KR100449792B1 - Method of controlling the temperature of a closed vessel containing radioactive substance, system for storing a closed vessel, and storage facility - Google Patents

Abstract

The present invention provides a temperature control method of a sealed container capable of safely and stably storing radioactive material for a long time, and a storage system and storage facility of the sealed container. The canister 14 which enclosed the radioactive substance is accommodated in the concrete container 12 of the concrete cask 10. Air introduced into the concrete container from the inlet port 26 provided at the lower end of the concrete container flows through the cooling air flow passage 24 around the canister to cool the canister, and then is discharged from the exhaust port 28 above the concrete container. The storage system is provided with a temperature detector 64 for detecting the temperature of the lower end of the canister, and a shield that can be attached to each of the inlet and exhaust ports. Depending on the detected temperature, shields are fitted to the intake and exhaust ports to reduce their opening area, to adjust the natural airflow of outside air flowing through the cooling air flow path, and to adjust the temperature of the outer surface of the lower end of the canister to be above the dew point temperature and to a predetermined heat resistance temperature. Keep it below.

Description

TECHNICAL OF CONTROLLING THE TEMPERATURE OF A CLOSED VESSEL CONTAINING RADIOACTIVE SUBSTANCE, SYSTEM FOR STORING A CLOSED VESSEL, AND STORAGE FACILITY}

The present invention relates to a temperature control method of a sealed container enclosed with a radioactive material accompanying heat generation, a storage system and a storage facility for storing the sealed container.

The highly radioactive material represented by the used fuel of a nuclear reactor is reprocessed in order to collect | recover useful materials which can be used as fuel again, such as plutonium. These used fuels are stored in a sealed state until reprocessing is performed. As a method of storing such a high radioactive material, a wet method using a storage pool or the like, or a dry method by a cask or the like is known.

The dry method is a storage method which performs natural cooling by air instead of water, and it is drawing attention because development cost is low compared with the wet method. Moreover, although there exist various structures in the cask used for the dry method, the concrete cask which shields the fuel used by the concrete structure attracts attention especially because of low cost. Concrete is excellent as a neutron shielding material, has a lower price than other shielding materials, and also has the advantage of obtaining the strength required as a structure.

Such a concrete cask is provided with the cylindrical concrete container which the upper part and the bottom part were occluded, and the cylindrical metal sealed container which the fuel used for this concrete container was enclosed, what is called a canister is accommodated.

In general, since the canister is heated by the decay heat generated by the used fuel to reach a high temperature of about 200 ° C., the concrete cask is provided with an heat removal structure for removing the decay heat (that is, removing heat). That is, a gap is formed between the inner circumferential surface of the concrete container and the outer surface of the canister, and an air inlet is provided at the bottom of the concrete container, and an exhaust port is provided at the top of the container, respectively. Then, the canister is de-heated and cooled by flowing outside air as cooling air introduced into the concrete container from the intake section by flowing the cooling air flow path and discharging it from the exhaust port.

The concrete cask comprised in this way is responsible for cooling the fuel used by the heat removal structure mentioned above, shielding of radiation by the concrete layer, and sealing of the fuel used by the canister. In addition, the concrete cask needs to store the high radioactive material safely and stably for a long time, and high radiation shielding performance is required for a long time.

However, when the canister housed in the concrete cask is provided near the shore with a concrete cask for contacting the outside air by natural circulation cooling, there is a fear that sea salt particles cause corrosion of the canister and stress corrosion debris.

That is, the temperature of the canister is usually higher in the upper part than in the lower part by generation of the used fuel. Therefore, when the calorific value of the fuel used by long term storage falls and the temperature of the whole canister falls, there exists a possibility that the lower part of a canister may fall below dew point temperature. In this case, since moisture containing sea salt particles in the cooling air condenses and adheres to the outer surface of the lower part of the canister, corrosion and stress corrosion debris may occur when SUS304 or 316, which is a general corrosion resistant member, is used.

