissolution, it is necessary to specially install a device for stirring the molten metal.

Further, some of the unnecessary fission products contained in the spent metal fuel fall into the molten metal phase in an undissolved state , accumulate on the bottom of the electrolytic cell, and are periodically taken out due to heat generated by decay heat. There are issues such as necessity.

On the other hand, at the time of deposition on the cathode, if strong stirring is performed by a metal stirring blade, useful metal deposited on the surface of the cathode is stripped off by the fluid force. In addition, there are problems that it is difficult to constantly measure the liquid level of the molten metal, to take out the entire amount of the molten salt and the molten metal during maintenance and inspection, and to replace the heater.

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and can be easily recovered when a partition is broken, and promotes the dissolution of useful components of a fuel dissolved by anodic dissolution into a molten metal phase. , And prevent unnecessary fission products from falling into the molten metal phase, and further stir the molten salt phase without stripping the cathode deposits, constantly measuring the liquid level,
An object of the present invention is to provide a molten salt electrolytic refining apparatus that can be easily handled during maintenance and inspection and that can improve the operation rate.

[0012]

[Summary of the invention of claim 1, an electrolytic cell for accommodating a molten metal phase and the molten salt phase, the al provided in the electrolytic bath the said molten salt phase anodic salt bath and the cathode salt A partition wall for partitioning the bath, a partition fall prevention device provided on the partition wall, a rotating shaft of a stirrer provided through the upper lid of the electrolytic cell, and the anodic salt bath attached to the rotating shaft. an anode basket is immersed accommodated spent metallic fuel within said comprises a precipitate recovery device for continuously recovering negative electrode deposits on the cathode-salt bath, the partition fall prevention device is above the partition wall
A bottomed member that covers the cathode salt bath side and exposes the anode salt bath side
The precipitate recovery device is immersed in the cathode salt bath.
Surrounds the outside of the cathode with a gap and has a tray at the lower end.
And a holder attached to the inner surface of the holder.
A blade in contact with the outer surface of the pole, and
The time when the cathode deposit is sucked and collected together with the molten salt
And a storage pipe .

According to the first aspect of the present invention , thermal shock during electrolysis is performed.
And mechanical load will damage the bulkhead,
Prevents falling of bulkhead pieces by capturing at the bottom of the bulkhead drop prevention device
can do. In addition, the anode salt bath side is covered with bottomed material
The reason for exposing without the
Because it is at the same potential as the phase, the bottomed member is placed in the anode salt bath.
If exposed, useful fuel components will precipitate as metal
This makes it difficult to collect . Precipitate recovery equipment
The cathode deposits deposited on the surface of the cathode
With the blade attached to the holder, peel off, peel off
Cathode deposits collected under the holder from the gap between the cathode and the holder
Fall to the end tray. Collect and distribute the cathode deposits on the pan.
Aspirate with molten salt through tube. This allows the cathode
The precipitate can be continuously collected .

The invention according to claim 2 is characterized in that a melting residue tray and a stirring blade are connected to the rotating shaft below the anode basket via an insulator. Claim 2
According to the invention, be connected by a rotating shaft as part insulating material with a stirrer of molten metal in a basket-like container for the positive electrode dissolution was further established pan for recovering the FP undissolved thereunder Thereby, useful fuel components can be efficiently dissolved in the molten metal, and at the same time, unnecessary insoluble fission products FP can be easily recovered.

According to a third aspect of the present invention, the electrolytic cell is surrounded by
A guard vessel is provided, and a guard pipe is provided at the bottom of the guard vessel.
And connect the bottom of the guard container to the outside of this drain pipe.
Section, connect the guard pipe and the
The de Len tank for connecting the other end of the lens pipe provided, the guard
Be sure to install a freeze valve on the piping and drain piping.
And features .

According to the third aspect of the present invention, the molten salt phase and the molten salt phase
Liquid level gauge for continuously measuring the liquid level of metal phase and molten metal
Seal valve that seals molten metal by solidifying
The unit heater can be divided and removed
It has become .

According to a fourth aspect of the present invention, there is provided
Connect a gas bubbling device to blow gas into the cathode salt bath
It is characterized by having done . According to the invention of claim 4, the molten salt bath is agitated by bubbling of an inert gas, and the cathode is provided with a device for continuously recovering the precipitate, thereby stirring without losing the precipitate. The precipitate can be continuously collected without exchanging.

