JP2003180800A - Radiation sterilization method and radiation sterilization device - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a radiation sterilization technique which is free from trouble or breakdown, has a long period of durability, is low cost and economical, and exhibits high safety without the generation of a radioactive waste, by using a natural ore adjusted to a low level radiation instead of mechanically irradiating radiation. <P>SOLUTION: The method is to sterilize by directly applying radiation on an article to be sterilized by a radioactive material containing the natural ore (a raw ore containing RE, Th, PO, Tho2, etc.), which emits radiation. A tunnel-shaped structure 2 in the inside of which a passage space 20 for the article to be sterilized is formed using a radioactive member 1 having the radioactive material, and a conveyer 3 for conveying the article to be sterilized so as to pass it through the passage space of this tunnel-shaped structure are disposed. Sterilization is executed by forming the upper face and both right and left side faces of the passage space as an irradiation surface, and by irradiating radiation on the article to be sterilized conveyed on the conveyer. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a radiation sterilization method and a radiation sterilization apparatus using natural ores (crude ores containing RE, Th, PO, Tho2, etc.) that emit radiation.

[0002]

2. Description of the Related Art Conventionally, techniques for sterilizing an object to be sterilized by irradiating with an electron beam or radiation have been widely used, but these have a problem that they are expensive and difficult to introduce. In addition, radioactive waste may be generated, and it may be difficult to dispose of it. The equipment is difficult to operate and has a complicated structure, which causes troubles and failures. There was a problem that needed. Incidentally, there is a problem that the electron beam has no effect when the substance to be sterilized is a liquid.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, in which natural ore is adjusted to a low level of radiation, rather than mechanical irradiation of radiation. By using it, there is no trouble or failure, the service life is long, the cost is low, and it is economical.
It is an object of the present invention to provide a radiation sterilization method and a radiation sterilization apparatus that do not generate radioactive waste and have high safety.

[0004]

In order to solve the above problems, the radiation sterilization method of the present invention (claim 1) is a crude ore containing natural ores (RE, Th, PO, Tho2, etc.) that emit radiation. ) Is used to sterilize the object to be sterilized by directly irradiating it with radiation. The sterilized products include foods, tableware, container / packaging materials, medical devices / equipment, medical wastes, industrial wastes, and various sterilized products, which may be solid or liquid.

In the radiation sterilization method of the present invention, the radioactive substance is formed by mixing natural ore that emits radiation into cement and molded into a solid, and the radiation concentration is adjusted to 370 pecquerel / g or less. There is a mode (Claim 2). The Act on Nuclear Fuel Materials, Nuclear Source Materials and Reactor Regulations (Sho 32) stipulates that the concentration of radiation-enriched uranium and thorium that can be used with or without notification as nuclear source materials is 370 pq / g or less. ,
According to this regulation, the radiation concentration of the radioactive substance used in the present invention is adjusted to 370 pecryl / g or less.

Further, in the radiation sterilization method of the present invention, the radioactive substance is a solid formed by mixing natural ore that emits radiation with sand or pebbles and mixing it with water glass or an adhesive. Yes, radiation concentration is 370 pechrel / g
There is an aspect (claim 3) that is adjusted below. When a mixture of natural ore with sand or pebbles is mixed with water glass, it can be dried and then fired at 350 ° C. or higher.

In the radiation sterilization method of the present invention, the radioactive substance is formed by mixing natural ore emitting radiation with plastic or rubber to form a solid, and the radiation concentration is adjusted to 370 pequerel / g or less. There is a mode (Claim 4) which is the one that has been described.

In the radiation sterilization method of the present invention, the radioactive substance is mixed with a crushed product of a natural ore which emits radiation, and a crushed product of ore clay (feldspar, quartz clay, porcelain, etc.) or / and alumina. There is an embodiment (claim 5) in which the composition is formed into a solid by firing at 1000 ° C. or higher and the radiation concentration is adjusted to 370 pecquerel / g or less.

In the method of sterilizing radiation according to the present invention, the radioactive substance is a mixture of natural ore that emits radiation and sand or pebbles, which is coated on the surface of metal, plastic, wood or the like with an adhesive or the like. There is an aspect (claim 6) in which the radiation concentration is adjusted to 370 pecryl / g or less.

