JPS5816719B2 - Stopper device for transferred fuel in nuclear reactor transfer assemblies - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a transfer chute that is installed at the inner and outer boundaries of a reactor containment vessel to deliver and transfer fuel. This invention relates to a supported stopper device, and its purpose is to provide a novel stopper device that is excellent in both reliability and maintainability.

First, an overview of the transfer chute in the previous nuclear reactor.
The diagram will be explained.

In the figure, 1 is a reactor containment vessel housing a reactor core 2, and 3 is an adjacent fuel handling building.

A fuel exchange pool 4 is defined on the side of the reactor containment vessel 1, and a fuel exchange machine 5 is installed under the floor of the pool 4 so as to be movable between it and the reactor core 2.

Note that 6 is a fuel inlet/outlet machine, and 7 is a transfer port that penetrates the floor of the pool 4.

On the other hand, the building 3 is equipped with a fuel delivery pool 8 located at a lower level than the fuel exchange pool 4, and a spent fuel storage pool that is not produced domestically.

Note that 9 indicates a fuel transfer machine and 10 indicates a cask crane.

By the way, the fuel exchange pool 4 and the fuel delivery boo
A transfer chute 11 for delivering and transferring fuel is installed slantingly between the fuel tank and the fuel tank.

The upper and lower ends of the transfer chute 11 are provided with isolation valves 12 and 13, respectively, and a rail is laid within the chute.

The fuel to be transferred is stored in a dedicated transfer container 14 that is equipped with wheels and runs on the rails, and is transferred up and down within the transfer chute.

Although not shown, swing devices for tilting the transfer container 14 from an inclined position to a vertical position are provided in the upper and lower pools 4 and 8.

The transfer system for new fuel and spent fuel in a nuclear reactor is well known, and will not be discussed here, but especially for the transfer of fuel that straddles between the reactor containment vessel 1 and the fuel handling building 2. Delivery is performed via the transfer chute 11 described above.

The fuel is delivered in the transfer chute 11 as follows.

For example, after fresh fuel is stored in the transfer container 14 in the pool 8, first only the lower isolation valve 13 is opened and the new fuel is pushed into the transfer chute 11 from below using the transfer carriage.

Subsequently, after closing the valve 13, the upper isolation valve 12 is opened, and the gripper of the transfer carriage is suspended from above via a rope to grasp the transfer container 14 and pull it up.

Valve 12 is then closed again. Also, the spent fuel is transferred in the reverse order.

By alternately opening and closing the upper and lower isolation valves in this manner, simultaneous communication between the pools 4 and 8 is avoided, and isolation between the reactor vessel side and the fuel handling building side is maintained.

By the way, in order to transfer fuel by alternately opening and closing the isolation valves 12 and 13 as described above, it is necessary to disconnect the transfer carriage and the transfer container 14 while the transfer container 14 is inserted into the transfer chute 11. Transfer container 14 to release
It is necessary to temporarily stop and support the transfer shoe at the lower end area within the transfer shoe.

For this purpose, it has already been proposed to provide a stopper 15 located slightly above the lower isolation valve 13 in the transfer chute 11 and operated from the outside to temporarily stop and support the transfer container 14.

However, since this lever stopper is installed in a place that cannot be accessed by people, it must be operated reliably by remote control, and must also be durable and safe.

In addition, the stopper also has a function to stop the transfer container 14 before it collides with the lower isolation valve 13 in the event that fuel falls from above due to an unexpected accident, so consideration must be given to this point.

Further, the stopper operating mechanism is preferably installed outside the transfer chute 11 from the viewpoint of maintenance, but especially when the lower isolation valve 13 is closed and the upper isolation valve 12 is open, the shaft of the stopper operating mechanism is located outside the transfer chute 11. The formation of a pressure boundary on the inside of the furnace at the point where the chute 11 is penetrated becomes a problem.

In view of the above points, the present invention aims to provide a novel stopper device that satisfies various conditions required for a stopper device and has excellent reliability and maintainability.
The configuration of the present invention will be explained in detail below based on illustrated embodiments.

FIG. 2 is a structural sectional view of an embodiment of the present invention, in which a transfer container 14 containing fuel and being moved up and down within the transfer chute 11 as shown by arrow A is stopped and supported by a stopper. Indicates the state in which

Note that rails, wheels, etc. for the transfer container 14 are not shown for simplicity.

