JP2018194447A - Radiation source storage container - Google Patents

Abstract

To provide a radiation source storage container capable of preventing deformation and breakage of the container due to thermal expansion, while maintaining the shield performance of radiation.SOLUTION: A radiation source storage container C is stored with a lead radiation source storage container 2. A main body 4 includes: a first bottomed cylindrical main body member 4a; and a second bottomed cylindrical main body member 4b on which a first ridge part 4b4 for forming a predetermined gap with the first main body member 4a is provided on the outer circumferential surface when inserted into the first main body member 4a. The lid 5 includes: a first bottomed cylindrical lid member 5a and a second columnar lid member 5b in which the second ridge part 5b1 for forming the predetermined gap with the first lid member 5a when inserted into the first lid member 5a is provided on the outer circumferential surface. The smallest outer diameter of the second lid member 5b is larger than the maximum outer diameter of a portion formed with a lead of the radiation source storage container 2.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a radiation source storage container that stores a radiation source that generates radiation such as a neutron beam.

  Radioisotopes that generate radiation such as neutrons (hereinafter referred to as “radiation sources”) are based on the “Regulation for Enforcement of Law Concerning the Prevention of Radiation Hazards due to Radioisotopes, etc.” outside facilities such as nuclear facilities. It must be transported in a state where it is contained in a container designed in this manner (hereinafter referred to as “radiation source container”).

  The radiation source container is made of a first shielding material that shields predetermined radiation (for example, carbon steel or lead that can shield gamma rays), and is made of an inner container in which the radiation source is embedded, steel, aluminum, or the like. And an outer container containing the inner container.

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

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

JP 2001-083296 A

  By the way, as a radiation source storage container, a radiation source is embedded in a bottomed cylindrical main body (a portion corresponding to a container composed of an outer container and a second shielding material in Patent Document 1) having an opening above. There is a type in which a radiation source container (portion corresponding to the inner container in Patent Document 1) is accommodated and then a lid is fitted into the opening of the main body.

  The lid is usually configured by arranging a second shielding material inside a container made of steel or the like, like the main body. Therefore, in the case of the lid as well as the main body, when the second shielding material is thermally expanded due to heat from the external environment or heat from the radiation source, the container is deformed or damaged due to an increase in internal pressure due to the thermal expansion. May occur. When the lid is deformed / damaged, the main body into which the lid is fitted may be deformed / damaged.

  As a method for preventing such deformation and breakage of the lid, as in the configuration of the main body described in Patent Document 1, a predetermined amount is provided between the lid container and the second shielding material disposed inside the container. A method of suppressing the increase of the internal pressure by forming a gap of the above is conceivable.

  However, when such a gap is formed in the lid, a region where the second shielding material does not exist around the radiation source is formed, and there is a possibility that the radiation shielding performance as the whole radiation source container is deteriorated.

  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 container that can prevent deformation and breakage of the container due to thermal expansion while maintaining radiation shielding performance. .

In order to achieve the above object, the radiation source container according to the present invention comprises:
A bottomed cylindrical main body having an opening above and a lid fitted to the opening of the main body, and a radiation source is provided in the first shielding material that shields predetermined radiation inside the main body A radiation source storage container for storing an embedded columnar radiation source container,
The main body is formed of a bottomed cylindrical first main body member and a second shielding material that shields different types of radiation from the first shielding material, and is disposed within the first main body member. A cylindrical second body member,
The second main body member includes a bottom portion having a predetermined thickness, a first tubular portion into which the radiation source container continuously provided above the bottom portion is fitted, and a continuous portion above the first tubular portion. An inner diameter larger than that of the first tubular portion, and a second tubular portion 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 protrude outward in the radial direction and to form a predetermined gap between the second main body member and the first main body member. And
The lid includes a bottomed cylindrical 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 outward in the radial direction and form a predetermined gap between the second lid member and the first lid member. And
A minimum outer diameter of the second lid member is configured to be larger than a maximum outer diameter of a portion formed of the first shielding material of the radiation source container.

  Thus, in the radiation source storage container of the present invention, the second lid member is disposed between the first lid member that is a container that defines the external shape of the lid and the second lid member disposed inside the first lid member. An air gap is formed by the plurality of second protrusions provided on the outer peripheral surface of the first protrusion.

