JPH07120594A - Method and device for solidifying radioactive waste - Google Patents

Abstract

PURPOSE:To generate no waste washing liquor after a kneader is washed and prevent solidifying agent from hardening and adhering to a kneading vessel in a method and its device for solidifying radioactive waste. CONSTITUTION:After mixture paste of radioactive waste and a solidification agent is poured from a kneader 4 to a solidification vessel 6 at the time of cement-solidification of the radioactive waste, the inside of the kneader 4a is washed with addition water of a quantity for using ion a next batch and after its washing liquor is stored in a kneading vessel as it is agitated up to the next batch, it is used as kneading water of the next batch. A solidification delay agent may be added to the addition water in place of agitation or in addition thereto and the addition water may be circulated.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a nuclear facility (power plant,
The present invention relates to a method and an apparatus for kneading radioactive waste generated from a reprocessing plant), and particularly to a method and an apparatus for solidifying radioactive waste suitable for washing a kneader for kneading waste with a solidifying material such as cement.

[0002]

2. Description of the Related Art From nuclear facilities such as nuclear power plants, chemical waste liquid, solid waste, used ion-exchange resin, radioactive waste such as incineration ash are generated. These wastes are appropriately volume-reduced, then solidified in a solidified steel container using a solidifying material such as cement or plastic, and then buried and stored in a storage facility constructed underground. .

Particularly in the solidification treatment using a cement-based hydraulic solidifying material, it is necessary to uniformly knead the solidifying material, the added water and the waste. At this time, in order to improve the homogeneity of the mixed paste, a method of preparing a mixed paste using a dedicated kneader and pouring the mixed paste into a solidifying container to solidify, that is, an outdrum system is generally used. In the case of the outdrum system, in order to prevent the cement paste adhering to the kneading tank of the kneading machine, the kneading blades, the valve and the pipe for discharging the paste from adhering, the inside of the kneading machine is washed every batch or after the end of operation for one day. It is necessary to do.

In the conventional general cleaning method for a kneading machine, the cleaning waste liquid washed with water is directly treated as a secondary waste.

Further, as described in JP-A-60-3597, after the kneading paste is discharged, the kneading tank is filled with the washing water and the kneading blade is rotated to wash off the adhering cement paste or kneading the washing water. A method of spraying and cleaning the inside of the tank is also known. In this cleaning method, in a kneader that mixes radioactive waste, the cleaning waste liquid after cleaning also becomes radioactive waste, so this cleaning waste liquid is stored in a dedicated waste liquid storage tank, and the supernatant liquid is reused as a cleaning liquid several times. After that, it is transferred to the existing radioactive liquid waste treatment system for treatment.

Further, in Japanese Patent Laid-Open No. 177499/1987, the cleaning waste liquid generated after the cement paste adhering to the inside of the kneading machine is washed off with cleaning water is reused as additive water or cleaning water in the next step. A treatment method for reducing the cleaning waste liquid as secondary waste has been proposed. In this conventional technology, as one example thereof, after the solidifying material paste was dispensed, the amount of water used for the additive water of the next batch was supplied to the kneader from the wash water tank, and the stirring blade was rotated for a predetermined time to stir the mixture. After washing, the waste liquid after washing is left as it is in the kneading tank and used as added water in the next step.

[0007]

Among the above-mentioned conventional techniques, the method of treating the washing waste liquid washed with water as the secondary waste as it is has a problem that a large amount of radioactive liquid waste is generated.

Further, according to the prior art disclosed in Japanese Patent Laid-Open No. 60-3597, in the storage tank for the cleaning waste liquid, the cement particles contained in the cleaning waste liquid settle and harden at the bottom of the tank, and are deposited so that they can be treated. There is a risk of doing it. Further, since auxiliary equipment such as a storage tank for cleaning waste liquid and a transfer equipment for waste liquid is required, there is a problem that the equipment capacity becomes large and the equipment cost also increases.

In the prior art disclosed in Japanese Patent Laid-Open No. 62-177499, the cleaning waste liquid after stirring and cleaning by rotating the stirring blade for a predetermined time is left as it is in the kneading tank.
There was a possibility that the cement particles in the cleaning waste liquid settled, hardened, and adhered to the bottom of the kneading tank before the next step. This becomes a problem especially from the end of the work on one day to the start of the work on the next day, and when cement hardens or adheres, troubles such as blockage of the kneading machine may occur.

It is an object of the present invention to provide a method and apparatus for solidifying radioactive waste, which eliminates the generation of cleaning waste liquid after cleaning the kneading machine and does not cure or adhere the solidifying material in the kneading tank.

[0011]

The method for solidifying radioactive waste according to the first concept of the present invention employs the following constitution in order to achieve the above object. That is, a waste, a hydraulic solidifying material and added water are charged into a kneader to create a mixed paste, which is injected into a solidification container to be solidified, and the solidification method of the radioactive waste, the waste in the kneader, Solidification material,
After pouring out the mixed paste of the added water into the solidification container and feeding it out, the amount of added water to be used in the next batch is supplied to the kneading machine, the stirring blade is rotated to stir and wash the inside of the kneading machine, and then until the next batch. During this period, the added water is stored in the kneading tank while continuing the stirring by the rotation of the stirring blade, and the added water is used as the kneading water in the next batch.

In the above solidification method, preferably, after the mixed paste in the kneading machine is discharged, a predetermined amount of a curing retarder for delaying the hardening reaction of the solidifying material is supplied to the kneading machine together with an amount of added water used for the next batch. To do.

Further, preferably, after washing the inside of the kneader with stirring, until the waste and the solidifying material of the next batch are charged, the added water is circulated in a route branching from the discharge system of the kneader and returning to the kneader. Let

Agitation during the storage of the added water may be performed intermittently.

Further, preferably, the added water is supplied while the solidifying material paste adhering to the kneading tank is washed by spraying the amount of the added water used in the next batch into the kneading tank from the upper part of the kneading machine.

[0016] Further, preferably, stirring during washing in the kneading machine is performed at a higher rotation speed of the stirring blade than during normal operation, and stirring during addition water storage is about the same as or less than during normal operation. Reduce the rotation speed.

The method for solidifying radioactive waste according to the second concept of the present invention is configured as follows to achieve the above object. That is, a waste, a hydraulic solidifying material and added water are charged into a kneader to create a mixed paste, which is injected into a solidification container to be solidified, and the solidification method of the radioactive waste, the waste in the kneader, After the solidifying material and the mixed paste of the added water are poured into the solidifying container and discharged, a predetermined amount of the curing retarder that delays the hardening reaction of the added water and the solidifying material of the amount to be used in the next batch is supplied to the kneader. The stirring blade is rotated to stir and wash the inside of the kneader, and then, until the next batch, the mixed liquid of the added water and the curing retarder is stored in the kneading tank, and the mixed liquid is used as the kneading water in the next batch. .

Also in this case, it is preferable to add water in a route branching from the discharge system of the kneading machine and returning to the kneading machine until the waste and the solidifying material of the next batch are charged after washing the inside of the kneading machine with stirring. And circulating a mixture of the set retarder.

Further, preferably, the amount of added water used in the next batch is sprayed into the kneading tank from the upper part of the kneading machine to supply the adding water while washing the solidifying material paste adhering to the kneading tank.

Further, preferably, the stirring speed at the time of washing the inside of the kneading machine is higher than that at the time of normal operation.

Further, the method for solidifying radioactive waste according to the third concept of the present invention adopts the following constitution in order to achieve the above object. That is, waste, hydraulic solidifying material and added water are charged into a kneader to prepare a mixed paste,
In the method of solidifying radioactive waste by injecting this into a solidification container and solidifying, the waste in the kneading machine, the solidifying material, and the mixed paste of the added water are poured into the solidification container and discharged, after which the amount of the amount used for the next batch is The additive water is supplied to the kneader, and then, until the next batch, the additive water is circulated in the route branching from the discharge system of the kneader and returning to the kneader, and this added water is sprayed from the upper part of the kneader into the kneading tank. Then, in the next batch, the added water is used as kneading water.

In the above solidification method, preferably, the stirring blade is rotated during circulation of the added water to stir the added water in the kneader.

Further, preferably, after the mixed paste in the kneading machine is discharged, a predetermined amount of a hardening retarder for delaying the hardening reaction of the solidifying material is supplied to the kneading machine together with an amount of added water to be used in the next batch.

