JPH0634080B2 - Refueling machine with built-in control rod drive mechanism - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to a fuel exchanger with a control rod drive mechanism for driving control rods and exchanging fuel in a fast reactor.

(Prior Art) There are two types of fast reactors, a loop type and a tank type. In both types, the fuel exchanger is installed on the shield plug that closes the upper part of the reactor vessel to handle the fuel in the reactor vessel. Has been done.

An upper core mechanism that holds the control rod drive mechanism etc. is installed above the core.To exchange fuel in the reactor vessel, the upper core mechanism and the fuel exchange device are placed in a rotating plug to The rotating movement of the plug and the swiveling movement of the refueling device allow the refueling device to access all regions of the core.

In addition to the functions of lifting and lowering the gripper, grasping and releasing the fuel, the above fuel exchange device is equipped with a mechanism for holding down the surrounding fuel to prevent the surrounding fuel from rising when the fuel is withdrawn. The equipment of.

(Problems to be Solved by the Invention) As described above, in the conventional nuclear reactor, the fuel exchange device as a dedicated machine is provided on the shielding plug, and the structure is complicated, and the atomization is possible in terms of physical quantity and arrangement space. It had a large specific gravity in the furnace structure.

The present invention has been made in view of the above points, in order to simplify the reactor and fuel exchange equipment, the fuel exchange device that handles the fuel exchange is deleted, in addition to the control rods with the gripper of the control rod drive mechanism, An object of the present invention is to provide a fuel exchanger with a built-in control rod drive mechanism that enables handling of fuel and that also removes the hold-down device of the fuel exchange device by holding down the rotary plug by lifting and lowering the rotary plug. It is a thing.

[Structure of the Invention] (Means for Solving Problems) The present invention is installed in a core upper mechanism above a control rod, and grasps and releases the control rod, withdraws, scrums, and grasps and releases fuel. In a fuel exchange machine with a control rod drive mechanism equipped with insertion and extraction functions, this fuel exchange machine with a control rod drive mechanism has an inner fuel exchange device that handles only the inner region of the core and an outer fuel exchange that handles only the outer region of the core. And a device.

(Operation) In the control rod drive mechanism built-in fuel exchanger of the present invention configured as described above, the rotary plug lifting device installed for turning the rotary plug is used to hold down the surrounding fuel when extracting the fuel. Then, the fuel is transferred to the fuel inlet / outlet unit by the swiveling operation of the rotary plug. Furthermore, the fuel exchange unit handles only the inner region of the core and the outer region of the core. Can be eliminated, and the device arrangement on the shielding plug can be facilitated.

(Example) Next, the Example of this invention is described with reference to drawings.

FIG. 1 shows a structural example of a main part of a nuclear reactor structure to which the present invention is applied, in which a small rotation plug 3 and a large rotation plug 4 are provided above a reactor vessel 2 accommodating a core 1. 5 are installed, and a circulation pump 6 and a fuel exit / entry machine 7 are installed.
Etc. are installed. Further, a core rotating mechanism 8 for holding a control rod driving mechanism and the like is provided in the small rotating plug 3 located above the core 1 during power operation, and a fuel exchange device 9 also having a function of the control rod driving mechanism is provided therein. Is permanently installed.

FIG. 2 shows an example of the configuration of the above-described fuel exchange device 9. This fuel exchange device comprises a drive unit 10 and an upper guide tube 11, and a drive motor 12 is provided on the top of the drive unit 10.
Is connected to a drive shaft having a double pipe structure, and a ball nut 14 that vertically moves up and down by the rotation of the drive motor 12 is screwed onto the screw-shaped drive shaft outer side 13a. An electromagnet 15 is provided at the lower end of the ball nut 14. Reference numeral 13b indicates the inside of the drive shaft.

Further, the upper guide pipe 11 is provided with a stroke bellows 16 for preventing the in-furnace coolant from entering the drive unit 10, an inner extension pipe 18 provided with a latch bellows 17, and an outer extension pipe 19. Further, on the outside of the outer extension pipe 19, an acceleration pipe 21 is installed via an acceleration spring 20 arranged concentrically.

Further, a gripper opening / closing rod 22 is provided at the tip of the inner extension pipe 18.
Is provided and is connected via a connecting link 23 to a control rod 24 and a gripper 26 capable of gripping the fuel (lower guide pipe 25 in the case of a control rod). Further, a gripper opening / closing drive mechanism 28 for vertically moving a drop buffer portion 27 of the inner extension pipe 18 to which the gripper opening / closing rod 22 is connected is installed in the drive portion.

Next, the operation of the device of the present invention configured as described above will be described.

As shown in FIG. 3, during the output operation of the nuclear reactor, the top of the control rod 24 is grasped from the outside by the gripper 26, and the electromagnet 15 is excited by the upper portion of the inner extension pipe 18 to which the gripper opening / closing rod is connected. Thus, the state shown in this figure is maintained, and the stroke of the control rod is adjusted by the vertical movement of the outer extension tube 19.

