JP6710384B2 - Radiation source container - Google Patents

Description

The present invention relates to a radiation source storage container that stores a radiation source when the radiation source that generates radiation such as neutron rays is transported.

Radioisotopes that generate radiation such as neutron rays (hereinafter referred to as "radiation sources") are based on the "Act on Enforcement of the Act on Prevention of Radiation Hazards due to Radioisotopes" outside business sites such as nuclear facilities. It must be transported while being stored in a container designed as follows (hereinafter referred to as "radiation source storage container").

The radiation source storage container is made of a first shielding material (for example, carbon steel capable of shielding gamma rays, lead, etc.) that shields predetermined radiation, and is made of an inner container in which the radiation source is embedded, steel, aluminum, etc. , An outer container for accommodating the inner container.

In this type of radiation source storage container, a second shielding material (for example, hydrogen, boron, etc. capable of shielding neutron rays) that shields a different type of radiation from the first shielding material is provided between the inner container and the outer container. It is known that a resin containing a large amount of atoms is arranged (for example, refer to Patent Document 1).

In the radiation source storage container described in Patent Document 1, when the second shielding material thermally expands due to heat from the external environment, heat from the radiation source, or the like, deformation of the outer container due to an increase in internal pressure due to the thermal expansion. -In order to prevent damage, a predetermined gap is formed between the second shielding material and the outer container by using a spacer or the like to suppress an increase in the internal pressure thereof.

JP, 2001-083296, A

By the way, as a radiation source storage container, a radiation source is embedded in a bottomed tubular main body (a portion corresponding to the outer container and the container configured by the second shielding material in Patent Document 1) having an opening at the top. There is also a type in which the lid is fitted into the opening of the main body after accommodating the radiation source container (the part corresponding to the inner container in Patent Document 1).

Like the main body, the lid is usually configured by disposing the second shielding material inside a container made of steel or the like. Therefore, also in the lid, when the second shielding material thermally expands due to heat from the external environment or heat from the radiation source, like the main body, deformation and damage of the container due to increase in internal pressure due to the thermal expansion. May occur. When the lid is deformed/damaged, the main body in which the lid is fitted may be deformed/damaged.

As a method for preventing such deformation/damage of the lid, as in the configuration of the main body described in Patent Document 1, a predetermined gap is provided between the lid container and the second shielding material disposed inside the container. It is conceivable to form a void to suppress an increase in internal pressure.

However, when such a void is formed in the lid, a region where the second shielding material does not exist is formed around the radiation source, which may lead to a reduction in the radiation shielding performance of the entire radiation source storage container.

The present invention has been made in view of the above points, and an object of the present invention is to provide a radiation source storage container capable of preventing deformation and damage of the container due to thermal expansion while maintaining the radiation shielding performance. ..

In order to achieve the above object, the radiation source storage container of the present invention,
A radiation source is provided in the first shielding material that shields a predetermined radiation inside the main body, which includes a bottomed cylindrical main body having an opening above and a lid fitted in the opening of the main body. A radiation source accommodating container for accommodating an embedded columnar radiation source accommodating body,
The main body is formed of a bottomed tubular first body member and a second shielding material that shields radiation of a different type from the first shielding material, and the bottomed body is disposed inside the first body member. A tubular second main body member,
The second main body member includes a bottom portion having a predetermined thickness, a first tubular portion, which is continuously provided above the bottom portion, into which the radiation source container is fitted, and a second tubular member which is provided above the first tubular portion. And a second tubular portion having an inner diameter larger than that of the first tubular portion and into which the lid is fitted,
A plurality of first protrusions are formed on the outer peripheral surface of the second main body member so as to project radially outward and form a predetermined gap between the second main body member and the first main body member. Was
The lid includes a bottomed tubular first lid member, and a columnar second lid member formed of the second shielding material and disposed inside the first lid member,
A plurality of second projecting portions are formed on the outer peripheral surface of the second lid member so as to project radially outward and form a predetermined gap between the second lid member and the first lid member. is, and the minimum outer diameter of the second cover member is configured larger than the maximum outer diameter of the first portion which is formed in the shielding material of the radiation source housing member, the said first cover member A gap extending in the axial direction of the lid member, which is formed between the second lid member and the second lid member, is located at a position displaced radially outward with respect to the portion formed of the first shielding material . It is characterized by

As described above, in the radiation source storage container of the present invention, the second lid member is provided between the first lid member, which is a container that defines the outer shape of the lid, and the second lid member disposed inside the first lid member. A void is formed by the plurality of second protrusions provided on the outer peripheral surface of the.