When corrosion of the canister, stress corrosion debris and the like occur, the shielding of the radiation and the sealing of the radioactive material cannot be maintained, and it is difficult to maintain safety and soundness.

SUMMARY OF THE INVENTION Since the present invention has been made in view of the above, an object of the present invention is to provide a temperature control method of a sealed container capable of safely and stably storing radioactive material for a long time, and a storage system and a storage facility of the sealed container. .

In order to achieve the above object, the temperature control method of the airtight container according to the present invention includes a container body containing a metal airtight container in which a radioactive material is enclosed, a substantially cylindrical container body formed of concrete, and the container. An air inlet provided in the lower end of the main body, an exhaust port provided in the upper end of the container main body, and a cooling air flow path formed between an inner surface of the accommodating part and an outer surface of the sealed container, the air introduced into the container main body from the inlet port; A temperature control method of a closed container for controlling the temperature of the closed container housed in a concrete storage container including a heat removal part which removes heat generated from the radioactive material and discharges from the exhaust port by flowing in the air. Detecting a temperature of a lower end portion of the hermetically sealed container housed in a housing portion, According to the detected temperature, the natural ventilation amount of the outdoor air flowing through the cooling air flow path is adjusted, and the temperature of the closed container is maintained at a temperature lower than the dew point temperature and below a predetermined heat resistance temperature of the closed container. Control method.

Moreover, according to the temperature control method of the sealed container which concerns on this invention, the opening area of at least one of the said intake port and the exhaust port is adjusted according to the detected temperature, The natural airflow amount of the said outdoor air is adjusted.

A storage system according to the present invention includes a metal sealed container in which a radioactive material is enclosed, a storage unit accommodating the sealed container therein, a substantially cylindrical container body formed of concrete, and an inlet provided at a lower end of the container body. And an exhaust port provided at an upper end of the container body, and a cooling air flow path formed between an inner surface of the accommodating portion and an outer surface of the sealed container, and the air introduced into the container body from the inlet port flows through the cooling air flow path. A concrete storage container including a heat removal part for removing heat generated from the exhaust port and discharging from the exhaust port, a temperature detector for detecting a temperature of a lower end portion of the closed container accommodated in the storage part, and the detected temperature. For controlling the natural ventilation amount of the outside air flowing through the cooling air flow path, That of having a control means for maintaining the temperature of the lower end of the outer surface below the dew point temperature or more and a given heat-resistant temperature of a storage system according to claim.

The storage system further includes a temperature detector that detects a temperature of a lower end portion of the sealed container accommodated in the accommodating part, and adjusts an amount of natural airflow of the outside air flowing through the cooling air flow path in accordance with the detected temperature. And an adjusting means for maintaining the temperature of the outer surface of the lower end of the lower end portion at or above the dew point temperature and below the predetermined heat resistance temperature.

According to the storage system according to the present invention, the adjustment means includes an adjustment member for adjusting the opening area of at least one of the intake port and the exhaust port to adjust the natural airflow amount of the outside air.

According to the temperature control method and storage system of the sealed container comprised as mentioned above, when the concrete storage container is installed in the environment containing sea salt particle by maintaining the temperature of the outer surface of the lower end part of a sealed container more than dew point temperature and more than predetermined heat-resistant temperature, Even if it is possible to prevent dew condensation (moisture) including sea salt particles on the outer surface of the sealed container. Thereby, the generation of corrosion and stress corrosion debris in the sealed container can be reliably prevented, and a temperature control method and a storage system capable of safely and stably storing radioactive material for a long time can be realized.

Moreover, the storage facility which concerns on this invention is a storage facility which stores the some metal sealed container in which the radioactive material was enclosed, respectively, WHEREIN: The ceiling in which the installation bed in which the said several sealed container was mounted, and the plurality of inlet and exhaust ports are provided. A plurality of concrete walls including a plurality of concrete walls, an intake passage for introducing cooling air introduced from the intake port to the periphery of the sealed container, a temperature detector for detecting a temperature of a lower end portion of the sealed container located on the installation bed side, And adjusting means for adjusting the natural air flow rate of the outside air flowing through the intake passage in accordance with the detected temperature, and for maintaining the temperature of the outer surface of the lower end of the sealed container above the dew point temperature and below the predetermined heat resistance temperature. Storage facility.

