JP2003185785A - Radioactive material containment vessel and radioactive material containment vessel storage facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the cost of constructing a storage facility by calculating the thickness needed for a shield member of the storage facility by use of neutron and gamma doses on the surface of a radioactive material containment vessel. <P>SOLUTION: The thickness of the ceiling or sidewall of a storage building is calculated using neutron and gamma doses on the surface of the radioactive material containment vessel so that dose rates at the boundary of the site of the storage building are not more than limit values and so that the thickness of the shield member shielding radiation from the surface of the radioactive material containment vessel is small for the outside of the storage building. The storing building is constructed using the result of the calculation. Because the thickness of the shield member of the storage building is determined while taking into consideration the neutron and gamma doses on the surface of the radioactive material containment vessel, the thickness of the shield member can be optimized compared with conventional methods and the cost of constructing the storage facility can be reduced. <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 container for accommodating radioactive substances that generate heat such as high-level radioactive waste and spent fuel generated from a nuclear power plant, and a radioactive substance storage container storage facility for storing the container. It is related to.

[0002]

BACKGROUND OF THE INVENTION Spent fuel assemblies generated from nuclear power plants are reprocessed to recover reusable nuclear fuel materials such as uranium and plutonium, but the high level radioactive waste generated at this time is Vitrified. Since this radioactive waste vitrified body generates decay heat, it must be stored while being cooled until the calorific value becomes small and disposal becomes possible. The spent fuel assemblies are stored in the storage pool in the nuclear power plant until they are reprocessed. Construction of a new storage facility that can store is desired. In this storage facility, storage in radioactive substance storage containers having shielding performance is considered from the viewpoint of cost, long-term safety, and track record.

The facility for storing this radioactive substance storage container is required to maintain the shielding performance of gamma rays and neutron rays from the radioactive substance storage container and to have sufficient structural strength.

Examples of conventional radioactive substance storage container storage facilities include Japanese Patent Laid-Open Nos. 9-26497 and 2000-2000.
There are storage facilities described in JP-A-180586 and JP-A-9-113679.

In the radioactive substance storage container storage facility disclosed in Japanese Unexamined Patent Publication No. 9-26497, the ceiling portion of the storage building is provided with a removable hatch having shielding performance. A gate-type crane for transporting radioactive material storage containers is provided on the hatch, and the structure is covered with a lightweight roof that does not have shielding ability.

Further, in the radioactive substance storage container storage facility disclosed in Japanese Patent Laid-Open No. 2000-180586 and Japanese Patent Laid-Open No. 9-113679, a bridge-type transfer crane is installed above the ceiling of the storage building, and the ceiling of the storage building is installed. Is an openable and closable structure for loading and unloading radioactive material storage containers into the storage building. Radiation from the radioactive material storage container is shielded by the wall or ceiling of the storage room with sufficient thickness.

[0007]

In each of the conventional radioactive substance storage container storage facilities described above, an opening / closing shield member is provided on the ceiling of the storage room for storing the radioactive substance storage container. The material of this shield is not specified, but since concrete is usually used, the thickness is 0.
A thickness of 5 m to 2 m is required. Therefore, the amount of materials required to construct the storage building becomes enormous. As for the radioactive material storage container, the dose rate needs to be reduced to a level at which the worker can work around the container, so the amount of metal and neutron shield required for manufacturing the container becomes enormous. If the amount of these members becomes enormous, the construction cost of the storage building and the production cost of the radioactive substance storage container will be increased as they are.

Conventionally, since the shielding thickness required for the radioactive substance storage container and the shielding thickness required for the storage building of the radioactive substance storage container have been designed separately, the amount and cost of each member are not necessarily small. It wasn't

The object of the present invention is to use the ratio of the neutron dose and the gamma dose on the surface of the radioactive substance storage container, the value of the neutron dose and the gamma dose on the surface of the container, or the neutron dose and the gamma dose of the radioactive substance to be stored. Then, the thickness of the shielding member that shields the radiation from the container surface to the wall of the radioactive substance storage container storage building and the outside of the storage building is calculated and manufactured to construct the radioactive substance storage container storage facility. It is to reduce the cost.

