JP6155048B2 - New fuel storage facility - Google Patents

Description

  The present invention relates to a new fuel storage facility for storing unused new fuel installed in a nuclear reactor.

  Examples of nuclear reactors used in nuclear power plants include pressurized water reactors and boiling reactors. In this nuclear reactor, a large number of fuel assemblies (fuels) are arranged inside, and light water is used as a reactor coolant and a neutron moderator, and the light water is heated by the heat generated by the nuclear fission of the fuel. Electricity is generated by heated light water (steam).

  In such a nuclear reactor, a storage pit for temporarily storing an unused fuel assembly (hereinafter referred to as new fuel) to be newly used is provided in the reactor building. The storage pit is provided with a new fuel storage rack that supports the new fuel in an upright state.

  Conventionally, for example, in a new fuel storage facility (nuclear fuel assembly storage facility) described in Patent Document 1, new fuel is applied to the floor of a storage pit (storage) that is surrounded by a side wall and opened at the top. A plurality of cylindrical storage cells (rack) to be stored are stand and fixed. The storage pit is provided with a plate-shaped walkway above the storage cell and covering the entire open portion. The corridor is formed with an opening penetrating at a position directly above each storage cell fixed to the storage pit. The opening is provided so as to be opened and closed by a transparent lid. The walkway is constructed ruggedly as a means of approaching the worker's storage cell. The lid is transparent, so that the new fuel stored in the storage cell can be inspected (confirmation of whereabouts) with the opening closed, and the opening can be opened to the storage cell. New fuel can be taken in and out.

Japanese Utility Model Publication No.59-1000029

  In the new fuel storage facility described in Patent Document 1 described above, a walkway is provided so as to cover the entire open portion of the storage pit, and an operator rides on it, approaches each opening, Inspection and new fuel in / out of storage cell. For this reason, the walkway must be formed to a thickness that is itself strong and reinforced so that it can be installed in the open part of the storage pit above the storage cell. As a result, the new fuel storage facility described in Patent Document 1 has a large amount of corridors, and it takes time to carry in and install the corridors during construction, and requires extensive inspection to ensure strength. Costs and maintenance costs increase.

  The present invention solves the above-described problems, and a means for approaching the storage cell when checking the new fuel stored in the storage pit and when the new fuel is taken in and out of the storage cell, while suppressing manufacturing costs and maintenance costs. The object is to provide a new fuel storage facility that can be obtained.

  In order to achieve the above-mentioned object, the storage facility for new fuel according to the first aspect of the present invention is formed into a storage pit that is surrounded by a vertical wall surface around the floor surface and has a cylindrical shape with an upper end opened. A plurality of storage cells arranged on the floor of the storage pit so that new fuel can be taken in and out from the opening at the upper end, and a part of the storage pit is provided across the edge of the opening of the storage pit. And a portable walkway over the storage cell.

  According to the storage facility for new fuel, it is possible to put the new fuel into and out of the storage cell or to check the location of the new fuel stored in the storage cell (confirmation of whereabouts). The walking corridor used as the approaching means is provided so as to straddle a part between the edges of the opening part of the storage pit, and is spanned above a part of the storage cells. Since the walkway is portable, it can be applied as a means of accessing all new fuel stored in the storage pit. For this reason, the amount of the corridor is reduced as compared with the conventional one, the labor for carrying in and installing the corridor during construction of the new fuel storage facility is reduced, and the inspection for ensuring the strength does not become large. As a result, it is possible to obtain a means for approaching the storage cell at the time of inspection of new fuel stored in the storage pit and loading / unloading of new fuel to / from the storage cell, while suppressing manufacturing costs and maintenance costs.

  The storage facility for new fuel according to the second invention is the lid according to the first invention, wherein the opening of the storage cell can be opened and closed, and at least a part corresponding to the opening of the storage cell is formed of a transparent material. The walkway has a window at a position corresponding to the lid of the storage cell immediately below the walkway.