Moreover, according to the storage facility which concerns on this invention, the said adjustment means is equipped with the adjustment member which adjusts the opening area of at least one of the said intake port and the exhaust port, and adjusts the natural airflow amount of the said outside air.

According to the storage facility configured as described above, the outdoor air containing sea salt particles is maintained by adjusting the natural air flow rate of the outdoor air flowing through the intake passage to maintain the temperature of the outer surface of the lower end of each airtight container above the dew point temperature and below the predetermined heat resistance temperature. Even if it flows in, it becomes possible to prevent condensation of moisture, including sea salt particles, on the outer surface of the sealed container. Thereby, generation | occurrence | production of corrosion and stress corrosion debris of a sealed container can be prevented reliably, and the storage facility which can store a radioactive material safely and stably for a long time can be implement | achieved.

1 is a perspective view showing a cut part of the concrete cask of the storage system according to the first embodiment of the present invention,

2 is a longitudinal sectional view of the concrete cask,

3 is a sectional view showing an upper portion of a canister housed in the concrete cask;

4 is a view showing a mounting state of a shielding body and a shielding body mounted on an inlet and an exhaust port of the concrete cask;

5 is a view showing a relationship between the temperature difference between the canister bottom and the outside air, the fastening width of the intake and exhaust ports, and the natural airflow amount of the outside air;

6 is a perspective view showing a canister storage facility according to a second embodiment of the present invention;

7 is a sectional view of the canister storage facility.

Explanation of symbols for the main parts of the drawings

10 concrete cask 12 concrete container

14 canister 15 container body

16: basket 18: used fuel assembly

22: accommodating portion 24: cooling air flow path

26, 80: inlet port 28, 84: exhaust port

62: thermocouple 64: detector

70: shield 77: canister storage facility

97: temperature detector 98: louver

97: temperature detector

Referring to the drawings, a storage system having a concrete cask according to a first embodiment of the present invention will be described in detail.

As shown in FIGS. 1-3, the concrete cask 10 as a concrete storage container is provided with the concrete container 12 formed by concrete and functioning as a shielding structure, The canister 14 is contained in this concrete container. ) Is housed. The canister 14 as a hermetically sealed container has a cylindrical container body 15 formed of metal and closed at both ends, and the fuel assembly 18 used in the container body in a state supported by the basket 16 is used. A plurality of) are enclosed. These used fuel assemblies 18 are, for example, used fuels for nuclear reactors, and contain radioactive materials with generation of heat with decay heat and generation of radiation. In addition, the container main body 15 has a welded-closed structure so that the internal radioactive material does not leak to the outside.

The concrete container 12 of the concrete cask 10 has a cylindrical shape in which the bottom is closed, as shown in FIGS. 1 and 2, and is formed, for example, about 6 m in height and about 4 m in diameter. It is formed about 0.9m. The upper opening of the concrete container 12 is closed by the cover 20 made of concrete whose outer surface is covered with a carbon steel sheet. The lid 20 is fastened to the upper end of the concrete container 12 by a plurality of bolts 21. In addition, reinforcing bars (not shown) are arranged in the concrete wall of the concrete container 12.

In the concrete container 12, a cylindrical housing portion 22 is defined by the inner circumferential surface and the lid 20 of the concrete container. And the canister 14 is accommodated in this accommodating part 22. As shown in FIG. The canister 14 is mounted on the plurality of ribs 31 formed on the bottom surface of the housing portion 22 and is disposed coaxially with the concrete container 12. Moreover, the canister 14 is accommodated in the accommodating part 22 with the outer peripheral surface having a predetermined | prescribed clearance gap, for example, about 10 cm clearance gap between the inner peripheral surface of the concrete container 12. As shown in FIG.