Another object of the present invention is to store a radioactive substance storage container based on data on the thickness and elemental composition of a shielding member that shields the radiation from the surface of the radioactive substance storage container to the outside of the radioactive substance storage container storage building. It is intended to reduce the manufacturing cost of the radioactive material storage container by calculating and manufacturing the thickness of the metal and neutron shield necessary for manufacturing.

Another object of the present invention is the ratio of the neutron dose to the gamma dose on the surface of the radioactive substance container, the value of the neutron dose and the gamma dose on the surface of the container, or the neutron dose and the gamma dose of the radioactive substance to be stored. By using, to calculate the thickness of the metal and neutron shield required for the radioactive material storage container, and the thickness required for the shielding member that shields the radiation from the container surface to the outside of the storage building , To reduce both the manufacturing cost of radioactive material storage containers and the construction cost of radioactive material storage container storage facilities.

[0012]

The features of the invention of claim 1 for attaining the above object are that the radiation dose on the surface of the radioactive substance storage container and the value of the ratio of the neutron dose to the gamma dose, or the container surface. The neutron dose and gamma dose of the radioactive substance, or the neutron dose and gamma dose of the radioactive substance to be stored, and the dose rate at the site boundary of the radioactive substance storage container storage building is below the limit value and to the outside of the storage building. The thickness of the shielding member that shields the radiation from the container surface to the outside of the storage building so that the thickness of the shielding member that shields the radiation from the surface of the radioactive substance storage container is below a preset limit value. Is calculated and the calculated result is used to construct a radioactive substance storage container storage building. Since the neutron dose and gamma dose on the surface of the radioactive material storage container are taken into consideration, the thickness of the shielding member that shields the radiation from the surface of the radioactive material storage container to the outside of the storage building is determined. The thickness of the storage facility can be optimized, and the construction cost of the storage facility can be reduced.

The feature of the invention of claim 2 that achieves the above-mentioned other object is that the thickness and the elemental composition of the shielding member for shielding the radiation from the container surface to the outside of the building that stores the radioactive substance storage container are Using the values, the dose rate at the site boundary of the storage building is below the limit value, and the total weight of the container is below the preset limit value, each thickness of the metal and neutron shield of the container Is calculated and the radioactive substance storage container is manufactured using the calculated result. As a result, the weight of the container can be reduced, which in turn can reduce the manufacturing cost of the container.

In order to achieve the above-mentioned other object, the feature of the invention of claim 3 is that the thickness and the elemental composition of the shielding member for shielding the radiation from the container surface to the outside of the building storing the radioactive substance storage container are controlled. Using the value, the dose rate at the site boundary of the storage building is below the limit value, and the amount of the neutron shield in the container is below the preset limit value, the metal of the container and the neutron shield Each thickness is calculated, and the radioactive substance storage container is manufactured using the calculation result. As a result, it is possible to reduce the amount of neutron shields, which have relatively high material costs. Moreover, since the thickness of the neutron shield having poor heat transfer performance is reduced, the temperature of the radioactive substance in the container can be reduced.

In order to achieve the above-mentioned other object, the feature of the invention of claim 4 is that the thickness and the elemental composition of the shielding member for shielding the radiation from the container surface to the outside of the building storing the radioactive substance storage container Using the value, the dose rate at the site boundary of the storage building is below the limit value, and the dose rate on the container surface is below the preset limit value, so that the thickness of each metal and neutron shield of the container The purpose is to manufacture a container for radioactive material using the calculated result. As a result, the radiation dose inside the storage building is reduced, and the radiation dose to workers can be reduced.

