JP7443289B2 - radiation shield - Google Patents

Description

TECHNICAL FIELD The present invention relates to a radiation shield.

It is necessary to provide a gap between two architectural/civil engineering structures (for example, a nuclear power building and a turbine building) in a nuclear power plant in order to prevent the structures from interfering with each other in the event of an earthquake. This gap can be a weak point for radiation shielding.

As a radiation shielding measure for such a gap between two structures, for example, Patent Document 1 discloses a structure that is installed between a high-dose area and a low-dose area of a radiation handling facility to form a stepped gap. A radiation shield consisting of a first and a second shield is disclosed in which the thickness of the first and second shields is set to a thickness that can shield the gap depending on the intensity of the radiation source to be shielded. There is.

Japanese Patent Application Publication No. 5-215894

However, the construction method of the radiation shielding body disclosed in Patent Document 1 is not easy because the shape of the concrete wall is complicated. It is also difficult to add this radiation shield to existing structures within a nuclear power plant.

An object of the present invention is to provide a radiation shield that is easy to construct and can be easily added to an existing structure.

In order to achieve the above object, the present invention provides a radiation shielding sheet that is flexible and spans the gap in a bent state, and fixes the shielding sheet to the two adjacent structures. A fixing device is provided.

According to the present invention, it is easy to construct a radiation shield installed between structures such as two buildings in a nuclear power plant, and it can be easily added to an existing structure in a nuclear power plant. Problems, configurations, and effects other than those described above will be made clear by the following description of the embodiments.

It is a piping diagram of the main steam piping of a nuclear power plant. FIG. 3 is a plan view showing a gap provided between two buildings. FIG. 1 is a perspective view of a radiation shield according to a first embodiment of the present invention. FIG. 2 is a plan view of a shielding sheet of a radiation shielding body according to a first embodiment of the present invention. 1 is a perspective view of a plate-like member and an equation showing the relationship between the thickness and bending rigidity of the plate-like member. FIG. 3 is a perspective view of a radiation shield according to a second embodiment of the present invention. FIG. 7 is a perspective view of a radiation shield according to a third embodiment of the present invention. 8 is a cross-sectional view taken along the line AA of the radiation shield shown in FIG. 7. FIG. 8 is a cross-sectional view taken along the line AA of another embodiment of the radiation shield shown in FIG. 7. FIG. 8 is a cross-sectional view taken along the line AA of another embodiment of the radiation shield shown in FIG. 7. FIG. 8 is a cross-sectional view taken along the line AA of another embodiment of the radiation shield shown in FIG. 7. FIG. 8 is a cross-sectional view taken along the line AA of another embodiment of the radiation shield shown in FIG. 7. FIG. FIG. 7 is a perspective view of a radiation shield according to a fourth embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Radiation shields according to first to fourth embodiments of the present invention will be described below with reference to the drawings. Note that in each figure, the same reference numerals indicate the same parts. In addition, in each of the plan view and cross-sectional view, the directions are specified by the XYZ axes that are perpendicular to each other, and +X is "right", -X is "left", +Y is "top", -Y is "bottom", and +Z is "bottom". Define "front" and -Z as "rear".

(First embodiment)
There are equipment with high radiation doses (hereinafter referred to as high-radiation equipment) inside nuclear power plants. For example, the main steam pipe 110, which is a high radiation dose device, needs to be covered and shielded with, for example, a shielding wall 100, as shown in FIG. The main steam pipe 110 in FIG. 1 is laid across from the inside of the reactor building 120 to the inside of the turbine building 130 in order to circulate steam from the nuclear reactor to the turbine. Therefore, it is preferable that the shielding wall is also provided spanning the reactor building 120 and the turbine building 130. However, a gap 140 (see FIG. 2) is provided between the two buildings 120, 130 in order to accommodate relative displacement caused by shaking of each building 120, 130 due to an earthquake or the like. Therefore, the actual shielding wall 100 cannot be provided across the two buildings, resulting in a gap 140 (see FIG. 1). The radiation shield 10 according to this embodiment is laid so as to cover this gap 140.

FIG. 3 is a perspective view of the radiation shield 10 according to this embodiment. FIG. 4 is a plan view of the shielding sheet 3 of the radiation shielding body according to this embodiment.

The radiation shield 10 covers a gap 12 formed between two adjacent structures (shielding wall 1 of structure A and shielding wall 2 of structure B). The radiation shielding body 10 includes, for example, a radiation shielding sheet (radiation shielding sheet) 3 that is flexible and can be deformed by its own weight and is stretched between gaps 12 in a flexed state, and a shielding wall that connects the shielding sheet 3 with the radiation shielding sheet 3. 1 and a fixture 4 that is fixed to each of the shielding walls 2.