  According to this new fuel storage facility, it is possible to easily check the new fuel stored in the storage pit from above the walkway.

  The storage facility for new fuel according to a third aspect is characterized in that, in the second aspect, the window is covered with a transparent material.

  According to this new fuel storage facility, safety can be ensured without an operator stepping on the opening of the window when an operator walks along the walkway.

  The storage facility for new fuel according to a fourth aspect of the present invention is the storage device for a new fuel according to any one of the first to third aspects, wherein the storage pit is formed with an open portion opened in a rectangular shape. In the storage pit, the storage pit is provided so as to straddle between the edges on the near side.

  According to this new fuel storage facility, by reducing the length (size) of the corridor as much as possible, the amount of the corridor is reduced, and the means of approaching the storage cell can be further reduced in manufacturing and maintenance costs. Can be obtained.

  Moreover, the storage facility for a new fuel according to a fifth aspect of the present invention is the first to fourth aspects of the invention, wherein the walkway has a suspension piece.

  According to this new fuel storage facility, it can be realized by applying a suspension piece that suspends the corridor with an overhead crane or the like as a specific means configured to be portable.

  The storage facility for new fuel according to a sixth aspect of the present invention is characterized in that, in any one of the first to fifth aspects, the corridor has a wheel that rolls an edge of an open portion in the storage pit. To do.

  According to this new fuel storage facility, it can be realized by applying a wheel that slides the corridor along the edge of the opening in the storage pit as a specific means configured to be portable.

  According to a seventh aspect of the present invention, there is provided a new fuel storage facility according to any one of the first to sixth aspects, wherein the plurality of storage cells are supported by a fuel storage rack and spacers are provided on an outer peripheral portion of the fuel storage rack. The fuel storage rack is placed without being fixed to the floor surface of the storage pit.

  According to this new fuel storage facility, the storage cell is not fixed to the floor surface of the storage pit, the fuel storage rack is placed on the floor surface of the storage pit, and the vertical wall surface of the storage pit or the adjacent fuel storage space by the spacer. Keep the distance from the rack. For this reason, since the foundation bolt etc. which fix a storage cell to the floor surface of a storage pit are not used, the cost concerning manufacture and attachment of a foundation bolt can be omitted.

  According to the present invention, it is possible to obtain means for approaching the storage cell when checking the new fuel stored in the storage pit and when the new fuel is taken in and out of the storage cell, while suppressing the manufacturing cost and the maintenance cost.

FIG. 1 is a side sectional view showing a new fuel storage facility according to an embodiment of the present invention. FIG. 2 is a plan view showing the storage facility for new fuel according to the embodiment of the present invention. FIG. 3 is a perspective view showing a fuel storage rack in the new fuel storage facility according to the embodiment of the present invention. FIG. 4 is a partially enlarged longitudinal sectional view of the new fuel storage facility according to the embodiment of the present invention. FIG. 5 is a partially enlarged plan view of the storage facility for new fuel according to the embodiment of the present invention. FIG. 6 is a partially enlarged longitudinal sectional view of the new fuel storage facility according to the embodiment of the present invention. FIG. 7 is a plan view showing another example of the new fuel storage facility according to the embodiment of the present invention. FIG. 8 is a schematic configuration diagram showing a nuclear power plant. FIG. 9 is a schematic view showing a reactor containment vessel.

  Embodiments according to the present invention will be described below in detail with reference to the drawings. In addition, this invention is not limited by this embodiment. In addition, constituent elements in the following embodiments include those that can be easily replaced by those skilled in the art or those that are substantially the same.

  The storage facility for new fuel of this embodiment is applied in a nuclear power plant. FIG. 8 is a schematic configuration diagram showing a nuclear power plant, and FIG. 9 is a schematic diagram showing a nuclear reactor containment vessel.

