JPH053920B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] This invention relates to an in-rock storage facility for radioactive waste.

[Conventional technology]

High-level radioactive waste generated during the process of reprocessing spent nuclear fuel has high radioactivity over a long period of time and also has a large calorific value.
Therefore, before final disposal to isolate it from the human environment, we must first take sufficient safety measures such as vitrification, and then store and manage it for a certain period of time to reduce its radioactivity and calorific value. It is necessary to sufficiently attenuate the The storage and management of this radioactive waste is for a long period of time, ranging from several decades to several hundred years.
Facilities for this purpose are required to be able to keep the radioactive waste in good health during that period, and to be able to cool the radioactive waste and attenuate its radioactivity without causing negative effects such as radioactive contamination on the surrounding environment. Ru.

Facilities for storing such radioactive waste are currently being considered to be built in structures built above or semi-above ground, and those built underground in bedrock. Among these, those installed in underground bedrock are intended to use stable rock as the structural framework, and the facility must have sufficient durability and be resistant to natural impacts (earthquakes, volcanic activity, etc.) and social impacts. It is said to be particularly advantageous as a long-term storage facility because it can withstand high temperatures, has excellent radiation shielding performance, and has sufficient cooling capacity.

[Problem that the invention seeks to solve]

However, the above-mentioned storage facility in underground rock is still just a concept, and the specific equipment method, especially the storage system that can efficiently cool the radioactive waste without compromising its integrity, is still unclear. No facilities were provided, and it was desired that such storage facilities be provided.

This invention was made in view of the above circumstances, and an object of the present invention is to provide an in-rock storage facility that can efficiently cool and store radioactive waste without impairing its integrity.

[Means for solving problems]

This invention provides a shaft whose upper end is open to the atmosphere, and a storage shaft whose one end is connected to the lower end of the shaft and whose other end is open to the atmosphere, and air flows through the shaft. and storing radioactive waste in a storage shaft, the shaft having a vertical part leading to the open end, a side part extending laterally at the lower end of the vertical part, and a side part and the storage shaft having a vertical part leading to the open end, a side part extending laterally at the lower end of the vertical part, A drainage tunnel is connected to the lower end of the vertical section to drain water from the vertical section.

[Effect]

In this invention, the storage shaft and the shaft become a series of air flow paths, and the shaft creates a natural draft (due to the so-called chimney effect) due to the temperature difference between the air inside and outside the shaft, and the air inside the shaft is ventilated. to cool radioactive waste.

In addition, if water such as rainwater infiltrates from the open end of the upper end of the shaft, this water will fall down the vertical part and be discharged from the lower end into the drainage tunnel, so this water will not reach the storage shaft and will be radioactive. There is no risk of water coming into contact with the waste and damaging its integrity.

〔Example〕

Embodiments of the present invention will be described below with reference to FIGS. 1 and 2.

FIG. 1 is a diagram showing an overall schematic configuration of the storage facility A of this embodiment when it is installed on a mountainside, and reference numeral 1 in the figure is a rock forming the slope of the mountain.
A storage tunnel 2 is excavated within this bedrock 1.
The storage tunnel 2 is composed of a lower shaft 2a, an upper shaft 2b, which are substantially parallel to each other, and a storage shaft 2c, which is substantially vertical, and which communicates the shafts 2a, 2b. One end of the lower shaft 2a is open to the atmosphere on the ground surface, and a door 3 is provided in the middle of the upper shaft 2b.
is normally closed. Also storage shaft 2c
There is solidified radioactive waste package 4 inside...
...is stored. The solidified package 4... is
Radioactive waste is vitrified and then sealed in a stainless steel container (canister), which generates a high amount of heat due to the decay heat of the radioactive waste. The solidified substance packages 4 are housed in the storage shaft 2c with a gap so that air can circulate around them. Further, although not shown in the drawings, radiation shielding materials are attached to the upper and lower ends of the storage shaft 2c to allow air to flow therethrough but to block radiation.

One end of the upper shaft 2b is connected to the lower end of the vertical shaft 5. The shaft shaft 5 extends vertically within the rock mass 1, its upper end is open to the atmosphere, and its open end 5a is connected to the lower surface of an exhaust tower 6 provided on the ground surface. The exhaust tower 6 is covered by the open end 5a of the shaft shaft 5, and a louver 7 is attached around the side surface of the exhaust tower 6.

Further, the shaft shaft 5 has a vertical portion 5b formed almost vertically at its upper part, a side portion 5c extending laterally from the side surface of the lower end of the vertical portion 5b, and a side portion 5c extending laterally from the side surface of the lower end of the vertical portion 5b, and one end of the side portion 5c. It extends downward and has a connecting portion 5d at its lower end to which the upper tunnel 2b of the storage tunnel 2 is connected. One end of a drainage tunnel 8 is connected to the lower end of the vertical portion 5b of the shaft 5. This drainage tunnel 8 has a downward slope toward the ground surface, and its tip is open at the ground surface.

