JP2013127432A - Support structure for spent fuel rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a support structure for a spent fuel rack which enables stable support by preventing adjacent spent fuel racks from colliding with one another.SOLUTION: A cell storage part 41 into which spent fuels can be inserted from above it in the vertical direction can be put in a spent fuel pool 31 with plural legs 42, and a plurality of adjacent spent fuel racks 32 are coupled with one another with plural damper gears 51.

Description

  The present invention relates to a spent fuel rack support structure for temporarily storing spent fuel rods taken out from a nuclear reactor.

  One of the nuclear power plants is a pressurized water reactor. In this pressurized water reactor, light water is used as a reactor coolant and a neutron moderator, and high-temperature and high-pressure water that does not boil throughout the primary system is used. Water is sent to a steam generator to generate steam by heat exchange, and this steam is sent to a turbine generator to generate electricity.

  In such a nuclear power plant, a spent fuel pool for temporarily storing spent fuel rods taken out from the pressurized water reactor is provided in the reactor building. A spent fuel rack that supports the spent fuel rods in an upright state is installed. Such a spent fuel rack is generally fixed to a floor surface via a base plate. However, when the spent fuel rack is fixed in this way, a large load is applied to the base plate when an earthquake occurs, resulting in an increase in size.

  For this reason, the horizontal force that acts in the event of an earthquake, etc. is used together with the effect of adding water to the fluid by slidably placing it on the floor without fixing the spent fuel rack to the spent fuel pool. It has been proposed to absorb by sliding the spent fuel rack. As such a spent fuel rack, there exists a thing described in the following patent document 1, for example.

JP 2011-149904 A

  In the conventional spent fuel rack described above, the cell storage portion is supported by a plurality of legs, and a plurality of the spent fuel racks are placed on the bottom surface of the spent fuel pool with a predetermined gap. In this case, the amount and position of the fuel stored in the cell storage unit are different in each spent fuel rack. Therefore, when each spent fuel rack vibrates due to the occurrence of an earthquake or the like, there is a possibility that adjacent spent fuel racks collide with each other because their behaviors are different.

  The present invention solves the above-described problems, and an object of the present invention is to provide a spent fuel rack support structure that enables stable support by preventing collision between adjacent spent fuel racks.

  In order to achieve the above object, the spent fuel rack support structure of the present invention has a cell storage portion into which spent fuel can be inserted from above along the vertical direction, and a predetermined gap is provided in the spent fuel pool. A plurality of spent fuel racks placed adjacent to each other with a gap therebetween are connected to each other by a damper device.

  Accordingly, the horizontal swing of the plurality of spent fuel racks is suppressed by the damper device, so that collision between adjacent spent fuel racks can be prevented, and stable support can be made possible. Seismic resistance can be improved.

  In the spent fuel rack support structure according to the present invention, the upper portions of the plurality of spent fuel racks are connected to each other by the damper device.

  Therefore, a plurality of spent fuel racks are placed at the bottom of the spent fuel pool, and the upper part is connected by a damper device, so that the horizontal swing of the spent fuel rack is properly suppressed to prevent collision. can do.

  In the spent fuel rack support structure according to the present invention, the damper device dampens vibrations by movement of a fluid filled therein.

  Accordingly, the plurality of spent fuel racks can be easily prevented from colliding with each other because the horizontal shaking is suppressed by the movement of the fluid filled in the damper device.

  In the spent fuel rack support structure of the present invention, the damper device is characterized in that vibration is damped by a dilatant fluid filled therein.

  Therefore, by using the dilatant fluid as the fluid that suppresses the horizontal shaking of the spent fuel rack, it is possible to effectively prevent the spent fuel racks from colliding with each other.

  In the support structure for a spent fuel rack according to the present invention, the damper device attenuates vibrations by magnetizing a magnetic fluid filled therein.

  Therefore, by using the magnetic fluid as the fluid that suppresses the horizontal shaking of the spent fuel rack, it is possible to effectively prevent the spent fuel racks from colliding with each other.

  In the spent fuel rack support structure of the present invention, the damper device is characterized in that each end in the longitudinal direction is detachably provided in the vertical direction with respect to the plurality of spent fuel racks adjacent to each other.

