JP2006317230A - Fence structure of fuel storage pool - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce possibility of overspill to lower stories and possibility of influence to important facilities on the lowermost story by suppressing or mitigating as much as possible, the overspill due to sloshing in a fuel storage pool in a nuclear power station. <P>SOLUTION: The structure comprises a weir 2 provided around the fuel storage pool 1 in the nuclear power station, a fuel exchange floor 3 provided at a lower arrangement than the weir around the weir, a projected plate 4 fixed along the surface of the weir and the fuel exchange floor and a fence 5 fixed at the top of the weir of the projected plate. To the fence 5, an overspill water suppression member 12, which consists of a sheet or a panel for suppressing overspilling outside the pool when the pool water level rises due to sloshing, is provided. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a fence structure of a fuel storage pool in a nuclear power plant, and more particularly, a fuel storage function that absorbs the impact of oscillating water when a sloshing occurs in the fuel storage pool water due to an earthquake and relaxes overflow. It relates to the fence structure of the pool.

  In a fuel storage pool installed at a nuclear power plant, a sloshing phenomenon occurs in the event of an earthquake, and the pool water may sway, and the pool water may overflow to the floor due to a rise in liquid level.

  If pool water rises and overflows to the floor, if it is below a certain amount, it will stay on the floor and will not overflow to the lower floor of the pool, and be stored in the drain sump tank on the lowest basement floor. It becomes.

  However, there is a possibility that this amount will be exceeded, and since the drain sump tank on the basement floor is small, it is impossible to deny the possibility of overflowing from the tank on the basement floor and affecting important facilities. .

In addition, as a prior art, a flat plate is installed in the vicinity of the liquid surface of a container for storing liquid, and the flat plate is supported by a support member so as to be rotatable and fixed (see, for example, Patent Document 1). A configuration including an assembly water tank in which a panel having a flange and a panel formed with a flange on one side of the four circumferences thereof, and a large number of projecting pieces provided on the inner surface of the side wall of the water tank (for example, see Patent Document 2) Has been proposed.
JP-A-8-101296 JP-A-10-152195

  As described above, in the prior art, measures are taken to prevent flooding by sloshing, such as weirs provided on the fuel replacement floor and by increasing the installation position of each device, but actively suppressing or mitigating sloshing. No measures have been taken. Therefore, since there is no active suppression and mitigation measures against sloshing, the possibility of affecting important facilities cannot be denied.

  The present invention has been made in view of such circumstances, and suppresses and mitigates the amount of overflow due to sloshing as much as possible, and may affect the possibility of overflowing to the lower floor and important facilities on the lowest basement floor. It is an object of the present invention to provide a fuel storage pool fence structure that can improve the reliability of a nuclear power plant by reducing the power consumption.

  The present inventor has improved the structure of a fence (handrail) installed around the spent fuel storage pool of a nuclear power plant so that the pool water swelled due to an earthquake, and the fuel has passed over the weir. We paid attention to alleviating the overflow caused by the so-called sloshing overflowing the replacement floor. In other words, the present inventors have conceived a configuration that absorbs the shock of the oscillating water when the sloshing of the fuel storage pool water due to the earthquake occurs and has a function of mitigating overflow.

  As means for mitigating or suppressing overflow due to sloshing, (1) means for suppressing the increase of the water level by attenuating the fluctuation energy of water, and (2) means for increasing the weir and reducing the amount of water to get over are considered. .

  The present invention proposes to mitigate and suppress overflow due to sloshing by providing both the functions (1) and (2) to the fence structure disposed around the pool.

  In other words, the fence structure of the present invention is mainly composed of a weir around the pool and a convex plate that matches the cross-sectional shape of the fuel replacement floor, and a fence fixed on the plate. Propose.

  It is desirable to attach a sheet or panel to the fence, and to project one end of the convex plate on the pool and provide a small hole for venting air.

  In the convex plate of the fence structure according to the present invention, it is not fixed to the inner surface of the fuel storage pool or the lining, but is fixed to the upper surface of the weir or the floor around the pool with a post-fixed anchor or the like. It is desirable to fix. Thereby, since the fence structure is cut off from the fuel storage pool, it can be handled not as a fuel storage facility but as equipment on the fuel replacement floor. In addition, it is desirable to provide an oblique connecting rod between the upper part of the fence and the fuel replacement floor so as to support the overflow load.

  The present invention has been made on the basis of the above knowledge. In the invention according to claim 1, the weir provided around the fuel storage pool in the nuclear power plant, and the weir around the weir. A fuel replacement floor provided in a low arrangement, a convex plate fixed along the surfaces of the weir and the fuel replacement floor, and a fence fixed on the top of the weir in the convex plate The fuel storage pool fence is characterized in that the fence is provided with an overflow mitigation member comprising a sheet or a panel for mitigating overflow to the outside of the pool when the pool water level rises due to sloshing. Provide structure.

