JP2013040871A - Nuclear fuel storage rack - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a nuclear fuel storage rack including a vibration control structure which is capable of reducing a slide amount in a horizontal direction.SOLUTION: A nuclear fuel storage rack 1A which is installed in water in a storage pit 100 in a state of storing therein an assembly of nuclear fuel W includes: a rack body 11 in which the nuclear fuel W is stored; a supporting leg part 18 which is provided under the rack body 11 and is movable in a horizontal direction relatively to a storage pit bottom surface 100a; and a universal joint 16A which is interposed between the rack body 11 and the supporting leg part 18 and connects the rack body 11 to the supporting leg part 18 so as to allow the rack body 11 to swing around at least one axial line extending in the horizontal direction.

Description

  The present invention relates to a nuclear fuel storage rack that is stored in a state where a nuclear fuel assembly is housed in water in a storage pit of a nuclear fuel storage facility.

  Spent nuclear fuel (spent nuclear fuel rods) generated at a nuclear power plant is stored and stored in a nuclear fuel storage facility. At this time, spent nuclear fuel is stored in a vertical cell of a nuclear fuel storage rack in a state of being stored in a square tube as a nuclear fuel assembly and stored in a storage pit of the nuclear fuel storage facility. Water is stored in the storage pit. By storing the nuclear fuel storage rack and the nuclear fuel assembly in water, the decay heat is cooled and kept below the criticality, and radiation is shielded. .

  For example, as disclosed in Patent Document 1, a nuclear fuel storage rack is fixed to a side wall of a storage pit via a support, and is stored in a state of being supported by the support and the storage pit. When the nuclear fuel storage rack is fixed in the storage pit in this way, it is possible to obtain a certain level of response reduction effect due to the fluid addition attenuation effect of water when an earthquake occurs. However, if the support load increases during a major earthquake, the nuclear fuel storage rack may not be supported.

  On the other hand, for example, Patent Document 2 proposes a nuclear fuel storage rack that is not fixed to the side wall or bottom of the storage pit and is put into practical use. This nuclear fuel storage rack is slidably mounted on the bottom surface of the storage pit, and absorbs the horizontal force acting upon the occurrence of an earthquake by sliding the nuclear fuel storage rack together with the effect of adding water to the fluid.

Japanese Patent Laid-Open No. 62-190494 JP 2003-75581 A

  However, in the nuclear fuel storage rack of Patent Document 2 described above, when a greater horizontal force is applied due to the occurrence of a large earthquake or the like, the sliding range of the nuclear fuel storage rack becomes large and collides with the side wall of the storage pit. The nuclear fuel storage rack may be damaged.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a nuclear fuel storage rack capable of suppressing the amount of sliding in the horizontal direction.

In order to solve the above problems, the present invention employs the following means.
That is, a nuclear fuel storage rack according to the present invention is a nuclear fuel storage rack installed in water in a storage pit in a state in which an assembly of nuclear fuel is stored, the rack main body storing the nuclear fuel, and the rack main body Provided between the rack main body and the base, and extending the rack main body in the horizontal direction relative to the base. And a rotation support portion that is pivotably connected around at least one axis.

  In such a nuclear fuel storage rack, when receiving a horizontal force due to an earthquake or the like, the base part slides in the horizontal direction with respect to the floor surface. Further, at the time of sliding, the rotating support portion swings around the axis, so that the rack body connected to the rotating support portion swings. Therefore, the horizontal force due to an earthquake or the like can be converted into two forces, the base sliding force and the rack body swinging force. In other words, part of the sliding force can be transferred to the swinging force, and the sliding force of the base can be reduced.

  Moreover, the said rotation support part of the nuclear fuel storage rack which concerns on this invention may have the spherical body which connects the said rack main body so that rocking | fluctuation is possible around all the axial lines extended in a horizontal direction with respect to the said base.

  By such a sphere, the rack body can be swung around all axes in the horizontal direction, so that the horizontal force due to an earthquake or the like can be more effectively converted into a swinging force, and by reducing the sliding force acting on the base, The amount of sliding of the base can be suppressed.

Further, the rotating support portion of the nuclear fuel storage rack according to the present invention includes a first shaft member that connects the rack body so as to be swingable around a first axis extending in a horizontal direction with respect to the base portion;
The rack body may include a second shaft member connected to the base portion so as to be swingable about a second axis that is orthogonal to the first axis and extends in the horizontal direction.