And the cooling air flow path 24 through which cooling air flows is formed by the clearance gap between the outer peripheral surface of the canister 14 and the inner peripheral surface of the concrete container 12. As shown in FIG. The cooling air flow passage 24 is formed over the entire circumference of the outer circumferential surface of the canister 14 over the entire axial length of the outer circumferential surface.

A plurality of, for example, four inlets 26 are formed at the bottom of the concrete container 12, and four exhaust ports 28 are formed at the upper end of the concrete container 12, respectively, communicating with the cooling air flow passage 24. Doing. The four intake openings 26 are provided at equal intervals apart from each other along the circumferential direction of the concrete container 12, and are open to the outer peripheral surface of the bottom of the concrete container 12. In addition, the exhaust ports 28 are provided at equal intervals from each other along the circumferential direction of the concrete container 12, and are open to the outer circumferential surface of the upper end of the concrete container 12. The inlet port 26 and the exhaust port 28 are each formed in a rectangular cross-sectional shape.

These intake ports 26, exhaust ports 28 and cooling air flow passages 24 constitute heat removal units for removing concrete cask 10 by natural circulation cooling of air. That is, since the inside of the concrete cask 10 becomes high temperature by the heat_generation | fever from the canister 14, the outside air as cooling air introduce | transduced into the concrete container 12 from the inlet port 26 passes through the cooling air flow path 24. As shown in FIG. It flows in the circumference | surroundings of the canister 14, and heats the canister 14 and the concrete container 12 in between, and cools it. The cooling air heated by the heat from the canister 14 and heated up is discharged from the exhaust port 28 to the outside of the concrete container 12.

On the other hand, a cylindrical liner 30 made of a metal such as carbon steel is provided on the inner circumferential surface of the concrete container 12. The liner 30 made of metal has a higher heat transfer property than concrete, and promotes heat transfer of heat generated by the used fuel assembly 18 and also functions to shield radiation from the used fuel assembly 18, mainly? -Rays. Have

Next, the structure of the canister 14 is demonstrated in detail.

As shown in FIG. 2 and FIG. 3, the canister 14 is provided with the substantially cylindrical container main body 15 with the lower end closed and the upper opening. The container main body 15 is formed of nonmagnetic metal, such as stainless steel, for example. In the container body 15, a plurality of fuel assemblies 18 used in a state supported by the basket 16 are enclosed.

The support member 42 is fixed to the inner peripheral surface of the upper end of the container main body 15, and the disk-shaped shielding body 44 is mounted on this support member, and the upper opening of the container main body is occluded. Moreover, in the upper end part of the container main body 15, the disk-shaped 1st cover 48 overlaps with the shield 44, and the upper opening of the container main body is closed. The peripheral part of the upper end side of the 1st cover 48 is welded to the inner peripheral surface of the container main body 15 over the perimeter. The shield 44 and the first cover 48 are formed with a flow path 50 for exhaust and drainage in the container body 15, which is formed by a plug body 51 fixed to the first cover 48. It is sealed.

Moreover, in the upper end part of the container main body 15, the disk-shaped 2nd cover 52 overlaps with the 1st cover 48, and is attached. The periphery of the upper end side of the second lid 52 is welded to the inner circumferential surface of the vessel body 15, whereby the second lid 52 closes the top opening of the vessel body 15 and the second lid 48. Located outside of.

In this way, the upper opening of the container body 15 is hermetically closed by the shield 44, the first lid 48, and the second lid 52. These shields 44, the first cover 48, and the second cover 52 are formed of metal, such as stainless steel, for example.

In addition, a sealed space 55 is formed between the first cover 48 and the second cover 52, and a gas having a higher thermal conductivity than air, such as helium (He), is a pressurized gas. It is enclosed. As a result, the sealed space 55 is pressurized at about 5 atmospheres. Similarly, helium is enclosed in the container main body 15 and pressurized about 3 atmospheres.