As a result, even if the second lid member (second shielding material) inside the lid is thermally expanded, the increase in internal pressure inside the lid is suppressed. As a result, the deformation/damage of the first lid member is prevented.

Further, in this radiation source storage container, in the second main body member made of the second shielding material which constitutes the inner peripheral side portion of the main body, the second main body member is larger than the inner diameter of the first tubular portion (that is, the outer diameter of the radiation source storage body). The inner diameter of the second tubular portion (that is, the outer diameter of the lid) is increased. In addition to this, in the second lid member made of the second shielding material of the lid, the minimum outer diameter (that is, the diameter of the portion excluding the second protruding portion formed on the outer peripheral surface of the second lid member) is It is configured to be larger than the maximum outer diameter of the radiation source container.

Accordingly, when the lid is fitted to the main body, the second shielding material is also present between the radiation source container and the gap between the first lid member and the second lid member of the lid. Become. That is, the radiation source container in which the radiation source is surrounded by the first shielding material that shields predetermined radiation is in a state of being surrounded by the second shielding material having a sufficient thickness without any gap in all directions. As a result, this radiation source storage container can exhibit sufficient shielding performance despite the fact that the lid has a space.

Further, in the radiation source storage container of the present invention,
A ratio of a gap between the first body member and the second body member with respect to a cross-sectional area of the first body member in a plane crossing the axis of the first body member, and a plane crossing the axis of the first lid member. At least one of the cross-sectional areas of the first lid member and the gap between the first lid member and the second lid member is preferably 8% or more.

As described above, it has been experimentally proved that the increase of the internal pressure can be effectively suppressed when the ratio of the voids is 8% or more.

Further, in the radiation source storage container of the present invention,
The second shielding material is preferably paraffin or a thermoplastic resin.

In this way, if a material having high fluidity when heated is adopted as the second shielding material, even if the radiation source accommodating container receives more heat than expected, the second shielding material will be Since it only moves so as to fill the void, the internal pressure is prevented from rising significantly due to the thermal expansion of the second shielding material.

In the radiation source storage container of the present invention, when the second shielding material is paraffin or thermoplastic resin,
In a state in which the radiation source container and the lid are installed on the main body, the second main body member is in a molten state so as to fill a gap between the second main body member and the first main body member. It is preferable that the volume of the second main body is set such that, when the second main body member flows, the upper surface of the second main body member after the flow is maintained at a position higher than the upper surface of the radiation source container.

According to this structure, even when the second main body member largely flows, the state in which the radiation source container is surrounded by the first shielding material and the second shielding material is maintained. This makes it possible to maintain the shielding performance regardless of the state of the second main body member.
Further, in the radiation source storage container of the present invention,
It is preferable that an annular shield plate fitted to the opening of the main body and fixed to the upper surface of the radiation source container is provided.

It is a schematic diagram which shows the cross-sectional shape which follows the axis of the radiation source storage container which concerns on embodiment, and shows the state at the time of conveyance. It is a schematic diagram which shows the cross-sectional shape which follows the axis line of the radiation source storage container of FIG. 1, and shows the state after fixing a lid to a main body after accommodating a radiation source. III-III sectional view taken on the line of the radiation source storage container of FIG. The schematic diagram which shows the cross-sectional shape along an axis line in the state after the paraffin of the radiation source storage container of FIG. 1 is melted. FIG. 5 is a sectional view taken along line VV of the radiation source storage container in FIG. 4. It is a graph which shows the performance of the paraffin used for the radiation source storage container of FIG.

Hereinafter, a radiation source storage container according to an embodiment of the present invention will be described with reference to the drawings.

As shown in FIG. 1, a radiation source storage container C is a container for storing a radiation source 1, which is a radioactive isotope or the like that generates radiation such as neutron rays, when it is transported outside a business site such as a nuclear facility. Is.