According to a fifth aspect of the present invention, there is provided an electrolysis cell comprising:
And liquid salt level measurement equipment.
Sign . According to the invention of claim 5, the liquid level measuring device is provided.
By providing an apparatus, the liquid level of the molten salt can be continuously measured because the flow rate when a small amount of inert gas flows at a constant pressure varies depending on the liquid level position of the molten salt. The liquid level of the molten metal can be measured continuously because the superpower due to electromagnetic induction between the pair of coils differs depending on the liquid level position of the molten metal.

According to a sixth aspect of the present invention, the guard pipe is provided with a leak detector.
It is characterized by providing an alarm . According to the invention of claim 6
If a leak detector is installed above the guard pipe of the guard vessel
The molten metal phase from the electrolytic cell or guard vessel
And leakage of the molten salt phase can be detected quickly .

According to a seventh aspect of the present invention, the outside of the guard container is provided.
Is provided with a unit type heater . Claim
According to seventh aspect of the freeze, the molten metal to freeze, for example, freeze-sealing valve for sealing the molten metal by solidification of flaps <br/> Miumu, by increasing the temperature above the melting point of the molten metal by providing a heater The seal valve opens, and the molten metal in the electrolytic cell can be drained to an external drain tank . Further, since the heater can be divided and removed, only the target heater can be replaced without moving the electrolytic cell.

[0021]

[0022]

[0023]

DETAILED DESCRIPTION OF THE INVENTION A first embodiment of the reference while the present invention molten salt electrorefining device 9 from Figure 1 will be described. In FIG. 1, reference numeral 1 denotes an electrolytic cell. The electrolytic cell 1 has an upper lid 2 covered with an upper lid 2, a bottom plate 4 of which is formed with a downwardly inclined surface toward the center, and a drain pipe 5 formed on the bottom plate 4. It is connected.

A rotating shaft 7 of a stirrer 6 is provided at the center of the lower surface of the upper lid 3 so as to be hung in the direction of the bottom plate 4 in the electrolytic cell 1. A residue tray 9 and a stirring blade 10 are sequentially attached. An insulator 11 is interposed on the rotating shaft 7 between the anode basket 8 and the tray 9. The stirrer 6 is fixed to a support 14 installed on the upper surface of the upper lid.

On the lower surface of the upper cover 3, a partition wall 12 and a partition fall preventing wire mesh 13 are suspended so as to surround the anode basket 8, the receiving tray 9 and the outside of the stirring blade 10. On the outside of the partition wall 12 and the wire mesh 13 for preventing falling of the upper lid, respective devices such as a liquid level measuring device 15, a gas bubbling device 16 and a continuous cathode deposit recovery system 17 are provided in the electrolytic cell 1 through the upper lid 3. I have.

A guard vessel 18 is provided so as to surround the outside of the electrolytic cell 1 to prevent leakage of a molten metal phase 24 and a molten salt phase 25 described later. A unit type heater 19 is provided outside the guard container 18, and a guard pipe 20 is connected to a bottom surface of the guard container 18. The guard pipe 20 and the drain pipe 5 are connected to the inlet side of the freeze valve 21, the guard pipe 20 on the outlet side of the freeze valve 21 is connected to the drain tank 22, and the drain pipe 5 is open into the drain tank 22.

The molten metal phase 24 and the molten salt phase 25 are formed at the roots near the bottom of the guard pipe 20 and the guard vessel 18 by electric resistance.
There is provided a leak detector 23 for detecting the leak. A molten metal phase 24 and a molten salt phase 25 above it are contained in the electrolytic cell 1, and the molten salt phase 25 is divided by the partition walls 12 into an anodic salt bath 25 a and a cathodic salt bath 25 b. That is, in FIG. 1, the inside of the partition 12 is an anode salt bath 25a, and the outside of the partition 12 is a cathode salt bath 25b.

FIG. 2 (a) shows a state where the partition wall 12 and a partition wall drop preventing wire mesh 13 as a partition wall drop preventing device are fixed to the upper lid 3 with bolts 26, and FIG. The lower part is shown enlarged. The partition walls 12 are made of, for example, an insulator such as ceramics or silicon nitride (SiN) having an alumina content of 96% or more. The partition walls 12 are covered with a partition wall drop wire mesh 13 in the cathode salt bath 25b and the molten metal phase 24. Even if 12 is damaged, it can hold the debris.