Further, the method for solidifying radioactive waste according to the fourth concept of the present invention adopts the following constitution similar to the first concept in order to achieve the above object. That is, the waste liquid and the hydraulic solidifying material are put into a kneading machine to prepare a mixed paste, which is poured into a solidifying container to be solidified, and in the method of solidifying radioactive waste, the mixed paste of the waste liquid and the solidifying material in the kneading machine is used. After pouring into the solidification container and discharging, the amount of waste liquid to be processed in the next batch is supplied to the kneading machine, the stirring blade is rotated to stir and wash the inside of the kneading machine, and then the stirring blade is rotated until the next batch. The waste liquid is stored in the kneading tank while continuing the stirring by, and the waste liquid is kneaded in the next batch.

In the above solidifying method, preferably, after the mixed paste in the kneading machine is discharged, a predetermined amount of a curing retarder for delaying the hardening reaction of the solidifying material is supplied to the kneading machine together with an amount of waste liquid to be processed in the next batch. .

Further, the method for solidifying radioactive waste according to the fifth concept of the present invention adopts the following constitution similar to the fifth concept in order to achieve the above object. That is, the waste liquid and the hydraulic solidifying material are put into a kneading machine to prepare a mixed paste, which is poured into a solidifying container to be solidified, and in the method of solidifying radioactive waste, the mixed paste of the waste liquid and the solidifying material in the kneading machine is used. After injecting into the solidification container and discharging, a predetermined amount of the curing retarder that delays the curing reaction of the waste liquid and the solidifying material to be processed in the next batch is supplied to the kneading machine, and the stirring blade is rotated to move the inside of the kneading machine. After stirring and washing, and then until the next batch, the mixed liquid of the waste liquid and the curing retarder is stored in the kneading tank,
The waste liquid is kneaded in the next batch.

Further, the method for solidifying radioactive waste according to the sixth concept of the present invention adopts the following constitution in order to achieve the above object. That is, waste, hydraulic solidifying material and added water are charged into a kneader to prepare a mixed paste,
In the method of solidifying radioactive waste by injecting this into a solidification container and solidifying, after mixing the waste in the kneading machine, the solidifying material, and the mixed paste of the added water into the solidifying container and discharging it, hardening of the added water and the solidified material A curing retardant that delays the reaction is supplied to the kneader, and the stirring blade is rotated to stir and wash the inside of the kneader,
Then, until the next batch, the mixture of the added water and the curing retarder is stored in the kneading tank while continuing the stirring by the rotation of the stirring blade, and the mixture is discharged to a dedicated tank before the start of the next batch. , Further return the supernatant liquid to the kneader in the dedicated tank and use it as kneading water or washing water for the next batch,
The precipitate is discharged into a solidification container and solidified.

Further, the method for solidifying radioactive waste according to the seventh concept of the present invention adopts the following constitution similar to the sixth concept in order to achieve the above object. That is, the waste liquid and the hydraulic solidifying material are put into a kneading machine to prepare a mixed paste, which is poured into a solidifying container to be solidified, and in the method of solidifying radioactive waste, the mixed paste of the waste liquid and the solidifying material in the kneading machine is used. Was poured into a solidification container and discharged, and a cleaning retardant was added to the kneading machine to delay the curing reaction between the cleaning water and the solidifying material, and the stirring blade was rotated to stir and wash the inside of the kneading machine.
Next, until the next batch, while stirring by rotating the stirring blade is continued, the mixed solution of the cleaning water and the curing retarder is stored in the kneading tank, and the mixed solution is discharged to a dedicated tank before the start of the next batch. Further, the supernatant liquid is returned to the kneading machine in the dedicated tank and used as washing water for the next batch, and the precipitate is discharged into a solidification container and solidified.

In the above solidification method, stirring may be carried out intermittently during storage of the mixed liquid of the additive water or the wash water and the curing retardant.

Further, preferably, stirring during washing in the kneading machine is performed by rotating the stirring blade at a higher speed than during normal operation, and stirring during storage of a mixed solution of added water or cleaning water and a curing retarder is performed during normal operation. Lower the rotation speed of the stirring blade to about the same as or less than the time.

Further, in the above solidification method, the curing retarder used is an oxycarboxylic acid, a dicarboxylic acid, a lower fatty acid, a sugar alcohol, a saccharide, a lignin sulfonic acid, a polyphosphate salt, or a derivative thereof, and a main component thereof. It is one selected from the complex.

Further, the apparatus for solidifying radioactive waste according to the first concept of the present invention adopts the following constitution in order to achieve the above object. That is, waste, a hydraulic solidifying material and added water or waste liquid and a hydraulic solidifying material are put into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified and a radioactive waste solidifying device. In the above, there is installed a system for supplying a predetermined amount of a curing retardant that delays the curing reaction of the solidifying material to the kneader.

In the above solidifying device, preferably, a nozzle for spraying the waste liquid into the kneading tank is installed above the kneading tank of the kneading machine.

Further, preferably, a circulation line branched from the discharge system of the kneading machine and returning to the kneading machine, and a circulation pump located in this circulation line are installed.

Further, the apparatus for solidifying radioactive waste according to the second concept of the present invention adopts the following constitution in order to achieve the above object. That is, waste, a hydraulic solidifying material and added water or waste liquid and a hydraulic solidifying material are put into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified and a radioactive waste solidifying device. In, a circulation line that branches from the discharge system of the kneading machine and returns to the kneading machine, and a circulation pump that is located in this circulation line are installed.

Further, the apparatus for solidifying radioactive waste according to the third concept of the present invention adopts the following constitution in order to achieve the above-mentioned object, that is, the waste, the hydraulic solidifying material and the added water. Alternatively, a waste liquid and a hydraulic solidifying material are put into a kneading machine to prepare a mixed paste, which is poured into a solidifying container and solidified in a solidification device for radioactive waste, and a predetermined amount of the hardening reaction of the solidifying material is delayed. System for supplying the curing retarder to the kneader, dedicated tank for receiving the cleaning waste liquid discharged from the kneader, system for returning the supernatant liquid in the dedicated tank to the kneader, means for discharging the precipitate in the dedicated tank to the solidification container Set up.

[0037]

In the method for solidifying radioactive waste according to the first to fifth concepts of the present invention, the amount of added water used in the next batch or the amount of waste liquid used in the next batch is used for cleaning the kneading tank. By using as the kneading water for the next batch, generation of new radioactive cleaning waste liquid is completely eliminated.

In the method for solidifying radioactive waste according to the first and fourth concepts of the present invention, by storing the additive water or the waste liquid in the kneading tank until the next batch, the dry cement of the residual cement in the kneading tank is prevented. To be prevented. Further, by rotating the stirring blade to stir the added water or the waste liquid, the cleaning effect in the kneading tank can be enhanced. Furthermore, while preventing the sedimentation of residual cement by stirring the added water or waste liquid, acting shear stress between the cement particles, delaying the hydration reaction of cement, hardening of the residual cement in the kneading tank, Adhesion is prevented, which prevents troubles such as clogging of the kneading machine.

In the method of solidifying radioactive waste according to the second and fifth concepts of the present invention, by storing the additive water or the waste liquid in the kneading tank until the next batch, the dry cement of the residual cement in the kneading tank is prevented. Will be prevented. In addition, the set retarder electrostatically adsorbs on the surface of the cement particles and temporarily blocks the reaction between the cement and water, delaying the hydration reaction of the cement and hardening the residual cement in the kneading tank. Adhesion is prevented, which prevents troubles such as blockage of the kneading machine.

In the method of solidifying radioactive waste according to the third concept of the present invention, the mixed paste adhering to the inside of the kneading tank or the stirring blade is dispersed by circulating the added water until the next batch and spraying it into the kneading tank. While being washed, the dry cement of the residual cement in the kneading tank is prevented. In addition, by circulating the added water to prevent sedimentation of residual cement, shear stress acts between the cement particles,
By delaying the hydration reaction of cement, the residual cement is prevented from hardening and adhering in the kneading tank, thereby preventing troubles such as clogging of the kneading machine. Further, the inside of the pipe of the discharge system of the kneading machine and the inside of the valve body can be effectively cleaned, and troubles such as blockage of the pipe can be prevented. In addition, since it is not necessary to rotate the stirring blade for cleaning, the life of the kneader is extended.

In the method for solidifying radioactive waste according to the first and fourth concepts and the method for solidifying radioactive waste according to the third concept, the effect of the second and fifth concepts is added by using a curing retarder together. The effect of preventing the residual cement from hardening and adhering in the kneading tank increases.

