JP6296309B2 - Filling method of water-swellable clay material - Google Patents

Description

The present invention relates to a method for filling a water-swellable clay material, and more particularly to a method for filling a water-swellable clay material used in a disposal facility for high-level radioactive waste.

  FIG. 13 shows an example of a horizontal waste radioactive waste disposal facility 10.

  In recent years, for example, as shown in FIG. 13, a main mine shaft 11 and a disposal mine shaft 12 are disposed as a horizontal installation type high-level radioactive waste disposal facility 10, and the waste body 13 is embedded in the disposal mine channel 12. Is considered.

The following procedures are considered for the operation procedures of the geological disposal facility.
(1) The “buffer material integrated waste” is carried from the ground to the main underground tunnel through the inclined shaft.
(2) “Buffer material integrated waste” is carried from the main tunnel into the disposal tunnel.
(3) Place a plurality of “buffer material-integrated waste bodies” in order from the back in the disposal tunnel.
(4) When the placement in one disposal tunnel is completed, the gap between the “buffer material integrated waste” and the inner wall of the tunnel is backfilled, and the entrance of the disposal tunnel is closed.
(5) After placing the wastes in all the disposal tunnels and closing the disposal tunnels, after confirming the safety of disposal, bury the entire underground facility and close it.

  FIG. 14 shows a cross-sectional view in a direction perpendicular to the longitudinal direction of the disposal mine shaft 12. FIG. 15 shows a longitudinal sectional view of the disposal mine shaft 12.

  FIG. 14 (a) shows a case where the waste body 13 is placed directly on the disposal tunnel 12, and FIG. 14 (b) shows a case where the waste body 13 is placed on the disposal tunnel 12 via the mounting base 16. FIG. 14 (c) shows a case where the waste body 13 is placed in the disposal tunnel 12 via the divided placement base 16.

  The method of manufacturing the waste 13 on the ground, transporting it into the disposal tunnel 12, and placing it there is no need for detailed work in the main tunnel 11 and the disposal tunnel 12, so that it can be easily operated remotely and the surface dose is reduced. There is an advantage that there is little concern about the exposure of workers because there are few troubles that expose waste in high state.

  However, since the cushioning material integrated waste body 13 is used for transporting heavy objects, a transportation method in consideration of being positioned smoothly and placed in the disposal tunnel 12 is required. In order to be transported into the disposal tunnel 12 and placed at the correct position, a section of the disposal tunnel 12 having a sufficient clearance with respect to the size of the cushioning material integrated waste body 13 is required. As a result, as shown in FIG. 14, the generation of a gap space 14 (hereinafter, this gap space is referred to as a “groove inner circumferential gap”) between the cushioning material integrated waste body 13 and the inner wall of the disposal tunnel 12 is avoided. I can't.

The inner circumferential clearance 14 needs to be filled and sealed in a short time as much as possible with a water-impervious material (for example, a water-absorbing bentonite clay material having a water-absorbing property).
-Since there is a gap 14 inside the tunnel after being placed in the disposal tunnel 12, the rolling movement of the cylindrical cushioning material integrated waste body 13 cannot be suppressed.
-If there is a space in the inner circumferential clearance 14 of the tunnel, when the support work is deteriorated or the ground mountain starts to be deformed, bias pressure acts to impair the soundness of the waste body 13.
-Since the inner perimeter clearance 14 tends to be a passage for groundwater, if radioactive material leaks from the waste body 13 in the future, it tends to be a path that easily moves out of the facility.

  As a method for solving such a problem, there is a method in which a substantially spherical pellet made of bentonite-based material is filled in the inner circumferential clearance 14 of the tunnel. Pellets have a feature that they are easier to drop and fill because they are closer to the dry state and have less frictional force and adhesive force and are fluid. Further, as shown in FIGS. 14 and 15, by providing the stationary base 16 on the bottom surface of the disposal mine shaft 12 at the center of the bottom or at the left and right of the bottom, it becomes easy to fill the water-insulating material in the inner rim of the mine shaft. There is an advantage that it is easy to ensure the quality of the water shielding material of the gap.

  Further, the site where the disposal tunnel 12 is connected to the main tunnel 11 may need to be backfilled with a material 15 having a water-impervious property as shown in FIG. A method of filling and sealing with clay is applied. As a method for filling these spaces with water-swellable clay to form a water-impervious structure, there is a method of filling spherical pellets made by forming bentonite.

  However, when only spherical pellets with a large diameter are filled, there is a possibility that the spherical pellets with a large diameter cannot enter the narrow gap below when the disposal tunnel 12 has a cross section as shown in FIG. . Further, when only spherical pellets having a large diameter are filled, there is a possibility that a gap is generated around the contact portion between adjacent spherical pellets, and the filling density is reduced.

  In addition, if only spherical pellets with a small diameter are filled, a large amount of spherical pellets is required, which increases the cost and the construction time.

  Then, the filling method which mixes and uses the spherical pellet with a large diameter and the spherical pellet with a small diameter is disclosed (refer nonpatent literature 1).

Tomonori Toguri, Hitoshi Kageyama, Eiichi Asano et al. “Study on filling method of bentonite pellets into the gap around cushioning material in horizontal placement method”, Summary of 63rd Annual Conference of Japan Society of Civil Engineers CS05-12, pp. 191-192, September 2008

For example, as in Non-Patent Document 1, when a pellet material in which a 20 mm diameter large particle size pellet and a 1 mm diameter small particle size pellet are mixed in advance at a ratio of 6: 4 is blown into the mold, the filling is performed. The density varied in the range of 0.73 to 1.62 Mg / m ³ .

