JP2896538B2 - Construction method of radiation shielding wall - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of constructing a radiation shielding wall constructed around various radiation generating devices.

[0002]

2. Description of the Related Art Radiation shielding measures are important in facilities that store radiation generators such as particle accelerators that generate radiation (bremsstrahlung, neutrons, etc.). As a conventional means for shielding radiation, a method has been known in which a concrete-based wall is integrally formed around the radiation generating apparatus and a facility building (ceiling or floor) around the radiation generating apparatus. I have.

[0003]

The above conventional radiation shielding technique has the following problems. <B> When updating or modifying the radiation generator,
Shielding walls must be removed. The wall can be removed by hanging or cutting, but it requires a lot of time and effort. Moreover, dust, noise, vibration, etc. are generated during construction. <B> After removing the wall, it is necessary to reconstruct a new shielding wall, which poses a problem in terms of construction economics.

[0004]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide the following method of constructing a radiation shielding wall. <A> Construction method of radiation shielding wall with excellent workability. <B> A method of constructing a radiation shielding wall that allows the shielding wall to be partially detached. <C> A method of constructing a radiation shielding wall that improves the radiation shielding effect. <D> A method of constructing a radiation shielding wall that is easy to remove.

[0005]

According to the present invention, there is provided a method for constructing a radiation shielding wall around a radiation generating apparatus, comprising dividing the shielding wall into a plurality of blocks and shielding a steel frame presenting the outer shape of the block. This is a method for constructing a shielding wall, comprising arranging along a line for constructing a wall, casting concrete in each steel frame, and constructing the shielding wall on site.

[0006]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

<A> Storage Facility FIG. 1 shows a plan view of a radiation generator (for example, a storage facility for storing a synchrotron), and FIG. 2 shows a central sectional view thereof. The containment facility has a floor 1 on which the radiation generator is installed,
The facility is a Brehab-type facility that includes a polygonal shielding wall 2 and a ceiling 3 that closes off the upper opening of the shielding wall 2.

<B> Shielding Wall FIG. 3 is a perspective view in which an upper portion of the shielding wall 2 is omitted. The shielding wall 2 is composed of an aggregate of a plurality of blocks 21. Each block 21 is composed of a steel frame 22 and concrete 23 cast in the steel frame 22. The steel frame 22 has both a function as a mold and a function of shielding radiation, and for example, an iron plate or the like can be used as a material thereof. In addition, when the blocks 21 are simply formed and arranged in a rectangular cross section, there is a danger that radiation will leak from the joint. Therefore, in the present invention, each block 2
The following improvements were made to prevent radiation from leaking from the junction between the two. That is, each block 2
A pair of end faces 25, 25 sandwiched between the two side faces 24, 24
A step surface 26 in a direction intersecting with the end surface 25 was formed on the way. FIG. 1 shows an example of allocation of shielding walls and a combination example of the end face 25 of each block 21. In short, it is only necessary that the end faces 25 of the respective blocks 21 be formed in a shape that does not leave a gap at the joint when the end faces 25 are joined. Therefore, the end face 25 may employ a combination of arcuate curved surfaces.

[0009]

Next, the construction method of the storage facility will be described.

<A> Installation of steel frame A support 4 is erected at the corners and the center of the shielding wall 2 to be constructed. The support 4 uses a steel pipe or the like. Next, a truss structure beam 5 is erected between the upper portions of the columns. The column 4 erected on the floor 1 and the beam 5 erected on the column 4 are fixed using bolts or the like so as to be dismantled. Then, the steel frames 22 are sequentially arranged along the planned installation position of the shielding wall 2. At this time, each steel frame 2
The two end faces 25 are fitted so that there is no gap. The steel frame 22 that comes into contact with the support 4 needs to have its end face 25 curved in accordance with the curved surface of the support 4.

<B> Completion of Shielding Wall Next, concrete 23 is cast into each steel frame 22 to form a heavy block 21 and the final shielding wall 2 is obtained. The upper end of each block 21 is fixed to the beam 5 to prevent the shielding wall 2 from falling. The joint portion of each block 21 has almost no gap over its entire length, and furthermore, the fitting end surfaces 25, 2
Since 5 forms a non-linear surface via the step surfaces 26, 26, it is possible to effectively prevent radiation from leaking at the joint. In particular, the concrete pressure cast on the site
Therefore, even if slight gaps are generated before the concrete is cast, these gaps can be eliminated and the end faces 25 of the blocks 21 can be brought into close contact. When the beam duct of the radiation generator is arranged so as to penetrate the inside and outside of the shielding wall 2, a large opening is provided in advance in the block 21 of the portion to be penetrated, and after the beam duct is penetrated through the opening of the block 21. Fill the opening with concrete to deal with it. Note that a door slidable in the penetrating direction of the shielding wall 2 is provided on a part of the shielding wall 2 shown in FIG.