  By the first shaft member and the second shaft member, the rack body can swing around two axes orthogonal to the first axis and the second axis, and the horizontal force due to an earthquake or the like can be effectively converted into a swing force, By reducing the sliding force acting on the base, it is possible to suppress the sliding amount of the base.

  Moreover, the nuclear fuel storage rack according to the present invention may include an elastic member that is interposed between the base and the rack body and connects the base and the rack body.

  By such an elastic member, when a horizontal force due to an earthquake or the like acts and the rack body swings, the swinging force is absorbed while the sliding amount of the base is maintained, and the rack body and the base come into contact with each other and the shock is applied. Can be prevented. In addition, the swing can be restored and the rack body can be prevented from standing still in a tilted state. Therefore, the nuclear fuel accommodated in the rack body can be held more stably.

  Furthermore, you may provide the damping member which is interposed between the said base and the said rack main body, and connects these bases and a rack main body.

  With such a damping member, when the rack body swings, the swinging force can be absorbed while the sliding amount of the base is maintained, and the swinging amount can be attenuated. Therefore, the nuclear fuel accommodated in the rack body can be held more stably.

  You may provide the shock absorbing material interposed between the said base and the said rack main body.

  With such a cushioning material, when the rack body swings, it is possible to buffer the impact generated between the rack body and the base while maintaining the sliding amount of the base, and to suppress the swinging amount. Become. Therefore, the nuclear fuel accommodated in the rack body can be held more stably.

  According to the nuclear fuel storage rack of the present invention, it is possible to reduce the amount of sliding by converting a horizontal force due to an earthquake or the like into a sliding force and a swinging force.

It is the figure which has arrange | positioned the nuclear fuel storage rack which concerns on 1st embodiment of this invention in the storage pit. It is a figure which shows the rack for nuclear fuel storage which concerns on 1st embodiment of this invention. It is a figure which shows the rack for nuclear fuel storage which concerns on 2nd embodiment of this invention. It is a figure which shows the rack for nuclear fuel storage which concerns on 3rd embodiment of this invention. It is a figure which shows the rack for nuclear fuel storage which concerns on 4th embodiment of this invention.

Hereinafter, the nuclear fuel storage rack 1A according to the first embodiment of the present invention will be described.
As shown in FIG. 1, the nuclear fuel storage rack 1A stores, for example, spent nuclear fuel W generated at a nuclear power plant in water in a storage pit 100 of the nuclear fuel storage facility.

  As shown in FIG. 2, the nuclear fuel storage rack 1 </ b> A includes a rack main body 11 that stores the nuclear fuel W, and a vibration damping device 12 that is provided at a lower portion of the rack main body 11 and controls the swing of the rack main body 11. Yes.

  The rack body 11 is a box-shaped steel container whose outer shape is a rectangular parallelepiped, and is disposed in water with the nuclear fuel W contained therein.

Next, the vibration damping device 12 will be described.
The vibration damping device 12 includes an upper base plate 13 installed at the lower portion of the rack body 11, a universal joint (rotating support) 16A installed at the lower portion of the upper base plate 13, and a spring provided on the outer side in the horizontal direction of the universal joint 16A. (Elastic member) 15, lower base plate 17 provided below universal joint 16 </ b> A and spring 15, and support leg portion 18 provided below lower base plate 17.

The upper base plate 13 is a member having a rectangular flat plate shape with the horizontal direction as the longitudinal direction, and supports the rack body 11 from below. And the dimension of the horizontal direction of the upper base board 13 corresponds with the dimension of the horizontal direction of the rack main body bottom face 11a.
A plurality of connecting plates 14 are provided on the side of the upper base plate 13 and the rack main body 11 facing in the horizontal direction, and the upper base plate 13 and the rack main body 11 are coupled by the connecting plate 14.

  The universal joint 16A includes a spherical body 21, an upper holding member 22 that sandwiches the spherical body 21 from above, and a lower holding member 23 that sandwiches the spherical body 21 from below. The universal joint 16 </ b> A is disposed at the center of the upper base plate 13, and the surface facing the upper side of the upper holding plate 22 is coupled to the surface facing the lower side of the upper base plate 13. The downward facing surface is coupled to the upward facing surface of the lower base plate 17. By such a universal joint 16A, the upper base plate 13 and the rack main body 11 can swing around all axes extending in the horizontal direction with the lower base plate 17 as a reference.

