JPS6188190A - Elevator of transport vessel for spent nuclear fuel - 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 (Field of medical application) The present invention relates to an improvement in a lifting device for a spent nuclear fuel transport container.

(Prior technology) When transferring spent nuclear fuel to and from spent nuclear fuel transport vessels (hereinafter referred to as casks) at nuclear facilities, etc., the work is carried out underwater to reduce radiation exposure to workers and remove heat generated from the fuel. It is common to do so. On the other hand, complex-shaped fins are often attached to the outside of the cask in order to dissipate the heat generated by the spent nuclear fuel stored therein, but these fins can become contaminated by radioactive materials in the pool water. Various measures have been taken to prevent this.

The countermeasures will be explained in detail with reference to FIG. First, the cask (1)
Before being placed in the pool (9), the fins of the cask (1) are covered with a cylindrical bagging device. There are two types of this bagging device: metallic ones (see (3)) and flexible ones (see (4)). In the case of (3), this bagging device (3) and the cask (
After filling the space between (1) and (5) with fresh water, the overhead crane α
The cask (1) is lowered into the water of the pool (9) by α and placed on the floor of the pool (9). In addition, in the case of a flexible bagging device (4), an overhead crane (10
), the cask (1) is lowered into the water of the pool (9), filled with fresh water, and then placed on the floor of the pool (9). In this case, the pool (9) is deep enough to be shielded even if the fuel is removed from the cask (1), and the hook of the crane (10) must be adjusted according to the water depth to prevent it from entering the water in the pool (9). The underwater hanging device (7) is used.

In addition, the bolt that allows the lid (2) of the cask (1) to be removed has been removed in advance, and the cask (1) is attached to the pool (9).
) When the person lands on the floor 10 of the cask (1) and the hanging tool (6) is detached from the cask (1), only the plow (2) is lifted up by the chain (8) etc. attached to the lifting tool (6). Only one lid (2) is removed from the cask (1) underwater. This lid (
2) is once taken out of the pool (9) and decontaminated until the surface contamination is within the standard value? After that, the pool (
9) It will be temporarily placed in the place where the pheasant was covered. Next, the spent nuclear fuel inside the cask (11) is taken out by a dedicated fuel handling crane, and the spent nuclear fuel is put into the inside of the cask (1).Once the fuel has been taken out and taken out, the overhead crane (101) The lid (2) temporarily placed outside the pool (9) is hoisted up using the and underwater lifting equipment (7), attached to the cask (1) underwater in the pool (9), and the cask ( 1) The lifting tool (6) is engaged with the body and the cask (1) is lifted out of the water.At this time, the exposed surface of the cask (1) and the surface of the bagging material are on the pool (9). It is washed with water and transported to a cask decontamination site, where the bagging equipment is removed and the surface of the cask (1) is decontaminated.

In the elevating device for the spent nuclear fuel transport container described in I, (1) It was inconvenient to handle the cask (11) because it required a long underwater hanging device (force) to handle the cask (11).
) will not be contaminated, but the exposed parts of the cask (1) and the surface of the bagging device will be contaminated by radioactive materials in the pool water. For this reason, washing is done in the pool, but it is difficult to completely decontaminate the water, so we move to a decontamination site and completely decontaminate by wiping, etc.
At this time, there was a risk of contamination spreading to the facility floors. In addition, since the cask (1) and the bagging device (31 (4)) are used repeatedly, it is necessary to completely decontaminate the contaminated area, and this decontamination work requires a lot of time and effort. (1) The bagging equipment was quite large, making it inconvenient to handle multiple units during decontamination.

Various bagging devices are required to accommodate various types of casks having different side external shapes, and therefore, a large space is required to store the bagging devices, which is uneconomical.

(Means for resolving the problem) The present invention addresses the above-mentioned problems by providing a cage that can be raised and lowered along the wall of the pool, and a watertight case installed vertically within the cage. , a seal cover that watertightly closes the gap +i41 between the upper part of the case and the upper part of the spent nuclear fuel transport container stored in the case, and the inner peripheral edge side of the container cover is divided into petal shapes. Adjacent edges of each of the divided pieces are connected to each other so that they can be opened and closed using a waterproof zipper, and an overlapping part of the inner periphery of each divided piece to the central part of the outer side is folded. A gap is formed in the elevating device for the spent nuclear fuel transport container, which is characterized by forming and opening/closingly connecting both sides of the overlapping part with waterproof fasteners. (1) Contamination of the outer surface of the cask can be prevented when unloading or loading. (n) The area contaminated by the pool water taken out of the pool is only the upper part of the cask, which has an extremely small surface area, which prevents the spread of contamination to the facility floor, etc., and makes it easier to decontaminate the cask. can. (11) The upper part of the case can be opened and closed like a petal, making it easy to store the cask in the case. The seal cover at the top of the top case has a pleated overlapped part that allows adjustment of the inner diameter dimension, making it compatible with various casks with different outer diameters.
There is no need to replace the bagging device depending on the type of cask, unlike in the past. (■The cage, which has a case installed to protect the outer surface of the cask, can be lifted up and down, making lifting and lowering easier without the need for long underwater hanging equipment as in the past. An object of the present invention is to provide an improved device for lifting and lowering a spent nuclear fuel transport container.

