JPH02302697A - Construction of shielding wall - Google Patents

Abstract

PURPOSE:To enhance a shielding effect of a radiation and to reduce a thickness of a shielding wall by kneading lead particles coated with a cladding material, such as a resin, on their surface parts, with a concrete material, and by placing the concrete kneaded with the lead particles. CONSTITUTION:Surfaces of lead particles 2 or 0.5 to 0.3mm diameter, for instance, which are spherically formed, are coated with a synthetic resin cladding material 3 consisting of a high molecular compound such as a Teflon or a polyethylene and so on. Then, the coated lead particles 2 are kneaded with a concrete material 4, are cast into a formwork through a hose and, after setting, the formwork is removed to complete a shielding wall 1 in which the lead particles 2 are scattered at almost equal distance each other. With this process, the wall thickness can be reduced as far as an extent to be able to be saved by an effect by mixing the lead particles 2 into the concrete, and, as the lead particles 2 are insulated from a water content of the concrete material 4, a corrosion of the particles is prevented and a highly shielding effect can be maintained.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method of constructing a shielding wall that shields radiation emitted from a nuclear reactor pressure vessel, etc., and particularly relates to a method of constructing a shielding wall that shields radiation from a nuclear reactor pressure vessel. This article concerns how to construct a shielding wall.

[Prior Art] In facilities such as nuclear power plants, a shielding wall is erected around the nuclear pressure vessel in order to shield radiation emitted from the nuclear pressure vessel, which serves as a radiation source. Generally, shielding walls are constructed by pouring an inexpensive concrete material.

[Problems to be Solved by the Invention] By the way, the main purpose of shielding radiation is gamma rays, and in order to attenuate these gamma rays, a shielding wall with a large specific gravity is required.

Therefore, in the past, the thickness of the concrete walls constituting the shielding walls was increased depending on the intensity of the radiation, or heavy concrete walls were used in which iron and steel stone was mixed as aggregate into the concrete. As a result, there was a problem in that the effective space within the building became smaller.

Furthermore, lead material is generally known as a shielding material, and this lead material is easily available. Therefore, there are methods of pasting lead sheets along concrete walls or stacking lead blocks, but the pasting is work and the stacking work is sIa.
and requires effort. It is also conceivable to add lead material into the concrete wall. In this case, the lead material is corroded by moisture in the concrete and alkaline components dissolved from the aggregate, creating cavities in the lead material, resulting in a problem that a sufficient shielding effect cannot be obtained.

The present invention has been made in consideration of the above circumstances.

The present invention provides a method for constructing a shielding wall for shielding radiation, comprising:
It is an object of the present invention to provide a method for constructing a shielding wall that can make the shielding wall thinner, expand the effective space of a building, and save labor.

[Means for Solving the Problems] The present invention provides a method for constructing a shielding wall for shielding radiation emitted from a nuclear pressure vessel or the like, in which the surface of lead granules is coated with a coating material such as a resin in advance, and then the coating is applied. It is made by mixing lead granules with concrete material and pouring it.

[Function] In this way, since the lead particles are mixed into the shielding wall, the shielding effect is enhanced by the amount of lead particles mixed in, and the shielding wall can be made thinner. In addition, since the lead granules are coated with a coating material, the lead granules are insulated from the concrete material.
Can prevent corrosion of lead particles.

[Example] An embodiment of the present invention will be described in detail below with reference to the accompanying drawings.

1, 2 and 3 show a first embodiment of the present invention.

This embodiment shows a shielding wall 1 that partitions the dose area of a building.

First, when constructing the shielding wall 1, as shown in FIG. 2, spherical lead particles 2 are formed. The lead particles 2 have a particle size of, for example, 0.511 nφ to 0.3+11φ, and the surface thereof is coated with a coating material 3 made of a synthetic resin made of a polymeric material such as Teflon or polyethylene.

Specifically, the coating material 3 is formed to have a thickness of 5 μm in one treatment.

As shown in FIG. 3, the lead granules 2 coated with the coating material 3 are mixed with the concrete material 4 and introduced into the formwork 6 via the supply hose 5.

After the concrete material 4 has solidified, the formwork 6 is removed,
As shown in FIG. 1, a shielding wall 1 having lead particles 2 scattered at approximately equal intervals is completed.

