JP3132209U - Transport and storage container for radiation source - Google Patents

Abstract

An object of the present invention is to provide a neutron beam which is cheaper and more stable than the conventional regulation regulation value, because the radiation dose rate leaked from the packing surface during transportation of a radiation source enclosing a moisture density meter or a minute radioactive isotope of the moisture meter A transport container capable of shielding is provided.
A neutron beam attenuation material is paraffin and cast into a sphere with a foamed resin mold. At that time, a heavy metal sphere which is a gamma ray attenuating material is cast into paraffin. The foamed resin mold is used as a container cushioning material and a paraffin reinforcing material without releasing the mold.
[Selection] Figure 1

Description

  The present invention relates to a moisture density meter using a radioisotope and a container used for transporting and storing a radiation source of the moisture meter.

  Moisture meters and moisture meters that use radiation are used by incorporating a source rod in which a radioactive isotope that emits neutrons and gamma rays is enclosed in a stainless steel rod into the instrument body. The radioisotope used in the instrument generally has a radioactivity of 3.7 MBq or less. Conventionally (before May 2005), it was stipulated that a micro-radiation source of 3.7 MBq or less should not be regarded as a radioisotope in the laws and regulations related to radioisotopes. However, due to the amendment of laws and regulations that became applicable after June 2005, the radiation dose rate regulation value on the surface of the transportation packing of the source rod will be increased more securely than before and reliably ensured. A shielding container that can be used is needed.

  As radiation shielding materials, polyethylene, paraffin and water against neutron radiation, and heavy metals such as lead and tungsten alloys are widely used for shielding gamma rays. However, polyethylene is generally used for the neutron shielding material of the portable container due to strength and handling problems, but polyethylene requires a lot of material and molding.

  As described above, the leakage radiation rate on the packing surface when the source rod is transported is attenuated to an appropriate value, and manufacturing a portable radiation shielding container requires a lot of costs. The present invention aims to solve the above-mentioned problems by realizing a portable source rod transport container that is inexpensive and attenuates the leakage dose rate to an appropriate value, and that can also be used as a source rod storage container. It is.

  The present invention uses paraffin as a neutron beam attenuating material and uses a foamed resin as a paraffin mold. Assume that a heavy metal sphere, which is a gamma ray attenuating material, with a source rod insertion guide placed in the center and cast with paraffin. The foamed resin mold is used as a reinforcing material for paraffin and a cushioning material for the transport container without releasing the mold after casting the paraffin.

  It is legal to set the outer dimensions of the foamed resin mold so that the outer surface of the foamed resin mold is the packaging surface, and the leakage dose rate on the packaging surface specified by law is less than or equal to the packaging surface. It becomes a transport container and also a daily source rod storage container.

  Paraffin has a function equivalent to that of polyethylene as a neutron beam attenuating material and has a melting point of about 50 ° C., and a foamed resin has sufficient heat resistance as a mold.

  As described above, by using paraffin having a low melting point as the neutron beam attenuating material, the mold of paraffin can be made of foamed resin, and the sphere can be easily molded and the cost can be greatly reduced. In addition, the foamed mold is used as it is to reinforce the cushioning material and paraffin without releasing the mold, so there is no deformation during transportation, and the exterior of the light packaging box makes it a transport container and an everyday storage container. is there.

  Furthermore, since the foaming mold and the paraffin are used as a cushioning material without releasing, there is almost no generation of waste.

  In order to reduce the weight of the container as much as possible without impairing the shielding effect, the shielding material is made into a sphere, and the basic shape is to store the radioisotope in the center.

  In order to cast a paraffin sphere, a foamed resin is used as a mold, and a sphere made of heavy metal, which is a gamma ray attenuating material, is placed in the center of the sphere, and a guide hole for inserting a source rod is inserted into the sphere. Set up a tube. The molten paraffin is filled and solidified between the heavy metal sphere and the mold, and the foamed resin mold is placed in the light box as it is as a cushioning material and a paraffin reinforcement without being released from the mold.

  Hereinafter, embodiments of the present invention will be described with reference to FIGS. The gamma-ray attenuation material sphere 1 is manufactured by casting heavy metal such as lead. In the heavy metal casting, the source rod insertion tube 5 is cast. A polyethylene support 7 is set up on a foamed resin mold (lower mold) 4, and a gamma ray attenuation material sphere 1 is placed on the polyethylene support 7 and covered with a foamed resin mold (upper mold) 3 provided with a paraffin inlet 6. . Apply adhesive to the upper and lower mating surfaces of the foamed resin mold. After the upper and lower molds are fixed, a small-diameter hole for venting air is appropriately provided on the upper outer surface of the mold and the hollow portion inside, and heated and melted paraffin is injected to the upper surface of the mold.

  After the paraffin has solidified and cooled to room temperature, it is enclosed in a foamed resin mold, packed in an outer box 9, covered with an outer lid 10, and the source rod is inserted into the source rod insertion tube 5 and plugged with a cap 8. 11 is applied.

  It is a front sectional view of a transportation and storage container showing an embodiment of the present invention.   The AA sectional view taken on the line in FIG. 1 of the container is shown.

Explanation of symbols

1 Gamma ray attenuation material sphere 2 Paraffin sphere 3 Foamed resin mold (upper mold)
4 Foamed resin mold (lower mold)
5 Source rod insertion tube 6 Paraffin inlet 7 Polyethylene prop 8 Cap 9 Outer box 10 Outer box cover 11 Tablets

Claims (1)

  A radiation source transport container and a radiation source storage container characterized in that paraffin is cast into a foamed resin mold, and the foamed resin mold is not released even after casting, and is used as a cushioning material and a paraffin reinforcing material.

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