JP3115141B2 - Radioactive waste cement solidification method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radioactive fixed waste treatment method for solidifying radioactive waste generated in a nuclear power plant or the like with cement.

[0002]

2. Description of the Related Art A prior art of this type of radioactive waste cement solidification method and apparatus will be described with reference to FIG.

A waste container 1 containing liquid radioactive waste and a cement container 2 containing powdered cement are provided, and these containers 1 and 2 are connected to a kneading device 5 via transfer pipes 3 and 4. Have been. The kneading device 5 has a stirrer 6,
Also, a scale (not shown) and the like are provided.

The radioactive waste and the cement are kneaded in the kneading device 5 to form a cement paste, and the cement paste sent from the kneading device 5 is sent to a drum 7 and solidified.

[0005] In the case of solid radioactive waste, although not shown, a cement container containing powder cement and a water container containing water for cement kneading are provided. The cement and the water are kneaded by a kneading device connected to the cement paste to form a cement paste.
Then, the cement-cement paste is sent out together with the solid radioactive waste to a drum and solidified.

[0006]

In the prior art, after the cement paste is filled from the kneading device 5 into the drum 7 to form a solidified body, solidification of the cement paste remaining in the kneading device 5 is prevented. FIG. 4
As shown in the figure, a cleaning water supply device 8 for supplying cleaning water to the kneading device 5 and a cleaning waste liquid treatment device 9 for receiving cleaning water from the kneading device 5 are connected.

[0007] Every time the solidification is completed, the cleaning water is supplied from the cleaning water supply device 8 to the kneading device 5 to perform the cleaning, and then the waste liquid is processed by the cleaning liquid processing device 9 or the drum can is processed. At 7, the waste liquid is received and a new solidified body is prepared.

For this reason, a washing operation is required for each cement filling operation, and there is a problem that a large amount of washing waste liquid is generated. Further, depending on the composition of the waste liquid, the hydration reaction of the cement is accelerated, and the cement may harden very quickly, and there is a problem that it is necessary to monitor the state of the cement paste in the kneading apparatus.

The present invention has been made in view of such circumstances, and it is possible to appropriately control the solidification reaction time of cement, thereby reducing the necessity of cleaning and eliminating the need for monitoring. The aim is to provide a method.

[0010]

According to the first aspect of the present invention, there is provided a waste container containing liquid radioactive waste, a cement container containing powdered cement, and A kneading device connected via a transfer pipe to knead the radioactive waste and cement into a cement paste, a drum can for filling and solidifying the cement paste delivered from the kneading device, and a cement paste in the kneading device In the radioactive waste cement solidification method using a solidification treatment device having a temperature control device for controlling the temperature, while setting the temperature at the time of kneading the cement paste to 25 ° C. or less, when filling the drum can The temperature of the cement paste is 15-40
C., and solidification of radioactive waste cement, wherein the temperature in the solidification device until the remaining cement paste in the kneading device solidifies after the cement paste is filled in the drum can is kept at 0-5 ° C. Provide a way.

According to the second aspect of the present invention, a cement container containing powder cement, a water container containing water for cement kneading, and these containers are connected via a transfer pipe to knead the cement and water. A kneading device for forming a cement paste, a drum can for filling and solidifying the cement paste sent out from the kneading device together with solid radioactive waste, and a temperature control device for controlling a cement paste temperature in the kneading device. In the method for solidifying radioactive waste cement using a solidification treatment device, the temperature at the time of kneading the cement paste is set to 25 ° C. or less, and the temperature of the cement paste at the time of filling the drum can is set to 15 to 40 ° C. After the cement paste is filled into the drum, the remaining cement paste in the kneading device is solidified until it solidifies. The temperature in the apparatus to provide a radioactive waste cementation process wherein the holding to 0 ° C. to 5 ° C..

[0012]

According to the study by the inventors, the solidification time of the cement paste varies greatly depending on the temperature conditions. For example, 40 ° C
Solidifies in about 1 to 3 hours, and at 20 ° C. in about 7 to 8 hours. At 5 ° C. or less, it takes 20 hours or more to solidify.

Therefore, if the temperature of the cement paste is controlled, for example, the temperature is set to a low solidification rate at the time of kneading cement, the temperature is set to a high solidification rate at the time of filling and solidification, and the remaining cement paste is set after filling. Can be set to a temperature that does not solidify until the next operation.

