JPH0695153B2 - Nuclear power plant fuel handling equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Industrial field of application) The present invention relates to a nuclear power plant fuel handling facility for handling highly radioactive substances such as fuel in a nuclear power plant.

(Prior Art) As a facility for handling highly radioactive substances such as fuel in a fuel pool of a nuclear power plant, there are a fuel exchanger, a fuel channel attach / detach machine, and the like. In these facilities, workers board a workbench installed above the water surface of the fuel pool, pull up the fuel in the fuel pool while monitoring the pool water,
Transferred to a designated place. Since the fuel is pulled up in this way, it is necessary to prevent the workers on the workbench from being exposed to the radiation. Therefore, the fuel pulling upper limit position is set to secure the shielding water depth. A shielding water depth monitoring device that secures this shielding water depth is provided in the above fuel handling facility.

For example, when the fuel handling facility is a fuel exchanger, the fuel gripping tool for gripping the fuel is configured to be vertically movable in the fuel pool. This vertical movement is performed by a wire winder via a wire. Then, as a shield water depth monitoring device, a limit switch is attached on the axis of this wire winder, and when the fuel gripped by the fuel gripping tool reaches the pulling upper limit position, the limit switch sends a stop signal to the wire winder. Will be sent. That is, as shown in FIG. 4, when the limit switch 3 of the shield water depth monitoring device 1 is turned ON, the monitoring signal transmission relay 5 is excited and the monitoring signal transmission switch 7 is turned ON. When the monitoring signal transmission switch 7 is turned on, the winding stop signal transmission relay 9 is excited, a winding stop signal transmission switch (not shown) is turned on, and a stop signal is transmitted to the wire winding machine.

(Problems to be Solved by the Invention) However, the shield water depth monitoring device 1 includes the limit switch 3
In addition, since there is no means for stopping the wire winder, if the limit switch should fail, the shielding water depth cannot be secured and the worker may be exposed.

Further, the shield water depth secured by the limit switch is assumed to be the radiation dose emitted from the fuel to be pulled up, and is uniformly determined based on this assumed radiation dose. Therefore, if the radiation dose of the lifted fuel is higher than the assumed radiation dose, the worker may be exposed even if the set shielding water depth is secured.

The present invention has been made in consideration of the above facts, and an object of the present invention is to provide a nuclear power plant fuel handling facility capable of preventing exposure of workers in handling highly radioactive substances such as fuel. .

[Structure of Invention]

(Means for Solving the Problems) In order to achieve the above object, the present invention provides a fuel handling jig that is movable in a vertical direction in a fuel pool and supports fuel at a tip portion, and the fuel handling jig. A fuel handling jig drive device for moving the handling jig, a detector for detecting that the fuel supported by the fuel handling jig has risen to a preset shielding water depth, and a fuel handling jig supported by the fuel handling jig. A radiation dose detector for detecting that the radiation dose from the rising fuel has reached a predetermined value is provided, and a stop signal is transmitted to the fuel handling jig drive device by the operation of the detector and the radiation detector. It has a shielding water depth monitoring device.

(Operation) Therefore, the present invention detects the preset shielding water depth by the shielding water depth monitoring device, sends a stop signal to the fuel handling jig driving device to secure the shielding water depth, and supports the fuel handling jig. When the radiation dose from the stored fuel is actually detected and the radiation dose reaches a predetermined value, a stop signal is transmitted to the fuel handling jig driving device even when the set shielding water depth is not reached.

Embodiment An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a side view showing an embodiment of a nuclear power plant fuel handling facility according to the present invention applied to a fuel exchanger.

The refueling machine 11 is movably installed on the refueling floor 15 near the fuel pool 13. The refueling machine 11 includes a base 17, a work table 19, a wire winder 21 as a fuel handling jig driving device, and a fuel gripper 23 as a fuel handling jig.

The base 17 is movably provided on the refueling floor 15. A work table 19 on which a worker 25 enters is placed on the base 17. The workbench 19 is configured to be movable on the base 17. A wire winder 21 is installed on the ceiling of the workbench 19, and a fuel gripper 23 is attached to the workbench 19 via the wire winder 21.