  The spring 15 is a coil spring set to a predetermined elastic coefficient according to the weight of the rack body 11 containing the nuclear fuel W, and a plurality of springs (in this embodiment, the upper base plate 13 and the lower base plate are arranged around the universal joint 16A). 17 is provided at the corner portion 17, the upper end portion is coupled to the upper base plate 13, and the lower end portion is coupled to the lower base plate 17.

  The lower base plate 17 is a member having a rectangular flat plate shape with the horizontal direction as the longitudinal direction, similar to the upper base plate 13. In this embodiment, the horizontal dimension of the lower base plate 17 is the upper base plate 13 and the bottom surface of the rack body. It corresponds to the horizontal dimension of 11a.

  The support leg 18 is a substantially columnar member having a plurality of (four in the corner portions of the lower base plate 17 in the present embodiment) provided so as to protrude from the surface facing the lower side of the lower base plate 17 and having a vertical direction as an axis. is there. And this support leg part 18 is mounted in the state which can slide to a horizontal direction with respect to the storage pit bottom face (floor surface) 100a.

  In such a nuclear fuel storage rack 1A, when receiving a large horizontal force due to an earthquake or the like, the support leg 18 slides in the horizontal direction with respect to the storage pit bottom surface 100a. Further, the upper base plate 13 and the rack main body 11 swing with respect to the lower base plate 17 by the universal joint 16A. That is, a horizontal force due to an earthquake or the like is converted into two forces, a sliding force of the support leg 18 and a swinging force of the upper base plate 13 and the rack body 11. At this time, as compared with the case where all of the horizontal force is converted into the sliding force, a part of the horizontal force can be converted into the swinging force, and the sliding force acting on the support leg portion 18 can be reduced. be able to.

  Further, due to the sliding of the support leg 18, a frictional force acts between the surface facing the lower side of the support leg 18 and the storage pit bottom surface 100 a to consume the sliding power. Further, since the swinging force is absorbed by the spring 15 and the swinging is restored, the swing can avoid an impact caused by the contact between the rack main body 11 and the lower base plate 17, and the rack main body can stand still in a tilted state. Can also be avoided.

  Further, the upper base plate 13 and the rack main body 11 are coupled by a connecting plate 14. When the nuclear fuel storage rack 1 </ b> A is installed in the storage pit 100, the rack main body 11 and the vibration damping device 12 are installed integrally. be able to.

In the nuclear fuel storage rack 1A of the present embodiment, the horizontal force due to an earthquake or the like can be converted into the sliding force of the support leg 18 and the swinging force of the upper base plate 13 and the rack body 11, so that the amount of sliding by reducing the sliding force is reduced. Can be suppressed. The sliding force is consumed by the frictional force. As a result, the nuclear fuel storage rack 1A can be prevented from colliding with the side wall of the storage pit 100 and being damaged.
Further, the spring 15 can absorb and restore the oscillation, and the nuclear fuel W inside can be stably held.
Further, by installing the rack body 11 and the vibration damping device 12 together, it is possible to save time and labor when installing the nuclear fuel storage rack 1A in the storage pit 100.

  Note that the universal joint 16A of the present embodiment can be swung around all the axes extending in the horizontal direction by the sphere 21. However, the universal joint 16A is not limited to the sphere 21, and for example, the upper base plate 13 using a hemispherical member. Either the side or the lower base plate 17 side may be fixed and the other may be in a swingable state. Moreover, a simple convex part may be provided so as to protrude from the upper base plate 13 and the lower base plate 17, and may be swingable.

Next, the nuclear fuel storage rack 1B according to the second embodiment will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment, and detailed description is abbreviate | omitted.
The universal joint 16B has a first pin (first shaft member) 31 that can swing around a first axis that extends in the horizontal direction, and a first pin that can swing around a second axis that extends in the horizontal direction and is orthogonal to the first axis. It has two pins (second shaft member) 32.

  Furthermore, the universal joint 16B includes an upper holding member 33 that holds the first pin 31 from above, an intermediate holding member 34 that holds the first pin 31 from below and the second pin 32 from above, and the second pin 32 below. And a lower holding member 35 sandwiched therebetween.

