JPH0829594A - Solidification of radioactive waste - Google Patents

Abstract

PURPOSE:To achieve reduction of the treating cost and enhancement of the reliability simultaneously by solidifying various types of radioactive waste using a single facility. CONSTITUTION:Concentrated waste liquid 1, waste resin 3, and the like are kneaded by means of a kneader 10 along with a hydraulic hardener and filled in a drum can 23. Miscellaneous solids are previously filled in the drum can 23 and injected into the gap of the drum can using a hydraulic harclener paste produced by means of the kneader 10. Fluidity of the kneaded material or paste produced using the hydraulic hardener is regulated by controlling the supply of fluidizing agent from a fluidizing agent supply tank 17. Consequently, the solidification cost can be reduced while lessening the burden on the operator and the radioactive waste can be solidified soundly and stably.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for solidifying radioactive waste, and more particularly, to solidifying a wide variety of radioactive waste generated from nuclear power facilities such as a nuclear power plant safely with a single facility. The present invention relates to a method for solidifying radioactive waste suitable for disposal.

[0002]

2. Description of the Related Art A variety of radioactive wastes such as concentrated waste liquid, so-called sludge such as waste ion exchange resin, combustible miscellaneous solids and non-combustible miscellaneous solids are generated from a nuclear power plant. These radioactive wastes are solidified by an optimum method according to their physical properties. For example, for the treatment of concentrated waste liquid and sludge, a method of mixing these with cement and solidifying them (Japanese Patent Publication No. Sho 63-52359 and Japanese Patent Publication No. Sho 63-289500) is used. A method (Patent No. 1174650) of pelletizing and then solidifying is known. For combustible miscellaneous solids, a method of melting and solidifying the incinerated ash obtained after incineration
For non-combustible miscellaneous solids, a method of pressurizing at high pressure to reduce the volume and then injecting cement between the press lumps for solidification treatment (Japanese Patent Laid-Open No. 4-110799) is known. There is. By adopting such a radioactive waste treatment method, not only the volume of the radioactive waste can be reduced, but also a stable solidified body excellent in long-term durability can be obtained.

[0003]

As described above, the radioactive waste generated from the nuclear power plant is appropriately solidified according to its properties. However, the implementation of these solidification treatments requires various equipment depending on the radioactive waste. Therefore, in order to install each solidification processing device in a nuclear power plant according to a plurality of radioactive wastes to be processed, a wide installation place corresponding to it is required.

It is an object of the present invention to provide a method for solidifying radioactive waste, which can reduce the footprint to be occupied.

Another object of the present invention is to provide a method for solidifying radioactive waste, which can obtain a uniform solidified body.

Another object of the present invention is to provide a method for solidifying radioactive waste, in which the fluidity of the first and second kneaded products to obtain a uniform solidified product can be easily adjusted.

Another object of the present invention is to provide a method for solidifying radioactive waste, which can reduce the amount of secondary radioactive waste generated during solidification.

[0008]

The features of the invention of claim 1 for attaining the object of the present invention are obtained by kneading at least three substances of a hydraulic solidifying material, water and radioactive waste in a kneader. The first kneaded product is poured into a solidification container, and at least two materials, water-solidifying material and water, excluding radioactive waste are kneaded in the kneader, and the second kneaded product is filled with the radioactive waste in advance. It is to inject into the solidified container.

A third aspect of the present invention that achieves another object of the present invention is that the fluidity of the second kneaded product obtained by the kneading machine is the first kneaded product obtained by the kneading machine. It is higher than that.

A fourth aspect of the present invention that achieves another object of the present invention is that the second kneaded material obtained by the kneading machine contains a fluidizing agent, and the second kneading matter obtained by the kneading machine is the same. The first kneaded product contains the fluidizing agent in an amount smaller than that of the fluidizing agent contained in the second kneaded product.

A fifth aspect of the present invention which achieves another object of the present invention is that the second kneaded material obtained by the kneading machine contains a fluidizing agent, and the second kneading matter obtained by the kneading machine is The first kneaded product contains no fluidizing agent.

A feature of the invention of claim 6 which achieves another object of the present invention is that the fluidizing agent is an inorganic fluidizing agent or a surfactant-based fluidizing agent.

Another feature of the present invention for attaining another object of the present invention is that the first or second kneaded product in the kneading machine is injected into the solidifying container when the solidifying container is filled with the solidified container. Detecting the liquid level of the kneaded product, detecting the weight of the solidification container when this liquid level reaches a predetermined value, and based on the detected weight, the amount of the kneaded product remaining in the kneader. To ask.

[0014]

A first kneaded product obtained by kneading at least three substances of a hydraulic solidifying material, water and radioactive waste in a kneader, and at least two substances of hydraulic solidifying material and water excluding radioactive waste Since the second kneaded product obtained by kneading in the above kneader can be obtained in the same kneader, the radioactive solidification treatment equipment can be made compact. Therefore, the installation area occupied by the radioactive solidification treatment facility can be reduced.

Since the fluidity of the second kneaded material is higher than that of the first kneaded material, it is possible to satisfactorily penetrate between the radioactive wastes filled in the solidification container. For this reason, the solidified body obtained when the radioactive waste is filled in the solidification container in advance becomes uniform with very few voids. On the contrary, since the fluidity of the first kneaded material containing the radioactive waste is lower than that of the second kneaded material, it is possible to prevent the radioactive waste from being unevenly distributed in a part of the solidified body, particularly in the upper part or the lower part. A uniform solidified body can be obtained.

The second kneaded product contains a fluidizing agent, and
Since the kneaded material contains the fluidizing agent in an amount smaller than that of the fluidizing agent contained in the second kneaded material, the fluidity of them can be easily adjusted. If the amount of solidifying material is small, the strength of the solidified body will not reach the prescribed strength, and conversely if the amount of solidifying material is larger than the required amount, the filling amount of radioactive waste into the solidifying container will decrease, the so-called volume reduction ratio is poor. Become. Therefore, the amount of adjustment of the solidifying material is small, and it is difficult to adjust the fluidity of each of the first and second kneaded products. However, in the present invention, it is not necessary to adjust the fluidity by adjusting the mixture of the radioactive waste and the solidifying material, and the above fluidity can be easily adjusted.

