JP2015031523A - Heat removing apparatus for concrete cask, and concrete cask - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make continuous thermal management unnecessary even in a case where the flow channel of internal cooling air is in a closed loop.SOLUTION: A heat removing apparatus 1 for a concrete cask 2 that takes in internal cooling air 5 for cooling a canister 4 housed in a concrete container 3 from an air intake 6 and discharges the air through an exhaust outlet 7 positioned in a higher position than the air intake 6 is provided with a circulatory passage 8 that is arranged outside the concrete container 3 and makes continuous the exhaust outlet 7 and the air intake 6 to guide the internal cooling air 5 discharged from the exhaust outlet 7 to the air intake 6 while cooling the air and heat radiating means 21 that is disposed above the circulatory passage 8 and, when the temperature of the internal cooling air 5 rises above a presupposed level, opens the inside of the circulatory passage 8 to the atmosphere.

Description

  The present invention relates to a heat removal device for a concrete cask and a concrete cask having the same. More specifically, the present invention relates to a heat removal apparatus for a concrete cask that cools the inside of a concrete cask while circulating the internal cooling air that is shut off from an external salty environment with a closed loop and is circulated by natural convection, and a concrete including the same. It is about cask.

  Spent fuel generated by nuclear power is stored in a concrete cask and stored under proper management. The concrete cask includes a canister that stores spent fuel and a cask body that stores the canister. Since the fission product (FP) in the spent fuel continues to decay after removal from the reactor, the canister generates heat even during storage. For this reason, for example, in the concrete cask described in Japanese Patent Application Laid-Open No. 2003-194729, as shown in FIG. 5, a flow path 103 is provided between the canister 101 containing the FP and the cask body 102, and cooling The heat of the canister 101 is removed by flowing air 104. An air inlet 105 is provided in the lower part of the cask main body 102 and an air outlet 106 is provided in the upper part. The cooling air 104 heated by cooling the canister 101 rises in the air flow path 103 and moves to the air. The air is discharged from the outlet 106, and as a result, new air is taken in as cooling air 104 from the air inlet 105. That is, the cooling air 104 taken from the outside flows from the air inlet 105 to the flow path 103 to the air outlet 106 by natural convection by heating.

  By the way, it is known that stress corrosion cracking (SCC) may occur in the canister 101 during storage, and the salt content in the cooling air 104 greatly affects the occurrence of stress corrosion cracking. Therefore, the air outlet 106 and the air inlet 105 are connected by an air passage so that the flow path of the cooling air 104 is closed and the cooling air 104 discharged from the air outlet 106 is circulated to the air inlet 105. Thus, it is considered to prevent the salt from adhering to the canister 101 by blocking from the external salt environment (for example, Patent Document 2).

JP 2003-194729 A JP 2010-145111 A

  However, when the flow path of the cooling air 104 is a closed loop, the cooling air 104 is cut off from the external environment, so it is more important to grasp the temperature change, and it is necessary to constantly manage the temperature of the cooling air 104. There is. The spent fuel is stored for a long period of time, and if the temperature management of the cooling air 104 is continuously continued, the management burden becomes enormous.

  An object of the present invention is to provide a concrete cask heat removal device that can eliminate the need for continuous temperature control even when the cooling air flow path is a closed loop, and a concrete cask including the same.

  In order to achieve this object, the invention according to claim 1 is directed to an exhaust gas that is provided at a position higher than the air intake port by taking in the internal cooling air for cooling the canister accommodated in the concrete container from the air supply port. In the heat removal device for the concrete cask discharged from the mouth, it is arranged outside the concrete container and communicates with the exhaust port and the air supply port to guide the internal cooling air discharged from the exhaust port to the air supply port while cooling it. A circulation path and a heat dissipating means that is provided in the upper part of the circulation path and opens the inside of the circulation path to the atmosphere when the temperature of the internal cooling air becomes higher than a temperature assumed in advance.

  Therefore, after cooling the canister in the concrete cask, the internal cooling air is discharged from the exhaust port, cooled by the outside air while flowing through the circulation passage, and circulated to the air supply port. That is, the flow path of the internal cooling air becomes a closed loop, and the internal cooling air is blocked from the external salt environment. Ascending force due to heating acts on the internal cooling air, and descending force due to cooling acts in the circulation passage outside the concrete cask. For this reason, internal cooling air circulates by natural convection. Further, when the temperature of the internal cooling air rises abnormally and exceeds the assumed temperature, the heat radiating means opens the circulation passage to the atmosphere. Thereby, the temperature of internal cooling air falls.

