JPH075288A - Reactor refueling machine - Google Patents

Abstract

PURPOSE:To shorten the reactor outage period for refueling. CONSTITUTION:At the upper part of a reactor vessel 2, a guide cylinder 4 and a fuel insertion and withdrawal device 5 is fixed and a refueling machine 10 is fixed in the guide cylinder 4. The refueling machine 10 is provided with a relay mechanism 11 to hold a pot 12, a gripper mechanism 13 to grasp a fuel assembly 3, a winder 14 to hung up the gripper mechanism with a wire rope 17, art arm 15 to move the gripper mechanism 13 to the core radius direction by moving the wire rope 17 and a rotation device to rotate the whole device and move the gripper mechanism 13 to the core circumferential direction. A spent fuel assembly 3 is contained in the pot 12 and taken out of the reactor in this state.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a fuel exchange device for a nuclear reactor, and more particularly to a nuclear reactor fuel exchange device suitable for a small reactor.

[0002]

2. Description of the Related Art Generally, in a small-sized nuclear reactor, since the space around the core is limited and a place for replacing a fuel assembly with a pot cannot be provided, a method of directly taking out bare fuel is adopted. .

FIG. 6 shows a conventional small-sized nuclear reactor which adopts a method of directly removing the reactor fuel directly.
Reference numeral 1 is a reactor building, a reactor vessel 2 is provided in the reactor building 1, and a plurality of fuel assemblies 3 are installed under the reactor vessel 2.

At the time of refueling, the guide tube 4 is installed on the upper part of the nuclear reactor, and the fuel inlet / outlet device 5 is installed thereon.
Then, the gripper 6 is suspended from the fuel inlet / outlet device 5 via the wire rope 7, and the spent fuel assembly 3 is directly used.
Is grasped and suspended in the fuel inlet / outlet device 5 to be moved.

[0005]

In the conventional fuel exchange device, the bare fuel is stored in the gas in the fuel inlet / outlet device 5 and transferred, but the heat removal amount of the gas is limited.
It is necessary to lower the calorific value of the fuel to a sufficiently low value before handling it due to the restriction conditions of the fuel cladding temperature. This is because the fuel assembly 3 accommodates and holds a large number of small-diameter fuel pins therein, and has a low heat transfer performance in the gas, and the temperature of the pin in the central portion easily rises. Because.

In the conventional nuclear reactor refueling apparatus, it is usually necessary to wait several months for the decay time of the fuel heat generation after the nuclear reactor is shut down, so that the period for shutting down the nuclear reactor for refueling becomes long and it is operated. There is a problem that the rate decreases.

[0007] In order to shorten the reactor shutdown period for refueling, it is preferable that the reactor be placed in a sodium pot having good thermal conductivity and transferred, but for that purpose, the pot and the core are arranged in a reactor with a small space. A reactor refueling device that can transfer fuel to and from it is required.

The present invention has been made in consideration of the above-mentioned circumstances, and provides a reactor fuel exchange device capable of easily transferring fuel between a pot and a core in a reactor having a small space. The purpose is to

[0009]

As a means for achieving the above object, the present invention provides a fuel refueling system in which a fuel inlet / outlet device is mounted above a reactor pressure vessel via a guide cylinder to perform fuel refueling. In the device, a relay mechanism for holding the pot suspended from the fuel inlet / outlet device in the liquid in the upper part of the core, and a gripper mechanism for suspending the gripper via a wire rope to grip and separate the fuel assembly and move up and down. , A radial movement mechanism that moves the wire rope of the gripper mechanism in the radial direction to move the gripper in the radial direction, and the radial movement mechanism and the relay mechanism are attached to rotate the gripper mechanism in the horizontal direction to move the gripper in the circumferential direction. And a rotating device for performing the rotation.

Further, in the present invention, it is preferable to use the fuel inlet / outlet device as the gripper mechanism and the guide of the gripper suspending device as the radial movement mechanism.

[0011]

In the reactor refueling system according to the present invention,
By moving the position of the gripper using the radial movement mechanism and the rotating device, the fuel can be handled between the arbitrary core position and the pot, and this handling work can be performed in the reactor. It will be possible.

Further, in the present invention, by using the fuel inlet / outlet device as the gripper mechanism and using the guide of the gripper suspending device as the radial movement mechanism, the structure of the device can be simplified.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to the drawings.

FIG. 1 shows a reactor fuel exchange apparatus according to a first embodiment of the present invention. In the drawing, reference numeral 1 is a reactor building, and inside this reactor building 1 is a reactor vessel 2 Is provided, and a plurality of fuel assemblies 3 are installed in the lower part. At the time of refueling, the guide tube 4 is installed on the upper part of the reactor, the fuel inlet / outlet device 5 is installed on the guide tube 4, and the fuel exchange device 10 is assembled in the guide tube 4.

As shown in FIGS. 1 to 4, the fuel exchange device 10 includes a pot 12 suspended from a fuel inlet / outlet device 5.
The relay mechanism 11 for guiding and holding the
Gripper mechanism 1 for handling the fuel assembly 3 between the core and the core
3, a hoisting machine 14, an arm 15, and a rotating device 16.

The gripper mechanism 13 is suspended by two wire ropes 17, and each of the wire ropes 17 is wound around two drums of the hoisting machine 14. The gripping and releasing operation of the gripper mechanism 13 is performed by the differential of the two wire ropes 17, and the vertical movement of the gripper mechanism 13 is performed by the synchronous winding and rewinding of the wire rope 17 by the drum. ing.