Even if the second kneaded material contains the fluidizing agent and the first kneaded material does not contain the fluidizing agent, the fluidity thereof can be easily adjusted for the same reason.

When the solidification container is filled with the first or second kneaded product in the kneading machine, the liquid level of the kneaded product injected into the solidification container is detected, and the solidification container when the liquid level reaches a predetermined value. Is detected and the amount of the kneaded material remaining in the kneading machine is determined based on the detected weight, the amount of the kneaded material to be newly created can be determined in consideration of this residual amount. Therefore, the amount of secondary radioactive waste generated by the solidification treatment can be significantly reduced.

The inventors have realized that the kneading solidification and the injection solidification can be performed by a single solidifying equipment, so that the solidifying equipment can be made compact and the installation area occupied by the solidifying equipment can be reduced. The kneading and solidification is to knead the radioactive waste, the hydraulic solidifying material and water, and then fill the solidified container with the kneaded material to solidify. On the other hand,
The injection and solidification is to inject a kneaded product of a hydraulic solidifying material and water into a solidifying container filled with radioactive waste in advance to solidify.

By solidifying the radioactive waste with a hydraulic solidifying material such as cement, a solidified product having excellent long-term stability while ensuring volume reduction can be obtained. In solidification, so-called kneading and solidification is required for liquid or powdered concentrated waste liquid, waste sludge, incineration ash, etc., while so-called injection solidification is required for miscellaneous solids such as metal pipes. . Therefore, by enabling kneading solidification and injection solidification with a single facility, almost all radioactive waste generated from radioactive material handling facilities such as nuclear power plants can be solidified with a single facility. The installation area of the equipment is reduced and the load on the operator can be reduced.

The inventors have found that it is desirable to solve the following three problems in order to make the kneading solidification and the injection solidification by a single solidification treatment facility more preferable. In the following, details of the problems and examples of solutions will be described in detail.

The first problem is to secure the physical properties of the solidified body.
When injecting and solidifying miscellaneous solid waste such as metal pipes, it is necessary to infiltrate the solidification material into the gaps between the miscellaneous solid wastes, and therefore the solidification material is required to have high fluidity. On the other hand, in the case of kneading and solidification, it was found that although the solidifying material needs an appropriate fluidity, if the fluidity is too high, a uniform solidified product cannot be obtained. An example will be described below. When the waste resin with a specific gravity of about 1 (used ion exchange resin) is kneaded and solidified with cement, if the fluidity of the cement paste with a specific gravity of about 2 becomes extremely high, the waste resin floats above the solidified body due to the difference in specific gravity. However, a uniform solidified body cannot be obtained. As light-weight waste that causes similar problems,
There is also incinerated ash. Also, in the case of metal powder with a high specific gravity of around 5, if the fluidity of the cement paste is extremely high, the waste will settle below the solidified body, contrary to the waste resin, and a uniform solidified body will be obtained. Absent. The fluidity of the cement paste is preferably lower than a certain value in order to prevent such waste floating and sedimentation and to obtain a uniform solidified body. As described above, the inventors have concluded that it is desirable that the fluidity of the cement paste is high in injection solidification and low in kneading solidification. However, since the fluidity of the cement paste is changed, it is complicated and impractical to adjust the composition of the cement according to the radioactive waste.
The inventors have added a suitable fluidizing agent to cement paste or the like in the case of injection solidification and adding a fluidizing agent in the case of kneading and solidification without changing the composition of cement according to radioactive waste. By not using or reducing the amount added,
It was found that a uniform and sound solidified body can be created for all radioactive wastes. As the fluidizing agent here,
Fly ash or silica fume (these are called inorganic superplasticizers) that are spherical fine powder and have a bearing effect,
There are high-condensation products of calcium lignin sulfonate and formaldehyde naphthalene sulfonate, which are generally called water reducing agents in the family of surfactants. Further, in order to realize such fluidity adjustment in terms of equipment, a fluidizer supply tank may be connected to the kneading machine.

The second problem relates to the control of the amount of cement paste filled in the solidification container. Conventionally, the radioactive waste to be solidified was limited, so the weight of the kneaded material to be filled in the solidification container (usually a 200-liter drum) is known in advance, and the waste to be kneaded at once with the kneader. It was also possible to easily calculate the composition of cement, water, etc. However, when attempting to solidify a wide variety of radioactive waste, the specific gravity of the kneaded material changes significantly, so the optimum values such as the total weight of radioactive waste, cement, water, etc. to be kneaded at one time should be calculated in advance. It is difficult to predict. That is, when the specific gravity of the radioactive waste is small, the specific gravity of the kneaded material also becomes small. Therefore, if the kneaded material of the same weight is created at one time and it is tried to fill the 200 liter drum, the volume of the kneaded material exceeds 200 liters. It may end up overflowing from the drum. On the contrary, when the specific gravity of the radioactive waste is large, the specific gravity of the kneaded product is also large, which may cause inefficiency such that the kneaded product is filled with less than half of the drum can volume.

Such a problem can be solved by monitoring both the liquid level and the weight in the solidification container when the kneaded product is transferred from the kneader to the solidification container. That is, in the present invention, radioactive waste, cement, water, etc. are kneaded by a kneader at a predetermined ratio, but the total weight thereof must be a roughly expected value. After completion of the kneading, the kneaded product is filled in a drum, but the liquid level is monitored so that the kneaded product does not overflow from the solidification container. When the liquid level reaches a predetermined value, the filling of the kneaded material is stopped, and at the same time, the amount of the kneaded material remaining in the kneading machine is obtained from the increase in the weight of the drum that is being monitored. In the next kneading operation, the amount of the remaining kneaded material is taken into consideration to determine the amount of waste and cement that should be newly added, so that excessive residue does not remain in the kneader (this residue is the final It becomes secondary waste), and it becomes possible to operate the solidification device. In this way, by monitoring both the liquid level and the weight in the solidification container, it is possible to prevent the kneaded material from overflowing from the solidification container even when solidifying a large number of wastes, and also to prevent secondary disposal. It is possible to minimize the amount of material generated.