[0029] Here, since the wire mesh 13 not covered cations Gokushioyoku 25 a in the wire net 13 is the same potential as the molten metal phase 24, the wire net 13 is exposed in the anode salt bath 25a You have
This is because the useful fuel component may precipitate as a metal there and it is difficult to recover it. According to experiments, the partition wall 12 is damaged by large debris due to thermal shock or mechanical load.
It has been confirmed that the structure can maintain the damage.

FIG. 3A shows an anode basket 8 and a receiving tray 9.
FIG. 3B shows a state where the anode basket 8, the receiving tray 9 and the stirring blade 10 in FIG. 3A are rotating. The rotation is performed by driving the motor of the stirrer 6. A spent fuel piece 27 is stored in the anode basket 8.

The receiving tray 9 stores the dissolved fission products 28. The saucer 9 is provided with a number of holes 29 around the periphery. Only the undissolved useful fuel component 30 dropped from the anode basket 8 together with the dissolved fission product 28 is dissolved in the molten metal phase 24 and the undissolved residual The fission product 28 is retained.

Since the spent fuel piece 27 which has been reduced in volume from the anode basket 8 and dropped off by the receiving tray 9 is melted and held,
Dissolution is promoted on the pan 9 rotating together with the stirring blade 10, and the dissolved residual fission products 28 insoluble in the molten metal phase 24.
Remains on the pan 9. Molten metal phase due to hole 29 in pan 9
The contact between 24 and the spent fuel piece 27 is facilitated.

Therefore, the undissolved useful fuel component 30 in the spent fuel piece 27 that cannot be completely dissolved electrically is stirred on the receiving tray 9 and held until completely dissolved. Also, the molten metal phase
Noble metal fission products, which have no solubility in 24, remain on the saucer 9 and are easily recovered.

FIG. 4 is a view for explaining the bus bubbling device 16, and FIG. 4A is a cross-sectional view of the electrolytic cell 1 taken along the line AA'-A "in FIG. FIG. 2B is a cross-sectional view taken along the line BB′-B ″ in FIG. That is,
The gas bubbling device 16 includes an argon gas cylinder 31 for storing high-pressure argon gas, a gas pipe 32, a valve 33, a spiral pipe 34, and an annular perforated pipe 36 having a number of gas holes 35.
Are sequentially connected.

Here, when the valve 33 is opened, high-purity argon gas passes through the gas pipe 32, and if it is meandered near the molten salt phase 25, the temperature is increased in the spiral pipe 34 to form an annular perforated pipe.
Reaching 36, gas bubbles 35 form bubbles 37 and the molten salt phase 25
By raising the inside, the molten salt phase 25 is given a stirring effect.

A plurality of high-purity argon gas cylinders 31 for supplying a high-purity argon gas are provided in the circumferential direction, and the distance between the gas holes 35 becomes smaller or the hole diameter becomes larger as the distance from the supply part increases, and the gas bubbles 37 become larger in the circumferential direction. And are arranged so as to be uniform.

Next, the structure of the cathode precipitate continuous recovery system 17 will be described with reference to FIGS. As shown in FIG. 1, the collection system 17 includes a motor 38, a collection device 39,
The recovery pipe 40, the valve 41, the recovered precipitate storage tank 42, the valve 43, and the pump 44 are sequentially connected. In the precipitate recovery system 17, a motor 38 and a recovery device 39 are connected by a rotating shaft 45.

The recovery device 39 FIG. 5 (a), are installed holder 49 having a plurality of windows 48 so as not to rotate around the cathode 46 which rotates as shown in (b). Holder 49
One end of the holder stay 47 is connected to the outside of the
The other end of the stay 47 is connected to the inner surface of the electrolytic cell 1,
The holder 49 is fixed to the inner surface of the electrolytic cell 1 through the holder stay 47.
Is defined. The lower end of the holder 49 is shaped like a saucer.
Have been .