According to the first or second aspect of the present invention, the temperature control device for controlling the temperature of the cement paste in the kneading device is provided so that the solidification reaction time of the cement can be appropriately controlled. By setting the temperature at which the paste does not solidify until the next operation, it is possible to reduce the necessity of cleaning and the necessity of monitoring as in the conventional case.

By setting the temperature at the time of kneading the cement paste to 25 ° C. or less, the ordinary day shift time is regarded as 7 to 8 hours, and the cement paste can be prevented from solidifying within that time. Further, the temperature of the cement paste at the time of filling the drum can is 15 to
By setting the temperature at 40 ° C., the time required for temporary storage of the cement-filled drum can be considered. That is, the cement in the drum must be sufficiently solidified in order to move the cement-filled drum to the solid waste storage. If the solidification time is long, a temporary storage space for the cement-filled drum can is required widely. Therefore, if the solidification is performed in a short time, the temporary storage space can be reduced. The temperature for the temporary storage is about 1 to 7 hours.
According to the present invention, monitoring can be effectively eliminated.

Further, since the temperature of the remaining cement paste in the kneading apparatus is maintained at 0 ° C. to 5 ° C., for example, in a standby state until the filling operation of one day is completed and the operation is resumed the next day, 24 so that there is no need to clean the equipment
The cement paste can be prevented from solidifying for more than an hour. According to the present invention, the necessity of cleaning can be reduced.

[0017]

Embodiments of the present invention will be described below with reference to the drawings.

FIG. 1 shows an embodiment, and is a system diagram of a radioactive waste cement solidification treatment apparatus.

As shown in FIG. 1, in this embodiment, a waste container 11 for containing liquid radioactive waste (hereinafter, referred to as radioactive waste in this embodiment) is provided. Radioactive liquid waste generated in the plant is stored.

Further, a cement container 12 is provided, and the cement container 12 has powder cement kneaded with an admixture,
For example, powdered Portland cement is stored.

Each of the containers 11 and 12 has a transfer pipe 1
The kneading device 15 is connected via 3 and 14. The kneading device 15 is provided with a stirrer 16 and a measuring device (not shown). The radioactive waste liquid and the cement are kneaded in the kneading device 15 to form a cement paste, and the cement paste delivered from the kneading device 15 is supplied to the drum 17.
And solidified.

In this embodiment, a temperature control device 18 for controlling the temperature of the cement paste in the kneading device 15 is provided. The temperature control device 18 includes a thermometer 19 for measuring the temperature of the cement paste to be stirred, a heat exchanger 20 for heating and cooling the paste, and a heat exchanger 2 for heating and cooling the paste.
And a controller 21 for controlling the refrigerant to zero. When there is a difference between the temperature measured by the thermometer 19 and the set value, the refrigerant is sent from the controller 21 to the heat exchanger 20, and the temperature is controlled.

Next, the solidification method will be described with reference to FIG. The figure shows the relationship data between the cement paste temperature and the solidification time. The horizontal axis indicates the cement paste temperature (° C) and the solidification time (H
r) is represented on the vertical axis.

As is clear from the characteristic curve A shown in FIG. 2, at 0 to 5 ° C., the solidification time is very long, and is longer than 24 hours. In the range of 5 to 25 ° C., the solidification time is about 8 to 24. Further, in the range of 25 to 40 ° C., the time is reduced to about 1 to 7 hours.

In the present embodiment, the kneading temperature of the cement paste in the kneading device 15 is
The following settings were made to prevent solidification within 7 hours.
In addition, the temperature of the cement paste at the time of filling the drum 17 was set at 15 to 40 ° C. to increase the solidification rate.
Further, after filling the drum 17 with the cement paste, the temperature of the remaining cement paste in the kneading device 15 is reduced to 0.
C. to 5 DEG C., so as not to solidify within 24 hours.