The third problem is that when solidifying a large number of kinds of waste in a single facility, the setting of operating conditions becomes complicated. This can be solved by providing an operation control panel in which the required control amount is automatically set when the type of waste is specified. As a result, not only the load on the operator can be reduced, but also the reliability and safety during operation can be improved.

[0026]

Embodiments of the present invention will be described below.

(Embodiment 1) As one embodiment of the present invention, a radioactive waste solidification processing apparatus suitable for solidifying the radioactive waste generated from a boiling water nuclear power plant is shown in FIGS. 1 and 2.
Will be explained.

A concentrated waste liquid 1 containing Na ₂ SO ₄ as a main component is a concentrated waste liquid tank 2, a waste resin 3 containing a granular used ion-exchange resin as a main component is a sludge tank 4, and an incinerated ash 5 is an incinerated ash tank 6. , Stored separately. The concentrated waste liquid tank 2 is connected to the kneading machine 10 by a pipe 40 having a valve 7.
Connected to. The sludge tank 4 is connected to the kneader 10 by a pipe 41 having a valve 8. Dehydrator 1
1 is provided in the pipe 41 between the valve 8 and the kneader 10. The incineration ash tank 6 is connected to the kneading machine 10 by a pipe 42 having a valve 9.

Further, the solidifying material tank 15 in which the type C blast furnace cement, which is a hydraulic solidifying material, is filled is connected to the kneading machine 10 by a pipe 43. The valve 44, the measuring container 12, and the valve 45 are provided in this order on the pipe 43 from the solidifying material tank 15 side. The water tank 16 filled with water is connected to the kneading machine 10 by a pipe 46. The valve 47, the measuring container 13, and the valve 48 are provided in this order in the pipe 46 from the water tank 16 side. Further, a fluidizing agent supply tank 1 having a fluidizing agent filled therein
7 is connected to the kneading machine 10 by a pipe 49. The valve 50, the measuring container 14, and the valve 51 are provided in this order in the pipe 49 from the fluidizing agent supply tank 17 side. Although not shown, the weighing containers 12, 13, 14 have weighing scales. The weighing scale measures the weight of the substance filled in the weighing container. The measured value of the weight measured by these scales is input to the controller 52.

The detailed structure of the kneading machine 10 will be described with reference to the drawings. The kneading machine 10 is provided with a kneading blade 20 which is directly driven by a motor 19 inside an inverted conical casing 18. The motor 19 is provided above the casing 18. In addition, the knife gate valve 21 and the pinch valve 2
2 is connected to the lower part of the kneading machine 10. Knife gate valve 2
1 and the pinch valve 22 are each driven by a motor (not shown). The drum can 23 having an inner volume of about 200 liters, which is used as a solidification container, is set at the lower part of the kneading machine 10 through a miscellaneous solids supply area 24 as needed by using a transfer means such as a conveyor. There is.

Also, the valves 7, 8, 9, 44, 45, 4
The controller 52 controls the motors 7, 48, 50, 51, the motor 19, and the motors for driving the knife gate valve 21 and the pinch valve 22, respectively. The controller 52 stores, in its memory (not shown), the weights of the solidifying material, water, and the fluidizing agent to be mixed with the predetermined weight of each radioactive substance as shown in Table 1 as set values.

[0032]

[Table 1]

Although not shown, the operation panel 25 has a switch for selecting a radioactive material for solidifying, a start button and a stop button. The selection switch is a rotary switch and can select OFF, concentrated waste liquid, waste resin, incinerated ash, metal pipe, and the like. The operation panel 25 also has a display device (not shown).

The concentrated waste liquid, the waste resin and the incinerated ash are kneaded and solidified. A kneading and solidifying process using the solidifying device of this embodiment will be described by taking waste resin as an example.

The operator turns on the selection switch of the operation panel 25.
The state of FF was changed to waste resin, and then the start button was pressed. Before pressing the start button, all valves are closed. The controller 52 first opens the valve 8 in response to the start signal generated by pressing the start button. The waste resin 3 having a solid content concentration of about 5% in the sludge tank 4 is sent to the dehydrator 11. Here, the waste resin 3 is centrifugally dehydrated to a water content of about 50%.
Valve 8 when the amount of dehydrated waste resin reaches 100 kg
Is closed. This is because the measured value of the weight of the waste resin 3 measured by the weight scale provided in the dehydrator 11 is input to the controller 52, and when the set value 100 kg is reached, the controller 52 closes the valve 8.

The controller 52 selects the substance to be mixed with the waste resin based on the information of Table 1 stored in the memory and operates the corresponding valve. In this case, the substances to be mixed are solidifying material and water. Controller 52 opens valves 44 and 47. C class blast furnace cement in the measuring container 12,
And water is introduced into the measuring container 13. The value measured by the weight scale installed in each weighing container is 130 kg for the former and 5 for the latter.
When the weight reaches 5 kg, the controller 52 controls the valves 44 and 47.
Close. The closing of these valves is not simultaneous. Next, the controller 52 opens the valves 45 and 48 and drives the motor 19 of the kneading machine 10. The type C blast furnace cement and water supplied into the kneading machine 10 are kneaded by the rotation of the kneading blade 20. In this way, the solidifying material paste for kneading and solidification is prepared. Then, 100 kg of dehydrated waste resin obtained by the dehydrator 11 is put into the solidifying material paste in the kneader 10. Again, 5 with the kneading blade 20
Knead for minutes to obtain the final kneaded product. Even during this kneading, the motor 19 is controlled by the controller 52.
During this time, the knife gate valve 21 and the pinch valve 22 were closed, but upon receipt of a control signal from the controller 52 informing the end of kneading, the knife gate valve 21 and the pinch valve 22 each having a diameter of 15 cm are fully opened. As a result, all the kneaded material in the kneading machine 10 is discharged to the drum can 23. After that, the knife gate valve 21 and the pinch valve 22 are closed under the control of the controller 52. This completes the solidification processing work. However, in order to smoothly discharge the kneaded material, the kneading blade 2
The rotation of 0 continues. Further, although the viscosity of the kneaded material obtained by the kneading machine 10 is considerably high (about 100 poise), the diameter of the pipe including the knife gate valve 21 and the pinch valve 22 is as large as 15 cm, so the kneaded material is discharged. Occlusion or sticking does not occur. By such control, the information measured by the solidification processing device and the information created by the controller 52 are displayed on the display device of the operation panel 25.