Therefore, the shielding wall 1 can be made thinner by the amount of lead particles 2 mixed therein. Moreover, since the surface portion of the lead granules 2 is coated with the coating material 3, the lead granules 2 are insulated from the moisture of the concrete material 4, and corrosion of the lead granules 2 can be prevented.

Since the lead particles 2 serve as a substitute for aggregate, the lead particles 2 are configured to contain molybdenum (maximum 6%) in order to increase mechanical strength.

Next, FIG. 4 to FIG. 1O show a second embodiment of the present invention, in which a shielding wall 12 is constructed at a position relatively close to a radiation source such as a nuclear pressure vessel 11. It is.

As shown in FIG. 4, this shielding wall 12 is erected on the same foundation 13 as the reactor pressure vessel 11.

Further, the central portion of the shielding wall 12 is composed of an inner shielding wall 12a covered with a steel formwork 14, and an outer shielding wall 12b covering the inner shielding wall 12a.

Specifically, the formwork 14 is installed rising upward from an embedded metal fitting 15 provided in the foundation 13, and the embedded metal fitting 15 has a plurality of legs 16 that are inserted into the foundation 13, and each leg has a plurality of legs 16. A flat plate part 17 laid along the surface of the foundation 13 is joined to the base 16.

In addition, the formwork 14 is provided with an inner wall 18 and an outer wall 19 which are spaced parallel to each other on the embedded hardware 15, and the inner and outer walls 18 and 19 are arranged in cross-sections upward so as to face each other. The bent stiffeners 20 are provided at regular intervals in the vertical direction. This stiffener 20 is formed with a gap prevention hole 21 passing through it in the vertical direction. Also,
A lid 22 is joined to the upper portions of these inner and outer walls 18 and 19.

Further, as in the above embodiment, lead granules 2 whose surfaces are coated with a coating material 3 such as resin are formed in advance on the formwork 14, and the lead granules 2 are kneaded with concrete material 4 and cast. will be established.

Further, a concrete wall layer 23 is poured to cover the outer side of the formwork 14 to form an outer shielding wall 12b. Therefore, the concrete wall layer 23 is formed via the formwork 14 so as to cover the inner shielding wall 12a.

Therefore, in constructing such a shielding wall 12 horizontally, first, as shown in FIG. 5, embedded metal fittings 15 are formed in the foundation 13. For this embedded metal fitting 15, after the leg portion 16 is inserted into the foundation 13, a flat plate portion 17 is joined thereto along the surface portion of the foundation 13.

Next, as shown in FIG. 6, a steel formwork 14 is erected on the embedded metal fitting 15. In this case, the inner wall 18 and the outer wall 19 are welded to each other and spaced apart from each other on the flat plate part 17, and these inner and outer walls 18, 19
The stiffeners 20 are attached at equal intervals in the vertical direction so as to face each other. 31 is a welding part.

Therefore, a hollow chamber 32 for forming the inner shielding wall 12a is formed between the inner wall t18 and the outer wall 19.

Next, after the inner and outer walls 18 and 19 are raised and installed on the foundation 13, the lead particles 2 mixed with the concrete material 4 are poured into the hollow chamber 32 formed between the inner and outer walls 18 and 19. In other words, as shown in Figure 7, inside and outside! ! An input port 33 is formed in the upper part of 18.19, and a supply hose 34 for supplying concrete material 4 containing lead granules 2 from above is directed to this input port 33, and a supply hose 34 is directed between the inner and outer walls 18.19. Concrete material 4 containing lead particles 2 is continuously supplied.

When the concrete material 4 containing the lead particles 2 is continuously supplied in this way, as shown in FIG.
In between, the lead granules 2 and the concrete material 4 are sufficiently cast from the bottom to the input port 33. Therefore, when the concrete material 4 solidifies, the inner shielding wall 12a will be formed.

When the lead granules 2 and the concrete material 4 are introduced, void prevention holes 21 are formed in the stiffener 20 in advance, so that when the stiffener 20 is installed, voids are formed around the periphery. , and the lead particles 2 and concrete material 4 can be sufficiently filled. Further, since the stiffener 20 is embedded within the inner shielding wall 12a, the mechanical strength of the inner shielding wall 12a is also increased.

Next, as shown in FIG.
will be blocked.

Therefore, the inner shielding wall 12a is covered with a steel surrounding wall made of the formwork 14.