On the other hand, the storage system according to the first embodiment is a temperature detector for detecting the temperature of the lower end of the canister 14 accommodated in the concrete cask 10, the inlet port 26 and the exhaust port of the concrete cask 10 ( A plurality of shielding bodies for adjusting the opening area of 28) and for adjusting the natural ventilation amount of cooling air are provided.

Specifically, as shown in FIG. 2, the storage system has a plurality of thermocouples 62 as a temperature detector and a detector 64 electrically connected to these thermocouples. The thermocouple 62 is provided in multiple places in the concrete container 12 in the bottom wall outer surface of the container main body 15 of the canister 14. The detector 64 is provided outside the concrete container 12 and is connected to the heat transfer table 62 through, for example, one inlet port 26.

In addition, as shown in FIG. 4, the shielding body 70 is formed in the dimension corresponding to the width | variety of the inlet port 26 and the exhaust port 28 of the concrete cask 10, The inlet port 26 and the exhaust port 28 It is possible to selectively bond to. In other words, the shielding body 70 is formed in, for example, a substantially rectangular parallelepiped shape made of carbon steel, and a flange 71 is provided on the outer end side thereof, and a resin 72 as a neutron shielding material is filled on the inner end side thereof. Further, guide grooves 74 extending along the axial direction of the shield are formed on two opposite surfaces of the shield 70, respectively. In addition, the flange 71 is provided with a hole for inserting the bolt through.

On the other hand, two sets of guide ribs 76 which are engageable with the guide grooves 74 of the shielding body 70 are formed at both ends of each inlet port 26, respectively. Similarly, two sets of guide ribs 76 which are engageable with guide grooves 74 of the shielding body 70 are formed at both ends of each exhaust port 28, respectively.

Then, the shielding body 70 is inserted into the inlet port 26 with the guide grooves 74 on the concrete cask 10 side coupled to the guide grooves 74, and the flanges 71 are inserted into the concrete container 12. By fastening the bolts in this way, the inlet port 26 can be partially blocked by the shielding body 70, and the opening area of the inlet port can be reduced. Two shielding bodies 70 can be attached to the inlet port 26, and the opening area of the inlet port 26 can be further reduced by attaching two shields 70.

Similarly, one or two shields 70 can be attached to each exhaust port 28, and the opening area can be reduced by attaching the shield and partially closing the exhaust port 28. FIG.

Then, at least one of the inlet port 26 and the exhaust port 28 is partially closed by the shielding body 70, and the natural nature of the outside air flowing through the cooling air flow passage 24 of the concrete container 12 by reducing the opening area. Aeration rate can be adjusted.

According to the storage system configured as described above, during the storage period of the canister 14 by the concrete cask 10, the temperature detector continuously or periodically monitors the temperature of the bottom surface of the canister 14. That is, the temperature of the bottom surface of the canister 14 is detected by the thermocouple 62 and monitored by the detector 64.

In the concrete cask 10 configured as described above, the canister 14 housed in the concrete container 12 is heated by heat from the used fuel assembly 18 to raise the temperature, and the center and top of the canister are then It becomes high temperature compared with a bottom part. Therefore, the outside air is naturally circulated through the cooling air flow passage 24 of the concrete cask 10, so that the canister 14 and the concrete container 12 are kept below a predetermined heat resistance temperature. When the calorific value of the used fuel assembly 18 falls and the temperature of the whole canister 14 falls, there exists a possibility that a bottom part may fall below dew point temperature.

Therefore, when the temperature of the bottom surface of the canister 14 is higher than a predetermined temperature, for example, the intake temperature + 30 ° C by the temperature detector, the inlet port 26 and the exhaust port 28 of the concrete cask 10 are all open. The canister 14 and the concrete vessel 12 are cooled so as not to exceed a predetermined heat resistance temperature.