A drum can 23 in which the kneaded material is sealed
Is sealed at the upper end with a lid by a drum can sealing device (not shown). The drum can 23 is transferred to a storage location. In addition to the waste resin 3 described above, the concentrated waste liquid 1 and the incinerated ash 5 can be similarly kneaded and solidified. The solidification treatment of the concentrated waste liquid 1 and the incinerated ash 5 is basically the same as the case of the waste resin, and therefore the description thereof is omitted. Also in this case, if the type of radioactive waste is designated on the operation panel 25, the amounts of waste, solidifying material, and water to be supplied to the kneading machine 10 are automatically determined, and the required valve opening / closing operation and kneading are performed. The blades are rotated to create a solid waste material. The mixing ratios of radioactive waste, solidifying material, and water shown in Table 1 are not necessarily fixed, but change depending on the type of solidifying material, the finally required physical properties of the solidified body, and the like.

In the above, the case where the radioactive waste is kneaded and solidified with the hydraulic solidifying material has been described. Next, injection solidification will be described by taking radioactive miscellaneous solid waste using the same radioactive solidification treatment device as an example.

In the miscellaneous solid supply area 24, the drum can 23 is filled with about 300 kg of metal pipes in advance. After that, the drum can 23 is transferred by a conveyor to the kneading machine 1.
It is set at the bottom of 0. In this state, the selection switch of the operation panel 25 is switched from waste resin to coarse solid, and the start button is pressed. Based on the stored information in Table 1, the controller 52 that has received this start signal inputs the valve 4
Open 4,47,50. The Class C blast furnace cement, water, and the water reducing agent (high-condensation product of naphthalenesulfonic acid formaldehyde) in the superplasticizer supply tank 17 are supplied to the corresponding measuring containers. The weighing scales provided in the weighing containers 12, 13, and 14 respectively transmit the measured weight values to the controller 52. When the measured value of each substance reaches the set value shown in Table 1, the controller 52 sets the corresponding valve 4
Close 5, 48 and 51 respectively. When these valves are closed, 170 kg of Class C blast furnace cement is present in the measuring container 12, 70 kg of water is present in the measuring container 13, and 1 kg of a water reducing agent which is a fluidizing agent is present in the measuring container 12. To do.

The controller 52 uses valves 45, 48, 5
When opening 1, these substances are fed into the kneader 10. The controller 52 drives the motor 19 at the same time when the valves 45, 48 and 51 are opened. These substances are kneaded by the kneading blade 20 for 3 minutes to form a solidifying material paste having a low viscosity of 5 poise and excellent fluidity. During this time, the knife gate valve 21 and the pinch valve 22 are closed.
After the completion of the kneading, the controller 52 fully opens the knife gate valve 21 and partially opens the pinch valve 22 having a diameter of 15 cm so that the flow passage area becomes 5 cm ² while the kneading blade 20 continues to rotate. As a result, the solidifying material paste in the kneading machine 10 is poured at a rate of about 20 kg / min into the drum can 23 that is filled with the metal pipe in advance. This drum can 2
3 is transferred to a storage location after being sealed by a lid. In this way, a solidified body of radioactive miscellaneous solids including metal pipes is produced. After the injection of the solidifying material paste, the knife gate valve 21 and the pinch valve 22 are connected to the controller 5
Closed by 2. At this point, the solidification work of the metal pipe is completed.

The solidifying material paste obtained for solidifying the metal pipe has a low viscosity of 5 poise and an excellent fluidity. Therefore, when the solidifying material paste is discharged from the kneading machine 10, if the pinch valve 22 is fully opened, the solidifying material paste may overflow from the drum can 23 because the solidifying material paste injection speed is too fast. However, in the present embodiment, since the opening degree of the pinch valve 22 is adjusted by the controller 52 as described above, such a problem does not occur.

As described above, according to this embodiment, there is an advantage that various kinds of radioactive waste can be solidified by the same equipment. Therefore, the installation area of the radioactive material solidification treatment facility is reduced. In addition, the present embodiment remarkably reduces the burden on the operator as compared with the case where the kneading solidification and the injection solidification are performed by separate devices.

Further, when the solidified body produced by the above method was cut and the soundness was examined, it was found that the waste resin solidified body had no problem such as floating of the waste resin above the solidified body, and the miscellaneous solidified body. As for the solidified material, the solidified material uniformly penetrated into the center of the solidified material, and no harmful void was found. As a comparative example, under the above conditions when kneading and solidifying the waste resin,
When 1 kg of a water reducing agent (high-condensation product of naphthalenesulfonic acid formaldehyde) in the fluidizing agent supply tank 17 was added, the viscosity of the kneaded material was 10 poise or less, and the fluidity was increased.
A phenomenon was observed in which waste resin with a low specific gravity floated above the solidified body, which caused a problem with the soundness of the solidified body. Further, when the solid solid of the metal pipe was injected and solidified, only the addition of the water reducing agent was omitted under the above-mentioned conditions, and the viscosity of the kneaded material was 150 poise and the fluidity was remarkably lowered, and the central portion of the solidified body was reduced. However, the solidified material did not uniformly penetrate to the above and a large amount of voids were generated, which caused a problem. Thus, by adding no superplasticizer in kneading and solidification, and by adding superplasticizer in injection solidification, avoiding the complexity when adjusting the mixing amount of the solidifying material corresponding to the radioactive substance, We were able to treat many kinds of radioactive waste with a single solidification facility, and obtain a uniform and sound solidified product.

