JP2009098037A - Device and method for preventing sloshing overflow - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively prevent an overflow due to sloshing without lowering pool use efficiency, and to more effectively prevent the overflow of liquid in the pool or splash out of the pool even if the sloshing occurs. <P>SOLUTION: A frame is installed on the periphery of an opening formed on the upper surface of a vessel containing the liquid, and the frame is covered with a sheet overlaying the upper opening of the vessel. By sealing the periphery of the opening formed in the upper surface of the vessel, the sloshing overflow occurring upon an earthquake is held on in inner periphery of the sheet. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a sloshing overflow control device and a method thereof in a facility containing liquid such as a spent fuel storage pool.

  In a nuclear power plant or the like, spent fuel is stored in a fuel storage pool containing liquid. The fuel storage pool has a rectangular shape in plan view. Cooling water is stored in the fuel storage pool, and the upper surface forms a free water surface.

  A spent fuel rack for storing spent fuel assemblies is installed on the bottom surface of the fuel storage pool. In the fuel storage pool, the distance between the upper surface of the spent fuel rack and the water surface is set deeper than the length of the fuel assembly or the like so that the fuel assembly or the like can be moved underwater.

  In the fuel storage pool, as many fuel assemblies as possible are stored in the pool, the spent fuel rack is installed up to the vicinity of the pool side wall. For this reason, in the fuel storage pool, it is necessary to keep the upper part of the spent fuel rack open as a means for moving the fuel assemblies and the like.

  In addition, in order to move spent fuel, etc., an overhead crane or a fuel changer that is a dedicated fuel changer must be used. Therefore, weirs must be provided around the fuel storage pool, or floating roofs or I can't cover it.

  When a low-frequency external force such as an earthquake is applied to the container containing the liquid, a swing called sloshing occurs on the liquid surface in the container. When sloshing occurs due to an earthquake in the fuel storage pool installed in the building, there is a possibility that the pool water flows out beyond the side wall of the fuel storage pool. In fact, when the Niigata Chuetsu-oki earthquake occurred on July 16, 2007, this event caused pool water to flow over the pool sidewall.

As a prior art, in order to prevent sloshing, it has been proposed to install a flat plate under the water surface on the side wall of the fuel storage pool (see Patent Document 1).
JP-A-8-101296

  Since it is necessary to make it possible to move spent fuel, etc. above the fuel storage pool, as described above, when a flat plate is installed in the pool, the lower part of the flat plate installation portion of the pool can be used. Therefore, the utilization efficiency decreases. For this reason, conventionally, it has been difficult to prevent sloshing without reducing pool utilization efficiency.

  Moreover, in the method of making the flat plate movable, it is difficult to exert its effectiveness against sloshing generated by an earthquake or the like while the spent fuel or the like is moving above. Furthermore, it has been difficult to exert its effect on sloshing caused by a direct earthquake or an earthquake far exceeding the assumption.

  The present invention has been made in view of such circumstances, and it is possible to suppress overflow caused by sloshing without lowering the pool utilization efficiency. Even if sloshing occurs, liquid overflow in the pool or An object of the present invention is to provide a sloshing overflow prevention device and method that can more effectively prevent scattering to the outside.

  In order to achieve the above object, according to the present invention, a skeleton is installed around an opening formed in the upper surface of a container that contains a liquid, and a sheet that covers the upper surface opening of the container is put on the skeleton to cover the container. By sealing the periphery of the opening formed on the upper surface, the sloshing overflow generated at the time of an earthquake is retained on the inner peripheral side of the sheet.

  According to the present invention, it is possible to cover the fuel storage pool with a pressure-resistant and water-resistant sheet cover, and to determine the procedure for covering, and more effectively prevent overflow caused by sloshing without reducing the pool utilization efficiency. Even if sloshing occurs, it is possible to prevent the liquid in the pool from overflowing or splashing.

  Embodiments of a sloshing overflow prevention device and method according to the present invention will be described below with reference to the drawings.

[First Embodiment (FIG. 1)]
In this embodiment, a skeleton is installed around the upper surface opening of the fuel storage pool, which is a container for storing liquid, and a sheet covering the upper surface opening of the fuel storage pool is put on the skeleton to surround the upper surface opening of the fuel storage pool A sloshing overflow prevention device and method for stopping sloshing overflow occurring at the time of an earthquake on the inner peripheral side of the seat will be described.

  FIG. 1 is a longitudinal cross-sectional view showing a sloshing overflow prevention device in a fuel storage pool of a boiling water reactor facility according to this embodiment and a facility configuration for implementing the method.

  As shown in FIG. 1, a reactor well 3 is disposed above a reactor pressure vessel 2 installed in a reactor containment vessel 1, and a fuel for storing spent fuel is located on the side of the reactor well 3. A storage pool 4 and a device temporary pool (DS pool) 5 are arranged. A fuel storage rack 10 is installed at the bottom of the fuel storage pool 4.