  In the concrete cask heat removal apparatus according to claim 2, the heat radiating means is also provided in the lower part of the circulation passage. Therefore, when the temperature of the internal cooling air rises abnormally and exceeds the assumed temperature, the lower part is opened in addition to the upper part of the circulation path, and air is circulated also in the lower part of the circulation path.

  The concrete cask heat removal apparatus according to claim 3 is an opening in which the heat radiating means is closed by a lid-like member, and the lid-like member is deformed or melted by the heat of the internal cooling air. It is fixed to the circulation passage and is released by its own weight due to deformation or melting of the fixing means and opens the opening. Therefore, when the temperature of the internal cooling air rises abnormally and exceeds the assumed temperature, the lid-like member is removed, the opening is opened, and the inside of the circulation passage is opened to the atmosphere.

  According to a fourth aspect of the present invention, there is provided a concrete cask heat removal apparatus comprising connecting means for preventing the lid-like member from falling. Therefore, the detached lid-like member is suspended by the connecting means.

  Furthermore, the invention according to claim 5 is a concrete cask that takes in the internal cooling air for cooling the canister accommodated in the concrete container from the air supply port and discharges it from the exhaust port provided at a position higher than the air supply port. In addition, the heat removal apparatus described in any one of claims 1 to 4 is provided. Accordingly, a concrete cask including the heat removal device is configured.

  In the concrete cask heat removal apparatus according to claim 1, since the flow path of the internal cooling air that cools the inside of the concrete container is a closed loop, the inside of the concrete container can be shut off from the external environment, and contains salt or the like. It is possible to prevent outside air from flowing into the concrete container. Therefore, the canister can be prevented from corroding due to salt and moisture contained in the outside air.

  When the temperature of the internal cooling air rises abnormally and exceeds the assumed temperature, the heat radiating means opens the circulation passage to the atmosphere, so that the temperature of the internal cooling air can be automatically lowered. Therefore, even if the flow path of the internal cooling air is closed, it is possible to eliminate the need for constant temperature monitoring of the internal cooling air, reduce the management burden, and ensure passive safety.

  In the concrete cask heat removal device according to claim 2, since the heat radiating means is also provided at the lower part of the circulation passage, when the temperature of the internal cooling air rises abnormally and exceeds the assumed temperature, In addition to the upper part, the lower part can be opened, and the temperature of the internal cooling air can be lowered more efficiently.

  In the concrete cask heat removal apparatus according to claim 3, the heat dissipating means is an opening covered with a lid-like member, and the lid-like member comes off when the temperature of the internal cooling air rises abnormally and exceeds the assumed temperature. The opening opens and the inside of the circulation passage is opened to the atmosphere, so the heat of the internal cooling air can be activated using the heat of the internal cooling air to lower the temperature of the internal cooling air, ensuring passive safety. Can do.

  Note that the concrete temperature limit value in the concrete cask structure standard is described as 175 ° C (short time) in Notification No. 452 of the Japan Society of Mechanical Engineers. Even if an increase is observed, it is considered to be acceptable if it is below this temperature limit value.

  In the concrete cask heat removal apparatus according to claim 4, since the connecting means for preventing the lid-like member from dropping is provided, the lid-like member can be prevented from falling from a high position, and the lid-like member can be prevented from falling. The loss of the member can be prevented. In addition, since the lid-like member can be held in a suspended state, it is easy for a person performing maintenance inspection to notice the detachment of the lid-like member, to easily confirm the operation of the heat dissipating means, and to easily notice the temperature abnormality of the internal cooling air. .

Furthermore, in invention of Claim 5, the concrete cask provided with said heat removal apparatus is comprised.

It is sectional drawing which shows an example of embodiment of the heat removal apparatus of this invention. It is sectional drawing which expands and shows the thermal radiation means of the heat removal apparatus. It is a top view which shows a mode that the heat removal apparatus was attached to the concrete cask. It is a top view which shows other embodiment of the heat removal apparatus of this invention, and shows a mode that it attached to the concrete cask. It is a perspective view which cuts and shows the conventional concrete cask partially.

