JP7340245B2 - Radiation shielding method, radiation shielding structure, clay with lead beads - Google Patents

Description

The present invention relates to radiation shielding technology.

There are radiation devices that emit radiation for various purposes. Radiology equipment includes X-ray imaging equipment that irradiates patients with X-rays for image diagnosis of lesions, radiation therapy equipment that irradiates X-rays and gamma rays to affected areas for treatment, and x-ray equipment that irradiates X-rays and gamma rays to affected areas for treatment of diseased areas. There are X-ray diffractometers and the like that irradiate a sample with X-rays for analysis by ray diffraction. In a radiation equipment room where radiation equipment is installed, it is necessary to shield the room from radiation.

As a radiation shielding method, there is a method of providing a wall with a hollow interior and filling the inside of the wall with a radiation shielding member (for example, Patent Document 1).

Japanese Patent Application Publication No. 9-211169

The above method has a problem in that the wall production is very costly and time consuming. A generally known radiation shielding method is to provide a radiation shielding lead plate indoors.

FIG. 1 is a perspective view showing lead plates 21, 22, 100 for shielding radiation.
When the lead plates 21 and 22 are used indoors to shield radiation, a gap 23 is created between the lead plates 21 and 22. In order to prevent leakage of radiation from the gap 23, a lead plate 100 is installed on one of the lead plates 21 and 22 so as to cover the gap 23. The lead plate 100 is constructed by stacking a plurality of lead plates 100A to 100C with a predetermined thickness depending on the required shielding amount of radiation corresponding to the gap 23. The lead plates 100A to 100C are adhered with tape or the like. The base lead plate 100A is wider than the stacked lead plates 100B and 100C. In order to reduce the amount of lead plates used, the lead plates 100C in the upper layer have shorter widths.

This method has a problem in that a plurality of lead plates 100A to 100C having different widths must be produced.

FIG. 2 is a perspective view showing lead plates 21, 22, 110 for shielding radiation.
In order to prevent leakage of radiation from the gap 23, it is conceivable to use a lead plate 110 having a thickness corresponding to the assumed maximum size of the gap 23. In this case, there is a problem in that the weight of the lead plate 110 becomes larger than necessary, resulting in a large disadvantage in production and transportation.

An object of the present invention is to provide a radiation shielding technique using a radiation shielding member that is easy to produce and transport.

The gist of the invention is as follows.
(1) Mix multiple lead balls with clay to create clay containing lead balls,
Filling the gap in the radiation shielding wall with the clay containing lead balls,
A radiation shielding method comprising curing the lead ball-containing clay and shielding radiation in the gap by the lead ball-containing clay.
(2) The radiation shielding method according to (1), wherein the clay is a mixture of two agents: an epoxy resin prepolymer and a curing agent.
(3) Mix multiple lead balls with clay to create clay containing lead balls,
Applying the clay containing lead balls on the wall,
A radiation shielding method comprising curing the lead ball-containing clay and shielding radiation by the lead ball-containing clay.
(4) Mix multiple lead balls with clay to generate lead ball-containing clay;
Laminating the lead ball-containing clay on an area including a curved surface on the outer surface of the casing,
A radiation shielding method comprising curing the lead ball-containing clay and shielding the article from radiation by the lead ball-containing clay.
(5) Mix multiple lead balls with clay to generate lead ball-containing clay;
Laminating the clay containing lead balls over the entire outer surface of the article,
A radiation shielding method comprising curing the lead ball-containing clay and shielding the article from radiation by the lead ball-containing clay.
(6) Mix multiple lead balls with clay to generate lead ball-containing clay;
A radiation shielding method comprising pouring the lead ball-containing clay into a mold and shielding radiation by the lead ball-containing clay.
(7) The radiation shielding method according to any one of (3) to (6), wherein the clay is liquid clay.
(8) The radiation shielding method according to any one of (1) to (7), wherein the lead ball has a diameter of 0.1 to 0.5 mm.
(9) a radiation shielding wall having a gap;
Clay containing lead balls, which includes clay and a plurality of solid lead balls mixed with the clay, fills the gap, and shields radiation in the gap;
A radiation shielding structure equipped with.
(10) Clay containing lead balls, which includes clay and a plurality of solid lead balls mixed with the clay, and which is capable of shielding radiation in the gap by being filled into a gap in a radiation shielding wall and hardening.
(11) A lead ball-containing clay comprising clay and a plurality of solid lead balls mixed with the clay, hardened to cover the entire outer surface of the article, and shielding the article from radiation.
(12) Mix multiple lead balls with clay to produce clay containing lead balls,
Pour the clay containing lead balls into the box body from the opening of the box body,
A shielding member manufacturing method for manufacturing a shielding member that blocks radiation by closing the opening with a closing member.
(13) Clay containing lead balls, which includes clay and a plurality of solid lead balls mixed into the clay;
A radiation shielding member comprising: a box-shaped member that accommodates the lead ball-containing clay inside.