The shielding sheets 3 are stacked along the vertical direction (the axial direction of the fixture 4), and the plurality of shielding sheets 3 constitute a laminated shielding sheet. Each shielding sheet 3 bends in the gap 12 to form a downwardly convex curved surface, and the width of the portion of each shielding sheet 3 accommodated in the gap 12 is larger than the width W12 of the gap 12. In this embodiment, a high radiation dose device (for example, the main steam pipe 110) is located below the plurality of laminated shielding sheets 3.

The shielding wall 1 and the shielding wall 2 are walls provided in each of two adjacent buildings to shield radiation emitted from high radiation dose equipment, for example, to shield radiation emitted from main steam piping. In order to do this, shielding walls are installed in each of the reactor building and turbine building.

As described above, a gap 12 is provided between the side surface 1a of the shielding wall 1 and the side surface 2a of the shielding wall 2 in order to cope with the relative displacement of the shielding walls 1 and 2 due to an earthquake.

Further, a stepped portion 1d is provided at the corner where the upper surface 1c and the side surface 1a of the shielding wall 1 intersect. The stepped portion 1d has a stepped bottom surface 1e that is substantially parallel to the upper surface 1c, and a stepped side surface 1f that is substantially parallel to the side surface 1a. Further, the corner where the step bottom surface 1e and the side surface 1a intersect is chamfered to form a slope (chamfered portion) 1g.

Furthermore, a stepped portion 2d is provided at the corner where the upper surface 2c and side surface 2a of the shielding wall 2 intersect. The step portion 2d has a shape that is symmetrical to the step portion 1d with respect to the gap 12. The stepped portion 2d has a stepped bottom surface 2e substantially parallel to the upper surface 2c, and a stepped side surface 2f substantially parallel to the side surface 2a. Further, the corner where the step bottom surface 2e and the side surface 2a intersect is chamfered to form a slope 2g (chamfered portion). Note that the chamfers of the slopes 1g and 2g may be curved surfaces instead of slopes.

Although FIG. 3 shows the lower surface 1b of the shielding wall 1 and the lower surface 2b of the shielding wall 2 for convenience, these lower surfaces 1b and 2b may be located lower than shown in the figure. Further, the length L10 (length in the front-rear direction) of the gap 12 may be longer than shown in the drawing.

The shielding sheet 3 is a sheet that suppresses the transmission of radiation, and is, for example, a flexible rectangular rubber sheet made of a polymer impregnated with tungsten, behemoth, and iron. The width W3 of the shielding sheet 3 (see FIG. 4) is larger than the width W12 of the gap 12 between the shielding wall 1 and the shielding wall 2. Moreover, the length L3 (see FIG. 4) of the shielding sheet 3 is substantially the same as the length L10 (see FIG. 3) of the gap 12 between the shielding wall 1 and the shielding wall 2 in this embodiment. Moreover, the thickness of the shielding sheet 3 is preferably thin for the following reasons.

FIG. 5 is a perspective view of a plate-like member and an equation showing the relationship between the thickness and bending rigidity of the plate-like member. As shown in the figure, the bending rigidity k of the plate member is proportional to the moment of inertia I. Further, the moment of inertia I is proportional to the cube of the thickness b of the plate member. From this, the bending rigidity k of the plate member can be reduced by reducing the thickness b. Therefore, it is preferable that the thickness of the shielding sheet 3 is thin.

As shown in FIG. 4, first through holes 3a are provided at each of the four corners of the shielding sheet 3. Among the four first through holes 3a provided at the four corners, the interval DW3 between two adjacent first through holes 3a in the X-axis direction (horizontal direction) is larger than the width W12 of the gap between the shielding wall 1 and the shielding wall 2. It has become.

Further, among the four first through holes 3a provided at the four corners, a second through hole 3b is provided between two adjacent first through holes 3a in the Z-axis direction (front-back direction). Note that the interval between the first through hole 3a and the second through hole 3b adjacent to each other in the front-rear direction is DL3.

As shown in FIG. 3, the fixture 4 is a device that fixes the shielding sheet 3 to the shielding wall 1 and the shielding wall 2. The fixture 4 of this embodiment includes six anchor bolts 4a, two press plates 4b, six nuts 4c, and one guide plate 4d.

Each of the six anchor bolts 4a has one end (base end) embedded in the shielding wall 1 or the shielding wall 2, and the other end (tip part) of a threaded part embedded in the shielding wall 1 or the shielding wall 2. It is a bolt protruding from the

Among the three anchor bolts 4a embedded in the shielding wall 1, one anchor bolt 4a located at the center is provided approximately at the center of the step bottom surface 1e of the step portion 1d of the shielding wall 1. Further, the remaining two anchor bolts 4a are provided at positions spaced apart from the anchor bolt 4a at the center of the step bottom surface 1e by a distance D4 in the front-rear direction.