  Thereby, even if the 2nd cover member (2nd shielding material) inside a lid | cover expands thermally, the raise of the internal pressure in the inside of a lid | cover is suppressed. As a result, deformation and breakage of the first lid member are prevented.

  Moreover, in this radiation source storage container, in the 2nd main body member made from the 2nd shielding material which comprises the inner peripheral part of a main body, rather than the internal diameter (namely, outer diameter of a radiation source storage body) of a 1st cylindrical part The inner diameter of the second cylindrical portion (that is, the outer diameter of the lid) is configured to be large. In addition to this, in the second lid member made of the second shielding material of the lid, its minimum outer diameter (that is, the diameter of the portion excluding the second protrusion formed on the outer peripheral surface of the second lid member) It is comprised so that it may become larger than the largest outer diameter of a radiation source container.

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

In the radiation source container of the present invention,
The ratio of the gap between the first main body member and the second main body member to the cross-sectional area of the first main body member in the plane crossing the axis of the first main body member, and the plane crossing the axis of the first lid member It is preferable that at least one of the ratio of the gap between the first lid member and the second lid member in the cross-sectional area of the first lid member is 8% or more.

  Thus, it has been experimentally found that the increase in internal pressure can be effectively suppressed when the void ratio is 8% or more.

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

  As described above, when a material having high fluidity when heated is adopted as the second shielding material, even if more heat than expected is applied to the radiation source container, the second shielding material is Since it only moves so as to fill the gap, the internal pressure is prevented from significantly increasing due to the thermal expansion of the second shielding material.

Moreover, in the radiation source storage container of the present invention, when the second shielding material is paraffin or a thermoplastic resin,
In a state where the radiation source container and the lid are installed with respect to 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. When flowing, it is preferable that the volume of the second main body is set so that 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.

  If comprised in this way, even if it is a case where the 2nd main body member flows largely, the state where the circumference | surroundings of the radiation source container were enclosed with the 1st shielding material and the 2nd shielding material is maintained. Thereby, it becomes possible to maintain shielding performance irrespective of the state of the second main body member.

It is a schematic diagram which shows the cross-sectional shape which follows the axis line 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 in alignment with the axis line of the radiation source storage container of FIG. 1, and shows the state before fixing a lid | cover to a main body after accommodating a radiation source. The 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 in alignment with the axis line in the state after the paraffin of the radiation source storage container of FIG. 1 fuse | melted. The VV sectional view taken on the line of the radiation source storage container of FIG. It is a graph which shows the performance of the paraffin used for the radiation source storage container of FIG. 1, a vertical axis | shaft shows expansion force and a horizontal axis shows the holding time of a heating state.

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

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

  The radiation source container C is a substantially columnar radiation source container 2 that houses the radiation source 1, an annular shielding plate 3 that is fixed to the upper surface of the radiation source container 2, and a bottom that has an opening above it. A cylindrical main body 4 that can accommodate the radiation source container 2 and the shielding plate 3 therein, a substantially columnar lid 5 that can be fitted into an opening of the main body 4, and a plurality of parts provided below the main body 4. Leg portions 6 and a plurality of suspension pieces 7 provided above the main body 4.

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

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

  The 1st accommodating member 2a, the 3rd accommodating member 2c, the 4th accommodating member 2d, and the 6th accommodating member 2f are formed with the 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.

  To the annular third housing member 2c, the flange of the bottomed tubular fourth housing member 2d provided with a flange at the upper end edge and the annular shielding plate 3 are fixed by bolts from the upper surface side.

  After accommodating the radiation source 1, the columnar fifth accommodating member 2e is inserted into the bottomed cylindrical fourth accommodating member 2d with the flange. Here, when the dimension of the 5th accommodating member 2e is accommodated in the 4th accommodating member 2d with the radiation source 1, it is the upper end surface of the 5th accommodating member 2e, and the upper surface of the flange part of the 4th accommodating member 2d. The length is such that approximately matches. Therefore, the upper end surface of the fifth housing member 2e is in contact with the lower surface of the disk-like sixth housing member 2f placed on the flange of the fourth housing member 2d.

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

  The shielding plate 3 is made of paraffin. The shielding plate 3 shields the radiation source container C as a whole by filling a gap formed between the lid 5 and the radiation source container 2 with a bolt or the like protruding above the radiation source container 2. Improves performance. When the gap between the lid 5 and the radiation source container 2 is very narrow, the shielding plate 3 may be omitted.