FIG. 3 is a perspective view showing lead plates 21, 22, and 100 for shielding radiation in a conventional example. It is a perspective view showing lead plates 21, 22, and 110 for shielding radiation in a conventional example. It is a figure showing radiation shielding structure 1 using clay 3 containing lead balls in a 1st embodiment. It is a figure showing radiation shielding structure 1A in a 2nd embodiment. It is a figure showing radiation shielding structure 1B in a 3rd embodiment. It is a figure showing radiation shielding structure 1C in a 4th embodiment. It is a sectional view of a housing 41 in which lead ball-containing clay 3D is laminated in a fifth embodiment. FIG. 3 is a cross-sectional view of a structure in which a housing 41 is covered with lead plates 120 to 122 in a conventional example. It is a sectional view of clay 3E containing lead balls laminated on article 42 in a sixth embodiment. It is a sectional view of radiation shielding member 8 in a 7th embodiment. It is a sectional view for explaining the radiation shielding method in an 8th embodiment.

Hereinafter, embodiments will be described with reference to the drawings.
(First embodiment)
The clay 3 containing lead balls shown in FIG. 3(B) can be used as a shielding member for radiation such as X-rays, gamma rays, and beta rays. The lead ball-containing clay 3 is produced by mixing a plurality of lead balls 31 into clay 32, as shown in FIG. 3(A). The lead ball 31 is solid and has a diameter approximately equal to a predetermined value within the range of 0.1 to 0.5 mm. The diameter of the lead ball 31 is preferably 0.1 to 0.5 mm. If the diameter of the lead balls 31 is 0.5 mm or less, the lead balls 31 can be arranged sufficiently densely, and the radiation shielding ability of the lead ball-containing clay 3 can be improved. If the lead ball 31 has a diameter of 0.1 mm or more, a commercially available lead ball 31 can be used (lead balls 31 with a diameter smaller than 0.1 mm are special and difficult to obtain).

Any suitable material can be used as the clay 32 as long as it can be mixed with the lead balls 31, can be filled into gaps and holes in the wall, and hardens after being filled. The clay 32 can also be referred to as adhesive or putty. Here, an example in which epoxy clay is used as the clay 32 will be described. The clay 32 is a mixture of two components: an epoxy resin prepolymer and a curing agent. The clay 32 may also be a rubber material, and the lead balls 31 may be added to the rubber (clay 32) during the manufacturing process. The clay 32 may also be a thermoplastic polyethylene resin or other resin, which becomes soft and fluid at temperatures higher than the glass transition point (melting point) and solidifies at temperatures lower than the glass transition point. There may be. Any suitable material can be used as the clay 32. In this embodiment, the clay 32 used is one that can be kneaded and can hold a three-dimensional shape.

The density of the lead balls 31 relative to the clay 32 is preferably 60% or more from the viewpoint of ensuring sufficient radiation shielding ability. The density of the lead balls 31 may be adjusted to a preferable value depending on the usage pattern of the lead ball-containing clay 3. For example, when painting the clay containing lead balls 3A, 3D on the wall 11 (second embodiment) or when laminating it on the casing 41 (fifth embodiment), the density of the lead balls 31 is may be adjusted to a value that allows good adhesion to the wall portion 11 or the casing 41.

FIG. 3(C) is a cross-sectional view showing the radiation shielding structure 1.
The radiation shielding structure 1 is a wall structure of a radiation device room in which a radiation device such as a dental X-ray imaging device is installed. In the radiation shielding structure 1, lead plates 21 and 22 are provided on the indoor side of the walls 11 and 12 of the radiation equipment room by adhesion with tape or the like as shielding walls for radiation such as X-rays. Thereby, in the radiation shielding structure 1, leakage of radiation to the outside is prevented.