That is, the universal joint 16B is configured from the upper side in the order of the upper holding member 33, the first pin 31, the intermediate holding member 34, the second pin 32, and the lower holding member 35.
Further, the surface facing upward of the upper holding member 33 is coupled to the surface facing downward of the upper base plate 13, and the surface facing downward of the lower holding member 35 is coupled to the surface facing upward of the lower base plate 17. Yes.

  In such a nuclear fuel storage rack 1B, as in the first embodiment, when receiving a large horizontal force due to an earthquake or the like, the support leg 18 slides in the horizontal direction with respect to the storage pit bottom surface 100a. Furthermore, the upper base plate 13 and the rack main body 11 swing around the first axis and the second axis with respect to the lower base plate 17 by the universal joint 16B. That is, since the horizontal force due to an earthquake or the like is converted into two forces, the sliding force of the support leg 18 and the swinging force of the upper base plate 13 and the rack body 11, it is compared with the case where all the horizontal forces are converted into the sliding force. As a result, a part thereof can be converted into a swinging force, and the sliding force acting on the support leg 18 can be reduced.

  As the support leg 18 slides, a frictional force acts between the surface facing the lower side of the support leg 18 and the storage pit bottom surface 100a to consume the sliding power.

In the nuclear fuel storage rack 1B of the present embodiment, the horizontal force due to the earthquake can be converted into the sliding force and the swinging force, and the sliding amount can be suppressed by reducing the sliding force. The sliding force is consumed by the frictional force. As a result, it is possible to prevent the nuclear fuel storage rack 1B from colliding with the side wall of the storage pit 100 and being damaged.
Further, as in the first embodiment, the nuclear fuel W inside can be stably held by the spring 15, and the rack body 11 and the vibration damping device 12 are integrally installed, whereby the nuclear fuel storage rack 1 </ b> B is stored in the storage pit. It is possible to save time and labor when installing in 100.

The upper and lower order of the first pin 31 and the second pin 32 is not limited to the case of the present embodiment, and the first pin 31 may be provided below the second pin 32.
Furthermore, the axis of the first pin 31 and the axis of the second pin 32 are not limited to being orthogonal to each other, and they may not be the same axis.

In this embodiment, the rack body 11 and the upper base plate 13 can be swung by the two pins of the first pin 31 and the second pin 32. However, a plurality of axes provided in the horizontal direction by providing a plurality of pins. It can also be made to swing around.
Further, instead of the plurality of pins, the rack body 11 and the upper base plate 13 may be swingable by a single pin having the same configuration as the first pin 31 or the second pin 32, that is, around at least one axis. It is only necessary to be able to swing.

Next, a nuclear fuel storage rack 1C according to a third embodiment will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment, and detailed description is abbreviate | omitted.
A plurality of nuclear fuel storage racks 1 </ b> C are provided between the upper base plate 13 and the lower base plate 17 in the horizontal direction outside the spring 15, that is, closer to the corners of the upper base plate 13 and the lower base plate 17 (in this embodiment, the upper base plate 13. And it differs from 1st embodiment by the point provided with the damper 41 (attenuation member) provided in the corner part of the lower base plate 17).

  The damper 41 is, for example, an oil damper or the like, and attenuates the swing of the upper base plate 13 and the rack body 11.

  In such a nuclear fuel storage rack 1C, the horizontal force due to an earthquake or the like can be converted into the sliding force of the support leg 18 and the swinging force of the upper base plate 13 and the rack body 11 as in the first embodiment. It is possible to suppress the sliding amount by reducing the sliding power.

  Further, the spring 15 absorbs the swing force and restores the swing, and the damper 41 attenuates the swing. Therefore, it is possible to suppress the swing amount without increasing the sliding amount of the support leg 18, and the nuclear fuel W accommodated in the rack body 11 can be protected even if a larger horizontal force is applied.

  In the nuclear fuel storage rack 1 </ b> C of the present embodiment, it is possible to suppress the sliding amount and the swing amount by the damper 41, and prevent the nuclear fuel storage rack 1 </ b> C from colliding with the side wall of the storage pit 100 and being damaged. In addition, the contained nuclear fuel W can be held more stably.

Next, a nuclear fuel storage rack 1D according to a fourth embodiment will be described with reference to FIG.
In addition, the same code | symbol is attached | subjected to the component similar to 1st embodiment, and detailed description is abbreviate | omitted.
A plurality of nuclear fuel storage racks 1D are provided between the upper base plate 13 and the lower base plate 17 in the horizontal direction outside the spring 15, that is, closer to the corners of the upper base plate 13 and the lower base plate 17 (in this embodiment, the upper base plate 13). This is different from the first embodiment and the third embodiment in that a cushioning material 51 is provided which is provided at four corner portions and four corner portions of the lower base plate 17.

