JPH0249679B2 - HOSHASEIHAIEKINOKOKASHORISOCHI - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention allows liquid or slurry radioactive waste of low, medium, and high levels to be impregnated into a cartridge with good water absorption, and then heated to remove radioactive waste. This invention relates to improvements in devices for immobilizing .

High-level radioactive waste liquid (including slurry liquid)
As a solidification treatment method, the main method currently under research and development is vitrification. In this process, the waste liquid or its concentrate is either directly fed into the melting furnace together with the glass raw material and melted, or it is previously dried and calcined and made into a powder.
It is often supplied into the melting furnace together with the glass raw material. In the former method, the liquid comes into contact with the molten glass surface (1000 to 1100°C) and boils violently, resulting in a large amount of mist and fine powder. These are discharged from the melting furnace along with water vapor and air, causing problems such as a large amount of fine powder depositing in the exhaust gas treatment equipment, causing blockages and increasing radioactivity. Furthermore, a large amount of heat is taken away by the evaporation of the water supplied to the melting furnace, resulting in a problem that the melting ability is reduced. On the other hand, in the latter method,
Dry calcining methods such as a rotary kiln method, a fluidized bed method, and a spray method are used, but all of them produce a large amount of fine powder, causing the same problems as described above, and have the disadvantage that the equipment is complicated.

In addition, as a method of solidifying medium- to low-level radioactive waste liquid (including slurry liquid) generated from nuclear power plants, etc., methods of immobilizing it with asphalt, cement, etc. are currently used, but even more It is also conceivable to use solidified materials produced at high temperatures, such as glass. However, this also causes the same problems as in the solidification treatment of high-level radioactive waste liquid, so the challenge is to develop a method that generates less fine powder.

By the way, as one method of solidification treatment by glass melting, a method using a water-absorbing cartridge made of glass fiber or the like has been proposed (see JP-A-53-17572). The technology disclosed herein involves absorbing radioactive waste into a cartridge, applying microwaves to it in a drying oven to produce a dry product on the cartridge, and then sending the cartridge with the dry product to a melting furnace. and melt it to produce a molten glass material incorporating radioactive waste. In other words, in order to solidify radioactive waste liquid, a melting furnace must be provided in addition to the drying furnace, which has the drawback of making the equipment complex and expensive. Furthermore, in the microwave drying furnace installed before the melting furnace, exhaust gas is discharged in the opposite direction to the direction in which the cartridges are supplied, so that during drying and when melting the cartridges with dried products attached, Another drawback was that the cartridge was likely to become clogged due to the generated dust and the like, making it impossible to smoothly discharge the exhaust gas.

The purpose of the present invention is to eliminate the above-mentioned drawbacks of the conventional technology, and to significantly reduce clogging caused by the generation of fine powder during solidification processes such as melting and sintering of radioactive waste liquids, thereby allowing exhaust gas to be easily and smoothly discharged. It is an object of the present invention to provide an apparatus that can improve the processing capacity and significantly simplify the solidification process and the furnace itself.

The present invention, which can achieve such objects,
A furnace body for heat-treating a material to be treated in which radioactive waste liquid has been absorbed into a water-absorbing cartridge is provided with a cartridge supply pipe, a cartridge extrusion device, a waste liquid supply pipe, an exhaust gas pipe, etc., and the exhaust gas pipe is attached to the furnace body. This is a radioactive waste liquid solidification treatment device that is connected to the top of the radioactive waste liquid.