Here, at the inner corners of the wall portions 11 and 12, the lead plates 21 and 22 are adjacent to each other in a posture perpendicular to each other. A gap 23 is formed between the lead plates 21 and 22 along the direction perpendicular to the plane of the drawing in FIG. 3(C) due to a joint between the lead plates 21 and 22. In this case, there is a risk that radiation may leak from the gap 23 to the outside.

Therefore, a worker mixes two agents, an epoxy resin prepolymer and a hardening agent, to produce clay 32 on site. Then, the worker mixes a plurality of lead balls 31 into this clay 21 to produce lead ball-containing clay 3.

Subsequently, the worker fills the entire gap 23 between the lead plates 21 and 22 with the clay 3 containing lead balls before hardening the clay 3 containing lead balls. The worker hardens the lead ball-containing clay 3 by leaving the lead ball-containing clay 3 for a hardening time set for the clay 32 or by heating the lead ball-containing clay 3 to a set temperature.

In this embodiment, the clay 3 containing lead balls can shield radiation in the gap 23 and prevent radiation from leaking from the gap 23 to the outside. In this embodiment, clay 3 containing lead balls is used as the radiation shielding member, and the clay 3 containing lead balls can be produced using commercially available clay 32 and lead balls 31.

Conventionally, lead plates 100 and 110 (FIGS. 1 and 2) have been provided as radiation shielding members in the gap 23, and the lead plates 100 and 110 are large and difficult to transport. In this embodiment, the lead ball-containing clay 3 is used as a shielding member for the gap 23. Since the lead ball-containing clay 3 only needs to fill the gap 23, the required volume of the gap 23 as a radiation shielding member is made smaller than before. This can be significantly reduced.

In addition, since the raw materials clay 32 and lead balls 31 have indeterminate shapes, they can be placed in a suitable container and easily transported to the site. Furthermore, the clay 32 is lighter than lead. From the above, the lead ball-containing clay 3 (clay 32 and lead balls 31) as a shielding member for the gap 23 is much easier to transport to the site than the conventional ones (lead plates 100, 110).

In this embodiment, it is sufficient to fill the gap 23 with clay 3 containing lead balls, which is extremely lightweight, so construction is much easier than in the past. In this embodiment, a slurry-like clay containing lead balls 3A, which will be described later, may be used.

(Second embodiment)
FIG. 4(B) is a diagram showing the radiation shielding structure 1A.
In the radiation shielding structure 1A, clay containing lead balls 3A is applied to the indoor side of the wall 11 of the radiation equipment room, and the layer of clay containing lead balls 3A prevents leakage of radiation to the outside.

As shown in FIG. 4(A), lead ball-containing clay 3A is produced by mixing lead balls 31A with diameters approximately equal to a predetermined value within the range of 0.1 to 0.5 mm into clay 32A. The clay 32A is a milky synthetic resin emulsion clay in which fine particles of a water-insoluble synthetic resin are dispersed and mixed in water. The plasticity of the synthetic resin emulsion clay is lower than the plasticity of the epoxy clay of the first embodiment. The clay 32A may be any liquid clay that has fluid properties before solidifying, and may include synthetic resin emulsion clay, epoxy resin, synthetic resin, acrylic resin, urethane resin, silicone resin, etc. A liquid agent (liquid clay) such as a fluororesin-based material may also be used. The liquid agent (liquid clay) may be a one-liquid agent or a two-liquid agent in which a hardening agent is mixed with the main agent. The same applies to the following embodiments.

The worker puts the clay 32A and the lead balls 31A into a bucket 91, for example, and mixes the clay 32A and the lead balls 31A with a spatula 92 or the like at the site to generate a slurry-like clay 3A containing lead balls. As shown in FIG. 4(B), the worker applies clay 3A containing lead balls to the indoor side of the wall 11 of the radiation equipment room using a spatula 92 or the like. The worker hardens the lead ball-containing clay 3A by leaving the lead ball-containing clay 3A to dry, and forms a layer of the lead ball-containing clay 3A on the wall portion 11. The thickness of the layer may be adjusted depending on the amount of radiation irradiated and the degree to which leakage of radiation is desired to be prevented, and may be set according to the purpose.

