JP3495887B2 - Cylindrical split type adiabatic radiation shielding device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement of a cylindrical split type adiabatic radiation shielding device suitable for use in piping, equipment, containers, etc. of a nuclear power plant.

[0002]

2. Description of the Related Art Nuclear power plants are legally obliged to carry out inspections during service, so the heat insulation equipment attached to the piping of the plant must be exposed to radiation dose during maintenance and inspection work under radiation. In order to minimize it, a cylindrical split type heat insulating device that is easy to put on and take off is adopted.

In the cylindrical split type heat insulating device, a hollow cylindrical body is vertically divided in half so that a pipe can be held therein. Aluminum foil that has been processed and wrinkled
There is known a structure in which heat insulating materials such as stainless steel foil are filled and arranged in a laminated manner.

[0004]

Recently, in a nuclear power plant, in order to ensure the safety of workers and improve the working environment, a lead plate shielding material for shielding radiation such as gamma rays is used in the metal box body. Cylinder split type heat insulation device incorporated in is often used.

A conventional heat insulation device incorporating a shielding material uses an end plate made of stainless steel, installs the shielding material in the innermost layer of the cylindrical split type box body, and attaches only the outside of the shielding material with a holding metal fitting, or heat insulation. In the case of supporting in the middle of the layers, there is known a structure in which a clamp member is welded to a stainless steel end face plate and the shield plate is clamped by the clamp member.

Further, in order to improve the radiation shielding performance, the thickness of the shielding material tends to be thicker than the conventional one. However, since the shielding material is a heavy metal, the weight increases, so the number of cylinder divisions must be increased in consideration of handleability, but if the number of divisions increases, the cylindrical division type metal box is formed. The heat loss from the end plates (plates located at both ends of the cylindrical box body in the circumferential direction and the axial direction) increases, and the heat insulating performance deteriorates.

As a measure for suppressing the heat loss in the end plate, there is a method of using a low heat conductive steel plate such as a stainless steel fiber sintered plate or a metal foam plate for the end plate. However, since the low thermal conductive steel sheet has a porous structure, there is a problem that the weldability is poor and the shielding material which is a heavy metal cannot be firmly supported.

It is a main object of the present invention to provide a cylindrical split type adiabatic radiation shielding device in which a shielding material can be detachably incorporated in a short time without deteriorating the heat insulation performance and the radiation shielding performance.

[0009]

According to the present invention, there is provided a cylindrical split type metal box body comprising an inner face plate, an outer face plate, end face plates located at both ends in the circumferential direction, and end face plates located at both ends in the axial direction. The end plate is formed of a low heat conductive steel plate having a porous structure, a heat insulating material is filled and arranged in the box body, and a semicircular arc-shaped radiation shielding material is provided at an intermediate portion of the filling layer of the heat insulating material. A cylindrical split type adiabatic radiation shielding device configured as follows, wherein the arc-shaped radiation shielding material is in contact with an end face plate in the circumferential direction of the box and an end in contact with the end face plate in the axial direction of the box. The gist is that the portion is configured to be sandwiched by sandwiching metal fittings respectively coupled to the inner surface plate and the outer surface plate.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION As a preferred embodiment of the present invention, as shown in FIGS.
Is formed of an arc-shaped inner face plate a ₁ , an outer face plate a ₂ , end face plates a ₃ and a ₃ located at both ends in the circumferential direction, and end face plates a ₄ and a ₄ located at both ends in the axial direction, A heat insulating material made of rock wool, glass wool, or a thin metal plate 2 is filled and arranged in the inside thereof, and a semicircular arc-shaped lead shielding material B is disposed in the lamination, and the shielding material B is an end face plate a. _The end portion that abuts ₃ has two L-shaped metal fittings C ₁ and C ₃ and L-shaped clamp metal fittings C ₂ and C _4.
It is configured to be sandwiched on the side of the box body through a connecting metal fitting consisting of and, and the end portion where the shielding material B contacts the end face plate a ₄ is 2
The L-shaped metal fittings C ₅ and C ₇ and the two L-shaped clamping metal fittings C ₆ and C ₈ are clamped to the box side via a coupling metal fitting.

[0011]

1 to 6 show an embodiment of the present invention. 1 to 6, A is a semi-cylindrical metal box body obtained by vertically dividing a hollow cylinder into halves, and has an arc-shaped inner surface plate a ₁ , an arc-shaped outer surface plate a ₂ , and both ends in the circumferential direction. End face plate a ₃ , located at
a ₃ and end face plates a ₄ and a ₄ located at both ends in the axial direction
The inner surface plate a ₁ and the outer surface plate a ₂ are made of stainless steel, and the end surface plates a ₃ and a ₄ are made of a porous low heat conductive steel plate obtained by sintering stainless steel fiber under high temperature vacuum. There is.