(Implementation row) Next, the device for lifting and lowering the spent nuclear fuel transport container of the present invention is installed in the first row.
To explain with an embodiment shown in FIGS. 7 to 7, αυ is a pool filled with water, and the inner wall surface is lined with stainless steel. Also, α2 is the pool aυ
A cage that can be moved vertically along guide rails in the water of Pool αυ, and Country α has developed a cage (lift drive device for raising and lowering 121 into the water of Pool αυ, Q = 1) for transporting spent nuclear fuel. A spent nuclear fuel transport container (hereinafter referred to as a cask) (15) is a cask storage case erected inside the elevator cage tlz, and is formed into a cylindrical shape with an eye 9 and a bottom plate. In addition, a seal cover ue whose inner peripheral edge is divided into petal shapes is attached to the upper part of the case (19) in a watertight manner. The inner peripheral edge is divided into petal-shaped pieces as described above, and the adjacent edges of each segment are equipped with waterproof zippers (
17) is installed. Instead, when the waterproof zipper (17) is opened, the seal cover Q6) spreads out like a flower (see Figure 5), and when the waterproof zipper 07) is closed, the seal cover (le is shaped like a truncated cone with closed petals). (See Figure 6).Also, this seal cover u6
) A pleated overlapping portion is provided at the center portion on the inner peripheral edge side of each divided piece. This pleated overlapping portion Oa can be opened and closed by a waterproof zipper (19), and when this waterproof zipper (11) is closed, the pleated overlapping portion QFj is folded and confined inside, further increasing the inner diameter. It becomes thinner (see Figure 7).

Therefore, by increasing or decreasing the number of parts closed by the waterproof fastener H, the inner diameter of the truncated conical seal cover 00 can be adjusted stepwise. As a result, the gap between the upper part of the case Q51 and the upper part of the cask 041 can be sealed watertightly even for various casks I having different outer diameters by using the same seal cover ue. In addition, (4) is a flexible hose for supplying fresh water to the space formed by the surface of the cask Q4), the case body <15), and the 7-rule cover 16j, and the flexible hose I20) supplies fresh water to the space. and fill it up to 6.

(Function) Next, the function of the cask (spent nuclear fuel transport container) described in 11J will be explained. First, to explain the preparation state for removing the receiver on the cask side, the elevator cage α2 and the case u9 stop at the highest position of the pool 0υ, and the seal cover (waterproof fastener outlet provided on the adjacent edge of the divided piece of IQ) is opened. The seal cover (16) is opened and each segment of the seal cover (16) is waiting in an expanded state.Then, the cask I is lifted up by an overhead crane or the like (not shown) in the gun installation and placed in the elevator cage α2. The case body (l) provided in Seal cover (1G) to protect the surface
Close the waterproof zipper α7) attached to the Next, until the outer periphery of the cask side and the inner diameter of the inner periphery of the seal cover (16) are approximately equal, a folded overlapping part (1a) is provided on the seal bar aυ so that it can be folded over and kept inside. Close the appropriate number of waterproof zippers (11).

If the outer diameter of the cask (14) is small, a large number of waterproof fasteners α■ may be closed, and if the outer diameter of the cask (14) is large, a small number of waterproof fasteners α→ may be closed. Although not shown, the watertightness of this part can be determined by wrapping an elastic packing around the outer periphery of the cask U4 in advance.
Secure the waterproof zipper (1G) by wrapping an elastic band or pasting tape over the closed seal cover 161. Next, supply fresh water with a flexible hose and close the cask (1□0) The space formed between the surface and the case t15) and the seal cover (10) is filled with clean water. After the above work is completed, the elevating drive device shouts to move the case α9 containing the cask (14) together with the elevating cage a2. It is lowered to the deepest part of the pool (Ql).After this, the spent nuclear fuel is removed or loaded into the cask side using a fuel handling crane (not shown) in the same way as in the past. If loading or unloading is completed, you can perform the work in the reverse order.

