JPH085794A - Solidification equipment and method for radioactive waste pellet - Google Patents

Abstract

PURPOSE:To enable solidifying in uniformly dispersed state by using the same equipment in the solidification equipment and method for radioactive waste material pellet even for waste pellets of different kinds. CONSTITUTION:When one kind of pellet is selected from among pellets A, B, C by operating a selection key 16b, driving of transportation devices 7a to 7c corresponding to a controller 17 is started and the pellets selected from the corresponding storage vessels 1a to 1c are measured by a meter 11, and sent to a mixing tank 6. With a controller 18, bulk volume corresponding to the pellet weight transported to the mixing tank 6 is obtained from a correlation corresponding to the selected pellets, a target weight of the solid material S corresponding to the difference between the target bulk volume and the pellet bulk volume is obtained from the correlation of the solid material and the solid material S for the weight is measured with a meter 12 and sent to the mixing tank 6. These are mixed with solidifier and water and thrown in a solidifying vessel 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus and method for solidifying various radioactive wastes generated from a nuclear power plant, etc., and in particular, pellets obtained by compression-molding dried powders of the radioactive waste are solidified. And a method for solidifying radioactive waste pellets that solidify in a solidifying container.

[0002]

2. Description of the Related Art Numerous wastes containing radionuclides are generated from nuclear power plants, etc., and these are safely stored in the facility in a drum or the like, or solidified solidified. It is also stored in the facility as a body. The solidified solidified product is mainly solidified by kneading liquid waste with a solidifying material such as cement, and solid waste, for example, liquid waste is dried and powdered and pressed into pellets. Most of the pellets, used ion-exchange resins and miscellaneous solids are not solidified and are stored and stored in the facility.

Regarding low-level waste generated from a nuclear power plant, a method of embedding and managing it in a shallow layer has been embodied in recent years, and in some cases, mainly solidification of liquid waste is carried out. ing. For burying in shallow ground, pellets obtained by dry powdering liquid waste and pressing it into pellets and solidified products of used ion-exchange resin are also subject to burying. It becomes possible to embed like a solidified body obtained by solidifying.

A conventional technique for solidifying pelletized waste (waste pellets) is disclosed in Japanese Patent Laid-Open No. 57-93299.
There is one described in the publication. This is to fill pellets of waste into a container and inject water glass as a liquid solidifying material from the upper opening of the filling container.

Further, as a conventional technique for preventing uneven distribution of pellets in a solidified body when solidifying waste pellets, there is a method described in JP-A-60-238800. This is to use a solidifying material having a higher specific gravity than the waste pellets, as the first step, inject a predetermined amount of the solidifying material into the solidification container, then throw in the waste pellets, and as the second step, place the solidifying material on top. Is solidified by injecting it into the solid waste, and is a solidification method for maintaining the waste pellets near the center of the solidified body.

As another method for preventing uneven distribution of waste pellets in a solidified body, the specific gravity of the solidified material is adjusted as described in JP-A-63-167297 and JP-A-3-189600. There is a way to do it. These methods are
For example, lightweight aggregate or sand is added to a solidifying material such as cement to adjust the paste specific gravity of the solidifying material to prevent the pellets from floating.

On the other hand, a plastic solidification method using a thermosetting resin as a solidifying material is known. As a method for preventing the sedimentation of radioactive waste in the solidifying method until the thermosetting resin gels, JP-B-60-17080. There is one described in the publication. This is the amount of radioactive filler that corresponds to the difference between the planned input amount of radioactive waste and the actual input amount when solidification of dried liquid or slurry waste using thermosetting resin. For example, silica sand is filled to prevent sedimentation of waste.

[0008]

As described above, as for low-level waste generated from a nuclear power plant, a method of embedding and managing it in a shallow layer has been embodied. Some of the waste is mainly liquid waste. The embedding of the solidified solidified material is carried out.
At the time of burial, evaluation was carried out with a sufficient safety factor in mind, and it was evaluated as safe, but at that time, some solid wastes, facilities, etc. Conditions such as performance or material are required. For example, regarding the solidified waste, it is required that the waste containing the radionuclide be uniformly solidified without being unevenly distributed only in a part.

When the waste is in a liquid state, a solidified body is usually prepared by mixing the liquid waste with a solidifying material such as cement, so that the waste is uniformly dispersed in the solidified body. I won't.

However, when the waste is solid such as pellets, the dispersion of the waste in the solidified body depends on the type of solidifying material used, the type of solid waste, and the amount of waste filling. Expected to vary in degree. For example, when the waste is pellets, the pellets have different main components depending on the type of waste before being pelletized, and the specific gravity of the pellets varies accordingly. If the specific gravity of the pellet is larger than that of the solidifying material, the pellet will settle at the bottom of the solidified body. Conversely, if the specific gravity is small, it will float above the solidified body. When the packing amount of the pellets is large, the pellets interfere with each other, and such sedimentation and floating do not pose a problem. However, there are cases where it is necessary to reduce the filling amount due to restrictions on the surface dose rate of the solidified body, and in this case, sedimentation or floating of the pellet becomes remarkable, and a part of the solidified body,
For example, the pellets are unevenly distributed only at the bottom and top of the solidified body.

In the prior art described in Japanese Patent Laid-Open No. 57-93299, the solidifying material paste to be injected is non-radioactive, and the kneading machine for preparing the solidifying material paste is also non-radioactive. Also, there is an advantage that maintenance becomes easy. However, when the specific gravity of the pellet-shaped waste material and that of the solidifying material are significantly different, the problem that the pellets are unevenly distributed as described above occurs when the filling amount of the waste material is small.

In the prior art disclosed in Japanese Patent Application Laid-Open No. 60-238800, the solidified material is injected in two steps to hold the waste pellets near the center of the solidified body, so that the waste pellets are placed above the solidified body. Or uneven distribution at the bottom can be avoided. However, since the waste pellets are not dispersed, the pellets are unevenly distributed even though it is at the center.

In the prior arts disclosed in Japanese Patent Laid-Open Nos. 63-167297 and 3-189600, light aggregates are added to adjust the paste specific gravity of the solidifying material to prevent the pellets from floating. There is. With this method, it is relatively easy to increase the paste specific gravity of the solidifying material,
There is a problem that it is difficult to reduce the specific gravity. Also,
When the difference between the specific gravity of the paste of the solidifying material and the specific gravity of the pellet becomes large, there is a problem that it is difficult to adjust the specific gravity. Further, when one type of pellets is selected and solidified from several types of waste pellets having different specific gravities, it is necessary to change the specific gravity of the solidifying material according to the type of waste pellets. Therefore, there is a problem that the solidification treatment equipment becomes complicated and the operation becomes complicated and difficult.

