JP5875942B2 - Radioactive material storage facility - Google Patents

Description

  The present invention relates to a radioactive material storage facility, and more particularly to a radioactive material storage facility suitable for application to a nuclear power plant suitable for storing radioactive materials such as spent fuel assemblies and radioactive waste.

  Spent fuel assemblies removed from the reactor core in the reactor pressure vessel of the nuclear power plant are stored in the fuel storage pool in the reactor building and stored in the pool for a predetermined period until they are transported to the nuclear fuel reprocessing facility. Stored in. However, the operation of nuclear fuel reprocessing facilities in Japan is delayed, and the number of spent fuel assemblies stored in the fuel storage pool is increasing. For this reason, the construction of an intermediate storage facility for storing spent fuel assemblies until they are transported to the nuclear fuel reprocessing facility outside the fuel storage pool has been studied. In this intermediate storage facility, a metal cask or a concrete cask containing a plurality of spent fuel assemblies is stored.

  An example of a cask storage building that is an intermediate storage facility is described in JP-A-2002-323592. The cask storage building includes a storage building having a first ceiling for storing a plurality of casks containing spent fuel assemblies in an internal cask storage area. An exhaust tower is provided on the first ceiling of the storage building, and an air supply port for introducing cooling air into the storage building is formed on the side wall of the storage building. The ceiling of the storage building is a double ceiling at the position of the exhaust tower, and a second ceiling is provided below the first ceiling. An air exhaust passage communicated with the interior of the storage building is formed between the first ceiling portion and the second ceiling portion, and the air exhaust passage communicates with the exhaust tower through an exhaust port formed in the first ceiling portion. This exhaust port is provided in the middle of the second ceiling portion. The cooling air flowing into the cask storage area of the storage building from the air supply port cools the cask in the cask storage area, passes through the air exhaust passage formed between the first ceiling part and the second ceiling part, The gas is exhausted from an exhaust port formed in one ceiling to the exhaust tower. This cooling air rises in the exhaust tower and is exhausted to the outside through an exhaust hole formed at the upper end of the exhaust tower.

  Japanese Patent Application Laid-Open No. 2006-322894 describes a spent fuel storage facility that is an intermediate storage facility. This spent fuel storage facility stores a cask containing spent fuel assemblies in a building. The ceiling of the building has a double structure of the first ceiling and the second ceiling arranged below the first ceiling. An air passage is formed between the first ceiling and the second ceiling, and an exhaust tower is provided on the first ceiling near the side wall of the building. An air discharge port that communicates the air passage with the exhaust tower is formed in the first ceiling. The second ceiling is formed with a slit-like opening that connects the cask storage area in the building and its air passage. Cooling air for cooling the cask is supplied to the cask storage area from an air supply port formed in the building. The air in the cask storage area warmed by the cooling of the cask is guided to the exhaust tower through the slit-shaped opening, the air passage and the air discharge port, and is exhausted to the outside environment.

JP 2002-323592 A JP 2006-322894 A

  The spent fuel storage facility described in JP-A-2002-323592 and JP-A-2006-322894 is a dry storage facility, and a cask containing a plurality of spent fuel assemblies stored in a building. In order to cool the air, air cooling by natural ventilation is adopted. It is necessary to attach a garage for rainwater countermeasures at the exhaust outlet of the exhaust tower provided on the ceiling of the building to exhaust the cooling air to the outside so that rain does not enter the exhaust tower. Since the pressure loss of the exhaust tower increases due to the installation of the louver, in order to satisfy the heat removal performance of the cask stored in the cask storage area by the cooling air, the position of the exhaust port formed in the exhaust tower is set higher. Must. By taking such measures, the earthquake resistance of the spent fuel storage facility becomes severe, and the economic efficiency of the spent fuel storage facility is impaired.

  In order to increase the height of the spent fuel storage facility for the purpose of improving heat removal performance, a structure in which a stack is attached can be considered. However, it becomes more difficult to operate the ceiling crane across the entire building of the spent fuel storage facility, and the operational complexity increases. In addition, in the spent fuel storage facility, in order to ensure the radiation shielding performance, the length of the exhaust passage must be increased to reduce the radiation streaming.

  An object of the present invention is to provide a radioactive substance storage facility in which rainwater entering from an exhaust port formed in a ceiling can be easily discharged and a cask can be easily transported.