The radiation source accommodating container C includes a radiation source accommodating body 2 having a substantially columnar shape for accommodating the radiation source 1, an annular shield plate 3 fixed to an upper surface of the radiation source accommodating body 2, and a bottomed bottom having an opening above. A main body 4 having a tubular shape and capable of accommodating the radiation source container 2 and the shield plate 3 therein, a substantially columnar lid 5 that can be fitted into an opening of the main body 4, and a plurality of units provided below the main body 4. And a plurality of hanging pieces 7 provided above the main body 4.

As shown in FIG. 2, in the radiation source container 2, the first housing member 2a having a bottomed tubular shape and the first housing member 2a are inserted so that their upper end surfaces substantially coincide with each other. The second accommodating member 2b having a thicker bottom and a larger diameter than the first accommodating member 2a is mounted on the second accommodating member 2b and the upper end surface of the first accommodating member 2a and the upper end surface of the second accommodating member 2b. The third accommodating member 2c having an annular shape, and the fourth accommodating member having a bottom and a cylindrical shape and being inserted into the opening of the second accommodating member 2b so as to penetrate the third accommodating member 2c and having a flange at the upper end edge thereof. A container that houses the radiation source 1 is configured with the member 2d.

Further, in the radiation source container 2, a columnar fifth housing member 2e inserted into the fourth housing member 2d and a sixth housing member 2f placed on the upper part of the fifth housing member 2e constitute a lid. Has been done.

The first accommodating member 2a, the third accommodating member 2c, the fourth accommodating member 2d, and the sixth accommodating member 2f are formed of a steel plate which is a lining material. The second housing member 2b and the fifth housing member 2e are formed of a lead material (first shielding material) as a gamma ray shielding material.

The flange of the bottomed tubular fourth housing member 2d having a flange at the upper end and the annular shield plate 3 are fixed to the annular third housing member 2c by bolts from the upper surface side.

After the radiation source 1 is housed, the columnar fifth housing member 2e is inserted into the bottomed tubular fourth housing member 2d. Here, the dimension of the fifth housing member 2e in the axial direction is such that when the fifth housing member 2e is housed in the fourth housing member 2d together with the radiation source 1, the upper end surface of the fifth housing member 2e and the upper surface of the flange portion of the fourth housing member 2d are determined. Have a length that substantially matches. Therefore, the upper end surface of the fifth accommodating member 2e is in contact with the lower surface of the disk-shaped sixth accommodating member 2f placed on the flange of the fourth accommodating member 2d.

The sixth accommodation member 2f is bolted to the flange of the fourth accommodation member 2d. Thereby, the position of the radiation source 1 is fixed inside the radiation source housing 2 via the fifth housing member 2e that is in contact with the lower surface of the sixth housing member 2f.

The shield plate 3 is made of paraffin. The shield plate 3 fills a gap formed between the lid 5 and the radiation source container 2 by a bolt or the like protruding above the radiation source container 2 to shield the radiation source container C as a whole. It has improved performance. The shielding plate 3 may be omitted when the gap between the lid 5 and the radiation source container 2 is very narrow.

The main body 4 is inserted into the first main body member 4a having a bottomed tubular shape having an opening at the top, and the upper end surface of the main body member 4a is substantially aligned with the first main body member 4a, and is thicker than the first main body member 4a. A bottomed cylindrical second main body member 4b, and an annular third main body member 4c which is placed on the upper end surface of the second main body member 4b and has a diameter substantially matching the wall thickness of the second main body member 4b. And a cylindrical fourth main body member 4d inserted into the second main body member 4b.

The 1st main body member 4a, the 3rd main body member 4c, and the 4th main body member 4d are formed by the steel plate which is a lining material. The second main body member 4b is formed of a material that shields radiation of a different type from the lead material, specifically, paraffin (second shielding material).

The bottom surface of the first main body member 4a is configured as a curved surface that is curved so as to project outward in the axial direction. This is because the bottom surface on which the load is concentrated is formed into a curved surface to disperse the pressure applied to the bottom surface due to the thermal expansion of the second main body member 4b and prevent the bottom surface from being deformed or damaged.

