JPS6055295A - Storage rack of control rod - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] This invention relates to a storage rack for spent control rods that is placed in a fuel storage pool within a nuclear reactor building.

[Technical background of the invention]

Figures 1 to 3 show control rod storage racks installed in the fuel storage pool inside the reactor building of a conventional boiling water reactor.
This will be explained using figures.

FIG. 1 shows the fuel storage pool and its surrounding area, and in the figure, 1 is a reactor pressure vessel, and 2 is a reactor containment vessel in which the pressure vessel 1 is stored. Inside the reactor pressure vessel 1, a reactor core 3 including a large number of fuel assemblies and control rods is installed. Further, a reactor well 4 is formed above the reactor pressure vessel 1, and a fuel storage pool 5 is formed on one side of the reactor well 4. The fuel storage pool 5 opens to an operating floor 7 in the reactor building, and rails 9 on which the fuel exchanger 8 runs are laid on the operating floor 7. Fuel exchange machine 8 Nihatsu 75) Tools 1
A hoist 11 is provided to raise and lower the 0.

Inside the fuel storage pool 5, a fuel assembly storage rack 12 and a control rod storage rack 13 are provided. The fuel assemblies and control rods installed in the reactor core 3 are
After a certain period of time, the fuel assemblies are removed from the reactor core 3 and the reactor pressure vessel 1, and the fuel assemblies are transferred to the fuel assembly storage rack 12, and the control rods are transferred to the control rod storage rack 13 and stored. In addition, when taking out the fuel assembly or control rod from the reactor core 3 in this way, the gate 14 is removed using the fuel exchanger 8 and the pool water in the fuel storage pool 5 is allowed to flow into the reactor well 4. A grip 10 having a desired shape is attached to the fuel exchanger 8, and the control rod is lifted through the handle at its upper end, transported through the pool water in the reactor well 4 and the fuel storage boule 5, and stored in the control rod storage rack 13. do.

When transporting the control rod, it is necessary to transport the control rod in water deeper than a certain depth so that radiation shielding can be performed effectively. When holding control rods in the control rod storage rack 13, a structure in which the control rods are inserted from above cannot ensure a constant radiation shielding water depth during transport of the control rods.

Therefore, a structure is generally adopted in which the control rod is held from the side.

Fig. 2 shows a conventional control rod storage rack 3, in which there is one upper hanger 5 protruding from the inner wall of the fuel storage pool 5, each with its free tip slightly inclined upwards, and two parallel lower hangers. The upper hanger 15 suspends the handle 18 of the control rod 17, and the lower support rod 1
6. Coupling socket part 1 at the lower end of the control rod 17 at 16
9 to prevent the control rod 17 from falling due to vibration.

[Problems with background technology]

In the conventional control rod storage rack 13 as described above,
Since the free ends of the upper hanger 15 and the lower support rod 16° 16 are inclined one angle upward, the work of hanging the handle 18 of the control rod 17 from the upper hanger 15 is carried out using the hoist 11 while horizontally moving the fuel exchanger 8. This had to be done by slowly lowering the grip 10 and moving the control rod F diagonally downward laterally as shown by the arrow 20 in FIG. In this case, the control rods 17 and the control rod storage racks 13
Since these are located deep underwater in the fuel storage pool 5 and are difficult to see visually, the operator of the fuel exchanger 8 must perform the above operations while groping remotely, and such operations require advanced equipment. It requires skill, takes a long time, and there is a risk that the radiation exposure of the operator will be high.

[Purpose of the invention]

This invention was made in order to solve the above-mentioned problems of control rod storage racks in conventional fuel storage pools,
It is an object of the present invention to provide a control rod storage rack that is easy to operate to hold control rods, shortens working time, and reduces the total radiation exposure of operators.

[Summary of the invention]

The control rod storage rack according to the present invention has an innermost cylindrical shape with the front and top surfaces open, and allows the control rods to be introduced horizontally from the open front surface, so that the length direction is vertical and the fuel storage rack is opened. The storage rack body is fixed inside the storage rack body, and the bottom part of the storage rack body is biased upward and is installed horizontally so that it can be moved up and down a certain distance, and when a control rod is placed, it is lowered and the control rod is removed. When the movable receiving plate rises and returns, its lower end is fixed to each side edge of the movable receiving plate, and its upper end extends upward and closes in conjunction with the lowering of the movable receiving plate and is housed in the storage rack body. The above-mentioned object is achieved by providing a connecting plate that forms a grip portion that grips and releases the upper part of the control rod.

[Embodiments of the invention]

An embodiment of the present invention will be described with reference to FIGS. 4 to 7.