There was a possibility that the space with a clearance of 50 mm or more in the inner gallery could be made to have a target filling density of 1.37 Mg / m ³ (dry density) or more, but it could be filled to a filling density with little variation. More desirable. Further, in order to ensure water shielding and disposal safety, there is a demand for a method for quality control that pellets are actually filled to a density higher than the target value.

An object of the present invention is to solve the above problems and to provide a method for filling a water-swellable clay material that can be filled to a packing density with little variation.

The filling method of the water-swellable clay material according to the present invention,
A method for filling a water-swelling clay material, in which pellets formed from a material mainly composed of clay having water-swelling properties are formed into a substantially spherical shape, are filled into gaps or partitioned spaces,
After the large particle size pellets are previously rolled up in layers, by dropping the small particle size pellets, the small particle size pellets spill and fill the gaps in the large particle size pellets ,
The layer thickness of the large particle size pellets when the small particle size pellets are rolled out is within 25 times the large particle size pellet particle size,
After rolling out the large particle size pellets, the small particle size pellets are rolled out,
Thereafter, the small particle size pellets are blown off and leveled by jetting high-pressure compressed air, and the small particle size pellets are spilled into the gaps between the large particle size pellets .

Moreover, the filling method of the water-swellable clay material according to the present invention,
After the large particle size pellets are rolled up in layers, the high particle size pellets are blown off by jetting high pressure compressed air, and are equalized .

  Further, in the filling method of the water-swellable clay material according to the present invention, when the large particle size pellets are rolled out, the large particle size pellets are spilled out so as to have a sloped surface, and then the small particle size pellets. When the pellets are dropped and sprinkled, the small particle size pellets spill into the gaps of the large particle size pellets in the surface layer portion to fill the gaps of the large particle size pellets.

  The filling method of the water-swellable clay material according to the present invention is such that the head of the large particle size pellets spun out in layers is not hidden and buried by the small particle size pellets filled later. The small particle size pellets are filled in the gaps of the large particle size pellets.

  Moreover, the filling method of the water-swellable clay material according to the present invention is characterized by injecting high-pressure compressed air from the nozzle while observing the filling state with an observation unit attached to the tip of the nozzle.

  A method for filling a water-swellable clay material according to the present invention is a method for filling a water-swellable clay material, in which a pellet formed by spherically forming a material mainly composed of water-swellable clay is filled into a gap or a partitioned space. Then, after the large particle size pellets are first rolled up into a layer, the small particle size pellets are dropped and rolled out to fill the gaps between the large particle size pellets. Therefore, it is possible to fill the filling density with little variation.

  Furthermore, by observing the accumulation surface of the expansive clay material, it can be confirmed that the small particle size pellets are smoothly filled in the gaps between the large particle size pellets, so that sufficient filling is possible in the filling operation of the inner periphery clearance of the tunnel. It becomes possible to secure the density.

The experimental condition which compared the filling method of the spherical pellet of 1st Embodiment is shown. The experimental situation of the filling method of the spherical pellet of 2nd Embodiment whose layer thickness when the large particle size pellet 1 is rolled out is 1 time the particle size of the large particle size pellet 1 is shown. The experimental situation of the filling method of the spherical pellet of 2nd Embodiment which is 25 times the particle size of the large particle size pellet 1 when the large particle size pellet 1 is rolled out is shown. 3rd Embodiment which fills a spherical pellet in the shape of a slope in a long extension disposal tunnel is shown. The simulation experimental situation of the filling method of the spherical pellet of 3rd Embodiment which fills a spherical pellet in the shape of a slope is shown. The flow of the filling method of the spherical pellet of 3rd Embodiment is shown. The size of the gap of the large particle size pellet on a two-dimensional plane is shown. Each state when the filling height of the small particle size pellets in the gaps of the large particle size pellets is changed is shown. The filling method of the spherical pellet of 5th Embodiment which blows off a small particle size pellet using an injection apparatus is shown. The flow of the filling method of the spherical pellet of 6th Embodiment is shown. The pellet filling apparatus 50 at the time of applying in the radioactive waste disposal facility 10 of a horizontal installation type is shown. The side view which permeate | transmitted the disposal tunnel 12 of FIG. 11 is shown. An example of the horizontal waste type radioactive waste disposal facility 10 is shown. Sectional drawing of the direction orthogonal to the longitudinal direction of the disposal mine shaft 12 is shown. A sectional view in the longitudinal direction of the disposal mine shaft 12 is shown.

  Hereinafter, embodiments of a method for filling spherical pellets according to the present invention will be described with reference to the drawings.

  FIG. 1 shows an experimental situation in which the spherical pellet filling methods of the first embodiment are compared.

  The method for filling spherical pellets of the first embodiment is a case of filling pellets 1 and 2 formed into a substantially spherical shape with a material mainly composed of clay having water-absorbing expansibility into gaps or partitioned spaces. After the particle size pellets 1 have been rolled up in advance, the small particle size pellets 2 having a particle size smaller than the particle size of the large particle size pellets 1 are dropped, so that the small particle size pellets 2 are spilled and large. The gap between the particle size pellets 1 is filled. Here, the substantially spherical shape does not necessarily need to be a perfect sphere, and may be any shape as long as it can roll on a substantially spherical and inclined plane.

