KR101598851B1 - Separation method of dissolvable material from spent nuclear fuel and pyroprocessing having the method - Google Patents

Abstract

The present invention provides a method for separating a dissolved element from spent nuclear fuel in a front step of an electroreduction process. The method for separating a dissolved element to prevent the effect of the dissolved element to the electroreduction process includes (a) a step of inputting process salt to the spent nuclear fuel containing the dissolved element and eluting the dissolved element from the spent nuclear fuel; (b) a step of maintaining spent nuclear fuel remaining after eluting the dissolved element with a solid state, and maintaining process salt dissolved by the dissolved element with a liquid state, and separating the solid state from the liquid state; and (c) a step of precipitating the dissolved element in the process salt.

Description

TECHNICAL FIELD [0001] The present invention relates to a method for separating dissolved elements from a spent nuclear fuel, and a method for converting a spent fuel into a spent fuel including a spent fuel,

The present invention relates to a method for separating dissolved elements from spent fuel at all stages of an electrolytic reduction process.

The spent fuel metal conversion technology is a technology that enables the spent fuel remaining after nuclear power generation to be recycled and reused. Spent fuel metal conversion technology is being studied as part of the development of next generation nuclear power technology along with sodium fast cooling furnace technology.

The electrolytic reduction process has been studied as a shear process for the metal conversion of metal oxides in an electrochemical process that constitutes a pyrolytic process, and the metal-converted raw material is taken over by an electrolytic refining process, which is a subsequent process. The electrolytic reduction process is generally an electrochemical process using a Li ₂ O catalyst and a molten salt of LiCl. Since the Li metal produced in the electrolytic reduction process can reduce various metal oxides, the electrolytic reduction process can be applied to the production of various metals such as TiO ₂ , Ta ₂ O ₅ and UO ₂ from spent nuclear fuel.

Explaining UO ₂ as an example of an electrolytic reduction process, an electrolytic reduction process using a Li ₂ O-LiCl molten salt is performed by the following main reaction.

2O ₂ ^- > O ₂ + 4e ^-

(2) 4Li + + 4e ^- ? 4Li

Equation _{(3) 4Li + UO 2 →} 2Li 2 O + U

Equation (1) is the reaction when an inert electrode such as platinum is used as an oxidation electrode. In the oxidation electrode, electrons are generated through the oxidation of oxygen ions. In the reduction electrode, Li metal is produced by the reaction as shown in formula (2). Generally, a basket type containment vessel is used as the reduction electrode, and the oxide (for example, UO ₂ ) contained in the containment vessel and the Li produced in the reduction electrode react as shown in equation (3) to produce U metal and Li ₂ O . By such a mechanism, the concentration of Li ₂ O catalyst is theoretically kept constant while the oxide is being reduced.

  The problem arises when this process is applied to spent fuel containing various metal oxides. Typically, the following two problems arise.

The first problem is electrode damage. The electrochemical process is generally controllable and operates under conditions that minimize side reactions. Since most of the metal oxides contained in the spent nuclear fuel are extremely low in solubility in the LiCl molten salt, they are mostly recovered as a metal conversion material (for example, U) in the containment vessel as in the reactions of the above formulas (1) to (3). However, a very small amount of dissolved solute in LiCl is concentrated in the LiCl salt during the electrolytic reduction process, and some of them are caused by electrochemical reaction or chemical reaction, which causes damage or inactivation of electrodes such as platinum . For example, Cs, Ba, Rb, Sr, and Te among the elements contained in the spent nuclear fuel are mostly released from the spent nuclear fuel and exist in the molten salt. Among them, Te forms an alloy with Pt or forms a composite oxide involving Li, resulting in damage of the anode. Of the rare earth elements, Eu has a high solubility in LiCl and elutes most of them, and has high electrochemical activity, which can act as a cause of damage to the anode like Te.

  The damage of the anode is a primary problem. Another problem is that the dissolved salts of the electrolytic reduction process should be discarded and replaced periodically because the dissolved sources are concentrated in LiCl as the electrolytic reduction process is repeated. In a general electrolytic reduction process other than the electrolytic reduction process of the spent fuel, the molten salt is not replaced unless the molten salt is further injected. However, due to the nature of the spent fuel, disposal and replacement of the molten salt are indispensable for the present level of technology. The disposal and replacement of molten salt means an increase in radioactive waste, and it can also be considered as a cause of deteriorating the integrity of the electrolytic reduction process.