A feature of the invention of claim 5 for achieving the above-mentioned other object is that the ratio of the radiation dose to the neutron dose and the gamma dose on the surface of the radioactive substance storage container or the neutron dose on the surface of the radioactive substance storage container and Using the gamma dose value or the neutron dose and gamma dose of radioactive material to be stored, the dose rate at the site boundary of the storage building is below the limit value, and the thickness of the radioactive material storage container and the outside of the storage building are The metal thickness of the container and the neutron shield, and the outside of the storage building so that the sum of the thicknesses of the shielding members that shield the radiation from the container surface is less than or equal to the preset limit value. The thickness of the shielding member that shields the radiation from the container surface is calculated, and the calculated result is used to fabricate a radioactive substance storage container and a radioactive substance storage container storage facility. Thereby, the amount of material required for manufacturing the radioactive substance storage container and constructing the storage facility can be reduced.

The feature of the invention of claim 6 for achieving the above-mentioned other object is that the ratio of the radiation dose to the neutron dose and the gamma dose on the surface of the radioactive substance storage container or the neutron dose on the surface of the radioactive substance storage container and Using the gamma dose value or the neutron dose and gamma dose of radioactive material to be stored, the dose rate at the site boundary of the storage building is below the limit value, and the material cost of the container metal and neutron shield and the storage building The thickness of the metal and neutron shield of the container and the thickness of the storage building so that the sum of the material costs of the shielding members that shield the radiation from the surface of the container to the outside of the Calculate the thickness of the shielding member that shields the radiation from the container surface to the outside, and use the calculation result to fabricate a radioactive substance storage container and a radioactive substance storage container storage facility. In the door. Thereby, the manufacturing cost of the radioactive substance storage container and the construction cost of the storage facility can be reduced.

[0018]

DESCRIPTION OF THE PREFERRED EMBODIMENTS (Embodiment 1) A preferred embodiment of the present invention will be described with reference to FIGS. This embodiment relates to claim 1, and shows a method of reducing the thickness of the shield provided in the radioactive substance storage container storage facility according to the radioactive substance storage container to be stored.

As shown in FIG. 2, the storage facility shown in this embodiment contains a radioactive substance 2 inside, and a metal part 3 which mainly serves to shield gamma rays from the radioactive substance,
It is a facility for storing a radioactive substance storage container 1 which is located outside thereof and mainly comprises a neutron shield 4 which plays a role of shielding neutron rays from the radioactive substance 2. Possible radioactive substances 2 to be stored in such a radioactive substance storage container 1 include a spent nuclear fuel assembly generated from a nuclear power plant, or a high-level radioactive waste liquid vitrified body,
Alternatively, a container in which waste having a high radioactivity level is sealed may be used.

Neutron rays and gamma rays generated from the radioactive substance 2 are shielded by the radioactive substance storage container 1 to a level at which an operator can access the container surface without radiation protective clothing. Especially when this container also serves as a transport container, the dose rate on the surface of the container is 2 mSv / hour, and the dose rate is 1 from the surface of the container.
There is a limit value of 100 μSv / hour for the dose rate at a distance of m. However, at the site boundary 6 of the storage facility, there is a limit value of the dose rate of 50 μSv / year at the maximum. To meet this limit value, between the radioactive substance storage container 1 and the site boundary 6 of the storage facility. , It is necessary to add an additional radiation shield. Therefore, by thickening the wall 5 of the storage building of the radioactive substance storage container 1, the radiation dose at the site boundary 6 is reduced below the limit value. Concrete is mainly used for the wall 5 of the storage building. Since the thickness of the wall 5 of the storage building greatly affects the amount of concrete required for the construction of the storage building, it is possible to reduce the construction cost of the storage facility by making the wall 5 of the storage building as thin as possible. .

As described above, the radioactive substance storage container 1 emits two types of radiation, gamma rays and neutron rays.
Radiation that reaches the site boundary 6 of the storage facility includes gamma rays 7 and neutron rays 8 that directly reach from the radioactive substance storage container 1.
In addition, gamma rays 9 and neutron rays 10 by skyshine, which are scattered and reached by gas molecules and dust in the sky
Therefore, the sum of the dose rates of each radiation is the dose rate at the site boundary 6 of the storage facility.