In this embodiment, radiation can be shielded by the layer of clay 3A containing lead balls on the wall portion 11. By forming the lead ball-containing clay 3A over the entire indoor side of the wall portion 11, a layer of the lead ball-containing clay 3A can be formed as a radiation shielding member instead of the lead plates 21 and 22. Formation of the layer of lead ball-containing clay 3A can be done simply by applying the lead ball-containing clay 3A to the wall portion 11 using a spatula 92 or the like, and construction is easy. This embodiment also has the advantage that commercially available clay 32A and lead balls 31A can be used as raw materials for the lead ball-containing clay 3A, and that production is easy and that clay 32A and lead balls 31A are easy to transport to the site. Note that "shielding radiation" may be described as meaning reducing the amount of radiation passing through, in addition to completely shielding radiation.

(Third embodiment)
FIG. 5 is a diagram showing the radiation shielding structure 1B.
The radiation shielding structure 1B includes an R-shaped wall 11B, which is a side wall, as the wall 11 of the radiation equipment room. The lead plates 21 and 22 cannot be attached to the outer curved surface of a rounded or circular object, and cannot be attached to the R-shaped wall portion 11B. Therefore, conventionally, it has been difficult to provide a shielding member on the R-shaped wall portion 11B.

In this embodiment, clay containing lead balls 3B is provided on the R-shaped wall portion 11B as a radiation shielding member. In this embodiment, the lead ball-containing clay 3B is a slurry-like product in which lead balls are mixed with liquid clay, which is an epoxy resin-based liquid, for example, so that it can be applied and easily provided on the wall portion 11B. Note that the lead ball-containing clay 3B may be made by mixing lead balls in epoxy clay or the like that can maintain a three-dimensional shape. In this case, the lead ball-containing clay 3B also has the ability to follow the external shape of the wall portion 11B. Since it has a good quality, it can be easily provided on the wall portion 11B. In this embodiment, the layer of clay 3B containing lead balls in the R-shaped wall portion 11B can prevent radiation from leaking to the outside.

FIG. 5 shows a state in the middle of the installation work of the lead ball-containing clay 3B on the wall portion 11B. As the lead ball-containing clay 3B, any suitable clay can be used as long as lead balls and clay are mixed. It is preferable to use iron balls whose diameters are approximately equal to a predetermined value within the range of 0.1 to 0.5 mm. The flat wall portion 11 may be provided with lead plates 21, 22 as radiation shielding members, or clay containing lead balls 3, 3A, 3B may be provided. When the lead plates 21 and 22 are provided, the joint between the lead plates 21 and 22 may be filled with clay 3 containing lead balls.

(Fourth embodiment)
FIG. 6 is a diagram showing the radiation shielding structure 1C.
In the radiation shielding structure 1C, a ceiling wall 11C has a dome shape, and clay containing lead balls 3C is provided on the wall 11C as a radiation shielding member. FIG. 6 shows a state in the middle of the installation work of the lead ball-containing clay 3C on the wall portion 11C. The clay containing lead balls 3C is a slurry of liquid clay mixed with lead balls so that it can be easily applied. Note that the lead ball-containing clay 3C may be a mixture of epoxy clay or the like that can maintain a three-dimensional shape with lead balls mixed therein.

In this embodiment as well, in the dome-shaped wall portion 11C, the layer of clay containing lead balls 3C can prevent radiation from leaking to the outside. The flat wall portion 11 may be provided with lead plates 21, 22 or clay containing lead balls 3, 3A to 3C as radiation shielding members.

(Fifth embodiment)
FIG. 7 is a cross-sectional view of the casing 41 in which the lead ball-containing clay 3D is laminated.
In the radiation shielding method (method for manufacturing a radiation shielding structure) of this embodiment, a worker first mixes a plurality of lead balls into clay to generate lead ball-containing clay 3D. The lead ball-containing clay 3D is a slurry of liquid clay mixed with lead balls, but it is also possible to use epoxy clay or the like that can hold a three-dimensional shape with lead balls mixed therein.

Subsequently, the worker applies and laminates the lead ball-containing clay 3D on the area including the curved surface portion 411 on the outer surface of the casing 41 (article). When using clay 3D containing lead balls using epoxy clay or the like, the clay 3D containing lead balls may be attached directly to the outer surface of the casing 41, or may be attached to the outer surface of the casing 41 using adhesive, tape, etc. . The same applies to the third and fourth embodiments when lead ball-containing clays 3B and 3C using epoxy clay or the like are used.