A plurality of blades 50 are fixed inside the holder 49 toward the cathode 46. When the cathode 46 rotates in the direction of arrow 51, the useful fuel component 52 deposited on the surface of the cathode 46 is peeled off and the holder 49 is removed. It dropped into 49 lower saucer shaped, saucer-shaped
And through the recovery pipe 40 attached to the hole portion 53 is transported to the collection deposit storage tank 42 sucked along with the molten salt.

Next, the liquid level measuring device 15 installed in the electrolytic cell 1 will be described with reference to FIG. As shown in FIG. 6, the liquid level measuring device 15 is provided with a coil container 58 inside a protective tube 55 having a plurality of communication holes 54, and a transmitting coil 56 and a receiving coil protected by an insulating material in the coil container 58. 57 is inserted to separate the coil container 58 from the molten salt phase 25 and the molten metal phase 24, and the inside of the coil container 58 is filled with argon gas.

Here, when an alternating current is passed through the transmitting coil 56 by the alternating current power supply 59, a magnetic field fluctuating around is generated. Due to the fluctuation of the magnetic field, an induced electromotive force is generated on the receiving coil 57 side, but this electromotive force is attenuated by the eddy current generated in the molten metal phase 24 when the molten metal phase 24 exists near the coil portion. The liquid level of the molten metal phase 24 with a voltmeter 60
Can be measured from the relationship between the liquid level and the electromotive force measured in advance based on the magnitude of the electromotive force measured in step (1).

A bubbling tube 61 is provided in the protection tube 55, and high-purity argon gas is discharged from the high-pressure argon gas cylinder 62 through the valve 63 into the molten salt phase 25 at a constant pressure. The gas flow at this time varies depending on the liquid level of the molten salt.

That is, when the liquid level is high and the pressure at the opening of the bubbling pipe 61 is high, the gas flow rate decreases, and when the liquid level decreases, the gas flow rate increases. By measuring, the liquid level of the molten salt can be continuously measured from the relationship between the liquid level and the gas flow rate measured in advance.

Incidentally, the drain pipe 5 is normally closed by the freeze valve 21. Freeze valve 21
The heater 66 is cooled by Hiyasusu supplied from refrigerant supply device 65 in U-shaped tube section 74 as shown in FIG. 7, closed I'll be solidified molten metal phase 24 at the U-shaped tube section 74, at the time of drain And the metal in the molten metal phase 24 is opened by melting.

Drained molten metal phase 24 or molten salt phase
25 is temporarily stored in the drain tank 22. Here, the drained molten metal or molten salt can be sent back into the electrolytic cell 1 with the freeze valve 21 opened by pressurizing the drain tank 22 by the pressurizing device 68 via the pressurizing pipe 67. it can. The guard pipe drain 69 is for draining the molten metal or the molten salt remaining in the U-shaped pipe portion 74 of the guard pipe 20 to the drain tank 24 in the event that the molten metal or the molten salt leaks.

The temperature of the electrolytic cell 1 is raised from the periphery by two semi-cylindrical unit type heaters 19 shown in FIG.
It is kept warm. The semi-cylindrical unit type heater 19 is combined with an electrolytic cell holding device 70 for holding an electrolytic cell and a guard container, and covers the outside of the heater 71 with a heat insulating material 72. Can be removed while fixed.

The electrolytic cell 1 has two semicircular unit heaters 19
From the bottom. The semicircular unit heater 19 covers the bottom of the heater 71 with a heat insulating material 72 and is combined with the electrolytic cell holding device 70 to form the semicircular unit heater 19.
Can be removed as well.

[0048] According to the first embodiment, emergency bulkhead
Even if the 12 is damaged, the fragments are retained and can be easily recovered, and the useful fuel component in the molten metal phase 24 can be efficiently dissolved, and at the same time, unnecessary insoluble fission products can be easily recovered. Furthermore, stirring can be performed without losing the precipitate, and the precipitate can be continuously collected without replacing the cathode. Further, the liquid levels of the molten salt phase and the molten metal phase can be continuously measured.

During maintenance, the molten salt and the molten metal can be drained outside, and the heater can be separated and removed, so that only the intended heater can be replaced without moving the electrolytic cell. Due to these effects, continuous operation is possible, the processing speed is high, and maintenance is easy as compared with the prior art.