Accordingly, a method for performing the metal conversion process after removal of the dissolution source causing the above-described problems must be provided before introduction into the electrolytic reduction process. Through this, a systematic approach should be developed that limits the formation of Li and the reduction of metal oxides for the metal conversion to the main reaction, and separates and removes the elements that can be concentrated in the molten salt.
In addition, the technology of the background of the invention refers to the following prior patent documents.
Patent Registration No. 10-0766516 (Oct. 15, 2007)

It is an object of the present invention to provide a method for separating dissolved elements from spent nuclear fuel at the previous stage of the electrolytic reduction process and preventing adverse effects of the dissolved elements on the electrolytic reduction process in advance.

Another object of the present invention is to provide a method for separating dissolved resources from spent nuclear fuel at the previous stage of the electrolytic reduction process and preventing the problem of replacing the molten salt in the electrolytic reduction process by concentration of the dissolved source .

According to an aspect of the present invention, there is provided a method for separating a dissolved source from a spent fuel by adding spent fuel containing dissolved elements to a process salt, Eluting the dissolved source; (b) separating the solid phase and the liquid phase from each other while maintaining the spent nuclear fuel eluted and remaining in the solid phase and maintaining the process salt in which the dissolved source is dissolved in a liquid phase; And (c) precipitating the dissolved source in the process salt.

According to an embodiment of the present invention, the step (a) includes the steps of: (a1) introducing the spent nuclear fuel into a cathode basket to be used as a cathode of an electrolytic reduction process; (a2) charging the cathode basket into a dissolved source separation device filled with a process salt; And (a3) activating an agitator of the dissolved-organic separator to promote dissolution of the dissolved source from the spent nuclear fuel.

Wherein the dissolved source separation apparatus comprises: a reactor formed to receive the process salt; A flange having a plurality of heat sinks to cover the reactor to limit heat loss of the process salt; And a stirrer for promoting dissolution of the dissolvable material. In the step (a2), a holder connected to the negative electrode basket is inserted into the reactor through the flange, and the holder is mounted on the flange The negative basket may be immersed in the process salt.

The negative electrode basket may be formed in a mesh shape so as to pass the liquid phase through the solid phase in the separating step (b).

The separating step (b) is performed while maintaining the temperature of the gas phase part formed between the interface of the liquid phase and the heat dissipation plate at a temperature higher than the melting point of the process salt, The cathode basket may be stepped up to expose it stepwise above the interface of the liquid phase.

Wherein the holder comprises a plurality of pinholes arranged in a loading direction of the cathode basket, and in the separating step (b), the cathode basket is lifted and a fixing pin is inserted into the pinhole exposed on the flange, Can be repeated for each pinhole.

When the cathode basket is completely exposed to the interface of the liquid phase, the cathode basket may be transferred to the electrolytic reduction process.

(C) precipitating (c) a step of (c1) adding a phosphite capable of phosphating and precipitating the dissolved source to the liquid phase; (c2) dispersing argon gas in the liquid phase to induce a reaction between the phosphide and the dissolved source; And (c3) raising the temperature of the liquid phase, and then dispersing the oxygen gas to oxidize the dissolved source and precipitate in the process salt.

Further, in order to realize the above-mentioned problem, the present invention discloses a method for converting spent fuel into a spent fuel including a method for separating dissolved resources. A method for converting a spent fuel into a metal is a method for converting a spent fuel into a spent fuel including an electrolytic reduction step to cause an electrode damage in the electrolytic reduction step and to remove dissolved elements concentrated in the process salt of the electrolytic reduction step And separating the spent nuclear fuel from the spent nuclear fuel at the previous stage of the electrolytic reduction process, wherein the method for separating the dissolved nuclear fuel comprises the steps of: (a) adding the spent nuclear fuel containing the dissolved raw material to the process salt Eluting the dissolved source from the spent nuclear fuel; (b) separating the solid phase and the liquid phase from each other while maintaining the spent nuclear fuel eluted and remaining in the solid phase and maintaining the process salt in which the dissolved source is dissolved in a liquid phase; And (c) precipitating the dissolved source in the process salt.