Among the three anchor bolts 4a embedded in the shielding wall 2, one anchor bolt 4a located in the center is provided approximately at the center of the stepped bottom surface 2e of the stepped portion 2d of the shielding wall 2. Further, the remaining two anchor bolts 4a are provided at positions spaced apart from the anchor bolt 4a at the center of the stepped bottom surface 2e by a distance D4 in the front-rear direction. Therefore, the three anchor bolts 4a provided on the step bottom surface 1e and the three anchor bolts 4a provided on the step bottom surface 2e are symmetrical with respect to the gap 12. Moreover, the distance D4 between two anchor bolts 4a adjacent to each other in the front-rear direction among the six anchor bolts 4a is approximately the same as the distance DL3 between the first through hole 3a and the second through hole 3b of the shielding sheet 3.

The height H1 of the portion of the three anchor bolts 4a provided on the step bottom surface 1e of the shielding wall 1 that protrudes from the step bottom surface 1e is approximately the same as the distance D1 between the upper surface 1c and the step bottom surface 1e. Similarly, the height H2 of the portion of the shielding wall 2 protruding from the step bottom surface 2e is approximately the same as the distance D2 between the upper surface 2c and the step bottom surface 2e. Note that the height H1 may be larger or smaller than the distance D1. Similarly, the height H2 may be larger or smaller than the distance D2.

The two pressing plates 4b are plate-shaped members extending in the length direction of the gap 12, and are made of metal or resin. The length of the two holding plates 4b is longer than the distance (D4×2) of the anchor bolt 4a that is farthest from each other in the front-rear direction among the six anchor bolts 4a. Further, the width of the two pressing plates 4b is smaller than the width W1e in the left-right direction of the step bottom surface 1e and the width W2e in the left-right direction of the step bottom surface 2e, and larger than the diagonal distance between each of the six nuts 4c. ing.

A bolt hole for inserting an anchor bolt 4a is provided in the center of each of the two holding plates 4b. Moreover, further bolt holes are provided at positions spaced apart from the center bolt hole of each of the two holding plates 4b by a distance D4 on both sides in the longitudinal direction.

The six nuts 4c are hexagonal nuts that are screwed onto each of the six anchor bolts 4a. In the example of FIG. 3, a plurality of laminated shielding sheets 3 are located below six nuts 4c. Note that double nuts may be used so that each of the six nuts 4c does not loosen with respect to the anchor bolt 4a.

The guide plate 4d is a flexible member that extends in the width direction of the gap 12, and has a downwardly convex curve that curves toward the bottom at the center in the longitudinal direction (width direction of the gap 12). A portion 4da is provided. The curved portion 4da in FIG. 3 has a curved surface that follows the shape of the shielding sheet 3 that is bent. For example, the curved portion 4da can be formed by bending the rectangular guide plate 4d downward in a convex shape when fixing the guide plate 4d to the two anchor bolts 4a. The length of the guide plate 4d in the longitudinal direction can be set to W3. The width of the guide plate 4d in the longitudinal direction after providing the curved portion 4da is smaller than the interval (W1e+W12+W2e) between the stepped side surface 1f and the stepped side surface 2f. Flat plate portions 4db are provided at both ends of the guide plate 4d in the longitudinal direction, and bolt holes for inserting anchor bolts 4a are provided in each of the flat plate portions 4db. The pitch P4 of the bolt holes in the flat plate portions 4db at both ends is approximately the same as the pitch between two horizontally adjacent anchor bolts 4a of the six anchor bolts 4a.

Note that the curved portion 4da may be formed by bending the rectangular guide plate 4d. The guide plate 4d in this case may be a rigid body without flexibility.

Next, a procedure for installing the radiation shield 10 between the shielding wall 1 and the shielding wall 2 will be explained.

First, insert each of the three through holes 3a and 3b (see FIG. 4) located on the left side (-X side) of the shielding sheet 3 into each of the three anchor bolts 4a protruding from the step bottom surface 1e of the shielding wall 1. do. The distance D4 between two adjacent anchor bolts 4a in the front-rear direction of the step bottom surface 1e is approximately the same as the distance DL3 in the front-rear direction (Z-axis direction) between the first through hole 3a and the second through hole 3b of the shielding sheet 3. ing. Therefore, the left end portion of the shielding sheet 3 is attached to the step bottom surface 1e without loosening.

Next, insert each of the three through holes 3a and 3b (see FIG. 4) located on the right side (+X side) of the shielding sheet 3 into each of the three anchor bolts 4a protruding from the stepped bottom surface 2e of the shielding wall 2. do. The distance D4 between two adjacent anchor bolts 4a in the front-rear direction of the step bottom surface 2e is approximately the same as the distance DL3 in the front-rear direction between the first through hole 3a and the second through hole 3b of the shielding sheet 3. Therefore, the right end portion of the shielding sheet 3 is attached to the step bottom surface 2e without loosening.

