JP4990308B2 - Sloshing and overflow prevention device for spent fuel storage pool - Google Patents

Description

  The present invention relates to a sloshing of a spent fuel storage pool and an overflow prevention device that are provided in a spent fuel storage pool and prevent sloshing of pool water and flooding caused by the sloshing.

  In spent fuel storage pools installed at nuclear power plants, sloshing in which pool water stored in the pool sways when subjected to impacts such as earthquakes, tsunamis, collisions of flying objects, and explosions. The phenomenon occurs. Depending on the degree of the sloshing phenomenon that occurs, pool water overflows the fuel replacement floor due to the rise in liquid level, and in the worst case, it overflows to the lower floor and damages equipment, facilities, etc. There is a risk of spilling out.

  Conventionally, as means for preventing pool water overflow due to the sloshing phenomenon, a fence-shaped overflow prevention jig is provided on a weir provided on the pool side (see, for example, Patent Document 1). A weir provided on the pool side and a convex plate fixed along the surface of the fuel replacement floor following this, a fence provided on the top of the weir in this convex plate, and provided on the pool side of the fence And a free side wall of the spent fuel storage pool including a connecting flooding member having one end fixed to a fence and the other end fixed to a fuel replacement floor (see, for example, Patent Document 2). A hinge fixed below the surface of the water, a flat plate having one end rotatably supported by the hinge, a cord having one end connected to the tip of the flat plate, and an actuator for winding and rewinding the cord (For example, see Patent Document 3.) It has been proposed. Further, as means for preventing overflow in a general liquid storage container, a flange fixed to the inner surface of the liquid storage container, a steel plate having one end rotatably connected to the flange via a hinge, and a liquid storage container (For example, refer patent document 4) etc. which consist of the spring member provided between the inner surface of this and a steel plate are proposed.

JP 2006-329799 A JP 2006-317230 A JP-A-8-101296 Japanese Patent Application Laid-Open No. 61-11385

  All of the conventional overflow prevention means described above are to fix the overflow prevention member to the pool (container). Therefore, it takes a lot of labor to install and requires work to modify the nuclear power plant. When applied to existing nuclear power plants, there is a problem that the approval of the supervisory authority is required and the procedure becomes complicated. Such a problem occurs every time repair or recovery is performed after installation.

  The present invention has been made to solve such problems of the prior art, and aims to improve the reliability of nuclear power plants by suppressing sloshing and overflow caused by sloshing as much as possible. To do.

  An object of this invention is to set it as the structure which can be installed or removed suitably along the outer wall in a spent fuel storage pool.

  An object of this invention is to set it as the structure which does not disturb the movable range of existing facilities, such as a fuel exchanger installed in the spent fuel storage pool of a nuclear power plant.

  An object of this invention is to set it as the structure which can be installed, without modifying the outer wall etc. in a spent fuel storage pool.

  An object of this invention is to set it as the structure which can be installed not only in a newly installed nuclear power station but in the existing nuclear power station.

In order to solve such problems, the present invention is firstly a sloshing and overflow prevention device for a spent fuel storage pool that is provided in a spent fuel storage pool and prevents the slosh of pool water and the overflow caused by the slosh. A float floating in pool water in the spent fuel storage pool, a cushion provided on one side of the float facing the outer wall of the spent fuel storage pool, and the cushion of the float When the float is floated on the pool water, it is attached to the surface opposite to the opposite surface, and a wave-dissipating plate in which the lower part is submerged in water and the upper part protrudes above the water surface is adjacent to the wave-dissipating plate. and a connecting means for connecting the two floats disposed in the float, weir or refueling tip is formed by the pool of the spent fuel storage pool And the configuration of including a hook that is engaged.

In this way, if the wave-dissipating plate is attached to the float and floats on the pool water, it is not necessary to fix the wave-dissipating plate to the outer wall of the spent fuel storage pool, the weir, the fuel replacement floor, etc. And removal can be performed easily. In addition, since the wave-dissipating plate is not fixed, it is not necessary to obtain special approval from the supervisory authority, and existing nuclear power plants can be installed and removed as appropriate. In addition, when the bottom of the wave-dissipating plate is submerged in water and the upper part protrudes above the water surface and this wave-dissipating plate is attached to the float via a damping material, sloshing occurs in the pool water. Moreover, since the energy can be absorbed by the damping material, the sloshing of the pool water can be quickly attenuated. Therefore, the overflow of pool water from the spent fuel storage pool can be prevented, and the reliability of the nuclear power plant can be improved. In addition, if the wave-dissipating plate is attached to the float and floated on the pool water, the movable range of existing equipment such as a fuel exchanger installed above the spent fuel storage pool will not be disturbed, and workability may be impaired. Absent. Furthermore, if the connecting means for connecting the two floats is provided, a large number of sloshing and overflow prevention devices can be arranged without gaps along the outer wall of the spent fuel storage pool. In addition, overflow from the spent fuel storage pool can be prevented. In addition, if the float has a hook that is engaged with a weir formed on the pool side of the spent fuel storage pool or a fuel replacement floor, the weight of the wave-dissipating plate is borne not only by the float but also by the hook. Therefore, the size of the float can be reduced.