The fuel gripper 23 is a mast 27 that telescopically expands and contracts.
And a hook 29 arranged at the tip of the mast 27. The fuel 31 is gripped by the hook 29. A wire is built in the mast 27, and this wire is wound or unwound by the wire winder 21,
The mast 27 can be expanded and contracted. Therefore, the fuel 31 is grasped by the hook 29, vertically moved up and down in the fuel pool 13 by the expansion and contraction of the mast 27, and further horizontally moved in the fuel pool 13 by the movement of the work table 19.

By the way, the fuel 31 is a highly radioactive substance, and the fuel gripper 23
Therefore, it is necessary to prevent the worker 25 from being exposed to this radiation. Therefore, the fuel withdrawing upper limit position is determined and the shielding water depth 33 is set. The shielding water depth 33 is assumed to be the radiation dose of the fuel 31, and is set uniformly as the water depth to which the worker is not exposed even by this assumed radiation dose. Then, in order to secure this shielding water depth 33, a shielding water depth monitoring device is provided in the fuel exchanger 11.

This shield water depth monitoring device 36 (Fig. 2) is used for the wire winder 21.
Limit switch 37 (Fig. 2) mounted on the axis of
And a radiation dose detector 35 attached to the lower part of the work nineteen with the monitoring surface facing downward, and configured as shown in FIG. The limit switch 37 is turned on when the fuel 31 gripped by the fuel gripper 23 rises to a preset shielding water depth 33 position. Also, the radiation dose detector 35
The radiation dose detector switch 38 is turned on when the fuel 31 gripped by the fuel gripper 23 rises and the radiation dose from the fuel 31 reaches a predetermined value (estimated radiation dose).

The limit switch 37 and the radiation dose detector switch 38 are connected in parallel, and the monitoring signal transmitting relay 39A is excited by turning ON either one of them. By exciting this supervisory signal transmission relay 39A, the supervisory signal transmission relay switch 3
9B is turned on, the winding stop signal transmission relay 41 is excited, and the winding stop signal transmission switch (not shown) is turned on. As a result, the wire winder 21 stops winding the wire.

Therefore, in addition to the limit switch 37, the radiation dose detector
Since the stop signal can be output to the wire winder 21 also by the 35, even if the limit switch 37 fails, the radiation dose detector 35 can secure the shield water depth 33. As a result, it is possible to reliably prevent the worker from being exposed to radiation.

Furthermore, since the radiation dose is actually detected by the radiation dose detector 35 and a stop signal is transmitted to the wire winder 21 when the radiation dose reaches the expected radiation dose, the radiation dose of the fuel 31 is Is greater than the expected radiation dose, the lifting operation can be stopped even when the fuel 31 does not reach the shielding water depth 33 during the lifting operation of the fuel 31 of the fuel exchanger 11. Therefore, even when the radiation dose of the fuel 31 is higher than the expected radiation dose, the worker can be reliably prevented from being exposed to radiation.

FIG. 3 is a side view showing another embodiment of the nuclear power plant fuel handling equipment according to the present invention, which is applied to a fuel exchange channel. In the other embodiments, the same parts as those in the above embodiment are designated by the same reference numerals and the description thereof will be omitted.

In general, spent fuel taken out of the reactor is primarily stored in a fuel pool and then delivered to a fuel reprocessing plant. The fuel channel attaching / detaching machine is used for separating the fuel into a fuel bundle and a channel box as a pre-process to be carried out to the fuel reprocessing plant. The fuel channel attachment / detachment machine 43 is configured to include a movable table 45, a movable table guide part 47, a work table 49 attached to the upper part of the movable table guide part 47, and the like.

The movable table guide portion 47 is attached to the side wall 51 of the fuel pool 13, and its longitudinal length is set to be substantially the same as the side wall 51. The movable table 45 is provided so that the fuel 31 can be placed on it, and is attached so as to be vertically movable along the movable table guide portion 47. In addition, this movable base 45 has a chain 53
Is fixed. The chain 53 is wound or unwound by a chain winder 55 installed at the bottom of the work table 49.

In such a fuel channel attachment / detachment machine 43 as well, in order to secure the shielding water depth 33, a shielding water depth monitoring device 36 (FIG. 2) having the same configuration as that of the above embodiment is arranged. Of these, the limit switch 37 is mounted on the shaft of the chain winder 55, and the radiation dose detector 35 is fixed to the lower part of the chain winder 55 with the monitoring surface facing downward.