The shielding effect of the wall 5 of the storage building greatly differs depending on the type of radiation. Therefore, for example, the dose rate at a position 1 m away from the surface of the radioactive substance storage container 1 is 1
Even if it is 00 μSv / hour, the wall thickness of the storage building 5 is necessary to keep the dose rate at the site boundary 6 of the storage facility below the limit value, depending on whether the dose rate is due to neutron rays or gamma rays. Will be different. Fig. 4 shows the wall 5 thickness of the storage building necessary for the dose rate at the site boundary 6 of the storage facility to be less than the limit value with respect to the ratio of the dose rate of neutron rays to gamma rays on the surface of the radioactive substance storage container 1. An example of the result of calculating the relationship between the heights is shown. Thus, it can be seen that even if the dose rate on the surface of the container is the same, the thickness required for the wall 5 of the storage building greatly changes depending on the ratio of neutron rays to gamma rays.

Therefore, the construction cost of the storage building can be reduced by taking into consideration the ratio of the dose rates of neutron rays and gamma rays on the surface of the radioactive substance storage container 1 and determining the minimum thickness of the wall 5 of the storage building. It can be greatly reduced. FIG. 1 shows an example of a method for obtaining the thickness of the wall 5 of the storage building. First, based on the ratio of the radiation dose on the surface of the radioactive material storage container 1 to the dose rate of neutron rays and gamma rays, or the radiation dose of each of the neutron rays and gamma rays on the surface of the radioactive material storage container 1, the wall of the storage building Assuming a thickness of 5, the dose rate at the site boundary 6 of the storage facility is calculated from the gamma ray 7 and the neutron beam 8 that directly reach the site boundary 6 of the storage facility, and the gamma ray 9 and the neutron beam 10 due to Skyshine. If this calculated value is larger than the limit value, increase the wall 5 thickness of the storage building assumed before calculation, and if the calculated value is significantly smaller than the limit value, assume before calculation. Wall 5 of the storage building
The thickness is reduced and the dose rate at site boundary 6 of the storage facility is calculated again. Then, when the calculated value and the limit value become equal, the wall 5 thickness of the storage building assumed at that time becomes the minimum necessary storage building wall 5 thickness. Actually, the thickness of the storage building wall 5 is determined so as to be a value slightly smaller than the limit value in consideration of the calculation error.

The above example is the case where the wall 5 of the storage building plays a role of shielding radiation, but as shown in FIG. 3, the place for storing the radioactive substance storage container 1 and the radioactive substance storage container 1 are A plug 12 that can be opened and closed is provided between the crane 11 area for moving and the plug 12
Plays a role of radiation shielding, and in the case of a facility in which the warehouse 13 above it has no radiation shielding ability, the thickness of the plug 12 influences the dose at the site boundary. The required minimum thickness of the plug 12 is obtained by the same method as in FIG. In the case of FIG. 3, gamma rays 7 and neutron rays 8 that directly reach the site boundary 6 of the storage facility are calculated using the thickness of the wall 5 of the storage building, and gamma rays 9 and neutron rays 10 by skyshine are calculated. , Plug 1
Two thicknesses are used for the calculation, and the minimum necessary thickness for each is calculated.

When the dose rate on the surface of the radioactive substance storage container is unknown, the container and the building are collectively calculated using the radiation dose data of the gamma ray and neutron ray of the radioactive substance as shown in FIG. It is also possible.

(Embodiment 2) Another embodiment (Embodiment 2) of the present invention will be described with reference to FIGS. 2 and 6 to 10. This embodiment relates to claims 2 to 4, and the storage facility is as shown in Fig. 2. In this embodiment, the wall thickness of the storage building of the radioactive substance storage container is predetermined. In this case, a method for optimizing the thickness of the radioactive substance storage container is shown.

FIG. 6 shows an example of a method for obtaining the optimum values of the respective thicknesses of the metal part 3 and the neutron shield part 4 of the container so that the total weight of the radioactive substance storage container 1 becomes small. First, the respective thicknesses of the metal part 3 and the neutron shield part 4 of the radioactive substance storage container 1 are determined so as to satisfy the dose rate limit values at the surface of the radioactive substance storage container 1 and at a position 1 m away from the surface. Assuming the thicknesses of the metal part 3 and the neutron shield part 4, calculate the dose rate at the surface of the container 1 and at a position 1 m away from the surface, and one of them is equal to the limit value and the other is below the limit value. The thicknesses of the metal part 3 and the neutron shield part 4 are calculated as follows.

