JP2010045891A - Cable duct for radiation generating apparatuses - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cable duct for radiation generating apparatus which can satisfy each of three characteristics, i.e. withstand voltage, high hermeticity and fire protection area, being requested when the cable duct is used in a radiation generating apparatus such as an accelerator. <P>SOLUTION: A cable duct for radiation generating apparatus has a double coaxial structure of tubular internal metal piping 11 and an outer duct 13 of square cross-section, wherein airtight treatment and withstand voltage treatment are performed by means of an airtight treatment board 17 and an airtight gasket at an airtight treatment section A, and fire protection area treatment and withstand voltage treatment are performed by means of a fire protection treatment board 19 and a coating of fire protection material at a fire protection area treatment section B. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a cable duct for a radiation generator capable of satisfying all of the three characteristics required for use in a radiation generator such as an accelerator, withstand voltage, high airtightness, and fire-proofing property. .

  In large-scale facilities such as factories and power plants, laying paths such as cable ducts are installed vertically and horizontally in the facilities, and many electrical cables, insulated wires, cords, etc. are laid in close contact with each other. (For example, see Patent Document 1).

  However, a cable duct used in a general electric facility cannot satisfy voltage resistance, high airtightness, and fireproof compartment at the same time. For example, a fire prevention section is usually formed in a general electric facility, but the withstand voltage required for an accelerator or the like is not taken into consideration.

On the other hand, gaskets are generally used in places where high airtightness is required, but voltage resistance is not generally considered in fields where airtight gaskets are used.
JP 2002-5982 A

  However, in an accelerator facility that accelerates high-intensity protons, the accelerator tunnel becomes a high-dose radiation field. Since there is no fire extinguishing equipment that can be used in such a place, the cable duct that penetrates the room needs to have a fireproofing property. Further, in order to prevent the highly activated air from leaking outside the tunnel, it is essential for the cable duct to have high airtightness. Furthermore, since an accelerator or the like can be applied up to a DC voltage of about 70 kV, a withstand voltage is required up to this voltage.

  The present invention has been made in view of the above problems, and the object of the present invention is to provide any of the three characteristics of voltage resistance, high airtightness, and fireproofing properties required when used in a radiation generator such as an accelerator. It is another object of the present invention to provide a cable duct for a radiation generator that can satisfy the above requirements.

  The cable duct for a radiation generator according to the present invention is a cable duct for a radiation generator that has a shield wall penetrating at least one side thereof and is connected to the activated air generating area. The cable is laid in the internal pipe and the same voltage as the cable is applied to the external duct, and the external duct is set to the ground potential. A glass FRP hermetic treatment plate is provided between the internal pipe and the external duct, and silicon is formed in the gap between the gas tight treatment plate and the internal pipe and the gap between the air tight treatment plate and the external duct. A rubber gasket is provided, and a two-pack type silicone rubber is placed on the calcium silicate plate between the internal pipe and the external duct in the fire prevention compartment processing section. Provided with a fire protection plate having computing, the gap between the inner pipe and the fire protection plates, characterized in that a fire protection material coating of two-liquid type silicone rubber.

  When the applied voltage is 70 kV, the thickness of the fireproof material coating is preferably 18.4 mm or more.

  It is preferable that the airtight processing plate is an epoxy glass FRP.

  It is preferable that the internal pipe is supported on the external duct by a highly insulating FRP angle.

  ADVANTAGE OF THE INVENTION According to this invention, the cable duct for radiation generators which can satisfy all three characteristics, withstand voltage property, high airtightness, and fireproof division property, can be provided.

  When a high-energy proton beam strikes the atomic nucleus that constitutes a substance, the atomic nucleus breaks, generating secondary particles such as neutrons, protons, pions, neutrinos, muons, k mesons, and antiprotons. Using a powerful neutron beam generated in this way, the nuclear transmutation method shortens long-lived nuclei with a long half-life to process radioactive waste, and unknown fine structures of proteins and enzymes. Can be used to develop pharmaceuticals and foods.

  A proton accelerator for generating a high-intensity and high-energy proton beam used for such a purpose is usually composed of a linear linac part and a circular synchrotron part. Protons are gradually accelerated in the linac part and the two large and small synchrotron parts, and finally become a proton beam accelerated to 99.98% of the speed of light.