[0012] B is to be located in a semi-tubular box body intermediate a lead made of shielding material which is bent in a semicircular arc shape with a predetermined radius of curvature, as shown in FIG. 2, end plates a ₃ , A ₃
The end portion abutted on is held in the box body by the following means via a connecting metal fitting composed of two L-shaped metal fittings C ₁ and C ₃ and two L-shaped holding metal fittings C ₂ and C ₄ . .

The procedure for assembling the shield on the box side is as follows.
First, the inner surface plate a ₁ and the end surface plate a ₃ are connected to each other by spot welding using the L-shaped metal fitting C ₁ as a connecting material. After that, the L-shaped holding metal fitting C ₂ is connected to the L-shaped metal fitting C ₁ by spot welding. On the other hand, to couple the L-shaped fitting C ₃ serving as a connecting member to the end plate a ₃ by spot welding.

Next, after a heat insulating material consisting of the specially shaped metal plates 2 shown in FIGS. 4 to 6 is stacked and arranged on the inner surface plate a ₁ , the semi-circular shielding material B is sandwiched between the L-shaped members. Metal fitting C ₂
Is temporarily placed in contact with the L, and the outer side of the shielding material B is sandwiched by the L-shaped clamping metal fittings C ₄ so that it is attached in advance.
It is connected to the metal mold C ₃ by spot welding. After that, the heat insulating material made of the metal plate 2 is further packed and arranged on the outer surface of the shielding material B, and the outer surface plate a ₂ is superposed on the front side thereof, and L
It is connected to the metal mold C ₃ with a rivet (not shown).

On the other hand, as shown in FIG. 3, the end portion where the axial end surface of the semi-circular shielding material B abuts the end face plate a ₄ also has two L-shaped fittings C ₅ , C ₇ and two L-shaped fittings. Clamps C ₆ , C ₈
It is held in the box body by means similar to the above, via the connecting metal fitting consisting of.

That is, the inner plate a ₁ and the end plate a ₄ are connected to each other by an L-shaped metal fitting C.
_{Using 5} as a connecting material, they are connected to each other by spot welding, and then the L-shaped clamping metal fitting C ₆ is connected to the L-shaped metal fitting C ₅ by spot welding. On the other hand, an L-shaped metal fitting C ₇ which serves as a connecting member for the outer surface plate a ₂ is joined to the end surface plate a ₄ by spot welding.

Next, after the heat insulating material composed of the metal plate 2 is filled and arranged in a laminated form, the semi-arcuate shielding material B is temporarily placed in contact with the L-shaped holding metal fitting C ₆ , and the shielding material B is placed.
The outer side of the above is sandwiched by the L-shaped holding metal fittings C ₈ and is joined by spot welding to the L-shaped metal fittings C ₇ previously attached. After that, the heat insulating material composed of the metal plate 2 is further packed and arranged on the outer surface of the shielding material B, and the outer surface plate a is provided on the front side thereof.
₂ are piled up and connected to the L-shaped metal fitting C ₇ with a rivet (not shown).

Thus, according to the above construction, the heavy metal semi-arcuate shielding material housed in the cylindrical split type box body has a porous structure located at both ends in the circumferential direction and the axial direction of the box body. It is stably held on a low heat conductive steel plate by means not involving welding. In this case, when the shield plate is clamped, the L-shaped clamps C ₂ , C ₄ and the L-shaped clamps C ₆ , C ₈ can be adjusted in their mounting positions according to the size of the shield.

The metal thin plate 2 used as a heat insulating material, which is filled and arranged in a laminated manner in the box A constituting the cylindrical split type adiabatic radiation shielding device, reflects radiant heat on its surface and also between the metal thin plates. The formed air layer serves as a heat insulating layer that exerts a heat insulating effect, and has a thickness of 0.05 mm.
A stainless plate or an aluminum plate with a thickness of 0.1 mm is used.