In the method for solidifying radioactive waste according to the first and fourth concepts and the method for solidifying radioactive waste according to the second and fifth concepts, the action of the third concept is added by circulating the cleaning waste liquid, The cleaning effect and the effect of preventing residual cement from hardening and adhering in the kneading tank are increased. Also, the inside of the discharge system piping and valve body of the kneading machine can be effectively cleaned, and troubles such as blockage of the piping can be prevented.

In the method of solidifying radioactive waste according to the first to fifth concepts, spraying added water or waste liquid into the kneading tank and / or rotating the stirring blade at a higher rotation speed than in normal operation. Thereby, the mixed paste adhering to the inside of the kneading tank or the stirring blade is efficiently washed.

In the method for solidifying radioactive waste according to the sixth and seventh concepts of the present invention, additive water or washing water and a curing retarder are supplied to a kneader, stirred and washed, and then until the next batch. By storing the added water or the washing water while continuing the stirring, the kneading tank and the stirring blade are washed and the inside of the kneading tank for the residual cement is stored, similarly to the first, second, fourth and fifth concepts. It prevents hardening and adhesion of the kneading machine and prevents troubles such as clogging of the kneading machine. Further, by returning the supernatant liquid to the kneading machine and using it as kneading water or washing water for the next batch in a dedicated tank, generation of new radioactive washing waste liquid is eliminated or minimized. Further, in the dedicated tank, the cleaning waste liquid contains a hardening retarder, and the solid slurry as a precipitate is discharged into a solidification container and solidified, so that the solid slurry is hardened at the bottom of the tank and the special tank is closed. Such troubles are also prevented. Furthermore,
Since a dedicated additive water tank or wash water tank is used,
The amount of wash water can be set freely.

The method for solidifying radioactive waste according to the first and fourth concepts of the present invention can be carried out by a conventional solidifying device without providing any special auxiliary equipment.

The solidification method for radioactive wastes according to the second and fifth concepts of the present invention is carried out by the solidification apparatus according to the first concept in which a conventional retardation agent supply system is provided.

The solidification method for radioactive waste according to the third concept of the present invention is carried out by the solidification device according to the second concept in which a circulation line and a circulation pump are simply provided in the conventional solidification device.

The method for solidifying radioactive waste according to the sixth and seventh concepts of the present invention is a system for supplying a hardening retarder to a conventional solidifying device, a receiving tank for cleaning waste liquid, a system for returning a supernatant liquid to a kneader, and precipitation. It is carried out by the solidification device according to the third concept, which is simply provided with a means for discharging the substance into the solidification container.

[0049]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Some embodiments of the present invention will be described below with reference to the drawings.

First Embodiment First, a first embodiment of the present invention will be described with reference to FIG.
The present embodiment is an application of the present invention to a case where a used ion exchange resin (radioactive waste resin) generated from a nuclear power plant is solidified with cement.

In FIG. 1, the apparatus for solidifying radioactive waste resin of this embodiment has a kneading machine 4, which is composed of a kneading tank 4a, a kneading blade 4b, a motor 4c for rotating the kneading blade 4b, and the like. There is. A waste resin tank 1, a solidifying material tank 2, and an additive water tank 3 are connected to the kneading machine 4, and the supply systems of the waste resin tank 1, the solidifying material tank 2, and the additive water tank 3 have fixed screw feeders 1a, 2a, and The valve 3a is installed. A discharge valve 5 is installed in the discharge system of the kneading machine 4. Below the valve 5 is a solidification container 6 made of steel.
Are set, and the solidification container 6 can be transferred by the conveyor 7.

The resin slurry extracted from the waste resin storage tank (not shown) is dehydrated by a dehydrator (not shown) and then supplied to the waste resin tank 1. The solidification operation is performed by first driving the screw feeders 1a and 2a with a predetermined amount of waste resin, solidifying material, and added water for one batch,
The valve 3a is opened and the waste resin tank 1, the solidifying material tank 2 and the added water tank 3 are charged into the kneading machine 4. The following is a guideline for each input amount.

Waste resin 100 kg Solidifying material 140 kg Added water 60 kg In the kneading machine 4, the stirring blade 4b is rotated at a rotation speed of about 100 rpm for about 3 minutes to uniformly mix the waste resin, the solidifying material and the added water to form a paste. To do. Then, the valve 5 is opened and the prepared mixed paste is injected into the solidification container 6 made of steel, and one batch is completed. The solidified container 6 that has been injected is transferred by the conveyor 7 and the next solidified container is set.

In the kneading machine 4, after discharging the mixed paste of the waste, the solidifying material and the added water, the valve 5 is closed and the valve 3a is opened to add the amount of the added water to be used in the next batch.
That is, 60 kg of water is supplied to the kneading machine 4. At this time, the stirring blade is preferably rotated at a low speed of about 50 rpm. After the addition water is supplied, the stirring blade 4b is rotated at a higher rotation speed (up to 200 rpm) than that during normal operation for about 2 minutes to wash the mixed paste adhering to the inside of the kneading tank 4a and the stirring blade 4b.

Next, the rotation speed of the stirring blade 4b is reduced to the rotation speed during normal operation, and the added water is stored in the kneading tank while continuing stirring until the next batch.

By storing the added water in the kneading tank until the next batch, it is possible to prevent the residual cement from sticking to dryness in the kneading tank. Further, by rotating the stirring blade and stirring the added water, the cleaning effect in the kneading tank can be enhanced.
Furthermore, by stirring the added water, the sedimentation of residual cement is prevented and shear stress is applied between the cement particles to delay the hydration reaction of cement and prevent the residual cement from hardening and adhering in the kneading tank. can do.

At the start of the kneading operation for the next batch, the screw feeders 1a and 2a are driven to supply a predetermined amount of waste resin and solidifying material to the kneading machine 4, and the added water held in the kneading tank 4a is used as kneading water. Then, the next kneading operation is started. The following operations are repeated: kneading → discharging mixed paste → supplying additional water → washing with stirring → storage with stirring → supplying waste resin / solidifying material → kneading.
The above is the procedure of the operation during the steady work. The higher the rotation speed of the stirring blade during cleaning, the wider the cleaning area inside the kneading tank, and the higher the cleaning efficiency of the attached paste.

At the end of the work on the first day, the additive water for the first batch on the next day was supplied to the kneading machine, and after the above washing operation was performed, the rotation speed of the stirring blade was lowered to a low speed (up to 50 rpm), and the work on the next day was performed. Continue stirring until the beginning of. By this operation,
In the same manner as described above, it is possible to prevent the residual cement from drying and sticking in the kneading tank, enhance the cleaning effect in the kneading tank, and prevent the residual cement from hardening and adhering in the kneading tank.

The solidifying material in this embodiment is a hydraulic solidifying material, and corresponds to cement-based solidifying material such as Portland cement and blast furnace cement, and cement glass. In addition to waste resin, the waste of this embodiment can be applied to dry powder of incineration ash and chemical waste liquid, compression molding (pellets), and granules and powder of molten solid waste. is there. Further, the present embodiment can be applied when solidifying a liquid waste such as a chemical waste liquid. In that case, since the waste liquid itself becomes added water, it is not necessary to supply the added water.

The cleaning operation does not necessarily have to be carried out for each batch, and it is sufficiently effective to carry out the cleaning operation every day. In addition, the stirring when storing the added water may be performed intermittently.

According to this embodiment, since the auxiliary equipment for cleaning the kneading tank is not required, the capacity of the apparatus is small and the equipment cost is low. Further, there is an effect that no secondary waste such as cleaning waste liquid is generated. Further, since the cleaning waste liquid is stored while being stirred, it is possible to prevent the solidifying material remaining in the kneading tank from settling and hardening at the bottom of the kneading tank and preventing troubles such as blockage of the kneading machine. it can.

Second Embodiment A second embodiment of the present invention will be described with reference to FIG. The present embodiment is an application of the present invention to the case where a radioactive chemical waste liquid (recycled waste liquid of an ion exchange resin) generated from a nuclear power plant is solidified by cement. The main component of this waste liquid is sodium sulfate.