In the prior art disclosed in Japanese Examined Patent Publication No. 60-17080, a thermosetting resin is prepared by adding a radioactive filler in an amount corresponding to the difference between the planned amount of radioactive waste and the actual amount of radioactive waste. Prevent the sedimentation of waste in. However, when attempting to solidify the waste pellets by this technique, silica sand having a particle size much smaller than that of the pellets is used as the filler, and thus the silica sand cannot prevent uneven distribution of the pellets. Also, since the specific gravity of the pellets differs when the types of pellets are different, even if the same weight of pellets is put into the solidification container, the volume of the pellets in the solidification container is different if the types of pellets are different, and the pellets are uniform in the solidified body The weight of the filler needed to disperse in is also different. For this reason, pellets of different types cannot be solidified in the same equipment in a uniformly dispersed state.

It is an object of the present invention to provide a solid waste treatment facility and method for treating radioactive waste pellets which can solidify even different types of waste pellets in a uniformly dispersed state using the same facility. It is in.

[0016]

In order to achieve the above object, the waste pellet solidification treatment equipment of the present invention adopts the following constitution. That is, radioactive waste is dried and powdered, and compression-molded pellets are solidified using a solidifying material in a solidification container. A container, a solid substance storage container in which a solid substance having the same size as the pellets is stored, and pellets and solid substances are transferred from the pellet storage container and the solid substance storage container, and they are mixed. A first kneading tank for stirring and charging into the solidification container, a pellet transfer means for measuring and transferring each pellet from the plurality of pellet storage containers to the first kneading tank, and the solid substance storage container A solid substance transfer means for measuring the solid substance from the sample and transferring it to the first kneading tank, and selecting one kind of pellet from the different kinds of pellets First transfer control means for controlling the pellet transfer means so that the selected pellets of a predetermined weight are transferred to the first kneading tank, and the pellets selected by the first transfer control means are solidified. A target weight of the solid substance required to uniformly disperse and solidify in the container is determined, and the solid substance transfer means is provided so that the target amount of the solid substance is transferred to the first kneading tank. And a second transfer control unit for controlling.

In the above solidification treatment equipment, preferably,
The second transfer control means stores, for each of the different types of pellets, the correlation between the weight of the pellet and the weight of the solid substance necessary for uniformly dispersing and solidifying the pellet in the solidification container, and the correlation is stored. Based on the above, the solid substance weight corresponding to the pellet of a predetermined weight transferred to the first kneading tank is determined as the target weight of the solid substance.

Further, preferably, the second transfer control means has a first correlation between a pellet weight and a bulk volume in the solidification container for each of the different types of pellets, and a solid substance weight in the solidification container. The second correlation with the bulk volume is stored, the first correlation corresponding to the selected pellet is selected, and the first correlation and the second correlation are selected.
The target weight of the solid substance is determined from the correlation, the predetermined weight of the pellets transferred to the first kneading tank, and the target bulk volume required to uniformly disperse and solidify the pellets in the solidification container.

The solidification treatment facility is preferably
The second transfer control means further comprises a first operation means for inputting a numerical value of target uniformity of pellet dispersion in the solidification container, and the second transfer control means targets the solid substance so as to obtain the target uniformity. Calculate the weight. In this case, preferably, the second transfer control means stores the correlation between the pellet dispersion uniformity and the bulk volume in the solidification container, and the correlation is input by the first operating means based on this correlation. The bulk volume corresponding to the target uniformity is determined, and this bulk volume is set as the target bulk volume.

Further preferably, the solidification treatment facility is:
Second operation means for instructing the selection of any one of the different types of pellets is further provided, and the first transfer control means transfers the pellets to the first kneading tank in response to a selection signal from the second operation means. Select the type of pellet to be used.

The solidification treatment facility comprises a solidification material storage container and a water storage container for containing a solidification material and added water, respectively.
Solidifying material and water transferring means for measuring and transferring the solidifying material and water from the solidifying material storage container and the water storage container, respectively, to the first kneading tank, and the predetermined pellets to be transferred to the first kneading tank. And a third transfer control means for controlling the solidifying material and water transferring means so that the solidifying material and the water having a weight and a weight suitable for the target weight of the solid substance are transferred to the first kneading tank. You may have it. In this case, the target bulk volume is 30% or more of the volume of the solidification container.

Further, the solidification treatment facility comprises a solidification material storage container and a water storage container for respectively containing the solidification material and the added water, and the solidification material and the added water are transferred from the solidification material storage container and the water storage container, A second kneading tank for stirring and mixing these and transferring to the solidifying container, and a solidifying material for measuring and solidifying the solidifying material and water from the solidifying material storage container and the water storage container, respectively, and transferring to the second kneading tank. A water transfer means, and a solidifying material and water having a weight suitable for the predetermined weight of the pellets transferred to the first kneading tank and the target weight of the solid substance are transferred to the second kneading tank. A third transfer control unit that controls the solidifying material and the water transfer unit may be further included. In this case, the target bulk volume is 70% or more of the volume of the solidification container.

In the solidification treatment facility, preferably, the first transfer control means is a dose rate detecting means for measuring a surface dose rate of pellets transferred to the first kneading tank, and the dose rate detecting means. And a means for stopping the transfer of the pellets to the first kneading tank when the surface dose rate obtained by the means reaches a reference value. In this case, preferably, the second transfer control means inputs the processing data from the first transfer control means, and when the surface dose rate reaches a reference value, the second pellet transfer means is weighed. The target weight of the solid substance is calculated from the weight of the pellet.

Further, in the above solidification treatment facility, preferably, the pellet transfer means and the solid substance transfer means respectively receive the pellet and the solid substance transferred to the first kneading tank, respectively, and intermediately receive the weight thereof. It has a measuring instrument for measuring.

Further, the waste pellet solidifying method of the present invention adopts the following constitution in order to achieve the above object. In other words, in a radioactive waste pellet solidification treatment method in which radioactive waste is dried and powdered, and compression-molded pellets are solidified in a solidification container using a solidifying material, a solid substance having the same size as the pellets. Is prepared in advance, one type of pellets is selected from different types of pellets, a predetermined weight of the selected pellets is transferred to a kneading tank, and the selected pellets are uniformly dispersed and solidified in the solidification container. Determining the target weight of the solid substance required to do, transferring the solid substance of the target weight to the kneading tank, mixing and stirring the pellets and the solid substance in the kneading tank, Each procedure of putting in a solidification container is adopted.