  In the present embodiment, for example, as shown in FIG. 8, a pressurized water reactor (PWR: Pressurized Water Reactor) 112 is applied to the nuclear power plant. The pressurized water reactor 112 uses light water as a reactor coolant and a neutron moderator to produce high-temperature and high-pressure water that does not boil over the entire primary system, and sends this high-temperature and high-pressure water to the steam generator 113 to generate steam by heat exchange. The steam is sent to the turbine 118 to generate electricity with the generator 123.

  In a nuclear power plant having this pressurized water reactor 112, a pressurized water reactor 112 and a steam generator 113 are stored inside a reactor containment vessel 111. The pressurized water reactor 112 and the steam generator 113 are connected via cooling water pipes 114 and 115. The cooling water pipe 114 is provided with a pressurizer 116, and the cooling water pipe 115 is provided with a cooling water pump 117. In this case, light water is used as the moderator and the primary cooling water, and the primary cooling system is controlled by the pressurizer 116 so as to maintain a high pressure state of about 160 atm in order to suppress boiling of the primary cooling water in the core. Yes. Therefore, in the pressurized water reactor 112, the light water as the primary cooling water is heated by the low-enriched uranium or MOX as the fuel, and the cooling water pipe is maintained while the high temperature primary cooling water is maintained at a predetermined high pressure by the pressurizer 116. 114 is sent to the steam generator 113. In the steam generator 113, heat exchange is performed between the high-pressure and high-temperature primary cooling water and the secondary cooling water, and the cooled primary cooling water is returned to the pressurized water reactor 112 through the cooling water pipe 115.

  The steam generator 113 is connected to a turbine 118 and a condenser 119 provided outside the reactor containment vessel 111 via cooling water pipes 120 and 121, and a water supply pump 122 is provided in the cooling water pipe 121. ing. The turbine 118 is connected to a generator 123, and the condenser 119 is connected to a water intake pipe 124 and a drain pipe 125 for supplying and discharging cooling water (for example, seawater). Therefore, the steam generated by performing heat exchange with the high-pressure and high-temperature primary cooling water in the steam generator 113 is sent to the turbine 118 through the cooling water pipe 120, and the turbine 118 is driven by this steam to generate the generator 123. To generate electricity. The steam that has driven the turbine 118 is cooled by the condenser 119 and returned to water, and then returned to the steam generator 113 through the cooling water pipe 121.

  In the nuclear power plant configured as described above, the reactor containment vessel 111 contains therein the above-described pressurized water reactor 112, steam generator 113, pressurizer 116, and the like, as shown in FIG. Yes. Further, a fuel handling building 130 is installed adjacent to the reactor containment vessel 111, and the new fuel storage facility 1 is provided in the fuel handling building 130. The fuel handling building 130 has an overhead crane 131 installed on the ceiling.

  The storage facility for new fuel 1 is made of concrete, and has a storage pit 2 surrounded by a vertical wall surface 2b around a floor surface 2a and opened upward. The storage pit 2 has a fuel storage rack 3 installed therein. The fuel storage rack 3 stores new fuel that is an unused fuel assembly installed in the nuclear reactor. Although the fuel assembly is not explicitly shown in the drawing, in the case of PWR, a plurality of fuel rods are configured to be bundled in a rectangular shape by a support grid, and the upper nozzle is fixed to the upper end portion, while the lower end The lower nozzle is fixed to the part. In addition, when the fuel assembly is for a boiling water reactor (BWR), a plurality of fuel rods are bundled in a rectangular shape by a spacer grid, and the upper tie plate is fixed to the upper end portion, A lower tie plate is fixed to the lower end portion, and a nose piece protrudes and is fixed to the lower side of the lower tie plate.

  1 to 7 show a new fuel storage facility according to this embodiment. As shown in FIGS. 1 and 2, the storage pit 2 is formed as a concave portion in which a vertical wall surface 2 b is erected vertically on four sides of a rectangular floor surface 2 a in a plan view and an upper portion is opened. The storage pit 2 is provided with an operation floor 2c outside the recess. In addition, the storage pit 2 is formed with a weir 2d protruding from the operation floor 2c so as to surround the periphery of the open portion. The storage pit 2 shown in FIGS. 1 to 7 is formed in a rectangular shape in plan view (the floor surface 2a and the open portion), and the storage pit 2 shown in FIGS. 1 to 6 is the storage shown in FIG. Compared with the pit 2, it is formed in a slender shape. Such a storage pit 2 has a fuel storage rack 3 installed therein.