In FIG. 1, the apparatus for solidifying the radioactive waste liquid of this embodiment has a kneading machine 9, which is composed of a kneading tank 9a, a kneading blade 9b, a motor 9c for rotating the kneading blade 9b, and the like. . A solidifying material tank 8, a waste liquid storage tank 10, and a retarder tank 15 are connected to the kneading machine 9. The retarder tank 15 stores a drug (hardening retarder) that delays the hardening reaction (hydration reaction) of cement. The solidification material tank 8, the waste liquid storage tank 10, and the delay agent tank 15 are provided in the supply system with a metering screw feeder 8a and a valve 1, respectively.
1. The metering pump 16 is installed, and the discharge valve 12 is installed in the discharge system of the kneading machine 9. A solidification container 13 made of steel is set below the valve 12.
Can be transported by the conveyor 14.

This embodiment is different from the first embodiment in that it is not necessary to supply the added water because the water in the waste liquid plays a role of the added water. The procedure of the solidification process will be described below.

A predetermined amount of cement is supplied from the solidifying material tank 8 to the kneading machine 9 by driving the screw feeder 8a, and then the valve 11 is opened to inject a predetermined amount of waste liquid from the waste liquid storage tank 10 into the kneading machine. The following is a guideline for the amount of waste liquid and solidifying material (cement) added.

Cement 260 kg Waste liquid 100 kg Next, the stirring blade of the kneader is rotated at a rotation speed of about 100 rpm for about 3 minutes to uniformly mix the waste liquid and the solidifying material to form a paste. The valve 12 is opened and the prepared mixed paste is injected into the solidification container 13 made of steel, and one batch is completed. The solidified container in which the injection is completed is transferred by the conveyor 14 and the next solidified container is set.

After discharging the mixed paste of the waste liquid and the solidifying material, the valve 12 is closed, the screw feeder 8a is driven to supply a predetermined amount of the waste liquid of the next batch to the kneader 9, and the fixed amount pump 16 is used to remove the curing retarder. A fixed amount is injected into the kneading machine 9. The amount of retarder added is about 0.2 to 3% based on the weight of cement, and when oxycarboxylic acids are used, a concentration of 0.1% in the added water is sufficient. The added amount will be described in detail later. Also,
At this time, the stirring blade is preferably rotated at a low speed of about 50 rpm. After the injection of the curing retarder, the stirring blade is rotated at a higher rotation speed (up to 200 rpm) than in normal operation for about 2 minutes to wash the mixed paste adhering to the inside of the kneading tank and the stirring blade.

Next, the rotational speed of the stirring blade is reduced to the rotational speed during normal operation, and the mixed liquid of the waste liquid and the curing retarder is stored in the kneading tank while continuing stirring until the next batch.

By storing the waste liquid in the kneading tank until the next batch, it is possible to prevent the residual cement from drying and sticking in the kneading tank. Further, by rotating the stirring blade and stirring the waste liquid, the cleaning effect in the kneading tank can be enhanced. Further, by stirring the waste liquid, sedimentation of residual cement is prevented, and shear stress is applied between cement particles to delay the hydration reaction of cement. Further, the setting retarder electrostatically adsorbs on the surface of cement particles and temporarily blocks the reaction between the cement and water, thereby exhibiting the effect of delaying the hydration reaction of the cement. With these, it is possible to prevent the residual cement from hardening and adhering in the kneading tank.

At the start of the kneading operation for the next batch, the screw feeder 8a is driven to supply a predetermined amount of cement to the kneading machine 9, and the next kneading operation is started. The following operations are repeated: kneading → discharging mixed paste → supplying waste liquid → injecting delay agent → washing with stirring → storage with stirring → supplying cement → supplying kneading. The above is the procedure of the operation during the steady work. The higher the rotation speed of the stirring blade during cleaning, the wider the cleaning area inside the kneading tank, and the higher the cleaning efficiency of the attached paste.

At the end of the work on the first day, the waste liquid of the first batch on the next day and a predetermined amount of the curing retarder were supplied to the kneader, and after the above washing operation was performed, the rotation speed of the stirring blade was set to a low speed (up to 50 r).
pm) and continue stirring until the start of work the next day.
By this operation, similarly to the above, it is possible to prevent the dry cement of the residual cement in the kneading tank, enhance the cleaning effect in the kneading tank, and prevent the residual cement from hardening and adhering in the kneading tank. Particularly, when the kneading machine is stopped for a long period of time, it is effective to increase the injection amount of the curing retarder.

The liquid retarder containing oxycarboxylic acids as a main component is the most suitable as the retarder in the present embodiment, but in addition, lignin sulfonate, magnesium fluorosilicate,
It is possible to use polyphosphates, borates, sugars such as glucose and saccharose, sugar alcohols such as ethylene glycol, lower fatty acids such as caproic acid and butyric acid, and oxycarboxylic acids such as gluconic acid and tartaric acid.

FIG. 3 shows the relationship between the concentration of the retarder in water and the time until the residual cement adheres to the inner wall of the kneading tank (cannot be washed) when oxycarboxylic acids are used as the retarder and stirred. If the added water is stored in the kneading tank without adding the retarder and without stirring, the residual cement will be fixed within a few hours. However, when the added water is stored in the kneading tank with stirring without adding the retarder (in the case of the first embodiment), it can be seen that the residual cement does not adhere for about 24 hours. . The addition of a retarder significantly delays the time required for fixation,
For example, if the concentration of the retarder is 0.1%, it can be seen that the residual cement does not stick for 2 days, and it is found that the addition of the retarder is effective especially when the interval between batches becomes long. As described above, the time required for the residual cement to adhere is largely different depending on the concentration of the retarder. Therefore, the concentration of the curing retarder may be determined according to the interval of each batch.

It should be noted that even if the curing retarder is too much, it only takes time for the mixed paste to be hardened in the solidification container after being poured into the solidification container, and there is no problem because it will eventually cure. However, if the curing retarder is too much, the mixed paste will not solidify in the solidification container for a long period of time, and there will be restrictions on handling such as movement of the container during that time. It is preferable to determine the concentration of the curing retarder according to

When the waste liquid containing sodium sulfate as a main component is solidified with cement as in the present embodiment, since sodium sulfate has an action of promoting the hardening reaction of cement, the cement mixed paste is prevented from sticking in the kneading tank and washed. The use of retarders is effective to increase efficiency. In addition, since the cement paste containing sodium sulfate has the property of easily sticking to the kneading tank due to the 10-hydrated sodium sulfate, it is necessary to always put the waste liquid in the kneading tank and transfer the 10-water chloride. It is even more effective if the temperature is raised to 32 ° C. or higher.

The solidifying material in this embodiment is a hydraulic solidifying material, and corresponds to cement-based solidifying material such as Portland cement and blast furnace cement, and cement glass.

In this embodiment, the stirring and the hardening retarder are used together to prevent the hardening of the cement in the cleaning waste liquid storage, but the object can be achieved by using the hardening retarder alone. Also in this embodiment, the cleaning operation does not necessarily have to be carried out for each batch, and it is sufficiently effective to carry out the cleaning operation every day. In addition, the stirring when storing the added water may be performed intermittently.

According to this embodiment, the auxiliary equipment for cleaning the kneading tank is only the retarder tank and the injection system, and the increase in the equipment capacity is small. Further, there is an effect that no cleaning waste liquid, which is a secondary waste, is generated. Furthermore, since a curing retarder is used and the cleaning waste liquid is stored while being stirred, it is possible to prevent a phenomenon in which the solidifying material remaining in the kneading tank settles and hardens at the bottom of the kneading tank, and troubles such as clogging of the kneading machine occur. It can be prevented.

Third Embodiment A third embodiment of the present invention will be described with reference to FIG. In this embodiment, in order to enhance the cleaning effect in the kneading tank, the added water is pressurized when it is supplied and sprayed into the kneading tank.

In FIG. 4, the apparatus for solidifying radioactive waste liquid of this embodiment has a kneading machine 16, and the kneading machine 16 is a kneading tank 16.
a, a kneading blade 16b, a motor 1 for rotating the kneading blade 16b
6c, which is installed in the upper part of the kneading tank 16a and is composed of a nozzle 24 and the like for spraying the added water toward the wall surface of the kneading tank and the stirring blades. Further, the kneading machine 16 is connected to a waste tank 17, a solidifying material tank 18, an added water tank 19, and a delay agent tank 22. Metering screw feeders 17a and 18a are installed in the supply systems of the waste tank 17 and the solidifying material tank 18, respectively, and a valve 20 and a metering pump 21 are installed in the supply system of the additive water tank 19 and a delay agent tank 22 is supplied. A metering pump 23 is installed in the system. The supply system of the additive water tank 19 is connected to the nozzle 24. The supply system of the delay agent tank 22 is the valve 20.
And the metering pump 21 are connected to the supply system of the additive water tank 19, and in this case, the additive water injected with the retarder is sprayed, so that the cleaning efficiency is further improved. The supply system of the retarder tank 22 may be directly connected to the kneader 16.
A discharge valve 25 is installed in the discharge system of the kneading machine 16, and a solidification container 26 made of steel is set below the valve 25, and the solidification container 26 can be transferred by a conveyor 26A.

