JP3448181B2 - Support equipment for spent fuel cooling and storage equipment - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear fuel storage facility for a nuclear reactor, and more particularly to a facility for cooling and storing so-called spent fuel that has undergone a predetermined combustion in a nuclear reactor.

[0002]

2. Description of the Related Art Spent fuel that has undergone a predetermined combustion in a light water reactor has a high radioactivity level and a large amount of decay heat generated,
It is stored in a cooling pond or a storage pool attached to the reactor plant until it does not hinder the convenience of handling such as transportation.
An example of a conventional storage facility for spent fuel used for such a purpose is shown in FIG. In the figure, the inner surface of the pit formed in the body of the concrete structure is lined with, for example, a stainless steel plate or the like, and a cooling water supply / discharge device, a cooling device, or the like is connected to this, and the storage pool 1 is Has been formed. In the drawing, the side wall on the front side of the storage pool 1 is shown as cut away, but the horizontal support plate 5 is arranged above and below the embedded plates 3 fixed to the side wall.
The rectangular rack cells 7 are connected and supported one by one, and have a plurality of insertion holes (described later) formed in the support plates 5 thereof.
Is inserted, and a fuel assembly which is a spent fuel is accommodated in the rack cell 7.

Details of the structure of each support plate 5 and its mounting structure are shown in FIG. In FIG. 10, the front two support plates 5 in FIG. 9 are omitted for simplicity of the drawing, and only the rear two support plates 5 are shown, but this is a lattice opening shape. It is a thick-walled flat plate made of stainless steel having a substantially square through hole 9 bored in a hole and a substantially rectangular connecting hole 11 formed along the outer edges of two sides. And the outer edges of the four sides of the upper and lower support plates 5 are
The lower end is vertically supported by a plurality of vertical stays 13 supported by the bottom of the storage pool 1. Each stay 1
3 is a support plate 5 as shown in particular in FIG.
Is equipped with fixing nuts 15 above and below the through part of
The height of the support plate 5 is adjusted and fixed so that the horizontality and the vertical distance of the support plate 5 are maintained. A holder 17 passing through the connecting hole 11 is interposed between the support plate 5 and the embedding plate 3, and the holder 17 is provided so as to project from the embedding plate 3, as shown in FIGS. It is fixed to the fixed plate 19. In this structure, the internal slot height of the holder 17 is larger than the wall thickness of the support plate 5 so that the holder 17 is relatively displaceable in the vertical direction. Further, since the holder 17 is not fixed to the support plate 5, the support 5 and hence the holder 17 are not fixed. It can be displaced relative to the embedded plate 3 in the horizontal direction within a practical range.

In the conventional storage facility having the above-mentioned structure, each fuel assembly, which is spent fuel, is stored and stored in the rack cell 7 one by one. The weight of the fuel assembly is directly stored in the bottom of the storage pool 1 together with the weight of the rack cell 7. And is supported by. Then, a horizontal load due to an earthquake or the like is transmitted to the support plate 5 via the rack cell 7, and is transmitted to and supported by the embedded plate 3 on the side wall orthogonal to the acting direction of the horizontal load via the holder 17 and the fixed plate 19. It The load is not transmitted to the side wall parallel to the acting direction of the horizontal load due to the relative displacement of the holder 17 and the support plate 5. While storing a large number of fuel assemblies, the temperature of the cooling water in the storage pool 1 rises within an allowable range, and the horizontal thermal expansion of the support plate 5 due to this temperature rise is caused by It is absorbed by the structure as shown in FIG. 14 and is not restrained from the side wall of the storage pool 1. That is, as shown in the figure, one support plate 5 is a fixed plate 19 and a holder 17 on an embedded plate on a side wall of the storage pool 1 which intersects.
Although it is supported in the horizontal direction by the horizontal direction, the direction of thermal expansion or relative displacement of the support plate 5 due to thermal expansion due to temperature rise can be decomposed in the direction of the white arrow, and the holders 17 arranged in the direction of the arrow are described above. Due to the structure, the relative displacement is allowed. The vertical thermal displacement of the support plate 5 is absorbed by the gap between the support plate 5 and the holder 17 described above. Therefore, excessive thermal stress does not occur in the support plate 5.