(Effects of the Invention) The device for lifting and lowering the spent nuclear fuel transport container of the present invention includes a cage that can be moved up and down along the wall of the pool, as shown in section 6'tJ, and a watertight case installed vertically within the cage. It has a cover that watertightly closes the gap between the upper part of the case and the upper part of the transport container for fuel bales stored in the same case, and the inner peripheral edge of the cover is divided into petal shapes. At the same time, the adjacent edges of each of the same pieces are connected so that they can be opened and closed by a waterproof zipper, and a pleated overlapping part is formed at the center of the inner peripheral edge of each piece of the same piece, and the overlapped part is Both side edges are connected so that they can be closed by waterproof fasteners, and the following effects are achieved, so that the following effects can be achieved. That is, when spent nuclear fuel is taken out or loaded into the cask in the pool water, (I) it is possible to prevent the outer surface of the cask from being contaminated by radioactive substances in the pool water; (It) The inner edge of the seal cover, which is watertightly attached to the top of the Yayask storage case, is divided into multiple pieces like flower petals (/(), and a waterproof zipper is attached to the adjacent line of each divided piece. Line 9 can be inserted into and taken out of the case and the seal cover. (If
) A fold-like overlapping part is provided at the middle arrow part of the inner peripheral edge 9111 of each divided piece of the seal cover, and waterproof zippers that can be opened and closed are provided on both sides of the overlap part to adjust the inner diameter of the caltrop and seal cover in stages. can.

Therefore, the same seal cover can be used for various types of casks with different outer diameters, and there is no need to prepare multiple types of 7-capers to match the types of casks, as was the case in the past.

■The cask storage case and seal cover are installed in a lifting cage that always moves up and down along the pool wall, eliminating the need to take out the bagging device that came into direct contact with the pool water outside the pool, unlike in the past. The area contaminated by the pool water taken out of the pool is only the upper part of the cask, which has an extremely small surface area, making it possible to prevent the spread of contamination to the facility floor, etc., and to facilitate decontamination work. Until now, the bagging equipment had to be decontaminated in order to be reused, which required a great deal of effort. Note that the air space 1"i'+ formed by the cask, case, and seal cover
The fresh water to be filled is not limited to fresh water, but may be other liquids, gases, or semi-solids such as jelly.
Even if the seal is imperfect, pool water will not be able to enter this space by applying some pressure.

Although the present invention has been described above with reference to embodiments, it goes without saying that the present invention is not limited to such embodiments, and that various design modifications can be made without departing from the spirit of the present invention. .

[Brief explanation of the drawing]

FIG. 1 is a plan view showing a state immediately after the cask receiver is inserted into the case at the top of the pool of an embodiment of the device for lifting and lowering a spent nuclear fuel transport container according to the present invention, and FIG. 2 is a side view at that time. Fig. 3 is a plan view showing the state when nuclear fuel is taken in and out of the cask at the deepest part of the pool, Fig. 4 is a side view at that time, Fig. 5 is a perspective view showing the expanded state of case cuff e-, Fig. 6 7 is a perspective view of the case cover when the divided pieces are closed, FIG. 7 is a perspective view of the case cover when the divided pieces and part of the overlapping part are closed, and FIG. 8 is a perspective view of a conventional spent nuclear fuel transport container. It is a 11111 side view showing the elevating device. Uυ...Pool ari...Cage 0 (A)...Spent nuclear fuel container α9...Case 0e...
・Seal turtle - 0'? )...Waterproof fastener α that connects the adjacent edges of the divided pieces of the seal cover (16) in an openable and closable manner.Overlapping portion α-cap: A waterproof fastener that connects both sides of the overlapping portion U in an openable and closable manner. Temporary agent Patent attorney Shige Okamoto 3 people outside of the text 1st image 3rd @ 5th and 6th figure

Claims (1)

[Claims] The gap between the cage that can be raised and lowered along the pool wall, the watertight case installed vertically inside the cage, and the top of the case and the top of the spent nuclear fuel transport container stored in the case is and a seal cover that closes in a watertight manner, the inner peripheral edge of the seal cover is divided into petal shapes, and the adjacent edges of each divided piece are connected so as to be openable and closable with a waterproof zipper,
A device for lifting and lowering a spent nuclear fuel transport container, characterized in that a pleated overlapping portion is formed at the center of the inner peripheral edge of each divided piece, and both side edges of the overlapping portion are openably and closably connected by a waterproof fastener.