Next, the operation procedure will be described mainly focusing on the cleaning operation. After uniformly kneading the waste, solidifying material and added water,
The mixed paste is put into the solidification container 26 through the valve 25 at the bottom of the kneading machine, and the kneading operation is completed. Then valve 2
5 is closed, the pressurizing pump 21 for the added water is started, and the valve 2
0, open the nozzle 2 with the amount of added water to be used in the next batch.
4 is sprayed into the kneading tank. At this time, the delay agent metering pump 23 is also activated to inject a predetermined amount of the delay agent into the added water. The amount of retarder added is about 0.2 to 3% based on the weight of cement, and when oxycarboxylic acids are used, a concentration of 0.1% in the added water is sufficient.
Moreover, it is desirable to rotate the stirring blade at a low speed of about 50 rpm. After spraying the added water, the stirring blade is rotated for several minutes at a higher rotation speed (up to 200 rpm) than during normal operation. By spraying the added water into the kneading tank and rotating the stirring blade at a higher rotation speed than in normal operation, the mixed paste adhering to the inside of the kneading tank and the stirring blade can be efficiently washed.

Next, the rotation speed of the stirring blade 16b is reduced to the rotation speed during normal operation, and the added water is stored in the kneading tank while continuing stirring until the next batch.

By storing the added water in the kneading tank until the next batch, it is possible to prevent dry cementing of residual cement in the kneading tank. Further, by rotating the stirring blade and stirring the added water, the cleaning effect in the kneading tank can be enhanced.
Further, by stirring the added water, sedimentation of the residual cement is prevented, and shear stress is applied between the cement particles to delay the hydration reaction of the cement. Further, the setting retarder electrostatically adsorbs on the surface of cement particles and temporarily blocks the reaction between the cement and water, thereby exhibiting the effect of delaying the hydration reaction of the cement. With these, it is possible to prevent the residual cement from hardening and adhering in the kneading tank.

At the start of the kneading operation for the next batch, waste resin,
A predetermined amount of the solidifying material is supplied to the kneading machine 16, and the added water retained in the kneading tank 16a is used as kneading water to start the next kneading operation. Hereafter, kneading → dispensing mixed paste → added water
Repeat the operations of delay agent spray supply → stirring cleaning → stirring storage → waste / solidifying material supply → kneading. The above is the procedure of the operation during the steady work. The higher the rotation speed of the stirring blade during cleaning, the wider the cleaning area inside the kneading tank, and the higher the cleaning efficiency of the attached paste.

At the end of the work on the first day, the additive water of the first batch on the next day and a predetermined amount of the curing retarder were spray-supplied to the kneader,
After performing the above washing operation, the rotation speed of the stirring blade is set to a low speed (~
50 rpm) and continue stirring until the start of work on the next day. By this operation, similarly to the above, it is possible to prevent the dry cement of the residual cement in the kneading tank, enhance the cleaning effect in the kneading tank, and prevent the residual cement from hardening and adhering in the kneading tank.

The solidifying material in this embodiment is a hydraulic solidifying material, and corresponds to cement-based solidifying material such as Portland cement and blast furnace cement, and cement glass. In addition to waste resin, the waste of this embodiment can be applied to dry powder of incineration ash and chemical waste liquid, compression molding (pellets), and granules and powder of molten solid waste. is there.

In this embodiment, the stirring and the hardening retarder are used in combination to prevent the hardening of the cement in the cleaning waste liquid storage, but the object can be achieved by only the hardening retarder or only the stirring. Also in this embodiment, the cleaning operation does not necessarily have to be carried out for each batch, and it is sufficiently effective to carry out the cleaning operation every day. In addition, the stirring when storing the added water may be performed intermittently.

According to the embodiment, it is possible to effectively clean the inside of the kneading tank without the need for a large-scale auxiliary equipment, and there is an effect that no radioactive cleaning waste liquid is generated. In addition, it is possible to prevent the solidifying material remaining in the kneading tank after washing from settling at the bottom of the kneading tank and hardening, and it is possible to prevent troubles such as clogging of the kneading machine.

Fourth Embodiment A fourth embodiment of the present invention will be described with reference to FIG. In this embodiment, by circulating the added water, not only the inside of the kneading tank but also the pipe for discharging the mixed paste and the inside of the valve body can be cleaned. This example is an optimum example for preventing cement from adhering to the inside of the kneading machine and the pipes and the valve body of the payout after the kneading work of one day is completed and before the work of the next day is started.

In FIG. 5, the apparatus for solidifying radioactive waste liquid of this embodiment has a kneader 27, and the kneader 27 is a kneading tank 27.
a, kneading blade 27b, motor 2 for rotating kneading blade 27b
7c and the like. The kneading machine 27 includes a waste tank 28, a solidifying material tank 29, an additive water tank 30,
The delay agent tank 32 is connected. Waste tank 2
8. The metering screw feeders 28a and 29a are installed in the supply system of the solidifying material tank 29, the valve 31 is installed in the supply system of the additive water tank 30, and the metering pump 33 is installed in the supply system of the retarder tank 32. is set up. Further, a three-way valve 34 is installed in the discharge system of the kneading machine 27, and the kneading machine 27 is branched from the three-way valve 34 as a circulation system of the added water.
A circulation line 36a returning to the above and a circulation pump 35 installed in this circulation line 36a are installed. Three-way valve 3
A steel solidification container 35 is set below 4,
The solidification container 35 can be transferred by the conveyor 35A.

Next, the operation procedure will be described mainly focusing on the cleaning operation. After uniformly kneading the waste, the solidifying material, and the added water, the mixed paste is put into the solidifying container 35 through the three-way valve 34 at the lower part of the kneading machine to complete the kneading operation. Then, the three-way valve 34 is fully closed, the valve 31 is opened, and the amount of added water used for the next batch is supplied into the kneading tank. At this time, the delay agent metering pump 33 is also activated to inject a predetermined amount of the delay agent into the added water. The amount of the retarder added is optimally about 1% based on the cement weight. At this time, it is desirable to rotate the stirring blade at a low speed of about 50 rpm. After the injection of the curing retarder, the stirring blade is rotated for a few minutes at a higher rotation speed (up to 200 rpm) than in normal operation to wash the mixed paste adhering to the inside of the kneading tank and the stirring blade.

Next, while rotating the stirring blade 27b at a low speed of about 50 rpm, the kneader 27 side of the three-way valve 34 and the circulation line 36a side are opened, and the circulation pump 35 is activated to add the added water in the kneading tank. Circulate. This operation is continuously performed until the next batch.

By circulating the added water through the kneading tank until the next batch, it is possible to prevent the residual cement from drying and sticking in the kneading tank. Further, by rotating the stirring blade and stirring the added water, the cleaning effect in the kneading tank can be enhanced. Further, by stirring the added water and circulating the added water, sedimentation of residual cement is prevented, and shear stress acts between cement particles to delay the hydration reaction of cement. Further, the setting retarder electrostatically adsorbs on the surface of cement particles and temporarily blocks the reaction between the cement and water, thereby exhibiting the effect of delaying the hydration reaction of the cement. With these, it is possible to prevent the residual cement from hardening and adhering in the kneading tank.

Furthermore, the effect of cleaning the inside of the pipe of the discharge system and the inside of the valve 34 by the operation of circulating the wash water through the discharge system is added, and the trouble of clogging of the pipe and the valve body due to the adherence of cement is avoided. be able to.

At the start of the kneading operation for the next batch, the three-way valve 3
4, the kneader 27 side is closed, the circulation line 36a side and the solidification container 35 side are opened, all the added water in the circulation line 36a is collected in the kneading tank, and the circulation pump 36 is stopped. next,
The rotation speed of the stirring blade 27b is set to the rotation speed during normal operation (100 r
pm), a predetermined amount of waste and solidifying material are supplied to the kneading machine 27, and the next kneading operation is started using the added water circulated in the kneading tank 27a as kneading water. Then, kneading → discharging mixed paste → supplying additional water → injecting retarder → washing by stirring → stirring ・
The operation of circulating storage → supplying waste / solidifying material → kneading is repeated. The above is the procedure of the operation during the steady work. The higher the rotation speed of the stirring blade during cleaning, the wider the cleaning area inside the kneading tank, and the higher the cleaning efficiency of the attached paste.