  Accordingly, the damper device can be easily attached to and detached from the spent fuel rack in the vertical direction, and the spent fuel rack can be easily removed from the spent fuel pool and adjusted in position.

  According to the spent fuel rack support structure of the present invention, a plurality of spent fuel racks are placed adjacent to each other with a predetermined gap in the spent fuel pool, and the adjacent spent fuel racks are connected to each other. Since they are connected by the damper device, it is possible to prevent the adjacent spent fuel racks from colliding with each other by the damper device, enabling stable support and improving the earthquake resistance of the spent fuel rack.

FIG. 1 is a schematic view of a spent fuel pool showing a spent fuel rack support structure according to an embodiment of the present invention. FIG. 2 is a schematic diagram showing a support structure for the spent fuel rack of the present embodiment. FIG. 3 is a schematic view showing a connecting portion formed in the spent fuel rack. FIG. 4 is a perspective view showing a connecting member for connecting a spent fuel rack. FIG. 5 is a schematic diagram showing the operation of the spent fuel rack support structure. FIG. 6 is a schematic diagram illustrating a modified example of the support structure of the spent fuel rack. FIG. 7 is a schematic configuration diagram illustrating a nuclear power plant. FIG. 8 is a schematic view showing a nuclear reactor containment vessel.

  Hereinafter, preferred embodiments of a spent fuel rack support structure according to the present invention will be described in detail with reference to the accompanying drawings. In addition, this invention is not limited by this Example, Moreover, when there exists multiple Example, what comprises combining each Example is also included.

  FIG. 1 is a schematic view of a spent fuel pool representing a spent fuel rack support structure according to an embodiment of the present invention, and FIG. 2 is a schematic view showing a spent fuel rack support structure according to the present embodiment. 3 is a schematic view showing a connecting portion formed in the spent fuel rack, FIG. 4 is a perspective view showing a connecting member for connecting the spent fuel rack, and FIG. 5 is a view showing a support structure for the spent fuel rack. FIG. 6 is a schematic diagram showing a modified example of a spent fuel rack support structure, FIG. 7 is a schematic configuration diagram showing a nuclear power plant, and FIG. 8 is a schematic diagram showing a nuclear reactor containment vessel. It is.

  The nuclear reactor applied to the nuclear power plant of the present embodiment uses light water as a reactor coolant and a neutron moderator to produce high-temperature and high-pressure water that does not boil over the entire primary system, and sends this high-temperature and high-pressure water to a steam generator. This is a pressurized water reactor (PWR) that generates steam by heat exchange and sends the steam to a turbine generator to generate electricity.

  That is, in the nuclear power plant having this pressurized water reactor, as shown in FIG. 7, the pressurized water reactor 12 and the steam generator 13 are stored in the reactor containment vessel 11, and this pressurized water atom is stored. The furnace 12 and the steam generator 13 are connected via cooling water pipes 14 and 15, a pressurizer 16 is provided in the cooling water pipe 14, and a cooling water pump 17 is provided in the cooling water pipe 15. In this case, light water is used as the moderator and the primary cooling water, and the primary cooling system is controlled by the pressurizer 16 so as to maintain a high pressure state of about 160 atm in order to suppress boiling of the primary cooling water in the core. Yes. Therefore, in the pressurized water reactor 12, light water is heated as primary cooling water by low-enriched uranium or MOX as fuel, and the high-temperature primary cooling water is maintained at a predetermined high pressure by the pressurizer 16. To the steam generator 13. In the steam generator 13, heat exchange is performed between the high-pressure and high-temperature primary cooling water and the secondary cooling water, and the cooled primary cooling water is returned to the pressurized water reactor 12 through the cooling water pipe 15.

  The steam generator 13 is connected to a turbine 18 and a condenser 19 provided outside the reactor containment vessel 11 through cooling water pipes 20 and 21, and a water supply pump 22 is provided in the cooling water pipe 21. ing. Further, a generator 23 is connected to the turbine 18, and a condenser pipe 19 is connected to a water intake pipe 24 and a drain pipe 25 for supplying and discharging cooling water (for example, seawater). Accordingly, the steam generated by exchanging heat with the high-pressure and high-temperature primary cooling water in the steam generator 13 is sent to the turbine 18 through the cooling water pipe 20, and the turbine 18 is driven by this steam to generate the generator 23. To generate electricity. The steam that has driven the turbine 18 is cooled by the condenser 19, and then returned to the steam generator 13 through the cooling water pipe 21.