The radiation sterilizer of the present invention (claim 7).
Is a radiation sterilization apparatus using the above-mentioned radiation sterilization method, a radioactive substance is provided in a plate shape, a cylindrical shape, a semi-cylindrical shape, provided with a radioactive member processed into a spherical shape, etc. / And the structure is formed so as to irradiate the radiation from the side surface or the entire surface.

In the radiation sterilization apparatus of the present invention, the structure is formed into a tunnel-shaped structure having a passage space for the sterilization object formed therein, and the member radiating to the sterilization object while passing through the passage space. There is a mode (claim 8) in which radiation is emitted from the. In this case, as a means for passing through the passage space, a tunnel-like structure is installed vertically or diagonally, the sterilized object is put in from above the passage space, and the passage space is dropped or slid to pass therethrough. It can be taken out from under the space.

Further, in the radiation sterilization apparatus of the present invention, the structure is formed in a tunnel-shaped structure, and a conveyor is provided to convey the sterilized object so as to pass through the passage space of the tunnel-shaped structure ( Claim 9) exists. In this case, the radioactive member may be attached to the conveyor (claim 10).

Further, in the radiation sterilization apparatus of the present invention, there is a mode in which a portion other than the radiation irradiation surface of the radioactive member is covered with a lead plate to block radiation irradiation (claim 11). In this way, by shielding the portion other than the radiation irradiation surface with the lead plate, it is possible to irradiate only the object to be sterilized that requires sterilization while limiting the irradiation range of the radiation, and the safety of the structure is improved. It is possible to improve.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION Natural ore (hereinafter simply referred to as "natural ore") that emits radiation of 1280 pecryl / g. 3
When 0% and 70% of cement were mixed and dried and solidified, a radioactive substance having a radiation concentration of 370 pecquerel / g could be obtained, and the bactericidal effect was remarkable. In this case, if the ratio of the natural ore is 10% or less, the bactericidal effect (radiation concentration) is reduced, so it is preferable to set the ratio of the natural ore to 20 to 30%.

30% natural ore of 1280 pequerels / g
55% of pebbles with different particle sizes, and water glass 1
When mixed with 5%, dried and calcined at 600 ° C., a radioactive substance having a radiation concentration of 370 pecquerel / g was obtained, and the bactericidal effect was remarkable. Also in this case, if the ratio of natural ore is 10% or less, the bactericidal effect (radiation concentration) decreases, so the ratio of natural ore is 20 to 30%.
Is preferred. When the firing temperature is 400 ° C. or lower, the obtained radioactive substance is easily dissolved in water and easily recycled.

30% natural ore of 1280 pequerels / g
And 70% of plastic (or rubber) were mixed and dried and solidified, a radioactive substance having a radiation concentration of 370 pecquerel / g was obtained, and the bactericidal effect was remarkable.
Also in this case, if the ratio of the natural ore is 10% or less, the bactericidal effect (radiation concentration) is lowered, so that the ratio of the natural ore is preferably 20 to 30%.

30% natural ore of 1280 pequerels / g
And 70% of clay (or alumina) were mixed, dried and baked at 1200 ° C. for 24 hours.
70 pechrel / g of radioactive material could be obtained. The radioactive substance thus obtained was processed into a plate-shaped ceramic having a thickness of 2 cm and a size of 40 cm, and 2 kg of buckwheat fir was directly irradiated with radiation for 2 minutes from above. As a result, Escherichia coli (4800 specimens), general bacteria ( The number of specimens 220,000)
Both became zero after irradiation, and a remarkable bactericidal effect could be obtained. Also in this case, if the ratio of the natural ore is 10% or less, the bactericidal effect (radiation concentration) is lowered, so that the ratio of the natural ore is preferably 20 to 30%. If the firing temperature is not 1000 ° C. or higher, the strength is weak and the glass tends to collapse, but it is not necessary to raise the temperature to 1500 ° C.

[0018]

1 is a perspective view showing a radiating member according to a first embodiment of the present invention. In this radioactive member 1, a lead plate 11 is attached to an inner surface of a box body 10 formed of a stainless steel plate, and a plate-like body (cylindrical body, semi-body) of a radioactive substance 12 containing the natural ore molded as described above is provided therein. (Cylindrical body, spherical body etc.)
The irradiation of the radiation from the part excluding the irradiation surface 13 is blocked. And the irradiation surface 1 of this radioactive member 1
From 3, the object to be sterilized is irradiated with radiation from the upper surface, the side surface, the entire surface, etc. to sterilize.