  The cushioning material 51 is an elastic member such as rubber, for example. The cushioning material 51 is an upper cushioning material 51 provided so as to protrude downward from the upper base plate 13 via the pedestal 50 and upward from the lower base plate 17 via the pedestal 50. And a lower cushioning material 51 provided so as to protrude. The upper cushioning material 51 and the lower cushioning material 51 face each other.

  In such a nuclear fuel storage rack 1D, the horizontal force due to an earthquake or the like can be converted into the sliding force of the support leg 18 and the swinging force of the upper base plate 13 and the rack body 11 as in the first embodiment. It is possible to suppress the sliding amount by reducing the sliding power. As a result, the nuclear fuel storage rack 1D can be prevented from colliding with the side wall of the storage pit 100 and being damaged.

  Further, the spring 15 absorbs the swinging force and restores the swinging, and also absorbs the shock and suppresses the swinging amount when the buffer material 51 swings. Accordingly, it is possible to reduce the swing amount and absorb the impact without increasing the sliding amount of the support leg 18, and it is possible to protect the nuclear fuel W accommodated in the rack body 11 even if a larger horizontal force is applied. .

  According to the nuclear fuel storage rack 1D of the present embodiment, the amount of swing and the shock absorption at the time of swing can be suppressed by the buffer material 51 as well as the amount of sliding. Therefore, the nuclear fuel storage rack 1D can be prevented from colliding with the side wall of the storage pit 100 and being damaged, and the stored nuclear fuel W can be more stably held.

The embodiment of the present invention has been described in detail above, but some design changes can be made without departing from the technical idea of the present invention.
For example, the spring 15 is not limited to a coil spring, and another member having a restoring force such as a plate spring or an air spring may be employed.

  Furthermore, in the above-described embodiment, the installation positions of the spring 15, the damper 41, and the buffer material 51 are the corners of the upper base plate 13 and the lower base plate 17. The case is not limited.

DESCRIPTION OF SYMBOLS 1A ... Nuclear fuel storage rack, 1B ... Nuclear fuel storage rack, 1C ... Nuclear fuel storage rack, 11 ... Rack main body, 11a ... Rack main body bottom surface, 12 ... Damping device, 13 ... Upper base plate, 14 ... Connection plate, 15 ... Spring, 16A ... Universal joint (rotating support), 16B ... Universal joint (rotating support), 17 ... Lower base plate, 18 ... Supporting leg, 21 ... Sphere, 22 ... Upper holding member, 23 ... Lower holding member, 31 ... First pin (first shaft member), 32 ... Second pin (second shaft member), 33 ... Upper holding member, 34 ... Intermediate holding member, 35 ... Lower holding member, 41 ... Damper (damping member) 50 ... Pedestal 51 ... Buffer material 100 ... Storage pit 100a ... Storage pit bottom (floor surface)

Claims (6)

A nuclear fuel storage rack installed in water in a storage pit in a state in which a nuclear fuel assembly is stored,
A rack body for storing the nuclear fuel;
A base that is provided below the rack body and is movable relative to the floor in a horizontal direction;
A nuclear fuel comprising: a rotating support portion interposed between the rack main body and the base portion and connected to the rack main body so as to be swingable about at least one axis extending in a horizontal direction with respect to the base portion. Storage rack.   2. The nuclear fuel storage rack according to claim 1, wherein the rotary support portion includes a sphere that connects the rack body so as to be swingable about all axes extending in a horizontal direction with respect to the base portion. The rotation support portion includes a first shaft member that swingably connects the rack body about a first axis extending in a horizontal direction with respect to the base portion;
2. The second rack member that connects the rack body to the base so as to be swingable about a second axis that is orthogonal to the first axis and extends in the horizontal direction. Rack for nuclear fuel storage.   The nuclear fuel storage rack according to any one of claims 1 to 3, further comprising an elastic member interposed between the base and the rack body to connect the base and the rack body.   The nuclear fuel storage rack according to any one of claims 1 to 4, further comprising a damping member interposed between the base and the rack main body to connect the base and the rack main body.   The nuclear fuel storage rack according to claim 1, further comprising a buffer material interposed between the base and the rack body.

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