Now, according to the present invention, the stopper device is roughly divided into two parts: inside the transfer chute 11, from the side, as shown by arrow B, the transfer container 14
The stopper body 16 (l!l-main components are fixedly installed outside the transfer chute 11 and is operated to move the stopper body 16 in the direction of arrow B). It consists of a stopper operation mechanism 17.

As will be described in detail later, the operating mechanism 17 is constructed with a special mechanism that forms a pressure boundary with respect to the inside of the furnace.

First of all, the stopper body 16 is a cylindrical body whose upper surface is locked to the flange 14a of the transfer container 14, and the stopper body 16 itself is a guide roller 1 installed in the transfer chute 11.
8 and guide ring 19 independently.

On the other hand, the stopper operating mechanism 17 includes an operating rod 21 connected to the stopper body 16 via a flexible joint 20 having an elongated hole, and a valve stem connected to the stopper body 16 with a pin.
A biasing coil spring 22 is connected to the rear of the operating rod 21 so as to bias the stopper body 16 in the forward direction, and an external hydraulic pressure source controls the stopper body 16 to move the stopper body 16 backward against the spring 22. The valve seat flange 2 is composed of an inner and outer double concentric bellows 24.25 communicating with the pressure water pipe 23 connected through the valve, a valve seat flange 26, a case 21, etc.
6. The case 27 is fixed to the transfer chute 11 by tightening bolts 28 so as to close the opening thereof.

The operating rod 21 is configured as a valve stem with a valve body portion 21a formed in the middle, and a flange 21 at the rear.
It is equipped with b.

Further, the rear end of the operating rod 21 protrudes from the case 2γ,
A link of the operating position detection mechanism 29 is provided here.

The biasing spring 22 is compressed and interposed between the case 2γ and the operating member 21.

In addition, single bellows 24 and 25, which are arranged concentrically inside and outside, are installed between the cylinder flange 30 and the rear flange 21b of the operating rod 21, and surround the portion where the operating pressure nozzle 21 protrudes outward from the transfer chute 11. and sealed.

The pressure water piping 23 connects to the internal space 3 defined between the inner and outer bellows 24 and 25 through a groove in the cylinder flange 30.
A communicating opening is provided in the interior of the housing.

Further, the valve seat flange 26 faces the valve body portion 21a,
In particular, the position facing the valve body portion 21a is set so that the valve is closed when the stopper body 16 is advanced to the stop position.

With this configuration, when water is not pressurized and supplied to the internal space 31 between the bellows, the operating rod 21 is biased by the spring 22.
The stopper body 16 advances to the left through the valve body 21a, and at the same time, the valve body portion 21a is pressed against the valve seat 26 to close the valve, thereby forming a pressure boundary for the transfer chute 11 at this valve portion.

When water is supplied under pressure from this state, the operating rod 21 is moved to the right against the spring 22, and the stopper body 16 is moved back.

Next, the operation of the stopper device having the above configuration in connection with fuel transfer will be described.

First, when the lower isolation valve 13 in FIG. 1 is opened to transfer new fuel, the stopper body 16 is in a retreat standby state, and when the transfer container 14 has almost passed through the stopper body 16, the water in the bellows internal space 31 is removed. By lowering the pressure, the stopper body 16 is advanced to support the transfer container 14 from below.

In this case, all the load applied to the stopper body 16 is applied to the guide ring 19 and the guide roller 18, and is not transmitted to the stopper operation mechanism due to the intervention of the flexible joint 20.

Next, after the gripper between the lower transfer carriage and the transfer container 14 is separated and the isolation valve 13 is closed, the upper isolation valve 12 inside the furnace is opened and the gripper of the transfer carriage is lowered from the upper fuel exchange pool side.

In this state, the inside of the transfer chute 11 communicates with the pool inside the furnace, but in the stopper device 15, the valve body portion 21a of the operating rod 21 is pressed against the valve seat 25 and closed, and this portion can withstand the pressure. Water leakage is prevented.

In other words, a pressure boundary is formed for the reactor containment vessel.

Conversely, when transferring spent fuel downward, the stopper body 16 is moved forward and on standby in advance, and the upper isolation valve 12 is opened and the suspended transfer container 14 is temporarily stopped and supported by the stopper body 16. .