After the inner shielding wall 12a and the surrounding wall made of the steel formwork 14 are formed to cover it, as shown in FIG. A concrete wall layer 23 is formed by pouring.

By covering the outside of the formwork 14 with this concrete wall layer 23, the outer shielding wall 12b is formed, and the shielding g112
reaches completion.

In the second embodiment, the concrete material 4 containing the lead granules 2 is poured into the formwork 14, but the structure is not limited to this. In addition, only the lead granules 2 may be poured into the formwork 14. It may also be filled.

In this case, when the lead filling rate is 1, the thickness of the shielding wall 12 can be reduced by the ratio of the specific gravity of the concrete material to the specific gravity of lead. Therefore, when the lead filling rate is 0.5, the shielding effect becomes 1/2. That is, when the filling factor is set to 1, the wall thickness that is reduced by 172 is the actual wall thickness that can be reduced.

Furthermore, the lead particles 2 will be oxidized due to the voids formed within the formwork 14. When oxidized in this way, powder bulges out on the surface of the lead granules 2 and falls off, reducing the particle size.In the present invention, the lead granules 2 are coated with the coating material 3 in advance. This also means that deterioration (oxidation) of the lead particles 2 can be prevented.

Furthermore, since the lead particles #2 are coated with the coating material 3, even if the lead particles 2 collide with each other when the lead particles 2 are introduced into the formwork 14, the impact is absorbed by the coating material 3. de1
You can lnll. Therefore, generation of dust can be prevented, and measures such as local exhaust ventilation are not required.

Moreover, when the lead particles 2 are placed into the formwork 14, there is a risk that they may be deformed by the impact of falling. Therefore, it is effective to add molybdenum or antimony to the lead particles 2 for reinforcement. For example, in the case of antimony, it is an alloy mixed with lead in a range of up to 6 ounces.

In this way, in the present invention, the shielding wall 1.12 is constructed by kneading the lead particles 2 with the concrete material 4, so the shielding effect is increased by the amount of lead particles 2 mixed into the shielding wall 1.12. , the thickness of the shielding walls 1, 12 can be reduced. Therefore, the effective space within the building divided by the shielding wall 1.12 can be expanded. In addition, since the surface of lead grain #2 is coated with coating material 3, lead grain #2
are insulated from the concrete material 4, corrosion of the lead particles 2 can be prevented, and a high shielding effect can be maintained.

Furthermore, since the lead granules 2 and the concrete material 4 are fluidized, they can be easily transported and the work effort can be reduced.

[Effects of the Invention] In summary, according to the present invention, the following excellent effects are achieved.

(1) Since the shielding wall is formed by kneading lead particles with concrete material, the thickness of the shielding wall can be reduced and the effective space can be expanded.

(2) Since the lead particles are coated with a coating material, corrosion of the lead particles can be prevented and a high shielding effect can be maintained.

(3) Since lead particles and concrete materials can be easily transferred, work effort can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a plan sectional view showing a shielding wall according to a first embodiment of the present invention;
Figure 2 is a sectional view showing lead granules, Figure 3 is a diagram showing the state of lead granules and concrete material, Figure 4 is a sectional view showing a nuclear facility, and Figure 5 is a sectional view showing embedded metal fittings. , 6th
The figure is a cross-sectional view showing the stage of installing the formwork, Figure 7 is a cross-sectional view showing the charging state of lead granules and concrete material, Figure 8 is a cross-sectional view showing the filling state of lead grains and concrete material, and Figure 9 The figure is a sectional view showing the state in which the inner shielding wall is formed.
Figure 0 is a sectional view of the completed shielding wall. In the figure, 1 and 12 are shielding walls, 2 is lead particles, 3 is coating material, and 4
is concrete material. Patent applicant Ishikawajima Ban! 1 Heavy Industries Co., Ltd. Representative Patent Attorney Nobuo Kinutani (1 other person) 13.) Figure 4 Figure 5 Figure 1 ○

Claims (1)

[Claims] 1. In a method for constructing a shielding wall to shield radiation emitted from nuclear pressure vessels, etc., the surface of lead particles is coated with a coating material such as resin in advance, and then the coated lead particles are kneaded with concrete material. A method for constructing a shielding wall, characterized in that it is constructed by pouring.