On the other hand, the width W3 of the shielding sheet 3 (see FIG. 4) is larger than the width W12 of the gap between the shielding wall 1 and the shielding wall 2 (see FIG. 3). Therefore, the center of the shielding sheet 3 in the left-right direction is slackened downward.

Next, the second shielding sheet 3 is attached on top of the first shielding sheet 3 in the same procedure as the first shielding sheet 3. Further, next, the third shielding sheet 3 is attached on top of the second shielding sheet 3 in the same procedure as the second shielding sheet 3. This procedure is repeated to attach a desired number of shielding sheets 3 between shielding walls 1 and 2. As a result, a plurality of shielding sheets 3 are stacked between the shielding walls 1 and 2.

Next, the guide plate 4d is installed on the plurality of laminated shielding sheets 3. Here, the width of the guide plate 4d in the left-right direction after providing the curved portion 4da is smaller than the interval (W1e+W12+W2e) between the stepped side surface 1f and the stepped side surface 2f. Therefore, the guide plate 4d can be fitted between the stepped side surface 1f and the stepped side surface 2f.

Further, the pitch P4 between the two bolt holes of the guide plate 4d is approximately the same as the pitch between two horizontally adjacent anchor bolts 4a among the six anchor bolts 4a. Therefore, each of the bolt holes provided in the two flat plate parts 4db of the guide plate 4d protrudes from each of the step bottom surface 1e and the step bottom surface 2e so that the guide plate 4d can press the center of the shielding sheet 3 in the front-rear direction. It is fitted into the middle anchor bolt 4a of the three anchor bolts 4a.

The guide plate 4d is installed between the stepped side surface 1f and the stepped side surface 2f similarly to the shielding sheet 3 by providing a curved portion 4da on a plate having approximately the same length as the width W3 in the left-right direction of the shielding sheet 3. There is. Therefore, the shapes of the curved portion 4da of the guide plate 4d and the slack of the shielding sheet 3 are substantially the same. Therefore, by installing the guide plate 4d on the plurality of stacked shielding sheets 3, the curved portion 4da can be brought into close contact with the surface of the shielding sheet 3, so that the shielding sheet 3 can be prevented from loosening.

Next, each of the two pressing plates 4b is installed so as to press both ends of the shielding sheet 3 in the left-right direction and the flat plate portions 4db at both ends of the guide plate 4d. The interval D4 between two adjacent bolt holes among the three bolt holes provided in each of the two holding plates 4b is the distance D4 between two adjacent bolt holes in the front-rear direction of the three anchor bolts 4a protruding from the stepped bottom surfaces 1e and 2e. This is approximately the same as the distance between two anchor bolts 4a. Therefore, each of the three bolt holes provided in each of the two holding plates 4b is fitted into the three anchor bolts 4a protruding from the step bottom surfaces 1e and 2e.

Next, each of the six nuts 4c is tightened to each of the six anchor bolts 4a, and the two presser plates 4b are pressed from above by the six nuts 4c, and the shielding sheet 3 is fixed to each of the shielding wall 1 and the shielding wall 2. do.

[effect]
The radiation shielding body 10 of this embodiment includes a shielding sheet 3 which is stretched across a gap formed by two adjacent structures (shielding wall 1 and shielding wall 2) in a bent state (slack state), and a shielding sheet 3 to the shielding wall 1 and the shielding wall 2. Therefore, even if the width W12 of the gap between the shielding wall 1 and the shielding wall 2 is displaced due to an earthquake or the like, the deflected shielding sheet 3 allows the displacement, and the shielding sheet 3 is placed between the shielding wall 1 and the shielding wall 2. can continue to cover gaps. Moreover, since the radiation shielding body 10 of this embodiment has a simple structure in which the shielding sheet 3 is spanned between two structures, the shape of the concrete wall cannot be complicated as in Patent Document 1. The construction method is easy. Furthermore, it is also easy to add this radiation shield 10 to an existing building for the same reason.

Furthermore, the fixture 4 of the radiation shield 10 of this embodiment includes a plurality of anchor bolts 4a fixed to two adjacent structures, and a plurality of nuts 6 fastened to the plurality of anchor bolts 4a. . Therefore, it is possible to suppress costs and improve durability.

The anchor bolt 4a of this embodiment has stepped portions 1d and 2d (more specifically, a stepped bottom surface 1e) provided on each of two side surfaces 1a and 2a facing each other with a gap 12 in the shielding wall 1 and the shielding wall 2. , 2e). Therefore, the upper end of the radiation shield 10 can be positioned below the upper surfaces 1c and 2c of the shield walls 1 and 2, and the radiation shield 10 can be provided between the shield walls 1 and 2. . This allows the upper surface 1c and the upper surface 2c to be substantially one plane free of obstacles.