  The main body 4 is inserted into the bottomed cylindrical first main body member 4a having an opening on the upper side and the first main body member 4a so that the upper end surfaces thereof substantially coincide with each other, 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 equal to the 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 with the steel plate which is a lining material. The 2nd main body member 4b is formed with the material which shields the kind of radiation different from a lead material, specifically, paraffin (2nd shielding material).

  The bottom surface of the first body member 4a is configured as a curved surface that is curved so as to protrude outward in the axial direction. This is because the bottom surface on which the load concentrates is a curved surface, so that the pressure applied by the second body member 4b due to thermal expansion or the like is distributed to the bottom surface to prevent deformation / breakage on the bottom surface.

  Since the bottom surface of the first main body member 4a is a curved surface, the radiation source container C cannot stand by itself with the bottom surface of the main body 4 grounded. Therefore, the radiation source container C is configured to be able to stand on its own via a plurality of legs 6 provided in the lower part. Each of the leg portions 6 is provided with a hole, and a fixing wire or the like can be locked in the hole.

  In addition, when the thickness of the steel plate is sufficient, the bottom surface may have a flat shape as long as deformation / breakage on the bottom surface of the first main body member 4a can be sufficiently prevented by a separate means.

  The second main body member 4b is connected to the bottom 4b1 having a thickness from the bottom surface of the first main body member 4a to the lower surface of the radiation source container 2, and the bottom 4b1, and the second main body member 4b is fitted into the radiation source container 2. The first cylindrical portion 4b2 and the second cylindrical portion 4b3 are provided continuously above the first cylindrical portion 4b2, have a larger inner diameter than the first cylindrical portion 4b2, and are fitted with the lid 5.

  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 main body member 4 d is welded to the outer peripheral edge of the annular third housing member 2 c of the radiation source housing 2. That is, in the radiation source container C, a sealed space is formed between the main body 4 and the radiation source container 2, and a second body member 4b formed of the second shielding material is disposed in the sealed space. It has become.

  As shown in FIG. 3, a plurality of first protrusions 4 b 4 (first protrusions) projecting radially outward and extending along the axis are formed at equal intervals on the outer peripheral surface of the second main body member 4 b. Is provided. A predetermined gap is formed between the second main body member 4b and the first main body member 4a by the first protrusions 4b4.

  Thereby, even if the 2nd main body member 4b (2nd shielding material) inside the main body 4 thermally expands, the raise of the internal pressure inside the main body 4 is suppressed. As a result, the first main body member 4a, the third main body member 4c, the fourth main body member 4d, and the lid 5 fitted into the main 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 on the upper side, and a columnar first lid inserted so that the upper end surface thereof substantially coincides with the first lid member 5a. 2 lid members 5b, a disc-shaped third lid member 5c mounted on the upper end surface of the first lid member 5a and the upper end surface of the second lid member 5b, and attached to the upper surface of the third lid member 5c. It comprises a plurality of eyenuts 5d.

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

  The upper end edge of the bottomed cylindrical first lid member 5a is welded to the lower surface of the disk-shaped third lid member 5c. That is, the lid 5 has a structure in which a sealed 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 disposed in the sealed space. It has become.

  As shown in FIG. 3, a plurality of second protrusions 5 b 1 (second protrusions) protruding outward in the radial direction and extending along the axis are formed at equal intervals on the outer peripheral surface of the second lid member 5 b. Is provided. A predetermined gap is formed between the second lid member 5b and the first lid member 5a by the second protrusion 5b1.

  Thereby, even if the 2nd cover member 5b (2nd shielding material) inside the lid | cover 5 thermally expands, the raise of the internal pressure in the inside of the lid | cover 5 is suppressed. As a result, the first lid member 5a, the third lid member 5c, and the main body 4 into which the lid 5 is fitted are prevented from being deformed or damaged.

  By the way, as shown in FIG.1 and FIG.2, the minimum outer diameter (namely, the outer diameter of the part except 2nd protrusion 5b1) of the 2nd cover member 5b is formed with the lead material of the radiation source container 2. As shown in FIG. It is configured to be larger than the maximum outer diameter (that is, the outer diameter of the second housing member 2b) of the portion that is formed.

