JPH0222719Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a damaged fuel storage container for storing defective fuel used in a nuclear reactor of a nuclear power plant.

After the fuel used in the reactor of a nuclear power plant is removed from the reactor, it is inspected for defects in an inspection pit in the fuel handling building adjacent to the reactor containment vessel, and defects are discovered. The items are stored in a damaged fuel storage container in a spent fuel pit in the same building. As shown in Figures 1 and 2, the damaged fuel storage container a is placed in a damaged fuel rack c, which is separate from the spent fuel rack b, underwater in a spent fuel pit in a fuel handling building. Therefore, the lid of the damaged fuel storage container a must be removed underwater at a depth of approximately 10 meters, and the damaged fuel must be stored using a crane that travels over the spent fuel pit, and then the lid must be replaced. As shown in Figures 3, 4, and 5, the damaged fuel storage container a is made up of a main body 1, a basket 2 containing the damaged fuel, a main body flange 3, a lid 4, and a gripper suspended from a crane to grasp and pull up the lid 4. A center guide pin 6 (two pieces) for aligning the center of the lid 4 with the center of the main body flange 3 is fixed to the main body flange 3, and the main body flange 3 and the lid 4 are connected to each other. Many (10 in the drawing)
The hinge bolt 7 and nut 8 of the set are tightened and fixed. A pin 10 passing through a hole at one end of the hinge bolt 7 is attached to a mounting bracket 9 fixed to the main body 1, and the hinge bolt 7
is rotatable in the radial direction about the pin 10.
The main body flange 3 and the lid 4 are provided with a notch on the outer periphery so that the hinge bolt 7 does not interfere with falling down. For the hinge bolt 7, loosen the nut 8 as shown in Figures 6, 7, and 8.
When the lid 4 is removed, it will fall down until it hits point A by the force of the spring 11. Then, when the lid 4 is brought closer to the main body flange 3, the pin 12 attached to the lid 4 will pass through the hole 13 of the main body flange 3 and come out from the bottom surface. Get out. At this time, when the B surface of the base of the hinge bolt 7 is pushed inward in the radial direction, the hinge bolt 7 gradually stands up against the force of the spring 11, and stops when it becomes almost vertical. At that time, the nut 8 must be in a position where it does not get caught on the edge of the lid 4.

In the damaged fuel storage container, when removing and installing the lid 4, a worker on the deck of a pit crane traveling over the pit loosens the nut 8, which is in fairly deep water, by turning a long nut handling tool. I have to tighten it, but Natsuto 8
When loosening the hinge bolt 7, the tip of the pin 12
When the hinge bolt 7 tries to fall down due to the force of the spring 11 after separating from the B side of the base, a large number of nuts 8 must be screwed up to the point where they do not catch on the edge of the lid 4, and conversely, the lid 4 When tightening, a large number of nuts 8 must be unscrewed, and the nut handling tool must be turned a large number of times, which requires a lot of time. Furthermore, when installing the lid 4 by hanging it by a crane, the worker must look down from the deck of the crane and align the center guide pin 6 of the flange 3 with the hole in the lid 4, but the center guide pin 6 is hidden by the lid 4. Since it cannot be seen, it has the disadvantage that alignment takes a lot of time.

This proposal addresses the above-mentioned problems, and includes a forked guide member, an engaging member that engages with the guide member, and a lid that is inserted into the bolt hole of the lid from above to attach the lid to the damaged fuel storage container. The damaged fuel has a holding bolt with a retaining ring that is detachably fixed to the main body flange, and the guide member and the engaging member are provided at at least two locations on the outer periphery of the lid and the main body flange. Regarding the storage container, the purpose thereof is to shorten the time for tightening and unscrewing the bolts that tighten and fix the lid to the main body flange. Another object of the present invention is to provide an improved damaged fuel storage container that can shorten the alignment time between the main body flange and the lid.