In the above solidification treatment method, preferably
The procedure for obtaining the target weight of the solid substance is the first of the pellet weight and the solid substance weight necessary to uniformly disperse and solidify the pellets in the solidification container, which is preset for each of the different types of pellets. Selecting a first correlation corresponding to the pellets selected from the correlations, determining a bulk volume corresponding to the weight of the pellets transferred to the kneading tank based on the selected first correlations, uniformly distributing the pellets in the solidification container The difference between the target bulk volume necessary for dispersion and solidification and the calculated bulk volume is calculated, and the solid state corresponding to the difference in the bulk volume is calculated based on the second correlation between the weight of the solid substance and the bulk volume. Determine the weight of the substance as the target weight.

Further, in the above solidification treatment method, the solidification material and the added water may be transferred to the kneading tank together with the pellets and the solid substance, and they may be mixed and stirred and poured into the solidification container. In this case, the target bulk volume is 30% or more of the volume of the solidification container.

It is also possible that after the pellet and the solid substance are mixed and stirred, the mixture is poured into the solidification container, and then the solidification material and the added water are kneaded into the solidification container.
In this case, the target bulk volume is 70 times the volume of the solidification container.
% Or more.

Preferably, the weight and surface dose rate of the pellets transferred to the kneading tank are measured, and the bulk volume of the pellets is calculated based on the first correlation from the pellet weight when the surface dose rate reaches a reference value. Ask for.

[0030]

The reason why the waste pellets are unevenly distributed in the solidified body is that the specific gravity of the pellets is different from that of the solidifying material. If the specific gravity of the pellets is larger than that of the solidifying material paste, the pellets settle, and conversely, they rise. The present inventors have found that by adding an appropriate amount of a solid substance having the same size as the pellet to the pellet, it is possible to suppress the sedimentation or floating of the pellet. This is because if the specific gravity of the pellet is different from that of the solidifying material, the pellet will try to settle or float in the solidifying material paste, but if a solid substance of the same size as the pellet is mixed, the solid substance Becomes an obstacle and cannot move,
This is because sedimentation or floating is suppressed.

Further, it has been found that when the solid substance is added to suppress the sedimentation or floating of the pellet as described above, the amount of the solid substance to be charged must be changed according to the type of the pellet. That is, since different types of pellets have different specific gravities, even if the same weight of pellets is put into the solidification container, the volume of the region occupied by the pellets in the solidification container, that is, the “bulk volume”, is not the same. Therefore, it is necessary to change the input amount of the solid substance required to suppress the sedimentation or floating of the pellets.

The present invention is based on the above findings,
In the solidification treatment equipment of the present invention, the target weight of the solid substance required to uniformly disperse and solidify the pellets selected by the first transfer control means in the solidification container by the second transfer control means, and By controlling the solid substance transfer means so that the target amount of the solid substance is transferred to the first kneading tank, even if the waste pellets are of different types, the sedimentation or floating of the pellets can be appropriately suppressed. , Can be solidified in the state of being uniformly dispersed using the same equipment.

Further, it has been found that the target weight of the solid substance necessary for uniformly dispersing and solidifying the selected pellets in the solidifying container can be obtained as follows.

(A) Quantitatively grasp the uniformity of pellet dispersion in the solidification container by the "bulk volume" of the pellets in the solidification container; (b) Pellet weight and solidification container content for each type of pellet. In advance, the correlation with the "bulk volume" in (c) is determined in advance between the weight of the solid substance and the "bulk volume" in the solidification container; (d) In the above (c) Select the correlation corresponding to the selected pellet from the correlations, and calculate the "bulk volume" corresponding to the weight of the pellets transferred to the kneading tank based on the correlation; (e) The target uniformity grasped in (a) above The "bulk volume" corresponding to the sex is set as a target bulk volume, and the difference between the target bulk volume and the bulk volume obtained in (d) is calculated; (f) In (e) based on the correlation in (c) above. Solid state corresponding to the obtained bulk volume difference Determining the weight of the quality as the target weight of the solid material.

The above correlations (b) and (c) may be combined into one correlation between the weight of the pellet and the weight of the solid substance with the bulk volume as a parameter. Here, the “bulk volume” is the volume of the region occupied by the pellets (or solid substance or mixture thereof) charged in the solidification container as described above in the solidification container, and the pellets and the pellets (or the solid form). It is the volume including the gap between the substance and the solid substance or the pellet and the solid substance).

The present invention is based on the above findings, and in the solidification treatment equipment of the present invention, the pellet weight and the pellets are uniformly dispersed in the solidification container for each of the different types of pellets in the second transfer control means. By storing the correlation with the weight of the solid substance necessary for solidification, and obtaining the weight of the solid substance corresponding to the pellet of a predetermined weight transferred to the first kneading tank based on the correlation, the solid state can be obtained. The target weight of the substance is determined.

In the second transfer control means, a first correlation between the pellet weight and the bulk volume in the solidification container and a second correlation between the solid substance weight and the bulk volume in the solidification container for each of different types of pellets are provided. Is stored and the first correlation corresponding to the selected pellet is selected, and the first correlation, the second correlation, the predetermined weight of the pellet transferred to the first kneading tank, and the pellet in the solidification container. From the target bulk volume necessary to uniformly disperse and solidify
By performing the calculation of (f), the target weight of the solid substance can be obtained.

A first operation means for inputting a target homogeneity value of the pellet dispersion in the solidification container is further provided, and a target of the solid substance is obtained by the second transfer control means so as to obtain the target homogeneity. By calculating the weight, the uniformity can be freely set by the operator's operation.

The second transfer control means stores the correlation between the pellet dispersion uniformity and the bulk volume in the solidification container,
Based on this correlation, the bulk volume corresponding to the target uniformity input by the first operating means is obtained and set as the target bulk volume, whereby the target uniformity is quantitatively determined.

Second operation means for instructing the selection of any one of the different types of pellets is further provided, and the first transfer control means transfers the pellets to the first kneading tank in response to the selection signal from the second operation means. By selecting the type of pellets to be used, the operator can freely select the type of pellets and solidify the selected pellets in a uniformly dispersed state.