  Hereinafter, the configuration of the present invention will be described in detail based on the form shown in the drawings.

  FIG. 1 to FIG. 3 show an example of an embodiment of a concrete cask heat removal apparatus (hereinafter simply referred to as a heat removal apparatus) of the present invention. The heat removal apparatus 1 is an exhaust port provided at a position higher than the air supply port 6 by taking in the internal cooling air 5 for cooling the canister 4 accommodated in the concrete container 3 of the concrete cask 2 from the air supply port 6. This is applied to the concrete cask 2 discharged from 7, and is disposed outside the concrete container 3 and communicates the exhaust port 7 and the air supply port 6 to cool the internal cooling air 5 discharged from the exhaust port 7. A circulation passage 8 that leads to the air supply port 6 is provided. Moreover, this invention is grasped | ascertained also as the concrete cask 2 provided with the heat removal apparatus 1. FIG.

  A canister 4 for storing spent fuel is placed on a support leg 11 and stored in a concrete container 3. The upper opening of the concrete container 3 is closed by a lid 12. A cooling passage 13 through which the internal cooling air 5 flows is provided between the canister 4 and the concrete container 3. An air supply port 6 that leads to the cooling passage 13 is provided at the bottom of the concrete container 3. An exhaust port 7 that leads to the cooling passage 13 is provided between the concrete container 3 and the lid 12. Since the air supply port 6 and the exhaust port 7 communicate with each other through the circulation passage 8, it is preferable that the same number is provided at the same position as seen from above, for example, as shown in FIG. However, if the internal cooling air 5 can be circulated from the exhaust port 7 to the air supply port 6 by the circulation passage 8, it is necessary to provide the air supply port 6 and the exhaust port 7 at the same position when viewed from above. In addition, the number of supply ports 6 and exhaust ports 7 may be different. Further, since the air supply port 6 and the exhaust port 7 are communicated with each other by the circulation passage 8, it is preferable that the air supply port 6 and the exhaust port 7 are opened to the peripheral surface of the concrete cask 2. However, if the air supply port 6 and the exhaust port 7 can be communicated with each other by the circulation passage 8, it is not necessary to open the air supply port 6 and the exhaust port 7 on the peripheral surface of the concrete cask 2. May be opened on the bottom surface of the concrete cask 2, for example, and the exhaust port 7 may be opened on the top surface of the concrete cask 2, for example. In the present embodiment, air supply ports 6 and exhaust ports 7 are provided on the peripheral surface of the concrete cask 2 at, for example, four locations at equal intervals in the circumferential direction.

  One heat removal device 1 is provided for each set composed of one air supply port 6 and one exhaust port 7. Since the concrete cask 2 of this embodiment is provided with four sets of air supply ports 6 and exhaust ports 7, a maximum of four heat removal devices 1 are attached to the concrete cask 2.

  The circulation passage 8 is made of a material that has excellent thermal conductivity and can secure rigidity as a passage, for example, a metal material such as copper, aluminum, and stainless steel. Heat exchange is performed between the internal cooling air 5 and the outside air via the tube wall 8a of the circulation passage 8. That is, the tube wall 8 a of the circulation passage 8 is a cooling wall, and the internal cooling air 5 is cooled by the tube wall 8 a that is cooled by the outside air while flowing through the circulation passage 8.

  A mounting side air supply port 16 connected to the exhaust port 7 of the cooling passage 13 is provided at the upper end of the circulation passage 8, and a mounting side exhaust port 17 connected to the air supply port 6 of the cooling passage 13 is provided at the lower end. ing. In the present embodiment, the mounting-side air supply port 16 and the mounting-side exhaust port 17 are formed in a cylindrical shape, and the tip of the cylindrical portion is inserted into the exhaust port 7 or the air supply port 6 of the cooling passage 13 to connect. Leakage of the internal cooling air 5 from the part and inflow of outside air are prevented.