Next, using the thickness of the wall 5 of the storage building, the dose rate at the site boundary 6 of the storage facility is calculated as in the first embodiment. Here, when the calculated value exceeds the limit value, the thickness of the wall 5 of the storage building is predetermined and cannot be changed. Therefore, the thicknesses of the metal part 3 and the neutron shield part 4 of the radioactive substance storage container 1 are changed again. Change to obtain another combination of the thickness of the metal part 3 and the neutron shield part 4 that satisfies the dose rate limit value at the surface of the container 1 and at a position 1 m away from the surface, and again, the site boundary of the storage facility Calculate the dose rate at 6. By repeating this calculation one after another, the thickness of the metal part 3 and the neutron shield part 4 that meet all the dose rate limits at the container 1 surface and at a position 1 m away from the surface and at the site boundary 6 Ask for a combination.

Finally, if the combination with the smallest total weight of the radioactive substance storage container 1 is found out of the combinations, it is the metal part 3 of the radioactive substance storage container 1 with respect to the total weight of the radioactive substance storage container 1. And the neutron shield part 4 have the optimum thickness values.

Before using the above method, the metal portion 3 and the neutron shield portion of the radioactive substance storage container 1 satisfying the limits of the dose rate at the surface of the radioactive substance storage container 1 and at a position 1 m away from the surface. It is convenient to find the relationship between the thicknesses of 4 above. FIG. 7 shows the container thickness required to meet the dose rate limit value at the surface of the radioactive substance storage container 1 and at a position 1 m away from the surface, with respect to the ratio of the metal of the container to the thickness of the neutron shield. It is the schematic shown. If this figure is created in advance, the minimum thickness of the container that satisfies both limit values and the ratio of the thickness of the metal and the neutron shield at that time can be read from this figure. Thus, in order to reduce the thickness of the container, it is necessary to optimize the ratio of the thickness of the metal to the thickness of the neutron shield. However, when the thickness ratio of metal and neutron shield is changed, the ratio of gamma ray and neutron ray is different even if the dose rate at the surface of the container 1 and at a position 1 m away from the surface is the same, so the metal and neutron shield are shielded. Depending on the body thickness ratio, the dose at the site boundary 6 of the storage facility will be different.

As shown in FIG. 7, the surface of the container 1 or 1 m from the surface
When the relationship between the thickness of the metal portion 3 of the radioactive substance storage container 1 and the thickness of the neutron shield portion 4 that satisfies the limit value of the dose rate at the distant position is obtained in advance, the method shown in FIG. Can be rewritten as The dose ratio at the site boundary of the storage facility is calculated by changing the thickness ratio between the metal part 3 of the container 1 and the neutron shield 4, and the dose rate is below the limit value, and the total weight of the radioactive substance storage container 1 is calculated. If the combination that minimizes is obtained, the respective thicknesses of the metal part 3 and the neutron shield part 4 of the radioactive substance storage container 1 at that time become optimum thicknesses.

FIG. 9 shows a method for determining the thicknesses of the metal portion 3 and the neutron shield portion 4 of the radioactive substance storage container 1 so that the weight of the neutron shield is reduced. This is almost the same as the method shown in FIG. 8, and the judgment material in the part for selecting the thickness ratio of the metal 3 and the neutron shield 4 is
Only the weight of the neutron shield and the dose rate at the surface instead of the total weight are different.

FIG. 10 shows a method for obtaining the thicknesses of the metal portion 3 and the neutron shield portion 4 of the radioactive substance storage container 1 so that the dose rate on the surface of the radioactive substance storage container 1 becomes small. In this case, unlike FIGS. 8 and 9,
The container thickness that satisfies the site boundary dose of the storage facility is calculated first, and the one with the minimum dose rate on the surface of the container 1 is calculated.