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

  Thereby, when the lid 5 is fitted to the main body 4, the second shielding is also provided between the radiation source container 2 and the gap between the first lid member 5 a and the second lid member 5 b of the lid 5. Paraffin, which is a material, is present.

  That is, the radiation source container 2 that surrounds the radiation source 1 with lead, which is the first shielding material, is surrounded by paraffin, which is the second shielding material having a sufficient thickness without any gap in all directions. . As a result, the radiation source storage container C can exhibit a sufficient shielding performance even though the gap is provided in the lid 5.

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

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

  As the paraffin for shielding neutron rays, a paraffin having a melting point of 88 degrees Celsius is used. For such paraffin, based on the technical standard (temperature range of -40 degrees Celsius to 70 degrees Celsius) for A-type transports stipulated in the "Regulation for Enforcement of Laws on Prevention of Radiation Hazards due to Radioisotopes" In performance tests, it has been demonstrated that although thermal expansion occurs, no cracks or breakage occur.

  By the way, the performance test is usually performed using a sample formed only of a paraffin material, and is surrounded and sealed with a steel material as a lining material, like the radiation source container C of the present embodiment. This is not done with a fresh sample. Therefore, in an actual product, it is considered preferable to sufficiently consider the influence of thermal expansion of the paraffin material (that is, increase in internal pressure) that does not cause 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 protrusions 4 b 4 (first protrusions) protruding outward in the radial direction on the outer peripheral surface of the second main body member 4 b. Part) are provided at equal intervals, and a predetermined gap is formed between the second main body member 4b and the first main body member 4a by the first protrusions 4b4.

  In addition, a plurality of second protrusions 5b1 (second protrusions) that protrude radially outward are provided at equal intervals on the outer peripheral surface of the second lid member 5b, and the second protrusions 5b1 provide the first protrusions 5b1. A predetermined gap is formed between the two lid members 5b and the first lid member 5a.

  In the radiation source container C in which these voids are formed, even if heat more than expected is applied to the radiation source container C, the paraffin simply moves so as to fill the voids. The internal pressure is prevented from greatly increasing due to thermal expansion.

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

  As shown in FIGS. 4 and 5, in the radiation source container C, the paraffin is in a molten state in a state where the radiation source container 2 and the lid 5 are installed on the main body 4, and the first main body member 4 a. When the fluid flows so as to fill the gap between the first body member 4b and the second body member 4b, the upper surface of the second body member 4b (specifically, the second cylindrical 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.

  Thereby, even if the paraffin is melted so that the fluidity of the paraffin constituting the second main body member 4b becomes very high (that is, regardless of the state of the second main body member 4b), the radiation source The state where the periphery of the container 2 is surrounded by the lead material which is the first shielding material and the paraffin which is the second shielding material having a sufficient thickness is maintained, and the shielding performance is maintained.

  In addition, when using resin etc. with high melting | fusing point as a 2nd shielding material, possibility that a 2nd shielding material will flow so much will become low. In such a case, when the volume of the second main body member 4 b flows, the upper surface of the second main body member 4 b after the flow is not necessarily maintained at a position higher than the upper surface of the radiation source container 2. It is not necessary to set a large volume.

  Here, the size of the gap formed 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 breakage of the first main body member 4a in a plane crossing the axis of the first main body member 4a. It is comprised so that the ratio with respect to an area may be 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 a plane crossing the axis of the first lid member 5a. It is configured to be 8% or more.

  As described above, when the void ratio is 8% or more, it is experimentally possible to effectively suppress the increase in internal pressure while suppressing the thickness of the body of the second main body member 4b or the second lid member 5b. Has been found. Details of the experiment will be described below.

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

  As the expansion force measuring device, a cylinder tube in 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 were used. As the sample, a substantially columnar one provided with a buffer space (void) calculated from the volume of the paraffin material on the outer peripheral portion was used. There were three buffer space ratios: 0%, 5%, and 8%.

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

  A graph of the experimental results related to the above experiment is shown in FIG. In FIG. 6, the vertical axis represents the expansion force, and the horizontal axis represents the heating time.