According to the present invention having such a constitution as described above, it is possible to remove the dissolved elements that perform chemical or electrochemical behavior in the electrolytic reduction step before the electrolytic reduction step before the electrolytic reduction step, thereby suppressing the side reaction in the electrolytic reduction step. Thus, the influence of the dissolved elements can be minimized even in the subsequent process after the electrolytic reduction process.

Further, the present invention can minimize the concentration of the dissolved source generated in the electrolytic reduction process, thereby increasing the replacement cycle of the process salt used in the electrolytic reduction process. Increasing the replacement cycle of the process salt means that the amount of salt waste is reduced. Therefore, the present invention can improve the soundness of the spent fuel metal conversion process.

In addition, the present invention can improve the efficiency of the radionuclide management by collectively removing and managing the dissolved nuclides which can be dispersed while being subjected to various processes for processing spent nuclear fuel at the initial stage.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is an illustration of a separation apparatus capable of separating dissolved elements from spent nuclear fuel using the present invention; FIG.
FIG. 2 is an illustration of a separation apparatus capable of separating dissolved elements from spent nuclear fuel using the present invention; FIG.
FIG. 3 is a flow chart of a method of separating dissolvable sources according to an embodiment of the present invention. FIG.
FIG. 4 is a conceptual diagram showing a step of eluting a dissolved source from spent nuclear fuel. FIG.
5 is a conceptual view showing a step of separating a solid phase from a liquid phase.
FIG. 6 is a conceptual diagram showing a step of precipitating dissolved elements into a process salt. FIG.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, a method of separating a dissolved source material according to the present invention will be described in detail with reference to the drawings. In the present specification, the same or similar reference numerals are given to different embodiments in the same or similar configurations. As used herein, the singular forms "a", "an" and "the" include plural referents unless the context clearly dictates otherwise.

FIG. 1 and FIG. 2 are illustrations of a separation apparatus 100 capable of separating dissolved elements from spent nuclear fuel using the present invention. FIG. 1 shows a process in which a flange 110 is coupled to a reactor, and FIG. 2 shows a state in which a flange 110 is coupled to a reactor.

The separator 100 is configured to receive a high temperature reactant, such as a process salt, and is particularly adapted to limit the occurrence of heat loss from the high temperature reactant to the outside. The separation apparatus 100 includes a reactor 120, a flange 110,

The reactor 120 includes a first reactor 124 having a hollow to accommodate the process salt and a second reactor 122 configured to enclose the first reactor 124.

The first reactor (124) is disposed inside the second reactor (122).

The second reactor 122 may be disposed in contact with the heater 130 and may include a latching portion 127. The engaging portion 127 may be formed in a different shape such as a concavo-convex or the like so as to correspond to the lower surface of the movable heat sink 113, although the portion of the second reactor 122 is shown as being stepped. In addition, the movable heat radiating plate 113 may be formed so that the lower portion of the movable heat radiating plate 113 is stepped to be mounted on the latching portion 127.

The heater 130 is configured to surround the outer circumferential surface of the second reactor 122. The heat transferred from the heater 130 is a heat source for maintaining the process salt filled in the first reactor 124 at a temperature above the melting point do.

The process salt contained in the reactor 120 is very important in the present invention to minimize the heat loss to the outside in order to realize the separation of the solid phase and the liquid phase. The flange 110 covers the reactor 120 to limit the generation of heat loss from the process salt filled in the reactor 120 to the outside. The flange 110 includes a lid portion 111, a rod 112, fixed heat sinks 115 and 117, and a movable heat sink 113.

The lid portion 111 is formed to cover the inlet of the reactor 120 by a load. The lid part 111 can be joined to the reactor 120 using a separate fastening member.

The rod 112 is formed so as to protrude from one surface of the lid part 111. On the basis of when the flange 110 is coupled to the reactor 120, the rod 112 extends from the flange 110 toward the process salt. The cross section of the rod 112 is preferably formed in a circular shape to facilitate the vertical movement of the movable heat radiating plate 113, but it may be formed in a cross section other than a circular shape. In the figure, two rods 112 are provided on the flange 110, but the number of the rods 112, so that the movable radiating plate 113 and the fixed radiating plates 115, 117 can be stably coupled to the rods 112, Can be increased.