[0050] Next the form of a second embodiment of the present invention with reference to FIG 9
Explain the state . FIG. 9 shows a wire mesh 13 for preventing the partition walls from falling as shown in FIG.
Extended, in the embodiment described so as to cover the mixing blades 10 installed on the lower anode basket 8 in FIG. 3, bottom obtained by the saucer 9, even if they are corrupted event partition wall 12 is finely , The debris can be completely recovered.

FIG. 10 shows a tray 9 and a stirring blade 10 which are provided below the anode basket 8 of FIG.
In an embodiment in which is made of an insulating material such as ceramics,
The receiving tray 9 is surrounded by a cylindrical edge 73 having a circular shape and a plurality of holes 29 provided therein, and holds a small piece of spent fuel dropped from the anode basket 8. The useful fuel component dissolved in the molten metal phase 24 in the small pieces flows out of the holes 29, and only the dissolved fission products remain.

A plurality of stirring blades 10 integrated with the ceramic receiving tray 9 are attached to the lower portion of the receiving tray 9. The rotating of the anode basket 8 causes the receiving tray 9 and the stirring blades 10 to rotate to rotate the molten metal phase. Stir in 24 to promote mass transfer. Here, alumina (Al ₂ O ₃ ), beryllia (BeO), aluminum nitride (AlN), or the like is used as the ceramic material.

[0053] Next the form of a third embodiment of the present invention by 11
Explain the state . Figure 11 is a third anode baskets 8 for use in a molten salt electrolytic refining apparatus according to the embodiment of the present invention the insulator
FIG. 3 is a view showing the structure of a melting residue tray 9 a and a stirring blade 10 connected by a rotating shaft 7 via 11. The dissolving residue tray 9a and the stirring blade 10 are
Are connected via an insulator 11 to the rotating shaft 7 to which the.

The melting residue tray 9a is divided into a plurality of parts in the circumferential direction of the rotating shaft 7, and the respective melting residue trays 9a are arranged at intervals. A hole 29 through which the molten metal passes is formed on the side surface of the melting residue receiving tray 9a. In addition, the stirring blade 10 may be formed integrally with the bottom surface of the receiving tray 9a by using the dissolved residue.

When the anode basket 8 is energized in the anode salt bath 25a, the spent fuel pieces 27 are electrochemically dissolved in the salt and further transferred to the molten metal phase 24. Anode basket 8
Since the spent fuel pieces 27 stored in the container decrease in volume as the melting proceeds, they fall off the mesh provided on the front surface of the anode basket 8 before the melting is completely completed. Is held in a dissolving residue receiving tray 9a provided in the tray.

According to the present embodiment, the melting residue tray 9a
Has a structure in which a plurality of dishes are installed at intervals, and therefore, the stirring blades
The flow of the molten metal generated by 10 can be more effectively introduced from the hole 29 provided on the side surface of the melting residue receiving tray 9a, and the dissolution of the useful atomic fuel component contained in the melting residue can be promoted.

The dissolved fission product 28 is held in the melting residue tray 9a, which can further promote complete dissolution of the useful nuclear fuel component, and prevents the useful metal fission product from diffusing into the electrolytic system. be able to.

[0058] Next the form of a fourth embodiment of the present invention with reference to FIG 12
Explain the state . Figure 12 is an anode basket 8 for use in a molten salt electrolytic refining method of the fourth embodiment of the present invention the insulator 11
FIG. 3 is a view showing the structure of a melting residue tray 9 b and a stirring blade 10 connected by a rotating shaft 7 via a shaft. The melting residue tray 9b and the stirring blade 10 are connected via an insulator 11 to a rotating shaft 7 to which the anode basket 8 is connected.

The melting residue tray 9b is divided into a plurality of parts in the circumferential direction of the rotary shaft 7 and is installed with an inclination, and the respective melting residue trays 9b are spaced apart from each other. It is installed so as not to go out. A hole 29 through which molten cadmium passes is formed on the side surface of the melting residue receiving tray 9b . Note that the stirring blade 10 may be integrally formed on the bottom surface of the melting residue receiving tray 9b.

The spent fuel strips 27 are electrochemically dissolved in the salt by energizing the anode basket 8 in the anode salt bath 25a, and further migrate to the molten metal phase 24. Anode basket 8
Since the spent fuel pieces 27 stored in the anode basket 8 decrease in volume as the melting progresses, they fall off the mesh provided on the entire surface of the anode basket 8 before the melting is completely completed. Is held in a dissolving residue tray 9b provided in the tray.