[0005]

In the spent fuel storage facility having the above structure, the inner size of the rack cell 7 is set so as to receive the fuel assembly to be accommodated without an excessive gap, and the rack cell 7 may be damaged by an earthquake or the like. Even if vibration occurs, the fuel assembly is held without causing any unfavorable movement. On the other hand, the interval between the rack cells 7 is set so that the neutrons emitted from the spent fuel do not become critical. That is, the gap between the inner surface of the rack cell and the fuel assembly is hardly changed in order to avoid physical interference, while the gap between the rack cells is nuclearly limited, but the constituent material of the rack cell has a neutron absorption capability. It has been proposed to realize a high density storage of spent fuel while satisfying nuclear restrictions instead of larger ones. In such a proposal, the distance between the rack cells is reduced and the number of fuel assemblies supported within a certain space volume, that is, the weight is increased, so that the required strength of the support plate is increased, while the rack cell 7 of the support plate 5 is increased. It becomes difficult to secure strength unless the material and wall thickness are changed because the dimension between them becomes small. For this reason, for high-density storage of spent fuel, it is essential to increase the thickness of the support plate, but this increases the amount of machining holes for rack cells, which increases the material cost and processing cost of the support plate. This will increase the manufacturing cost. Therefore, there is a demand for a high-density storage facility for spent fuel, which has a low manufacturing cost or an increase in cost as compared with conventional ones. Further, although the high-density storage of spent fuel is excellent in terms of volumetric use efficiency, there are limitations due to the constraint conditions for preventing criticality as described above. Therefore, if a preferable material having a higher neutron absorption capacity is realized in the future, further high-density type storage will be possible, and it may be required to modify the storage facility to increase the storage capacity. In such a case, in order to carry out the remodeling work in the air, it is necessary to move the storage fuel assembly to another facility and to drain a large amount of storage pool water. This requires equipment for that (the pool water is at risk of being radioactively contaminated and cannot simply be discarded). Therefore, there is a demand for a spent fuel storage facility that can be remodeled while cooling water is stretched in the storage pool and the storage fuel assembly is stored in the pool when the capacity is increased. The present invention has been made in view of the above circumstances and has been made to meet the needs, and it is an object of the present invention to provide a support device for a spent fuel cooling storage facility, which has a low manufacturing cost and is easily modified after installation. And

[0006]

In order to solve the above-mentioned problems, according to the present invention, a horizontal arrangement is provided in a storage pool filled with water, which defines a plurality of insertion holes arranged in a lattice opening shape. A support device for a spent fuel cooling and storage facility, which comprises a support structure and a rectangular tubular rack cell that is individually inserted into each of the insertion holes to receive and accommodate a fuel assembly, has a horizontal support. In the structure, a plurality of long girder members each having a plurality of notches formed side by side and a long beam member intersect each other, and the long girder member and both ends of the long beam member are combined. is configured by connecting to each other by the outer peripheral restraining plate, the height adjusting mechanism for fixing the horizontal support structure to the bottom surface of the storage pool is disposed outside the vertical projection plane of the horizontal support structure, the height adjustment mechanism screw member operable from vertically above It has. Furthermore, according to the invention
For example, it is arranged in a storage pool filled with water and has a lattice opening shape.
A horizontal support structure defining a plurality of through holes arranged,
The fuel assemblies are individually inserted into the through holes.
Used with a square tubular rack cell to store and store
The support device for fuel cooling and storage equipment is
Multiple long girders with multiple notches lined up on one side
The member and the long beam member are crossed and combined,
Both ends of the long girder member and the long beam member are connected to each other by an outer peripheral restraint plate.
Is configured by connecting to have, projecting arranged at intervals in the buried plate extending in the horizontal direction of the side wall of the storage pool
The integrated machining type support plate inserted in the rectangular cross-section holder attached to the multiple horizontal fixed plates
The comb connecting plate is cut remainder cut in the side wall direction, the side wall of the storage pool as a whole by bolting the horizontal connecting plate projecting from the outer peripheral constraining plate via <br/> connection plate of the horizontal support structure It is characterized by being supported by.