Next, FIG. 2 is a perspective view of a radiation sterilizer according to a second embodiment of the present invention. This radiation sterilizer
A plurality of radioactive members 1 are combined to convey the sterilized object so that the tunnel-shaped structure 2 in which the passage space 20 of the sterilized object is formed and the passage space 20 of the tunnel-shaped structure 2 are passed. A conveyor 3 is provided. And
The upper surface and the left and right side surfaces of the passage space 20 are formed as irradiation surfaces so that the object to be sterilized carried on the conveyor 3 is irradiated with radiation to be sterilized. In addition, each radioactive member 1
A handle 14 is attached to this so that the tunnel-shaped structure 2 can be easily maintained, moved, and assembled.

Next, FIG. 3 is a perspective view of a radiation sterilizer according to a third embodiment of the present invention. This radiation sterilizer
Using the radioactive member 1, a tunnel-shaped structure 2 in which a passage space 20 for the sterilized object is formed, and a conveyor 3 for conveying the sterilized object so as to pass through the passage space 20 of the tunnel-shaped structure 2. I have it. In addition, 21 is a leg. In this case, a charging hopper 41 is provided at one end of the tunnel-shaped structure 2 via a charging chute 40, and a recovery container 51 is provided at the other end of the tunnel-shaped structure 2 via a discharge chute 50. ing. Further, as shown in FIG. 4, a large number of plate-shaped radioactive members 6 are attached to the belt of the conveyor 3 with a space 60 in the direction orthogonal to the transfer direction. By providing the gap 60, the belt can be rotated while the plate-shaped radioactive member 6 is attached.
In this case, the belt surface may be coated with a radioactive member. Then, the charging hopper 41 to the charging chute 40
The material to be sterilized is supplied to one end of the conveyer 3 through the conveyor 3, and when the material to be sterilized is accompanied by the operation of the conveyor 3, the irradiation surface formed on the upper surface and the left and right side surfaces of the passage space 20 changes the material to be sterilized. In addition to being irradiated with radiation, the radioactive material 6 attached to the conveyor 3 is also irradiated with radiation to sterilize the object to be sterilized, and is collected in the collection container 51 via the discharge chute 50. Further, on the side surface (or the upper surface) of the tunnel-shaped structure 2, a water tank-shaped peep window 22 containing water between double transparent glass plates (or transparent plastic plates) is provided.
Is provided, and the passing space 20 can be monitored through this.

Next, FIG. 5 is a perspective view of a radiation sterilizer according to a fourth embodiment of the present invention. This radiation sterilizer
The tunnel-shaped structure 2 in which the passage space 20 of the sterilized object is formed by using the radioactive member 1 is provided, and the entire inner peripheral surface of the passage space 20 is formed as an irradiation surface. Further, a charging hopper 41 is provided at one end of the tunnel-shaped structure 2 via a charging chute 40, and a recovery container 51 is provided at the other end of the tunnel-shaped structure 2 via a discharging chute 50. Then, the material to be sterilized is dropped and supplied from the input hopper 41 through the input chute 40 into the passage space 20 of the tunnel-shaped structure 2 and is passed through the passage space 20 by its force, and is formed on the entire surface of the passage space 20. The object to be sterilized is irradiated with radiation from the irradiation surface and sterilized, and is collected in the collection container 51 via the discharge chute 50.

Next, FIG. 6 is a perspective view of a radiation sterilizer according to a fifth embodiment of the present invention. In this radiation sterilizer, a well-shielding shield member 7 is attached to the both ends of the tunnel-shaped structure 2 and in front of and behind it. Shield member 7 on this
For example, as shown in FIG. 7, a large number of lead plates 71 are arranged on a rubber plate 70 at intervals 72, and FIG.
As shown in FIG. 3, there is a plastic plate 73, 73 in which a lead plate 74 is sandwiched and a hinge 75 is attached to the upper edge thereof. By providing this shielding member 7, it is possible to suppress leakage of radiation to the outside in the passage space 20 and during conveyance of the conveyor 3, and it is possible to improve safety.

FIG. 9 shows a storage container for the sterilization object. The storage container 8 is a box body 80 made of a stainless steel plate having lead plates 81, 81 attached to the front and rear surfaces thereof. By passing the space to be sterilized in the container 8 through the passage space, leakage of radiation is suppressed.