Examples of the housing include a housing 41 of a device expected to be used in a radiation equipment room, a housing 41 of a device that emits radiation, and a housing 41 of a nuclear reactor, for example. Note that it is particularly effective to stack the lead ball-containing clay 3D on a region of the outer surface of the casing 41 that includes the curved surface portion 411, but it may also be stacked on a region of the outer surface of the casing 41 that includes only the flat portion.

Subsequently, the worker hardens the lead ball-containing clay 3D by drying or the like to form a layer of the lead ball-containing clay 3D on the casing 41. In this embodiment, the clay 3D containing lead balls blocks radiation to the housing 41.

As shown in FIG. 8, conventionally, when covering the casing 41 with lead plates 120 to 122, the lead plates 120 to 122 are attached to the outer surface of the casing 41. At the joints between adjacent lead plates 120 to 122, for example, the ends of the lead plates 120 to 122 are overlapped to prevent radiation leakage. For example, the ends of the lead plate 122 on the curved surface portion 411 are stacked on the ends of the lead plates 120 and 121 on both sides. In this configuration, the lead plate 122 on the curved surface portion 411 has poor followability to the curved surface portion 411, has an uneven shape, and a gap is created between the lead plate 122 and the curved surface portion 411, and the radiation shielding ability is reduced.

In this embodiment, since clay 3D containing lead balls is used as a radiation shielding member, productivity and transportability are good as described above. Furthermore, since the lead ball-containing clay 3D has good followability to the curved surface portion 411, radiation can be shielded better by constructing the lead ball-containing clay 3D than by installing the lead plates 120 to 122.

(Sixth embodiment)
9(A) is a cross-sectional view of the lead ball-containing clay 3E laminated on the article 42, and FIG. 9(B) is a cross-sectional perspective view of the lead ball-containing clay 3E laminated on the article 42.
In the radiation shielding method of this embodiment, a worker first mixes a plurality of lead balls into clay to produce lead ball-containing clay 3E.

Subsequently, the worker laminates the lead ball-containing clay 3E over the entire outer surface of the article 42. The article 42 is exemplified as having a spherical shape in this embodiment, but any appropriate article can be used. When using a slurry of liquid clay mixed with lead balls as the lead ball-containing clay 3E, by immersing the article 42 in the lead ball-containing clay 3E in a container, the lead ball-containing clay 3E can be laminated on the entire outer surface of the article 42. . When using epoxy clay or the like which can maintain a three-dimensional shape with lead balls mixed therein as the lead ball-containing clay 3E, the lead ball-containing clay 3E is laminated on the outer surface of the article 42 by attaching, pasting, or the like.

Subsequently, the worker hardens the lead ball-containing clay 3E by drying or the like to form a layer of the lead ball-containing clay 3E on the entire outer surface of the article 42. The lead ball-containing clay 3E laminated on the article 42 in this manner includes clay and a plurality of solid lead balls mixed into the clay, and is hardened while covering the entire outer surface of the article 42. In this embodiment, the clay 3E containing lead balls shields the article 42 from radiation.

In this embodiment, as a radiation shielding member that covers the article 42, lead ball-containing clay 3E, which has good followability to the surface shape, is used. Therefore, the lead ball-containing clay 3E can be laminated in close contact with the entire surface of the article 42, and radiation can be shielded well.

(Seventh embodiment)
FIG. 10(A) is a sectional view of the radiation shielding member 8.
The radiation shielding member 8 can be transported and installed at a desired location. For example, by stacking them along the inner wall of a radiation equipment room, the radiation shielding member 8 can be used as a radiation shielding wall. Furthermore, the radiation shielding member 8 can be used to cover areas that cannot be covered by the radiation shielding wall or gaps in the radiation shielding wall.

The radiation shielding member 8 includes a lead ball-containing clay 3F that includes clay and a plurality of solid lead balls mixed with the clay, and a box-shaped member 43 that accommodates the lead ball-containing clay 3F inside. As the lead ball-containing clay 3F, for example, a slurry of liquid clay can be used. The box-shaped member 43 includes a box body 431 having an opening 4311 at the upper end, and a closing member 432 that closes the opening 4311.

In the radiation shielding method of this embodiment, the worker first mixes a plurality of lead balls with clay to produce lead ball-containing clay 3F, and as shown in FIG. Pour into the box body 431 through the opening 4311. Then, as shown in FIG. 10A, the worker can manufacture the radiation shielding member 8 that shields radiation by closing the opening 4311 with the closing member 432.