(Embodiment 3) Another embodiment (Embodiment 3) of the present invention will be described with reference to FIGS. 2, 11, and 12.
This embodiment relates to claims 5 to 6,
The storage facility is as shown in FIG. 2, but this embodiment shows a method for optimizing both the thickness of the radioactive substance storage container and the wall thickness of the storage building.

FIG. 11 shows a method of obtaining the thickness of the radioactive substance storage container and the wall thickness of the storage building such that the sum of the thickness of the radioactive substance storage container and the wall thickness of the storage building becomes smaller. First, the thickness of the metal portion 3 of the storage container 1 and the neutron shield 4 such that the thickness of the storage container 1 is reduced while satisfying the dose rate limit value at the surface of the container 1 and at a position 1 m away from the surface. In the next step, the wall 5 thickness of the storage container is calculated so that the wall 5 thickness of the storage container becomes smaller while satisfying the dose rate limit value at the site boundary 6, and finally the radioactive Calculate the sum of the thickness of the substance storage container and the wall thickness of the storage building. Repeating this, if a condition that the sum of the thickness of the radioactive material storage container and the wall thickness of the storage building becomes small is found, the respective thicknesses of the metal part 3 and the neutron shield part 4 of the radioactive material storage container 1 at that time are found. , And the optimum value for the wall thickness of the storage building. As shown in FIG. 12,
It is effective to reduce the total construction cost of the radioactive material storage container and its storage building if the sum of the material costs is reduced, not the sum of the thickness of the radioactive material storage container and the wall thickness of the storage building. You can find the thickness of the container and the wall of the storage building.

[0036]

According to the invention of claim 1, the radiation dose on the surface of the radioactive substance storage container and the value of the ratio of the neutron dose and the gamma dose, or the value of the neutron dose and the gamma dose on the surface of the container, or Using the neutron dose and gamma dose of the radioactive material to be stored, the dose rate at the site boundary of the radioactive material storage container storage building is below the limit value, and the radiation from the surface of the radioactive material storage container is exposed to the outside of the storage building. Calculate the thickness of the shielding member that shields the radiation from the container surface to the outside of the storage building so that the thickness of the shielding member to be shielded is less than the preset limit value,
By constructing a radioactive substance storage container storage building using the calculated results, the ratio of neutron dose and gamma dose on the surface of the radioactive substance storage container is taken into consideration, and the radioactive substance storage container surface from the outside of the storage building is considered. Since the thickness of the shielding member that shields radiation is determined, it becomes possible to optimize the thickness of the shielding member as compared with the conventional case, and the construction cost of the storage facility can be reduced.

According to the invention of claim 2, the thickness of the shielding member for shielding the radiation from the container surface to the outside of the building for storing the radioactive substance storage container and the value of the elemental composition are used for the storage building. The dose rate at the site boundary is less than or equal to the limit value, and the total weight of the container is less than or equal to the preset limit value, and the thickness of the metal and neutron shield of the container is calculated, and the calculation result is By manufacturing a radioactive substance storage container using the container, the weight of the container can be reduced, and the manufacturing cost of the container can be reduced.

According to the third aspect of the present invention, the thickness of the shielding member for shielding the radiation from the container surface to the outside of the building for storing the radioactive substance storage container and the value of the elemental composition are used to determine the storage building. The dose rate at the site boundary is less than or equal to the limit value, and the amount of the neutron shield in the container is less than or equal to the preset limit value, and the thickness of each metal of the container and the neutron shield is calculated, By manufacturing the radioactive substance storage container using the calculation result, it is possible to reduce the amount of the neutron shield, which has a relatively high material cost. Moreover, since the thickness of the neutron shield having poor heat transfer performance is reduced, the temperature of the radioactive substance in the container can be reduced.