In addition, when the temperature of the bottom surface of the canister 14 is lowered to a predetermined temperature by the temperature detector, one shielding body 70 is attached to each inlet port 26 and the exhaust port 28, and the inlet port and the exhaust port are Reduce the opening area. As a result, the amount of aeration of outdoor air that naturally circulates through the cooling air flow passage 24 of the concrete container 12 is reduced, the cooling efficiency of the canister 14 due to the outside air is lowered, and the temperature drop at the bottom of the canister is suppressed, and the dew point is reduced. Keep above temperature.

In this state, monitoring is continued by the temperature detector, and when the temperature of the bottom surface of the canister 14 drops to a predetermined temperature again, one shield member 70 is added to each intake port 26 and the exhaust port 28. And further reduce the opening area of these intake and exhaust ports. Thereby, the airflow amount of the outdoor air which circulates naturally in the cooling air flow path 24 is further reduced, the temperature fall of a canister bottom part is suppressed, and it maintains above dew point temperature.

5 shows the relationship between the temperature difference between the bottom of the canister 14 and the outside air, the fastening width of the intake and exhaust ports, and the natural airflow amount of the outside air.

Thus, according to the temperature of the canister bottom detected by the temperature detector, the opening area of the inlet port 26 and the exhaust port 28 is adjusted by the shielding body 70, and the outside air which naturally circulates through the cooling air flow path 24 is used. By adjusting the ventilation amount, the temperature of the canister 14 and the concrete container 12 can be kept below heat resistance temperature. At the same time, even in long term storage, the temperature of the canister bottom can be kept above the dew point temperature. Therefore, even when the concrete cask 10 is installed in an environment containing sea salt particles, condensation of water containing sea salt particles and the like on the outer surface of the canister 14 can be prevented. Thereby, generation | occurrence | production of the corrosion and stress corrosion debris of the canister 14 can be prevented reliably. Thereby, the generation of corrosion and stress corrosion debris of the canister 14 can be prevented reliably, and the radioactive material can be stored safely and stably for a long time.

In addition, although the shielding body 70 is attached to both the inlet port 26 and the exhaust port 28, and the natural flow of cooling air was adjusted in the 1st Example mentioned above, only a shield body in at least one of an inlet port and an exhaust port is provided. Even if it is equipped with, it is possible to adjust the natural flow of cooling air.

In addition, the shield 70 which partially obstructs the inlet port 26 and the exhaust port 28 is not limited to the above rectangular parallelepiped shape, but is provided as an open / close door or louver shield provided on the outer surface of the concrete container so as to be slidable or rotatable. It is okay.

Next, a canister storage facility according to a second embodiment of the present invention will be described.

As shown in Figs. 6 and 7, the canister storage facility 77 is entirely formed by a concrete wall and has an installation bed 78 as a floor wall, a ceiling wall 79 and a plurality of side walls 81. Doing.

The ceiling wall 79 is formed with an exhaust tower 85 having two intake towers 82 having a plurality of intake ports 80 and a plurality of exhaust ports 84, respectively, and the intake tower 82 has both ends of the ceiling wall. In addition, the exhaust tower 85 is provided in the center of the ceiling wall, respectively. In the vicinity of each intake tower 82, a partition wall 86 extending from the ceiling wall 79 to the vicinity of the installation bed 78 is provided, and an intake flow path 88 connected to the intake port is formed.

Each intake port 80 of the intake tower 82 is provided with a louver 98 for adjusting its opening area. Then, by adjusting the opening and closing of the louvers 98, the natural airflow amount of the outside air flowing through the intake passage 88 can be adjusted.

In the canister storage facility 77, a plurality of canisters 14 are arranged at predetermined intervals on the installation bed 78. Each canister 14 is configured in the same manner as in the first embodiment described above, and houses the used fuel assembly 18. In addition, the canister storage facility 77 is provided with the intermediate beds 90 arranged in parallel on the installation bed 78 with a predetermined gap. A plurality of circular through holes 91 are formed in the intermediate bed 90, and each canister 14 is inserted into the through hole 91 without a gap and penetrated through the intermediate bed 90. It is mounted on (78). Moreover, the temperature detector 97 which detects the temperature of this bottom surface is provided in the bottom part of each canister 14, and is connected to the detection apparatus which is not shown in figure.