Since the bottom surface of the first main body member 4a is a curved surface, the radiation source storage container C cannot stand on its own with the bottom surface of the main body 4 grounded. Therefore, the radiation source storage container C is configured to be self-supporting via the plurality of leg portions 6 provided in the lower portion. Further, each of the leg portions 6 is provided with a hole, and a fixing wire or the like can be locked in the hole.

Note that the bottom surface may have a flat shape as long as it is possible to sufficiently prevent the deformation/damage of the bottom surface of the first main body member 4a by another means such as when the thickness of the steel plate is sufficient.

The second body member 4b is continuously provided above the bottom portion 4b1 and the bottom portion 4b1 having a thickness from the bottom surface of the first body member 4a to the lower surface of the radiation source container 2, and the radiation source container 2 is fitted therein. It is composed of one tubular portion 4b2 and a second tubular portion 4b3 which is continuously provided above the first tubular portion 4b2 and has an inner diameter larger than that of the first tubular portion 4b2 and into which the lid 5 is fitted.

The outer peripheral edge of the annular third main body member 4c is welded to the upper end edge of the first main body member 4a. The inner peripheral edge of the third body member 4c is welded to the upper edge of the cylindrical fourth body member 4d. Further, the lower end edge of the fourth body member 4d is welded to the outer peripheral edge of the annular third housing member 2c of the radiation source housing 2. That is, in the radiation source storage container C, a closed space is formed between the main body 4 and the radiation source storage body 2, and the second main body member 4b formed of the second shielding material is arranged in the closed space. Has become.

As shown in FIG. 3, on the outer peripheral surface of the second main body member 4b, a plurality of first protruding portions 4b4 (first protruding portions) that project radially outward and extend along the axis are arranged at equal intervals. It is provided. A predetermined gap is formed between the second main body member 4b and the first main body member 4a by the first protrusion 4b4.

Thereby, even if the second main body member 4b (second shielding material) inside the main body 4 thermally expands, an increase in internal pressure inside the main body 4 is suppressed. As a result, the first body member 4a, the third body member 4c, the fourth body member 4d, and the lid 5 fitted to the body 4 are prevented from being deformed or damaged.

As shown in FIG. 2, the lid 5 has a bottomed cylindrical first lid member 5a having an opening at the top, and a columnar first lid member 5a inserted into the first lid member 5a such that their upper end surfaces are substantially aligned with each other. The second lid member 5b, the disk-shaped third lid member 5c placed on the upper end surface of the first lid member 5a and the upper end surface of the second lid member 5b, and the upper surface of the third lid member 5c. It is composed of a plurality of eye nuts 5d.

The first lid member 5a and the third lid member 5c are formed of steel plates. The second lid member 5b is formed of a material that shields radiation of a different type from the lead material, specifically, paraffin (second shielding material).

The upper end edge of the bottomed tubular first lid member 5a is welded to the lower surface of the disk-shaped third lid member 5c. That is, in the lid 5, a closed space is formed between the first lid member 5a and the third lid member 5c, and the second lid member 5b formed of the second shielding material is arranged in the closed space. Has become.

As shown in FIG. 3, on the outer peripheral surface of the second lid member 5b, a plurality of second protrusions 5b1 (second protrusions) that protrude radially outward and extend along the axis are arranged at equal intervals. It is provided. A predetermined gap is formed between the second lid member 5b and the first lid member 5a by the second protruding portion 5b1.

As a result, even if the second lid member 5b (second shielding material) inside the lid 5 thermally expands, an increase in internal pressure inside the lid 5 is suppressed. As a result, the first lid member 5a, the third lid member 5c, and the body 4 into which the lid 5 is fitted are prevented from being deformed or damaged.

By the way, as shown in FIGS. 1 and 2, the minimum outer diameter of the second lid member 5b (that is, the outer diameter of the portion excluding the second protrusion 5b1) is formed of the lead material of the radiation source container 2. It is configured to be larger than the maximum outer diameter of the portion (that is, the outer diameter of the second accommodating member 2b).