Since the plurality of dissolution residue trays 9b in the present embodiment have a structure arranged at intervals between the upper and lower surfaces facing each other, they are generated by the stirring blades 10 provided below the dissolution residue tray 9b. The flow of the molten cadmium can be more effectively introduced from the hole 29 provided on the side surface of the melting residue receiving tray 9b, and the dissolution of the useful atomic fuel component contained in the melting residue can be promoted.

Further, since the dissolution residue receiving tray 9b is installed so that there is no space when viewed from the top, the dissolving residue 28 dropped from the anode basket 8 can be collected in the melting residue receiving tray 9b without any leakage. Therefore, the noble metal fission product is almost completely held in the melting residue receiving tray 9b.

According to the present embodiment , the complete dissolution of the useful nuclear fuel component can be further promoted, and the dissolved residue dropped from the anode basket can be almost completely collected. The effect of preventing diffusion into the electrolytic system can be further improved.

[0064]

According to the present invention, storage is easy when the partition wall is broken, and the dissolution of the useful component of the fuel dissolved by anodic dissolution into the molten metal phase is promoted. In addition, it prevents unnecessary fission products from falling into the molten metal phase, stirs the molten salt phase without stripping the cathode deposits, making it easy to constantly measure the liquid level and handle during maintenance and inspection. Become. Therefore, the amount of undissolved loss of uranium in the spent fuel body is reduced,
It is possible to improve the 稼 Doritsu well as to facilitate recovery of the noble metal fission products.

[Brief description of the drawings]

FIG. 1 is a first embodiment of a molten salt electrorefining apparatus according to the present invention.
FIG. 4 is a vertical cross-sectional view showing a part of the embodiment in a side view.

2A is a longitudinal sectional view showing a partition wall portion in FIG. 1 in an enlarged manner, and FIG. 2B is a perspective view showing the partition wall drop prevention wire mesh shown in FIG.

FIG. 3A is an enlarged longitudinal sectional view showing the periphery of an anode basket in FIG. 1, and FIG. 3B is a perspective view showing a state during rotation in FIG.

4A is a top view of the dissolution vessel container shown in FIG. 1 along the line AA′-A ″ in FIG. 1B, and FIG.
BB'-B "arrow direction sectional drawing of FIG.

5A is a cross-sectional view taken along line AA of FIG. 1B, showing the precipitate recovery system in FIG. 1, and FIG. 5A is a vertical cross-sectional view of FIG.

FIG. 6 is a vertical sectional view showing the liquid level measuring device in FIG. 1 in a partial block.

7 is a longitudinal sectional view schematically showing the vicinity of a guard container and a drain pipe in FIG. 1 in an enlarged manner.

8A is an enlarged longitudinal sectional view of the unit heater in FIG. 1 as viewed in the direction of arrow A in FIG.
FIG. 2B is a plan view of FIG. 2A, and FIG. 2C is a plan view of FIG.

FIG. 9 is a second embodiment of the molten salt electrorefining apparatus according to the present invention.
FIG. 5 is a longitudinal sectional view showing the vicinity of a partition wall in the embodiment .

[Figure 10 (a) is an elevational view showing the anode basket near your <br/> Keru the same second embodiment and FIG. 9, (b) is (a)
Bottom view seen from the direction of arrows BB 'of FIG.

FIG. 11 is a perspective view showing the vicinity of an anode basket in a third embodiment of the electrolytic refining apparatus for molten salt according to the present invention.