  As shown in FIG. 8, the reactor containment vessel 11 of the nuclear power plant configured as described above accommodates the above-described pressurized water reactor 12, the steam generator 13, the pressurizer 16, and the like. On the other hand, a fuel handling building 30 is installed adjacent to the reactor containment vessel 11, and a spent fuel pool 31 is provided in the fuel handling building 30, and a spent fuel rack is provided inside the spent fuel pool 31. 32 is installed. The spent fuel rack 32 temporarily stores spent fuel (fuel rods) used in the pressurized water reactor 12, and the spent fuel stored in the spent fuel rack 32 is: The spent fuel pool 31 is filled and can be cooled by circulating cooling water.

  As shown in FIGS. 1 and 2, the spent fuel rack 32 has a square tube shape with a bottom, an upper portion is opened, and a plurality of square tubes are arranged at equal intervals inside and fixed by welding. Thereby, the cell storage part 41 which can insert a spent fuel from upper direction along a perpendicular direction is formed. The spent fuel rack 32 has a plurality of legs 42 attached to the lower part of the cell storage part 41, and each leg 42 is placed on the bottom surface 31 a of the spent fuel pool 31. In the present embodiment, nine spent fuel racks 32 are arranged at a center in the spent fuel pool 31 with a predetermined gap, and a predetermined gap is provided between the spent fuel pool 31 and the wall surface 31 b of the spent fuel pool 31. Is secured. The spent fuel pool 31 is filled with cooling water so that the entire spent fuel rack 32 is immersed therein. Here, nine spent fuel racks 32 are arranged in the spent fuel pool 31, but the number is not limited thereto.

  And in the support structure of the spent fuel rack 32 of a present Example, the adjacent several spent fuel rack 32 is connected with the damper apparatus 51. FIG. In this case, the nine spent fuel racks 32 are arranged in the spent fuel pool 31 with a predetermined gap, and the upper portions of adjacent spent fuel racks 32 are connected by two damper devices 51. ing. That is, each spent fuel rack 32 is connected in two directions intersecting (orthogonal) in the horizontal direction by a plurality of damper devices 51. In this embodiment, the damper device 51 attenuates the vibration of the spent fuel rack 32 by magnetizing the magnetic fluid as the fluid filled therein.

  Specifically, as shown in FIG. 3, the adjacent spent fuel rack 32 has a cutout portion 44 that opens upward in the outer frame portion 43. The notch 44 is communicated so that the first notch 44a and the second notch 44b are orthogonal to each other, so that the plan view has a T shape, and the second notch 44b is not only on the upper side, An opening is made in the outer wall surface of the spent fuel rack 32. The notch 44 is formed from the upper surface of the spent fuel rack 32 to a predetermined depth.

  On the other hand, as shown in FIG. 4, the damper device 51 is configured by connecting two fitting portions 52 by a piston portion 53. Each fitting portion 52 is connected so that the first fitting member 52a and the second fitting member 52b are orthogonal to each other, thereby forming a T shape in plan view, and the second fitting members 52b are connected to each other. The piston part 53 is connected. The fitting portion 52 is formed to have a predetermined height, that is, approximately the same dimension as the depth of the cutout portion 44 of the spent fuel rack 32.

  Therefore, the damper device 51 is detachable in the vertical direction with respect to the notches 44 of the spent fuel rack 32 adjacent to the fitting portions 52 in the longitudinal direction.

  Further, as shown in FIG. 5, the piston portion 53 includes a hollow cylinder 54 fixed to one fitting portion 52, a piston 55 movable within the cylinder 54, and one end portion to the piston 55. It has a rod 57 extended from a support member 56 that is connected and has the other end fixed to the other fitting portion 52, and a magnetic fluid (MR fluid) 58 is filled in the cylinder 54. Further, an electromagnet (coil) 59 is provided on the outer peripheral portion of the cylinder 54 facing the piston 55, and a power supply device 60 is connected to the electromagnet 59. The control device 61 is connected to the power supply device 60 and is connected to the accelerometer 62.