According to the invention of claim 4, the thickness of the shielding member for shielding the radiation from the container surface to the outside of the building for storing the radioactive substance storage container and the value of the elemental composition are used, and The dose rate at the site boundary is below the limit value, and the dose rate on the container surface is below the preset limit value, the thickness of the metal and neutron shield of the container is calculated, and the calculation result By manufacturing a radioactive substance storage container using, it is possible to reduce the radiation dose inside the storage building and to reduce the radiation dose to workers.

According to the invention of claim 5, the ratio of the radiation dose, the neutron dose and the gamma dose on the surface of the radioactive substance storage container, the value of the neutron dose and the gamma dose on the surface of the radioactive substance storage container, or the storage is performed. Using the neutron dose and gamma dose of radioactive material, the dose rate at the site boundary of the storage building is below the limit value, and the thickness of the radioactive material storage container and the radiation from the container surface to the outside of the storage building are shielded. The radiation from the container surface is shielded against the thickness of the metal and neutron shield of the container and the outside of the storage building so that the sum of the thicknesses of the shielding members to be used is less than the limit value given in advance. Calculate the thickness of the shielding material,
By manufacturing the radioactive substance storage container and the radioactive substance storage container storage facility using the calculation result, it is possible to reduce the amount of material required for manufacturing the container and constructing the storage facility.

According to the invention of claim 6, the ratio of the radiation dose, the neutron dose and the gamma dose on the surface of the radioactive substance storage container, the value of the neutron dose and the gamma dose on the surface of the radioactive substance storage container, or the value is stored. Using the neutron dose and gamma dose of radioactive materials, the dose rate at the site boundary of the storage building is below the limit value, and the material cost of the container metal and neutron shield and the outside of the storage building from the container surface The sum of the material costs of the shielding members that shield the radiation of
Calculate the thickness of the metal and neutron shield of the container, and the thickness of the shield member that shields the radiation from the container surface to the outside of the storage building so that it will be less than the given limit value. By manufacturing the radioactive substance storage container and the radioactive substance storage container storage facility using the calculation result, it is possible to reduce the manufacturing cost of the container and the construction cost of the storage facility.

[Brief description of drawings]

FIG. 1 is a flow chart showing a preferred embodiment of the present invention.

FIG. 2 is a schematic view of a radioactive substance storage container storage facility which is a preferred embodiment of the present invention.

FIG. 3 is a schematic diagram of a radioactive substance storage container storage facility according to a preferred embodiment of the present invention.

FIG. 4 is a diagram showing an example of the relationship between the dose rate ratio of neutron rays and gamma rays on the container surface and the required wall thickness of the storage building.

FIG. 5 is a flowchart showing a preferred embodiment of the present invention.

FIG. 6 is a flowchart showing a preferred embodiment of the present invention.

FIG. 7 is a view showing the container thickness required to satisfy the dose rate limit value at the container surface and at a position 1 m away from the surface, with respect to the ratio of the metal portion of the container and the thickness of the neutron shield. Is.

FIG. 8 is a flowchart showing a preferred embodiment of the present invention.

FIG. 9 is a flowchart showing a preferred embodiment of the present invention.

FIG. 10 is a flowchart showing a preferred embodiment of the present invention.

FIG. 11 is a flowchart showing a preferred embodiment of the present invention.

FIG. 12 is a flowchart showing a preferred embodiment of the present invention.

[Explanation of symbols]

1 ... Radioactive material storage container, 2 ... Radioactive material, 3 ... Radioactive material storage container metal part, 4 ... Radioactive material storage container neutron shield part, 5 ... Radioactive material storage container storage building wall, 6 ... Radioactive material storage Site boundary of container storage facility, 7 ...
Gamma rays that directly reach the site boundary 6, 8 ... Neutron rays that directly reach the site boundary 6, 9 ... Gamma ray skyshine,
10 ... Neutron beam skyshine, 11 ... Crane for transferring radioactive material storage container, 12 ... Plug, 13 ... Wall of storage building for radioactive material storage container (no shielding ability).