  For example, in a transparent cylindrical container 3 (inner dimensions: diameter 100 mm, height 127 mm), a large particle size pellet 1 having an average particle size of about 19 mm with a particle size range of 16.0 mm or more and less than 22.4 mm is arranged as dense as possible. Let the container fill completely. Thereafter, the following three types of small particle size pellets 2 having different particle size ranges were rolled out, and the state in which the small particle size pellets 2 spilled and filled in the gaps of the large particle size pellets 1 was observed.

In the case of the first small particle size pellet 21 having an average particle size of about 1 mm, the first small particle size pellet 21 smoothly flows down into the gap between the large particle size pellets 1 as shown in FIG. Since the gap between the large particle size pellets 1 to the bottom of 127 mm could be filled with the first small particle size pellets 21, the packing density was 1.4894 Mg / m ³ .

In the case of the second small particle size pellet 22 having an average particle size of about 2 mm, the second small particle size pellet 22 spills up to the gap of the large particle size pellet 1 up to a depth of about 40 mm as shown in FIG. However, the filling density was 1.2711 Mg / m ³ because it could not be filled to a depth greater than that.

In the case of the third small particle size pellet 23 having an average particle size of about 4 mm, the third small particle size is placed in the gap between the large particle size pellets 1 at a depth deeper than about 20 mm as shown in FIG. Since the pellets 23 were not filled, the packing density was 1.1388 Mg / m ³ .

As shown in FIG. 1D, when only the large particle size pellet 1 is filled, the filling density is 0.9898 Mg / m ³ .

  Table 1 below shows the results of measuring the packing density.

  In this way, it is effective to fill large and small two particle size pellets having significantly different particle sizes. From this result, it can be estimated that it is particularly suitable that the maximum particle size of the small particle size pellet 2 is 1/19 or less compared to the minimum particle size of the large particle size pellet 1.

  Here, a reference example of Non-Patent Document 1 that is not included in the present embodiment will be described.

  First, the case where large and small 2 particle size pellets are mixed and dropped and filled will be described.

  For example, large particle size pellets (particle size of about 20 mm class) and small particle size pellets (particle size of about 1 mm class) are premixed in advance and then transported through a transport tube and positioned near the top of the target space. When continuously dropping and filling from the outlet of the transport pipe, the value of the filling density varies depending on the filling location.

The reason is considered as follows.
(1) Since a very small gap portion having a width of 30 mm or less cannot be almost filled with a large particle size pellet, only a small particle size pellet was filled.
(2) In the course of transporting through the transport tube after pre-mixing, the large particle size pellets and the small particle size pellets were separated and dropped from the transport tube outlet at an uneven mixing ratio.
(3) The large and small 2 particle size mixed pellets that have fallen from the outlet of the transport pipe fall while rolling along the mold surface in the mold space, and the large particle size pellet and the small particle size pellet are separated on the way, Furthermore, it was deposited in the space with an uneven mixing ratio.
(4) Since the small particle size pellets are dropped and filled together, there are many cases where the small particle size pellets exist between the large particle size pellets and the large particle size pellets are adjacent to each other. It was difficult to fill in the state of being arranged.

  For this reason, the small gap is filled with only small particle size pellets and there is almost no large particle size pellet, and the top end is filled with only large particle size pellets and small particle size. The area was almost free of pellets. That is, it is considered that the premixed pellets are caused by the fact that the mixing ratio of the large particle size pellets and the small particle size pellets cannot be changed flexibly. That led to the variation in packing density.

  In addition, there is known an example in which vibration energy is added when a space is filled with a particulate substance. Therefore, a case where vibration energy is given after filling pellets having large and small particle sizes will be described.

For example, a transparent cylindrical container (inner diameter: 162 mm, height: 232 mm) is filled with large particle size pellets and small particle size pellets, and the packing density is 1.487 Mg / m ³ (in terms of dry density, all the densities below are converted into dry density) Value).), And a change in packing density was observed by applying excitation energy. As a result, the packing density of the large particle size pellet and the small particle size pellet in the cylindrical container was reduced by the vibration.

  This is because the small particle size pellet moves under the large particle size pellet at the moment when the large particle size pellet moves up and down due to vibration, and the small particle size pellet is gradually biased toward the bottom. As a result, large particle size pellets remained in the upper layer portion, and the overall bulk (deposition) gradually increased.

  As described above, when filling the gap or partitioned space with pellets formed of a material mainly composed of clay having water-absorbing expansibility into a gap or partitioned space, the large particle size pellet 1 is preceded as in the present embodiment. In comparison with the method of dropping the small particle size pellet 2 having a particle size smaller than the particle size of the large particle size pellet 1, the large and small size 2 particle size pellets are mixed and dropped and filled in advance. It has been found that the method and the method of applying vibrational energy are not suitable.

  That is, when pellets 1 and 2, which are formed in a substantially spherical shape from a material mainly composed of clay having water-absorbing expansibility, are filled in gaps or partitioned spaces, the large particle size pellets 1 are layered in advance. After the rolling, the small particle size pellet 2 is dropped and rolled out, so that the small particle size pellet 2 spills down and fills the gaps of the large particle size pellet 1, thereby reducing the filling unevenness of the small particle size pellet 2. In other words, it is possible to fill with a filling density with little variation.

  However, if the layer thickness of the large particle size pellet 1 is too large, the small particle size pellet 2 is difficult to drop to the bottom, and as a result, the filling density of the entire container 3 does not increase. Therefore, the difference in the filling state of the small particle size pellet 2 is examined by changing the rolling thickness of the large particle size pellet 1.