At the end of the work on the first day, the additive water of the first batch on the next day and a predetermined amount of the retarder were supplied to the kneader, and after the above washing operation was performed, the rotation speed of the stirring blade was set to a low speed (up to 50 rp).
m) and circulate the added water, and continue stirring and circulating until the start of work on the next day. By this operation, in the same manner as above, it is possible to prevent the dry fixation of the residual cement in the kneading tank, enhance the cleaning effect in the kneading tank, and prevent the hardening and adhesion of the residual cement in the kneading tank and the discharge system. You can

In this embodiment, the stirring, the hardening retarder and the circulation are used together to prevent the hardening of the cement during the storage of the cleaning waste liquid, but the object can be achieved only by circulating the added water. Also in this embodiment, the cleaning operation does not necessarily have to be carried out for each batch, and it is sufficiently effective to carry out the cleaning operation every day. In addition, the stirring when storing the added water may be performed intermittently.

According to this embodiment, the same effects as those of the previous embodiment can be obtained, and not only the inside of the kneading tank but also the discharge pipe of the cement paste and the inside of the valve body can be effectively cleaned. It is possible to prevent troubles such as blockage of the pipes.

A modification of this embodiment will be described with reference to FIG. In this example, the above-mentioned three-way valve 34 is provided in the discharge system of the kneader 27.
In place of the above, a normal valve 37 is installed, a joint 38 is provided at the tip of the pipe of the added water circulation line 36a, and the joint 38 is used to connect the tip of the pipe of the added water circulation line 36a to the discharge system of the kneader 27. Directly connect to the tip of the pipe and circulate the added water. At times other than the circulation of the added water, the joint 38 is disconnected and the connection is released. The other operations are the same as those in the fourth embodiment. The valve 37 may be the same as that used in the first to third embodiments, and a pinch valve, knife gate valve, sanders valve or the like can be applied.

This modification has the advantages that the three-way valve, which is complicated in operation, can be eliminated, and that all the piping of the cement paste discharge system can be cleaned.

The fourth embodiment and its modification are cases in which the radioactive waste is solid and additive water is used as kneading water. However, as in the second embodiment, the radioactive waste is a waste liquid. In this case as well, the ideas of these embodiments can be similarly applied.

Fifth Embodiment A fifth embodiment of the present invention will be described with reference to FIG. In this embodiment, the inside of the kneading tank can be cleaned by circulating the added water in the above-mentioned fourth embodiment.

In FIG. 7, the apparatus for solidifying radioactive waste liquid of this embodiment has a kneader 27A, and the kneader 27A is the kneading tank 2.
7a, the kneading blade 27b, a motor 27c for rotating the kneading blade 27b, and the like, and a nozzle 27d installed at the upper part of the inside of the kneading tank 27a for spraying circulated additive water toward the wall surface of the kneading tank or the stirring blade. I have it. The other structure is the same as that of the fourth embodiment shown in FIG.

Next, the operation procedure will be described mainly focusing on the cleaning operation. After uniformly kneading the waste, the solidifying material, and the added water, the mixed paste is put into the solidifying container 35 through the three-way valve 34 at the lower part of the kneading machine to complete the kneading operation. Then, the three-way valve 34 is fully closed, the valve 31 is opened, and the amount of added water used for the next batch is supplied into the kneading tank. At this time, the delay agent metering pump 33 is also activated to inject a predetermined amount of the delay agent into the added water. The amount of the retarder added is optimally about 1% based on the cement weight.

After the hardening retarder is injected, the kneader 27 side and the circulation line 36a side of the three-way valve 34 are opened, and the circulation pump 35 is opened.
Is started to circulate the added water in the kneading tank. This time,
The added water is sprayed into the kneading tank through the nozzle 27d. This operation is continuously performed until the next batch.

By circulating the additive water up to the next batch and spraying it into the kneading tank, the mixed paste adhering to the inside of the kneading tank and the stirring blades is washed and the residual cement is prevented from drying and sticking in the kneading tank. can do. Also,
The residual water is prevented from settling by circulating the added water, and shear stress is applied between the cement particles to delay the hydration reaction of the cement. Further, the setting retarder electrostatically adsorbs on the surface of cement particles and temporarily blocks the reaction between the cement and water, thereby exhibiting the effect of delaying the hydration reaction of the cement. With these, it is possible to prevent the residual cement from hardening and adhering in the kneading tank.

Furthermore, the effect of cleaning the inside of the pipe of the discharge system and the inside of the valve 34 by the operation of circulating the wash water through the discharge system is added, and the trouble of clogging of the pipe and the valve body due to the adherence of cement is avoided. be able to.

At the start of the kneading operation for the next batch, the three-way valve 3
4, the kneader 27 side is closed, the circulation line 36a side and the solidification container 35 side are opened, all the added water in the circulation line 36a is collected in the kneading tank, and the circulation pump 36 is stopped. next,
The stirring blade 27b is rotated at a rotation speed (100 rpm) during normal operation, a predetermined amount of waste and solidifying material are supplied to the kneader 27, and the added water circulated in the kneading tank 27a is used as kneading water for the next kneading. Start driving. The following operations are repeated: kneading → dispensing mixed paste → supplying additive water → injecting retardant → circulating spray cleaning / storage → supplying waste / solidifying material → kneading.

At the end of the work on the first day, the additive water for the first batch on the next day and a predetermined amount of the retarder were supplied to the kneader, and the additive water was circulated and sprayed as described above until the start of the operation on the next day. Continue circulation and atomization. By this operation, it is possible to prevent the residual cement from drying and sticking in the kneading tank while cleaning the inside of the kneading tank in the same manner as above, and to prevent the residual cement from hardening and adhering in the kneading tank and in the discharge system. .

In this embodiment, the curing retarder and the circulation of the added water were used together to prevent the cement from hardening during the storage of the cleaning waste liquid, but the objective can be achieved by only the circulation of the added water. Also in this embodiment, the cleaning operation does not necessarily have to be carried out for each batch, and it is sufficiently effective to carry out the cleaning operation every day. Further, this embodiment is
Although the radioactive waste is solid and the added water is used as the kneading water, the idea of this embodiment can be similarly applied to the case where the radioactive waste is a waste liquid as in the second embodiment. .

According to this embodiment, as in the fourth embodiment, not only the inside of the kneading tank but also the inside of the cement paste discharge system pipe and the inside of the valve body can be effectively washed, and the pipe is blocked. Trouble can be prevented in advance. Also, since it is not necessary to rotate the stirring blade for cleaning,
The life of the kneader can be extended.

Sixth Embodiment A sixth embodiment of the present invention will be described with reference to FIG. This example relates to a method for cleaning a kneading machine when a cleaning water tank is separately installed. As an example, a system for cementing a radioactive liquid waste concentrate (concentrated waste liquid) will be described.

In FIG. 8, the apparatus for solidifying radioactive waste liquid of this embodiment has a kneader 39, and the kneader 39 is a kneading tank 39.
a, kneading blade 39b, motor 3 for rotating kneading blade 39b
9c and the like. In addition, the kneading machine 39 includes a solidifying material tank 40, a concentrated waste liquid receiving tank 41, and a wash water tank 4.
2. The delay agent tank 45 is connected. A quantitative screw feeder 40a is installed in the supply system of the solidifying material tank 40, and valves 41a and 44 are provided in the supply systems of the concentrated waste liquid receiving tank 41, the wash water tank 42, and the retardant tank 45, respectively.
Also, a metering pump 33 is installed. Also, the kneading machine 3
The discharge system of 9 is provided with a discharge valve 43 and a movable (rotary) discharge pipe 47 whose position can be changed. The solidification container 4 made of steel is provided below one of the rotation positions of the discharge pipe 47.
4 is set, and the wash water storage tank 48 is provided below the other.
Is installed, and the valve 4 is installed at the bottom of the wash water storage tank 48.
9 is installed, and the solidification container 50 is set below the valve 49. The solidification containers 44 and 50 can be transferred by a conveyor (not shown).

A level meter 48a is provided in the wash water storage tank 48.
Is installed to detect both the liquid level of the supernatant liquid in the wash water storage tank 48 and the level of the precipitated solids. The wash water storage tank 48 is connected to the kneading tank 39a via a line 51a, and a supply pump 51 for returning the supernatant liquid in the wash water storage tank 48 to the kneader 39 is installed in the line 51a. .