The fixed heat sinks 115 and 117 may be provided in plural and may be disposed on both sides of the movable heat sink 113 to prevent the movable heat sink 113 from being separated. The fixing heat sinks 115 and 117 may have a size corresponding to the hollow portion of the second reactor 122 and the sizes of the plurality of fixed heat sinks 115 and 117 may be different from each other. In particular, the plurality of fixed heat sinks 115 and 117 may be spaced apart from each other so as to form a plurality of low-thermal-conductivity air layers to further reduce the heat loss of the process salt.

The movable heat sink 113 is formed to be movable along the rod 112. The movable heat sink 113 may be formed to lower the load 112 by the load to seal the reactor 120. More specifically, the movable heat radiating plate 113 and the rod 112 are formed with a clearance such that sliding occurs on the surfaces contacting with each other. Accordingly, when the flange 110 is not fully engaged with the reactor 120 as shown in FIG. 1, it can be downwardly moved by the load, and can be brought into contact with the stationary heat sink 115 immediately below.

On the other hand, when the flange 110 is fully engaged with the reactor 120, as shown in FIG. 2, the lower surface of the movable heat sink 113 is mounted on the corresponding latching portion 127. Accordingly, the movable heat radiating plate 113, which has been in contact with the fixed heat radiating plate 115 directly under the load, relatively moves along the rod 112 by the load, is placed in the engaging portion 127, and the reactor 120 is sealed . Closure of the reactor 120 means to reduce heat loss.

The fixed heat radiating plate 115 directly below the movable heat radiating plate 113 and the fixed heat radiating plate 117 positioned immediately below the movable heat radiating plate 113 define a movable range of the movable heat radiating plate 113. The movable range of the movable heat sink 113 can be determined by the heat sinks disposed at the bottom of the two fixed heat sinks 115 and 117. The movable heat sink 113 may be supported by a fixed heat sink 115 disposed immediately below. Accordingly, the movable heat sink 113 can be prevented from deviating.

Referring to FIG. 1, when the flange 110 is coupled to the reactor 120, the stepped portion formed on the movable heat radiating plate 113 is placed on the latching portion 127, and the movement of the movable heat radiating plate 113 is stopped. However, other components of the flange 110, other than the movable heat sink 113, continue to move until the lid 111 is placed in the second reactor 122. This structure can minimize the heat loss of the process salt not only when the flange 110 is fully bonded to the reactor 120 but also when the flange 110 is bonded to the reactor.

When the flange 110 is separated from the reactor 120, the movable heat radiating plate 113 is held in the engaging portion 127 until lifted by the fixed heat radiating plate 115 immediately below. This structure is thus able to minimize the heat loss of the process salt not only when the flange 110 is fully engaged with the reactor 120 but also when the flange 110 is separated from the reactor 120.

The stirrer 140 is configured to stir the process salt. The stirrer 140 is formed so as to be rotatable in a state in which at least a part of the stirrer 140 is immersed in the process salt.

The cathode basket 150 is formed to receive spent fuel. The cathode basket 150 may be called a basket except for the name cathode, but it is referred to as a cathode basket 150 because it is taken over by a uranium oxide electrolytic reduction process and used as a cathode. However, the function of the cathode basket 150 accommodating the spent nuclear fuel is not changed.

The cathode basket 150 is connected to the holder 160. At least a portion of the holder 160 is mountable to the cover 111 of the flange 110. The holder 160 can be inserted into the separating apparatus 100 through the holes formed in the lid 111 and the heat sink. When the holder 160 is inserted into the separating apparatus 100, the cathode basket 150 connected to the holder 160 can be immersed in the process salt filled in the first reactor 124.

A plurality of pinholes 161 are formed in the holder 160. The plurality of pinholes 161 are arranged along the direction of inserting or withdrawing the holders 160 into or from the separating apparatus 100. When the handle 162 of the holder 160 is pulled to insert a fixing pin (not shown) into the pinhole 161, the fixing pin can be fixed to the lid 111 to fix the position of the holder 160.

FIG. 3 is a flowchart of a method of separating a source of dissolved matter according to an embodiment of the present invention. 4 to 6 are conceptual diagrams corresponding to the respective steps of FIG. 3, and therefore, reference may be made to the drawings of FIG. 4 to FIG. 6 in a portion necessary for the explanation of FIG.