And between the installation bed 78 and the intermediate | middle bed 90, the distribution space 92 through which the outside air which flowed in through the intake port 80 and the intake flow path 88 is defined. The end 90a of the intake tower 82 side of the circulation space 92 is opened to define an inlet 94. The intermediate bed 90 is formed of a metal plate such as, for example, a carbon steel sheet.

According to the canister storage facility 77 comprised as mentioned above, as shown by the arrow in FIG. 7, the cooling air which flowed into the canister storage facility 77 from the intake port 80 of the intake tower 82 is taken into the intake flow path 88. As shown in FIG. Flows downward through, and is introduced near the installation bed 78. A portion of the cooling air introduced then flows from the inlet 94 into the defined distribution space 92 below the intermediate bed 90 and the remainder enters the upper space of the intermediate bed 90.

Cooling air flowing into the circulation space 92 flows around the plurality of canisters 14, and after cooling the canisters 14, is exhausted from the exhaust port 84 to the outside of the canister storage facility 77. Similarly, cooling air introduced into the upper space of the intermediate bed 90 flows around the plurality of canisters 14, cools the canisters 14, and then from the exhaust port 84 to the outside of the canister storage facility 77. Discharged.

According to the canister storage facility 77 comprised as mentioned above, during the storage period of the canister 14, the temperature detector 97 monitors the temperature of the bottom surface of the canister 14 continuously or regularly. When the temperature of the bottom of the canister 14 is higher than a predetermined temperature, for example, the intake temperature is higher than + 30 ° C by the temperature detector 97, the louver 98 provided in the intake port 80 is kept open. In order to prevent the canister 14 from exceeding a predetermined heat resistance temperature, a sufficient amount of cooling air is introduced into the intake passage 88 to cool.

In addition, when the temperature of the bottom part of the canister 14 is reduced to predetermined temperature by the temperature detector 97, the louver 98 is rotated, the opening area of each intake port 80 is reduced, and the intake flow path 88 is closed. Reduce the natural aeration of the flowing outdoor air. As a result, the amount of outside air introduced into the interior space of the canister storage facility 77 is reduced, and as a result, the cooling efficiency of the canister 14 due to the outside air is lowered, and the temperature drop at the bottom of the canister is suppressed, so as to be above the dew point temperature. Keep it.

In this state, the monitoring is continued by the temperature detector 97, and when the temperature of the bottom of the canister 14 decreases to a predetermined temperature, the louver 98 is rotated to reset the opening area of each intake port 80 again. By reducing, the natural airflow amount of the outside air flowing through the intake passage 88 is further reduced. Thereby, the cooling efficiency of the canister 14 by external air is reduced, the temperature fall of a canister bottom part is suppressed, and it maintains above dew point temperature.

Thus, according to the canister storage facility 77 of the said structure, according to the temperature of the canister bottom part detected by the temperature detector 97, the opening area of the intake port 80 is adjusted by the louver 98, and canister storage The temperature of the canister 14 can be kept below heat-resistant temperature by adjusting the ventilation amount of the outdoor air which circulates naturally in a facility. In addition, even in long-term storage, the temperature of the canister bottom can be maintained above the dew point temperature. Therefore, even when the storage facility 77 is installed in an environment containing sea salt particles, condensation of water containing sea salt particles and the like on the outer surface of the canister 14 can be prevented. Thereby, the generation of corrosion and stress corrosion debris of the canister 14 can be prevented reliably, and the radioactive material can be stored safely and stably for a long time.

In addition, this invention is not limited to the above-mentioned embodiment, A various deformation | transformation is possible within the scope of this invention. For example, in the second embodiment, the louver functioning as the adjusting means is not limited to the intake port, but may be provided in the intake flow path 88. In addition to the intake port, a louver or the like may be provided in the exhaust port of the storage facility.