  As shown in FIGS. 1 to 3, the fuel storage rack 3 includes an upper support portion 3 </ b> A, an intermediate support portion 3 </ b> B, and a platform 3 </ b> C. As shown in FIG. 3, the upper support portion 3A includes a support grid 3Aa assembled in a lattice shape and a rectangular outer frame 3Ab surrounding the support grid 3Aa. The upper support portion 3A includes the support grid 3Aa and the outer frame 3Ab. A lattice forming a new fuel storage area is formed. The intermediate support portion 3B is configured in the same manner as the upper support portion 3A. The intermediate support portion 3B includes a support lattice 3Ba assembled in a lattice shape and a rectangular outer frame 3Bb surrounding the support lattice 3Ba. The outer frame 3Bb forms a lattice that forms a new fuel storage area. The platform 3 </ b> C serves as a base for the fuel storage rack 3, and is placed on the floor 2 a of the storage pit 2 without being fixed. The upper support portion 3A, the intermediate support portion 3B, and the base plate 3C are connected by a connecting member 3D with a predetermined interval from the top in the order of the upper support portion 3A, the intermediate support portion 3B, and the base plate 3C. The connecting member 3D is disposed so as to intersect at an outer peripheral portion between the upper support portion 3A and the intermediate support portion 3B and an outer peripheral portion between the intermediate support portion 3B and the base plate 3C. In the fuel storage rack 3, spacers 3E are provided on the outer periphery of the outer frame 3Ab of the upper support 3A, the outer periphery of the outer frame 3Bb of the intermediate support 3B, and the outer periphery of the base 3C. As shown in FIGS. 1 and 2, the spacer 3E abuts the vertical wall surface 2b of the storage pit 2 and the spacer 3E of the adjacent fuel storage rack 3 to thereby contact the vertical wall surface 2b of the storage pit 2 and the adjacent fuel. The distance from the storage rack 3 is maintained.

  The fuel storage rack 3 is provided with a storage cell 4. The storage cell 4 is formed of a rectangular cylinder whose upper portion is opened by a square steel pipe, and is inserted and stored with new fuel. The storage cell 4 is inserted into the storage area of the upper support portion 3A and the storage area of the intermediate support portion 3B, and the lower end portion is supported by the platform 3C. In the fuel storage rack 3, the lattice formed by the support lattices 3Aa and 3Ba of the upper support portion 3A and the intermediate support portion 3B is configured to hold adjacent storage cells 4 at a predetermined interval. That is, the storage cells 4 in one fuel storage rack 3 are arranged so as to keep the new fuel stored adjacent thereto at a predetermined interval. For this reason, adjacent new fuels can be prevented from reaching criticality. Adjacent fuel storage racks 3 are arranged so as to keep the fuel storage racks 3 at predetermined intervals by spacers 3E. For this reason, it is possible to prevent the adjacent new fuels from reaching criticality in the adjacent fuel storage racks 3.

  The storage cell 4 is formed with a guide portion 4A whose upper end extends obliquely outward and upward. The guide 4A guides the insertion of new fuel stored in the cylinder. In addition, the storage cell 4 has a stopper plate 4 </ b> B that closes the inside of the cylinder in a lower end portion thereof. The stop plate 4B supports the lower end of the new fuel inserted into the cylinder. The stop plate 4B is provided at a position raised from the cylindrical lower end of the storage cell 4, and a through hole 4Ba penetrating vertically is formed. The through hole 4Ba drops a nose piece when a new BWR fuel is stored, or drops dust when it enters the cylinder. Further, the storage cell 4 extends from the lower end to a portion that hangs on the stop plate 4B, and is formed with a cutout 4C that penetrates into and out of the cylinder. If dust or water enters the cylinder, it is taken out of the cylinder from the stop plate 4B and the notch 4C so that the dust and water do not stay in the cylinder.