The present invention is in the second, the sloshing and overflow prevention device of the first spent fuel storage pool, the wave-dissipating plate, the top is curved or inclined in a direction away from the float, the curved or inclined The lower part is arranged in the pool water so that the upper part protrudes above the free water surface of the pool water.

  According to such a configuration, the pool water that rushes toward the outer wall from the central portion of the spent fuel storage pool can be returned to the pool at the curved or inclined upper portion, so that even if a large sloshing occurs, a wave is generated. It is difficult to cross the wave-dissipating plate, and can prevent overflowing more effectively.

The present invention is the third, the sloshing and overflow prevention device of the first or second spent fuel storage pool, said coupling means engaging protrusion formed on one side of the float, the float It was made into the structure which consists of the engagement recessed part which can be engaged with the said engagement convex part formed in the other side surface.

  According to this configuration, the float itself can be provided with the engaging convex portion and the engaging concave portion capable of engaging with this, so that it is not necessary to prepare a special connecting means separately, and the sloshing and overflow of the spent fuel storage pool Prevention can be carried out easily and inexpensively.

  According to the present invention, since the wave-dissipating plate is attached to the float and floats on the pool water, it is not necessary to fix the wave-dissipating plate to the outer wall of the spent fuel storage pool, the weir, the fuel replacement floor, etc. It can be done easily. Moreover, since no work is required for installing the wave-dissipating plate, it is not necessary to obtain special approval from the supervisory authority, and the existing nuclear power plant can be installed and removed as appropriate. Furthermore, since the wave-dissipating plate is attached to the float and floats on the pool water, the movable range of the existing equipment such as a fuel exchanger installed above the spent fuel storage pool is not hindered.

It is principal part sectional drawing seen from the side direction of the sloshing and overflow prevention apparatus which shows the structure of the sloshing and overflow prevention apparatus which concerns on embodiment, and the installation state to a spent fuel storage pool. It is a perspective view which shows the connection structure of the float of the sloshing and overflow prevention apparatus which concerns on embodiment. It is principal part sectional drawing seen from the front direction of the sloshing and overflow prevention apparatus which shows the installation state to the spent fuel storage pool of the sloshing and overflow prevention apparatus which concerns on embodiment. It is principal part sectional drawing which shows the effect of the sloshing and overflow prevention apparatus which concerns on embodiment.

  Hereinafter, the sloshing and overflow prevention device concerning an embodiment is explained with reference to drawings.

  As shown in FIG. 1, the sloshing and overflow prevention device 1 according to the present embodiment faces a float 2 that floats in pool water B in the spent fuel storage pool A and an outer wall C of the spent fuel storage pool A. The buffer material 3 provided on one side of the float 2, the wave-dissipating plate 5 attached to the surface of the float 2 opposite to the surface on which the buffer material 3 is provided via the damping material 4, and one end of the float 2 And a hook 6 engaged with a fuel replacement floor D formed on the pool side of the spent fuel storage pool A at the other end. In FIG. 1, symbol E is the free surface of the pool water B, symbol F is the spent fuel stored in the spent fuel storage pool A, symbol G is installed in the fuel replacement floor D, and the spent fuel storage pool. A fuel exchanger spanned above the opening of A is shown.

  The float 2 is formed in a hollow box shape with a metal material excellent in corrosion resistance such as stainless steel, and is filled with a gas or solid having a specific gravity lower than that of the pool water B as needed. As shown in FIG. 2, a substantially cylindrical engagement convex portion 11 is formed on one side of the float 2, and the other side is engaged with a C-shaped cross section that can be detachably engaged. A recess 12 is formed. These engagement convex part 11 and engagement concave part 12 are used as a connection means in the case of connecting a plurality of sloshing and overflow prevention devices 1 and, as shown in FIG. Of the sloshing and overflow prevention device 1, the engagement protrusion 11 of the float 2 provided in the other sloshing and overflow prevention device 1 in the engagement recess 12 of the float 2 provided in one sloshing and overflow prevention device 1. By engaging, any number of sloshing and overflow prevention devices 1 can be connected. Therefore, by connecting the necessary number of sloshing and overflow prevention devices 1, the sloshing and overflow prevention devices 1 can be arranged without gaps along the outer wall C of the spent fuel storage pool A as shown in FIG. 3. . At the time of removal, each sloshing and overflow prevention device 1 can be made into a single unit by releasing the engagement between the engagement convex portion 11 and the engagement concave portion 12.

  The buffer material 3 is provided to prevent the float 2 from directly colliding with the outer wall C of the spent fuel storage pool A due to the sloshing of the pool water B, and the float 2 and the outer wall C being damaged. Formed by.