  The upper surfaces of the reactor well 3, the fuel storage pool 4 and the DS pool 5 are used as an operating floor 6 as a work floor, and fuel movement or the like is performed exclusively on a rail 7 installed on the operating floor 6. A refueling machine 8 is mounted. A handrail 9 that partitions the work area is provided around the refueling machine 8.

  Under this configuration, the first framework 11 is installed on the operating floor 6 around the upper surface opening of the fuel storage pool 6. The frame 11 is for self-supporting the first sheet, and is constituted by a plurality of pillars arranged along the periphery of the fuel storage pool 4 having a rectangular shape in plan view, necessary reinforcing bars, and the like.

  Then, the frame 11 is covered with a sheet 12 that covers the upper surface opening of the fuel storage pool 4, and the periphery of the upper surface opening of the fuel storage pool 4 is sealed. In this case, the seat 12 is, for example, a portion that rises from the vicinity of the upper surface opening of the fuel storage pool 4 and a horizontal roof-shaped portion that covers the entire upper portion of the upper surface opening from the rising portion. And the sheet | seat 12 which covers the fuel storage pool 4 is set to the height of the bridge 13 of the fuel exchanger 8 or less. Thereby, installation of the sheet | seat 12 by an operator can be performed easily.

  Further, coupled with the frame 11 of the seat 12, a plurality of ropes 14 for supporting self-supporting are provided at the upper end position of the periphery of the seat 12, and these ropes 14 are connected to the anchors 15 on the operating floor 6.

  Further, the lower end of the seat 12 is bound at the fuel storage pool surface position of the operating floor 6 along the horizontal direction as shown by a thick broken line in FIG. 1 so as to be opened and closed by an airtight zipper 16.

  With the above configuration, when there is no work such as moving the fuel assembly, as shown in FIG. 1, the seat 12 is caused by the framework 11 for allowing the seat 12 to stand by itself and the tension of the rope 14 and the anchor 15. It is fixed to the upper part of the fuel storage pool 4.

  Therefore, even when sloshing occurs due to an earthquake or the like, and the sloshing wave height grows and climbs over the wall height on the fuel storage pool 4 side, overflow does not occur outside the range covered by the seat 12, Can be prevented.

[Second Embodiment (FIG. 2)]
In the present embodiment, for a facility including a container for storing a liquid and a work floor along the surface of the container, a framework around the opening formed on the upper surface of the container and the entire work floor is installed, A description will be given of a sloshing overflow prevention device and method for retaining sloshing overflow generated at the time of an earthquake on the inner peripheral side of the seat by covering the framework and a sheet covering the work floor and sealing the entire container and work floor.

  FIG. 2 is a longitudinal sectional view showing the equipment configuration for implementing the sloshing overflow prevention device and method in the fuel storage pool of the boiling water reactor equipment according to this embodiment. In FIG. 2, the same reference numerals as those in FIG. 1 are assigned to the same and common functional components as those in FIG.

  As shown in FIG. 2, in the present embodiment, the second seat 20 that includes the working range of the refueling machine 8, the airtight zipper 16 for connecting the operating floor 6 and the seat 20, and the seat 20 A second frame 11a for supporting the self-standing, a rope 14a for supporting the self-supporting of the seat 20 in combination with the frame 11a, and an anchor 15a for connecting the rope 14a to the operating floor 6. In the present embodiment and the following embodiments, the reactor pressure vessel 1 is opened for work in the reactor and the like, and the core portion 2a in the reactor pressure vessel 2 is shown.

  With such a configuration, when work such as movement of a fuel assembly or the like is performed using the fuel changer 8, the tension of the framework 11a for allowing the seat 20 to stand up, the rope 14a, and the anchor 15a is used. The seat 20 is fixed to the upper part of the fuel storage pool 4 including the working range of the fuel changer 8.

  Also according to the present embodiment, sloshing occurs due to an earthquake or the like, and the sloshing wave height grows, and even if the height of the fuel storage pool side wall is overcome, overflow does not occur outside the range covered with the seat 20, Can be prevented.

[Third Embodiment (FIG. 3)]
In the present embodiment, a sloshing overflow prevention device and method for allowing a work object to be taken in and out of the liquid surface from the upper part of the sheet through the opening, which has an opening that can be opened and closed, will be described. .

  In FIG. 3, the same reference numerals are given to the same or common functional components as in FIGS. 1 and 2, and the description of the overlapping configuration of those portions is omitted.

  As shown in FIG. 3, the present embodiment has an opening 17 at the top of the seat 20 and an airtight zipper for opening and closing the opening 17 with respect to the configuration of the second embodiment (see FIG. 2). 31. Other configurations are the same as those in the first embodiment and the second embodiment.