  FIG. 1 shows a schematic cross-sectional view of the linac portion. In the linac portion 10, the ion source power source chamber 1 and the accelerator tunnel 3 are partitioned by the concrete wall 2, and the inside of the accelerator tunnel 3 becomes a radioactive air generation area. In the ion source power source chamber 1, an ion source power source unit 5 serving as a power source for the ion source is disposed and connected to the ion source 7 by a cable duct 6. A linac 9 is connected to the ion source 7 so that accelerated protons pass through it.

FIG. 2 shows an enlarged view of the cable duct 6.
The basic configuration of the cable duct 6 is a double coaxial structure made of a metal-made cylindrical internal pipe 11 and a square cross-section of an external duct 13, and a cable is laid in the internal pipe 11. The external duct 13 is set to ground potential, and the internal pipe 11 is applied with the same high voltage as the cable to be laid.

  The cable duct 6 is connected to the ion source power supply unit 5 on the left side of the drawing, and is connected to the ion source 7 on the right side of the drawing. The right side of the concrete wall 2 is an activated air generation area. The internal pipe 11 and the external duct 13 are subjected to airtight processing and withstand voltage processing in the airtight processing section A in the figure, and are subjected to fireproof section processing and withstand voltage processing in the fireproof section processing section B.

(Internal piping 11, external duct 13)
Examples of the material of the internal pipe 11 include steel pipes (general-purpose products for electric members), copper pipes, aluminum pipes, and the like, but aluminum pipes are preferable from the viewpoints of electrical characteristics, surface conditions, and costs. Moreover, as a material of the external duct 13, metals, such as stainless steel, aluminum, and iron, can be used. Furthermore, as a member for supporting the internal pipe 11 on the external duct 13, a highly insulating FRP angle 14 is preferably used. With this FRP angle 14, voltage resistance can be imparted.

Next, the airtight processing in the airtight processing unit A will be described.

(Airtight treatment plate 17)
In FIG. 3, the enlarged view of the airtight process board provided in the airtight process part A is shown. The airtight treatment plate 17 is provided for the airtight treatment of the gap between the internal pipe 11 and the external duct 13. Examples of the material of the hermetic treatment plate 17 include epoxy-based aramid FRP, phenol-based glass FRP, epoxy-based glass FRP, melamine-based glass FRP, inorganic-based glass FRP, polyimide-based glass FRP, and silicon-based glass FRP. From the viewpoint of resistance and mechanical strength, epoxy glass FRP is preferred.

  An airtight gasket 22 is provided in the gap between the internal pipe 11 and the airtight treatment plate 17. In the case of this application, it is necessary to check the mounting state of the gasket from the opposite side of the insertion direction. However, for the reason that the sponge-like gasket cannot cope with it and numerical analysis cannot be performed, a circular Y-type gasket is used as the airtight gasket 22. Adopted. As a material of the airtight gasket 22, silicon rubber is preferably used as a result of an electrical property test (experimental example) described later, and chloroprene rubber is not preferable because of its low insulating performance.

  Further, an airtight gasket 24 is also provided in the gap between the external duct 13 and the airtight treatment plate 17. The material of the airtight gasket 24 is preferably a Y-type gasket from the result of taking into account unique numerical analysis and airtight characteristics. As the material of the airtight gasket 24, it is preferable to use silicon rubber.

(Flame retardant sealant 15)
The flame retardant sealing material 15 is filled in the internal pipe for airtight processing of the gap between the cables laid in the internal pipe 11 and the gap between the cable and the internal pipe. As a material of the flame retardant sealing material 15, both "Dan Seal L" (Furukawa Techno Material Co., Ltd.) and "Dan Seal W" (Furukawa Techno Material Co., Ltd.) are used for this purpose as a result of an original airtight characteristic test. However, Dunseal L is more preferable because it also has flame retardancy.

  In the present embodiment, two airtight processing plates 17 and two flame retardant sealing materials 15 are provided in the airtight processing portion A, but the number may be increased or decreased as necessary.

Next, an airtight process in the fire prevention section processing unit B will be described.