Hereinafter, the present invention will be explained in more detail based on the drawings. FIG. 1 is an explanatory diagram showing one embodiment of the present invention. This apparatus includes a furnace body 1 that heats and melts a workpiece in which radioactive waste liquid has been absorbed into a water-absorbing cartridge made of glass raw material, and a workpiece supply path 2 that communicates with the upper side of the furnace body 1 and extends approximately horizontally. , a cartridge supply pipe 3 and a cartridge extrusion device 4 located on the proximal end side of the workpiece supply path 2 , a waste liquid supply pipe 5 connected to an intermediate portion of the workpiece supply path 2 , and a furnace main body 1 . Exhaust gas pipe 6 connected to the top
and a microwave waveguide 7. The cartridge 8 sent from a cartridge supply device (not shown) is a cylindrical aggregate of fibers with good water absorption properties wrapped around a sheet-like material such as glass fiber. It has a composition determined from the glass composition. This cartridge 8
is sent to the workpiece supply path 2 through the cartridge supply piping 3, and is sent out horizontally along the workpiece supply path 2 by the cartridge extrusion device 4. The radioactive waste liquid (including slurry liquid containing a large amount of fine particles, etc.) sent from the waste liquid supply system through the waste liquid supply pipe 5 does not seep into the cartridge 8 that has reached the position directly below the waste liquid supply pipe 5. It is soaked to a certain degree and becomes the object to be processed 9. Thereafter, the cartridge is fed into the furnace body 1 by the cartridge extrusion device 4, and is heated and melted by microwaves applied from a microwave oscillator (not shown) through the microwave waveguide 7. . The exhaust gas generated at this time is supplied to an exhaust gas treatment system (not shown) through the exhaust gas pipe 6 and is treated there. The molten material produced within the furnace body 1 is taken out of the furnace body 1 through a glass extraction nozzle 10 formed at the bottom thereof. With such a device, nonvolatile components such as nuclear fission products, actinide elements, and heavy metal elements contained in the waste liquid can be immobilized. In addition, since the cartridge itself utilizes the overeffect of allowing gases such as water vapor and generated gases to pass through, but not fine powder, the generation of dust within the furnace body is extremely small, and there is no possibility that fine powder will be scattered or entrained in the exhaust gas. Since the waste can be kept extremely low, and the material to be treated can be dried and melted within a single furnace, the radioactive waste liquid treatment process and the furnace itself can be simplified, making exhaust gas treatment extremely easy. I can do it. In addition, if microwaves are used to heat the cartridge (workpiece) after soaking with waste liquid as in this example, heating can be done from inside the cartridge, which not only greatly reduces the time required for melting, but also The device can be extremely simplified.

The structure and dimensions of the cartridge may be appropriately determined by taking into consideration the necessary basic performance conditions, ie, water absorption and excess performance, as well as ease of handling. When microwaves are used as a heating means, in order to prevent the microwaves from leaking from the cartridge supply system, for example, in the case of a cylindrical cartridge, the diameter of the cartridge should be approximately
It is desirable that it be about 10cm or less. Further, the composition of the cartridge may be appropriately selected depending on the type of the intended solidified material.

FIG. 2 shows another embodiment of the invention. In this embodiment, in addition to microwave heating, direct energization type Joule heating is used. An electrode 11 is formed inside and below the furnace body 1, and the glass is melted mainly by direct energization, with supplementary heating using microwaves. Of course, in this case, it is also possible to melt the cartridge simply by heat transfer or radiation from the molten glass without using microwaves. Incidentally, since the other configurations are the same as those in FIG. 1, corresponding parts are given the same reference numerals and description thereof will be omitted.

By the way, as a result of dropping a cartridge impregnated with a simulated radioactive waste liquid into a glass melting device as shown in Figure 2 and examining the state in which it was heated and melted, we found that:
It became clear that the simulated liquid gradually melted without seeping out. It was also confirmed that the generation of fine powder was extremely small.

Note that the present invention can also be applied to cases other than the vitrification treatment described above. If the workpiece is heated while being pressurized by the press piston in the furnace main body, a sintered body can be produced without generating a large amount of fine powder.

The present invention is a solidification treatment apparatus for radioactive waste liquid constructed as described above, in which a furnace body for heat-treating objects to be treated is integrated with a feed passage for objects to be processed, a cartridge supply pipe, a cartridge extrusion device, a waste liquid supply pipe, etc. Moreover, since only one furnace is required for drying and melting, the structure of the device is very simple, and instead of cartridges with dried products attached, cartridges soaked with waste liquid are placed in the furnace main body. Since the exhaust gas pipe is directly connected to the upper part of the furnace body, the exhaust gas can be treated smoothly and easily, and the overall solidification process can be significantly simplified. It is something that can be played.

[Brief explanation of drawings]

FIG. 1 is an explanatory diagram showing one embodiment of the solidification processing apparatus according to the present invention, and FIG. 2 is an explanatory diagram showing another embodiment of the present invention. 1... Furnace body, 2... Processing material supply path, 3...
Cartridge supply piping, 4... Cartridge extrusion device, 5... Waste liquid supply piping, 6... Exhaust gas pipe, 7
...Microwave waveguide, 8...Cartridge, 9
...Workpiece, 10...Glass extraction nozzle.

Claims (1)

[Claims] 1. A furnace body for heat-treating a workpiece in which radioactive waste liquid has been absorbed into a water-absorbing cartridge, a workpiece supply path that communicates with the upper part of the furnace body and extends approximately horizontally, and a base of the workpiece supply path. A cartridge supply pipe and a cartridge extrusion device located on the end side,
A radioactive waste liquid solidification processing apparatus comprising a waste liquid supply pipe connected to an intermediate portion of a processing material supply path and an exhaust gas pipe connected to an upper part of a furnace main body.