  According to a second aspect of the present invention, the convex plate includes a fuel storage pool fence provided with a protruding portion for mitigating a water level that protrudes toward the fuel storage pool in an arrangement higher than the surface of the pool water. Provide structure.

  According to a third aspect of the present invention, there is provided the fuel storage pool fence structure according to the first aspect, wherein the overflow mitigating member is a flexible sheet or a metal or plastic panel.

  In the invention which concerns on Claim 4, the fence structure of the fuel storage pool which provided the connecting rod which receives the dynamic pressure by rocking water as a compression load between the upper part of the said fence and the said fuel replacement floor is provided.

  In the invention according to claim 5, a fuel storage pool in which an air vent hole for preventing negative pressure generation when swinging water is drawn is formed in a protruding portion of the convex plate toward the fuel storage pool. Provides a rail structure.

  In the invention which concerns on Claim 6, the said fence is divided structure along the outer edge of the said fuel storage pool, The fence structure of the fuel storage pool which can be installed and removed for every divided part is provided.

  According to the present invention, it is possible to alleviate overflow caused by sloshing of pool water at the time of an earthquake and to affect the possibility of overflow from the fuel replacement floor to the lower floor of the building and the important facilities on the lowest basement floor. Therefore, it is possible to improve the reliability of the nuclear power plant during an earthquake. Moreover, it is possible to easily install an existing power plant with a post-fixed anchor.

Hereinafter, an embodiment of a fence structure for a fuel storage pool according to the present invention will be described with reference to the drawings.
[First Embodiment (FIGS. 1 and 2)]
FIG. 1 shows a fence structure of a fuel storage pool according to a first embodiment of the present invention, and FIG. 2 shows a state during sloshing.

  As shown in FIG. 1, in the fence structure of the fuel storage pool 1 of the present embodiment, the weir 2 provided around the fuel storage pool 1 in the nuclear power plant, and the periphery of the weir 2 The fuel replacement floor 3 provided in a low arrangement, the convex plate 4 fixed along the surfaces of the weir 2 and the fuel replacement floor 3, and the top of the weir 2 in the convex plate 4 And a fence 5 fixed on the top.

  That is, this fence structure is composed of a convex plate 4 adapted to the cross-sectional shape of the weir 2 around the pool and the fuel replacement floor 3 and a fence 5 fixed on the convex plate 4. Is done. The convex plate 4 rises along the outer peripheral side surface of the weir 2 from the above-mentioned floor fixing portion 4a and the floor fixing portion 4a fixed to the upper surface of the fuel replacement floor 3 arranged around the weir 2. The rising part 4b, the top part 4c arrange | positioned in the form which covers the upper surface of the weir 2, and the drooping part 4c hanging down along the lining 6 of the inner peripheral side of the weir 2, ie, the pool inner surface, are provided from this top part 4c. Yes.

  Specifically, the on-floor fixing portion 4a of the convex plate 4 is fixed to the upper surface of the fuel replacement floor 3 by fixing it with a post anchor 7 as a fixing means. The rising portion 4b is fixed to the outer peripheral side surface of the weir 2 by fixing with a post-cast anchor 8, and is thereby fixed to the fuel replacement floor 3 side around the pool.

  In this way, in this embodiment, the convex plate 4 cuts the edge from the inner surface of the pool and the lining 6 and fixes to the upper surface and the outer side of the fuel replacement floor 3 and the weir 2 around the pool. It is fixed.

  In other words, the convex plate 4 is not fixed to the inner surface of the fuel storage pool 1 or the lining 6, and the post-cast anchors 7 and 8 are placed on the upper surface of the weir 2 or the fuel replacement floor 3 around the pool. For example, the hydraulic pressure load is fixed to the fuel replacement floor 3 side. Therefore, since the edge of the fence structure of the present embodiment is cut off from the fuel storage pool 1, it can be handled as equipment on the fuel replacement floor 3 instead of the fuel storage facility.

  Further, the convex plate 4 is provided with an overhanging portion 4e for increasing the water level that protrudes toward the fuel storage pool 1 in an arrangement higher than the surface of the pool water 9. That is, one end of the convex plate 4 protrudes on the pool, functions as a baffle plate that attenuates the rise in the water level, and is configured to alleviate the rise in the water level. As a result, the convex plate 4 is fixed to the upper surface and the outer side of the fuel replacement floor 3 and the weir 2 and fixed, and the end portion projects onto the pool, thereby mitigating the rise in water level due to sloshing. Functions as a damping device.