  The heat removal apparatus 1 is provided with a heat dissipating means 21 that is provided above the circulation passage 8 and opens the inside of the circulation passage 8 to the atmosphere when the temperature of the internal cooling air 5 becomes higher than a temperature assumed in advance. In the present embodiment, the heat radiating means 21 is provided at a position that extends horizontally from the mounting side air supply port 16 of the circulation passage 8, but is not limited to this position. The heat dissipating means 21 of the present embodiment is an opening 23 closed by a lid-like member 22, and the lid-like member 22 is fixed to the circulation passage 8 by fixing means 24 that is deformed or melted by the heat of the internal cooling air 5. The opening 23 is opened by its own weight due to deformation or melting of the fixing means 24. However, the lid-like member 22 is not limited to this. For example, the lid-like member 22 is moved by being driven by a shape memory alloy that is deformed when the temperature of the internal cooling air 5 becomes higher than a temperature assumed in advance. Those that open the screen may be used.

  The fixing means 24 for attaching the lid-like member 22 to the circulation passage 8 is an adhesive such as a low melting point bonding metal. The low melting point bonding metal has a melting point between the normal temperature limit value of 90 ° C. and the abnormal temperature limit value of 175 ° C. (short time) specified in the Japan Society of Mechanical Engineers Notification No. 452 as the limit temperature of the concrete cask. It is desirable to have For example, U alloy or the like can be used. The melting point of U alloy 138G is 138 ° C., and it melts when the temperature of the cooling air rises abnormally and the temperature of the U alloy reaches 138 ° C. Thereby, the opening part 23 which the lid-like member 22 removed and was blocked by its own weight is opened. The low melting point bonding metal is not limited to U alloy 138G. Further, the adhesive is not limited to the low melting point bonding metal. The temperature is appropriately selected according to the temperature (assumed temperature) at which the lid-like member 22 is to be removed. Further, the peripheral edge of the lid-like member 22 is bonded and sealed over the entire periphery, and leakage of cooling air is prevented in normal times.

  In the present embodiment, the portion of the circulation passage 8 where the opening 23 is provided is inclined downward, and the lid-like member 22 is provided obliquely downward. Therefore, when the fixing means 24 is melted or deformed, the lid-like member 22 comes off due to its own weight and falls.

  In the present embodiment, the heat radiating means 21 is also provided below the circulation passage 8. The heat dissipating means 21 provided in the lower part of the circulation passage 8 is configured in the same manner as the heat dissipating means 21 provided in the upper part. In the present embodiment, the lower heat dissipating means 21 is provided at a position horizontally extending from the mounting side exhaust port 17 of the circulation passage 8, but is not limited to this position.

  In this embodiment, the lower heat dissipation means 21 is provided in addition to the upper heat dissipation means 21, but the lower heat dissipation means 21 may be omitted.

  The upper heat radiating means 21 is provided with a connecting means 25 for preventing the lid-like member 22 from falling. The connecting means 25 is, for example, a wire that connects the lid-like member 22 to the circulation passage 8. However, the connecting means 25 is not limited to a wire, and any other means may be used as long as it can prevent the lid-like member 22 from dropping, such as a chain, rope, string, or the like. The connecting means 25 prevents the detached lid-like member 22 from falling to the ground and preventing loss. Further, since the lid-like member 22 can be held in a suspended state, it is easy for a person who performs maintenance and inspection to notice that the lid-like member 22 is detached and to confirm the operation of the heat dissipating means 22, and the temperature of the internal cooling air 5 is abnormal. It becomes easy to notice.

  The heat removal apparatus 1 is provided in the middle of the circulation passage 8 and includes a sampling pipe 26 that can collect a test sample of the internal cooling air 5. Although the four heat removal devices 1 are attached to the concrete cask of this embodiment, the sampling pipes 26 may be provided for all four heat removal devices 1, and some of the four heat removal devices 1 may be provided. The sampling pipe 26 may be provided only in the heat removal apparatus 1.

  The sampling pipe 26 is preferably provided, for example, at a height that can be reached by a person performing maintenance and inspection.

  The sampling pipe 26 is provided with an open / close valve 27. The internal cooling air 5 can be collected by opening the on-off valve 27, and the internal cooling air 5 can be prevented from leaking by closing the on-off valve 27. The on-off valve 27 is opened when a sample of the internal cooling air 5 is collected.