FIG. 2 shows the experimental situation of the filling method of spherical pellets of the second embodiment in which the layer thickness of the large particle size pellet 1 when the small particle size pellet 2 is rolled out is one time the particle size of the large particle size pellet 1 Indicates. FIG. 3 shows the experimental situation of the spherical pellet filling method of the second embodiment in which the layer thickness of the large particle size pellet 1 when the small particle size pellet 2 is rolled out is 25 times the particle size of the large particle size pellet 1. Indicates.

  For example, Table 2 shows the results of conducting a filling experiment on a transparent cylindrical container 3 (inner dimensions: diameter 100 mm, height 127 mm to 508 mm) and observing the difference in filling density.

As shown in Table 2, the largest filling method is the method of repeating the method of filling the gap between the large particle size pellets 1 after the large particle size pellets 1 are layered and the particle size is 1 times the particle size. The density was 1.5199 Mg / m ³ . Even if the layer thickness of the large particle size pellet 1 was increased to 3 times the particle size, the packing density was 99% or more compared to the former packing density. Furthermore, even when the layer thickness is 127 mm to 508 mm, which is 6 to 25 times the particle size, the small particle size pellet 2 flows down and fills the gaps of the large particle size pellet 1, and the overall packing density is 97%. That's it.

Therefore, when the small particle size pellet 2 is rolled out, the layer thickness of the large particle size pellet 1 is within 25 times the particle size of the large particle size pellet 1 so that the small particle size pellet 2 becomes the large particle size pellet. Since one gap can be uniformly dropped and filled, it is possible to maintain a filling density with little variation.

  In the present invention, several types of experimental results under different conditions are shown as packing density values, which are expressed as dry density values. Also for the experimental results shown below, since the packing density value as a comparison source differs depending on each experimental condition, the effect of the invention was evaluated by relative comparison. This is because the packing density value has poor reproducibility, and thus a relative comparison under the experimental conditions is appropriate.

  Next, the case of the third embodiment in which the clearance inside the tunnel between the buffer material integrated waste body and the inner wall of the tunnel is filled with the water-absorbing expansive pellets in the disposal tunnel with a long extension will be described.

  FIG. 4 shows a third embodiment in which spherical pellets are filled in a long extension disposal tunnel. FIG. 5 shows a simulation experiment situation of the spherical pellet filling method of the third embodiment in which spherical pellets are filled in a slope shape. FIG. 6 shows a flow of the spherical pellet filling method of the third embodiment.

  As shown in FIG. 4, when the spherical pellets 1, 2 are dropped and filled in a disposal tunnel with a long extension, it is expected to be backfilled in a slope shape. Therefore, it must be ensured that even if it is filled with such an angle of repose, it can be filled to a predetermined density or more.

  Therefore, in the third embodiment, when the large particle size pellet 1 is rolled out, it is spilled out so that the rolling surface has a slope shape, and then the small particle size pellet 2 is dropped and rolled out. The small particle size pellets 2 spill into the gaps between the large particle size pellets 1 in the surface layer and fill the gaps in the large particle size pellets 1.

  When the waste 13 of radioactive waste is placed in the disposal mine shaft 12 and then the gap in the mine shaft is backfilled, the spherical pellets 1 and 2 are filled from the top of the mine tunnel. 1 and 2 are dropped and spread. At this time, since the spherical pellets 1 and 2 are naturally spilled along the slope shape, the spherical pellets 1 and 2 have a slope-like spread leveling surface as shown in FIG. In such a filling method, it is effective to combine the methods shown in the first embodiment and the second embodiment.

  A transparent mold having a rectangular cross section shown in FIG. 5 (width 350 mm, height 255 mm, depth 100 mm, volume 8925 mL, filling simulation experiment was attempted according to the flow shown in FIG. 6.

  First, in Step 1, the large particle size pellet 1 is dropped from the deepest top end of the container 32 to start dropping (ST1).

  Next, in step 2, the large particle size pellet 1 is deposited in a slope shape, and the layer thickness of the large particle size pellet 1 is sprinkled until it becomes about three times the particle size of the large particle size pellet 1 (ST2).

  Subsequently, in step 3, as shown in FIG. 5 (a), the large particle size pellets 1 are deposited in layers to form slopes with irregularities (ST3).

  Next, in Step 4, the small particle size pellet 2 is dropped from the top end of the container 32 at the upper part of the slope (ST4).

  Subsequently, in step 5, as shown in FIG. 5 (b), the small particles are filled when the small particle size pellet 2 fills the gap of the large particle size pellet 1 while the small particle size pellet 2 flows down the slope formed by the large particle size pellet 1. The diameter pellet 2 is rolled out so as not to overflow on the slope (ST5).

  Next, in step 6, it is determined whether or not the filling to the top end of the container 32 is completed (ST6).

  In step 6, when the filling to the top end of the container 32 is not completed, the process returns to step 3, and the operations of steps 3 to 5 are repeated as shown in FIG.

  In step 6, as shown in FIG.5 (d), when filling to the top end of the container 32 is completed, work is complete | finished.

By filling the large particle size pellets 1 and the small particle size pellets 2 in this way, the small particle size pellets 2 spilled later are spilled and filled in the gaps between the large particle size pellets 1 having a slope shape. I was able to confirm that. The packing density of the filling method of the spherical pellets 1 and 2 of the third embodiment is 1.4893Mg / m ^3, was filled in 1.37 Mg / m ³ or more packing density which has been targeted.