In (a) above, when quantitatively ascertaining the uniformity of pellet dispersion in the solidification container by the "bulk volume" of the pellets in the solidification container, the uniformity of pellet dispersion and the "bulk volume" of the pellets are used. The relationship depends on the kneading solidification method or the injection solidification method. The kneading and solidification method is a method in which pellets and a solidifying material are stirred and mixed together in a kneading tank and charged into a solidification container, and in this case, the uniformity of pellet dispersion and the "bulk volume" have a linear proportional relationship. No (see Figure 4). It is generally said that a homogeneity of 70% or more is required in consideration of a sufficient safety factor. In the case of the kneading and solidification method, "bulk volume" corresponds to 70% of homogeneity, and is 30% of the volume of the solidification container. Hit the degree. This is about 60 liters when the volume of the solidification container is 200 liters. On the other hand, the injection solidification method is a method of injecting the solidifying material paste into the solidification container after charging the pellets into the solidification container, and the uniformity of the pellet dispersion and the "bulk volume" are in a linear proportional relationship (Fig. 10). In this case, the "bulk volume" corresponding to 70% uniformity corresponds to 70% of the volume of the solidification container, and when the volume of the solidification container is 200 liters, it is about 1
40 liters.

In the solidification treatment facility of the present invention, solidification material and water transfer means for measuring and transferring the solidification material and water from the solidification material storage container and the water storage container, respectively, to the first kneading tank,
By further providing a third transfer control means for controlling the solidifying material and the water transfer means, a kneading and solidifying system facility can be obtained. In this case, the target bulk volume is 30 times the volume of the solidification container.
By setting the content to be not less than%, the uniformity of not less than 70% can be achieved.

A second kneading tank in which the solidifying material and the added water are transferred from the solidifying material storage container and the water storage container and are mixed by stirring and transferred to the solidifying container, and the solidifying material from the solidifying material storage container and the water storage container. And a water transfer means for measuring and transferring water and water to the second kneading tank, respectively, and a third transfer control means for controlling the solidification material and water transfer means. Equipment can be obtained. In this case, by setting the target bulk volume to 70% or more of the volume of the solidification container, uniformity of 70% or more is achieved.

Further, the first transfer control means is provided with a dose rate detecting means for measuring the surface dose rate of the pellets transferred to the first kneading tank, and the surface dose rate obtained by the dose rate detecting means is a reference value. By stopping the transfer of the pellets to the first kneading tank when the temperature reaches, the surface dose rate of the solidified body can be kept below the reference value. In this case, the processing data from the first transfer control means is input to the second transfer control means, and when the surface dose rate reaches the reference value, the pellet weight measured by the pellet transfer means is used to determine the target of the solid substance. By obtaining the weight, the target weight of the solid substance required to keep the surface dose rate of the solidified body below the reference value can be obtained.

By providing the pellet transfer means and the solid substance transfer means with a weighing device for receiving the pellet and the solid substance transferred to the first kneading tank, respectively, and measuring the weight thereof, the pellet and the solid substance are transferred. The substance-like substance can be transferred to the first kneading tank while being weighed.

Further, the solidification treatment method of the present invention has the above-mentioned (d).
The procedure (a) to (f) is carried out so that even waste pellets of different types can be appropriately suppressed from settling or floating up and can be solidified in a uniformly dispersed state using the same equipment. it can.

[0047]

Next, embodiments of the present invention will be described with reference to the drawings. First, a first embodiment of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to a kneading and solidification type solidification treatment facility.

In FIG. 1, the solidification treatment equipment of this embodiment has a plurality of pellet storage containers 1a, 1b, 1c for accommodating different types of pellets A, B, C, and a size comparable to the pellets. A solid substance storage container 2 in which the solid substance S is stored, a solidification material storage container 3 and a water storage container 4 in which a solidification material X and added water Y are respectively stored, and pellets sent from these respective containers, A kneading tank 6 in which a solidifying material, added water, and a solid substance are mixed and stirred, and the mixture is put into a solidifying container 5.
And pellet transfer devices 7a, 7b and 7c for transferring the respective pellets A, B and C from the pellet storage containers 1a, 1b and 1c to the kneading tank 6, and the solid substance S from the solid substance storage container 2 to the kneading tank Solid substance transfer device 8 for transferring to 6
And valves 9 and 10 for opening and closing pipes for transferring the solidified material X and the added water Y from the solidified material storage container 3 and the water storage container 4 to the kneading tank 6. The kneading tank 6 is a drive device 6
A valve 20 for opening and closing the pipe is provided in the discharge pipe, which includes a rotary stirring blade 6b connected to a.

Further, the solidification treatment equipment of the present embodiment is arranged such that the pellet weighing device 11 for receiving the pellets transferred to the kneading tank 6 and measuring the weight thereof and the solid substance transferred to the kneading tank 6 are intermediate. Solid material meter 12 for receiving the weight of the solid material, and the solid material meter 13 for measuring the weight of the solid material and the added water transferred to the kneading tank 6 respectively and the water meter 14 A radiation detector 15 for measuring the surface dose rate of the pellets housed in the pellet scale 11, an input key 16a for inputting a numerical value for the target uniformity of pellet dispersion in the solidification container 5, and different types of pellets A , B, C select key 1 to select any one
6b, an operation device 16 having a display 16c for displaying the contents of the input signal of the input key 16a and the selection signal of the selection key 16b, the weighing instruments 11-14, and the radiation detector 15.
And control devices 17, 18 and 19 for inputting signals from the operation keys 16a and 16b and controlling the operation of the transfer devices 7a to 7c and 8 and the valves 9 and 10.

Of the control devices 17, 18, 19, the control device 17 detects the detection signal from the radiation detector 15 and the operating device 1.
The selection signal of the selection key 16b from 6 is input to control the driving of the transfer devices 7a to 7c. The control device 18 receives the input signal of the input key 16a from the operation device 16 and the weighing instruments 11, 1
The detection signal from 2 and the processing signal from the control device 17 are input to control the driving of the transfer device 8. The control device 19 inputs the detection signals from the measuring instruments 13 and 14 and the processing signal from the control device 18, and controls the opening and closing of the valves 9 and 10.

In the above, the pellet transfer devices 7a-7
c and the pellet scale 11 are a plurality of pellet storage containers 1
The solid substance transfer device 8 and the solid substance measuring device 12 constitute the pellet substance transfer means for measuring the respective pellets A, B and C from a to 1c and transferring them to the kneading tank 6. A solid substance transfer means for measuring and transferring the solid substance S to the kneading tank 6 is constituted.