The radiation shielding body 10 of this embodiment has a plurality of shielding sheets 3, and the plurality of shielding sheets 3 are stacked. Therefore, the number of shielding sheets 3 can be changed depending on the radiation dose emitted from the high radiation dose instrument.

In the radiation shielding body 10 of this embodiment, the shielding sheet 3 is detachable from the upper surface side of the shielding wall 1 and the shielding wall 2 (the side opposite to the direction in which the high radiation dose instrument is located). Therefore, maintenance work for the radiation shield 10 and the like can be performed while suppressing the amount of radiation exposure of the worker.

The radiation shield 10 of this embodiment has surfaces of the shielding walls 1 and 2 that are in contact with the shielding sheet 3 (step bottom surfaces 1e, 2e), and opposing surfaces of the shielding walls 1 and 2 (side surfaces 1a, 2a). Chamfered portions 1g and 2g are provided at the corners where the two intersect. Therefore, it is possible to reduce the possibility that the shielding sheet 3 will be damaged by the corner where the step bottom surfaces 1e, 2e intersect with the side surfaces 1a, 2a.

The radiation shielding body 10 of this embodiment is a flexible plate-like member, and includes a guide plate 4d having a curved portion 4da formed in the center in the longitudinal direction. Therefore, by installing the guide plate 4d on the shielding sheet 3, the curved portion 4da can be brought into close contact with the surface of the shielding sheet 3, and the shielding sheet 3 can be fixed.

(Second embodiment)
FIG. 6 is a perspective view of the radiation shield 20 according to the second embodiment. The radiation shielding body 20 according to this embodiment differs from the radiation shielding body 10 according to the first embodiment in that it includes a water stop joint 21 that spans the gap 12 so as to overlap the shielding sheet 3.

Note that, like FIG. 3, FIG. 6 shows the lower surface 1b of the shielding wall 1 and the lower surface 2b of the shielding wall 2 for convenience, but these lower surfaces 1b and 2b are located lower than shown in the figure. Sometimes. Further, the length L20 (length in the front-rear direction) of the gap 12 may be longer than illustrated.

The water stop joint 21 is a flexible water stop connection device that absorbs the displacement of the attached structure by deforming it, and can suppress water intrusion between the structure and the joint by being compressed. It must be placed in close contact with the shielding wall 2. Therefore, the water stop joint 21 is attached to the step bottom surface 1e and the step bottom surface 2e of the shielding wall 2 before the shielding sheet 3 is attached to the step bottom surface 1e of the shielding wall 1 and the step bottom surface 2e of the shielding wall 2.

Note that the water stop joint 21 may be removed from the shielding wall 1 and the shielding wall 2 for maintenance. The water stop joint 21 is attached to the plurality of anchor bolts 4a of the fixture 4, and is fixed by tightening the plurality of nuts 4c fastened to the plurality of anchor bolts 4a. Therefore, in the radiation shielding body 20 of this embodiment, the water stop joint 21 can be easily removed.

[effect]
Since the radiation shielding body 20 of this embodiment includes the water stop joint 21, it is possible to suppress rainwater and the like from entering through the gap between the shielding wall 1 and the shielding wall 2.

(Third embodiment)
FIG. 7 is a perspective view of a radiation shield 30 according to the third embodiment. The radiation shield 30 according to the present embodiment differs from the radiation shield 10 according to the first embodiment in the length L30 of the gap between the shield wall 1 and the shield wall 2 and the configuration of the fixture 4. .

Note that, like FIG. 3, FIG. 7 shows the lower surface 1b of the shielding wall 1 and the lower surface 2b of the shielding wall 2 for convenience, but these lower surfaces 1b and 2b are located lower than shown in the figure. Sometimes. Further, the length L30 (length in the front-rear direction) of the gap 12 may be longer than illustrated.

The length L30 of the gap between the shielding wall 1 and the shielding wall 2 in this embodiment is larger than the length L3 of the shielding sheet 3 (see FIG. 4). Therefore, in the radiation shield 10 according to the first embodiment, the gap between the shield wall 1 and the shield wall 2 cannot be shielded.

Therefore, in this embodiment, a plurality of shielding sheets 3 are shifted in the front-back direction and lined up without any gaps, thereby shielding the gaps between the shielding walls 1 and 2. Therefore, the sum of the lengths L3 of the plurality of shielding sheets 3 arranged between the shielding walls 1 and 2 is larger than the length L30 of the gap between the shielding walls 1 and 2.

Furthermore, the fixture 4 of this embodiment differs from the first embodiment in the number of anchor bolts 4a, nuts 4c, and guide plates 4d, and the form of the two holding plates 4b.