Here, as in the case of the third embodiment, the large particle size pellets 1 are horizontally rolled up one layer at a time, and then the small particle size pellets 2 are filled for one layer of the large particle size pellets 1. The packing density is compared with the case where the filling method is repeated. As shown in Table 3 below, the packing density when the small particle size pellets 2 were filled after the large particle size pellets 1 were horizontally rolled up was 1.5369 Mg / m ³ . The filling density by the filling method in which it is rolled like a slope and naturally flows down on the slope as in the third embodiment is 1.4893 Mg / m ³ , and after the large particle size pellets 1 are rolled up one layer at a time. Compared with 1.5369 Mg / m ³ in the case of filling the small particle size pellet 2, the filling corresponding to 96.9% is possible.

  In this way, when the large particle size pellet 1 is rolled out, it is spilled and dropped so that the rolling surface becomes an inclined surface, and then the small particle size pellet 2 is dropped and rolled out, thereby reducing the small particle size. Since the pellet 2 spills and fills the gap of the large particle size pellet 1 in the surface layer portion, when filling the narrow tunnel inner circumferential clearance space 14 extending in the extension direction in the tunnel, filling with little variation It is possible to achieve density.

  Next, the small particle size pellets 2 are placed in the gaps of the large particle size pellets 1 so that the heads of the large particle size pellets 1 that have been rolled up are not hidden and buried by the small particle size pellets 2 that are filled thereafter. The case of the fourth embodiment to be filled will be described.

  FIG. 7 shows the size of the gap of the large particle size pellet 1 on a two-dimensional plane. FIG. 8 shows each state when the filling height of the small particle size pellet 2 in the gap of the large particle size pellet 1 is changed.

  Since the prospect that a larger packing density can be realized by dropping the large and small 2 particle size mixed pellets 1 and 2 separately into layers, the small particle size pellet 2 is replaced with the large particle size pellet 1 as follows. An experiment was conducted to determine how far the gap is suitable.

  FIG. 7 is a diagram exemplifying the size of the pellet gap on a two-dimensional plane assuming that the large particle size pellet 1 has an equal particle size. Since 1 is adjacent three-dimensionally, the gap shape is different from the figure, and when viewed from above, there is a gap in which the small particle size pellet 2 can fall in the gap between the large particle size pellets 1. Can be estimated.

  In 2D geometry. As illustrated in FIG. 7, it is presumed that it is a desirable condition that the large particle size pellet 1 has a diameter of 0.268 times or more (0.536 times or more of the radius r) protruding from the small particle size pellet. . Actually, the conditions differ because the large-diameter pellets 1 are three-dimensionally adjacent to each other. Therefore, using a cylindrical container (not shown) having an inner diameter of 100 mm and a height of 127 mm, the small-diameter particle in the gap of the large-diameter pellet 1 A filling experiment was conducted in which the filling height of the pellets 2, in other words, the cueing height of the large particle size pellets 1 after the small particle size pellets 2 were sprinkled, and the filling density at that time was observed. Table 4 below.

As shown in Table 4, the small particle size pellet 2 is filled so that the head of the large particle size pellet 1 is exposed from the small particle size pellet 2 about 1.5 times the diameter as shown in FIG. In the case of about 5/6 as shown in FIG. 8 (b), and about 1/6 as shown in FIG. 8 (c), the small particle size pellet 2 is exposed from the small particle size pellet 2. When filled, the total packing density is almost the same in the range of 1.5235 to 1.5335 Mg / m ³ , and the head of the large particle size pellet 1 is exposed from the small particle size pellet 2 by about 5/6. Compared with the relative value of 1.5335 Mg / m ³ as a total value of 1.5335 Mg / m ³ when the small particle size pellet 1 is filled, the packing density is 99% or more.

On the other hand, as shown in FIG. 8 (d), the small particle size is in a state where the head of the large particle size pellet 1 is almost buried, in other words, until the small particle size pellet 2 is filled so as to be exposed about 0 times the diameter. When the pellet 2 is rolled out and filled, the packing density is close to 96%, 1.4688 Mg / m ³ .

In addition, as shown in FIG. 8 (e), when the small particle size pellet 2 is unrolled and filled to the state where the head of the large particle size pellet 1 is completely hidden and buried about 1/2 times the diameter, The total packing density is about 94% at 1.4360 Mg / m ³ .

Therefore, by filling so that at least the large particle size pellets 1 are not hidden behind the small particle size pellets 2 that are spun out thereafter, a large filling with a margin compared to the target 1.37 Mg / m ³ It has been found that density can be achieved.

  In this way, the small particle size pellets 2 are separated from the large particle size pellets 1 so that the heads of the large particle size pellets 1 rolled up in layers are not hidden and buried by the small particle size pellets 2 filled thereafter. When it is filled, it is possible to achieve a packing density with a higher packing density and less variation.

  Next, after the large particle size pellets 1 are rolled up in layers, the small particle size pellets 2 are rolled out, and then the small particle size pellets 2 are blown off using a high-pressure compressed air injection device, and the large particle size pellets 2 are leveled. The case of the fifth embodiment in which the small particle size pellet 2 is spilled and dropped into the gap between the particle size pellets 1 will be described. In the spherical pellet filling method of the fifth embodiment, the small particle size pellet 2 may be blown off while observing the filling state using a high-pressure compressed air injection device having an observation device at the tip.

  FIG. 9 shows a spherical pellet filling method of the fifth embodiment in which the small particle size pellets 2 are blown off by using an injection device.