The two fixing fittings 21.21 having a rectangular cross section are suspended from the protruding portion of the upper edge of the side wall of the fuel storage pool 5 at their upper end near-bending portions, and are spaced vertically at a predetermined horizontal interval with most of the lower part below the pool water surface. are fixed to the side wall of the fuel storage pool 5 in parallel with each other.

A plurality of innermost cylindrical storage rack bodies 22 are fixed vertically and horizontally in parallel in the fuel storage pool 5 with fixing fittings 21 and 21 interposed therebetween. All the storage rack bodies 22 have their back plates 23 and bottom plates 24 fixed with fixing fittings 21.2.
Each of the storage rack bodies 22 and 22 is shared by one plate member whose both ends are fixed to the storage rack body 1, and a required interval is provided between adjacent storage rack bodies 22, 22. The front and top surfaces of the storage rack body 22 are open, and the control rod 17 is inserted through the front opening 25 so that two of the four blades arranged in a cross shape, two of which are located symmetrically, are approximately on the front surface. It has a shape that allows it to be placed in parallel and horizontally introduced into the storage rack main body 22.

At the bottom of each storage rack body 22, a movable receiving plate 26 made of a rectangular plate is horizontally disposed. This movable receiving plate 26 is guided by four guide columns 27 that are provided upright and protruding from the upper surface of the bottom plate 24, so that it can freely move up and down. A stopper washer 28 is fixed to the upper end of the guide column 27, and four stopper protrusions 29 are fixed to the upper surface of the bottom plate 24, and the vertical movement of the movable receiving plate 26 is limited by the stopper washer 28 and the stopper protrusions 29. There is. A movable receiving plate 26 is provided on the outer periphery of each guide column 27.
A 3° support hole 31 is provided for a compression coil spring that constantly urges the spring upward.

On the upper surface of both side edges of the movable receiving plate 26, the lower end of a connecting plate 32 is fixed upright.

It extends upwardly along the upright side plate 33 of the storage rack body 22 and projects upwardly and outwardly from the open upper surface thereof. The connecting plate 32 is made of a leaf spring material, and its upper part is bent into a dogleg shape in cross section, and the outer side of the lower part 34 of the doglegged part
It contacts the inner edge of the upper end of No. 3 and is restrained from moving outward. Further, the upper part of the dogleg-shaped cross section of the connecting plate 32 becomes a gripping part 35, and the gripping part 35 is provided with a through groove 36 for gripping the - of the cross-shaped blades of the control rod 17. It is being On the other hand, a guide plate 37° 37 for guiding the front edge of the connecting plate 32.32 is fixed to the upper end of the side plates 33, 33 of the storage rack main body 22. Storage rack body 2
The introduction into the second section is at an interval above which there is no problem. As described above, even when the upper part of the connecting plate 32 is deformed by the spring, the side plates 33, the back plate 23, and the guide plate 37 prevent the upper part of the connecting plate 32 from coming off to the outside of the storage rack main body 22.

The operation of the control rod storage rack constructed as described above according to Jin's invention will now be described.

The used control rods 17 are lifted up via the handles 18 by remote control using the grips 10 of the fuel exchanger 8 (FIG. 1), and are placed underwater in the reactor well 4 (FIG. 1) and the fuel storage pool 5. is conveyed horizontally into the storage rack body 22 and located in the symmetrical position of the control rod 17 on the front side thereof.
The blades are introduced from the front opening 25 with the blades substantially parallel to each other.

The control rod 17 has a lower end coupling socket portion 19 fitted into the support hole 31 of the movable receiving plate 26, and the movable receiving plate 2
6, the movable receiving plate 26 receives the weight of the control rod 17 and descends against the compression coil spring 30. In conjunction with the lowering movement of the movable receiving plate 26, both the connecting plates 32.32 are lowered, and the lower portion 34.32 of the dogleg-shaped cross section of the connecting plate 32.32 is lowered.
34 is guided by the upper edges of the side plates 33, 33 of the storage rack main body 22 and closes inward, and the movable receiving plate 26 comes into contact with the stopper protrusion 29 to prevent its descent. At this time, the gripping portions 35.35 at the upper ends of the connecting plates 32.32 are closed inward. The control rod 17 is then gripped by the gripping portion 35° 35 at its blade portion via the through groove 36, 36 provided in the gripping portion 35° 35. Then,
Remove the grip 1o from the handle 18. Remove the control rod 1 from the handle 18.
The storage in the controlled expansion storage rack of No. 7 is completed.