There are ten anchor bolts 4a in this embodiment, and five anchor bolts are provided on each of the step bottom surface 1e of the step portion 1d of the shielding wall 1 and the step bottom surface 2e of the step portion 2d of the shielding wall 2. Note that, of the five anchor bolts 4a provided on each of the step bottom surface 1e and the step bottom surface 2e, the distance between two anchor bolts 4a adjacent in the front-rear direction is D4 as in the first embodiment. Furthermore, the number of nuts 4c is ten, which is the same as the number of anchor bolts 4a, and the number of guide plates 4d is two.

In addition, since the length of the gap between the shielding wall 1 and the shielding wall 2 and the number of anchor bolts 4a and nuts 4c of this embodiment are different from the first embodiment, the length of the two holding plates 4b and the number of bolt holes are different from those of the first embodiment. The number is also different from the first embodiment. That is, the length of each of the two holding plates 4b is determined by the distance (D4× 4) is larger. Furthermore, five bolt holes are provided in each of the two holding plates 4b such that the distance between two bolt holes adjacent to each other in the longitudinal direction is D4. In addition, each of the two presser plates 4b can be divided into plates each having one or more bolt holes and used as a plurality of plates.

Next, a procedure for providing the radiation shield 30 between the shielding wall 1 and the shielding wall 2 will be explained.

First, insert each of the three through holes 3a and 3b (see FIG. 4) located on the left side (-X side) of the shielding sheet 3 into the front three of the five anchor bolts 4a protruding from the step bottom surface 1e. do. The distance D4 between the anchor bolts 4a adjacent to each other in the front-rear direction of the stepped bottom surface 1e is approximately the same as the distance DL3 between the first through-hole 3a and the second through-hole 3b adjacent to each other in the front-rear direction of the shielding sheet 3. Therefore, the left end portion of the shielding sheet 3 is attached to the step bottom surface 1e without loosening.

Next, each of the three through holes 3a and 3b (see FIG. 4) located on the right side (+X side) of the shielding sheet 3 is inserted into the front three of the five anchor bolts 4a protruding from the step bottom surface 2e. . The distance D4 between the anchor bolts 4a adjacent to each other in the front-rear direction of the stepped bottom surface 2e is approximately the same as the distance DL3 between the first through-hole 3a and the second through-hole 3b adjacent to each other in the front-rear direction of the shielding sheet 3. Therefore, the right end portion of the first shielding sheet 3 is attached to the step bottom surface 2e without loosening.

Next, each of the three through holes 3a and 3b located on the left side of the second shielding sheet 3 is inserted into the rear three of the five anchor bolts 4a protruding from the step bottom surface 1e. At this time, the first shielding sheet 3 has already been inserted into the anchor bolt 4a at the center of the stepped bottom surface 1e. Therefore, two shielding sheets 3 are inserted into the anchor bolt 4a at the center of the stepped bottom surface 1e.

The distance D4 between the anchor bolts 4a adjacent to each other in the front-rear direction of the stepped bottom surface 1e is approximately the same as the distance DL3 between the first through-hole 3a and the second through-hole 3b adjacent to each other in the front-rear direction of the shielding sheet 3. Therefore, the left end portion of the second shielding sheet 3 is attached to the step bottom surface 1e without loosening.

Next, each of the three through holes 3a and 3b located on the right side of the second shielding sheet 3 whose left end is attached to the step bottom surface 1e is connected to the rear side of the five anchor bolts 4a protruding from the step bottom surface 2e. Insert it into three places. At this time, the first shielding sheet 3 has already been inserted into the anchor bolt 4a at the center of the stepped bottom surface 2e. Therefore, two shielding sheets 3 are inserted into the anchor bolt 4a at the center of the stepped bottom surface 2e.

The distance D4 between the anchor bolts 4a adjacent to each other in the front-rear direction of the stepped bottom surface 2e is approximately the same as the distance DL3 between the first through-hole 3a and the second through-hole 3b adjacent to each other in the front-rear direction of the shielding sheet 3. Therefore, the right end portion of the second shielding sheet 3 is attached to the step bottom surface 2e without loosening.

In this way, the two shielding sheets 3 attached to the step bottom surface 1e and the step bottom surface 2e overlap at the center in the front-rear direction between the shielding wall 1 and the shielding wall 2. Therefore, the gap between the shielding wall 1 and the shielding wall 2 can be shielded.

Next, the third shielding sheet 3 is attached in the same procedure as the first shielding sheet 3, and the fourth shielding sheet 3 is attached in the same procedure as the second shielding sheet 3. This procedure is repeated to attach a desired number of shielding sheets 3 between shielding walls 1 and 2. Thereby, the gap between the shielding wall 1 and the shielding wall 2 is shielded by a plurality of stacked shielding sheets 3 as shown in FIG.