The fuel channel attachment / detachment is performed by using the fuel channel attachment / detachment device 43 and the fuel exchange device 11 of the above-described embodiment or another fuel exchange device.

That is, first, the movable table 45 is lowered to the lowest position of the movable table guide portion 47, and the fuel 31 is placed on the movable table 45 by using the fuel exchanger. Next, the chain is wound by the chain winder 55, and the movable table 45 on which the fuel is placed is raised to the position of the shielding water depth 33. Thereafter, at this position, the channel box is gripped from above the fuel 31 using the fuel exchanger. In this state, next, the chain winder 55 is reversely rotated, the chain 53 is rewound to secure the movable base 45, and the channel box and the fuel bundle are separated.

When the fuel 31 is raised by the movable table 45 described above, the radiation dose monitoring device 36 operates. That is, when the fuel 31 reaches the position of the shield water depth 33, the limit switch 37 is turned on to stop the rise of the movable table 45. Alternatively, even when the movable table 45 is still below the set shield water depth 33, when the radiation dose from the fuel 31 reaches the expected radiation dose, the radiation dose detector 35 detects this radiation dose and detects the radiation dose. The device switch 38 is turned on, and the rise of the movable table 45 is stopped.

Therefore, also in the case of the other embodiments, as in the case of the above-mentioned embodiment, even if the limit switch 37 should fail, the radiation dose detector 35 can secure the shielding water depth and prevent the worker from being exposed. be able to. Further, when the radiation dose of the fuel 31 is higher than the assumed radiation dose, the radiation dose detector 35 is actuated to stop the rise of the fuel 31 even at a position below the shielding water depth 33. Can be reliably prevented.

〔The invention's effect〕

As described above, according to the nuclear power plant fuel handling facility according to the present invention, the shield water depth monitoring device is a detector that detects that the fuel supported by the fuel handling jig has risen to the preset shield water depth. And a radiation dose detector for detecting that the radiation dose from the fuel rising while being supported by the fuel handling jig reaches a predetermined value, and the fuel handling jig is operated by the operation of the detector and the radiation dose detector. Since it is configured to transmit the stop signal to the drive device, there is an effect that it is possible to reliably prevent the worker from being exposed to radiation when handling highly radioactive substances such as fuel.

[Brief description of drawings]

FIG. 1 is a side view showing an example of a nuclear power plant fuel handling facility according to the present invention applied to a fuel exchanger, and FIG.
FIG. 3 is a sequence diagram showing the configuration of a radiation dose monitoring device, third
FIG. 4 is a side view showing another embodiment of the nuclear power plant fuel handling equipment according to the present invention as applied to a fuel channel attachment / detachment machine, and FIG. 4 is a sequence diagram showing the configuration of a conventional shield water depth monitoring device. 11 …… Refueling machine, 13 …… Fuel pool, 21 …… Wire winder, 23 …… Fuel gripper, 31 …… Fuel, 33 …… Shielding water depth, 35 …… Radiation dose detector, 36 …… Shielding Water depth monitoring device,
37 …… Limit switch, 38 …… Radiation dose detector switch, 41 …… Fuel channel attaching / detaching machine, 45 …… Movable base, 55…
… Chain winder.

Claims (2)

[Claims] 1. A fuel handling jig which is provided so as to be movable in a vertical direction in a fuel pool and supports fuel at a tip portion, a fuel handling jig drive device for moving the fuel handling jig, and the above fuel handling. A detector that detects that the fuel supported by the jig has risen to a preset shielding water depth and that the radiation dose from the fuel that is supported and raised by the fuel handling jig has reached a predetermined value. A nuclear power plant fuel, comprising a radiation dose detector, and a shield water depth monitoring device for transmitting a stop signal to the fuel handling jig drive device by operating the detector and the radiation detector. Handling equipment. 2. A shielding water depth monitoring device has a limit switch installed in a fuel handling jig driving device and a radiation dose detector mounted on a workbench above the water surface of a fuel pool. When the fuel supported by the fuel handling jig rises to a preset shield water depth position, a stop signal is transmitted to the fuel handling jig driving device, and the radiation dose detector supports the fuel handling jig on the fuel handling jig. The nuclear power plant according to claim 1, wherein a stop signal is transmitted to the fuel handling jig driving device when the amount of radiation from the fuel rises to a predetermined value due to rising of the fuel. Fuel handling equipment.