In this example, concentrated waste liquid, waste sludge, and incinerated ash were shown as wastes to be kneaded and solidified, but other heat insulating materials (glass wool), concrete,
A clad slurry or the like can be similarly solidified. Although metal pipes are shown as wastes to be injected and solidified, other concentrated waste liquids, pellets of waste resin, press lumps compressed and reduced by a high pressure press can be solidified in the same manner. Also,
Although C-type blast furnace cement is used as the solidifying material in this embodiment, any hydraulic solidifying material may be used, such as ordinary Portland cement, fiber reinforced cement, and cement glass.

The present embodiment is a second embodiment that does not include radioactive waste.
Since the kneaded material contains a fluidizing agent, and the first kneaded material containing the radioactive waste contains a smaller amount of the fluidizing agent than the fluidized agent contained in the second kneaded material, their fluidity is Adjustment can be easily performed. If the amount of solidifying material is small, the strength of the solidified body will not reach the prescribed strength, and conversely if the amount of solidifying material is larger than the required amount, the filling amount of radioactive waste into the solidifying container will decrease, the so-called volume reduction ratio is poor. Become. Therefore,
The adjustment range of the amount of solidifying material is small, and it is difficult to adjust the fluidity of each of the first and second kneaded products. However, in the present embodiment, it is not necessary to adjust the fluidity by adjusting the composition of the radioactive waste and the solidifying material, and the above fluidity can be easily adjusted.

(Embodiment 2) A radioactive solidification processing apparatus which is another embodiment of the present invention is shown in FIGS. 3 and 4. In the present embodiment, the case where the pellets obtained from the concentrated waste liquid or the waste resin are kneaded and solidified, and the press lumps of miscellaneous solids are solidified by injection solidification will be mainly described with respect to operation control.

The same components as those in the first embodiment are designated by the same reference numerals. A configuration different from that of the embodiment will be described. Piping 43,
46 and 49 are connected to the kneading machine 10A. A pellet tank 27 that stores an almond-shaped pellet 26 having a volume of about 15 cc, which is obtained by pulverizing the concentrated waste liquid or the waste resin by a thin film evaporation dryer (not shown), is connected to a screw feeder 29 by a pipe 53. It Valve 2
8 is provided in the pipe 53. Reference numeral 54 is a motor that drives a rotating screw in the screw feeder 29. The outlet of the screw feeder 29 is connected to the kneading machine 10A by a pipe 55. Weighing container 30 and valve 34
Is provided in the pipe 55. The solidifying material tank 15 is filled with fiber-reinforced cement containing 2% by weight of carbon transition as the main component of ordinary Portland cement. The fluidizing agent supply tank 17 is filled with an inorganic fluidizing agent (spherical silica fume).

As shown in FIG. 4, the kneading machine 10A is provided with a rotary shaft 57 in a casing 18A, and three kneading blades 2 are provided.
0 is attached to the rotating shaft 57 by the arm 58.
The motor 19 is arranged outside the casing 18A.
The belt 31 is attached to the shaft of the motor 19 and the rotating shaft 57. The sliding shutter 33 for discharging the kneaded material (the cross-sectional area of the opening is 300 cm ^{2 when} fully opened)
It is provided at the bottom of the casing 18A.

The controller 52A includes the weighing containers 12, 1
Weights measured by weight scales installed at 3, 14, and 30,
Liquid level measured by laser type liquid level gauge 35, and weighing scale 3
Enter the weight measured in 7. Controller 52A
Are valves 28, 34, 44, 45, 47, 48, 50
And 51, the motors 19 and 54 are driven, the shutter 33 is opened and closed, and the vibrator 36 is started and stopped. The memory (not shown) of the controller 52A has the pellets 300 in addition to the mixing ratio of the solidifying material, water and the fluidizing agent for each radioactive waste described in Table 1 of the first embodiment.
200 kg of fiber-reinforced cement and 100 kg of water per kg
And a mixing ratio of 0 kg of fluidizing agent, and a press lump of miscellaneous solid (a miscellaneous solid mainly composed of a metal pipe with a diameter of about 45 cm and a height of about 20 cm, which has been compressed and reduced by a high-pressure press at about 1,000 tons and a heat insulating material) Fiber reinforced cement 40 for 3 pieces
The compounding ratios of 0 kg, 200 kg of water, and 20 kg of a spherical silica fume which is a fluidizing agent are stored as set values.

First, the solidification treatment of pellets will be described. The operator sets the selection switch of the operation panel 25 to pellet and pushes the start button. The start signal generated by this operation is input to the controller 52A.
The controller 52A opens the valve 28 and activates the motor 54. Rotated screw feeder 2
9 transfers the pellets 26 in the pellet tank 27 into the weighing container 30. When the measured value of the weight scale (load cell) provided in the weighing container 30 reaches 300 kg, the controller 52A closes the valve 28 and stops the motor 54. Within the weighing container 30 is a 300 kg pellet 26.

