JPH03199999A - Cartridge for treating radioactive waste fluid - Google Patents

Abstract

PURPOSE:To sufficiently secure the amount of glass even when a glass raw material is not replenished from a separate supply source when radioactive waste fluid is infiltrated to be melted under heating by embedding a glass extender in a glass fiber. CONSTITUTION:A glass extender is selected from a group consisting of inorg. compounds becoming vitreous by heating and melting, for example, a glass marble 18 or glass beads. The wt. ratio of the glass fiber 11 and glass extender in a cartridge is set to the range of about 1:0.1 - 4 and the density of the glass fiber 11 is set to about 100 - 400 kg/cm<3>. Further, the glass extender is pref. welded to the glass fiber 11. As the glass fiber 11, a glass staple fiber is suitable and the mean diameter of the glass fiber 11 is set to about 8 - 50 mum. The glass extender is included in the glass fiber to fill a mold and the whole is heated to partially weld the glass extender and the glass fiber to mold a cartridge for treating radioactive waste fluid.

Description

DETAILED DESCRIPTION OF THE INVENTION "Industrial Application Field" The present invention relates to a radioactive waste liquid treatment cartridge used to impregnate radioactive waste liquid, heat it, melt it, and vitrify it when disposing of radioactive waste liquid. .

"Prior Art" When spent fuel used in nuclear power generation is reprocessed in a reprocessing plant, a high-level radioactive waste liquid containing nitric acid containing uranium, transuranic elements, and fission products is produced as a by-product. Therefore, a technology for safely and efficiently disposing of such radioactive waste liquid is desired.

Conventionally, to process this radioactive waste liquid, the radioactive waste liquid is either directly or denitrified and concentrated to form a slurry, mixed with glass raw materials and supplied to a high-temperature glass melting furnace, where the liquid components in the waste liquid are evaporated. At the same time, a technology has been developed in which radioactive substances are melted into glass, and the molten glass is poured into a stainless steel container and solidified.

In such waste liquid treatment technology, when the waste liquid boils violently in the glass melting furnace, dust containing a large amount of radioactive substances is generated and flows out along with the exhaust gas, so it is impossible to prevent this dust from scattering. becomes important.

The present applicants have already proposed a technique in which a cartridge formed by partially fusing glass fibers is impregnated with the radioactive waste liquid and heated and melted to solidify it into glass (Japanese Patent Laid-Open No. 60-244899). , Japanese Patent Publication No. 62222198).

The use of this cartridge has the advantage of preventing the generation of dust during heating and melting and making it easy to handle.

The above cartridge preferably has a density of 170 kg/m3 or more in order to obtain sufficient compressive strength, and
It is said that a density of 230 kg/m'' or less is preferable in order to prevent a decrease in drop strength (see page 8 of the specification of JP-A-60-244899).

However, if the size of the glass melting furnace is increased and the amount of radioactive waste liquid to be treated is increased, the amount of glass required will naturally increase. In order to secure this amount of glass, it is sufficient to supply more cartridges, but this poses a problem in that the volume of the cartridge increases significantly.

Therefore, it is conceivable to separately add glass raw materials such as glass beads to make up for the shortage of glass together with the cartridge. However, the cartridge and the glass raw material are separately supplied to the waste liquid treatment equipment, which complicates the supply system. Further, by adding a glass raw material separately, there is a possibility that the generation of dust will increase.

[Problems to be Solved by the Invention] The present invention has been made in view of the problems of the prior art described above, and its purpose is to obtain glass raw material from another source when impregnating radioactive waste liquid and heating and melting it. To provide a cartridge for treating radioactive waste liquid that can secure a sufficient amount of glass without replenishing it.

[Means for Solving the Problems] The present invention provides a cartridge for radioactive waste liquid treatment in which glass fibers are partially heat-fused and formed into a block shape, in which a glass filler is embedded in the glass fibers. It is characterized by

"Operation" By burying the glass filler as described above, when impregnating radioactive waste liquid and heating and melting it, radioactive materials can be safely vitrified without replenishing glass raw materials from another source. The required amount of glass can be secured. As a result, the supply system to the waste liquid treatment equipment is unified, and safety can be improved. Further, it is possible to prevent an increase in the generation of dust due to the introduction of another glass raw material.

Further, since the glass filler is embedded in the glass fiber, the glass fiber acts as a buffering material in the event of an impact, and the drop strength can be minimized.