  Accordingly, when the power supply device 60 is not applying current to the electromagnet 59 by the control device 61, the magnetic fluid 58 is in a non-magnetized state, so that the piston 55 can move with little resistance. On the other hand, when the acceleration detected by the accelerometer 62 is equal to or higher than a predetermined acceleration set in advance, the power supply device 60 applies current to the electromagnet 59 by the control device 61, so that the magnetic fluid 58 becomes magnetized, and each particle A coupling force is generated between them, the viscosity increases, and a predetermined resistance force acts when the piston 55 moves. The predetermined acceleration set in advance is preferably an acceleration corresponding to a predetermined seismic intensity when an earthquake occurs, for example.

  As described above, the plurality of spent fuel racks 32 are placed on the floor 31 a of the spent fuel pool 31 by the plurality of legs 42, and the upper portions are connected by the damper device 51. Then, when an earthquake occurs, each spent fuel rack 32 slides on the bottom surface 31 a of the spent fuel pool 31 to suppress shaking. At this time, since the control device 63 receives the detection result from the accelerometer 62 and applies a current to the electromagnet 59 by the power supply device 60, the magnetic fluid 58 is magnetized and a binding force is generated between the particles. Thus, the viscosity increases and a predetermined resistance force acts when the piston 55 moves. Therefore, each damper device 51 is attenuated by absorbing the horizontal vibration between the adjacent spent fuel racks 32, and the collision between the spent fuel racks 32 is prevented.

  In the above description, the magnetic fluid is applied as the fluid filled in the damper device 51. However, the present invention is not limited to this configuration. For example, as shown in FIG. 6, the damper device 71 attenuates the vibration of the spent fuel rack 32 by a dilatant fluid as a fluid filled inside.

  That is, the adjacent spent fuel rack 32 has a notch 44 formed in the outer frame 43. On the other hand, the damper device 71 is configured by connecting two fitting portions 72 by a piston portion 73. In addition, each fitting part 72 is the structure substantially the same as each fitting part 52 of the damper apparatus 51 mentioned above. The piston portion 73 includes a hollow cylinder 74 fixed to one fitting portion 72, a piston 75 movable in the cylinder 74, one end connected to the piston 75, and the other end fitted to the other fitting. A rod 77 extending from a support member 76 fixed to the joint portion 72, and a dilatant fluid 78 is filled in the cylinder 74.

  Therefore, the plurality of spent fuel racks 32 are placed on the floor surface 31 a of the spent fuel pool 31 by the plurality of legs 42, and the upper portions are connected by the damper device 71. Then, when an earthquake occurs, each spent fuel rack 32 slides on the bottom surface 31 a of the spent fuel pool 31 to suppress shaking. At this time, the cylinder device 74 and the piston 75 try to move relative to each other in the damper device 71. Here, since the dilatant fluid 78 is hermetically filled in the cylinder 74, when the piston 75 moves in the cylinder 74, the viscosity of the dilatant fluid 78 increases, the movement resistance of the piston 75 increases, and the moving speed increases. Is reduced. Therefore, each damper device 71 is attenuated by absorbing the horizontal vibration between the adjacent spent fuel racks 32 and the collision between the spent fuel racks 32 is prevented.

  In addition, in order to suppress sedimentation of the magnetic fluid 58 and the dilatant fluid 78 in the cylinders 54 and 74 in the damper devices 51 and 71, fins (stirring blades) may be provided inside the cylinders 54 and 74. desirable.

  As described above, in the spent fuel rack support structure of the present embodiment, the cell storage portion 41 into which the spent fuel can be inserted from above along the vertical direction is formed in the spent fuel pool 31 by the plurality of legs 42. The plurality of adjacent spent fuel racks 32 are connected to each other by a plurality of damper devices 51 and 71.

  Accordingly, the horizontal swing of the plurality of spent fuel racks 32 is suppressed by the damper devices 51 and 71, so that collision between adjacent spent fuel racks 32 can be prevented and stable support can be achieved. The behavior can be stabilized and the earthquake resistance of the spent fuel rack 32 can be improved.