The dissociative element separation method disclosed in the present invention can be carried out using the separation apparatus 100 described with reference to Figs. However, the description of FIGS. 1 and 2 is merely an example of implementing the method of separating dissolved elements, so that the present invention is not necessarily implemented by the separating apparatus 100, but may also be implemented by other apparatuses .

The method of separating the dissolved source material includes a step (S100) of eluting the dissolved source, a step (S200) of solid-liquid separation of the solid phase and the liquid phase, and a step (S300) of precipitating the dissolved source material.

First, in step S100 of dissolving the dissolved elements, the spent nuclear fuel is charged into the cathode basket 150 to be used as a cathode of the electrolytic reduction step. This step can be explained with reference to Fig.

FIG. 4 is a conceptual diagram showing a step (S100) of eluting dissolved elements from spent nuclear fuel.

In FIG. 4, A indicates spent fuel, B indicates a dissolved source eluting from spent fuel, and C indicates a process salt.

The spent nuclear fuel contains soluble elements that can be dissolved in the process salt. Dissolve source dissociation refers to an element with high solubility in a process salt, and refers to an element in which about 99% or more of the salt is dissolved in the process salt to be present as a chloride. Dissociative elements include, for example, Cs, Ba, Rb, Sr, Te, and the like.

The process salt may comprise at least one of a LiCl molten salt and a LiCl-KCl eutectic salt. The selection of the process salt may vary depending on the temperature setting in the solid-liquid separation step (S200). For example, the process using LiCl-KCl eutectic salt may be set to a temperature lower than the temperature of the process using LiCl molten salt.

Next, the cathode basket 150 is charged into the dissolved-organic separator 100 filled with the process salt.

In order to charge the anode basket 150 into the dissolved-element separator 100, the cathode basket 150 into which the spent fuel is charged is connected to the holder 160. Then, the cathode basket 150 is inserted into the interior of the separating apparatus 100 through the lid 111 of the flange 110 and the holes of the heat sinks 113, 115 and 117. When the holder 160 is mounted on the lid 111 of the flange 110, the cathode basket 150 connected to the holder 160 is immersed in the process salt.

The cathode basket 150 may be formed in a mesh shape to allow the solid phase to pass through and to pass the liquid phase. In this case, when the cathode basket 150 is immersed in the process salt, the process salt flows into the cathode basket 150 through the hole of the cathode basket 150. Accordingly, the spent nuclear fuel can be immersed in the process salt.

When the spent nuclear fuel is immersed in the process salt, the dissolved elements contained in the spent nuclear fuel are naturally eluted into the high temperature process salt because of the high solubility in the process salt. In this process, the stirrer 140 may be selectively operated to promote the elution of the dissolved components. When the agitator 140 is operated, it is possible to shorten the time required for elution of the dissolution member.

Referring again to FIG. 3, after the dissolution of the dissolution source is induced, the solid phase and the liquid phase are separated from each other (S200). This step separates the solid phase and the liquid phase while maintaining the remaining spent fuel in a solid phase and keeping the dissolved process solute dissolved in the liquid phase. For convenience of explanation, the solid phase means the spent fuel remaining after elution of the dissolved components, and the liquid phase means that the dissolved components and the dissolved salts are dissolved. This step will be described with reference to Fig.

5 is a conceptual view showing a step S200 of separating the solid phase and the liquid phase from each other.

To separate the solid phase from the liquid phase, the cathode basket 150 is lifted stepwise to expose the solid phase stepwise above the liquid phase interface.

The holder 160 is formed with a plurality of pinholes 161 arranged in the loading direction or insertion direction of the cathode basket 150. The cathode basket 150 is lifted by using the holder 160 and the fixing pin 163 is inserted into the pinhole 161 exposed on the lid 111 to keep the solid phase exposed on the liquid interface . By repeating this process for each pinhole 161, the solid phase can be exposed stepwise above the interface of the liquid phase. When the cathode basket 150 rises above the interface of the liquid phase, the liquid phase rising above the interface along the solid phase flows down through the holes formed in the cathode basket 150 onto the interface of the liquid phase filled in the separation apparatus 100, and solid-liquid separation is performed.

For solid-liquid separation, the temperature of the process salt must first be maintained above the melting point of the process salt, and the temperature of the gas phase part formed between the liquid interface and the heat sink must be higher than the melting point of the process salt .