  Further, as shown in FIGS. 4 and 5, the storage cell 4 has a lid 4D attached to the upper end portion. The lid 4 </ b> D opens and closes the opening at the upper end of the storage cell 4, and closes the opening at the upper end of the storage cell 4 when attached to the upper end of the storage cell 4. Prevent entry of foreign matter such as dust. On the other hand, when the lid 4 </ b> D is removed from the upper end of the storage cell 4, the opening of the upper end of the storage cell 4 is opened, whereby new fuel is taken in and out of the storage cell 4. The lid 4 </ b> D includes a covering portion 4 </ b> Da that covers the opening of the storage cell 4 and an outer frame portion 4 </ b> Db that surrounds the upper end portion of the storage cell 4. The covering portion 4Da is entirely or at least partially formed of a transparent material made of a synthetic resin such as tempered glass or polycarbonate resin. The lid 4D has a handle portion 4Dc. The handle portion 4Dc is for gripping when the lid 4D is attached to or detached from the upper end portion of the storage cell 4. The handle portion 4Dc protrudes above the lid 4D, and is fixed to the upper surface of the covering portion 4Da in this embodiment. The lid 4D can be opened and closed by, for example, a rod-shaped tool having a J-shaped hook attached to the lower end.

  In a state where the fuel storage rack 3 is disposed in the storage pit 2, the storage cell 4 is stored in the storage pit 2 as shown in FIG. 1, and the upper end of the storage cell 4 is below the opening of the storage pit 2. To position.

  In the present embodiment, the new fuel storage facility 1 shown in FIGS. 1 to 6 is a fuel storage rack 3 in which 12 storage cells 4 are arranged in a total of 12 × 3 × 4. 5 shows a configuration in which five storage cells 4 are arranged in the storage pit 2 as a whole by arranging five in the elongate direction. Further, in the new fuel storage facility 1 shown in FIG. 7, the fuel storage rack 3 has 60 storage cells 4 in total of 6 × 10, and a total of 60 storage cells 4 are disposed in the storage pit 2. Shows the form. The shape of the storage pit 2 in plan view, the number of storage cells 4 in the fuel storage rack 3, and the layout of the fuel storage rack 3 are not limited to the above forms.

  The new fuel storage facility 1 of this embodiment has a corridor 5. The corridor 5 has a corridor main body 5A serving as a bridge provided across a part between the edges of the opening portion of the storage pit 2. The walkway main body 5A is preferably made of a steel such as carbon steel or stainless steel, or a non-ferrous metal such as an aluminum alloy in order to reduce the weight. The corridor body 5A is formed to have a length longer than the distance between the opposing edges of the opening portion of the storage pit 2, and is operated so that both ends in the longitudinal direction are hooked on the opposing weir 2d formed at the edge of the opening portion of the storage pit 2. It is placed on the floor 2c and is bridged above some of the storage cells 4 described above. Specifically, the walkway main body 5A is provided across the edges on the side closer to the distance in the storage pit 2 formed by opening the opening portion in a rectangular shape. That is, in the state where the walkway main body 5A is bridged above the storage cell 4, a part (six in the present embodiment) of the storage cells 4 exists immediately below, and the upper part of the other storage cells 4 is open. It is assumed that it was made form.

  In the corridor 5, side pillars 5B are set up at both width ends of the corridor main body 5A at intervals along the longitudinal direction. The side pillars 5B arranged at each width end of the corridor body 5A are connected by a handrail 5C. The handrail 5C is formed of a steel bar, a wire, a rope, or the like. The side pillar 5B can be removed from the walkway body 5A, and the handrail 5C can be removed from the side pillar 5B, and the portability can be improved in the walkway 5 configured to be portable as described later. It is illustrated.