In addition to this, as described above, in the second main body member 4b made of the second shielding material that constitutes the inner peripheral side portion of the main body 4, the inner diameter of the first tubular portion 4b2 (that is, the outside of the radiation source container 2). The inner diameter of the second tubular portion 4b3 (that is, the outer diameter of the lid 5) is larger than the diameter thereof.

Thereby, when the lid 5 is fitted to the main body 4, the second shield is also provided between the radiation source container 2 and the space between the first lid member 5a and the second lid member 5b of the lid 5. The material paraffin is present.

That is, the radiation source container 2 that surrounds the radiation source 1 with lead, which is the first shielding material, is in a state surrounded by paraffin, which is the second shielding material having a sufficient thickness, with no gap in all directions. .. As a result, this radiation source storage container C is able to exhibit sufficient shielding performance despite the fact that the lid 5 has a space.

Holes are formed in the plurality of suspension pieces 7 provided above the main body 4. The radiation source container C is moved by suspending a hook of a transportation crane or the like on an eye nut 5d attached to the hole of the hanging piece 7 and the upper surface of the third lid member 5c of the lid 5.

Next, the paraffin which is the second shielding material forming the second body member 4b and the second lid member 5b will be described.

As a paraffin for shielding neutron rays, a paraffin having a melting point of 88 degrees Celsius is used. Such paraffins are based on the technical standards (temperature range of -40 degrees Celsius to 70 degrees Celsius) for type A packages specified in the "Law Enforcement Regulations for Prevention of Radiation Hazards due to Radioisotopes, etc." In the performance test, it has been proved that cracks and damages do not occur although thermal expansion occurs.

By the way, the performance test is usually performed using a sample formed only of paraffin material, and like the radiation source storage container C of the present embodiment, the periphery thereof is surrounded by a steel material as a lining material and hermetically sealed. It is not done with the sample. Therefore, in an actual product, it is considered preferable to sufficiently consider the influence of the thermal expansion of the paraffin material (that is, the increase in the internal pressure), which is not a problem in the performance test.

Therefore, in the radiation source storage container C of the present embodiment, as shown in FIG. 3, a plurality of first ridges 4b4 (first protrusions) protruding outward in the radial direction are formed on the outer peripheral surface of the second main body member 4b. Parts) are provided at equal intervals, and the first protrusion 4b4 forms a predetermined gap between the second main body member 4b and the first main body member 4a.

Further, on the outer peripheral surface of the second lid member 5b, a plurality of second protrusions 5b1 (second protrusions) protruding outward in the radial direction are provided at equal intervals, and by the second protrusions 5b1, A predetermined gap is formed between the second lid member 5b and the first lid member 5a.

In the radiation source storage container C in which these voids are formed, even if more heat than expected is applied to the radiation source storage container C, the paraffin only moves so as to fill the voids. A large increase in internal pressure due to thermal expansion is prevented.

In order to obtain such an effect of preventing the rise of the internal pressure, it is sufficient that the second shielding material can obtain fluidity by heating. For example, instead of paraffin, a thermoplastic resin may be adopted.

Further, as shown in FIGS. 4 and 5, in the radiation source container C, the paraffin is in a molten state in the state where the radiation source container 2 and the lid 5 are installed on the body 4, and the first body member 4a. When flowing so as to fill the space between the second main body member 4b and the second main body member 4b, the upper surface of the second main body member 4b (specifically, the second tubular portion 4b3) after the flow is the radiation source container 2 The volume of the second main body member 4b is set so as to be maintained at a position higher than the upper surface of the second main body member 4b.

As a result, even if the paraffin composing the second main body member 4b becomes so fluid as to have a very high fluidity (ie, regardless of the state of the second main body member 4b), the radiation source The surrounding of the container 2 is kept surrounded by the lead material that is the first shielding material and the paraffin that is the second shielding material having a sufficient thickness, and the shielding performance is maintained.

If a resin or the like having a high melting point is used as the second shielding material, the possibility that the second shielding material will flow is reduced to such an extent. In such a case, when the volume of the second main body member 4b flows, the upper surface of the second main body member 4b after the flow is maintained at a position higher than the upper surface of the radiation source container 2 after the flow. The volume does not have to be set.

Here, the size of the void formed by using the protrusion will be described.