  The damping material 4 absorbs wave energy of the pool water B due to sloshing, and is constituted by a coil spring having an elastic modulus capable of absorbing the maximum wave energy assumed.

  The wave-dissipating plate 5 suppresses sloshing of the pool water B, and as shown in FIG. 1, the upper portion 5a is curved in a direction away from the float 2, and the curved upper portion 5a is the pool water. It protrudes above the free water surface E of B, and it arrange | positions so that the flat lower part 5b may be immersed in the pool water B. The shape of the wave-dissipating plate 5 is not limited to that shown in FIG. 1. For example, the entire wave-dissipating plate 5 may be formed in a flat plate shape, or an inclined surface that is inclined in a direction separating the upper portion 5 a from the float 2. It can also be.

  The hook 6 is supplementarily provided when the buoyancy of the float 2 is insufficient, and can be omitted when the buoyancy of the float 2 is sufficient. In the example of FIG. 1, the tip of the hook 6 is engaged with the fuel replacement floor D. However, when a weir is provided on the pool side (see Patent Documents 1 and 2), the weir It is also possible to engage with the upper and side surfaces.

  Since the sloshing and overflow prevention device 1 of the present example has the above-described configuration, when sloshing occurs in the pool water B and the wave-dissipating plate 5 is pressed toward the pool side by wave energy, as shown in FIG. The damping material 4 is elastically deformed to absorb wave energy, and sloshing is suppressed. Moreover, since the upper part of the wave-dissipating plate 5 is curved to the pool side, the sloshing and overflow prevention apparatus 1 of this example can collide the wave that has been pushed against the wave-dissipating plate 5 and return it to the pool side, and the wave is extinguished. It is difficult to get over the wave plate 5. Therefore, overflow to the fuel replacement floor D can be prevented, and damage to equipment and facilities arranged on the lower floor can be prevented.

  Moreover, since the sloshing and overflow prevention apparatus 1 of this example attaches the wave-dissipating plate 5 to the float 2 and floats on the pool water B, the wave-dissipating plate 5 is attached to the outer wall C of the spent fuel storage pool A and the fuel replacement floor D. It is not necessary to fix it to the weir, etc., and it can be easily installed and removed, and it is not necessary to obtain special approval from the supervisory authority. be able to. Further, since the wave-dissipating plate 5 is attached to the float 2 and floats on the pool water B, the wave-dissipating plate 5 does not protrude above the fuel replacement floor D of the spent fuel storage pool A, and the spent fuel storage pool A The movable range of the existing equipment such as the fuel exchanger G installed above is not disturbed, and workability is not impaired. Furthermore, since the connection convex part 12 was formed in the both sides of the float 2, the required number of sloshing and the overflow prevention apparatus 1 can be connected suitably. Therefore, it is possible to arrange a large number of sloshing and overflow prevention devices 1 along the outer wall C of the spent fuel storage pool A without gaps, and to prevent overflow from the spent fuel storage pool A regardless of the direction of occurrence of sloshing. Can be prevented.

  Further, the sloshing and overflow prevention device 1 of the present example includes the hook 6 in the float 2 and engages the float 2 with the fuel replacement floor D. Therefore, the weight of the wave-dissipating plate 5 is not limited to the float 2 but by the hook 6. The float 2 can be reduced in size.

  The present invention can be applied to a spent fuel storage pool of a nuclear power plant in which sloshing of pool water and overflow resulting therefrom are problematic.

DESCRIPTION OF SYMBOLS 1 Sloshing and overflow prevention apparatus 2 Float 3 Buffer material 4 Damping material 5 Wave-dissipating plate 6 Hook 11 Engaging convex part 12 Engaging concave part A Spent fuel storage pool B Pool water C Outer wall C of spent fuel storage pool
D Fuel replacement floor E Free water surface of pool water F Spent fuel G Refueling machine

Claims (3)

A spent fuel storage pool sloshing and overflow prevention device provided in a spent fuel storage pool to prevent slosh of pool water and overflow caused by slosh,
A float that floats in pool water in the spent fuel storage pool, a cushioning material provided on one side of the float that faces an outer wall of the spent fuel storage pool, and a surface on which the cushioning material of the float is provided It is attached to the opposite side of the surface through a damping material. And connecting means for connecting the two floats ,
The spent fuel storage pool sloshing and overflow prevention device , wherein the float includes a weir or a hook that is engaged with a fuel replacement floor at a tip of the float on the pool side of the spent fuel storage pool . The wave-dissipating plate is curved or inclined in a direction away from the float, and the lower part is disposed in the pool water so that the curved or inclined upper part protrudes above the free water surface of the pool water. The sloshing and overflow prevention device of the spent fuel storage pool according to claim 1 .   The connecting means includes an engaging convex portion formed on one side surface of the float and an engaging concave portion formed on the other side surface of the float that can engage the engaging convex portion. The sloshing and overflow prevention device of the spent fuel storage pool according to any one of claims 1 and 2.

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