  In the spent fuel rack support structure of this embodiment, the upper portions of the plurality of spent fuel racks 32 are connected by a plurality of damper devices 51 and 71. Accordingly, the plurality of spent fuel racks 32 are placed on the bottom surface 31a of the spent fuel pool 31 and the upper parts are connected by the damper devices 51 and 71, so that the spent fuel racks 32 can be properly shaken horizontally. It is possible to prevent the collision by suppressing it.

  Further, in the spent fuel rack support structure of this embodiment, the damper device 51 attenuates vibrations by movement of the fluid filled therein. Specifically, the damper device 51 attenuates vibration by magnetizing the magnetic fluid 58 filled therein. Therefore, in the plurality of spent fuel racks 32, the horizontal swing is suppressed by magnetizing the magnetic fluid 58 filled in the damper device 51, thereby easily preventing the spent fuel racks 32 from colliding with each other. Can do. Further, by using the magnetic fluid 58 as a fluid for suppressing the horizontal shaking of the spent fuel rack 32, it is possible to effectively prevent the spent fuel racks 32 from colliding with each other.

  Further, in the spent fuel rack support structure of the present embodiment, the damper device 71 attenuates vibrations by movement of the fluid filled therein. Specifically, the damper device 71 dampens vibration by a dilatant fluid 78 filled therein. Accordingly, the horizontal shaking of the plurality of spent fuel racks 32 is suppressed by the dilatant fluid 78 filled in the damper device 71, so that collisions between the spent fuel racks 32 can be easily prevented. In addition, by using the dilatant fluid 78 as a fluid that suppresses the horizontal shaking of the spent fuel rack 32, it is possible to effectively prevent the spent fuel racks 32 from colliding with each other and to simplify the structure. be able to.

  Further, in the spent fuel rack support structure of the present embodiment, the damper devices 51 and 71 are configured by connecting the fitting portions 52 and 72 positioned at the respective end portions in the longitudinal direction by the piston portions 53 and 73, The fitting portions 52 and 72 are detachable in the vertical direction with respect to the adjacent spent fuel rack 32. Accordingly, the damper devices 51 and 71 can be easily attached to and detached from the spent fuel rack 32 in the vertical direction, and the spent fuel rack 32 is easily taken out and adjusted with respect to the spent fuel pool 31. be able to.

  In each of the above-described embodiments, nine spent fuel racks 32 are arranged in the spent fuel pool 31. However, the number and arrangement of the spent fuel racks 32 are not limited, and the size of the spent fuel pool 31 is not limited. What is necessary is just to set suitably according to a shape. Further, the shape of the spent fuel rack 32 is not limited to the embodiment. Furthermore, although the notch 44 in the spent fuel rack 32 and the fitting portions 52 and 72 of the damper devices 51 and 71 are formed in a T shape, the shape is not limited to this shape. Or any other shape.

  In each of the above-described embodiments, the spent fuel rack support structure of the present invention has been described as applied to a pressurized water reactor. However, it can also be applied to a boiling water reactor (BWR), It may be applied to any nuclear reactor.

DESCRIPTION OF SYMBOLS 11 Reactor containment vessel 12 Pressurized water reactor 13 Steam generator 31 Spent fuel pool 32 Spent fuel rack 41 Cell storage part 42 Leg part 44 Notch part 51, 71 Damper device 52, 72 Fitting part 53, 73 Piston part 58 Magnetic fluid 78 Dilatant fluid

Claims (6)

In a spent fuel rack that has a cell storage part into which spent fuel can be inserted from above along the vertical direction, and is placed adjacent to the spent fuel pool with a predetermined gap,
The plurality of adjacent spent fuel racks are connected by a damper device.
A structure for supporting a spent fuel rack.   The spent fuel rack support structure according to claim 1, wherein upper portions of the plurality of spent fuel racks are connected to each other by the damper device.   3. The spent fuel rack support structure according to claim 1, wherein the damper device attenuates vibrations by movement of a fluid filled therein.   The spent fuel rack support structure according to claim 3, wherein the damper device damps vibrations by a dilatant fluid filled therein.   4. The spent fuel rack support structure according to claim 3, wherein the damper device attenuates vibration by magnetizing a magnetic fluid filled therein. 5.   6. The damper device according to claim 1, wherein each of the end portions in the longitudinal direction is detachably provided in the vertical direction with respect to the plurality of spent fuel racks adjacent to each other. Support structure for spent fuel rack.

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