  In the present embodiment, a pressure gauge 29 for measuring the pressure of the internal cooling air 5 is provided in the sampling pipe 26. The inside of the canister 4 is pressurized to a pressure of, for example, 0.5 to 8 atm by a gauge pressure. When the canister 4 is cracked and a large leak occurs, the pressure of the internal cooling air 5 is increased. By providing the sampling pipe 26 with the pressure gauge 29, it is easy to constantly monitor the pressure of the internal cooling air 5, and the pressure abnormality of the internal cooling air 5 can be detected at an early stage. Therefore, it is possible to detect an abnormality in the sealing performance of the canister 4 early and easily. The pressure gauge 29 may be provided with a communication function so that the measured value can be confirmed at a remote place.

  The heat removal apparatus 1 of the present embodiment is detachable from the concrete container 3. The circulation path 8 is placed on, for example, a carriage 28 and is movable. By placing the circulation passage 8 on the carriage 28, the height of the air supply port 6 and the mounting side exhaust port 17 and the height of the exhaust port 7 and the mounting side air supply port 16 are matched. Therefore, by moving the circulation passage 8 on the carriage 28, the mounting side exhaust port 17 can be inserted into the air supply port 6 and the mounting side air supply port 16 can be inserted into the exhaust port 7 as it is. After these are connected, the installation of the heat removal apparatus 1 is completed by fixing the carriage 28. When disconnecting the heat removal apparatus 1, the carriage 28 is unfixed and moved, and the mounting side air supply port 16 is pulled out from the exhaust port 7, and the mounting side exhaust port 17 is pulled out from the air supply port 6. It ’s fine. As described above, the circulation path 8 can be easily attached and detached.

  The heat removal apparatus 1 may be attached to the concrete cask 2 from the start of use of the concrete cask 2 (initial stage of spent fuel storage) and removed as necessary, or heat removal at the start of use of the concrete cask 2 The heat removal device 1 may be attached to the concrete cask 2 after a certain period of time has elapsed after the start of use without attaching the device 1. For example, corrosion such as stress corrosion cracking (SCC) is a problem when there is a risk of condensation, for example, at the end of storage when the canister 4 is at a certain low temperature, or by storing a low heat generating fuel. This is the case. Therefore, for example, the heat removal apparatus 1 is attached to the concrete cask 2 only when there is a possibility that condensation will occur, and the heat removal apparatus 1 may be removed from the concrete cask 2 when the possibility that condensation will occur is low. good. Since the heat removal apparatus 1 is detachable, it can be used in various ways as described above.

  Next, the operation of the heat removal apparatus 1 will be described.

  When the heat removal device 1 is attached to the concrete cask 2 and the mounting side air supply port 16 is connected to the exhaust port 7 and the mounting side exhaust port 17 is connected to the air supply port 6, the cooling passage 13 and the circulation passage 8 are internal. A closed loop for circulating the cooling air 5 is formed. Since the internal cooling air 5 is heated by cooling the canister 4 in the concrete container 3, a rising force acts on the internal cooling air 5. On the other hand, outside the concrete cask 2, that is, inside the circulation passage 8, the internal cooling air 5 is cooled by exchanging heat with the outside air via the pipe wall 8 a, and therefore the internal cooling air 5 has a downward force. Works. Therefore, the internal cooling air 5 circulates through the cooling passage 13 → the exhaust port 7 → the circulation passage 8 → the air supply port 6 → the cooling passage 13 by natural convection and conveys the heat of the canister 4 to the outside of the concrete container 3.

  The heat dissipation means 21 provided in the circulation passage 8 is heated by the internal cooling air 5. When the temperature of the internal cooling air 5 rises abnormally and the temperature of the fixing means 24 of the heat radiating means 21 exceeds the assumed temperature, the fixing means 24 melts or deforms. Therefore, the lid-like member 22 is removed by its own weight, and the opening 23 is opened. Outside air is taken into the circulation passage 8 through the opened opening 23, and the temperature of the internal cooling air 5 is lowered.

  In this embodiment, the heat radiating means 21 is provided in both the upper and lower portions of the circulation passage 8. However, the internal cooling air 5 immediately after flowing through the concrete container 3 and flowing into the circulation passage 8 is connected to the circulation passage 8. Since the temperature is higher than that of the internal cooling air 5 just before passing through the concrete container 3, the upper heat dissipating means 21 is first actuated and then the lower heat dissipating means 21 is actuated. When the upper and lower heat dissipating means 21, 21 are activated and the openings 23, 23 are opened, the internal cooling air 5 is naturally convected by heating of the canister 4, as in the concrete cask 2 not equipped with the heat removal device 1. As a result, the opening 23 of the lower heat radiating means 21 → the supply port 6 → the cooling passage 13 → the exhaust port 7 → the opening 23 of the upper heat radiating means 21 → the outside flows. That is, although the internal cooling air 5 cannot be blocked from the external salt environment, it is possible to continue cooling by taking in cold outside air.