[0007]

Embodiments of the present invention will be described below with reference to the accompanying drawings. First, referring to FIG. 1, the horizontal support structure 20 of the spent fuel cooling storage facility is configured as a lattice-like structure as described later. Specifically, a plurality of beam members or upper strips 21 and a plurality of girder members or lower strips 23
Are assembled at right angles to each other. The situation is shown in the partial perspective view of FIG. As is apparent from FIG. 2, the upper strip 21 and the lower strip 23 have notches or slots 21a and 23a having substantially the same width as the thickness of the mating side at the intersections, respectively. The two are meshed with each other so that they do not fall down, and they are securely combined and welded at appropriate places to prevent mutual separation. Although the overall shapes of the upper strip 21 and the lower strip 23 are shown in the exploded view of FIG. 3, as can be seen from the figure, the upper strip 21 and the lower strip 23 are relatively narrow and long. It is a plate material. Again referring to FIG. 1, the upper strip 21 and the lower strip 2 assembled in a grid pattern as described above.
Both ends of 3 are connected to each other by a rectangular outer peripheral constraining plate 25 serving as an outer frame of the lattice-like structure.
A plurality of grid openings 27 arranged in two rows are defined. The illustrated horizontal support structure 20 eventually defines 204 lattice openings 27. The lattice openings 27 have rack cells made of a material having the same shape as the conventional one and a large neutron absorption capacity. Is inserted.

The horizontal support structure 20 is an alternative to the conventional support plate 5 (see FIGS. 9 and 10). In order to stably support a long rack cell, the horizontal support structure 20 is similarly spaced in the vertical direction. Vertical pillar members (not shown).
Are connected by. Further, three height adjusting mechanisms, that is, level adjusting devices 30 are arranged outside the outer peripheral restraint plate 25 of the horizontal support structure 20. Each level adjusting device 30 is located in the vicinity of the corner of the outer peripheral restraint plate 23. However, when four horizontal support structures 20 are horizontally arranged like a conventional support plate, the lower right corner in the figure. Is centrally located and inaccessible from the outside, another leveling device 40 is provided directly below the corner grid opening 27. The detailed structure of the level adjusting device 30 is shown in FIGS. 4 and 5. 4 and 5, the opening box 33 is fixed to the upper surface of the seat plate 31 which is mounted on the bottom surface of the storage pool. The level adjusting bolt 35 in which the disc-shaped foot portion is fitted inside the box 33 has a threaded surface on the outer surface of the shaft portion, and has a tool fitting rectangular cross-section head portion 35a at the upper end. On the other hand, a support bracket 37 is attached to the lower end of a leg member 36 connected to an outer peripheral restraint plate (not shown), and a nut 38 is fixed to a horizontal plate 37a of the support bracket 37 by welding. The thread surface of the level adjusting bolt 35 described above is screwed into the nut 35, and the rectangular cross-section head portion 35a thereof penetrates the above-mentioned horizontal plate 37a and projects vertically upward. And
A locking nut 39 is screwed onto the thread surface of the level adjusting bolt 35 above the horizontal plate 37a.

In the level adjusting device 30 having the structure as described above, the weight related to the horizontal support structure 20 is the leg member 36,
It is transmitted to the level adjusting bolt 35 via the support bracket 37 and the nut 38, and further transmitted from the disc-shaped foot portion to the bottom of the storage pool via the seat plate 31. To adjust the height, first loosen the locking nut 39, then fit the tool for remote operation to the rectangular cross-section head 35a of the level adjustment bolt 35, and turn it clockwise or counterclockwise to
Adjust the height. When the height is determined, finally, the locking nut 39 is rotated and fixed.