Next, two guide plates 4d are installed on the plurality of laminated shielding sheets 3. First, each of the bolt holes provided in the two flat plate parts 4db of the first guide plate 4d is connected to the step bottom surface 1e so as to press the center of the plurality of shielding sheets 3 stacked on the front side in the front-rear direction. It is fitted into the second anchor bolt 4a from the front among the five anchor bolts 4a protruding from each of the bottom surfaces 2e.

Next, each of the bolt holes provided in the two flat plate parts 4db of the second guide plate 4d is inserted into the stepped bottom surface 1e so as to press the center of the plurality of shielding sheets 3 stacked on the rear side in the front-rear direction. It is fitted into the second anchor bolt 4a from the rear of the five anchor bolts 4a protruding from each of the stepped bottom surfaces 2e.

Note that the guide plate 4d may be attached to other locations. For example, in order to press the overlapping portion of the first shielding sheet 3 and the second shielding sheet 3, bolt holes provided in the two flat plate parts 4db of the guide plate 4d are connected to the stepped bottom surface 1e and the stepped bottom surface. It may be fitted into the central anchor bolt 4a in the front-rear direction among the five anchor bolts 4a protruding from each of the anchor bolts 2e. Further, the number of guide plates 4d may not be two, but may be another number, such as one or three.

Next, each of the two pressing plates 4b is installed so as to press both ends of the shielding sheet 3 in the left-right direction and the flat plate portions 4db at both ends of the two guide plates 4d. The distance D4 between two adjacent bolt holes of the five bolt holes provided in each of the two holding plates 4b is the distance D4 between two adjacent bolt holes in the front-rear direction among the five anchor bolts 4a protruding from the stepped bottom surfaces 1e and 2e. The spacing is approximately the same as the spacing between anchor bolts 4a. Therefore, each of the five bolt holes provided in each of the two holding plates 4b is fitted into the five anchor bolts 4a protruding from the step bottom surfaces 1e and 2e.

Next, each of the ten nuts 4c is tightened to each of the ten anchor bolts 4a, and the two pressing plates 4b are pressed down from above to fix the shielding sheet 3 to each of the shielding wall 1 and the shielding wall 2.

[effect]
In the radiation shielding body 30 of this embodiment, the sum of the lengths L3 of the plurality of shielding sheets 3 arranged between the shielding walls 1 and 2 is the length L30 of the gap between the shielding walls 1 and 2. bigger. Therefore, by shifting the plurality of shielding sheets 3 in the front-rear direction and arranging them without gaps, the gap between the shielding walls 1 and 2 can be shielded.

In this embodiment, as shown in FIGS. 7 and 8, the two shielding sheets 3 attached to the step bottom surface 1e and the step bottom surface 2e are attached to the anchor bolts 4a at the center of the step bottom surface 1e and the step bottom surface 2e. A configuration is shown in which two first through holes 3a overlap in a certain zone. However, it is not limited to this. For example, as shown in FIG. 9, the two shielding sheets 3 are long, and among the five anchor bolts 4a protruding from each of the step bottom surface 1e and the step bottom surface 2e, the second two anchor bolts 4a from the front, The two central anchor bolts 4a and the through holes 3a and 3b attached to the second anchor bolt 4a from the back may overlap in a certain region.

In addition, as shown in FIG. 10, in order to cope with the case where the length of the gap between the shielding wall 1 and the shielding wall 2 is even longer, three shielding sheets 3 are lined up between the step bottom surface 1e and the step bottom surface 2e. The gap between the shielding wall 1 and the shielding wall 2 may be shielded, or the gap between the shielding wall 1 and the shielding wall 2 may be shielded by lining up four or more shielding sheets 3.

In addition, by increasing the number of anchor bolts 4a and second through holes 3b in the front-rear direction and narrowing the interval between them, the gap between two adjacent shielding sheets 3 in the front-rear direction can be reduced, as shown in FIG. However, the shielding sheets 3 may be arranged in such a way that the shielding properties are improved.

In addition, as described above, by increasing the number of anchor bolts 4a and second through holes 3b and narrowing the distance between them, using shielding sheets 3 of different lengths, as shown in FIG. The shielding sheets 3 may be arranged so that the positions of the band-shaped gaps (gaps 3c) between two adjacent shielding sheets 3 do not overlap in the vertical direction, and the shielding properties are further improved.

That is, in the radiation shielding body 30 according to this embodiment, the plurality of shielding sheets 3 are provided with voids 3c between two adjacent shielding sheets 3 of the same layer, and the arrangement of the voids 3c is different between adjacent layers. Therefore, the radiation shielding body 30 according to this embodiment can improve shielding performance.