  In some cases, the temperature of the internal cooling air 5 decreases due to the operation of the upper heat dissipation means 21, and the lower heat dissipation means 21 does not operate. In this case, outflow and inflow of air occur through the opening 23 of the upper heat radiation means 21, and the temperature of the internal cooling air 5 is lowered.

  Thus, when the temperature of the internal cooling air 5 rises abnormally and exceeds the assumed temperature, the heat radiation means 21 opens the circulation passage 8 to the atmosphere, so that the temperature of the internal cooling air 5 can be automatically lowered. . Therefore, even if the flow path of the internal cooling air 5 is a closed loop, it is not necessary to constantly monitor the temperature of the internal cooling air 5, the management burden can be reduced, and passive safety can be ensured. .

  Further, since the heat radiating means 21 is also provided in the lower part of the circulation passage 8, when the temperature of the internal cooling air 5 rises abnormally and exceeds the assumed temperature, the lower part can be opened in addition to the upper part of the circulation passage 8. The temperature of the internal cooling air 5 can be lowered more efficiently.

  Further, the heat dissipating means 21 is an opening 23 closed by the lid-like member 22, and when the temperature of the internal cooling air 5 rises abnormally and exceeds the assumed temperature, the lid-like member 22 is detached and the opening 23 opens to open the circulation passage. Since the inside of 8 is opened to the atmosphere, the heat of the internal cooling air 5 can be used to operate the heat dissipating means 21 to lower the temperature of the internal cooling air 5, thereby ensuring passive safety.

  Further, since the connecting means 25 for preventing the lid-like member 22 of the upper heat radiation means 21 from dropping is provided, the lid-like member 22 can be prevented from dropping from a high position, and the lid-like member 22 is lost. Can be prevented. Further, since the lid-like member 22 can be held in a suspended state, it is easy for a person who performs maintenance and inspection to notice that the lid-like member 22 is detached and to confirm the operation of the heat dissipating means 21, and the temperature of the internal cooling air 5 is abnormal. It becomes easy to notice.

  Further, since the internal cooling air 5 can be collected from the sampling pipe 26, the internal cooling air 5 that is blocked from the external environment can be easily collected. When an inert gas such as helium gas, for example, a gas sealed in the canister 4 is detected from the collected internal cooling air 5, it is considered that an abnormality such as a crack has occurred in the canister 4. In this heat removal apparatus 1, since the internal cooling air 5 can be easily collected, it is easy to inspect the soundness of the canister 4 based on the component analysis of the internal cooling air 5. In addition, the flow path of the internal cooling air 5 is a closed loop, and the gas leaked from the canister 4 is accumulated in the internal cooling air 5 and the concentration becomes high, so that the detection is easy. From this point, the soundness inspection of the canister 4 is easy.

  In the present invention, since the internal cooling air 5 is circulated to cool the canister 4, the inside of the concrete container 3 can be shut off from the external environment, and outside air containing salt or the like is prevented from flowing into the concrete container 3. be able to. Therefore, it is possible to prevent the canister 4 from being corroded due to salt or moisture contained in the outside air. In particular, radioactive waste storage facilities are often built on the seaside, and the outside air contains a lot of salt. In the present invention, since the outside air in such a state is not introduced into the concrete container 3, the salt content in the outside air does not adhere to the welded portion of the canister 4 and the stress corrosion is caused by the salt contained in the outside air. It is possible to reliably prevent cracks and the like from occurring and progressing.

  In addition, since the internal cooling air 5 can be naturally circulated using the heat of the canister 4, the power for driving these components becomes unnecessary, and the maintenance and management of the device 1 is facilitated. Durability can be improved.

  Moreover, since the heat removal apparatus 1 can be detached from the concrete cask 2, the heat removal apparatus 1 can be easily maintained. Further, it becomes possible to retrofit the existing concrete cask 2.