On the thin metal plate 2, V-shaped ribs 2a and 2b, which are embossed in a lattice pattern at required intervals, and the ribs 2 are formed.
A conical projection 2c, which is stamped higher than the ribs, is provided at the center of the lattice plane portion partitioned by a and 2b. The V-shaped ribs 2a and 2b embossed on the metal thin plate 2 in a lattice shape are important factors for bending and holding the metal thin plate 2 in a polygonal shape concentric with the semi-cylindrical box body. That is, when the thin metal plates are packed in a semi-cylindrical box body in a laminated form, the ribs 2a in the axial direction of the box body are easily bent, the ribs 2b in the circumferential direction resist the bending, and in the middle of the ribs in the axial direction. Since it is difficult to bend, the thin metal plate can be easily bent and held in a polygonal shape concentric with the semi-cylindrical box body. The distance between the V-shaped ribs 2a and 2b provided on the metal thin plate 2 in a grid pattern is 10 to 70.
The height of the V-shaped rib is about 1 mm, which is suitable for piping.

The conical projections 2c serve to hold the thin metal plates at regular intervals, and it is preferable that the conical bottom surface has a diameter of 10 to 15 mm and a height of 3 to 8 mm for heat insulation performance. It is desirable to reduce the number of the conical protrusions 2c as much as possible from the viewpoint of heat insulation performance. Therefore, the distance between the conical protrusions is 50 to 70 m.
m is suitable.

Further, it is preferable that the conical protrusions 2c are provided at different phase portions between the laminated metal thin plates. For example, as shown in FIG. 4, when a metal thin plate is used in which the pitch of the protrusions 2c provided on the lattice plane portion defined by the V-shaped ribs 2a and 2b is different in the orthogonal direction, the metal thin plate is The protrusions of adjacent metal thin plates can be set to different phases simply by rotating them by 90 degrees and sequentially laminating them, or by sequentially laminating them by shifting the pitch of the protrusions by 1/2 in the axial direction of the semi-cylindrical box. Can be done easily.
The embodiment of FIG. 6 shows a state in which thin metal plates are laminated by the latter means.

With the above-described structure, the strength of the metal thin plate itself is improved, deformation such as warping due to the influence of heat is eliminated, and heat conduction due to contact between the metal thin plates is minimized and the surface of the metal thin plate is minimized. The effect of reflecting the radiant heat is effectively exerted, and an excellent heat insulating effect is exhibited.

[0024]

As described above in detail, according to the present invention, a cylindrical split type heat insulating radiation shield device in which a shield member can be detachably incorporated in a short time without deteriorating heat insulation performance and radiation performance. Is obtained.

[Brief description of drawings]

FIG. 1 is a perspective view of a cylindrical split type adiabatic radiation shielding device showing an embodiment of the present invention.

FIG. 2 is an enlarged sectional view taken along line XX of FIG.

3 is a cross-sectional view taken along line YY of FIG.

FIG. 4 is a plan view of a thin metal plate.

FIG. 5 is a side surface of a thin metal plate.

FIG. 6 is a cross-sectional view of laminated metal sheets.

[Explanation of symbols]

A Semi-cylindrical metal box a ₁ Inner plate a ₂ Outer plates a ₃ , a ₄ End plate B Radiation shields C ₁ , C ₃ , C ₅ , C ₇ L-shaped metal fittings C ₂ , C _{4 with} angle cross section , C ₆ and C ₈ angled L-shaped clamps 2 Metal thin plates 2a and 2b V-shaped ribs 2c Conical protrusions

Claims (3)

(57) [Claims] 1. A cylindrical split type metal box body is formed by an inner face plate, an outer face plate, end face plates located at both ends in the circumferential direction, and end face plates located at both ends in the axial direction. Is a low heat conductive steel plate having a porous structure, a heat insulating material is filled and arranged in the box body, and a semicircular arc-shaped radiation shielding material is provided at an intermediate portion of the filling layer of the heat insulating material. The arc-shaped radiation shielding material has an end portion abutting on the end face plate in the circumferential direction of the box body and an end portion abutting on the end face plate in the axial direction of the box body for the inner face plate and the outer face plate, respectively. A cylindrical split type adiabatic radiation shielding device, which is configured to be sandwiched by coupled sandwiching metal fittings. 2. An inner face plate and an end face plate are connected by spot welding through a first L-shaped metal fitting, a second L-shaped clamping metal fitting is connected by spot welding to the first L-shaped metal fitting, and a third L-shaped metal fitting is separately attached to the end face plate. Is connected by spot welding, and the second L-type clamping metal fitting and the third L-shaped metal fitting are connected by spot welding to the fourth L
The cylinder-divided adiabatic radiation shielding device according to claim 1, wherein the radiation shielding material is sandwiched between the die sandwiching metal fitting. 3. The heat insulating material is provided with ribs embossed on a metal thin plate in a grid pattern, and projections that are embossed higher than the ribs on a surface portion defined by the grid ribs. The cylindrical split type adiabatic radiation shielding device according to claim 1, which is constructed.