JPS5837038Y2 - door valve - Google Patents

Description

[Detailed description of the invention] The present invention relates to a door valve, and is particularly used in fuel handling equipment such as cask cars that transport nuclear reactor core components outside the reactor, such as a cleaning room, to remove sodium adhering to spent core components. The present invention relates to a door valve suitable for effectively storing sodium scattered by dripping or blowing for cooling spent fuel in a drip pan, and preventing scattering of activated sodium.

In conventional cask cars, sodium that drips from spent core components housed in the cask is
A drip pan for accommodating the door valve is provided above the shutter to prevent the function of the door valve from being impaired due to sodium adhesion.

The drip pan is formed in a size that can cover the cask guide pipe with sufficient margin to prevent soot and lithium from scattering into the door valve.

However, in this type of door valve, there is a required gap between the drip pan and the upper flange of the valve body, so it is not affected by forced circulation inside the cask using argon gas to remove heat from the spent fuel. )
There is a drawback that IJium is scattered and a large amount of sodium falls into the valve body from the gap.

To remove and replace the drip pan, either remove the entire door valve, or create an extraction hole in the horizontal direction of the valve body and take it out from this extraction hole.
The work is extremely difficult as the sodium scattered inside the valve body is radioactive and requires measures to prevent exposure to radiation.

Furthermore, since the scattered sodium adheres to the door valve seal surface, the adhering sodium causes deformation, material deterioration, and damage to the door valve seat backing, making it impossible to maintain the seal boundary.

The possibility that the seal boundary cannot be maintained increases as the number of spent core components handled increases.

For this reason, it is necessary to replace the seat backing with a new one each time it occurs, but this replacement work also requires the removal of the entire door valve, just as in the case of drip pans, and it is necessary to consider radiation exposure measures for workers. This is an extremely difficult task.

The present invention was devised in view of the current situation, and its purpose is to prevent sodium dripping from spent core components and sodium scattering due to argon gas blowdown for cooling spent fuel. The purpose is to provide the pan with a door valve that can effectively trap sodium.

This invention focuses on the fact that the conventional difficulty is due to the fact that there is always a required gap between the top surface of the valve body and the drip pan.The present invention focuses on the fact that there is always a required gap between the top surface of the valve body and the drip pan. An operating direction changing mechanism that converts force into force is provided, and this operating direction changing mechanism is activated at the same time as the valve is closed, bringing the drip pan into close contact with the upper surface of the valve body and pressing the shutter against the lower surface of the valve body. This is designed to prevent sodium from scattering.

The present invention will be described below based on a first embodiment.

In the figure, reference numeral 1 denotes a spent core component or a core component such as spent fuel, and this core component 1 is arranged in a cask guide pipe 3 provided in a cask body 2.

A shielding ring 5 is connected to a lower position of the cask body 2 via a door valve 4.

The door valve 4 includes a box-shaped valve body 6, a shutter shield 8 that moves forward and backward within the valve body 6 by driving a drive shaft 7, and a drip pan 9 and a shutter 10 provided above and below the shutter shield 8. It is configured.

The drip pan 9 is detachably fixed to the upper end of an operating rod 11 that vertically passes through the shutter shield 8.
It is configured to move up and down in conjunction with the

A sealing material 12 is provided on the upper edge of the opening of the drip pan 9 to seal the gap with the upper surface of the valve body 6.

On the other hand, the shutter 10 is connected to the shutter shield 8 via a spring 13.13 that biases it in the direction of the shutter shield 8, as shown in the figure, and between the shutter 10 and the shutter shield 8, An operating direction changing mechanism 14 is provided that moves the drip pan 9 and shutter 10 up and down in conjunction with the drive shaft 7.

The operating direction changing mechanism 14 is composed of a double crank mechanism consisting of two arms 14a, 14a whose one ends are swingably connected to each other, and a drive shaft 7 is connected to the connected end of each arm 14a. , and the lower end of the operating rod 11 and the shutter 10 are respectively connected to the free end.

The operating direction changing mechanism 14 is configured to move the operating rod 11 and the shutter 10 up and down in conjunction with the lateral movement of the drive shaft 7.

Note that the spring 13 may be provided anywhere as long as it can bias the two arms 14a in the closing direction.

In the figure, reference numeral 15 denotes a stopper that comes into contact with the shutter 10 to restrict the lateral movement range of the shutter shield 8. The contact surfaces of the stopper 15 and the shutter 10 are cut diagonally, and the movement direction is changed. The structure is such that the shutter 10 can be easily moved downward as the mechanism 14 is operated.