Further, the radiation detector 15 and the controller 17
Selects one type of pellets from different types of pellets A, B, and C, and transfers the pellets having the selected predetermined weight to the kneading tank 6, specifically, the pelletizing devices 7a to 7a. 7c, which constitutes the first transfer control means, controls the control device 18 from different types of pellets A,
For each of B and C, the correlation between the weight of the pellet and the weight of the solid substance S necessary for uniformly dispersing and solidifying the pellet in the solidification container 5 is stored, and the kneading tank 6 is stored in the kneading tank 6 based on the correlation. The solid substance weight corresponding to the pellets of a predetermined weight to be transferred is determined as the target weight of the solid substance S, and the solid substance transfer means is provided so that the target weight of the solid substance is transferred to the kneading tank 6. Specifically, it constitutes a second transfer control means for controlling the distribution device 8.

The valve 9 and the solidifying material meter 13 constitute a solidifying material transferring means for measuring the solidifying material X from the solidifying material storage container 3 and transferring it to the kneading tank 6, and the valve 10 and the water meter 14
Constitutes water transfer means for measuring water from the water storage container 4 and transferring it to the kneading tank 6. The controller 19 transfers the solidifying material and water so that the solidifying material X and the water Y having a weight suitable for the predetermined weight of the pellets transferred to the kneading tank 6 and the target weight of the solid substance are transferred to the kneading tank 6. It constitutes a means, specifically, a third transfer control means for controlling the valves 9 and 10.

The pellets A, B, and C contained in the pellet storage containers 1a, 1b, and 1c are obtained by dry-powdering radioactive waste and compression-molding it. The types of pellets include concentrated waste liquid pellets and resin pellets. The concentrated waste liquid pellets are formed by compressing and molding the concentrated waste liquid containing a mixture of inorganic salts and iron oxide as a main component, which is dried and powdered. Inorganic salts differ depending on the type of power plant. Sodium sulphate is the main component in boiling water power plants and sodium borate in pressurized water power plants. The resin pellets are obtained by dry-ionizing the ion exchange resin (granular or powdery) stored in the form of a slurry and compression-molding this. These have different specific gravities depending on the main components, and the specific gravity is heavy in the order of pellets containing sodium sulfate as the main component> pellets containing sodium borate as the main component> resin pellets. The pellet A is a concentrated waste liquid pellet containing sodium sulfate as a main component, the pellet B is a concentrated waste liquid pellet containing sodium borate as a main component, and the pellet C is a resin pellet, for example.

Any solid substance may be used as long as it has the same size as the pellet, and for example, gravel, crushed stone and the like can be used. Gravel is used in this embodiment.

As the solidifying material, a hydraulic solidifying material which is hardened by kneading with water, more specifically, a cement material is used. In this case, the pellet A containing sodium sulfate as a main component is heavier than the cement and thus sinks, and the other pellets B and C are lighter than the cement and floats.
The solidifying material is not limited to the cement-based material, and may be any organic material as long as it does not adversely affect the solidified body by acting on the pellet and the solid substance.

Details of the processing function of the controller 17 will be described with reference to the flowchart shown in FIG. First, the control device 17 uses the selection key 16b from the operating device 16 for pellets A,
The selection signals of B and C and the detection signal from the radiation detector 15 are input (step 100). Then, the operating device 16
One of the transfer devices 7a, 7b, and 7c corresponding to the selected pellet is driven based on the selection signal from (1) to transfer the selected pellet to the weighing device 11 (step 101). At the same time, based on the detection signal from the radiation detector 15, it is determined whether or not the surface dose rate of the pellets transferred to the weighing device 11 has reached the reference value (step 102). If the surface dose rate does not reach the reference value, the drive of the transfer device is continued, and if it reaches the reference value, the drive of the transfer device is stopped (step 1).
02). After that, the pellets transferred to the measuring device 11 are automatically sent to the kneading tank 6.

Details of the processing function of the controller 18 will be described with reference to the flowchart shown in FIG. First, the control device 18 selects a pellet selection signal from the operation device 16 with the selection key 16b, a uniformity input signal from the operation device 16 with the input key 16a, a pellet weight signal from the weighing device 11, and a weighing device 12 from the weighing device 12. Solid substance weight signal and control device 1
The processed signal from 7 is input (step 200). Next, the uniformity input signal from the operation device 16 and the uniformity input based on the correlation between the pellet dispersion uniformity and the bulk volume in the solidification container 5 shown in FIG. The target bulk volume Vt corresponding to is set (step 201).

Here, FIG. 4 shows the correlation between the pellet dispersion uniformity and the bulk volume in the case of the kneading and solidification method.
The solidification container 5 used had a capacity of 200 liters. As described above, in the kneading and solidification method, the uniformity of pellet dispersion and the bulk volume are not in a linear proportional relationship. Also, usually
It is said that the uniformity needs to be 70% or more in consideration of a sufficient safety factor, and the bulk volume corresponding to the uniformity of 70% corresponds to about 30% of the volume of the solidification container. This is 60 liters of the 200 liter solidification vessel 5.

Next, the pellet selection signal from the operating device 16 and the weight and bulk volume of the pellets in the solidification container 5 for each of the different types of pellets A, B and C shown in FIG. Correlation corresponding to the selected pellet is selected based on the correlation and the pellet bulk volume Vp corresponding to the pellet weight when the surface dose rate reaches the reference value based on the correlation and the processing signal from the controller 17. Calculate (step 202). Next, a difference ΔV = Vt−Vs between the target bulk volume Vt and the pellet bulk volume Vp is calculated (step 203), and this bulk volume difference ΔV and the solid in the solidification container 5 shown in FIG. Based on the correlation between the weight of the particulate matter (gravel) and the bulk volume, the weight of the solid particulate matter corresponding to the bulk volume difference ΔV is obtained as the target weight Wst (step 204). Next, the solid substance transfer device 8 is driven to transfer the solid substance S to the weighing device 12 (step 205), and based on the weight signal from the weighing device 12, the weight of the solid substance transferred to the weighing device 11 is measured. Determines whether the weight has reached the target weight Wst (step 20).
6). If the weight of the solid substance does not reach the target weight Wst, the drive of the transfer device 8 is continued, and if the weight of the solid substance reaches the target weight Wst, the drive of the transfer device 8 is stopped (step 207). After that, the solid substance transferred to the measuring device 12 is automatically sent to the kneading tank 6.