A feature of the present invention that achieves the above-described object is to provide a building having a first ceiling and a second ceiling disposed below the first ceiling, and having an exhaust passage formed between the first ceiling and the second ceiling. Prepared,
The exhaust passage has an inflow port that communicates with a cask storage area formed below the second ceiling in the building, and communicates with an exhaust port formed in the first ceiling.
An inclined surface is formed on the upper surface of the second ceiling, which is the lower surface of the exhaust passage,
This inclined surface is high on the inlet side and low on the exhaust side,
The drain passage connected to the exhaust passage on the exhaust port side is open to the outside of the building.

  The inclined surface formed on the upper surface of the second ceiling, which is the lower surface of the exhaust passage communicated with the exhaust port formed in the first ceiling, is higher on the inlet side of the exhaust passage and lower on the exhaust port side. Since the drain passage connected to the exhaust passage on the exhaust port side opens to the outside of the building, the rain that has entered the exhaust passage from the exhaust port gathers on the exhaust passage side of the exhaust passage and It can be easily discharged outside the building. In addition, since it is not necessary to provide a cooling air exhaust tower in the building, the effective height of the building can be earned, so that the first ceiling and the second ceiling can be raised, and the ceiling is located above the cask storage area. A crane can be installed. For this reason, the cask stored in the cask storage area can be moved by the overhead crane, and the cask can be easily transported.

  ADVANTAGE OF THE INVENTION According to this invention, the drainage of the rainwater which enters from the exhaust port formed in the ceiling of a radioactive substance storage facility is easy, and conveyance of a cask becomes easy.

1 is a longitudinal sectional view of a radioactive substance storage facility according to a preferred embodiment of the present invention. It is II-II sectional drawing of FIG.

  Examples of the present invention will be described below.

  A radioactive substance storage facility according to a preferred embodiment of the present invention will be described with reference to FIGS.

  The radioactive substance storage facility 1 of the present embodiment includes a building 2 having a first ceiling 7 located on the outside and second ceilings 8A and 8B arranged below the first ceiling 7. The building 2 has a pair of opposing side walls 3 and another pair of opposing side walls 4, and the length of the side walls 3 is longer than the length of the side walls 4. For this reason, the building 2 is long in the direction in which the side wall 3 extends. The second ceiling 8A is attached to the two side walls 3 and the one side wall 4, and the second ceiling 8A is attached to the two side walls 3 and the other one side wall 4. A plurality of openings (inflow ports) 11 are formed between the second ceiling 8A and the second ceiling 8B. These openings 11 are arranged in the direction in which the side wall 3 extends. The second ceiling 8 </ b> A and the second ceiling 8 </ b> B are joined at portions other than these openings 11. Each opening part 11 is arrange | positioned in the center part of the side wall 4 in the direction where the side wall 4 is extended. Each opening 11 communicates with the cask storage area 6 formed below the second ceilings 8A and 8B in the building 2.

  The first ceiling 7 and the second ceiling 8 </ b> A, and the first ceiling 7 and the second ceiling 8 </ b> B are coupled to each other by a plurality of support portions 15 arranged in parallel to the side wall 4. A plurality of exhaust passages 10B arranged in parallel with each other are formed between the first ceiling 7 and the second ceiling 8B. These exhaust passages 10B are partitioned by a support portion 15 (see FIG. 2). A plurality of exhaust passages 10A arranged so as to be parallel to each other are formed between the first ceiling 7 and the second ceiling 8A. These exhaust passages 10A are partitioned by a support portion 15 in the same manner as the exhaust passage 10B. One exhaust passage 10 </ b> A and one exhaust passage 10 </ b> B communicate with one opening 11. This exhaust passage 10 </ b> A extends from the opening 11 to be communicated toward one side wall 3, and communicates with an exhaust port 16 </ b> A formed in the first ceiling 7 near the side wall 3. The exhaust passage 10 </ b> B extends from the communicating opening 11 toward the other side wall 3, and communicates with an exhaust port 16 </ b> B formed in the first ceiling 7 in the vicinity of the side wall 3.

  An inclined surface 9A is formed on the upper surface of the second ceiling 8A. The inclined surface 9A is higher on the opening 11 side and lower on the exhaust port 16A side, and is inclined from the opening 11 of the exhaust passage 10A toward the side wall 3 located on the exhaust port 16A side. A drain passage 12A is formed in the side wall 3 located on the exhaust port 16A side, and communicates the exhaust passage 10A and the outside of the building 2. The opening on the exhaust passage 10A side of the drain passage 12A opens near the inclined surface 9A.