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

  Further, when comparing the expansion force when each sample is held for 40 minutes in an environment of 70 degrees Celsius, the sample with a buffer space ratio of 0% is about 935 N, the sample with 5% is about 580 N, and the sample with 8% is about 315 N. Expansion force was generated. When this expansion force is converted into pressure, a pressure of about 0.59 MPa is generated for a sample with a buffer space ratio of 0%, a pressure of about 0.36 MPa for a sample of 5%, and a pressure of about 0.20 MPa 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 calculating 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 having a buffer space ratio of 0% is 1, the sample of 5% is about 0.61, and the sample of 8% is about 0.34. It can be inferred that the same performance as that of the 0% sample can be obtained with the thickness.

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

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

  For example, in the said embodiment, lead is employ | adopted as a 1st shielding material and paraffin is employ | adopted as a 2nd shielding material. However, the shielding material of the present invention is not limited to these, and the two shielding materials only need to shield different types of radiation.

  Moreover, in the said embodiment, the space | gap is formed between the 1st main body member 4a and the 2nd main body member 4b by the 1st protrusion part 4b4, and the 1st cover member 5a is formed by the 2nd protrusion part 5b1. And a second lid member 5b. However, the 1st protrusion part and 2nd protrusion part of this invention should just protrude toward the radial direction outer side, and do not need to extend along an axis line.

  For example, a plurality of protrusions may be arranged at intervals along the axis to form a line, and a plurality of the lines may be arranged in the circumferential direction. Moreover, you may arrange | position a protrusion one by one in the circumferential direction.

  Moreover, in the said embodiment, the space | gap formed between the 1st main body member 4a of the main body 4 and the 2nd main body member 4b is the 1st main body member 4a in the plane which crosses the axis line of the 1st main body member 4a. It is comprised so that the ratio with respect to a cross-sectional area may be 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 a plane crossing the axis of the first lid member 5a. It is configured to be 8% or more.

  However, the gap in the present invention does not necessarily have to be 8% or more in both the main body and the lid, and the size may be appropriately changed according to the shapes of the main body and the lid.

DESCRIPTION OF SYMBOLS 1 ... Radiation source, 2 ... Radiation source accommodating body, 2a ... 1st accommodating member, 2b ... 2nd accommodating member, 2c ... 3rd accommodating member, 2d ... 4th accommodating member, 2e ... 5th accommodating member, 2f ... 1st 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 ... 1st 1 projecting portion (first projecting portion), 4c... 3rd main body member, 4d... 4th main body member, 5... Lid, 5a ... 1st lid member, 5b. (2nd protrusion part) 5c ... 3rd cover member, 5d ... Eye nut, 6 ... Leg part, 7 ... Hanging piece, C ... Radiation source storage container.

Claims (4)

A bottomed cylindrical main body having an opening above and a lid fitted to the opening of the main body, and a radiation source is provided in the first shielding material that shields predetermined radiation inside the main body A radiation source storage container for storing an embedded columnar radiation source container,
The main body is formed of a bottomed cylindrical first body member and a second shielding material that shields different types of radiation from the first shielding material, and has a bottomed structure disposed inside the first body member. A cylindrical second body member,
The second main body member includes a bottom portion having a predetermined thickness, a first tubular portion into which the radiation source container continuously provided above the bottom portion is fitted, and a continuous portion above the first tubular portion. An inner diameter larger than that of the first tubular portion, and a second tubular portion 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 protrude outward in the radial direction and to form a predetermined gap between the second main body member and the first main body member. And
The lid includes a bottomed cylindrical 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 outward in the radial direction and form a predetermined gap between the second lid member and the first lid member. And
The radiation source container according to claim 1, wherein a minimum outer diameter of the second lid member is configured to be larger than a maximum outer diameter of a portion formed of the first shielding material of the radiation source container. The radiation source container according to claim 1,
The ratio of the gap between the first main body member and the second main body member to the cross-sectional area of the first main body member in the plane crossing the axis of the first main body member, and the plane crossing the axis of the first lid member At least one of the ratios of the gaps between the first lid member and the second lid member in the cross-sectional area of the first lid member is 8% or more. In the radiation source container according to claim 1 or 2,
The radiation source container, wherein the second shielding material is paraffin or a thermoplastic resin. The radiation source container according to claim 3,
In a state where the radiation source container and the lid are installed with respect to 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. When the fluid flows, the volume of the second body member is set so that the upper surface of the second body member after the fluid flow is maintained at a position higher than the upper surface of the radiation source container. A radiation source container.