The solidifying material and the concentrated waste liquid are supplied to the kneader 39 at a predetermined ratio and kneaded. The mixed paste after the kneading is injected into the solidification container 44 via the valve 43. At this stage, the outlet of the movable discharge pipe 47 is directed toward the solidification container 44 side. After closing the valve 43, the valve 44 is opened and the cleaning water is supplied from the cleaning water tank 42 until the kneading tank is filled to about 70%. At the same time, the delay agent is injected from the delay agent tank 45 into the kneading tank via the metering pump 46. The washing water is stored until the next batch while the stirring blade 39b is rotated. By this operation, as in the previous embodiment, the kneading tank and the stirring blades can be washed and the residual cement can be prevented from hardening and adhering in the kneading tank.

Before the start of the next batch, the outlet of the movable discharge pipe 47 is first directed to the wash water storage tank 48. Next, the valve 43 is opened, and the cleaning waste liquid in the kneading tank 39a is discharged to the cleaning water storage tank 48. The valve 43 is closed, the outlet of the movable discharge pipe 47 is directed to the solidification container 44 side, and the next kneading operation is started.

In the wash water storage tank 48, first, when the solid level reaches a level equivalent to the volume of the solidification container 50,
The valve 49 at the bottom of the tank is opened, and the solid slurry is discharged into the solidification container 50. The cement hardens in this discharge in about one month, and becomes a cement homogeneous solidified body. Further, when the supernatant liquid reaches a level of 50% or more, the supply pump 51 is operated at the time of cleaning the next batch to return it to the kneading tank 39a and reuse it as cleaning water. The cleaning water reused several times is mixed with the solidifying material to be solidified, and new cleaning water is supplied.

In the cleaning water storage tank 48, the cleaning waste liquid contains the curing retardant, and the solid slurry is discharged into the solidification container and solidified, so that the solid slurry as a precipitate is hardened at the bottom of the tank, It is possible to prevent a trouble such as the blockage of the wash water storage tank 48.

Also in the present embodiment, the cleaning operation does not necessarily have to be carried out for each batch, and it can be sufficiently effective to carry out the cleaning operation every day. In addition, the stirring when storing the added water may be performed intermittently.

According to the present embodiment, both the inside of the kneading machine and the mixed paste discharge system can be cleaned, and since the cleaning waste liquid is reused, no cleaning waste liquid is generated or the waste liquid is minimized. The load on the system can be reduced. Further, it is possible to prevent the solidifying material remaining in the kneading tank after washing from settling at the bottom of the kneading tank and hardening, and it is possible to prevent trouble such as blockage of the kneading machine. Similarly, in the wash water storage tank 48, the solid slurry is hardened at the bottom of the tank, and it is possible to prevent problems such as blockage of the tank. Furthermore, since a dedicated wash water tank is used, the amount of wash water can be set freely.

A modified example of this embodiment will be described with reference to FIG. In this example, the idea of the sixth example is applied to the solidification of solid radioactive waste. That is,
In this example, a waste tank 60 is arranged instead of the concentrated waste liquid receiving tank 41, and a quantitative screw feeder 60a is installed in the supply system of the waste tank 60. An addition / wash water tank 61 is arranged instead of the wash water tank 42. The other structure is the same as that of the sixth embodiment.

The operation procedure is the same as that of the sixth embodiment except that the water in the addition / washing water tank 61 is used as addition water in the kneading operation and is used as washing water in the washing operation.

According to this embodiment, the same effect as that of the sixth embodiment can be obtained in the washing operation when solidifying the radioactive waste.

[0124]

EFFECTS OF THE INVENTION According to the method for solidifying radioactive waste according to the first and fourth concepts of the present invention, it is possible to eliminate the generation of cleaning waste liquid accompanying the cleaning of the kneading machine without providing special incidental equipment. it can. Further, it is possible to prevent problems such as sticking and clogging of residual cement inside the kneader.

According to the method for solidifying radioactive waste according to the second, fifth and third concepts of the present invention, a small amount of auxiliary equipment can be used.
It is possible to eliminate the generation of cleaning waste liquid due to the cleaning of the kneading machine. Further, it is possible to prevent problems such as sticking and clogging of residual cement in the pipes and valve bodies of the mixed paste discharge system as well as in the kneader.

According to the solidification method for radioactive wastes according to the sixth and seventh concepts of the present invention, it is possible to eliminate the generation of cleaning waste liquid accompanying the cleaning of the kneader with a small amount of auxiliary equipment.
Further, it is possible to prevent problems such as sticking and clogging of residual cement in the pipes and valve bodies of the mixed paste discharge system as well as in the kneader. Further, it is possible to prevent the trouble that the dedicated tank is blocked, and it is possible to freely set the amount of washing water.

According to the apparatus for solidifying radioactive waste according to the first concept of the present invention, the method for solidifying radioactive waste according to the second and fifth concepts of the present invention can be implemented.

According to the apparatus for solidifying radioactive waste according to the second concept of the present invention, the method for solidifying radioactive waste according to the third concept of the present invention can be implemented.

According to the apparatus for solidifying radioactive waste according to the third concept of the present invention, the method for solidifying radioactive waste according to the sixth and seventh concepts of the present invention can be implemented.

[Brief description of drawings]

FIG. 1 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste resin according to a first embodiment of the present invention.

FIG. 2 is a schematic view of an apparatus for carrying out a method for solidifying a radioactive chemical waste liquid according to a second embodiment of the present invention.

FIG. 3 is a diagram showing a relationship between a concentration of a curing retarder and a time required for fixing residual cement.

FIG. 4 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste according to a third embodiment of the present invention.

FIG. 5 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste according to a fourth embodiment of the present invention.

FIG. 6 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste according to a modification of the fourth embodiment.

FIG. 7 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste according to a fifth embodiment of the present invention.

FIG. 8 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste according to a sixth embodiment of the present invention.

FIG. 9 is a schematic view of an apparatus for carrying out a method for solidifying radioactive waste according to a modification of the sixth embodiment.

[Explanation of symbols]

 1 Waste resin tank 2,8,18,29,40 Solidifying material tank 3,19,30 Added water tank 4,9,16,27,39 Kneader 5,12,25,37,43 Discharge valve (discharging system) 6,13,26,35,44,50 Solidification container 10 Waste liquid storage tank 15,22,35,45 Curing retarder tank 17,28,60 Waste tank 24,27d Nozzle 34 Three-way valve (exhaust system) 36 Circulation pump 36a Circulation line 41 Concentrated waste liquid receiving tank 42 Wash water tank 61 Addition / wash water tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Toshi Komori 7-2-1, Omika-cho, Hitachi-shi, Ibaraki Energy Research Laboratory, Hitachi Ltd. (72) Satoshi Hirayama 3-chome, 1-chome, Hitachi-shi, Ibaraki No. 1 Hitachi Ltd., Hitachi Plant (72) Inventor Tatsuo Izumida 3-1-1, Saiwaicho, Hitachi City, Ibaraki Hitachi Ltd., Hitachi Plant

Claims (26)