  FIG. 9A illustrates a method in which high-pressure compressed air is ejected from the nozzle 4 so that the small particle size pellet 2 is blown off and dropped into the gaps of another large particle size pellet 1. The method for moving the small particle size pellets 2 is not limited to the method of blowing off by the jet of compressed air, but may be the method of blowing out using a brush having a suitable flexibility. It was confirmed that the law has feasibility.

  As a means for dropping and filling the small particle size pellets 2 into the gaps of the large particle size pellets 1, as implemented in the experiment of FIG. 5, there is a method of simply dropping from above and spilling down on the slope. Actually, it is difficult for humans to directly see the pellets in the space shown in Fig. 4, so it is not realistic to finely adjust the drop position and drop filling amount to control the packing density. Absent.

  In order to solve this problem, a remote observation device 5 is necessary as shown in FIG. For example, the remote observation unit 5 can observe by moving a free arm with a small video camera attached to the tip, and can also observe using a fiberscope similar to a stomach camera. In this case, it is not sufficient to observe only, and as shown in FIG. 9 (b), the small particle size pellet 2 that has been excessively sprinkled on the large particle size pellet 1 as shown in FIG. 9 (a). It is necessary to move to the unfilled gaps of the surrounding large particle size pellets 1.

  Here, the same transparent cylindrical container as shown in FIG. 1 is used in such a manner that high-pressure compressed air is ejected from the nozzle 4 and the small particle size pellets 2 are blown away to be spilled and filled into the gaps of the large particle size pellets 1. An attempt was made to fill (with an inner diameter of 100 mm and a height of 127 mm). Table 5 below compares the measurement results of the filling density when the filling is performed by the method using the injection device and the method not using the injection device.

  When air leveling is performed, the packing density is slightly larger than the value of the total packing density when air leveling is not performed. This is probably because the small particle size pellets were better filled in the gaps of the large particle size pellets by blowing off by air injection. That is, the air leveling method is excellent as a stable and dense filling method.

  In this way, the small particle size pellet 2 is rolled out, and then the small particle size pellet 2 is blown out using the high-pressure compressed air injection device, and the small particle size pellet 2 is inserted into the gap between the large particle size pellets 1. Therefore, it is possible to achieve a packing density with higher packing density and less variation.

  Further, using the observation unit 5 attached to the tip of the nozzle 4 of the high-pressure compressed air injection device, the small particle size pellet 2 is blown off and leveled while observing the filling state, and the large particle size pellet 1 is inserted into the gap. Since the small particle size pellet 2 is spilled off, it can be filled while checking the situation, and a sufficient filling density can be ensured.

  Next, the small particle size pellet 2 dropped and sprinkled on the large particle size pellet 1 having a slope shape is spread along the inclined surface by the compressed air ejection method, and the small particle size pellet 2 is made large particle size. The case of the sixth embodiment that fills the gap between the pellets 1 will be described.

  In the sixth embodiment, even after the large particle size pellets 1 are rolled out in layers, the large particle size pellets 1 can be formed without any gaps by blowing off the large particle size pellets 1 using a high-pressure compressed air injection device. Apply the example of leveling in line.

  FIG. 10 shows a flow of the spherical pellet filling method of the sixth embodiment.

  In a transparent mold (width 350 mm, height 255 mm, depth 100 mm, volume 8925 mL) having the same rectangular cross section as shown in FIG. 5, a filling simulation experiment was performed according to the procedure shown in FIG. 10.

  First, in step 11, the large particle size pellet 1 is dropped from the innermost end of the container and starts dropping (ST11).

  Next, in step 12, the large particle size pellet 1 is deposited in a slope shape, and the layer thickness of the large particle size pellet 1 is sprinkled until it becomes about three times the particle size of the large particle size pellet 1 (ST12).

  Subsequently, in step 13, the large particle size pellets 1 are deposited in layers to form slopes with unevenness (ST13).

  Subsequently, in step 14, in the large particle size pellets 1 deposited in a layered manner on the slope, the large particle size pellets locally forming the convex portion are moved to the concave portion of the slope by jetting compressed air, The unevenness of the slope is smoothed (ST14).

  Next, in step 15, the small particle size pellet 2 is dropped from the top end of the container on the upper slope (ST15).

  Subsequently, in step 16, the small particle size pellet 2 does not overflow on the slope when filling the gap of the large particle size pellet 1 while the small particle size pellet 2 flows down on the slope formed by the large particle size pellet 1. Nimakiso (ST16)

  Subsequently, in step 17, the small particle size pellets 2 are blown off by compressed air and leveled on the slope, and the large particle size pellets 1 from the filled small particle size pellets 2 are 1 to 1/2 the particle size. The state is exposed to about twice (ST17).

  Next, in step 18, it is determined whether or not filling to the top of the container is completed (ST18).

  In step 18, when the filling to the top of the container is not completed, the process returns to step 13 and the operations in steps 13 to 17 are repeated.

  In step 18, when the filling to the top of the container is completed, the operation is finished.

  Table 6 below shows the total packing density when the container is rolled up horizontally and visually filled, the packing density when it is simply spilled and filled on the slope, and the case where the slope is filled by air leveling These are comparisons of the packing density.

As shown in Table 6, the packing density when air is leveled and filled on the slope is compared to the total packing density value of 1.5369 Mg / m ³ when it is horizontally spread and visually filled. The packing density is as large as 1.5004 Mg / m ³ , corresponding to 97.6%. In addition, since the packing density is higher than 1.4893 Mg / m ³ when the spill is simply spilled on the slope, it is understood that the air leveling method is excellent.

