JPS6151279B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a blade guide used when inserting control rods and fuel assemblies into a reactor core.

The fuel assemblies used in boiling water reactors are a set of four fuel assemblies that constitute one cell and are loaded into the core lattice. Control rods must be inserted into the grid. Conventionally, a blade guide is used to insert the control rods and fuel assemblies into the core lattice, and this blade guide has the configuration shown in FIGS. 1 and 2. That is, the blade guide includes a pair of elongated guide bodies 1 and 2. A block-shaped support base 3, 4 is provided at the upper end of each guide body 1, 2.
are provided, and these support bases 3 and 4 are connected to each other by a connecting member 5. This connecting member 5 connects the guide bodies 1 and 2 so that when the guide bodies 1 and 2 are inserted into the core lattice A, the guide bodies 1 and 2 are inserted into mutually opposing inner corners of the core lattice A. Further, the connecting member 5 is provided with a handle 6 for hanging, and the side surfaces of the support bases 3 and 4 are provided with channel fasteners for maintaining the mutual spacing, which are installed on the side surfaces of the upper ends of the fuel assemblies. Also provided are a channel fastener imitation projection 7 and a channel spacer imitation projection 8 which are brought into contact with the channel spacer. In order to insert the control rods and fuel assemblies into the core lattice A using the blade guide having such a configuration, first insert the blade guide into the core lattice A as shown in FIG. The control rod B, which has a cross-shaped cross section as shown by the imaginary line, is inserted from below into the guide body 1,
Insert 2 as a guide. After this, the guide bodies 1 and 2 are guided from above to the fuel assemblies C and C shown by imaginary lines in the spaces S and S formed on the side surfaces of the guide bodies 1 and 2 in the core lattice A, respectively. It is inserted as . However, in the case of a blade guide connected by the connecting member 5 and provided with a handle 6 on the connecting member 5, since the connecting member 5 and the handle 6 are located at the center of the core lattice A. When the fuel assembly C is inserted into the space S, the channel fastener of the fuel assembly C may come into contact with the connecting member 5 and the handle 6. Therefore, due to this contact, it is not possible to easily insert the fuel assembly C, and furthermore, since this insertion work is performed remotely under water, the workability becomes even worse, and the worker is exposed to radiation. There was a problem in that not only the amount of radiation exposure increased, but also the channel fasteners were damaged due to the contact.

This invention was made based on the above-mentioned circumstances, and its purpose is to prevent damage to the channel fasteners of a fuel assembly during insertion, and to facilitate the insertion work to reduce radiation exposure of workers. An object of the present invention is to provide a blade guide that can reduce the amount of blade guide.

An embodiment of the present invention will be described below with reference to FIGS. 3 to 6.
This will be explained based on the diagram.

In the figure, reference numerals 11 and 12 are a pair of cylindrical guide bodies, for example. These guide bodies 11, 12
have the same length as the fuel assembly, and have an outer diameter such that they can be inserted diagonally into each other within the core lattice A. Box-shaped support bases 13 and 14 are provided at the upper ends of each guide body 11 and 12, and these support bases 13 and 14 are connected to each other by a connection frame 15. That is, the connecting frame 15 is square, and the supporting bases 13 and 14 are fixed to the inner corners facing each other. Furthermore, as shown in FIGS. 2 and 3, the connecting frame 15 has a size that allows it to catch on the upper surface of the core lattice A when the guide bodies 11 and 12 are inserted into the core lattice A. There is. A top plate 14a is provided on the upper side of one of the support bases 14.
A handle 16 for hanging is attached to 4a, avoiding the center position of the connection frame 15. Further, the side surfaces of each of the support bases 13 and 14 are in contact with channel fasteners D and channel spacers E for maintaining mutual spacing, which are provided on the side surfaces of the upper end of the fuel assembly C shown in FIG. A channel fastener imitation projection 17 and a channel spacer imitation projection 18 are provided. Tapered lower tie plates 19 and 20 are attached to the lower ends of the guide bodies 11 and 12 to fit into the fuel support fittings (not shown) of the core. Further, a weight 21 is provided inside the guide body 12 to which the handle 16 is attached, and the weight 21 allows the center of gravity to be located below the handle 16.