<C> Placement of Ceiling When the construction of the shielding wall 2 is completed, the ceiling 3 is placed on the upper opening of the shielding wall 2 to form a space having a sealed structure. FIG. 4 shows an example of the layout of the ceiling 3. The ceiling 3 is made up of an aggregate of square blocks 31. Each block 31 is made of a steel frame having a bottomed structure and concrete cast at the site like the block 21. In order to prevent radiation leakage, the ceiling 3 is made up of a plurality of laminated structures as shown by the solid line and the broken line in FIG. 4, and the joining positions of the blocks 31 constituting the upper and lower ceilings 3 overlap on the same perpendicular. The position is shifted so that it does not become. The weight of the ceiling 3 is supported by the shielding wall 2 and the column 4 via the beam 5. In addition, the shielding wall 2 and the ceiling 3 are blocks 21 and 31
Therefore, the joint between the blocks 21 and 31 is subjected to a silicone resin caulking,
If oil paint is applied to the surfaces of 1, 31, the airtightness in the facility is further improved.

<D> Partial Removal of Shielding Wall When removing a part of the shielding wall 2 due to the necessity of updating or modifying the radiation generator, the following procedure is taken. First, after removing the upper portion of the block 21 at the position to be removed from the beam 5, it is sufficient to simply pull out the block 21 outward or inward as shown in FIG. 3. The block 21 is moved by pressing with a jack or the like or by pulling. When the updating work is completed, the block 21 is returned to the original position and the shielding wall 2
To restore.

<E> Dismantling of the entire facility When dismantling the entire facility, the ceiling 3 is lifted and removed, and then the block 21 constituting the shielding wall 2 is lifted or moved horizontally to remove. Finally, if the bolts 4 and beams 5 that have been bolted are removed, the entire facility is completely dismantled.

[0015]

[Other Embodiments] If the beam 5 and the ceiling 3 are directly supported by the shielding wall 2, the support 4 can be omitted.

[0016]

The present invention has been described above, and the following effects can be obtained. <A> Since the shielding wall is composed of a plurality of blocks, it is possible to partially remove the shielding wall by extracting a block at an arbitrary position. Therefore, it is possible to easily update or modify the radiation generator. In addition, the present invention makes it possible to remove the shielding wall easily and without generating vibrations and dust, as compared with the conventional technique of removing the shielding wall by hanging or cutting. <B> Since the shielding wall is formed of a laminated structure of a steel frame and concrete, which hardly transmits radiation, the radiation transmission preventing effect is improved. <C> Since the blocks are joined via the non-linear surface, it is possible to effectively prevent the leakage of radiation at the joint of the blocks. <D> By casting concrete on site, the joints of each block are pressurized and help to eliminate gaps. <E> Compared with the method of transporting heavy existing blocks to the site and assembling them, the number of steps and work time required for transporting and installing the blocks can be greatly reduced. <F> The construction period can be significantly reduced.

[Brief description of the drawings]

FIG. 1 is a plan view of a shielding wall.

FIG. 2 is a sectional view taken along the line II-II in FIG.

FIG. 3 is a perspective view of a block constituting a shielding wall.

FIG. 4 is a plan view of a ceiling.

──────────────────────────────────────────────────続 き Continuing on the front page (72) Hirofumi Kamada, Inventor 1-25-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo Inside Taisei Corporation (72) Inventor Masahiro Taniguchi 1-25-1, Nishi-Shinjuku, Shinjuku-ku, Tokyo No. Taisei Corporation (72) Inventor Shunji Harada 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsubishi Electric Corporation (56) References JP-A-57-24752 (JP, A) JP-A-58 JP-A-106495 (JP, A) JP-A-61-91599 (JP, A) JP-A-61-277095 (JP, A) JP-A-1-189597 (JP, A) (Japanese) Shokai 61-146796 (JP, U) JP-A 1-1117598 (JP, U) (58) Fields investigated (Int. Cl. ⁶ , DB name) G12B 17/00 G21F 3/04

Claims (2)

(57) [Claims] 1. A method of constructing a radiation shielding wall around a radiation generating device, comprising: dividing the shielding wall into a plurality of blocks; and arranging a steel frame having an outer shape of the block along a construction line of the shielding wall. A method of constructing a radiation shielding wall, comprising constructing a shielding wall on site by placing concrete in each steel frame. 2. The steel frame according to claim 1, wherein each end face of the steel frames to be joined to each other is formed in a corresponding non-linear surface, and the end faces of the steel frames are fitted without any gap. Construction method of radiation shielding wall.