According to the present embodiment, the temperature at the time of kneading the cement paste is set to 25 ° C. or less, so that the cement paste does not solidify within the normal day shift time (7 to 8 hours). Monitoring became unnecessary. In addition, since the temperature of the cement paste at the time of filling into the drum 17 is set to 15 to 40 ° C., the solidification speed in the drum 17 is increased, the temporary storage space of the drum 17 can be reduced, and the temporary storage of the drum 17 is reasonable. I got space. Furthermore, since the temperature of the remaining cement paste in the kneading device 15 is maintained at 0 ° C. to 5 ° C., the kneading device 15 is washed in a standby state until the filling operation of one day is completed and the operation is resumed the next day. Need can be reduced,
The time required for the cleaning process can be greatly reduced.

FIG. 3 shows another embodiment of the present invention, and is a system diagram of an apparatus suitable for solidifying solid radioactive waste with cement.

In this embodiment, in order to solidify the solid radioactive waste with cement, the waste storage container 1 of the above embodiment is used.
In place of 1, a water container 22 for containing water for cement kneading is provided. In the kneading device 15, the water supplied from the water container 22 and the powder cement supplied from the cement container 12 are kneaded. Then, together with the cement paste sent from the kneading device 15, the solid radioactive waste 2
3 is filled in the drum 17 and solidified.

In this embodiment, the kneading device 1
Temperature control device 1 for controlling the cement paste temperature in 5
8 are provided. The configuration of the temperature control device 18, the configuration of other components, and the operation such as temperature setting are substantially the same as those in the above-described embodiment, and therefore, the same reference numerals as in FIG. I do.

According to this embodiment, similarly to the above-described embodiment, the solidification reaction time of the cement can be appropriately controlled, whereby the necessity of cleaning and the need for monitoring can be reduced.

[0031]

As described above, according to the present invention,
As the solidification treatment of liquid or solid radioactive waste, the temperature during kneading of cement paste, the temperature in the drum, and the temperature in the kneading device for the residue are properly controlled to optimize the solidification reaction time of cement. , The labor required for the cleaning process can be reduced.

[Brief description of the drawings]

FIG. 1 is a diagram showing one embodiment of a radioactive waste cement solidification treatment apparatus according to the present invention.

FIG. 2 is a view showing a method of solidifying radioactive waste cement by the apparatus of the embodiment.

FIG. 3 is a diagram showing another embodiment of the present invention.

FIG. 4 is a diagram showing a conventional example.

[Explanation of symbols]

 Reference Signs List 11 waste container 12 cement container 13, 14 transfer pipe 15 kneading device 17 drum can 18 temperature control device 22 water container 23 solid radioactive waste

Continuation of front page (56) References JP-A-60-86497 (JP, A) JP-A-2-162298 (JP, A) JP-A-54-136000 (JP, A) JP-A-3-29898 (JP) , A) (58) Field surveyed (Int.Cl. ⁷ , DB name) G21F 9/16 G21F 9/30

Claims (2)

(57) [Claims] 1. A waste container containing liquid radioactive waste, a cement container containing powdered cement, connected to each of these containers via a transfer pipe, and kneading the radioactive waste and cement. Radioactive waste using a solidification treatment device comprising a kneading device for cement paste, a drum for filling and solidifying the cement paste sent from the kneading device, and a temperature control device for controlling the temperature of the cement paste in the kneading device. In the cement solidification method, the temperature at the time of kneading the cement paste is set to 25.
° C or less, and the temperature of the cement paste at the time of filling into the drum can is set to 15 to 40 ° C, and the cement paste in the kneading device after the cement paste is filled into the drum can is solidified until the remaining cement paste solidifies. A method for solidifying a radioactive waste cement, wherein the temperature of the cement is maintained at 0 ° C to 5 ° C. 2. A cement container for accommodating powdered cement, a water container for accommodating water for cement kneading, and connected to each of these containers via a transfer pipe to knead the cement and water to form a cement paste. A kneading device, a drum can for filling and solidifying the cement paste delivered from the kneading device together with solid radioactive waste, and a solidification treatment device comprising a temperature control device for controlling the cement paste temperature in the kneading device. In the method for solidifying radioactive waste cement, the temperature at the time of kneading the cement paste is set to 25 ° C. or less, and the temperature of the cement paste at the time of filling the drum can is 15 to
Radioactive waste cement solidification, wherein the temperature in the solidifying device is set at 0 ° C to 5 ° C until the remaining cement paste in the kneading device solidifies after setting the cement paste in a drum can at 40 ° C. Processing method.