  An inclined surface 9B is formed on the upper surface of the second ceiling 8B. The inclined surface 9B is higher on the opening 11 side and lower on the exhaust port 16B side, and is inclined from the opening 11 of the exhaust passage 10B toward the side wall 3 located on the exhaust port 16B side. A drain passage 12B is formed in the side wall 3 located on the exhaust port 16B side, and communicates the exhaust passage 10B and the outside of the building 2. An opening of the drain passage 12B on the exhaust passage 10B side opens near the inclined surface 9B.

An air supply port 5 communicated with the outside of the building 2 is formed in each side wall 3. A radiation shielding wall 20 is provided on the inner surface of each side wall 3 and covers each air supply port 5. An air supply passage 17 is formed between the side wall 3 and the radiation shielding wall 20 and connects the air supply port 5 and the cask storage area 6.

The overhead crane 13 is installed on a pair of guide rails (not shown) laid on the upper surface of the opposing radiation shielding wall 20 .

  A plurality of metal casks (or concrete casks) 14 containing a plurality of spent fuel assemblies that are radioactive materials generated from a nuclear power plant are stored in a cask storage area 6 in the building 2. The metal cask 14 carried into the building 2 is moved by the overhead crane 13, and the metal cask 14 is transferred to the storage position in the cask storage area 6 by the overhead crane 13. Each metal cask 14 in the cask storage area 6 is cooled by air taken from the outside. The cooling of the stored metal cask 14 will be described below.

  Air outside the building 2 is taken from the air supply port 5 and flows into the cask storage area 6 through the air supply passage 17. The air flows between the metal casks 14 stored in the cask storage area 6 to cool the metal casks 14. The cooling of the metal cask 14 with air cools a plurality of spent fuel assemblies housed in the metal cask 14. The air whose temperature has risen due to the cooling of the metal cask 14 rises in the cask storage area 6 and flows into the opening 11. A part of the air flowing into the opening 11 is exhausted from the exhaust port 16A to the outside of the building 2 through the exhaust passage 10A. The remaining air that has flowed into the opening 11 is exhausted from the exhaust port 16B to the outside of the building 2 through the exhaust passage 10B. Each metal cask 14 in the cask storage area 6 is cooled by the air flow described above.

  When it rains, part of the rain reaches the exhaust passage 10A through the exhaust port 16A. Since the inclined surface 9A of the second ceiling 8A that forms the lower surface of the exhaust passage 10A is inclined from the opening 11 side toward the exhaust port 16A, the rain that has entered the exhaust passage 10A travels on the inclined surface 9A. , Flows toward the side wall 3 on the exhaust port 16A side, and is discharged out of the building 2 through the drain passage 12A. Since the inclined surface 9B of the second ceiling 8B that forms the lower surface of the exhaust passage 10B is inclined from the opening 11 side toward the exhaust port 16B, the rain that has entered the exhaust passage 10B through the exhaust port 16B is inclined. It flows on the surface 9B toward the side wall 3 on the exhaust port 16B side. Then, this rainwater is discharged out of the building 2 through the drain passage 12B. For this reason, rainwater can be prevented from flowing into the cask storage region 6 through the opening 11.

The drain passage 12A and 12B, the drain discharge port formed in each of the building 2 outside is not shown, and entrained in the air drain water dropping from the drain outlet flows into the air supply port 5 cask It arrange | positions so that it may not flow in in the storage area | region 6. FIG.

  Further, since air flows from the opening 11 toward the exhaust port 16A in the drain passage 12A, rainwater that has entered the exhaust passage 10A from the exhaust port 16A is moved to the exhaust port 16A side by the air flowing in the exhaust passage 10A. Since they are easily collected on the side wall 3 side, they are easily discharged to the drain passage 12A. The rainwater does not flow toward the opening 11 against the air flow.

To flow toward the opening 11 the air even in the drain passage 12B to the exhaust port 16B, rainwater that has entered the exhaust passage 10B through the exhaust port 16B is the side of the exhaust port 16B by the air flowing through the exhaust passage 10 in the B Since it is easy to collect on the side wall 3 side, it is easy to be discharged to the drain passage 12B. The rainwater does not flow toward the opening 11 against the air flow.

  According to the present embodiment, it is possible to remove the louver provided at the exhaust port of the conventional exhaust tower, which is a dominant pressure loss factor, and to reduce the pressure loss of the cooling air passage in the building 2. Thereby, after satisfy | filling the heat removal request | requirement of each metal cask 14 in the cask storage area | region 6, the height of the building 2 can be restrained low.

