JPH083556B2 - Radioactive waste liquid treatment device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a radioactive liquid waste treatment apparatus for extracting and separating transuranic element from a waste liquid containing transuranic element (actinide element) generated in a nuclear fuel cycle. .

[Prior Art] When nuclear fuel is burned in a nuclear reactor facility, the nuclear fuel is exhausted to produce fission products and plutonium ²³⁹ P
u etc. occurs. The plutonium and the like are fission nuclides and can be reused as nuclear fuel by extracting and refining. Therefore, the spent nuclear fuel is reprocessed. This is called the nuclear fuel cycle, and radioactive waste liquid is generated in the process of reprocessing spent nuclear fuel. This radioactive liquid waste contains a long half-life transuranic element ( ²³⁷ N) other than ²³⁹ Pu.
p, ²⁴¹ Am, etc.) and fission products ( ⁹⁰ Sr, ⁹⁹ Tc, ¹³⁷ Cs, etc.)
It is included. For this reason, it is necessary to separate these nuclides and perform treatment according to the characteristics of the nuclide to improve the safety at the time of waste treatment and disposal, and to make effective use as a radioactive isotope resource. Transuranic elements are recovered.

Conventionally, the extraction agent (DHDECM
P: dihex-NN diethylcarbamoylmethylene phosphonate, TBP: tributylphosphonate, etc. are used. As a conventional transuranic element extraction method using an extractant, the extractant is put into a waste liquid and stirred, and only the transuranic element is taken into the extractant, and water and the extractant are first separated,
Next, a so-called liquid extraction method for separating the extractant and the transuranium element in the extractant is a so-called liquid extraction method, and a mixer settler or the like is used.

[Problems to be Solved by the Invention] However, in the above-mentioned conventional method, a large amount of extractant is required for stirring, and the extractant and water cannot be completely separated after stirring. However, the extractant is mixed with the separated water and extracted, and the loss of the extractant is large.

However, in the case of DHD ECMP, the extractant itself is about 1500 yen / g
It is very expensive, and if a large amount of waste liquid is to be treated, the treatment cost will be extremely high.

[Means for Solving the Problems] In view of the above circumstances, the present invention provides a radioactive waste liquid treatment apparatus that efficiently uses a small amount of extractant and has extremely small loss loss of the extractant. An ultrasonic bath that mixes an emulsifying liquid to make an emulsion, a stirring / extracting tank that stirs the extractant emulsified in the ultrasonic bath and the nuclear fuel processing waste liquid, and agitating in the stirring / extracting tank. The agitated mixed solution is fed through the feed line and the extractant-capturing tower filled with the porous material that adsorbs and captures the extractant, and the eluent that elutes the transuranium element from the extractant are the extractant-capture tower. An eluent tank for supplying the eluent, an element recovery liquid discharge line for recovering an eluent in which the transuranium element is eluted from the extractant in the extractant trap, and an extractant trapped in the extractant trap Solvent for A solvent tank for supplying the extractant to the extractant-capturing tower through a supply line, and a solvent in which the extractant is dissolved are fed from the extractant-captured tower to evaporate the solvent to separate and recover the extractant and extract the extractant. A solvent evaporator for returning to the ultrasonic tank, and a condenser for condensing the solvent from the solvent evaporator and returning it to the solvent tank are provided.

[Operation] By mixing and stirring the emulsified extractant and the waste liquid, the transuranic element in the waste liquid is extracted by the extractant, and further, the mixed liquid is passed through the extractant-capturing tower so that the extractant is porous. The transuranic element is separated from the waste liquid by being adsorbed and captured by the substance. Next, the transuranic element is eluted and extracted from the extractant by passing an eluent.
The extractant is dissolved in the solvent, taken out from the extractant trap tower, and then separated from the solvent, and the extractant and the solvent are respectively recovered and reused.

[Example] An example of the present invention will be described below with reference to the drawings.

An ultrasonic tank 1 is connected to an extractant supply line 2 and an emulsifying liquid (water) supply line 3 to the ultrasonic tank 1.

Reference numeral 4 denotes a stirring / extracting tank, a waste liquid supply line 5 is connected to the stirring / extracting tank 4, a line mixer 6 is provided in the middle of the waste liquid supply line 5, and a line mixer 6 of the waste liquid supply line 5 is provided. Delivery line 7 from the ultrasonic tank 1 on the upstream side
Connect. A delivery pump 8 is provided in the middle of the delivery line 7.

A feeding line 10 having a feeding pump 9 on the way connects the stirring / extracting tank 4 and the extractant capturing tower 11. The extractant capturing tower
No. 11 is filled with a non-polar ion-exchange resin porous material inside. Examples of the non-polar ion exchange resin include polystyrene-DVB resin and tetrafluoroethylene resin.

The extractant capturing tower 11 and the ultrasonic tank 1 are connected by an extractant circulating line 12, and the extractant desorbing solvent receiving tank 13, circulation pump 14, solvent evaporator from the extractant capturing tower 11 side to the circulating line 12.
15, the recovery extractant receiving tank 16 is provided in sequence. The solvent evaporator 15 is connected to a solvent tank 18 by a solvent circulation line 17, and a condenser 19 and a recovered solvent receiving tank 20 are connected to the solvent circulation line 17 from the evaporator 15 side.
To provide.