(Eighth embodiment)
FIG. 11 is a cross-sectional view for explaining the radiation shielding method.
The worker first mixes a plurality of lead balls into clay to generate lead ball-containing clay 3G. As the spherical clay 3G, for example, a slurry using liquid clay can be used.

Subsequently, the worker pours the lead ball-containing clay 3G into the formwork 44, and shields radiation with the lead ball-containing clay 3G. The formwork 44 can be installed, for example, on the inner wall of a radiation equipment room or on the outside of a nuclear reactor. The formwork 44 refers to a wall-like structure with a hollow interior. A radiation shielding structure 1G is configured including the lead ball-containing clay 3G and the formwork 44.

In this embodiment, the clay balls 3G are installed by pouring the slurry clay balls 3G into the formwork 44, so that the clay balls 3G can be thickly installed on the radiation shielding wall.

(Modified example)
The diameter of the lead balls 31, 31A may be smaller than 0.1 mm or larger than 0.5 mm, for example, 0.05 mm, 1 mm, 2 mm, or 5 mm. The diameters of the lead balls 31 do not have to be uniform to a predetermined value. The diameter of the lead ball 31A also does not have to be equal to a predetermined value.

As clay 32, 32A for clay containing lead balls 3, 3A to 3G, gypsum-based clay that hardens when mixed with water, calcium carbonate-based clay that hardens when dried, or polyester Polyester clay produced by mixing two agents, a resin prepolymer and a curing agent, may also be used. Depending on the size, location, and shape of the target area to be painted or laminated, whether to use a slurry-like clay that is easy to apply, or one that can be hardened while maintaining its shape as lead ball clay 3, 3A to 3G. All you have to do is decide. Furthermore, the hardness before solidification and the hardness after solidification of the lead ball-containing clays 3, 3A to 3G can be appropriately set depending on the material of the clays 32, 32A.

The clay containing lead balls 3, 3A to 3G may be provided on an appropriate radiation shielding wall such as lead plates 21, 22 in order to improve the radiation shielding ability. The clay containing lead balls 3, 3A to 3G may be provided outside the walls 11, 11B, 11C of the radiation equipment room.

3, 3A to 3G... Clay containing lead balls, 11, 11B, 11C... Wall portion, 21, 22... Lead plate (radiation shielding wall), 23... Gap, 31, 31A... Lead ball, 41... Housing, 42... Article, 43... Box-shaped member, 44... Formwork, 411... Curved surface portion, 431... Box body, 4311... Opening.

Claims (8)

Mix multiple lead balls (excluding boride-coated lead balls) with clay to produce clay with lead balls;
Attach lead plates adjacent to the indoor side of the wall of the room,
filling the gap between the adjacent lead plates with the lead ball-containing clay;
A method for constructing a radiation shielding structure in which the lead ball-containing clay is hardened and radiation is shielded in the gap by the lead ball-containing clay. 2. The method for constructing a radiation shielding structure according to claim 1, wherein the clay is a mixture of two components: an epoxy resin prepolymer and a curing agent. The method of constructing a radiation shielding structure according to claim 1 or 2, wherein the lead ball has a diameter of 0.1 to 0.5 mm. Mix multiple lead balls with liquid clay to create slurry-like clay containing lead balls.
Laminating the clay containing lead balls over the entire outer surface of the article by immersing the article in the clay containing lead balls and taking out the article from the clay containing lead balls ,
A radiation shielding method comprising curing the lead ball-containing clay and shielding the article from radiation by the lead ball-containing clay. Mix multiple lead balls with liquid clay to create slurry-like clay containing lead balls.
Pour the lead ball-containing clay into a mold having a stepped portion at the open end of the inner surface ,
A radiation shielding method in which radiation is shielded by the lead ball-containing clay inside the formwork provided on the inner wall side of a radiation equipment room . The radiation shielding method according to claim 4 or 5 , wherein the lead ball has a diameter of 0.1 to 0.5 mm. Lead plates attached to the indoor side of the wall of the room, adjacent to each other with gaps between them ;
a lead ball-filled clay that includes clay and a plurality of solid lead balls (excluding boride-coated lead balls) mixed into the clay, filling the gap and shielding radiation in the gap;
A radiation shielding structure equipped with. A lead ball-containing clay comprising clay and a plurality of solid lead balls mixed in the clay, which is hardened to cover the entire outer surface of the article with an even thickness , and shields radiation to the article.