  Since the small particle size pellets 2 are rolled out, and then the small particle size pellets 2 are blown off using the high-pressure compressed air jet device, and the small particle size pellets 2 are spilled into the gaps between the large particle size pellets 1 Thus, it is possible to achieve a packing density with a higher packing density and less variation.

  Further, using the observation unit 5 attached to the tip of the nozzle 4 of the high-pressure compressed air injection device, the small particle size pellet 2 is blown off and leveled while observing the filling state, and the large particle size pellet 1 is inserted into the gap. Since the small particle size pellet 2 is spilled off, it can be filled while checking the situation, and a sufficient filling density can be ensured.

  In addition, even after the large particle size pellets 1 have been laid out in layers, the large particle size pellets 1 are leveled so that the large particle size pellets 1 are arranged without gaps by blowing off the large particle size pellets 1 using a high-pressure compressed air injection device. Further, it is possible to achieve a packing density with a higher packing density and with less variation.

  Next, a pellet filling apparatus when the spherical pellet filling method of the sixth embodiment is applied in the horizontal radioactive waste disposal facility 10 shown in FIG. 100 will be described.

  FIG. 11 shows a pellet filling apparatus 50 when applied in a horizontal radioactive waste disposal facility 10. FIG. 12 shows a side view through the disposal tunnel 12 of FIG.

  A pellet filling device 50 having a shape and dimension capable of moving in a narrow space between the buffer material integrated waste body and the inner wall of the disposal tunnel 12 is provided. The pellet filling device 50 includes a main body 51 and a main body 51 from the entrance of the disposal tunnel 12. A transport pipe 52 for transporting the pellets 1 and 2 connected to the transport pipe, a transport section (not shown) for transporting the pellets 1 and 2 to be filled through the transport pipe 52 from the main body 51 to the filling position, and a pellet 1 having a large and small particle size. , 2 can be dropped separately, a nozzle 4 that sprays compressed air onto the surfaces of the pellets 1 and 2 that have been filled and deposited, and blows off the pellets 1 and 2, and supplies compressed air to the nozzle 4 By operating a joint by remote operation, a compressed air supply unit (not shown), an observation unit 5 that can observe the pellet deposition surface in the direction of jetting compressed air from the nozzle 4 near the tip of the nozzle 4 Has a free arm 54 can be moved along the surface of the pellets 1 and 2 is deposited a tip and observation portion 5 of the nozzle 4, the.

  As shown in FIG. 11, since the tunnel inner circumferential clearance 14 between the waste body 13 and the inner wall of the disposal tunnel 12 is narrow, it is difficult for an operator to fill the pellets 1 and 2 while directly observing. . Therefore, it is desirable to use a pellet filling apparatus 50 capable of filling the pellets 1 and 2 by remote operation.

Such a pellet filling apparatus 50 needs at least the following five functions.
(1) The function of conveying pellets 1 and 2 to the vicinity of the filling location (2) The function of dropping and filling the large particle size pellet 1 (3) As with the remote observation unit 5, the compressed air guided to the tip is supplied to the tip of the nozzle 4 A function to move the large particle size pellet 1 to level the slope with less irregularities by ejecting from (4) A function to drop the small particle size pellet 2 and to start out (5) The tip as with the remote observation unit 5 The function of filling the gaps between the large particle size pellets 1 while leveling the small particle size pellets 3 by ejecting the compressed air guided to the section from the tip of the nozzle 4

  As shown in FIGS. 11 and 12, the pellet filling device 50 has a main body 51 having a dimension and shape that can move in a narrow mine tunnel clearance 14. Further, the pellets are transferred to the pellet filling device 50 by passing a predetermined amount of pellets 1 and 2 by air or the like through a transport pipe 52 (not shown) from the main tunnel 11 to which the disposal tunnel 12 is connected. 1, 2 can be supplied.

  Therefore, it is possible to efficiently realize a pellet filling density of a predetermined value or more in the inner lane clearance 14 which is a narrow space.

  Moreover, since the observation part 5 is attached to the front-end | tip part of the free arm 54, the upper end surface after rolling out the pellets 1 and 2 can be observed. Similarly, the nozzle 4 is fixed at the tip of the free arm 54 so that the direction of the nozzle 4 can be controlled in a variable manner, and the excess pellets 1 and 2 are moved to another place by injecting compressed air while observing with the observation unit 5. Can be made.

  That is, when the air is blown out from the nozzle 4 and the small particle size pellets 2 are blown off and the particles are spilled and dropped into the gaps of the large particle size pellets 1, the observation unit 5 By observing that the small-diameter pellets 2 are uncovered so that the heads of the small-diameter pellets 1 are not hidden behind and buried by the small-diameter pellets 2 that are filled thereafter, the filling is more than a predetermined packing density. Make sure it is done.

  Therefore, since the filling state of the small particle size pellets 2 in the gaps between the large particle size pellets 1 can be confirmed, it is observed that the pellets 1 and 2 are filled to a predetermined density or more to ensure the packing density. It is possible.

  Thus, in the filling method of the water-swellable clay material of the present embodiment, the water-absorbing water filling the gaps or partitioned spaces with the pellets 1 and 2 formed into a spherical shape from a material mainly composed of water-swellable clay. A method for filling inflatable clay material, in which a large particle size pellet 1 is first rolled up in layers, and then a small particle size pellet 2 is dropped and then rolled out. Since the gap between the particle size pellets 1 is filled, it is possible to fill the packing density with little variation.