Furthermore, leakage of the glass filler during handling is also prevented.

[Preferred Embodiment of the Invention] In the present invention, the glass extender includes, for example, glass marble, glass beads, glass cullet, glass rod,
At least one selected from the group consisting of glass lumps, glass flakes, and inorganic compounds that can be vitrified by heating and melting can be preferably used.

Since all of these glass fillers have a higher density than glass fibers, the required amount of glass can be secured without significantly increasing the volume of the cartridge.

In addition, inorganic compounds that can be heated and melted to become vitrified include:
For example, B, Si, Li, Ba, Ca, Zn,
A1. Nitrates, sulfates, carbonates, and phosphates of glass constituent elements such as Na, K, and Mg, or inorganic acids of the above-mentioned glass constituent elements can be freely used.

Furthermore, when radioactive materials are vitrified and disposed of, in order to prevent leakage of the radioactive materials as safely as possible, it is required that the glass composition when the radioactive materials are solidified be constant. Therefore, it is preferable to determine the respective compositions and blending ratios in advance so that when glass fibers and glass extenders are heated and melted to vitrify, the final composition is constant.

The weight ratio of glass fiber and glass filler in the cartridge is preferably 0.1 to 4, and I:0.
．． More preferably, it is 5-2. If the ratio of glass filler is less than 0.1 to 1 glass fiber, it will not be possible to secure the amount of glass necessary to vitrify the radioactive material, and if it exceeds 4, the overall weight will increase. There is a possibility that sufficient drop strength etc. cannot be obtained.

In addition, the density of glass fiber is 100 to 400 kg/+
It is preferable that the density is 100 kg/m
If it is less than 3, sufficient compressive strength cannot be obtained, and 400 kg
/m3, it becomes easy to break and the drop strength decreases.
Moreover, the gaps between the glass fibers become relatively small, and the water retention rate decreases.

Furthermore, it is preferable that the glass extender is heat-fused to the glass fiber. This allows the glass filler to be firmly held in the glass fibers, preventing it from leaking out during handling or reducing the strength of the cartridge.

The method for manufacturing a cartridge for radioactive waste liquid treatment of the present invention includes:
Although not particularly limited, it can be manufactured, for example, as follows.

The glass fibers may be either short fibers or long fibers, but short fibers are particularly suitable. The average diameter of glass fiber is 8
~50 μm is preferred. If the average diameter is less than 8 μm, good water absorption cannot be obtained. Also, the average diameter is 50μ
If it exceeds m, the productivity in the spinning process will deteriorate, and the number of points where the glass fibers will be fused to each other will decrease, making it easy to lose the shape.

The glass fibers may be provided with a binder selected from inorganic acids, inorganic salts, organic silanes, oil emulsions, silicic acid sols, alumina sols, and the like.

These binders have adhesive and film-forming effects on the glass fibers, thereby increasing the compressive and impact strength of the cartridge. Note that these binders may be applied after the cartridge is formed. As a method for applying the binder, preferably employed is a method in which the binder is made into a solution such as an aqueous solution, and glass fibers or a molded cartridge are immersed in the solution, or the solution is spray-coated. Inorganic acids and salts as binders include:
Sodium silicate, sodium borate, sodium nitrate, sodium sulfate, sodium carbonate, potassium silicate,
Potassium borate, potassium nitrate, potassium sulfate, potassium carbonate, boric acid, silicic acid, lithium borate, lithium silicate, zinc borate, zinc silicate, etc. can be used. Further, as the organic silane, for example, γ-alkylaminotriethoxysilane can be used, and as the oil emulsion, for example, an emulsified product of mineral acid oil or the like can be used.

Next, the above-mentioned glass filler is incorporated into the glass fibers, filled into a mold, and heated to partially fuse them to form a cartridge. At this time, it is preferable to adjust the filling amount so that the density of the glass fibers falls within the above-mentioned range.

Further, it is preferable that the weight ratio of glass fiber and glass extender is also within the above-mentioned range. The method of incorporating the glass extender into the glass fiber is not particularly limited, but for example, the method may include placing the glass extender in the center of the glass fiber,
Alternatively, a glass filler may be dispersed and mixed into glass fibers.

The shape of the radioactive waste liquid processing cartridge of the present invention may be any shape, such as spherical, cylindrical, or rectangular parallelepiped, but it should be made easy to roll when introduced into processing equipment to prevent damage or clogging of the cartridge. Therefore, spherical and cylindrical shapes are particularly preferred.