  Further, the walkway 5 is provided with a pair of suspension pieces 5D at both width ends of the walkway body 5A. The suspension piece 5D is suspended by the overhead crane 131 of the fuel handling building 130 described above. Thereby, the corridor 5 is comprised as a portable type. Further, the walkway 5 is provided with non-slip pads 5E made of a rubber material or the like on the bottom surfaces at both ends in the longitudinal direction of the walkway body 5A placed on the operation floor 2c, and maintains the position spanned above the storage cell 4. Configured to be able to.

  Further, the corridor 5 has a window portion 5F at the position of the corridor main body 5A corresponding to the storage cell 4 directly below (the lid 4D of the storage cell 4) in a state where the walkway main body 5A is bridged above the storage cell 4. Is provided. The window 5F may be formed as a through hole, but is preferably covered with a transparent material made of a synthetic resin such as tempered glass or polycarbonate resin so as to close the through hole.

  As shown in FIG. 6, the corridor 5 may be provided with wheels 5G instead of the non-slip pads 5E on the bottom surfaces at both ends in the longitudinal direction of the corridor body 5A placed on the operation floor 2c. The wheel 5G rolls on the edge (operation floor 2c) of the open part in the storage pit 2. Thereby, the walkway 5 is comprised as a portable type which slide-moves in the state overlaid above the storage cell 4. FIG. Further, the walkway 5 is configured such that a stopper (not shown) is provided on the wheel 5G itself or the walkway body 5A, and the position slid and moved by this stopper can be maintained.

  In the new fuel storage facility 1 configured as described above, the corridor 5 is used to put new fuel into and out of the storage cell 4 or to check the new fuel stored in the storage cell 4 (confirmation of whereabouts). Therefore, it is used as an approach means for the worker to walk to the storage cell 4 to approach. When the new fuel is taken in and out of the storage cell 4, the overhead crane 131 is used from the walkway 5 or the operator himself removes the cover 4 </ b> D of the storage cell 4, and the new fuel is taken in and out by the overhead crane 131. When checking the new fuel, the new fuel is checked through the transparent material in the lid 4D of the storage cell 4.

  The storage facility 1 for new fuel according to the present embodiment is formed in a storage pit 2 that is surrounded by a vertical wall surface 2b around a floor surface 2a and opened at the top, and a cylindrical shape that opens at the top. A storage cell 4 in which a plurality of new fuels are taken in and out from the opening at the upper end in a state of being arranged in plural on the floor surface 2a of 2 and a part of storage provided across a part between the edges of the opening part of the storage pit 2 And a portable corridor 5 that is bridged above the cell 4.

  According to the new fuel storage facility 1, in order to put new fuel into and out of the storage cell 4 or to check the new fuel stored in the storage cell 4 (confirmation of presence / absence), The walkway 5 used as a means for approaching the storage cells 4 is provided so as to straddle a part between the edges of the opening portion of the storage pit 2 and span over a part of the storage cells 4. Since the corridor 5 is portable, it can be applied as a means of approaching all new fuel stored in the storage pit 2. For this reason, compared with the past, the quantity of the corridor 5 is reduced, the labor of carrying in and installing the corridor 5 during construction of the new fuel storage facility 1 is reduced, and the inspection for ensuring the strength may be large. Absent. As a result, it is possible to obtain means for approaching the storage cell 4 at the time of inspection of new fuel stored in the storage pit 2 and introduction / removal of new fuel to / from the storage cell 4 while suppressing manufacturing costs and maintenance costs.

  Further, the new fuel storage facility 1 according to the present embodiment has a lid 4D that can open and close the opening of the storage cell 4 and at least a part of the opening corresponding to the opening of the storage cell 4 is made of a transparent material. The corridor 5 has a window portion 5F at a position corresponding to the lid 4D of the storage cell 4 immediately below.

  According to the new fuel storage facility 1, it is possible to easily check the new fuel stored in the storage pit 2 from above the walkway 5.

  In the new fuel storage facility 1 according to the present embodiment, the window 5F is covered with a transparent material.