On the other hand, during the scrum operation, when the control rod 24 is dropped, the electromagnet 15 is demagnetized and only the inner extension pipe 18 is dropped to the drop buffer portion 27, while the connection link 23 pushes the gripper 26 open, and The lower surface of the accelerating tube 21 surely pushes the top of the control rod 24.

Further, at the time of refueling, after the control rod 24 is cut off, the lower guide pipe 25 or the same handling head shape is used with the drop buffer 27 suspended and the gripper closed as shown in FIG. To grab the fuel
Lower the gripper to the core. After the gripper reaches the core top in this way, as shown in FIG. You can grab 30.

Further, when the fuel 30 is extracted, the fuel 30 can be extracted by raising the outer extension pipe 19 while preventing the gripper 26 from closing by lowering the drive shaft 13b. It should be noted that the reverse procedure may be taken when inserting the fuel 30.

Further, the lower guide tube 24 can be handled by the same procedure.

Then, as shown in FIG. 6, on the small rotary plug 3, two units, an inner fuel exchange device 9a and an outer fuel exchange device 9b, are installed. Here, the inner fuel exchange device 9a handles only the inner region of the core, and the outer fuel exchange device 9b
Shall deal only with the outer region of the core. When the fuel is transferred from the inner region of the core to the fuel inlet / outlet delivery position 31, the fuel in the core relay position 32 is extracted beforehand.
It suffices to transfer it from the inner fuel exchange device 9a to the outer fuel exchange device 9b using this as a relay point. At this time, the bending of the fuel to be handled can be dealt with by pulling out several fuels and the like around it in advance so as not to hinder the fuel insertion into the intra-core relay position 32.

When the rotary plugs 3 and 4 are swung, they are jacked up by a lifting device, but when the fuel is extracted from the core, if this is jacked down, the lower end of the core upper mechanism prevents the fuel around the extracted fuel from floating. It can be prevented.

When grasping the control rod 24 after the refueling is finished,
As shown in the figure, after the gripper 26 reaches the core top part, the drop buffer part 27 is lowered to once open the gripper 27 via the communication link 23. Further, when the outer extension pipe 19 is lowered and the drop buffer portion 27 is lifted, the top of the control rod 24 can be gripped by the gripper 26.

In the above embodiment, an example in which the control rod is grasped by closing the gripper inside and the fuel is grasped by opening it outside is explained as an example, but the present invention is not limited to this, and other grasping methods are also possible. The same applies.

[Effects of the Invention] As described above, according to the present invention, it is possible to eliminate the fuel exchange device that only performs the fuel exchange, and further to provide the fuel exchange machine having the control rod drive mechanism function only in the inner region of the core. By dividing into those with the function of handling and those with the function of handling only the outer region of the core, the horizontal movement range of the exchange can be reduced, and in addition, a small rotation plug,
Since the diameters of the large rotation plug and the core can be reduced, the equipment can be reduced and simplified.

Further, normally, since the refueling device is installed only at the time of refueling, this preparatory work requires time, but according to the present invention, refueling can be performed immediately after the reactor is stopped, and the operating rate is improved. In addition, the load on the shield plug can be eliminated, and the design becomes easier.

[Brief description of drawings]

FIG. 1 is a schematic view of a main part of a nuclear reactor showing an application example of the present invention,
FIG. 2 is an overall view of the fuel exchanger of the present invention, and FIGS.
FIG. 7 and FIG. 7 are operation explanatory views of the fuel exchanger of the present invention, and FIG. 6 is a plan view of a nuclear reactor to which the present invention is applied. 1 ... Reactor 2 ... Reactor Vessel 3 ... Small Rotation Plug 4 ... Large Rotation Plug 5 ... Shielding Plug 6 ... Circulation Pump 7 ... Fuel In / Out 8 ... Reactor Upper Mechanism 9 ... Fuel Exchanger 9a …… Inside fuel exchange device 9b …… Outside fuel exchange device 10 …… Driving part 11 …… Upper guide tube 12 …… Driving motor 13a …… Driving shaft outside 13b …… Driving shaft inside 14 …… Ball nut 15 …… Electromagnet 16 …… Stoke bellows 17 …… Latch bellows 18 …… Inner extension tube 19 …… Outer extension tube 20 …… Acceleration spring 21 …… Acceleration tube 22 …… Gripper opening / closing rod 23 …… Connection link 24 …… Control rod 25… ... Lower guide tube 26 ... Gripper 27 ... Drop buffer 28 ... Gripper opening and closing drive unit 30 ... Fuel 31 ... Fuel entry and exit unit delivery position

Claims (1)

[Claims] 1. A core upper mechanism installed above a control rod,
In a fuel exchange machine with a control rod drive mechanism having control rod gripping and releasing, withdrawing and scrum functions, and fuel grasping and releasing, insertion and withdrawal functions, the control rod driving mechanism incorporated fuel exchange device is provided in the inner region of the core. A refueling machine with a control rod drive mechanism, comprising an inner refueling device that handles only the outer refueling device that handles only the outer region of the core.