Based on the above configuration, this storage facility A can store solidified material packages 4 (radioactive waste) for a long period of time without adversely affecting the ground surface due to the excellent radiation shielding performance of the stable rock 1. At the same time, the stored solidified material packages 4 are cooled by ventilation using natural drafts. That is, storage shaft 2 (lower shaft 2a, storage shaft 2
c, upper shaft 2b) and vertical shaft 5 (connection part 5
d, the side part 5c, and the vertical part 5b) become a series of air flow paths, and by the natural wind force generated by the shaft 5,
The air in the shaft 5 rises and is discharged into the atmosphere from the upper open end 5a through the louver 7 of the exhaust tower 6, and along with this, outside air flows in from the open end of the lower shaft shaft 2a. Then, this outside air is stored in the storage shaft 2.
The solidified material package 4 in c is cooled by flowing around it. (The solid line arrow in Fig. 1 indicates the direction in which this air flows.) In addition, in this storage facility A, rainwater does not enter from the shaft 5, and there is no risk that the solidified material package 4 will come into contact with rainwater. do not have. That is, since the upper open end 5a of the shaft 5 is covered by the exhaust tower 6 as described above, rainwater does not enter through the open end 5a during normal rainfall. Furthermore, even if rainwater were to enter through the louvers 7 of the exhaust tower 6 during heavy rain or storms, the rainwater would fall within the vertical section 5b of the shaft 5 and flow down through the drainage tunnel 8 from its lower end to the ground. discharged to the surface. (The dashed arrows in FIG.
It does not flow down d and reach the storage tunnel 2,
Since there is no fear of accidents such as corrosion of the container (canister) of the solidified substance package 4 by water, its integrity can be ensured over a long period of time.

Next, a storage facility B according to another embodiment of the present invention will be described with reference to FIG. 2. This storage facility B
Components similar to those of the storage facility A described above are designated by the same reference numerals as in FIG. 1, and detailed explanation thereof will be omitted. In this storage facility B, the lower end of the vertical portion 5b of the shaft 5 is connected to the upper shaft 2 of the storage shaft 2.
The side portion 5c and the connecting portion 5d are approximately horizontal. In addition, drainage tunnel 8
is connected to a main drainage tunnel 9 extending toward the ground surface at a position approximately midway between the lower tunnel 2a and the upper tunnel 2b. This main drainage tunnel 9 is
It also functions to collect and discharge groundwater in the rock around the storage tunnel 2.

Based on this configuration, in the storage facility B, the air in the tunnel is ventilated by the ventilation force generated by the shaft 5, especially the vertical portion 5b, and the solidified material package 4 is cooled, just like the storage facility A described above. With,
Even if rainwater should enter the shaft 5, it can be discharged without flowing into the storage shaft 2. (The solid arrows in FIG. 2 indicate the direction in which air flows, and the dashed arrows indicate the direction in which infiltrated water flows.) The embodiments of this invention have been described above.
The present invention is not limited to the embodiments described above, and various modifications can be made to the shapes of the storage tunnel and the vertical shaft. Further, if necessary, means for promoting the circulation of air in the shaft, such as heating the air in the shaft using a heat pipe to increase the natural ventilation force, may be added. Note that the exhaust tower may be omitted.

〔Effect of the invention〕

As explained in detail above, according to the present invention, since the storage tunnel and the shaft are provided and air is allowed to circulate inside the shaft, the air inside the shaft is ventilated by the natural draft generated by the shaft. , which has the effect of cooling radioactive waste without requiring any power. In addition, since the drainage tunnel is connected to the lower end of the vertical part of the shaft, rainwater will not infiltrate into the storage shaft through the shaft. Therefore, there is no fear that the radioactive waste will come into contact with water and its integrity will be impaired, and its integrity can be ensured over a long period of time.

[Brief explanation of the drawing]

FIG. 1 and FIG. 2 are diagrams showing an embodiment of the present invention. FIG. 1 is a perspective view showing the overall schematic structure of storage facility A of this embodiment, and FIG. 2 is a perspective view showing the overall schematic structure of storage facility B of another embodiment. A, B...In-bedrock storage facility, 1...Bedrock, 2...
...Storage tunnel, 4...Solidified material package (radioactive waste), 5...Shaft shaft, 5a...Open end, 5b...
...Vertical part, 5c...Side part, 5d...Connection part, 8...
...Drainage tunnel, 9...Main drainage tunnel (drainage tunnel).

Claims (1)

[Claims] 1. A shaft extending vertically and open to the atmosphere at the upper end is installed in the underground bedrock, and a storage shaft is connected at one end to the lower end of the shaft and the other end is open to the atmosphere. , air is allowed to circulate inside the shaft and the storage shaft, and radioactive waste is stored in the storage shaft, and the shaft is formed almost vertically and leads to the open end at the upper end of the shaft. the vertical part of the shaft, a side part extending laterally from the side surface of the lower end of the vertical part, and a connecting part communicating the side part with the storage shaft, and the vertical part of the shaft. An in-rock storage facility for radioactive waste with a drainage tunnel connected to the bottom end to drain water from the vertical section.