In the meantime, the controller 52A selects the substance necessary for preparing the kneaded product including pellets, based on the information of the compounding ratio for obtaining the kneaded product stored in the memory. This kneaded product requires a solidifying material and water. Therefore, the controller 52A outputs the open signal of the valves 44 and 47 to the corresponding valve. Valve 44
And 47 are opened. Fiber-reinforced cement is supplied into the measuring container 12, and water is supplied into the measuring container 13. The controller 52A closes the valves 44 and 47 when the measured values of 200 kg of fiber-reinforced cement and 100 kg of water are input from the weighing scales of the weighing containers 12 and 13, and then the valve 4 is closed.
Control to open 5, 48 is performed. Fiber-reinforced cement 2 mentioned above
00kg and 100kg of water, casing 1 of kneader 10A
8A is supplied. Before supplying these, the controller 52A drives the motor 19. The fiber-reinforced cement and water are kneaded by the rotation of the kneading blade 20, and the solidifying material paste is prepared in the kneader 10A. The controller 52A opens the valve 34 when the kneading time of the solidified material paste has passed 2 minutes. 300 kg of empty-measured pellets in the weighing container 30 are supplied into the kneading machine 10. Thereafter, the kneading is continued for another 2 minutes under the control of the controller 52A. The controller 52A uses the kneading blade 20.
The shutter 33 is controlled to open by 100 cm ² while continuing to rotate. As a result, the kneaded material in the kneading machine 10A containing the pellets is injected into the drum can 23 arranged below the shutter 33 at a flow rate of about 40 kg / min. During the injection of the kneaded material, vibration by the vibrator 36 is applied to the drum can 23. This is to prevent the generation of voids inside the solidified body due to the high viscosity of the kneaded product. The start and stop of the vibration by the vibration exciter 36 are controlled by the controller 52A.

The amount of the kneaded material filled in the drum can 23 is measured by a laser type liquid level gauge 35. The controller 52A indicates that the liquid level of the kneaded material in the drum can 23 measured by the liquid level gauge 35 is such that the filling amount of the kneaded material is approximately 80
When it is determined that the level corresponding to the case of occupying% is reached, the shutter 33 is closed. After that, the production of the first solidified body is completed by sealing the drum can 23 with the lid. In addition, the weight of the kneaded material discharged and filled in the drum can 23 at this time is 450 kg, which is measured by the weight scale 37. This measured value is input to the controller 52A. The solidified product obtained as described above is transferred to a storage location. Kneading machine 1 with new empty drum 23
Set again below 0.

Drum can 2 when producing the first solidified body
The fact that 150 kg of the kneaded material remains in the kneading machine 10 when 3 is sealed is obtained by the calculation by the calculation means in the controller 52A based on the measurement value of the weighing scale 37 (the prepared kneaded material 600 kg In contrast, the amount discharged to the drum is 450 kg). The calculation means assumes that the drum can 23 is filled with 450 kg of the kneaded material measured by the weight scale 37 even in the next solidification process, and the kneading machine 1
Since 150 kg of kneaded material remains in 0, the amount of kneaded material to be newly created is equal to the difference of 300.
Calculated to be kg (distribution ratio is 150 kg of pellets, 100 kg of cement, 50 kg of water). The distribution ratio is obtained based on the distribution ratio stored in the memory.

The second solidified body is produced by using the kneaded material remaining in the kneading machine 10 after the production of the first solidified body and the kneaded material newly made in the kneading machine 10. First, the shutter 33 is controlled by the controller 52A.
Is opened in the same manner as described above, and the kneaded material remaining in the kneading machine 10 is filled in the drum can 23 arranged below the kneading machine 10. A new kneaded product is created under the control of the controller 52A, like the first kneaded product. that time,
The controller 52A uses the pellet 15 calculated by the calculation means.
The radioactive waste solidification processor is controlled so as to obtain a kneaded product of 0 kg, 100 kg of cement and 50 kg of water. The newly prepared kneaded material is placed below the kneading machine 10 and kneading machine 1
Drum can 23 filled with the kneaded material remaining in 0
Filled inside. At this time, the liquid level gauge 35 and the weight gauge 37
The measured value is transmitted to the controller 52A, and the calculation means calculates the residual amount of the kneaded material in the kneading machine 10 after discharging the kneaded material of 5 kg.
Was calculated by calculation.

As described above, the solidification treatment of the day was completed, and the kneading machine 10 was washed.
Since it is as small as kg, the amount of secondary waste generated could be kept to a small amount. On the other hand, in the second batch solidification treatment for producing the second solidified body, the same composition as the first batch (pellet 300 kg, cement 200 kg, water 10
0 kg), more than 300 kg of kneaded material remains after the solidification treatment. That is, by simultaneously monitoring the liquid level and the weight in the solidification container, it is possible to prevent troubles in which the kneaded product overflows from the drum can 23, and to significantly reduce the amount of secondary radioactive waste generated in the solidification process. it can.

Next, the case where the solidified press lump or the like is solidified by pouring and solidifying will be described. One drum can in the miscellaneous solid supply area 24 of three miscellaneous solid press lumps whose main components are metal pipes with a diameter of approximately 45 cm and a height of approximately 20 cm that have been compressed and reduced to approximately 1000 tons by a high-pressure press and a heat insulating material. It is stored in 23.

The operator sets the selection switch of the operation panel 25 to a coarse solid and pushes the start button. The start signal is input to the controller 52A. The controller 52A is
As in the case of the pellets described above, the radioactive substance solidification treatment device is controlled. As a result, a solidified product of miscellaneous solids can be obtained. The difference from the case of obtaining a solidified body of pellets will be mainly described.

The controller 52A, based on the compounding ratio information stored in the memory for obtaining the kneaded material, is a substance necessary for solidifying the miscellaneous solid, that is, a solidifying material,
Select water and superplasticizer. To direct these substances into each weighing container, controller 52A includes valves 44, 4
Control to open 7 and 50 is performed. As a result, fiber-reinforced cement is placed in the measuring container 12, water is placed in the measuring container 13,
A spherical spherical silica fume is supplied into the measuring container 14. The controller 52A includes the weighing containers 12, 13 and 1
400 kg of fiber reinforced cement, which is the set value of the compounding ratio stored in the memory, the measured weights of the fiber reinforced cement, water and spherical silica fume input from each weighing scale of 4;
When the water reaches 200 kg and the spherical silica fume reaches 20 kg, the valves 44, 47 and 50 are closed, and then the valves 45, 48 and 51 are opened. 400 kg of the above fiber reinforced cement, 200 kg of water and 20 kg of spherical silica fume are supplied into the casing 18A of the kneading machine 10A and kneaded by the rotation of the kneading blades 20. Therefore, the solidifying material paste is prepared in the kneading machine 10A.