Details of the processing function of the control device 19 will be described with reference to the flowchart shown in FIG. The control device 19 first inputs the processing signal from the control device 18, the solidification material weight signal from the measuring instrument 13, and the water weight signal from the measuring instrument 14 (step 300). Then, based on the processing signal from the controller 18, the target weights Wxt, Wyt of the solidifying material (cement) X and the water Y are determined based on the pellet weight and the target weight Wst of the solid substance when the surface dose rate reaches the reference value. Is calculated (step 301). This can be calculated as follows. First, the mixing ratio of the solidifying material and water is determined in advance. This mixing ratio is determined by what is used as the solidifying material. For example, in the case of ordinary cement, a water / cement weight ratio of 4/5 is mixed to form a cement paste. Also,
Since this solidifying material paste also fills the gap between the waste pellets and the solid substance in the solidifying container 5,
The volume of the solidifying material paste required is obtained by subtracting the total volume of the waste pellets and the solid substance from the volume of the solidifying container (200 liters). Here, the accumulation of pellets is obtained from the weight of the pellets and its specific gravity, and the accumulation of solid substances is obtained from the weight of the solid substances (target weight) and its specific gravity. When the required volume of the solidifying material paste is obtained in this manner, the relationship between the volume of the solidifying material paste and the weight of the solidifying material and water is evaluated in advance as data corresponding to the above weight ratio, and this is used as a control device. By storing it in 19, the target weights Wxt and Wyt of the solidifying material and water corresponding to the required volume of the solidifying material paste can be obtained.

In this way, the target weight W of the solidifying material and water is
When xt and Wyt are obtained, the valves 9 and 10 are opened, the solidifying material X and the water Y are transferred to the measuring instruments 13 and 14 (steps 302 and 305), and the weighing signals are measured based on the weight signals from the measuring instruments 13 and 14. It is determined whether the solidifying material and the water transferred to the vessels 13 and 14 have reached the target weights Wxt and Wyt, respectively (steps 303 and 306). If the solidifying material and water do not reach the target weights Wxt and Wyt, respectively, the valves 9 and 10 are left open, and when the target weights Wxt and Wyt are reached, the valves 9 and 10 are closed (steps 304 and 3).
07). After that, the solidifying material and the water transferred to the scales 13 and 14 are automatically sent to the kneading tank 6.

Next, an operation example of the pellet solidification processing equipment of this embodiment will be described. First, the operator operates the input keys 16a of the operation device 16 to input the target uniformity in advance. As described above, the target uniformity is 7
Input 0% or more, for example, 90%. As a result, the control device 17 detects that the correlation shown in FIG.
A target bulk volume of about 100 liters, corresponding to a% homogeneity, is set. Next, the operator operates the selection key 16b of the operation device 16 to select a pellet desired to be solidified, for example, the pellet A from the pellets A, B, and C. Along with this, the controller 17 starts driving the transfer device 7a, and the pellets A are transferred from the storage container 1a to the weighing device 11.

When the pellets A selected in the weighing device 11 are transferred to the weighing device 11, the pellets A are weighed by the weighing device 11 by the above-described processing function of the control device 17, transferred to the kneading tank 6, and controlled. The solid substance, that is, the gravel S is measured by the measuring device 12 by the processing function of the device 18 described above, transferred to the kneading tank 6, and the solidifying material (cement) X and the water Y are measured by the processing function of the control device 13. , 1
4 is weighed and transferred to the kneading tank 6. For example, when the weight of the pellet A when the dose rate reaches the reference value is 50 kg, when 50 kg of the pellet A is transferred to the measuring device 11, the transfer of the pellet A to the measuring device 11 is stopped and the measuring device 11 From the kneading tank 6, 50 kg of the pellet A is transferred. Further, assuming that the target bulk volume is 100 liters as described above, the control device 18 obtains 40 liters as the bulk volume of the pellet A from the correlation corresponding to the pellet A shown in FIG. From the correlation, a target weight of 100 kg of the solid substance S corresponding to 60 liters, which is a difference between the target bulk volume of 100 liters and the bulk volume of the pellet A of 40 liters, is obtained, and the weighing device 12 reduces the weight of the solid substance S of 100 kg. Transferred to the kneading tank 6. Further, the control device 19 obtains the target weights Wxt and Wyt of the solidifying material (cement) X and water Y based on the weight 50 kg of the pellet A and the weight 100 kg of the solid substance S, and the measuring instrument 1
The solidifying material and the water are weighed by 3, 14 and transferred to the kneading tank 6.

The pellet A, the solid substance S, the solidifying material X and the water Y thus transferred to the kneading tank 6 are mixed and stirred in the kneading tank 6 by the rotary stirring blade 6b connected to the driving device 6a, and the valve The container 20 is opened and is transferred to the solidification container 5. The solidified body injected and transferred to the solidification container 5 and solidified was a sound solidified body in which the pellet A and the solid substance S were uniformly dispersed in the solidified material X as shown in FIG.

As described above, according to this embodiment, different kinds of waste pellets can be solidified in a state of being uniformly dispersed by using the same equipment.

A second embodiment of the present invention will be described with reference to FIGS. In this embodiment, the present invention is applied to a solidification treatment facility of injection solidification type. In the figure, the same members as those shown in FIG. 1 are designated by the same reference numerals.

In FIG. 9, the solidification treatment equipment of this embodiment has another kneading tank 30 in addition to the kneading tank 6, and the kneading tank 6 contains pellets and solids from the pellet storage containers 1a, 1b, 1c. The solid substance from the solid substance storage container 2 is transferred, the solidifying material and the added water from the solidifying material storage container 3 and the water storage container 4 are transferred to the kneading tank 30, and they are separately mixed and stirred. Similar to the kneading tank 6, the kneading tank 30 includes a rotary stirring blade 30b connected to the driving device 30a, and a valve 31 for opening and closing the pipe is provided in the discharge pipe.

The processing functions of the control device 17, the control device 18 and the control device 19 are substantially the same as those of the first embodiment. However, the controller 18 stores the correlation shown in FIG. 10 instead of the correlation shown in FIG. 4 as the correlation between the pellet dispersion uniformity in the solidification container 5 and the bulk volume because the injection solidification method is used in this embodiment. Has been done.

Here, FIG. 10 shows the correlation between the pellet dispersion uniformity and the bulk volume in the case of the injection solidification method, and the solidification container 5 similarly has a capacity of 200 liters. As described above, in the injection solidification method, the uniformity of pellet dispersion and the bulk volume are in a linear proportional relationship.
In addition, normally, the bulk volume corresponding to 70% homogeneity in consideration of a sufficient safety factor is about 70% of the volume of the solidification container, which is 14% of the solidification container 5 of 200 liters.
It is 0 liters.