The temperature of the process salt must be maintained above the melting point of the process salt so that the process salt in which the dissolved source is dissolved can be maintained in the liquid phase. The temperature of the gas phase is maintained at a temperature higher than the melting point of the process salt so that the liquid phase (the liquid phase temporarily located in the gas phase) rising above the interface of the process salt along the solid phase in the process of lifting the cathode basket 150 And then flows down to the interface of the liquid phase filled in the first reactor 124, and separation of the solid phase and the liquid phase can be performed through such control.

It is preferable that the solid phase and the liquid phase are separated stepwise. Since the cathode basket 150 is made of metal, its thermal conductivity is high. Therefore, when the temperature of the gaseous phase is lower than the melting point of the process salt, the liquid phase which goes up to the gaseous phase along the solid phase in the solid-liquid separation step can be solidified by cooling. When the solid phase and the liquid phase are separated stepwise by using the pinhole 161 and the fixing pin 163, it is possible to prevent solidification of the liquid phase in the gas phase portion, and the liquid phase, which has risen to the gas phase portion along the solid phase, Can flow down onto the interface of the liquid phase filled in the reaction chamber (100).

The process salt for solid-liquid separation may be a LiCl molten salt or a LiCl-KCl eutectic salt depending on the set temperature. If the melting point of the LiCl molten salt is used, the temperature of the process salt may be set at about 650 ° C, and if the LiCl-KCl eutectic salt is used, the temperature of the process salt may be set at about 500 ° C.

In the present invention, it is possible to use a dissolvable inorganic separator (100) having a movable heat sink (113) that can move up and down in order to improve the heat insulating property in the solid-liquid separation process. In the solid-liquid separation experiments using 6 kg of LiCl molten salt as a process salt, it was confirmed that the temperature of the gaseous phase was maintained at 614 to 645 ° C when the temperature of the molten salt was maintained at 650 ° C, which is higher than the temperature of the LiCl molten salt. When the solid phase of the negative electrode basket 150 was reduced after the solid-liquid separation, the salt content in the reducing material was found to be about 5 wt%.

Referring again to FIG. 3, after the solid-liquid separation, a step S300 of precipitating the dissolved elements follows. In addition, when the cathode basket 150 is completely exposed to the interface of the liquid phase, the cathode basket 150 can be transferred to the electrolytic reduction process. The cathode basket 150 is used as the cathode of the electrolytic reduction process. Since most of the dissolved resources are removed in the cathode basket 150, problems that have been pointed out as problems in the electrolytic reduction process can be solved.

The step S300 of precipitating the dissolved source in the process salt will be described with reference to Fig.

FIG. 6 is a concept showing a step (S300) of precipitating a dissolved source in a process salt.

As the solid-liquid separation is repeated, the enrichment of the nuclides continues in the process salt. As the solid-liquid separation is repeated, a high concentration of nuclear species is present in the process salt. As a result, the cathode basket 150 is exposed to a process salt having a high concentration of nucleus species.

In order to stabilize the nuclides, it is necessary to precipitate the dissolved source in the process salt.

In this step, the solid-liquid separation is carried out and a phosphite capable of printing and precipitating the dissolved source is added to the remaining liquid phase. Then, the argon gas is dispersed in the liquid phase to induce the reaction between the phosphite and the dissolved oxygen. Finally, the temperature of the liquid phase is raised, and then the oxygen gas is dispersed to oxidize the dissolved source and precipitate in the process salt. In Fig. 6, B indicates the precipitated dissolution source.

Through this process, the nuclides present in the dissolved phase can be precipitated in the oxidation and process salts, and the spent nuclear fuel can be prevented from being exposed to the high concentration nuclides in the subsequent solid-liquid separation process.

The above-described dissociative element separation method is not limited to the configuration and the method of the embodiments described above, but the embodiments may be configured such that all or some of the embodiments are selectively combined have.