A drum can 23 accommodating three pressed solid lumps is set below the kneading machine 10. The controller 52A determines that the cross-sectional area of the opening of the shutter 33 is 2 cm ² when the kneading time of the solidified material paste has passed 2 minutes.
The control for opening the shutter 33 is performed so that Since the solidifying material paste does not contain radioactive waste, it has extremely good fluidity (viscosity of 5 poise or less), and the shutter 33 is opened to only 2 cm ² , and the solidifying material paste is about 1
At a rate of 0 kg / min, the mixture is poured into a drum can 23 containing three pressed solid blocks. At this time, the solidified material paste is permeated not only into the gap between the drum can 23 and the pressed mass but also into the pressed mass, so that the injection speed of the solidified material paste is kept low and at the same time, the vibrator 36 is applied to the drum can 23.
Gives a stronger vibration. After about 8 minutes, the liquid level of the solidified material paste reached a level 5 cm below the upper end of the drum. When the controller 52A determines that the solidified material paste has reached a level 5 cm below the upper end of the drum based on the measurement signal of the liquid level gauge 35, the shutter 52 is closed and the solidified material paste is supplied into the drum can 23. To stop. The upper end of the drum 23 is sealed with a lid. This completes the first batch solidification process. The amount of the kneaded material (solidified material paste) injected into the drum can 23 is 17
As with the 0 kg pellet, the controller 52
The calculation means in A inputs 170 kg of the weight of the solidifying material paste in the drum can 23 measured by the weight scale 37,
The weight of the solidifying material paste remaining in the kneading machine 10A is determined. This weight is 450 kg.

Next, using the solidifying material paste remaining in the kneading machine 10A, 350 kg of metal pipe not pressed.
Was injected and solidified into a new drum 23 in which was previously filled. As a result, it was found from the signal of the weighing scale 37 that about 190 kg of the kneaded material remained in the kneading machine 10 even after the second batch was completed. Therefore, as the third batch,
When the solidification treatment of the press lumps was performed in the same manner as in the first batch, the final residual amount of the solidification material paste in the kneading machine 10 was 10 kg, so this was treated as secondary waste,
A series of solidification treatment was completed.

As described above, in this embodiment, by simultaneously monitoring the liquid level and the weight in the solidification container, the amount of the kneaded product to be discharged / filled into the solidification container can be appropriately controlled, and the kneaded product can be removed from the solidification container. It is possible to prevent troubles such as overflow, and at the same time, appropriately manage the operating conditions such as mixing of the solidifying material so as to minimize the amount of secondary waste generated. In particular, the latter management of operating conditions is an issue that inevitably occurs when attempting to solidify multiple types of waste with different specific gravities and shapes in a single facility. It is also possible to carry out by measuring the weight. Also in this example, as in Example 1, the fluidizing agent was added only in the case of injection solidification, but by this, solid wastes of both pellets and miscellaneous solids could be solidified. This embodiment can obtain the same effect as that of the first embodiment.

Further, in this embodiment, the pellets 26 were processed by kneading and solidification, but since the volume is a relatively large granular substance of about 15 cc, the concentrated waste liquid pellets 26 are preliminarily prepared in the drum can 23 like the miscellaneous solid waste. Fill it inside,
After that, it is also possible to perform so-called injection solidification in which the solidifying material paste is injected from the kneading machine 10. On the other hand, in this embodiment, the miscellaneous solid waste is injected and solidified, but it is also possible to shred and preliminarily knead and solidify the miscellaneous solid such as the heat insulating material and the rubber gloves. In other words, the proper use of kneading and solidification and injection solidification is not determined by the type of waste, but may be appropriately determined by the waste properties such as shape. Further, it goes without saying that a melted material of incinerated ash as shown in Japanese Patent Publication No. 4-50558 or a melted material of a heat insulating material, a rubber glove, a metal or the like can be similarly treated by injection solidification.

(Embodiment 3) As is clear from the embodiment described above, the processing procedure of the solidification processing according to the type of radioactive waste is stored in the memory of the controller 52A, and based on this processing procedure. When the control by the controller 52A is performed on the radioactive substance solidification processing device, not only the load on the operator can be reduced but also troubles such as valve switching mistakes caused by human error can be avoided.
In order to explain this in detail below, the radioactive substance solidification processing device shown in FIG. 3 is stored in the memory of the controller 52A as shown in FIG.
The processing procedure shown in is stored.

First, when the type of radioactive waste to be solidified is set by the selection switch, the designated type of radioactive waste is input to the controller 52A (step 60). Based on this entered information,
The amount of radioactive waste, solidifying material, water, fluidizing agent, etc., and the operation sequence of valves, kneading blades, etc. are determined based on the operation patterns stored in advance (step 6).
1). Next, according to this operation sequence, the kneading machine 10
A kneaded material is created in A (step 62). When the kneading is completed, the kneaded product is discharged into the drum can 23 (step 63). The discharge amount of the kneaded material into the drum can 23 is monitored by a liquid level monitoring device and a weight monitoring device to prevent the kneaded material from overflowing the drum can 23 and at the same time.
After the discharge is completed, the amount of the kneaded material remaining in the kneader 10A is calculated. If the amount of kneaded material is equal to or greater than the specified value (usually another batch solidified body can be produced), a new drum can 23 is set below the kneading machine 10A (step 65), and the discharge of the kneaded material is continued. In addition, when it is below the specified value, it is possible to continue the solidification treatment, but it is also possible to finish the solidification treatment by carrying out a post-treatment such as washing. When the solidification treatment is continued, a new blending amount (waste, solidifying material, solidifying material, etc.) is usually taken into consideration in consideration of the amount of the kneaded material remaining in the kneading machine 10A.
Determine the weight of water, superplasticizer, etc.). As a result, as described in Example 2, it is possible to minimize the amount of secondary waste generated.