As described above, according to the present invention, by maintaining the temperature of the lower end of the airtight container above the dew point temperature, the temperature control method of the airtight container that can safely and stably store radioactive material for a long time, and the storage system of the airtight container And storage facilities.

Claims (10)

A container body having a sealed container made of a metal sealed container containing radioactive material therein, a substantially cylindrical container body formed of concrete, an inlet provided at a lower end of the container body, an exhaust port provided at an upper end of the container body, and the housing part A cooling air flow path formed between an inner surface of the airtight container and an outer surface of the sealed container, the air introduced into the container body from the inlet port flows through the cooling air flow path to remove heat generated from the radioactive material, and to discharge from the exhaust port. In the temperature control method of the airtight container which controls the temperature of the said airtight container accommodated in the concrete storage container provided with a heat removal part, Detecting a temperature of a lower end portion of the hermetically sealed container housed in the accommodation portion, According to the detected temperature, the natural ventilation amount of the outdoor air flowing through the cooling air flow path is adjusted, and the temperature of the outer surface of the lower end of the sealed container is maintained above the dew point temperature and below a predetermined heat resistance temperature. Method of temperature control in closed containers. The method of claim 1, According to the detected temperature, the opening area of at least one of the intake port and the exhaust port is adjusted, and the natural ventilation amount of the outside air is adjusted. Method of temperature control in closed containers. The method of claim 2, At least one of the intake port and the exhaust port is partially blocked to adjust the natural airflow of the outside air; Method of temperature control in closed containers. The method of claim 3, wherein At least one of the inlet and the exhaust port is equipped with a shield and partially occluded Method of temperature control in closed containers. In a storage system, A metal sealed container containing a radioactive material, An interior of the container containing the sealed container therein, a substantially cylindrical container body formed of concrete, an inlet provided at the lower end of the container body, an exhaust port provided at the upper end of the container body, and an inner surface of the container and the sealed container. Concrete having a cooling air flow path formed between the outer surface of the inlet, and the air introduced into the container body from the inlet port flows to the cooling air flow path to remove heat generated from the radioactive material, and has a heat removing section discharged from the exhaust port The storage container, A temperature detector for detecting a temperature of a lower end portion of the hermetically sealed container housed in the storage portion; And adjusting means for adjusting the natural air flow rate of the outside air flowing through the cooling air flow path according to the detected temperature, and for maintaining the temperature of the outer surface of the lower end of the airtight container above the dew point temperature and below the predetermined heat resistance temperature. By Storage system. The method of claim 5, wherein The adjusting means is provided with an adjusting member for adjusting the opening area of at least one of the intake port and the exhaust port, and for controlling the natural airflow amount of the outside air. Storage system. The method of claim 6, The adjustment member is detachably mounted to at least one of the intake port and the exhaust port, and has a shield that partially closes at least one of the intake port and the exhaust port. Storage system. A storage facility for storing a plurality of metal hermetically sealed containers each containing radioactive material, A plurality of concrete walls including an installation bed on which the plurality of sealed containers are mounted, and a ceiling wall on which a plurality of intake and exhaust ports are provided; An intake passage for introducing cooling air introduced from the intake port into the vicinity of the closed container; A temperature detector for detecting a temperature of a lower end portion of the sealed container located on the installation bed side; And adjusting means for adjusting the natural air flow rate of the outside air flowing through the intake passage in accordance with the detected temperature, and maintaining the temperature of the outer surface of the lower end of the sealed container above the dew point temperature and below the predetermined heat resistance temperature. doing Storage facility. The method of claim 8, The adjusting means is provided with an adjusting member for adjusting the opening area of at least one of the intake port and the exhaust port, and for controlling the natural airflow amount of the outside air. Storage facility. The method of claim 9, The adjusting member is provided in at least one of the inlet and exhaust ports, and has a louver that can adjust the opening and closing amount. Storage facility.