  According to the new fuel storage facility 1, when an operator walks along the corridor 5, the safety is ensured without being taken by the opening of the window portion 5 </ b> F.

  Further, in the new fuel storage facility 1 according to the present embodiment, the storage pit 2 is formed so that the open portion is opened in a rectangular shape, and the walkway 5 is located between the edges of the storage pit 2 on the near side. It is provided across.

  According to this new fuel storage facility 1, by reducing the length (size) of the corridor 5 as much as possible, the quantity of the corridor 5 is reduced, and the means for approaching the storage cell 4 can be manufactured and maintained. Can be obtained with more control.

  Moreover, in the new fuel storage facility 1 according to the present embodiment, the corridor 5 has a suspension piece 5D.

  This new fuel storage facility 1 can be realized by applying the suspension piece 5 </ b> D that suspends the corridor 5 using the overhead crane 131 or the like as a specific means configured to be portable.

  In the new fuel storage facility 1 according to the present embodiment, the corridor 5 has wheels 5G that roll on the edge of the open portion of the storage pit 2.

  According to the new fuel storage facility 1, it can be realized by applying the wheel 5 </ b> G that slides the corridor 5 along the edge of the opening in the storage pit 2 as a specific means configured to be portable. .

  Further, in the new fuel storage facility 1 according to the present embodiment, a plurality of storage cells 4 are supported by the fuel storage rack 3 and spacers 3E are arranged on the outer periphery of the fuel storage rack 3 to store the fuel storage rack 3. It is placed on the floor 2a of the pit 2 without being fixed.

  According to this new fuel storage facility 1, the storage cell 4 is not fixed to the floor surface 2a of the storage pit 2, the fuel storage rack 3 is placed on the floor surface 2a of the storage pit 2, and the storage pit 2 is provided by the spacer 3E. The space between the vertical wall surface 2b and the adjacent fuel storage rack 3 is maintained. For this reason, since the foundation bolt etc. which fix the storage cell 4 to the floor surface 2a of the storage pit 2 are not used, the cost concerning manufacture and attachment of a foundation bolt can be saved.

DESCRIPTION OF SYMBOLS 1 Storage facility for new fuel 2 Storage pit 2a Floor surface 2b Vertical wall surface 3 Fuel storage rack 3E Spacer 4 Storage cell 4D Lid 5 Walkway 5A Walkway body 5B Side pillar 5C Handrail 5D Hanging piece 5E Nonslip pad 5F Window part 5G Wheel

Claims (7)

A storage pit that is surrounded by a vertical wall around the floor and the upper part is open,
A storage cell that is formed in a cylindrical shape with an upper end opened and in which a plurality of fuels are placed on the floor of the storage pit and new fuel is taken in and out from the upper end opening;
A portable walkway provided across a portion of the edge of the opening of the storage pit and spanned above some of the storage cells;
Have a, the opening of the housing cell is openably has a lid corresponding to the opening of the housing cell, the corridor has a window portion at a position corresponding to the lid of the storage cells just below the new fuel storage facility characterized in that it comprises a. 2. The storage facility for new fuel according to claim 1, wherein at least a part of the lid corresponding to the opening of the storage cell is made of a transparent material. New fuel storage facility according to claim 1 or 2, characterized in that the window is covered with a transparent material.   The storage pit is formed by opening an opening portion in a rectangular shape, and the walkway is provided across the edges on the near side of the storage pit. The storage facility for new fuel according to any one of the above.   The said walkway has a suspension piece, The storage facility for new fuels as described in any one of Claims 1-4 characterized by the above-mentioned.   The said walkway has a wheel which rolls the edge of the open part in the said storage pit, The storage facility for new fuels as described in any one of Claims 1-5 characterized by the above-mentioned. The plurality of storage cells are supported by a fuel storage rack, a spacer is disposed on the outer periphery of the fuel storage rack, and the fuel storage rack is mounted without being fixed to the floor surface of the storage pit. Item 7. The storage facility for new fuel according to any one of Items 1 to 6.

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