An operation example of the pellet solidification processing equipment of this embodiment will be described. Similar to the first embodiment, first, the operating device 16
By operating the input key 16a, the target uniformity is input in advance. Even in this case, the target uniformity is 70
Enter at least%, for example 90%. Along with this, the target bulk volume of about 180 liters corresponding to 90% uniformity is set in the controller 17 from the correlation shown in FIG.
Then, when the selection key 16b of the operation device 16 is operated to select the pellet desired to be solidified, for example, the pellet A among the pellets A, B, and C, the control device 17 starts the driving of the transfer device 7a, and the storage container 1a. The pellet A is transferred to the weighing device 11. The weighing device 11 weighs the weight of the pellets A transferred, and when the weight reaches the reference value, the control device 17 stops the driving of the transfer device 7a, and the weighing device 11 outputs the pellets A of the weighed weight. Kneading tank 6
Be transferred to. The weight at this time is, for example, 50 kg.
Then, the control device 18 obtains the bulk volume of 40 liters of the pellet A corresponding to the weight of 50 kg from the correlation corresponding to the pellet A shown in FIG. 5, and the target bulk volume of 180 liters from the correlation of the solid substance shown in FIG. A target weight of 250 kg of the solid substance S corresponding to 140 liters, which is the difference from the bulk volume of 40 liters of the pellet A, is determined, and 250 kg of the solid substance is weighed by the measuring device 12 and transferred to the kneading tank 6.

In the kneading tank 6, the pellet A and the solid substance S thus transferred to the kneading tank 6 are driven by the driving device 6
The mixture is agitated by the rotary agitating blade 6b connected with a, the valve 20 is opened, and the mixture is put into the solidification container 5. The solidification container 5 charged with the mixture of the pellet A and the solid substance S is the kneading tank 4
Transported to the lower side of 0.

On the other hand, the controller 18 sends data of the weight of the pellet A and the target weight of the solid substance S to the controller 19, and the controller 18 sets the weight of the pellet A to 50 kg and the target weight of the solid substance S to 250 kg. Based on the target weights Wxt and Wyt of the solidifying material (cement) X and the water Y, the weights of the solidifying material and water are measured by the scales 13 and 14 and transferred to the kneading tank 30. In the kneading tank 30, the solidifying material X and the water Y transferred to the kneading tank 30 are driven by a driving device 30a.
Mixing and stirring is performed by the rotary stirring blade 30b connected to the solidification material paste, and the solidification material paste is injected into the solidification container 5 by opening the valve 31. The solidified body obtained by injecting the solidifying material paste into the solidifying container 5 and solidifying was a sound solidified body in which the pellet A and the solid substance S were uniformly dispersed in the solidifying material X as shown in FIG.

As described above, also according to this embodiment, different kinds of waste pellets can be solidified in a state of being uniformly dispersed using the same equipment.

[0075]

According to the present invention, different kinds of waste pellets can be solidified in a uniformly dispersed state using the same equipment.

[Brief description of drawings]

FIG. 1 is a diagram showing a solidification treatment facility for radioactive waste pellets according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a processing function of a control device of the pellet transfer device.

FIG. 3 is a flowchart showing a processing function of a control device of the solid substance transfer device.

FIG. 4 is a diagram showing a correlation between target homogeneity and bulk volume in kneading and solidification.

FIG. 5 is a diagram showing a correlation between the weight and the bulk volume of three types of pellets in a solidification container.

FIG. 6 is a diagram showing a correlation between the weight and the bulk volume of a solid substance (gravel) in a solidification container.

FIG. 7 is a flowchart showing processing functions of a controller for the solidified material transfer device and the water transfer device.

FIG. 8 is a diagram showing a state of a solidified body solidified by the equipment shown in FIG.

FIG. 9 is a diagram showing a solidification treatment facility for radioactive waste pellets according to a second embodiment of the present invention.

FIG. 10 is a diagram showing a correlation between target uniformity and bulk volume in injection solidification.

FIG. 11 is a diagram showing a state of a solidified body solidified by the equipment shown in FIG.

[Explanation of symbols]

 1a to 1c Pellet storage container 2 Solid substance storage container 3 Solidifying material storage container 4 Additive water storage container 5 Solidification container 6 Kneading tank 7a to 7c, 8 Transfer device 9,10 Valve 11 to 14 Metering device 15 Radiation detector 16 Operation Device 16a Target uniformity input key 16b Pellet selection key 17-19 Control device 30 Kneading tank

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Yoshimasa Kiuchi 3-2-2, Saiwaicho, Hitachi-shi, Ibaraki Hitachi Engineering Service Co., Ltd. (72) Inventor, Shozo Matsuda 7-chome, Omika-cho, Hitachi-shi, Ibaraki 2-1 Incorporated company Hitachi Ltd. Energy Research Laboratory (72) Inventor Hidehisa Shiobara 1-3 1-3 Uchisaiwaicho, Chiyoda-ku, Tokyo Tokyo Electric Power Company (72) Inventor Mamoru Tanaka 1-chome, Uchisaiwaicho, Chiyoda-ku, Tokyo No. 1 to 3 in Tokyo Electric Power Company

Claims (20)