(Fire prevention plate 19)
In FIG. 4, the enlarged view of the fire prevention board provided in the fire prevention division process part B is shown. The fire prevention plate 19 is installed as a partition for the fire prevention compartment process between the internal pipe 11 and the external duct 13. As a material of the fire-proofing board 19, a calcium silicate board (calcal board), a fireproof block, etc. are usually raised, but the calcium-based board has received the certification of the fire-proof division processing method as an electric equipment construction besides a construction work. Therefore, a calcium plate is more preferable.

  However, as a result of the inventors' original electrical property test, the ordinary calcium plate alone was found to have low insulation performance and was unsuitable for the radiation generator application. For this reason, as a result of earnest research to provide insulation performance, insulation and voltage resistance are dramatically improved by coating the following two-liquid mixed type partition material on the calcium plate, and this radiation is generated. It was found that it can be suitably used for apparatus applications.

(Two-component mixed partition material)
As basic composition, base polymer (polydiorganosiloxane having vinyl group at the terminal), cross-linking agent (polyorganosiloxane having silicon-bonded hydrogen atoms to connect base polymers together and cross-link to make rubber elastic body), And a curing catalyst such as a platinum compound (1 to 100 ppm), other fillers (reinforcement, weight increase, heat conduction, conductivity, etc.) and other additives (adhesion imparting agent, reaction inhibitor, pigment) Etc.) can be used. In the case of the two-component type, the above essential three components can be combined as a base polymer, a curing catalyst, a B liquid or a curing agent as a crosslinking agent, (base polymer) as a liquid A or a main agent. Specifically, “Silicon seal SE1811” (manufactured by Dow Corning Toray) is a fireproof filler that is airtight and waterproof and has excellent fire resistance. Is optimal. In addition, it is preferable that the coating thickness of the two-liquid mixed type partition material on the fireproof partition plate (calcal plate) is 2 mm in consideration of workability.

(Fireproof material coating 21)
In order to add voltage resistance to the fire prevention compartment processing section B, a fire prevention treatment plate 19 made of a calcium plate coated with a two-component mixed compartment material is used, and the above-mentioned two-liquid mixture type compartment material is further provided in the internal pipe 11. To form a fire protection material coating 21. Specifically, first, a cylindrical mold is made, this mold is attached to the internal pipe 11, and then a liquid two-component mixed partition material is poured into the mold. If left for a while, the liquid partition material solidifies. When the formwork is removed after solidification, the internal pipe 11 is wound with a fireproof compartment material. The winding thickness can be determined according to the withstand voltage performance per 1 mm thickness of the two-component mixed fireproof compartment material according to the result of Experimental Example 1 described later.

That is, when the applied voltage to the pipe 11 is V ₁ [kV], the minimum thickness t [mm] can be obtained from the following equation.
t = (V ₁ / V ₂ ) × α
V ₁ : Applied voltage to piping [kV]
V ₂ : Dielectric strength [kV / mm] of the two-component mixed fireproof compartment material
alpha: safety factor _{time, V 1 = 70 [kV]} , V 2 = 9.5 [kV / mm], and alpha = 2.5, to obtain a minimum thickness t = 18.4 mm. Therefore, the thickness can actually be about 20 mm.

(Cable end airtight material)
It is preferable to apply a sealing material to the cable end portion for airtight treatment between the core wire of the cable end portion laid in the internal pipe 11 and the covering. As the sealing material, a two-component mixed fireproof compartment material can be used.

(Effect of this embodiment)
As explained above, by using the cable duct 6,
(1) Withstand voltage against an applied voltage of 70 kV to the internal piping,
(2) About the airtight processing part, in the airtight test based on JIS A1516, it has a high airtightness of 0.5 m ³ / h or less under a pressure of 0.5 grade or more, specifically 2000 Pa,
(3) It shall have fireproof performance (fireproofing property) in the fired compartment processing part by applying the 25mm calcium plate wall construction method (PS060WL-0236), which is the authorized construction method of the Minister of Land, Infrastructure, Transport and Tourism, and the use of the certified construction method material. it can.