  In the above configuration, when a heavy object is moved from the fuel storage pool 4 or the like to the operating floor 6 or from the operating floor 6 to the fuel storage pool 4 or the like using an overhead crane (not shown), the seat 20 is moved by the zipper 31. The opening 17 provided in the upper portion of the sheet can be opened and moved through the opening 17, and the overflow of the overflow can be prevented outside the range covered with the sheet 20.

[Fourth Embodiment (FIG. 4)]
In the present embodiment, a sloshing overflow control apparatus and method for connecting a wind exhauster and a filter device to the inside of the seat, and exhausting the gas in the seat to the outside from the existing exhaust tower via these wind exhauster and filter device. Will be described. In FIG. 4, the same reference numerals are given to the same and common functional components as those in FIGS. 1, 2, and 3, and the description of the overlapping configuration is omitted.

  In the present embodiment, as shown in FIG. 4, a small exhaust fan 21 that can be moved to the configuration of the second embodiment (see FIG. 2), a pipe 22 for connecting the exhaust fan 21 and the seat 20, The movable filter 23 includes a movable small filter 23, a pipe 24 and an exhaust tower 26 for connecting the exhaust fan 21 and the filter 23, and a pipe 27 for connecting the exhaust tower 26 and the filter 23.

  In the above configuration, the exhaust fan 21 is operated to manage the negative pressure in the seat 20 during operations such as fuel replacement, and the exhaust of the exhaust fan 21 is routed through the pipe 22, the filter 23, the pipe 24, and the pipe 27. By exhausting from the exhaust tower 26, it is possible to reliably and significantly reduce the radiation emission at the time of a fuel handling accident due to the fall of heavy objects such as fuel assemblies during work such as fuel replacement. . Further, the overflow of the overflow can be prevented outside the range covered by the sheet 20.

[Fifth Embodiment (FIG. 5)]
In the present embodiment, the step of covering the periphery of the opening formed on the upper surface of the container that stores the liquid with the first sheet, the step of covering the entire work floor including the first sheet with the second sheet, and the second A sloshing overflow prevention device and a method thereof including a step of taking out the first sheet from the inside of the sheet to the outside and covering the entire work floor with only the second sheet will be described.

  In this embodiment, as shown in FIG. 5, it implements by the structure provided with the structure of 1st Embodiment and the structure of 3rd Embodiment. That is, the skeleton 11 is installed on the operating floor 6 around the upper surface opening of the fuel storage pool 6 shown in FIG. This frame 11 is for self-supporting the seat, and is composed of a plurality of pillars arranged along the periphery of the rectangular fuel storage pool 6 in plan view, and necessary reinforcing bars.

  Then, the frame 11 is covered with a sheet 12 that covers the upper surface opening of the fuel storage pool 4, and the periphery of the upper surface opening of the fuel storage pool 4 is sealed. In this case, the seat 12 is, for example, a portion that rises from the vicinity of the upper surface opening of the fuel storage pool 4 and a horizontal roof-shaped portion that covers the entire upper portion of the upper surface opening from the rising portion. The seat 12 covering the fuel storage pool 4 is set to be equal to or lower than the height of the bridge 13 of the fuel exchanger 8.

  Further, coupled with the frame 11 of the seat 12, a plurality of ropes 14 for supporting self-supporting are provided at the upper end position of the periphery of the seat 12, and these ropes 14 are connected to the anchors 15 on the operating floor 6. Further, the lower end of the seat 12 is bound at the fuel storage pool surface position of the operating floor 6 along the horizontal direction as shown by a thick broken line in FIG. 1 so as to be opened and closed by an airtight zipper 16.

  Further, as shown in FIG. 3, when a heavy object is moved from the fuel storage pool 4 or the like to the operating floor 6 or from the operating floor 6 to the fuel storage pool 4 or the like, the zipper 31 is provided on the upper portion of the seat 20. The opening 17 is opened so that movement can be performed through the opening 17.

  As a structure of 3rd Embodiment applied in this embodiment, the opening part 17 and the zipper 31 are provided in the upper part of the sheet | seat 20 similarly to 2nd Embodiment, 3rd Embodiment of the state which closed the zipper 31 Is the same as in the second embodiment. When the operation such as the fuel exchange is not performed, only the sheet covering the fuel storage pool 4 is applied as in the first embodiment.

  In addition, about the structure of those other than the above, in FIG. 5, the same code | symbol is attached | subjected to FIG.1, FIG.2, FIG.3 and FIG.

  When carrying out work such as refueling, the following work steps are carried out.

  (1) First, the zipper 31 of the sheet 20 is closed so as to include the configuration shown in the first embodiment. This state is the same as the state of the third embodiment.