During refueling, the blade guide configured as described above is transported by gripping the handle 16 with the grip of the refueling machine, and is inserted into the core grid A from above as shown in FIG. 4. After inserting the control rod B, which has a cross-shaped cross section, into the core lattice A from below using the guide bodies 11 and 12 as guides, the control rod B formed by the side surfaces of the guide bodies 11 and 12 and the connecting frame 15 is inserted. space, s, 6th in s
Insert the fuel assembly C shown in the figure from above.
At this time, the guide bodies 11 and 12 serve as guides, allowing the fuel assembly C to be inserted smoothly.

According to the blade guide having such a configuration, the guide bodies 11 and 12 are connected to each other by the square connecting frame 15, and the handle 16 is attached to the upper surface of one of the support bases 14 at the center of the connecting frame 15. Since the fuel assembly C is attached so as to avoid the position, when the fuel assembly C is inserted into the space S, the channel fastener D of the fuel assembly C does not come into contact with the handle 16 or the connecting frame 15. There is no. Therefore, the work of inserting the fuel assembly C becomes easier, the time required for this work can be shortened, and the amount of radiation exposure of the worker can be reduced. Furthermore, since the channel fastener D does not come into contact with the handle 16 or the connecting frame 15, damage to the channel fastener D due to this contact can be prevented, and safe work inside the reactor core can be ensured. It is. In addition, in this embodiment, when the blade guide is transferred by gripping the handle 16, since a weight 21 is provided inside the guide body 12 on the side to which the handle 16 is attached, the guide body 11, The balance of 12 is adjusted, and these guide bodies 11 and 12 can be held and transported in the vertical direction. Therefore, insertion of the blade guide into the core lattice A becomes easy. Moreover, since such an effect can be obtained simply by providing the weight 21, manufacturing of the blade guide can be simplified.

Note that the present invention is not limited to the above embodiment.

For example, the guide body is not limited to a cylindrical shape.
It may also be in the shape of a square column like the fuel assembly. Further, if handles are provided on the upper surface of each support base and these handles are simultaneously gripped by the gripping tool of the fuel exchanger, the above-mentioned weight becomes unnecessary.

As explained above, the present invention fixes the upper end of the guide body to the mutually opposing inner corners of the square connecting frame, and also attaches the handle for hanging to the upper surface of the connecting frame or the guide body. It is attached in a position that avoids the center of the body. Therefore, during fuel exchange, when inserting the fuel assembly into the core lattice using the blade guide with the above configuration as a guide, the channel fasteners of the fuel assembly do not come into contact with the handle or the connecting frame. do not have. Therefore, the workability in inserting the fuel assembly is improved, the amount of radiation exposure of the worker can be reduced, and damage to the channel fastener due to the contact can be prevented, which has great effects.

[Brief explanation of the drawing]

1 and 2 show a conventional example, with FIG. 1 being a perspective view of the blade guide, and FIG. 2 being a plan view of the blade guide inserted into the core lattice. 3 to 6 show an embodiment of the present invention, FIG. 3 is a perspective view of the blade guide, FIG. 4 is a plan view of the blade guide inserted into the core lattice, and FIG. 5 is a perspective view of the blade guide. Side view of the blade guide inserted into the core lattice,
FIG. 6 is a perspective view showing the insertion of a fuel assembly into the core lattice. 11, 12... Guide main body, 15... Connection frame body, 16... Handle, 21... Weight.

Claims (1)

[Claims] 1. A rectangular connecting frame, a pair of elongated guide bodies whose upper ends are fixed to mutually opposing inner corners of the connecting frame, and the connecting frame or the guide body. A blade guide characterized by comprising a handle for hanging attached to the upper surface at a position avoiding the center of the connecting frame. 2. A patent claim characterized in that the above-mentioned handle is attached to the upper surface of one of the above-mentioned guide bodies, and a weight for balance adjustment is provided within the guide body to position the center of gravity below the above-mentioned handle. The blade guide according to item 1 of the scope.