“Embodiments of the Invention” First, the manufacturing process of the cartridge of the present invention will be explained in the first to
This will be explained with reference to FIG.

As shown in FIG. 3, the fiberized glass fiber 11 is
It is deposited and conveyed on a belt conveyor 12, 13. In the process, the device 14 impregnates the glass fibers 11 with a binder solution. This dobu-soaking device 14 is
The binder solution overflowing from the supply pipe 14a is impregnated into the glass fibers 1.1 via the roller 14b. Alternatively, the glass fibers 11 may be impregnated with a binder solution by spraying 15. In addition, after impregnating with the solution, it is preferable to remove the solvent such as water by heating and drying.

After the glass fibers 11 are thus impregnated with the binder solution, a predetermined amount of the glass fibers 11 are rolled and filled into a metal mold 16, 17, as shown in FIG. At this time, a glass marble 18 is embedded in the center of the glass fiber 11.

Of course, other glass fillers such as those described above may be used in place of the glass marble 18.

After the glass fibers 11 are filled into the mold 16.17 in this way, they are heated at 580±25° C. for about 30±5 minutes to partially fuse the glass fibers 11. At this time, the glass fiber 11 is also fused to the surface of the glass marble 18, and a cylindrical cartridge in which the glass fiber 11 and the glass marble 18 are integrated is formed.

Figure 1 shows the cartridge thus formed taken out and cut in half lengthwise. The cartridge I9 has a cylindrical shape as a whole, and is made of glass fibers 11 with a glass marble 18 embedded in the center.

Experimental Example A boric acid aqueous solution was applied as a binder to 50 g of glass fiber, and a ball with a diameter of 25 mm (weight 20 g) and a ball of 30 mm (
A glass marble weighing 34g and 1.35mm (weight 55g) was embedded and filled into a mold, and baked at 550°C for 30 minutes to produce a cartridge. In addition, for comparison, a cartridge made of only glass fiber without embedded glass marble was manufactured in the same manner. The internal volume of the mold used was 260 cm3. Furthermore, the glass compositions of the glass fibers and glass marbles used are as shown in Table 1.

(Hereinafter, blank spaces) Table 1 Each of the cartridges thus obtained was impregnated with water, and the maximum amount of liquid retained was measured. The results are shown in Table 2.

As shown in Table 2, it can be seen that the amount of liquid retained does not decrease significantly even when the weight of the cartridge is approximately doubled.

Furthermore, all of these cartridges had sufficient compressive strength and drop strength.

"Effects of the Invention" As explained above, according to the present invention, since the glass extender is buried, there is no need to replenish the glass raw material from another source when impregnating radioactive waste liquid and heating and melting it. It is also possible to secure the amount of glass necessary to safely vitrify radioactive materials. As a result, the supply system to the waste liquid treatment equipment is unified, and safety can be improved. Further, it is possible to prevent an increase in the generation of dust due to the introduction of another glass raw material.

[Brief explanation of drawings]

FIG. 1 is a perspective view of a radioactive waste liquid treatment cartridge according to an embodiment of the present invention cut vertically, FIG. 2 is a perspective view showing the process of filling glass fibers and glass marble into a mold, and FIG. FIG. 3 is a perspective view showing a step of impregnating glass fibers with a binder solution. In the figure, 11 is glass fiber, 16 and 17 are molds, 18 is glass marble, and 19 is a cartridge for treating radioactive waste liquid.

Claims (5)

[Claims] (1) A cartridge for radioactive waste liquid treatment comprising glass fibers partially heat-fused and formed into a block shape, characterized in that a glass filler is embedded in the glass fibers. . (2) The glass extender is at least one member selected from the group consisting of glass marble, glass beads, glass cullet, glass rods, glass lumps, glass flakes, and inorganic compounds that are vitrified by being melted by heating. 1. The cartridge for treating radioactive waste liquid according to 1. (3) The cartridge for radioactive waste liquid treatment according to claim 1 or 2, wherein the weight ratio of the glass fiber to the glass filler is 1:0.1 to 4. (4) The density of the glass fiber is 100 to 400 kg/m
The cartridge for radioactive waste liquid treatment according to claim 1, 2 or 3, wherein: ^3. (5) The cartridge for radioactive waste liquid treatment according to claim 1, 2, 3, or 4, wherein the glass filler is heat-fused to the glass fiber.