  (2) The state of the first embodiment in the seat 20 is similar to the third embodiment in which the zipper 31 is closed after the state similar to the third embodiment is completed by closing the zipper 31. Solve.

  (3) After the sheet covering the fuel storage pool or the like has been completed with only the sheet 20 with the zipper 31 closed, the heavy load is operated by an overhead crane or the like (not shown) for work such as fuel change by the fuel changer 8 or the like. When moving to the floor 6, the zipper 31 is opened and the opening 17 is provided in the upper part of the seat 20. When work such as fuel replacement is completed, the following work steps are performed.

  (4) The state of the first embodiment is constructed in the state of the third embodiment in which the zipper 31 is closed.

  (5) After the state of the first embodiment is completed, the embodiment state in which the zipper 31 is closed is solved.

Through the above process, the sheet covering the fuel storage pool 4 and the like is in a state of only the sheet 12,
By being able to return to the initial state, it is possible to prevent the overflow of the overflow except for the area inside the seat 12 that is covered regardless of the presence or absence of work in the fuel storage pool.

Explanatory drawing which shows the sloshing overflow suppression apparatus by 1st Embodiment of this invention, and its method. Explanatory drawing which shows the sloshing overflow suppression apparatus by 2nd Embodiment of this invention, and its method. Explanatory drawing which shows the sloshing overflow suppression apparatus and its method by 3rd Embodiment of this invention. Explanatory drawing which shows the sloshing overflow suppression apparatus by 4th Embodiment of this invention, and its method. Explanatory drawing which shows the sloshing overflow suppression apparatus and its method by 5th Embodiment of this invention.

Explanation of symbols

1. Reactor containment vessel, 2. Reactor pressure vessel, 3. Reactor well, 4. Fuel storage pool, 5. DS pool, 6. Operating floor, 7. Rail, 8. Fuel changer, 9. Handrail. DESCRIPTION OF SYMBOLS 10 ... Fuel storage rack, 11 ... Frame, 20 ... Seat, 13 ... Bridge, 14 ... Rope, 15 ... Anchor, 16 ... Zipper 17 ... Opening, 21 ... Air exhauster, 22 ... Piping, 23 ... Filter, 24 ... Piping 25 pipe, 26 exhaust tower, 27 pipe, 31 zipper.

Claims (10)

A frame is installed around the opening formed on the upper surface of the container that contains the liquid, and a sheet that covers the upper surface opening of the container is put on the frame to seal the periphery of the opening formed on the upper surface of the container. The sloshing overflow prevention method characterized by stopping the sloshing overflow which generate | occur | produces at the time of an earthquake on the inner peripheral side of the said sheet | seat. For a facility including a container for storing a liquid and a work floor along the surface of the container, a framework is installed around the opening formed on the top surface of the container and on the work floor, and the container and A sloshing overflow prevention method characterized in that a sloshing overflow generated at the time of an earthquake is retained on an inner peripheral side of the seat by covering a sheet covering the work floor and sealing the container and the entire work floor. The sloshing overflow suppression method according to claim 2, wherein the sheet has an opening that can be opened and closed, and the work object can be taken in and out of the liquid surface from the upper part of the sheet through the opening. The sloshing overflow suppression method according to claim 2, wherein an exhaust fan and a filter device are connected to the inside of the seat, and the gas in the seat is exhausted to the outside from an existing exhaust tower via the exhaust fan and the filter device. The process according to claim 1, wherein the periphery of the opening formed on the upper surface of the container containing the liquid is covered with a first sheet, and the entire work floor including the first sheet is covered with a second sheet. And a step of taking out the first sheet from the inside of the second sheet to the outside and covering the entire work floor with only the second sheet. Suppression method. A sloshing overflow prevention device comprising: a frame installed around an opening formed on an upper surface of a container for storing liquid; and a sheet covering the frame and covering the upper surface opening of the container. A frame installed on the work floor along the periphery of the opening formed on the upper surface of the container for storing the liquid and the surface of the container, and a sheet covering the container and the work floor over the frame. Sloshing overflow control device. The sloshing overflow prevention device according to claim 7, wherein the sheet has an opening that can be opened and closed. The sloshing overflow prevention device according to claim 7, wherein an exhaust fan connected to the interior of the seat, a filter device connected to the exhaust fan, an exhaust tower connected to the filter device, and an exhaust tower. A first frame installed around an opening formed on the upper surface of a container that stores liquid, a first sheet that covers the first frame and covers the upper surface opening of the container, and stores the liquid A second frame installed around the opening formed on the upper surface of the container and on a work floor along the surface of the container; a second sheet covering the container and the work floor over the second structure; A sloshing overflow prevention device characterized by comprising:

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