In the above configuration, the shutter shield 8 moves within the valve body 6 by the drive shaft 7 when the core component 1 is handled, and closes the connection opening with the shield ring 5.

When the drive shaft 7 is further pressed in this state, the horizontal force is converted into a vertical force by the operating direction conversion mechanism 14, and the drip pan 9 rises and is separated from the top surface of the valve body 6 via the sealing material 12. While being sealed, the shutter 10
is lowered, and a seal boundary is formed between the lower surface of the valve body 6 and the lower surface of the valve body 6.

After the above operations are completed, the core components 1 are handled.

Then, the dropped sodium and the scattered sodium due to the argon gas blowdown for cooling are removed from the valve body 6.
All of the liquid is collected in the drip pan 9 without being scattered inside.

After the sodium has been collected, when the pressure on the drive shaft 7 is released, the drip pan 9 is lowered by the weight of the drip pan 9 and the biasing force of the spring spring 13, and the shutter 10 is raised.

If the drip pan 9 and the shutter 10 are moved up and down significantly at the position where the connecting hole between the valve body 6 and the shielding ring 5 is closed in this way, the valve can be surely closed.

Furthermore, when the pressure on the drive shaft 7 is released when opening the connection opening, the drip pan 9 and the shutter 10 move up and down due to the action of the spring 13, so only a light load is applied to the drive shaft at this time. Moreover, there is no fear that the drip pan 9 or the shutter 10 may stick to the inner wall of the valve body and become immovable.

Further, when the shutter shield 8 is moved, there is a sufficient gap between the drip pan 9 and the wall of the valve body, so that smooth movement of the shutter shield 8 is not hindered.

Further, when the shutter shield 8 is moved from the open position to the closed position, there is no fear that the shutter shield 8 will stop within the valve body.

In addition, it is convenient because the drip pan 9 can be separated from the shutter shield when discarding drips remaining in the drip pan 9.

According to this embodiment described above, it is possible to effectively collect the dripping IJium and the scattered sodium in the drip pan, and it is possible to effectively prevent the contamination by the radioactive L and Liium in the valve body. can.

As a result, cleaning work and the like during door valve maintenance becomes easier, and it is possible to plan to reduce the amount of radiation exposure.

In addition, since the amount of sodium adhering to the door valve seat surface is drastically reduced, the adverse effects of sodium on the seat backing are eliminated, and the risk of material deterioration, breakage, abnormal deformation, etc. of the seat backing can be reduced.

This increases the number of core components that can be handled and reduces the frequency of door valve maintenance.

FIG. 2 shows another embodiment of the present invention, in which the operating direction changing mechanism 14 is constituted by a three-way fluid pressure cylinder.

A similar effect can be expected even with this configuration, and a similar effect can also be expected even if the operating direction conversion mechanism 14 is configured with a cam mechanism or a link mechanism to convert horizontal force in the vertical direction. can.

The present invention has been described above based on the preferred embodiments. According to the present invention, dripping sodium and scattered sodium from core components are effectively collected in the drip pan, and sodium scattering into the valve body is effectively prevented. can be prevented.

[Brief explanation of the drawing]

FIG. 1 is a cross-sectional view showing one embodiment of the present invention, and FIG. 2 is a cross-sectional view showing another embodiment of the present invention. 1... Core components, 2... Cask body, 3... Door valve, 5... Shielding ring, 6... Valve body, 7... Drive shaft, 8... Shutter shield, 9...
Drip pan, 10...Shutter, 14...
...Actuation direction conversion mechanism, 14 a...Arm.

Claims (1)

[Scope of utility model registration request] A door valve comprising a shutter shield that moves forward and backward within the door valve main body by driving a drive shaft, a drip pan provided at the top of the shutter shield, and a shutter provided at the bottom of the shutter shield. is provided with an operating direction converting mechanism that is linked to the drip pan and shutter and converts the horizontal force of the drive shaft into vertical force, and this operating direction converting mechanism is connected to each other so that one end thereof can swing. It is formed by a double crank mechanism having two arms, the tip of the drive shaft is connected to the connecting part, and a drip pan and a shutter are connected to the free end of each arm, and the direction in which the two arms are closed is The operating direction changing mechanism operates in synchronization with the closing of the valve to bring the drip pan into close contact with the upper surface of the door valve body and to press the shutter against the lower surface of the door valve body. door valve.