  In the present embodiment, as described above, the cooling air exhaust ports 16A and 16B having the upper surface opening formed in the first ceiling 7 are used. Therefore, the exhaust ports 16A and 16B which are important in the heat removal evaluation of the metal cask 14 are used. The effective height of the building 2 can be earned without changing the height of the building 2 up to.

  In the present embodiment, since the exhaust ports 16A and 16B are open on the upper surface as described above, it is easy for rain to enter the exhaust passages 10A and 10B through the exhaust ports 16A and 16B. The ceiling has a double structure of the first ceiling 7 and the second ceilings 8A and 8B, and exhaust passages 10A and 10B are formed between the first ceiling 7 and the second ceilings 8A and 8B, respectively. Since the inclined surface 9A toward the one side wall 3 is formed on the upper surface of 8A and the inclined surface 9B toward the other side wall 3 is formed on the upper surface of the second ceiling 8B, the exhaust port formed in the first ceiling 7 Rainwater that has entered the exhaust passages 10A and 10B through 16A and 16B can be easily discharged to the outside of the building 2. For this reason, it is possible to prevent rainwater entering the exhaust passages 10A and 10B from reaching the cask storage area 6 in the building 2 where the metal cask 14 is stored.

  In this embodiment, since it is not necessary to provide an exhaust tower for cooling air in the building 2, the effective height of the building 2 can be earned as described above, so that the first ceiling 7 and the second ceilings 8 </ b> A and 8 </ b> B are made high. can do. For this reason, the overhead crane 13 can be installed in the upper part in the cask storage area 6, and the overhead crane 13 can be moved above the metal cask 14 stored in the cask storage area 6. Transport of the metal cask 14 in the cask storage area 6 becomes extremely easy. It becomes easy to carry the metal cask 14 into the building 2 and carry the metal cask 14 out of the building 2.

The air supply port 5 is covered with a radiation shielding wall 20 disposed inside the side wall 3, and the air supply port 5 is also covered with another radiation shielding wall 18 provided on the side wall 3 outside the side wall 3. Yes. An air supply passage 17 formed between the side wall 3 and the radiation shielding wall 20 and an air supply passage 19 formed between the side wall 3 and the radiation shielding wall 18 extend from the air supply port 5 in the same direction. The air supply passages 17 and 19 can reduce the streaming of radiation emitted from the metal cask 14 stored in the cask storage area 6.

  In addition, since the ceiling of the building 2 has a double structure and duct-shaped exhaust passages 10A and 10B are formed between the first ceiling 7 and the second ceilings 8A and 8B, radiation in these exhaust passages is formed. Streaming is degraded. Furthermore, since the ceiling of the building 2 has a double structure having the first ceiling 7 and the second ceilings 8A and 8B, the intrusion of flying objects from above into the building 2 and the influence of backside peeling are prevented. be able to. Inflow of aviation fuel into the building 2 which is a problem when an airplane is assumed as a flying object can also be prevented.

  DESCRIPTION OF SYMBOLS 1 ... Radioactive material storage facility, 2 ... Building, 3, 4 ... Side wall, 5 ... Air inlet, 6 ... Cask storage area, 7 ... 1st ceiling, 8A, 8B ... 2nd ceiling, 9A, 9B ... Inclined surface, 10A, 10B ... exhaust passage, 11 ... opening, 12A, 12B ... drain passage, 13 ... overhead crane, 14 ... metal cask, 16A, 16B ... exhaust port.

Claims (3)

A building having a first ceiling and a second ceiling disposed below the first ceiling, wherein an exhaust passage is formed between the first ceiling and the second ceiling;
The exhaust passage has an inlet connected to a cask storage area formed below the second ceiling in the building, and is connected to an exhaust port formed in the first ceiling.
An inclined surface is formed on the upper surface of the second ceiling, which is the lower surface of the exhaust passage,
This inclined surface is high on the inlet side and low on the exhaust side,
A radioactive substance storage facility, wherein a drain passage connected to the exhaust passage on the exhaust port side opens to the outside of the building.   The radioactive substance storage facility according to claim 1, wherein the exhaust port is disposed on a side wall side of the building, and the drain passage is formed in the side wall.   The radioactive substance storage facility according to claim 1 or 2, wherein the exhaust port faces upward.

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