Moreover, in the filling method of the water-swellable clay material of this embodiment, the layer thickness of the large particle size pellet 1 when the small particle size pellet 2 is rolled out is within 25 times the particle size of the large particle size pellet 1. As a result, the small particle size pellets 2 can be uniformly dropped and filled in the gaps of the large particle size pellets 1, so that it is possible to maintain a packing density with little variation.

  Moreover, in the filling method of the water-swellable clay material of the present embodiment, when the large particle size pellets 1 are rolled out, the large particle size pellets 1 are spilled out so as to have a sloped surface, and then the small particle size pellets 2 The small particle size pellet 2 spills into the gap between the large particle size pellets 1 in the surface layer and fills the gap between the large particle size pellets 1, so that it extends in the extension direction in the tunnel. When continuously filling the narrow tunnel inner circumferential clearance space 14, it is possible to achieve a filling density with little variation.

  Further, the filling method of the water-swellable clay material of the present embodiment is such that the head of the large particle size pellets 1 sprinkled in layers is not hidden and buried by the small particle size pellets 2 filled later. Since the small particle size pellets 2 are filled in the gaps between the large particle size pellets 1, it is possible to achieve a higher packing density and a smaller packing density.

  Moreover, the filling method of the water-absorbing expandable clay material of the present embodiment is such that after the large particle size pellet 1 is rolled out in a layered form, the small particle size pellet 2 is rolled out, and then high pressure compressed air is jetted. Since the small-diameter pellets 2 are blown off and smoothed, and the small-diameter pellets 2 are spilled and dropped into the gaps between the large-diameter pellets 1, it is possible to achieve a higher packing density and less variation in packing density. Become.

  Moreover, since the filling method of the water-swellable clay material of this embodiment blows off the large particle size pellet 1 by spraying the high particle size pellet 1 after spraying the large particle size pellet 1 into a layer, It is possible to achieve a packing density with a high packing density and less variation.

  Moreover, the filling method of the water-swellable clay material according to the present embodiment injects high-pressure compressed air from the nozzle 4 while observing the filling state with the observation unit 5 attached to the tip of the nozzle 4, so that the state is confirmed. It can be filled, and it becomes possible to ensure a sufficient filling density.

  Moreover, the water-swellable clay material filling device 50 according to the present embodiment is configured such that pellets 1 and 2 formed in a spherical shape from a material mainly composed of water-swellable clay are disposed between the waste body 13 and the inner wall of the disposal tunnel 12. A water-absorbing expansive clay material filling device 50 for filling the narrow space 14, a body 51 having a shape and dimension capable of moving in the narrow space 14 between the waste body 13 and the inner wall of the disposal tunnel 12, A transport pipe 52 that communicates with the main body 51 from the entrance to transport the water-swellable clay material 1 and 2 and a transport unit that transports the water-swellable clay material 1 and 2 to be filled through the transport pipe 52 from the main body to the filling position. And, a water-swelling clay material 1 and 2 having different large and small particle diameters can be dropped separately, and a water-absorbing water is obtained by jetting compressed air onto the surfaces of the water-swelling clay materials 1 and 2 that are filled and deposited. Blow away the expansive clay materials 1 and 2 Observe the deposited surface of the water-absorbing expandable clay materials 1 and 2 attached in the vicinity of the nozzle 4, the compressed air supply part for supplying the compressed air to the nozzle 4, and the vicinity of the tip of the nozzle 4, and injecting the compressed air from the nozzle 4 And a free arm 54 that moves the tip of the nozzle 4 and the observation unit 5 along the surface of the water-swellable clay material 1 and 2 by being operated by remote control. Thus, it is possible to fill the filling density with little variation.

  In addition, this invention is not limited by this embodiment. That is, in describing the embodiment, many specific details are included for illustration, but those skilled in the art may add various variations and changes to these details. Moreover, you may form combining them.

DESCRIPTION OF SYMBOLS 1 ... Large particle size pellet 2 ... Small particle size pellet 3 ... Container 4 ... Nozzle 5 ... Observation part

Claims (5)

A method for filling a water-swelling clay material, in which pellets formed from a material mainly composed of clay having water-swelling properties are formed into a substantially spherical shape, are filled into gaps or partitioned spaces,
After the large particle size pellets are previously rolled up in layers, by dropping the small particle size pellets, the small particle size pellets spill and fill the gaps in the large particle size pellets,
Ri Der thickness of the large grain size pellets within 25 times of the large grain size pellets particle size when unrolled pellets of the small particle size,
After rolling out the large particle size pellets, the small particle size pellets are rolled out,
Thereafter, the small particle size pellets are blown off by jetting high pressure compressed air, and the small particle size pellets are spilled into the gaps between the large particle size pellets. To fill the clay material. After the large grain size pellets unrolled in layers, the method of filling the water-swellable clay material according to claim 1, characterized in that leveling blow off the large grain size pellets by ejecting high pressure compressed air . When rolling out the large particle size pellets, spilled out so that the rolling surface becomes a sloped shape,
Then, by dropping the small particle size pellets,
The filling of the water-absorbing expandable clay material according to claim 1 or 2 , wherein the small particle size pellets fall into a gap between the large particle size pellets in a surface layer portion to fill the gap between the large particle size pellets. Method. The small particle size pellets are filled in the gaps of the large particle size pellets so that the heads of the large particle size pellets sprinkled in layers are not hidden and buried by the small particle size pellets filled later. The method of filling a water-swellable clay material according to any one of claims 1 to 3 . The water-absorbing and expansive clay material according to any one of claims 1 to 4 , wherein high pressure compressed air is jetted from the nozzle while observing a filling state with an observation unit attached to a tip of the nozzle. Filling method.

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