Next, the damaged fuel storage container of this case is shown in Figures 9 to 1.
To explain with an example shown in FIG.
In figure 0, 1' is the main body, 2' is the main body flange, 3' is the lid,
4' is a top nozzle on the lid 3' side that is used to lift the lid 3' by hooking it with a gripper suspended by a crane.
Attach the lid 3' to the main body flange 2' using the retainer bolt 5'.
The guide member 6' attached to the outer periphery of the main body flange 2' for the center guide and the engaging member 7' attached to the outer periphery of the lid 3' are engaged. It shows. These members 6', 7' are provided at at least two locations as far apart as possible. Details of the installation of the presser bolt 5' and the above-mentioned members 6' and 7' are shown in Figs. 11 to 1.
It is shown in Figure 4. The holding bolt 5' is inserted into a bolt hole of the lid 3', and a retaining ring 8' is attached by screwing or the like. The tip of the holding bolt 5' is
It has a conical shape with a rounded apex. Further, the screw hole 9' of the main body flange 2' into which the presser bolt 5' is screwed has a tapered part formed at its upper end.
The holding bolt 5' can be smoothly inserted into the screw hole 9'. Also, the retaining ring 8' attached to the holding bolt 5' to prevent it from falling out from the bolt hole 3'' interferes with the lid 3' when the lid 3' is placed on the main body flange 2' (see Figures 15 and 16). To prevent this, a cavity 10' is formed in the lid 3'.
The cavity 10' has a height such that even if the tip of the holding bolt 5' hits the screw hole 9' and is lifted, it does not hit the retaining ring 8'. Once the lid 3' is aligned with the main body flange 2', a worker fits the tip of a long handling tool into the head of the holding bolt 5' from the deck of the pit crane running over the spent fuel pit. Turn it and screw the holding bolt 5' into the screw hole 9'. In this case, since it is only necessary to screw in the length required for tightening (the height of the nut corresponding to the minimum bolt diameter), the screwing time can be significantly shortened. The time for unscrewing the retaining bolt 5' to remove the lid 3' is likewise reduced. This presser bolt 5' does not require modification to match the actual item. A bifurcated guide member 6' is attached to the outer periphery of the main body flange 2', and an engaging member 7' that engages with the guide member 6' is attached to the outer periphery of the lid 3'. The mounting positions of each member 6' and 7' are as follows:
These are at least two locations as far apart as possible on the outer periphery of the main body flange 2' and the lid 3'. The guide member 6' for alignment is bifurcated, and a taper is formed on the inside of the tip to make it easier for the engaging member 7' to enter, and the tip of the engaging member 7' is also tapered. There is. Since the guide member 6' is attached to the outer periphery of the main body flange 2', when the worker looks down from above, the guide member 6' is not hidden behind the lid 3', and alignment work can be easily performed. It can be done.

The damaged fuel storage container of this case is constructed as described above, and the number of times the bolt handling tool is turned when tightening or unscrewing the bolts that fix the lid to the main body flange is significantly reduced, and it is also used for centering the lid. Since the guide member and the engagement member are easily engaged, it is possible to shorten the time required to tighten and unscrew the bolts that tighten and fix the lid to the main body flange, and to reduce the time required to center the main body flange and the lid.

[Brief explanation of the drawing]

Fig. 1 is a plan view showing an outline of a conventional damaged fuel storage container, Fig. 2 is a side view thereof, Fig. 3 is a plan view showing details thereof, Fig. 4 is a vertical side view thereof, and Fig. 5 is a side view thereof. 4. Cross-sectional plan view along the arrow line in Figure 4, No. 6
The figure is an enlarged plan view of the lid, Figure 7 is an enlarged side view of the lid and main body flange, Figure 8 is another side view, and Figure 9 is the storage of damaged fuel related to this proposal. A plan view showing one embodiment of the container, the first
0 is a vertical side view thereof, FIG. 11 is an enlarged side view of the lid portion, FIG. 12 is another longitudinal side view thereof, and FIG. 13 is an enlarged side view of the main body flange portion. Figure 14 is its vertical and side views, the first
FIG. 5 is a side view showing the engaged state of the guide member and the engaging member, and FIG. 16 is a longitudinal sectional view and the other side view. 1'...Body of damaged fuel storage container, 2'...Body flange, 3'...Lid, 5'...Holding bolt, 6'
...Guide member, 7'...Engaging member, 8'...Retaining ring.

Claims (1)

[Scope of utility model registration request] Includes a forked guide member, an engaging member that engages with the guide member, and a retaining ring that is inserted into the bolt hole of the lid from above and removably fixes the lid to the main flange of the damaged fuel storage container. 1. A broken fuel storage container, characterized in that the guide member and the engaging member are provided at at least two locations on the outer periphery of the lid and the main body flange.