The level adjusting device 40 mounted below the rack cell is constructed as shown in FIG.
The rack cell 51 has a lower end cut off from the normal one, but is common in that it has a fuel stop plate 55 having a cooling water hole 53. A hole 43 is formed in a top plate of the support bracket 41 located immediately below the rack cell 51, and a level adjusting bolt 47 penetrating the lower plate 45 is screwed into a nut 46. The lower end of the level adjusting bolt 47 is in contact with the seat plate 49, and the seat plate 49 rests on the bottom of the storage pool. Since the nut 46 is fixed to the lower plate 45 of the support bracket 41 joined to the horizontal support structure 20, if the nut 46 is extended inside the rack cell and the corner head 47a of the level adjusting bolt 47 is turned by a remote control tool, the support bracket is supported. 41, and thus the height of the horizontal support structure 20 is adjusted.

Next, a structure for fixing the horizontal support structure 20 to the side wall of the storage pool will be described with reference to FIGS. 7 and 8.
The fixed plate 19 fixed to the embedded plate on the side wall of the storage pool and the holder 17 fixed to this have the same structure as the conventional one. Therefore, when the existing equipment is modified to the equipment of the present invention, it can be used and can be left attached to the side wall. The comb-shaped connecting plate 61 is inserted into the internal slots of the holders 17 arranged at intervals, and the inner ends of the wide tooth-shaped portions located between the adjacent holders 17 are slightly aligned with the horizontal support structure 20. Protruding towards. This comb-shaped connecting plate 6
1 has the same outer shape as the portion left on the holder 17 side when the conventional integrally processed support plate 5 is cut in the side wall direction at the portion of the connection hole 11, and the cut remaining portion is used as it is in the above modification. it can. On the other hand, on the outer side of the outer peripheral restraint plate 25 of the horizontal support structure 20, a block connection plate 65 having a plurality of horizontal connection plates 63 protruding toward each of the tooth-like portions of the connection plate 61 is attached. Of course, the horizontal connecting plate 63 may be directly attached to the outer peripheral restraint plate 25. Then, both ends of the flat plate-like connecting plate 67 are fixed to the horizontal connecting plate 63 and the tooth-like portions of the connecting plate 61 by connecting bolts 69 and nuts. The bolt holes and the like of the connection plate 67 may be machined together with the bolt holes of the connecting plate 61 when they are finally attached to the storage pool. In addition,
Since the connection plate 67 is located between the adjacent holders 17, an appropriate width dimension is set to allow relative displacement due to the difference in thermal expansion as described above, or a design such as a long bolt hole is designed. Consideration is given.

In the horizontal support structure 20 having the structure described above, the rack cell receives the rack cell in the lattice opening 27, and the rack cell receives and stores the fuel assembly as the spent fuel. Since the lower ends of the rack cells other than the rack cell 51 are placed on the bottom of the storage pool, the own weight and the weight of the fuel assembly are directly supported by the bottom of the pool, and the horizontal support structure 20 stores the horizontal load generated during an earthquake in the storage pool. Tell the side wall of.

[0013]

As described above, according to the present invention, since the horizontal support structure is constructed by assembling the beam member and the beam member so as to intersect with each other, the rack cell is used for high density storage of the spent fuel. Even if the interval is narrowed, large machining is not required, and it can be manufactured at low cost. Further, according to the present invention, since the height adjusting mechanism having the screw member that can be remotely controlled from above is provided outside the vertical projection plane of the horizontal support structure, the height can be adjusted while the storage pool is filled with water. Can be adjusted. Furthermore, according to the present invention, since the bolt is used for the connecting and fixing portion between the horizontal support structure and the storage pool, the work in water is easy, and the installation and replacement can be easily performed.