Experimental example 1

(Insulation performance test)
Dielectric breakdown tests were conducted on chloroprene rubber (Takechi Kogyo Rubber), silicon rubber (Takechi Kogyo Rubber), and two-component mixed fireproof compartment material (“Silicone Seal SE1811” manufactured by Toray Dow Corning Silicone). The test method was carried out according to “JIS C2110-1994”, and the type of the test was an insulation breakdown test (short-time breakdown test). The measurement was performed using Type 1 No. 2 insulating oil (oil temperature 22 ° C.) defined in JISC2320, and as shown in FIG. 5, a cylindrical electrode (positive electrode) having a diameter of 25 mm on the top of a sample 31 having a size of 10 × 10 cm. On the other hand, a cylindrical electrode (negative electrode) 35 having a diameter of 75 mm was placed under the sample 31, the sample 31 was submerged in the insulating oil 37, and a voltage was generated by the high voltage generator 39. The voltage increase rate was 2 kV / 20 seconds. The results are shown in the following table.

  From the above results, the average value of the withstand voltage was 10.5 kV / mm for silicon rubber and 9.5 kV / mm for the two-component mixed fireproof compartment, but the insulation performance was too low for chloroprene rubber to measure. Met.

Experimental example 2

(Electrical resistance test)
An electrical resistance test was performed on chloroprene rubber (Takechi Kogyo Rubber), silicon rubber (Takechi Kogyo Rubber), and two-component mixed fireproof compartment material (“Silicone Seal SE1811” manufactured by Toray Dow Corning Silicone). The test method was carried out according to JIS K6249 “Test method for uncured and cured silicone rubber” and K6271 “Vulcanized rubber and thermoplastic rubber—How to obtain volume resistivity and surface resistivity”. A digital ultra-high resistance / microammeter (ADVANTEST R8340) and a resistance measurement sample box (ADVANTEST R12702A) were used as equipment used, and after standing for 16 hours in a 15% humidity atmosphere as a pretreatment, the temperature was 22 ° C. , Humidity 64%, measurement voltage 1000 [V], measurement pressure 3 [kgf]. The results are shown in the following table.

From the above results, the volume resistance of the silicon rubber and the two-component mixed type fireproof compartment material was obtained as 3.6 × 10 ¹⁶ and 1.9 × 10 ¹⁴ Ωcm ³ , respectively. A sufficient value of 3.9 × 10 ⁷ Ωcm ³ could not be obtained.

  From the results of Examples 1 and 2, it was found that the silicon rubber and the two-component mixed fireproof partition material are excellent in insulation performance and are preferable.

It is a schematic sectional drawing which shows the linac part of a proton accelerator. It is an enlarged view which shows the cable duct which concerns on this embodiment. It is an enlarged view which shows the airtight process board provided in the airtight process part A of FIG. It is an enlarged view which shows the fire prevention board provided in the fire prevention division process part B of FIG. 6 is a conceptual diagram of a dielectric breakdown test performed in Experimental Example 1. FIG.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Ion source power supply room 2 Concrete wall 3 Accelerator tunnel 5 Ion source power supply unit 6 Cable duct 7 Ion source 9 Linac 10 Linac part 11 Internal piping 13 External duct 14 FRP angle 15 Flame-resistant sealing material 17 Airtight treatment board 19 Fire prevention board 21 Fireproof coating 22 Airtight gasket 24 Airtight gasket

Claims (4)

  A cable duct for a radiation generator, having at least one side passing through a shielding wall and connected to the inside of the activated air generation area, comprising a double coaxial structure of a metal internal pipe and an external duct, A cable is laid in the pipe and the same voltage as the cable is applied.On the other hand, the external duct is set to the ground potential, and in the airtight processing section, between the internal pipe and the external duct, A glass FRP hermetic treatment plate is provided, and a gasket made of silicon rubber is provided in the gap between the hermetic treatment plate and the internal pipe, and the gap between the hermetic treatment plate and the external duct, and a fire-proof compartment In the processing section, between the internal pipe and the external duct, a fire proof processing plate in which a two-pack type silicone rubber is coated on a calcium silicate plate is provided, The gap between the inner pipe and-proof fire processing board, the radiation generating device for cable ducts, characterized in that a fire protection material coating of two-liquid type silicone rubber.   The cable duct for a radiation generator according to claim 1, wherein when the applied voltage is 70 kV, the thickness of the fireproof material coating is 18.4 mm or more.   2. The cable duct for a radiation generator according to claim 1, wherein the airtight processing plate is an epoxy glass FRP.   2. The cable duct for a radiation generator according to claim 1, wherein the internal pipe is supported on the external duct by a highly insulating FRP angle.

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