As shown in FIG. 3, the gap formed between the first main body member 4a and the second main body member 4b of the main body 4 is a gap between the first main body member 4a and a plane that intersects the axis of the first main body member 4a. The ratio to the area is 8% or more. Similarly, the gap formed between the first lid member 5a and the second lid member 5b of the lid 5 has a ratio with respect to the cross-sectional area of the first lid member 5a in the plane that intersects the axis of the first lid member 5a. It is configured to be 8% or more.

As described above, when the ratio of the voids is 8% or more, it is experimentally found that the increase of the internal pressure can be effectively suppressed while the thickness of the body of the second main body member 4b or the second lid member 5b is suppressed. It turns out. The details of the experiment will be described below.

In this experiment, an expansion force measuring device was placed inside the thermostat, the temperature inside the thermostat was raised from room temperature to 70 degrees Celsius, and the expansion force was measured at a holding time of 70 degrees Celsius.

As the expansive force measuring machine, a machine constituted by a cylinder tube into which a substantially columnar paraffin material can be inserted, and a cylinder rod that comes into contact with the end surface of the paraffin material inserted into the cylinder tube was used. As the sample, a substantially columnar one having a buffer space (void) calculated from the volume of the paraffin material in the outer peripheral portion was used. There were three types of buffer void ratio: 0%, 5%, and 8%.

As a method for measuring the temperature of the sample, a thermocouple was attached to the surface of the expansive force measuring machine and the temperature was confirmed. The expansion force of the sample was measured by detecting the pressing force of the cylinder lot with a load cell and converting it with a force gauge.

A graph of the experimental results relating to the above experiment is shown as FIG. In FIG. 6, the vertical axis represents the expansion force, and the horizontal axis represents the holding time of the heated state.

As shown in FIG. 6, it was inferred that the sample having a buffer space ratio of 0% and the sample having a buffer space ratio of 5% had a rapid increase in expansion force as the holding time increased. Therefore, it is estimated that the expansion force increases in proportion to the holding time even for the sample having the buffer space ratio of 8%.

In addition, comparing the expansive force of each sample when kept in an environment of 70 degrees Celsius for 40 minutes, the buffer space ratio of 0% was about 935N, the 5% sample was about 580N, and the 8% sample was about 315N. Expansive force is generated. When this expansion force is converted into a pressure, a pressure of about 0.59 MPa is generated for a sample having a buffer space ratio of 0%, a pressure of about 0.36 MPa is generated for a sample of 5%, and a pressure of about 0.20 MPa is generated for a sample of 8%.

Here, when calculating the thickness of the cylinder of the lining material, it is known that the thickness required for the calculation of the cylinder is proportional to the maximum working pressure. Based on this, assuming that the thickness required for the calculation of the cylinder calculated from the pressure of the sample with the buffer space ratio of 0% is 1, it is about 0.61 for the 5% sample and about 0.34 for the 8% sample. It can be estimated that the same performance as that of the 0% sample can be obtained with the thickness of.

That is, when the radiation source storage container is manufactured, the volume of the paraffin material is reduced to about 92% rather than the volume of the paraffin material that is close to 100% (that is, the buffer void ratio is 0%). That is, it was found that when the buffer space ratio was 8%), the thickness required for the calculation of the cylinder can be suppressed to about 1/3. That is, it was found that by setting the buffer void ratio (void) to 8% or more, it is possible to effectively suppress an increase in internal pressure while suppressing the thickness of the case.

Although the illustrated embodiment has been described above, the present invention is not limited to such an embodiment.

For example, in the above embodiment, lead is used as the first shielding material and paraffin is used as the second shielding material. However, the shielding material of the present invention is not limited to these, and the two shielding materials may be those that shield different types of radiation.

Further, in the above-described embodiment, a gap is formed between the first main body member 4a and the second main body member 4b by the first ridge portion 4b4, and the first lid member 5a is formed by the second ridge portion 5b1. And a second lid member 5b is formed with a gap. However, the first projecting portion and the second projecting portion of the present invention need only project outward in the radial direction, and need not extend along the axis.

For example, a plurality of protrusions may be arranged at intervals along the axis to form a line, and the line may be arranged in the circumferential direction. Further, one protrusion may be arranged in the circumferential direction.