(Fourth embodiment)
FIG. 13 is a perspective view of a radiation shield 40 according to the fourth embodiment. The radiation shielding body 40 according to the present embodiment is different from the radiation shielding body 10 according to the first embodiment in that the shielding walls 1 and 2 do not have stepped portions 1d and 2d, and the upper surfaces 1c and 2c of the shielding walls 1 and 2 have no stepped portions 1d and 2d. This is because the radiation shield 40 is not provided.

Note that, like FIG. 3, FIG. 13 shows the lower surface 1b of the shielding wall 1 and the lower surface 2b of the shielding wall 2 for convenience, but these lower surfaces 1b and 2b are located lower than shown in the figure. Sometimes. Further, the length L40 (length in the front-rear direction) of the gap 12 may be longer than illustrated.

[effect]
Since the radiation shield 40 of this embodiment does not provide the step portions 1d and 2d on the shielding walls 1 and 2, it can be easily added to an existing structure.

Note that the present invention is not limited to the embodiments described above, and includes various modifications. For example, the embodiments described above have been described in detail to explain the present invention in an easy-to-understand manner, and the present invention is not necessarily limited to having all the configurations described. Furthermore, it is possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. Furthermore, it is possible to add, delete, or replace some of the configurations of each embodiment with other configurations.

Note that the embodiment of the present invention may have the following aspects. That is, the radiation shielding body according to each embodiment has a mode of covering the gap formed between two structures from above (i.e., a mode of covering the top surface of the structure), but a mode of covering the gap from the side (i.e., a mode of covering the top surface of the structure). A mode in which the side surface of the structure is covered) or a mode in which the gap is covered from below (that is, a mode in which the bottom surface of the structure is covered) may be adopted.

Further, the structure to which the radiation shielding body 10 is attached is preferably a rigid body having a radiation shielding function, such as concrete or reinforced concrete.

Moreover, the number and the position of the second through holes 3b of the shielding sheet 3 in the front-rear direction may be not limited to the above-mentioned configuration but may be other configurations. Similarly, the number of anchor bolts 4a and their positions in the front-rear direction may be changed not only to the above-mentioned configuration but also to other configurations. In this case, the number of second through holes 3b of the shielding sheet 3 and the position in the front-back direction and the number of anchor bolts 4a and the position in the front-rear direction are correlated, and each needs to be determined based on the value. Furthermore, the procedure for attaching the shielding sheet 3 is not limited to the above.

1, 2... Shielding wall, 1a, 2a... Side surface, 1c, 2c... Top surface, 1d, 2d... Step, 1e, 2e... Step bottom, 1f, 2f... Step side, 1g, 2g... Slope, 3... Shielding sheet. 3a...first through hole, 3b...second through hole, 3c...gap, 4...fixing tool, 4a...anchor bolt, 4b...pressing plate, 4c...nut, 4d...guide plate, 4da...curved portion, 4db...flat plate Part, 10, 20, 30, 40...Radiation shield, 12...Gap, 21...Water stop joint

Claims (11)

A radiation shield covering a gap between two adjacent structures,
a radiation shielding sheet that is flexible and spans the gap in a flexed state;
A radiation shielding body comprising: a fixture for fixing the shielding sheet to the two adjacent structures. The radiation shield according to claim 1,
A radiation shield characterized in that the fixing device includes a plurality of anchor bolts fixed to the two adjacent structures and a plurality of nuts fastened to the plurality of anchor bolts. The radiation shield according to claim 1,
A radiation shield, wherein the shielding sheet is a plurality of laminated shielding sheets. The radiation shield according to claim 1,
A radiation shielding body characterized in that the shielding sheet is detachable from predetermined sides of the two adjacent structures. The radiation shield according to claim 1,
A radiation shield comprising a flexible guide plate having a curved portion at the center in the width direction of the gap. The radiation shield according to claim 1,
A radiation shielding body comprising a water-stop joint spanning the gap so as to overlap with the shielding sheet. The radiation shield according to claim 3,
A radiation shielding body characterized in that the sum of the lengths of the plurality of shielding sheets arranged between the two adjacent structures is greater than the length of the gap between the two adjacent structures. The radiation shield according to claim 3,
The plurality of shielding sheets include a gap between two adjacent shielding sheets of the same layer,
A radiation shield characterized in that the arrangement of the voids is different between adjacent layers. The radiation shield according to claim 2,
The radiation shield, wherein the anchor bolts are fixed to surfaces of the two adjacent structures. The radiation shield according to claim 2,
The radiation shielding body is characterized in that the anchor bolt is fixed to a stepped portion provided on each of two side surfaces of the two adjacent structures that face each other across the gap. The radiation shield according to claim 1,
A chamfered portion is provided at a corner where surfaces of the two adjacent structures in contact with the shielding sheet intersect with two side surfaces of the two adjacent structures facing each other across the gap. radiation shield.

Images