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Masafumi Oda             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Mamoru Kamoshida             2-12-1 Omika-cho, Hitachi-shi, Ibaraki Prefecture             Ceremony Company Hitachi, Ltd. (72) Inventor Hitoshi Shimizu             3-1-1 Sachimachi, Hitachi City, Ibaraki Prefecture Stock Association             Hitachi, Ltd. Nuclear Business Division

Claims (6)

[Claims] 1. Formed by a metal and a neutron shield,
In a storage building that stores a radioactive substance storage container in which a radioactive substance is hermetically stored, the ratio of the radiation dose and the neutron dose and the gamma dose on the surface of the container, or the value of the neutron dose and the gamma dose on the surface of the container, Or, using the neutron dose and gamma dose of the radioactive material to be stored, the dose rate at the site boundary of the storage building is below a given limit value, the wall thickness of the storage building, or the storage building A radioactive substance storage container storage facility, characterized in that the thickness of a shielding member that shields the radiation from the surface of the container to the outside is calculated, and the calculated result is used to manufacture the container. 2. Formed by a metal and a neutron shield,
In a radioactive substance storage container in which a radioactive substance is hermetically stored, the thickness of the shielding member for shielding the radiation from the container surface to the outside of the building storing the container and the value of the elemental composition are used to store the radioactive substance. The dose rate at the site boundary of the building is less than or equal to the limit value, and the total weight of the container is smaller than the given limit value, the thickness of the metal of the container and the neutron shield are calculated, and the A radioactive substance storage container, which is manufactured using the calculation results. 3. Formed by a metal and a neutron shield,
In a radioactive substance storage container in which a radioactive substance is hermetically stored, the thickness of the shielding member for shielding the radiation from the container surface to the outside of the building storing the container and the value of the elemental composition are used to store the radioactive substance. The dose rate at the site boundary of the building is less than or equal to the limit value, and the weight of the neutron shield in the container is smaller than the given limit value, and the thicknesses of the metal and neutron shield in the container are calculated. , A radioactive substance storage container manufactured by using the calculation result. 4. Formed by a metal and a neutron shield,
In a radioactive substance storage container in which a radioactive substance is hermetically stored, the thickness of the shielding member for shielding the radiation from the container surface to the outside of the building storing the container and the value of the elemental composition are used to store the radioactive substance. The dose rate at the site boundary of the building is less than or equal to the limit value, and the dose rate on the container surface is smaller than the given limit value, the thickness of each metal of the container and the neutron shield is calculated, A radioactive substance storage container manufactured by using the calculation result. 5. Formed by a metal and a neutron shield,
A radioactive substance storage container that contains radioactive substances in a sealed manner,
And in a storage building that stores the container, the ratio of the radiation dose and the neutron dose and gamma dose on the surface of the container, or the value of the neutron dose and the gamma dose on the surface of the container, or the neutron dose of the radioactive material to be stored and Using gamma dose, the dose rate at the site boundary of the storage building is less than or equal to the limit value, and the thickness of the container, and the thickness of the shielding member that shields the radiation from the container surface to the outside of the storage building. The thickness of the metal and the neutron shield of the container, and a shield that shields the radiation from the container surface to the outside of the storage building so that the sum of the thicknesses is smaller than a given limit value. A radioactive substance storage container and a radioactive substance storage container storage facility, which are manufactured by calculating the thickness of a member and using the calculation result. 6. Formed by a metal and a neutron shield,
A radioactive substance storage container that contains radioactive substances in a sealed manner,
And in a storage building that stores the container, the ratio of the radiation dose and the neutron dose and gamma dose on the surface of the container, or the value of the neutron dose and the gamma dose on the surface of the container, or the neutron dose of the radioactive material to be stored and Using gamma dose, the dose rate at the site boundary of the storage building is below the limit value, and the metal and neutron shield material cost of the container, and the radiation from the container surface to the outside of the storage building. The sum of the material costs of the shielding member for shielding the container, the thickness of each metal of the container and the neutron shield, and the surface of the container with respect to the outside of the storage building so that the sum is less than a given limit value. The thickness of the shielding member that shields the radiation from the plant was calculated, and the radioactive substance storage container and the radioactive substance collection characterized by being manufactured using the calculated results. Container storage facilities.