In this case as well, the in-furnace pressure boundary is ensured by the stopper operation mechanism, as described above.

Next, after removing the upper transfer carriage and closing the upper isolation valve 12, the lower isolation valve 13 is opened and when the lower transfer carriage grips the transfer container 14, the stopper body 16 is operated to retreat.

Note that the operating position of the stopper body 16 is detected outwardly via the detection mechanism 29.

According to the stopper device having the above-mentioned configuration, when the upper isolation valve 12 is in the open state as described above, the stopper device is operated so as to always ensure the pressure boundary to the inside of the furnace.

In addition, the load, impact, etc. applied to the stopper body 16 is guided by the guide mechanism provided on the transfer shoe 1 side independently, and is connected to the operating mechanism 17 via the flexible joint 20, so that the stopper body There is no risk of excessive load being applied to the operating mechanism 17.

Furthermore, even if a scratch occurs on the valve surface of the valve seat 26 or the valve body 21a, the rear area is backed up by the double inner and outer bellows 24 and 25 that hermetically surround the operating land 21, so water will not leak out. This can be prevented, and even if the operating pressure drops due to damage to the pressurized water supply pipe 23, the valve body portion 21a will remain in place of the valve seat 2.
6 and ensures the formation of a pressure boundary, resulting in high safety.

In addition, since water pressure is used as one driving source, it is convenient because it can be matched to the atmosphere in the pool.

In addition, in terms of maintenance, the entire device is equipped with one guide roller.
It can be removed from the transfer chute 11 as a whole except for 8, making it easy to perform maintenance and inspection when necessary.

As described above, according to the present invention, it is possible to provide a dog stopper device that is highly safe, reliable, and has excellent maintainability and is of practical value.

[Brief explanation of the drawing]

FIG. 1 is a structural sectional view of a nuclear reactor, and FIG. 2 is a structural sectional view of a stopper device based on an embodiment of the present invention. 1...Reactor containment vessel, 3...Fuel handling building, 4...-m exchange pool, 8...Fuel delivery pool, 11...・Transfer chute,
12, 13... Upper and lower isolation valves, 14...
- Transfer container for storing fuel, 15...stopper device, 16...stopper body, 11...
Stopper operation mechanism, 18, 19... Stopper body guide mechanism, 20... Flexible joint, 2
1...Operating rod, 21a...Valve body portion, 22...Biasing spring, 23...Pressure water piping, 24, 25...・Double inner and outer bellows, 2
6... Valve seat flange, 27... Case, 28... Tightening bolt, 31... Internal space partitioned between the inner and outer double bellows, A...
Transfer direction of the transfer container in the transfer chute, B.
...Forward and backward directions of the stopper body.

Claims (1)

[Claims] 1.In order to deliver and transfer new fuel and spent fuel between the high-level fuel exchange pool in the reactor containment vessel and the low-level fuel delivery pool in the fuel handling building, the pool is arranged at an angle and straddles between the two pools, and is installed at the upper and lower ends. A stopper device for temporarily stopping and supporting a transfer container for passing fuel located in a transfer chute in a lower fuel delivery pool area for a transfer chute each equipped with an isolation valve, the stopper device in the transfer chute passageway It consists of a stopper body that can move forward and backward toward a position from the side, and a stopper operating mechanism that is coupled to the stopper body and operates the stopper body to move forward and backward, and the stop body is connected to a guide provided in the transfer chute. The stopper operating mechanism is independently supported and guided by a mechanism and has a built-in flexible joint, and the stopper operating mechanism has an operating rod whose tip is connected to the flexible joint and itself has a valve body part in the middle, and a valve body part of the operating iron. A valve seat flange is fixed to the transfer chute so as to close the valve at the forward operating position of the stopper body, a biasing spring connected to the operating rod so as to always bias the stopper body in the forward direction, and a biasing spring that resists the biasing spring. The interior compartment space is connected to a drive fluid water pressure source so as to move the stopper body backward from the stopper position, and the inner and outer double inner and outer compartments are connected to the operating iron, the internal compartment space of which is connected to the operating iron that seals and surrounds the operating iron that protrudes outward from the transfer chute. A stopper device for transferred fuel in a transfer chute of a nuclear reactor, comprising a concentric bellows.