Further, in FIG. 6, only the target waste of the solidification treatment is designated first, but it is also possible to designate the treatment amount of the target waste at the same time. In this case, the amount of waste, solidifying material, etc. per batch is calculated in advance according to the designated amount of waste to be treated, and the number of batches until the end of treatment is also calculated. Then, when the first batch is completed, the compounding amount of the second batch is slightly modified, if necessary, from the amount of the residue in the kneader and the like. Specifically, when the amount of residue is large, it is appropriate to reduce the compounding amount in the second batch. Further, if it is detected from the data of the liquid level monitoring device that the amount of the kneaded material prepared in the first batch is small and the solidification container is not filled with a sufficient amount of the kneaded material, the compounding amount of the next batch is increased. You can do it like this. The same applies to subsequent batches.

This embodiment can obtain the same effect as the second embodiment.

(Embodiment 4) In Embodiments 1 and 2, a single solidifying material is used to solidify many kinds of radioactive waste. However, for example, when solidifying a miscellaneous solid, a cement having low alkalinity as shown in Japanese Patent Application No. 4-249937 is particularly desirable, and when solidifying waste sludge, Japanese Patent Application No. 2-322866. Cement added with nuclide-adsorptive fiber as disclosed in the publication is particularly desirable, and for pellets, alkali silicate hydraulic solidifying material as disclosed in Japanese Patent Application No. 56-80972 is particularly desirable. Therefore, if a plurality of solidifying material tanks are provided and the most desirable solidifying material is selected according to the radioactive waste to be solidified and supplied to the kneader, the physical properties of the solidified product obtained can be further improved. Is possible.

In the case where a plurality of solidifying material tanks are provided in this manner, when the target waste is first designated on the operation panel 25, which solidifying material tank of the solidifying material is to be supplied to the kneader is calculated beforehand. Then, the algorithm of the controller may be improved so as to determine the operation sequence of the valve or the like in accordance with the above.

[0069]

According to the present invention of claim 1, the first kneaded product and the second kneaded product can be obtained in the same kneader, and the radioactive solidification treatment facility can be made compact. Therefore, the installation area occupied by the radioactive solidification treatment facility can be reduced.

According to the third and fourth aspects of the present invention, good penetration can be achieved between the radioactive wastes filled in the solidification container,
The solidified body obtained when the radioactive waste is pre-filled in the solidification container becomes a uniform product with very few voids. Further, the radioactive waste can be prevented from being unevenly distributed in a part of the region, particularly the upper part or the lower part in the solidified body of the first kneaded material containing the radioactive waste, and a uniform solidified body can be obtained.

According to the invention of claim 5, it is not necessary to adjust the fluidity by adjusting the composition of the radioactive waste and the solidifying material, and the fluidity of the first and second kneaded products can be easily adjusted. it can.

According to the invention of claim 7, the amount of the kneaded material to be newly prepared can be determined in consideration of the residual amount of the kneaded material in the kneading machine. Therefore, the amount of secondary radioactive waste generated by the solidification treatment can be significantly reduced.

[Brief description of drawings]

FIG. 1 is a configuration diagram of a radioactive substance solidification processing apparatus according to a preferred embodiment of the present invention.

FIG. 2 is a vertical sectional view of the kneading machine shown in FIG.

FIG. 3 is a configuration diagram of a radioactive substance solidification processing apparatus according to another embodiment of the present invention.

FIG. 4 is a structural diagram of the kneading machine shown in FIG.

5 is a cross-sectional view of a casing portion of the kneader of FIG.

FIG. 6 is an explanatory diagram of a processing procedure executed by a controller of the radioactive substance solidification processing apparatus according to another embodiment of the present invention.

[Explanation of symbols]

1 ... Concentrated waste liquid, 3 ... Waste resin, 5 ... Incinerated ash, 10, 10A
... Kneader, 15 ... Solidifying material tank, 16 ... Water tank, 17
... fluidizing agent supply tank, 20 ... kneading blades, 21 ... knife gate valve, 22 ... pinch valve, 23 ... drum can, 24
... Miscellaneous solid supply area, 25 ... Control panel, 26 ... Pellet,
30 ... Measuring instrument, 33 ... Shutter, 35 ... Liquid level gauge, 37
... Weighing scale, 52, 52A ... Controller.

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

Claims (7)

[Claims] 1. A first kneaded product obtained by kneading at least three substances of a hydraulic solidifying material, water and radioactive waste in a kneading machine is poured into a solidification container to remove at least the hydraulic waste. A method for solidifying radioactive waste, which comprises injecting a second kneaded product obtained by kneading two substances, a solidifying material and water, in the kneader into a solidifying container previously filled with radioactive waste. . 2. The radioactive waste contained in the first kneaded product is at least a concentrated waste liquid, a waste ion exchange resin, an incinerated ash,
The radioactive waste that contains one of the powder and pellets of the concentrated waste liquid and shredded miscellaneous solids and is filled in the solidification container into which the second kneaded material is injected is at least noncombustible miscellaneous solids. The method for solidifying radioactive waste according to claim 1, further comprising one of: and a pellet. 3. The method for solidifying the radioactive waste according to claim 1, wherein the fluidity of the second kneaded product obtained by the kneader is higher than that of the first kneaded product obtained by the kneader. . 4. The second kneaded material obtained by the kneading machine contains a fluidizing agent, and the first kneaded material obtained by the kneading machine is the fluidized material contained in the second kneaded material. The method for solidifying radioactive waste according to claim 1, which contains a fluidizing agent in an amount smaller than that of the agent. 5. The second kneaded material obtained by the kneading machine contains a fluidizing agent, and the first kneading material obtained by the kneading machine does not contain a fluidizing agent. Solidification method for radioactive waste. 6. The method for solidifying radioactive waste according to claim 4, wherein the fluidizing agent is an inorganic fluidizing agent or a surfactant-based fluidizing agent. 7. When filling the solidification container with the first or second kneaded product in the kneading machine, the liquid level of the kneaded product injected into the solidification container is detected, and the liquid level becomes a predetermined value. The radioactive waste according to claim 1, 2, 3, 4, or 5, wherein the weight of the solidification container is detected when the temperature reaches a certain level, and the amount of the kneaded material remaining in the kneader is determined based on the detected weight. Solidification treatment method.