The solvent tank 18 and the extractant capturing tower 11 are provided with a solvent supply line 21.
Are connected via the feed pump 22. Further, an eluent tank 27 is connected to the extractant capturing tower 11 via a feed pump 23, and a treatment liquid discharge line 24 and an element recovery liquid discharge line 26 are also connected.

Reference numeral 26 denotes a drying line, and the exhaust gas from the extractant capturing tower 11 is guided to the condenser 15 and then exhausted.

 The operation will be described below.

An extractant and an emulsifying liquid (water) are stored in the ultrasonic tank 1 via an extractant replenishing line 2 and an emulsifying liquid supply line 3, respectively. In the ultrasonic tank 1, the extractant and water are mixed by the vibration of ultrasonic waves to be emulsified and become an emulsion.
By this emulsification, the extractant becomes fine particles and the surface area thereof is remarkably increased. The emulsified liquid is introduced into the waste liquid supply line 5 by the delivery pump 8, mixed with the emulsified liquid by the line mixer 6, and the mixed liquid is delivered to the stirring / extraction tank 4.

In the stirring / extracting tank 4, the emulsified liquid and the waste liquid are further stirred, that is, the fine particles of the extractant are contacted with the waste liquid, and the transuranic element in the waste liquid is extracted by the extractant.

After the extraction in the stirring / extracting tank 4, the mixed liquid is delivered to the extractant capturing tower 11 via the delivery line 10 by the delivery pump 9. The mixed liquid passes through the porous material layer in the extractant trap tower 11 and is discharged from the processing liquid discharge line 24 to a storage tank (not shown).
Sent to. During the process of porous passage of this mixed liquid, the extractant is adsorbed and captured in the porous material layer, and the treated liquid discharge line 24
The liquid discharged is fine particles of extractant (ie transuranic element)
Will have been removed.

Since the porous material is colored when it captures the extractant, if the extractant trap tower 11 is a transparent container, the trapped state of the extractant can be visually confirmed.

When the extractant capturing tower 11 captures the extractant in a saturated state, the delivery pump 9 stops the delivery of the mixed liquid, and the delivery pump
By 23, the eluent is inserted into the extractant trap tower 11. The eluent elutes the transuranium element extracted by the extractant and is sent from the element recovery liquid discharge line 25 to a transuranic element separation facility (not shown).

After the elution of the transuranium element with the eluent, only the extractant is trapped in the porous material, and this extractant is recovered by being thawed with an organic solvent such as acetone.

The supply pump 22 allows the solvent to pass through the extractant-capturing agent 11 from the solvent tank 18 to dissolve the extractant. The dissolution state of the extractant can be confirmed by the change in the color of the porous material. The solvent in which the extractant is dissolved is once the solvent for removing the extractant solvent
It is stored in 13 and is sent to the evaporator 15 with the flow rate controlled by the circulation pump 14.

In the evaporator 15, the solvent is evaporated and the vapor is condensed.
It is sent to 19, is liquefied in the condenser 19, is received in the recovered solvent receiving tank 20, and is further stored in the solvent tank 18 via the solvent circulation line 17.

The recovered extractant separated by the evaporator 15 is received by the receiving tank 16, and is further supplied to the ultrasonic tank 1 as required.

 The extractant and the solvent are recovered as described above.

When the extractant trapped in the porous material is removed by the solvent, the porous material is dried. This is performed by sending dry air from the drying line 26 for the porous material to evaporate and dry the solvent attached to the porous material. The drying air exhausted from the extractant trapping 11 or the like is guided to the condenser 19, and is removed after removing the vaporized solvent.

When the drying of the porous material is completed, the series of steps described above is repeated again to separate the transuranic element.

[Effects of the Invention] As described above, according to the present invention, since the extractant is emulsified and stirred with the waste liquid, the contact area between the extractant and the waste liquid is large, and the transuranic element in the waste liquid is effective with a small amount of the extractant. Can be extracted. In addition, the extractant is a system in which it is collected and circulated, and the loss is extremely small.

[Brief description of drawings]

The figure is a block diagram showing the concept of the present invention. 1 is an ultrasonic tank, 4 is a stirring / extracting tank, 10 is a feeding line, 11
Is an extractant capture tower, 12 is an extractant circulation line, 15 is a solvent evaporator, 17 is a solvent circulation line, 18 is a solvent tank, 19 is a condenser, 21
Is a solvent supply line, and 27 is a solvent liquid tank.

Claims (1)

[Claims] 1. An ultrasonic tank for mixing an extractant and an emulsifying liquid to form an emulsion, and a stirring / extracting tank for stirring the extractant emulsified in the ultrasonic tank and a nuclear fuel processing waste liquid. An extractant-capturing tower filled with a porous material for adsorbing and capturing the extractant, in which an agitated mixed solution stirred in the agitating / extracting tank is fed through a feed line, and a transuranium element is eluted from the extractant An eluent tank for supplying an eluent to the extractant-capturing tower, an element recovery liquid discharge line for recovering an eluent in which the transuranium element is eluted from the extractant in the extractant-capturing tower, and an extractant-capturing tower A solvent tank for supplying a solvent for dissolving the captured extractant to the extractant capturing tower through a solvent supply line, and a solvent in which the extractant is dissolved are sent from the extractant capturing tower to evaporate the solvent. At least separate the extractant and collect it And a solvent evaporator to return the extractant to the ultrasonic bath, the radioactive liquid waste treatment apparatus characterized by comprising a condenser back to the solvent tank allowed condense solvent from the solvent evaporator.