[Claims] 1. A radioactive waste pellet solidification treatment facility in which radioactive waste is dried and powdered, and compression-molded pellets are solidified in a solidification container using a solidifying material. A pellet storage container, a solid substance storage container in which a solid substance having the same size as the pellet is stored, the pellet and the solid substance are transferred from the pellet storage container and the solid substance storage container, A first kneading tank for mixing and stirring these into the solidification container; pellet transfer means for measuring and transferring each pellet from the plurality of pellet storage containers to the first kneading tank; Solid substance transfer means for measuring a solid substance from a substance storage container and transferring it to the first kneading tank, and one type of pellet from the different types of pellets And a first transfer control means for controlling the pellet transfer means so that the selected pellet having a predetermined weight is transferred to the first kneading tank, and the pellet selected by the first transfer control means. To obtain a target weight of the solid substance required to uniformly disperse and solidify the solid substance in the solidification container, and to transfer the solid substance of the target weight to the first kneading tank. And a second transfer control unit that controls the transfer unit. 2. The facility for solidifying radioactive waste pellets according to claim 1, wherein the second transfer control means uniformly disperses the pellet weight and the pellets in the solidification container for each of the different types of pellets. A correlation with the weight of the solid substance necessary for solidification is stored, and based on the correlation, the weight of the solid substance corresponding to the pellet of a predetermined weight transferred to the first kneading tank is the solid substance. Solid waste treatment facility for radioactive waste pellets, which is characterized as the target weight of. 3. The facility for solidifying radioactive waste pellets according to claim 1, wherein the second transfer control means determines the weight and bulk volume of the pellets in the solidification container for each of the different types of pellets. One correlation and a second correlation between the solid substance weight and the bulk volume in the solidification container are stored, a first correlation corresponding to the selected pellet is selected, and the first correlation and the second correlation are stored. ,
A predetermined weight of pellets transferred to the first kneading tank,
A facility for solidifying radioactive waste pellets, wherein a target weight of the solid substance is obtained from a target bulk volume required for uniformly dispersing and solidifying the pellets in a solidification container. 4. The solidification facility for radioactive waste pellets according to claim 1, further comprising first operating means for inputting a numerical value of target uniformity of pellet dispersion in the solidification container, and the second transfer. The control means calculates the target weight of the solid substance so that the target uniformity can be obtained, and the solidification facility for radioactive waste pellets is characterized in that: 5. The facility for solidifying radioactive waste pellets according to claim 2 or 3, wherein a numerical value of target uniformity of pellet dispersion in the solidifying container is input.
The second transfer control means further stores a correlation between the pellet dispersion uniformity and the bulk volume in the solidification container, and the second transfer control means stores the correlation based on the correlation and is input by the first operation means. A solid waste treatment facility for radioactive waste pellets, characterized in that a bulk volume corresponding to a target uniformity is determined, and this bulk volume is set as the target bulk volume. 6. The solidification facility for radioactive waste pellets according to claim 1, further comprising second operating means for instructing the selection of any one of the different types of pellets, and the first transfer control means. A facility for solidifying radioactive waste pellets, wherein the type of pellets transferred to the first kneading tank is selected according to a selection signal from the second operating means. 7. The facility for solidifying radioactive waste pellets according to claim 1, wherein the solidifying material storage container and the water storing container respectively contain the solidifying material and the added water, and the solidifying material storage container and the water storing container. A solidifying material and water transfer means for measuring and transferring the solidifying material and water to the first kneading tank, and a predetermined weight of the pellets and a target weight of the solid substance transferred to the first kneading tank. Solidification of radioactive pellets further comprising third transfer control means for controlling the solidification material and water transfer means so that a suitable weight of the solidification material and water are transferred to the first kneading tank. Processing equipment. 8. The solid waste treatment facility for radioactive waste pellets according to claim 7, wherein the target bulk volume is 30% or more of the volume of the solidification container. 9. The facility for solidifying radioactive waste pellets according to claim 1, wherein the solidifying material storage container and the water storing container respectively contain the solidifying material and the added water, and the solidifying material storage container and the water storing container. Second, the solidifying material and the added water are transferred, and they are mixed by stirring and transferred to the solidifying container.
Kneading tank, solidifying material and water transfer means for measuring and transferring the solidifying material and water from the solidifying material storage container and the water storage container, respectively, to the second kneading tank, and transferring to the first kneading tank. Third transfer for controlling the solidifying material and water transfer means so that a predetermined weight of the pellets and a weight suitable for the target weight of the solid substance and water are transferred to the second kneading tank. A facility for solidifying radioactive waste pellets, further comprising a control means. 10. The solid waste treatment facility for radioactive waste pellets according to claim 9, wherein the target bulk volume is 70% or more of the volume of the solidification container. 11. The radioactive waste pellet solidification treatment facility according to claim 1, wherein the first transfer control means measures a surface dose rate of pellets transferred to the first kneading tank. And a means for stopping the transfer of the pellets to the first kneading tank when the surface dose rate obtained by the dose rate detecting means reaches a reference value, for solidifying the radioactive waste pellets. Facility. 12. The facility for solidifying radioactive waste pellets according to claim 11, wherein the second transfer control means inputs the processing data from the first transfer control means, and the surface dose rate is a reference value. Solidification treatment equipment for radioactive waste pellets, wherein the target weight of the solid substance is obtained from the weight of the pellets measured by the pellet transfer means when the temperature reaches the target. 13. The facility for solidifying radioactive waste pellets according to claim 1, wherein the pellet transfer means and the solid material transfer means respectively transfer the pellet and the solid material transferred to the first kneading tank. An apparatus for solidifying radioactive waste pellets, characterized by having a measuring instrument for receiving and measuring the weight in the middle. 14. A method for solidifying radioactive waste pellets, which comprises dry-powdering radioactive waste and compressing and molding the pellets in a solidifying container using a solidifying material, which has the same size as the pellets. Prepare solid material in advance, select one type of pellet from different types of pellets,
Transferring a predetermined weight of the selected pellets to a kneading tank, obtaining the target weight of the solid substance necessary to uniformly disperse and solidify the selected pellets in the solidification container, the target weight of A method for solidifying radioactive waste pellets, comprising transferring a solid substance to the kneading tank, mixing and stirring the pellet and the solid substance in the kneading tank, and charging the mixture into the solidification container. 15. The method of solidifying radioactive waste pellets according to claim 14, wherein the procedure for determining the target weight of the solid substance is to solidify the pellet weight and the pellet preset for each of the different types of pellets. Selecting a first correlation corresponding to the pellets selected from the first correlation with the weight of the solid substance required to be uniformly dispersed and solidified in the container, and transferred to the kneading tank based on the selected first correlation Determining the bulk volume corresponding to the pellet weight, calculating the difference between the target bulk volume required to uniformly disperse and solidify the pellets in the solidification container and the obtained bulk volume, the weight of the solid substance Solidification treatment of radioactive waste pellets, characterized in that the weight of the solid substance corresponding to the difference in bulk volume is determined as a target weight based on a second correlation between Law. 16. The method of solidifying radioactive waste pellets according to claim 14, wherein the solidifying material and the additional water are transferred to the kneading tank together with the pellets and the solid substance, and they are mixed and stirred and then injected into the solidifying container. A method for solidifying radioactive waste pellets, which comprises: 17. The method for solidifying radioactive waste pellets according to claim 16, wherein the target bulk volume is 30% or more of the volume of the solidifying container. 18. The method for solidifying radioactive waste pellets according to claim 15, wherein after the pellets and the solid substance are mixed and stirred, the mixture is poured into the solidification container, and then the solidification material and the added water are added to the solidification container. A method for solidifying radioactive waste pellets, which comprises injecting a kneaded mixture. 19. The method for solidifying radioactive waste pellets according to claim 18, wherein the target bulk volume is 70% or more of the volume of the solidifying container. 20. The method for solidifying radioactive waste pellets according to claim 15, wherein the weight and surface dose rate of the pellets transferred to the kneading tank are measured, and the pellets when the surface dose rate reaches a reference value. A method for solidifying radioactive waste pellets, characterized in that the bulk volume of the pellets is obtained from the weight based on the first correlation.