FIG. 12 is a perspective view showing the vicinity of an anode basket in a fourth embodiment of the molten salt electrorefining apparatus according to the present invention.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Electrolysis tank, 2 ... Top opening, 3 ... Top lid, 4 ... Bottom plate, 5 ...
Drain piping, 6: Stirrer, 7: Rotating shaft, 8: Anode basket, 9, 9a, 9b: Receiving tray, 10: Stirring blade, 11: Insulator, 12: Partition wall, 13: Wire mesh for preventing partition wall drop, 14 ... Support,
15: Liquid level measuring device, 16: Gas bubbling device, 17
… Continuous cathode deposit recovery system, 18… Guard vessel, 19…
Unit type heater, 20… Guard pipe, 21… Freeze valve, 22… Drain tank, 23… Leak detector, 24… Molten metal phase,
25: molten salt phase, 25a: anodic salt bath, 25b: cathodic salt bath, 26 ...
Bolts, 27 ... spent fuel pieces, 28 ... dissolved fission products,
29 ... hole, 30 ... undissolved useful fuel component, 31 ... argon gas cylinder, 32 ... gas pipe, 33 ... valve, 34 ... spiral pipe, 35 ... gas hole, 36 ... circular perforated pipe, 37 ... argon gas bubble, 38… Motor, 39… Precipitate recovery device, 40… Recovery pipe, 41… Valve, 42… Recovery precipitate storage tank, 43…
Valve, 44 ... Pump, 45 ... Rotary shaft, 46 ... Cathode, 47 ... Holder stay, 48 ... Window, 49 ... Holder, 50 ... Blade, 51
... arrow, 52 ... useful fuel component, 53 ... hole, 54 ... communication hole, 55
… Protective tube, 56… Correlation cork, 57… Reception cork, 58… Coil container, 59… AC power supply, 60… Voltmeter, 61… Bubbling tube, 62… High pressure argon gas cylinder, 63… Valve, 64…
Flowmeter, 65 ... refrigerant supply device, 66 ... heater, 67 ... pressure pressure pipe, 68 ... pressure device, 69 ... guard pipe drain, 70 ... electrolyzer holding device 71 ... heater, 72 ... heat insulating material, 73 ... cylindrical Fu <br/> Chi, 74 ... U-shaped tube portion.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Kenji Fujiki 2-4, Suehirocho, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside the Keihin Office, Toshiba Corporation (72) Inventor Reiko Fujita, Komukai Toshiba-cho, Koyuki-ku, Kawasaki-shi, Kanagawa Prefecture No. 1 Toshiba Corporation R & D Center (56) References JP-A-6-324189 (JP, A) JP-A-7-48687 (JP, A) JP-A-3-75597 (JP, A) 3-73899 (JP, A) (58) Field surveyed (Int. Cl. ⁷ , DB name) G21C 19/44

Claims (7)

(57) [Claims] And 1. A electrolytic cell for accommodating a molten metal phase and the molten salt phase, the electrolytic cell to the provided et the said molten salt phase and a barrier rib partitioning between an anode salt bath and the cathode salt bath, in the partition wall A provided partition wall fall prevention tool, a rotating shaft of a stirrer provided through the upper lid of the electrolytic cell, and a spent metal fuel attached to the rotating shaft and immersed in the anode salt bath. an anode basket, the comprises a precipitate recovery device for continuously recovering negative electrode deposits on the cathode salt bath, preventing the partition wall falls
The tool covers the cathode salt bath side of the partition and covers the anode salt bath side.
It is composed of an exposed bottomed member, and the precipitate collecting device is
Surround the outside of the cathode immersed in the cathode salt bath with a gap
A holder with a tray at the lower end and an inner surface of this holder
A blade attached to and in contact with the outer surface of the cathode;
Connected to the saucer, the cathode deposits together with the molten salt
A molten electrolytic refining apparatus, comprising: a recovery pipe for suction and recovery . 2. The molten salt electrolytic refining apparatus according to claim 1, wherein a melting residue tray and a stirring blade are connected to the rotating shaft below the anode basket via an insulator. 3. A guard vessel surrounding the electrolytic cell, a guard pipe connected to the bottom of the guard vessel, and a guard pipe connected to the bottom of the guard vessel outside the drain pipe. 2. The apparatus for electrolytically refining molten salt according to claim 1, wherein a drain tank for connecting the other end of the drain pipe is provided, and a freeze valve is provided for the guard pipe and the drain pipe. 4. The electrolytic refining apparatus for molten salt according to claim 1, wherein a gas bubbling apparatus for blowing gas to said cathode salt bath through a gas pipe is connected. 5. A liquid level measuring device for molten metal and molten salt is provided in the electrolytic cell.
The electrolytic refining apparatus for molten salt according to the above. 6. The molten salt electrorefining apparatus according to claim 3, wherein a leak detector is provided in the guard pipe. 7. The molten salt electrorefining apparatus according to claim 3, wherein a unit type heater is provided outside the guard container.