[0024]

As described above, according to the radiation sterilization method and the radiation sterilization apparatus of the present invention, natural ore is adjusted to a low level of radiation and used, rather than mechanical irradiation of radiation. The advantages are that there is no trouble or failure, the service life is long, the cost is low and the operation is economical, the radioactive waste is not generated, and the safety is high.

[Brief description of drawings]

FIG. 1 is a perspective view showing a radioactive member that is a first embodiment of the present invention.

FIG. 2 is a perspective view of a radiation sterilizer according to a second embodiment of the present invention.

FIG. 3 is a perspective view of a radiation sterilizer according to a third embodiment of the present invention.

FIG. 4 is a perspective view of a conveyor.

FIG. 5 is a perspective view of a radiation sterilizer according to a fourth embodiment of the present invention.

FIG. 6 is a perspective view of a radiation sterilizer according to a fifth embodiment of the present invention.

FIG. 7 is a front view showing an example of a shielding member.

FIG. 8 is a perspective view showing an example of a shielding member.

FIG. 9 is a perspective view showing a container for storing a material to be sterilized.

[Explanation of symbols]

1 radioactive member 10 box bodies 11 Lead plate 12 Radioactive material 13 Irradiated surface 14 Handle 2 tunnel-like structures 20 passing space 21 legs 22 Peep window 3 conveyors 40 throw chute 41 Input hopper 50 discharge chute 51 collection container 6 radioactive members 60 intervals 7 Shielding member 70 rubber plate 71 Lead plate 72 intervals 73 plastic plate 74 Lead plate 75 hinges 8 storage containers 80 box body 81 Lead plate

Claims (11)

[Claims] 1. A natural ore that emits radiation (RE, T
(a crude ore containing h, PO, Tho2, etc.) is sterilized by directly irradiating the material to be sterilized with a radioactive substance. 2. The radioactive substance is formed by mixing natural ore that emits radiation with cement into a solid,
The radiation sterilization method according to claim 1, wherein the radiation concentration is adjusted to 370 pecryl / g or less. 3. The radioactive substance is formed by mixing natural ore that emits radiation with sand, pebbles, etc., into water glass, an adhesive, or the like, and molding it into a solid.
The radiation sterilization method according to claim 1, wherein the radiation sterilization method is adjusted to 70 pecryl / g or less. 4. The radioactive substance is formed by mixing natural ore that emits radiation with plastic or rubber and molded into a solid, and the radiation concentration is adjusted to 370 pecryl / g or less. The radiation sterilization method according to 1. 5. The radioactive substance is obtained by mixing a pulverized product of natural ore that emits radiation with a pulverized product of ore clay and / or alumina and firing the mixture at 1000 ° C. or higher to form a solid. The radiation sterilization method according to claim 1, wherein the concentration is adjusted to 370 pecryl / g or less. 6. The radioactive material is a mixture of natural ore that emits radiation and sand or pebbles, which is coated on the surface of metal, plastic, wood, etc., and the radiation concentration is 370 pecquerel / g or less. The radiation sterilization method according to claim 1, which is prepared. 7. A radiation sterilization apparatus using any one of the radiation sterilization methods according to claim 1, comprising a radioactive member obtained by processing a radioactive substance into a plate shape, a cylinder shape, a semi-cylindrical shape, a spherical shape, or the like. , This radioactive member is on the top surface of the object to be sterilized or /
And a radiation sterilizer, which is formed on a structure attached so as to emit radiation from the side surface or the entire surface. 8. The radiation sterilizer according to claim 7, wherein the structure is formed in a tunnel-like structure having a space through which the object to be sterilized is formed, and the object to be sterilized while passing through the passage space. A radiation sterilizer that radiates radiation from a radioactive member. 9. The radiation sterilization apparatus according to claim 7, wherein the structure is formed in a tunnel-shaped structure, and a conveyor is provided to convey the sterilized object so as to pass through a passage space of the tunnel-shaped structure. Radiation sterilizer. 10. The radiation sterilizer according to claim 9, wherein a radioactive member is attached to the conveyor. 11. The radiation sterilizer according to claim 7, wherein a portion of the radioactive member other than the radiation irradiation surface is covered with a lead plate to block radiation irradiation.