As shown in FIG. 2, the arm 15 has an intermediate portion in the vertical direction pivotally attached to the inner surface of the fuel exchange device 10 via a support shaft 18, and a lower end portion thereof swings in the radial direction of the core. A pulley 19 for guiding the wire rope 17 is provided at the lower end of the arm 15. By swinging the arm 15, the gripper mechanism 13 can be moved in the radial direction of the core.

Further, as shown in FIG. 2, the rotating device 16 is arranged at the lower end of the guide tube 4, and the refueling device 10 is provided.
The whole is rotated in the horizontal direction around the core axis, and by the rotation by the rotating device 16, the gripper mechanism 13 can be moved in the core circumferential direction.

Next, the operation of this embodiment will be described.

When exchanging fuel, first, the fuel inlet / outlet device 5
Then, the pot 12 is hung down and held by the relay mechanism 11.
Next, the hoisting machine 14 is operated to lower the gripper mechanism 13, and the arm 15 and the rotating device 16 are operated to move the gripper mechanism 13 to an arbitrary core position. Then, the spent fuel assembly 3 is transferred to the gripper mechanism 1
Grab 3

Next, the hoisting machine 14 is operated to raise the gripper mechanism 13, and the arm 15 is operated to move the gripper mechanism 13 in the core radial direction, so that the fuel assembly 3 gripped by the gripper mechanism 13 is moved. Store in pot 12.

By the way, the reactor vessel 2 of the small reactor is
When the spent fuel is stored in the pot 12 held by the relay mechanism 11, the high heat generation portion of the fuel assembly 3 has a vertically elongated structure and the height below the liquid surface above the core is sufficiently long. Is carried out under the liquid surface, and thereafter, after that, it is transferred to the outside of the furnace in a state where cooling is ensured by sodium in the pot 12. Therefore, the heat removal capacity of the fuel assembly 3 is greatly improved as compared with the conventional transfer in gas, and the temperature of the fuel can be suppressed to a lower level to improve safety.

Further, since the heat removal capacity is improved, conventionally, after the reactor is shut down, the damping waiting time for reducing the heat generation amount until the fuel assemblies 3 can be taken out and transferred takes a very long time of several months or more. However, this waiting time is almost unnecessary, and the period for shutting down the reactor for refueling can be greatly shortened.

FIG. 5 shows a second embodiment of the present invention, in which the fuel assembly 3 is transferred using the fuel inlet / outlet device 5 to simplify the device.

That is, the gripper mechanism 6 of the fuel inlet / outlet device 5 has a two-stage claw, and the pot 12 and the fuel assembly 3 are connected.
The gripper mechanism 6 is moved in the core radial direction by moving the wire rope 7 by means of the wire rope guide 21 in the positioning device 20. The movement of the gripper mechanism 6 in the circumferential direction of the core is performed by the rotating device 16 as in the first embodiment.

In other respects, the construction is the same as that of the first embodiment and the operation is the same.

Since the fuel assembly 3 is gripped and separated by the fuel inlet / outlet device 5 and stored in the pot 12, the structure of the device can be simplified.

[0028]

As described above, according to the present invention, the pot is arranged in the liquid above the core, the spent fuel is stored in the pot, and the fuel is transferred while being stored in the pot. , The heat removal capacity of the fuel assembly is greatly improved compared to the conventional transfer in gas, the temperature of the fuel can be kept lower to improve safety, and the reactor is shut down for fuel exchange. It is possible to significantly shorten the period for doing.

Further, in the present invention, by using the fuel inlet / outlet device as the gripper mechanism and the guide of the gripper suspending device as the radial movement mechanism, the device structure can be further simplified.

[Brief description of drawings]

FIG. 1 is an overall configuration diagram showing a first embodiment of a reactor fuel exchange device according to the present invention.

FIG. 2 is an enlarged view of a main part of FIG.

FIG. 3 is a plan view of FIG.

FIG. 4 is a sectional view taken along line IV-IV in FIG.

FIG. 5 is an overall configuration diagram showing a second embodiment of a nuclear reactor fuel exchange system according to the present invention.

FIG. 6 is an overall configuration diagram showing a conventional nuclear reactor refueling device.

[Explanation of symbols]

 2 Reactor Building 3 Fuel Assembly 4 Guide Tube 5 Fuel In / Out Device 6,13 Gripper Mechanism 7,17 Wire Rope 10 Fuel Exchanger 11 Relay Mechanism 12 Pot 14 Hoisting Machine 15 Arm 16 Rotating Device 19 Pulley 20 Positioning Device 21 Wire Rope guide

Claims (2)

[Claims] 1. In a nuclear reactor fuel exchange apparatus for mounting a fuel inlet / outlet device above a reactor pressure vessel via a guide tube to exchange fuel, a pot suspended from the fuel inlet / outlet device is located above the core. Relay mechanism to hold in the liquid of
A gripper mechanism that hangs the gripper via a wire rope to grip and separate the fuel assembly and move up and down, and a radial movement mechanism that moves the wire rope of the gripper mechanism in the radial direction to move the gripper in the radial direction. A nuclear fuel refueling device comprising: the radial movement mechanism and a rotation device to which the relay mechanism is attached and which rotates in a horizontal direction to move a gripper in a circumferential direction. 2. The nuclear fuel refueling apparatus according to claim 1, wherein a fuel inlet / outlet device is used as the gripper mechanism, and a guide of a gripper suspension is used as the radial movement mechanism.