Note that the control rods 17 stored in the control rod storage rack
To take out the control rod 17, use the grip 10 to slightly lift the control rod 17 through the handle 18. Then, the movable receiving plate 26
is raised and returned by the compression coil spring 30, and the grip portion 35
．． 35 opens. Therefore, the control rod 17 is moved horizontally,
It can be taken out from the front opening 25.

〔Effect of the invention〕

The control rod storage rack according to the present invention has an innermost cylindrical shape with the front and top surfaces open, and allows the control rods to be introduced horizontally from the open front, so that the control rods can be placed vertically in the fuel storage pool. The storage rack body is fixed to the bottom of the storage rack body, and the bottom of the storage rack body is biased upward and is installed horizontally so that it can move up and down a certain distance, and when the control rod is placed, it is lowered and when the control rod is removed. has a movable catch plate that rises and returns,
The lower ends are fixed to both side edges of the movable receiving plate, and the upper end extends upward and closes in conjunction with the lowering of the movable receiving plate, and can be freely gripped and released to grasp the upper part of the control rod housed in the storage rack body. In order to store the control rods in this control rod storage rack, the control rods are suspended in the pool water by the fuel exchanger, and the control rods are placed in the fuel storage pool. The control rods are stored so that the control rods move at approximately the same depth of water as when they are stored in the storage rack, and the two blades, which are symmetrically located with respect to the control rod's central axis, are approximately parallel to the open front surface of the storage rack body. If the control rod is inserted horizontally into the rack body from its open front side and then lowered and placed upright on the movable receiving plate, the movable receiving plate will lower and the grip at the top of the connecting plate will Grasp the top of the control rod. Therefore, the operator must operate the refueling machine and remotely suspend the control rods in the pool, move them in the pool, introduce them into the storage rack body, place them on the movable receiving plate, and release them. Since the control rods can be correctly stored in the control rod storage rack by simply using the following method, each of the above-mentioned operations necessary for control rod storage can be easily and quickly and remotely performed by the operator without requiring a high level of skill. There is an effect that can be done,
This has the effect of reducing the total amount of radiation exposure for operators, and during rehabilitation, the control rod is firmly supported by the lower end of the movable support plate and the upper end by the grip of the connecting plate, so that the control rod can be easily removed from the storage rack due to vibrations, etc. This has the effect of reliably preventing the main body from falling from the open front surface to the outside.

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of the fuel storage pool and its surrounding area in the reactor building, Figure 2 is a perspective view of a conventional control rod storage rack with control rods stored in it, and Figure 3 is a conventional control rod storage rack. A working diagram when storing control rods in a rack, FIG. 4 shows a control rod and a control rod storage rack according to the present invention, and a partially cross-sectional side view of the surrounding area, and FIGS. 5 and 6 show a control rod according to the present invention. Front view and enlarged plan view of main parts of each storage rack.
FIG. 7 is an enlarged plan view of the main part of the control rod storage rack when the movable receiving plate 26 of FIG. 6 is lowered. 5... Fuel storage pool, 17... Control rod, 19...
・Coupling socket part, 22...Storage rack body,
25...Front open part, 26...Movable receiving plate, 3o...
- Compression coil spring, 31... Support hole, 32... Connecting plate, 35... Gripping portion. (7317) Agent Patent attorney Kensuke Norichika (and 1 other person) Figure 1 Figure 2 Figure 4 Figure 1 Figure 5

Claims (4)

[Claims] (1) Storage that is fixed in the fuel storage pool with the innermost cylindrical shape with the front and top surfaces open, allowing control rods to be introduced horizontally from the open front surface, and with the length direction vertical. The rank body and the bottom of the storage rack body are biased upward and are installed horizontally so that they can move up and down a certain distance, and are movable to lower when a control rod is placed and return to rise when the control rod is removed. A receiving plate, the lower ends of which are fixed to both side edges of the movable receiving plate, and the upper ends thereof extend upward and close in conjunction with the lowering of the movable receiving plate, gripping the upper part of the control rod housed in the storage rack body. A control rod storage rack comprising a connecting plate forming a grip part that can be freely gripped and released. (2) The control rod storage rack according to claim 1, wherein the storage rack main bodies are formed into a plurality of pieces and are integrally connected in parallel with each other at intervals in the horizontal direction. (3) The control rod storage rack according to claim 1 or 2, characterized in that the ITI movable temporary receiving plate has a support hole in which the lower end coupling socket portion of the control rod fits into the center thereof. . (4) The control rod storage rack according to claim 1, 2, or 3, wherein the movable receiving plate is urged upward by a compression coil spring.