[Brief description of drawings]

FIG. 1 is a plan view showing a main part of an embodiment of the present invention.

FIG. 2 is a partial perspective view showing a part of FIG. 1 in an enlarged manner.

FIG. 3 is an exploded perspective view of main members constituting the embodiment.

FIG. 4 is a partial cross-sectional view showing an enlarged part of the embodiment.

FIG. 5 is a partial plan view corresponding to FIG.

FIG. 6 is a partial cross-sectional view showing another portion of the embodiment in an enlarged manner.

FIG. 7 is a partially enlarged plan view showing another main part of the embodiment.

FIG. 8 is an elevational view corresponding to FIG.

FIG. 9 is a partially omitted perspective view showing the overall structure of a conventional facility.

FIG. 10 is a perspective view showing a part of FIG. 9 extracted.

FIG. 11 is a conceptual elevational view showing a part of FIG. 10 in an enlarged manner.

FIG. 12 is a perspective view showing a part of FIG. 10 extracted.

13 is a vertical sectional view corresponding to FIG.

FIG. 14 is an operation explanatory view of the conventional one.

[Explanation of symbols]

1 storage pool 17 Holder 19 Fixed plate 20 Horizontal support structure 21 Upper strip 21a slot 23 Lower strip 23a slot 25 Peripheral restraint plate 27 lattice opening 30 level adjuster 31 seat plate 33 opening box 35 Level adjustment bolt 35a rectangular section head 36 leg members 37 Support bracket 38 nuts 39 Lock nut 40 level adjuster 41 Support bracket 43 holes 45 Lower plate 46 nuts 47 Level adjustment bolt 49 seat 51 rack cells 53 Cooling water hole 55 Fuel stop plate 61 Connecting plate 63 Horizontal connection plate 65 block connection plate 67 Connection plate

─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-53-65597 (JP, A) JP-A-8-233983 (JP, A) Actual development Sho-61-206898 (JP, U) Actual public 2- 16319 (JP, Y2) (58) Fields investigated (Int.Cl. ⁷ , DB name) G21C 19/07

Claims (2)

(57) [Claims] 1. A horizontal support structure that defines a plurality of insertion holes arranged in a grid opening in a storage pool filled with water, and a fuel assembly that is individually inserted into each of the insertion holes. And a long beam in which the horizontal support structure is formed with a plurality of notches arranged side by side in the spent fuel cooling and storage facility. combinations intersect the members together are configured by connecting to each other by the outer peripheral constraining plate both ends of the long Shakuketa member and Nagashakuhari member, fixed to the horizontal support structure on a bottom surface of the storage pool Do
A height adjustment mechanism is provided outside the vertical projection plane of the horizontal support structure.
The height adjustment mechanism can be operated from above vertically.
A supporting device for a spent fuel cooling and storage facility, which is characterized by having the same member . 2. A container arranged in a storage pool filled with water.
Horizontal support that defines a plurality of insertion holes arranged in a child opening
Fuel is inserted into each of the structure and the insertion hole individually.
With a rectangular tubular rack cell that receives and houses the aggregate
In the spent fuel cooling storage facility, the horizontal support structure
The structure has a plurality of cutouts formed on one side surface.
Long beam members and long beam members intersect and combine with each other
The both ends of the long girder member and the long beam member to the outer peripheral restraint plate.
Are connected to each other by means of a space between the horizontally extending embedded plates on the side wall of the storage pool.
Integrated processing type support inserted into a rectangular cross-section holder attached to a plurality of horizontal fixing plates that are protrudingly arranged
Comb, which is the uncut portion obtained by cutting the plate in the side wall direction at the connection hole
To Jo connecting plate, the horizontal support structure supporting device of the spent fuel cooling storage facility, characterized in that the horizontal connecting plate is bolted through the connection plate projecting from the outer periphery constraint plate.