In addition, in the above-described embodiment, the gap formed between the first body member 4a and the second body member 4b of the body 4 is defined by the gap between the first body member 4a and the first body member 4a in the plane that intersects the axis of the first body member 4a. The ratio to the cross-sectional area is 8% or more.

Similarly, the gap formed between the first lid member 5a and the second lid member 5b of the lid 5 has a ratio with respect to the cross-sectional area of the first lid member 5a in the plane that intersects the axis of the first lid member 5a. It is configured to be 8% or more.

However, the proportion of the voids in the present invention is not necessarily set to 8% or more in both the main body and the lid, and the size may be appropriately changed depending on the shapes of the main body and the lid.

DESCRIPTION OF SYMBOLS 1... Radiation source, 2... Radiation source accommodation body, 2a... 1st accommodation member, 2b... 2nd accommodation member, 2c... 3rd accommodation member, 2d... 4th accommodation member, 2e... 5th accommodation member, 2f... 6 housing member, 3... Shielding plate, 4... Main body, 4a... 1st main body member, 4b... 2nd main body member, 4b1... Bottom part, 4b2... 1st cylindrical part, 4b3... 2nd cylindrical part, 4b4... DESCRIPTION OF SYMBOLS 1 ridge part (1st protrusion part), 4c... 3rd main body member, 4d... 4th main body member, 5... Lid, 5a... 1st lid member, 5b... 2nd lid member, 5b1... 2nd ridge part (Second protrusion) 5c... Third lid member, 5d... Eye nut, 6... Leg, 7... Hanging piece, C... Radiation source storage container.

Claims (5)

A radiation source is provided in the first shielding material that shields a predetermined radiation inside the main body, which includes a bottomed cylindrical main body having an opening above and a lid fitted in the opening of the main body. A radiation source accommodating container for accommodating an embedded columnar radiation source accommodating body,
The main body is formed of a bottomed tubular first body member and a second shielding material that shields radiation of a different type from the first shielding material, and the bottomed body is disposed inside the first body member. A tubular second main body member,
The second main body member includes a bottom portion having a predetermined thickness, a first tubular portion, which is continuously provided above the bottom portion, into which the radiation source container is fitted, and a second tubular member which is provided above the first tubular portion. And a second tubular portion having an inner diameter larger than that of the first tubular portion and into which the lid is fitted,
A plurality of first protrusions are formed on the outer peripheral surface of the second main body member so as to project radially outward and form a predetermined gap between the second main body member and the first main body member. Was
The lid includes a bottomed tubular first lid member, and a columnar second lid member formed of the second shielding material and disposed inside the first lid member,
A plurality of second projecting portions are formed on the outer peripheral surface of the second lid member so as to project radially outward and form a predetermined gap between the second lid member and the first lid member. is, and the minimum outer diameter of the second cover member is configured larger than the maximum outer diameter of the first portion which is formed in the shielding material of the radiation source housing member, the said first cover member A gap extending in the axial direction of the lid member, which is formed between the second lid member and the second lid member, is located at a position displaced radially outward with respect to the portion formed of the first shielding material . A radiation source storage container characterized by the above. The radiation source storage container according to claim 1,
A ratio of a gap between the first body member and the second body member with respect to a cross-sectional area of the first body member in a plane crossing the axis of the first body member, and a plane crossing the axis of the first lid member. At least one of the ratios of the voids of the first lid member and the second lid member in the cross-sectional area of the first lid member is 8% or more. The radiation source storage container according to claim 1 or 2,
The radiation source storage container, wherein the second shielding material is paraffin or a thermoplastic resin. The radiation source storage container according to claim 3,
In a state in which the radiation source container and the lid are installed on the main body, the second main body member is in a molten state so as to fill a gap between the second main body member and the first main body member. The volume of the second main body member is set such that, when the second main body member flows, the upper surface of the second main body member after the flow is maintained at a position higher than the upper surface of the radiation source container. Radiation source storage container. The radiation source storage container according to any one of claims 1 to 4,
A radiation source storage container, comprising an annular shield plate fitted into the opening of the main body and fixed to an upper surface of the radiation source storage body.