Claims (10)

(a) injecting a spent fuel containing dissolved elements into a process salt to elute the dissolved source from the spent nuclear fuel;
(b) separating the solid phase and the liquid phase from each other while maintaining the spent nuclear fuel eluted and remaining in the solid phase and maintaining the process salt in which the dissolved source is dissolved in a liquid phase; And
(c) precipitating the dissolved source in the process salt,
The step (a)
(a1) injecting the spent nuclear fuel into a cathode basket to be used as a cathode of an electrolytic reduction process;
(a2) charging the cathode basket into a dissolved source separation device filled with a process salt; And
(a3) activating an agitator of the dissolved-organic separator to promote dissolution of the dissolved source from the spent nuclear fuel. delete The method according to claim 1,
Wherein the dissolved source separator comprises:
A reactor formed to receive the process salt;
A flange having a plurality of heat sinks to cover the reactor to limit heat loss of the process salt; And
And an agitator configured to promote dissolution of the dissolution source,
(A2), the holder connected to the cathode basket is inserted into the reactor through the flange, and the holder is mounted on the flange to immerse the cathode basket in the process salt. Method of separation of members. The method of claim 3,
Wherein the negative electrode basket is formed in a mesh shape so as to pass the liquid phase through the solid phase in the separating step (b). The method of claim 3,
The separating step (b) is performed while maintaining the temperature of the gas phase part formed between the interface of the liquid phase and the heat dissipation plate at a temperature higher than the melting point of the process salt, Wherein the negative electrode basket is stepwise lifted so as to expose the negative electrode on the interface of the liquid phase stepwise. 6. The method of claim 5,
Wherein the holder includes a plurality of pinholes arranged in a loading direction of the cathode basket,
Wherein the separating step repeats the step of lifting the negative electrode basket and inserting a fixing pin into a pinhole exposed on the flange and holding the pinhole for a predetermined period of time for each pinhole . 6. The method of claim 5,
Wherein when the negative electrode basket is completely exposed on the interface of the liquid phase, the negative electrode basket is handed over to the electrolytic reduction process. (a) injecting a spent fuel containing dissolved elements into a process salt to elute the dissolved source from the spent nuclear fuel;
(b) separating the solid phase and the liquid phase from each other while maintaining the spent nuclear fuel eluted and remaining in the solid phase and maintaining the process salt in which the dissolved source is dissolved in a liquid state; And
(c) precipitating the dissolved source in the process salt,
The step (c)
(c1) adding a phosphite capable of phosphorizing and precipitating the dissolved source to the liquid phase;
(c2) dispersing argon gas in the liquid phase to induce a reaction between the phosphide and the dissolved source; And
(c3) raising the temperature of the liquid phase, and then dispersing the oxygen gas to oxidize the dissolved source and precipitate in the process salt. A method for converting a spent fuel into a metal containing an electrolytic reduction process,
And a separation step of separating the dissolved source from the spent fuel at the previous stage of the electrolytic reduction step by causing an electrode damage in the electrolytic reduction process and concentrating the dissolved source in the process salt of the electrolytic reduction process,
The dissociative element separation method may further comprise:
(a) injecting a spent fuel containing dissolved elements into a process salt to elute the dissolved source from the spent nuclear fuel;
(b) separating the solid phase and the liquid phase from each other while maintaining the spent nuclear fuel eluted and remaining in the solid phase and maintaining the process salt in which the dissolved source is dissolved in a liquid phase; And
(c) precipitating the dissolved source in the process salt,
The step (a)
(a1) injecting the spent nuclear fuel into a cathode basket to be used as a cathode of an electrolytic reduction process;
(a2) charging the cathode basket into a dissolved source separation device filled with a process salt; And
(a3) activating an agitator of the dissolved-source separator to promote elution of the dissolved source fuel from the spent nuclear fuel. A method for converting a spent fuel into a metal containing an electrolytic reduction process,
And a separation step of separating the dissolved source from the spent fuel at the previous stage of the electrolytic reduction step by causing an electrode damage in the electrolytic reduction process and concentrating the dissolved source in the process salt of the electrolytic reduction process,
The dissociative element separation method may further comprise:
(a) injecting a spent fuel containing dissolved elements into a process salt to elute the dissolved source from the spent nuclear fuel;
(b) separating the solid phase and the liquid phase from each other while maintaining the spent nuclear fuel eluted and remaining in the solid phase and maintaining the process salt in which the dissolved source is dissolved in a liquid phase; And
(c) precipitating the dissolved source in the process salt,
The step (c)
(c1) adding a phosphite capable of phosphorizing and precipitating the dissolved source to the liquid phase;
(c2) dispersing argon gas in the liquid phase to induce a reaction between the phosphide and the dissolved source; And
(c3) raising the temperature of the liquid phase, and then dispersing the oxygen gas to oxidize the dissolved source and precipitate in the process salt.

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