  Further, since the outside air is used for cooling the internal cooling air 5, the air for cooling is not lost, the internal cooling air 5 can be reliably cooled, and the reliability is excellent.

  The above-described embodiment is an example of a preferred embodiment of the present invention, but is not limited thereto, and various modifications can be made without departing from the scope of the present invention. For example, in the above description, one heat removal device 1 is provided for one air supply port 6 and one exhaust port 7. However, the present invention is not necessarily limited to this configuration. One heat removal device 1 may be provided for the port 6 and the plurality of exhaust ports 7. For example, as shown in FIG. 4, one heat removal device 1 may be provided for all of the air supply ports 6 and all of the exhaust ports 7. In this case, it is preferable that the heat removal apparatus 1 is divided into a plurality of units so that the heat removal apparatus 1 can be attached to and detached from the concrete cask 2.

  In the above description, outside air is used for cooling the internal cooling air 5, but is not limited to outside air. For example, a gas other than the outside air may be used, or a liquid such as water may be used.

  Moreover, you may provide the flow path which flows the gas and cooling fluid which cool the internal cooling air 5, and in this case, the internal cooling air 5 can be cooled more efficiently. For example, a flow path through which secondary cooling air that cools the surface of the circulation passage 8 flows may be provided so that the low-temperature secondary cooling air is always in contact with the surface of the circulation passage 8.

  In the above description, the heat removal apparatus 1 is movable by being placed on the carriage 28. However, the means for moving the heat removal apparatus 1 is not necessarily limited to the carriage 28. For example, a forklift or crane It may be made to move using a conveying means such as, or the heat removal apparatus 1 may be made to move by providing wheels.

  Further, in the above description, the mounting side air supply port 16 and the mounting side exhaust port 17 are formed in a cylindrical shape, and these are inserted into the exhaust port 7 or the air supply port 6 of the cooling passage 13, so that the passages 8 and 13 are formed. Although the connection is made, the means for connection is not limited to this, and other means may be used as long as leakage of the internal cooling air 5 from the connection portion and inflow of outside air can be prevented.

  In the above description, the pressure gauge 29 is provided in the sampling pipe 26, but the pressure gauge 29 may be omitted.

  In the above description, the sampling pipe 26 is provided, but the sampling pipe 26 may be omitted.

  In the above description, the connecting means 25 is provided only on the upper heat radiating means 21. However, the connecting means 25 may be provided on the lower heat radiating means 21 in addition to or instead of the upper heat radiating means 21.

  In the above description, the heat removal apparatus 1 is detachable from the concrete cask 2, but it may not be detachable.

DESCRIPTION OF SYMBOLS 1 Heat removal apparatus 2 Concrete cask 3 Concrete container 4 Canister 5 Internal cooling air 6 Air supply port 7 Exhaust port 8 Circulation path 21 Heat radiation means 22 Lid-like member 23 Opening part 24 Fixing means 25 Connection means

Claims (5)

  In a concrete cask heat removal apparatus for taking in internal cooling air for cooling a canister housed in a concrete container from an air supply port and discharging it from an exhaust port provided at a position higher than the air supply port, the concrete container A circulation passage that is disposed outside the exhaust passage and communicates the exhaust port and the air supply port and guides the internal cooling air discharged from the exhaust port to the air supply port while cooling, and an upper portion of the circulation passage A heat removal device for a concrete cask, comprising: a heat dissipating means that opens the circulation passage to the atmosphere when the temperature of the internal cooling air is higher than a temperature assumed in advance.   2. The concrete cask according to claim 1, wherein the heat radiating means is also provided at a lower portion of the circulation passage.   The heat dissipating means is an opening closed by a lid-like member, and the lid-like member is fixed to the circulation passage by fixing means that is deformed or melted by the heat of the internal cooling air, and the fixing means 3. A concrete cask heat removal apparatus according to claim 1, wherein the opening is opened by its own weight by deformation or melting.   The heat removal apparatus for a concrete cask according to claim 3, further comprising connecting means for preventing the lid-like member from falling.   5. The concrete cask according to claim 1, wherein internal cooling air for cooling the canister accommodated in the concrete container is taken in from the air supply port and discharged from an exhaust port provided at a position higher than the air supply port. A concrete cask comprising the heat removal device according to claim 1.

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