  In addition, an air vent hole 10 is formed in the projecting portion 4e of the convex plate 4 toward the fuel storage pool 1 to prevent the generation of negative pressure when the oscillating water is drawn. That is, the air vent hole 10 prevents the negative pressure from being generated when the oscillating water is drawn at the protruding portion of the convex plate 4 on the pool water 9.

  Further, the fence 5 is provided with an overflow mitigation member 12 made of a sheet for mitigating the overflow of the pool water 9 due to sloshing when the pool water 9 rises. This overflow mitigating member 12 is configured as a flexible sheet, thereby mitigating the outflow of the pool water 9 out of the pool when the water level rises due to sloshing.

  FIG. 3 shows a state when the water level rises due to sloshing. As shown in FIG. 2, a sheet is provided along the fence 5 so that the pool water 9 functions so as not to spill out of the pool when the water level rises due to sloshing. be able to.

  Further, a connecting rod 13 is provided between the upper part of the fence 5 and the fuel replacement floor 3 to receive the dynamic pressure of the oscillating water as a compression load.

  That is, in the case of fixing only the convex plate 4 as described above, there is a possibility that the pressure of the oscillating water cannot be fully resisted. Therefore, an oblique connection is made between the upper part of the fence 5 and the fuel replacement floor 3. A configuration is adopted in which the rod 13 is passed, the dynamic pressure is received by the compression of the connecting rod 13, and most of the dynamic pressure of the oscillating water is supported by the fuel replacement floor 3.

  The fence 5 has a divided structure along the outer edge of the fuel storage pool 1, and can be installed and removed by human power for each divided portion.

  As described above, according to the present embodiment, the amount of overflow due to sloshing is suppressed and mitigated as much as possible, and the possibility of overflowing to the lower floor and the possibility of affecting important facilities on the lowest basement floor is reduced. As a result, the reliability of nuclear power plants can be improved.

[Second Embodiment (FIG. 3)]
FIG. 3 shows a fence structure of the fuel storage pool 1 according to the second embodiment of the present invention. In the present embodiment, the same components as those in the first embodiment are denoted by the same reference numerals as those in FIG.

  The present embodiment is different from the first embodiment in that an overflow mitigation member 12 that mitigates the overflow of the pool water 9 due to sloshing provided in the fence 5 to the outside of the pool when the water level rises is made of a metal or plastic panel. It is in the point. The panel as the overflow mitigating member 12 is provided on the pool side surface of the fence 5 at substantially the same height as the fence 5, and is attached to the fence 5 via a connecting member 14.

  Even with such a configuration, similarly to the first embodiment, when the water level rises due to sloshing, the outflow of the pool water 9 to the outside of the pool can be mitigated.

[Other Embodiments]
In addition to the configuration of each of the embodiments described above, on the sheet or panel installed on the fence 5, a picture, an illustration, or a geometric pattern that leads to an image improvement of the power plant is drawn. It is desirable not to feel that it is a mitigation device.

The block diagram which shows the fence structure of the fuel storage pool by 1st Embodiment of this invention. Explanatory drawing which shows the effect | action at the time of sloshing by 1st Embodiment of this invention. The block diagram which shows the fence structure of the fuel storage pool by 2nd Embodiment of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Fuel storage pool 2 Weir 3 Fuel replacement floor 4 Convex type plate 5 Fence 6 Lining 7 Anchor 8 Anchor 9 Pool water 10 Air vent hole 12 Overflow mitigation member 13 Connecting rod 14 Connecting member

Claims (6)

A weir provided around a fuel storage pool in a nuclear power plant, a fuel replacement floor provided at a lower position around the weir, and along the surfaces of the weir and the fuel replacement floor A fixed convex plate and a fence fixed on the top of the weir on the convex plate, and the fence overflows outside the pool when the pool water level rises due to sloshing. A fuel storage pool fence structure, characterized in that an overflow mitigation member comprising a sheet or panel for mitigating water is provided. 2. The fuel storage pool fence structure according to claim 1, wherein the convex plate is provided with a protruding portion for mitigating a rise in water level that protrudes toward the fuel storage pool in an arrangement higher than the surface of the pool water. 2. The fuel storage pool fence structure according to claim 1, wherein the overflow mitigating member is a flexible sheet or a metal or plastic panel. The fuel storage pool fence structure according to claim 1, wherein a connecting rod is provided between the upper part of the fence and the fuel replacement floor to receive dynamic pressure due to oscillating water as a compression load. 2. The fuel storage pool fence structure according to claim 1, wherein an air vent hole for preventing negative pressure generation when rocking water is drawn is formed in a protruding portion of the convex plate toward the fuel storage pool side. . 2. The fuel storage pool fence structure according to claim 1, wherein the fence has a divided structure along an outer edge of the fuel storage pool, and can be installed and removed for each divided portion.

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