[Claims] 1. A method of solidifying radioactive waste in which waste, a hydraulic solidifying material and added water are charged into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified. After pouring the mixed paste of waste, solidifying material and added water into the solidifying container and discharging it, the amount of added water used for the next batch is supplied to the kneading machine, and the stirring blade is rotated to stir and wash the inside of the kneading machine. Then, until the next batch, the added water is stored in the kneading tank while continuing the stirring by the rotation of the stirring blade, and the added water is used as the kneading water in the next batch. Method. 2. The method for solidifying radioactive waste according to claim 1, after discharging the mixed paste in the kneader,
A method for solidifying radioactive waste, comprising supplying a kneading machine with a predetermined amount of a curing retarder that delays the curing reaction of the solidifying material together with an amount of added water used in the next batch. 3. The method of solidifying radioactive waste according to claim 1 or 2, wherein after the kneading machine is stirred and washed, the discharge system of the kneading machine is branched until the waste and the solidifying material of the next batch are charged. A method for solidifying radioactive waste, characterized in that added water is circulated through a route that returns to the kneader. 4. The method for solidifying radioactive waste according to claim 1, wherein stirring during addition water storage is performed intermittently. 5. The method for solidifying radioactive waste according to claim 1, wherein the amount of added water used for the next batch is sprayed into the kneading tank from the upper part of the kneading machine to remove the solidifying material paste adhering to the kneading tank. A method for solidifying radioactive waste, which comprises supplying additional water while washing. 6. The method of solidifying radioactive waste according to claim 1, wherein stirring during cleaning in the kneading machine is performed at a higher rotation speed of a stirring blade than during normal operation, and stirring during addition water storage is during normal operation. A method for solidifying radioactive waste, which is characterized by lowering the rotation speed of the stirring blade to about the same as or less than that. 7. A method of solidifying radioactive waste in which waste, a hydraulic solidifying material and added water are charged into a kneader to prepare a mixed paste, which is poured into a solidifying container to solidify. After pouring the mixed paste of waste, solidifying material, and additive water into the solidifying container and discharging it, the amount of the additive water used for the next batch and the predetermined amount of the curing retarder that delays the curing reaction of the solidifying material are put into the kneader. It is supplied, the stirring blade is rotated to stir and wash the inside of the kneading machine, and then, until the next batch, the mixed solution of the added water and the curing retarder is stored in the kneading tank, and the mixed solution is mixed in the next batch. A method for solidifying radioactive waste, characterized by being used as. 8. The method for solidifying radioactive waste according to claim 7, wherein the kneading machine is branched from the discharge system of the kneading machine after stirring and washing the inside of the kneading machine until the next batch of waste and the solidifying material are charged. A method for solidifying radioactive waste, which comprises circulating a mixed solution of added water and a curing retarder in a route returning to the kneading machine. 9. The method of solidifying radioactive waste according to claim 7, wherein the amount of added water used for the next batch is sprayed into the kneading tank from the top of the kneading machine to remove the solidifying material paste adhered in the kneading tank. A method for solidifying radioactive waste, which comprises supplying additional water while washing. 10. The method of solidifying radioactive waste according to claim 7, wherein stirring during cleaning in the kneading machine is performed by increasing the rotation speed of a stirring blade as compared with that during normal operation. 11. A method of solidifying radioactive waste in which waste, a hydraulic solidifying material and added water are charged into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified. After pouring the mixed paste of waste, solidifying material, and additive water into the solidifying container and discharging it, the amount of additive water used for the next batch is supplied to the kneader, and then the discharge system of the kneader until the next batch. Radioactive waste characterized in that the added water is circulated in the route branching from and returned to the kneading machine, and this added water is sprayed from the upper part of the kneading machine into the kneading tank, and the added water is used as kneading water in the next batch. How to solidify things. 12. The method for solidifying radioactive waste according to claim 11, wherein a stirring blade is rotated during circulation of the added water to stir the added water in the kneader. 13. The method of solidifying radioactive waste according to claim 11, wherein after the mixed paste in the kneading machine is discharged, a predetermined amount of curing is added together with an amount of added water to be used in the next batch to delay the curing reaction of the solidifying material. A method for solidifying radioactive waste, which comprises supplying a retarder to a kneader. 14. A method for solidifying radioactive waste in which a waste liquid and a hydraulic solidifying material are charged into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified, and the waste liquid and the solidifying material in the kneader are included. After pouring out the mixed paste of No. 1 into a solidification container and discharging it, the amount of waste liquid to be processed in the next batch is supplied to the kneading machine, the stirring blade is rotated to stir and wash the inside of the kneading machine, and then the mixture is stirred until the next batch. A method for solidifying radioactive waste, characterized in that waste liquid is stored in a kneading tank while continuing stirring by rotating blades, and the waste liquid is kneaded in the next batch. 15. The method for solidifying radioactive waste according to claim 14, wherein after the mixed paste in the kneading machine is discharged, a predetermined amount of curing delay is delayed together with the amount of the waste liquid to be processed in the next batch together with the curing reaction of the solidifying material. A method for solidifying radioactive waste, which comprises supplying the agent to a kneader. 16. A method of solidifying radioactive waste in which a waste liquid and a hydraulic solidifying material are charged into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified, and the waste liquid and the solidifying material in the kneader are included. After injecting the mixed paste into a solidification container and discharging it, a predetermined amount of a curing retarder that delays the curing reaction of the waste liquid and the solidifying material to be processed in the next batch is supplied to the kneader, and the stirring blade is rotated. Solidification of radioactive waste characterized by stirring and washing the inside of the kneading machine, then storing the mixed liquid of the waste liquid and the curing retarder in the kneading tank until the next batch, and kneading the waste liquid in the next batch. Method. 17. A method of solidifying radioactive waste in which waste, a hydraulic solidifying material and added water are charged into a kneader to prepare a mixed paste, which is poured into a solidification container to solidify. After pouring the mixed paste of waste, solidifying material and added water into the solidifying container and discharging it, supply the hardening retarder that delays the hardening reaction of the added water and the solidifying material to the kneader, and rotate the stirring blade to knead The inside of the machine is washed with stirring, and then the mixture of the added water and the curing retarder is stored in the kneading tank while continuing the stirring by the rotation of the stirring blade until the next batch, and the mixture is mixed before the start of the next batch. Is discharged to a dedicated tank, and the supernatant is returned to the kneading machine in the dedicated tank to be used as kneading water or washing water for the next batch, and the precipitate is discharged to a solidification container for solidification and radioactive disposal. How to solidify things. 18. A method of solidifying radioactive waste in which a waste liquid and a hydraulic solidifying material are charged into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified, and the waste liquid and the solidifying material in the kneader are included. After pouring out the mixed paste of the above into the solidification container and discharging it, the curing water is supplied to the kneader to delay the hardening reaction of the washing water and the solidification material, and the stirring blade is rotated to stir and wash the inside of the kneader, and then the next. Until the batch, while stirring by rotating the stirring blade, the mixture of cleaning water and curing retarder is stored in the kneading tank, and the mixture is discharged to a dedicated tank before the start of the next batch. A method for solidifying radioactive waste, characterized in that the supernatant liquid is returned to the kneader in the dedicated tank and used as washing water for the next batch, and the precipitate is discharged into a solidification container and solidified. 19. The method of solidifying radioactive waste according to claim 17 or 18, wherein the mixing of the additive water or the wash water and the mixed solution of the curing retarder is intermittently performed during storage. How to solidify things. 20. The method for solidifying radioactive waste according to claim 17 or 18, wherein stirring during washing in the kneading machine is performed by increasing the rotation speed of the stirring blade as compared with during normal operation, and the added water or washing water and the curing retarder are added. A method for solidifying radioactive waste, characterized in that the stirring speed during storage of the mixed liquid with is reduced to about the same as or lower than the speed during normal operation. 21. Claims 2, 7, 13, 15, 16, 1
19. The method for solidifying radioactive waste according to any one of 7 and 18, wherein the curing retarder is an oxycarboxylic acid, a dicarboxylic acid, a lower fatty acid, a sugar alcohol, a saccharide, a ligninsulfonic acid, a polyphosphate, or a derivative thereof. And a method of solidifying radioactive waste, characterized in that it is one selected from a complex containing these as main components. 22. A radioactive waste in which waste, a hydraulic solidifying material and added water or waste liquid and a hydraulic solidifying material are put into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified. The solidification device for radioactive waste, wherein a system for supplying a predetermined amount of a curing retarder that delays the curing reaction of the solidifying material to the kneader is installed. 23. The radioactive waste solidifying apparatus according to claim 22, wherein a nozzle for spraying the waste liquid into the kneading tank is installed above the kneading tank of the kneading machine. A solidification device for things. 24. The apparatus for solidifying radioactive waste according to claim 22, wherein a circulation line branched from the discharge system of the kneading machine and returning to the kneading machine, and a circulation pump located in this circulation line are installed. Equipment for solidifying radioactive waste. 25. A radioactive waste in which waste, a hydraulic solidifying material and added water or waste liquid and a hydraulic solidifying material are put into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified. In the solidification device of No. 1, a solidification device for radioactive waste, characterized in that a circulation line branched from the discharge system of the kneader to return to the kneader and a circulation pump located in this circulation line are installed. 26. A radioactive waste in which waste, a hydraulic solidifying material and added water or waste liquid and a hydraulic solidifying material are put into a kneader to prepare a mixed paste, which is poured into a solidifying container to be solidified. In the solidification device, a system that supplies a predetermined amount of a curing retarder that delays the curing reaction of the solidifying material to the kneader, a dedicated tank for receiving the cleaning waste liquid discharged from the kneader, and the supernatant liquid in the dedicated tank to the kneader. A solidification device for radioactive waste, which is equipped with a return system and means for discharging the precipitate in a dedicated tank to a solidification container.