CN102142287B - A fuel assembly underwater turning mechanism - Google Patents

Abstract

The invention discloses an underwater turning mechanism for a fuel assembly, which includes an annular baffle, a driving rod, a sleeve, an end cover, a ratchet, a pawl, a check pawl, a bracket, a pull rod, a positioning pin, a positioning shaft, and an annular baffle. Fixed on the bracket, the sleeve and ratchet are installed on the bracket through the positioning shaft, and the axis of the annular baffle coincides with the axis of the ratchet. The upper end of the vertical hole of the positioning shaft is provided with a guide sleeve, and the positioning pin can be along the guide The sleeve falls into the vertical hole of the positioning shaft, the positioning pin is connected to the pull rod, end caps are installed at both ends of the sleeve, and the driving rod is connected to the pawl. The invention provides an underwater turning mechanism for a fuel assembly that has a simple structure, is easy to install, has reliable action, has deep water body for turning, and meets space requirements.

Description

A fuel assembly underwater turning mechanism

technical field

The invention relates to the technical field of nuclear reactor engineering, in particular to an underwater turning mechanism for a fuel assembly.

Background technique

During the decommissioning process of the heavy water research reactor, the fuel assembly needs to be turned over in a certain underwater space, which requires a reliable operation process and is conducive to the radiation protection of the operator. At present, there is no precedent for the decommissioning of heavy water research reactors in China, and the fuel assemblies of pressurized water reactors are completely different from those of heavy water research reactors. The existing turning mechanism cannot meet the processing process of radioactive fuel assemblies.

Contents of the invention

The invention overcomes the deficiencies in the prior art, and provides a fuel assembly underwater turning mechanism with simple structure, convenient installation, reliable action, deep turning water body and meeting space requirements.

In order to solve the above technical problems, the present invention is achieved through the following technical solutions:

A fuel assembly underwater turning mechanism, including an annular baffle, a drive rod, a sleeve, an end cap, a ratchet, a pawl, a non-return pawl, a bracket, a pull rod, a positioning pin, and a positioning shaft. The key is that the annular baffle is fixed On the bracket, the sleeve and the ratchet are installed on the bracket through the positioning shaft, and the axis of the annular baffle coincides with the axis of the ratchet. A guide sleeve is arranged directly above the vertical hole of the positioning shaft, and the positioning pin can be moved along the guide sleeve. The tube falls into the vertical hole of the positioning shaft, the positioning pin is connected to the pull rod, the two ends of the sleeve are equipped with end caps, and the driving rod is connected to the pawl.

The present invention can also:

Rollers are installed on the end cap, which reduces the friction between the end cap and the annular baffle, and makes the sleeve slide on the annular baffle more easily. A counterweight is installed on the end cover. Counterweight is housed on the described ratchet.

Compared with prior art, the beneficial effect of the present invention is:

In the present invention, through the cooperation of the sleeve and the annular baffle, under the action of the driving rod, the sleeve rotates along the annular baffle, thereby completing the rotation of the fuel assembly. The device has a simple structure and can be operated from a long distance, and through the cooperation of the positioning pin and the positioning shaft, the requirement of the rotation position is well met, and the operation is safer and more reliable.

Description of drawings

Figure 1 Schematic diagram of the device

Figure 2 A view as shown in Figure 1

Figure 3 is a partial enlarged view of I shown in Figure 1

In the figure, 1 end cover, 2 sleeve, 3 non-return pawl, 4 ratchet, 5 bracket, 6 annular baffle, 7 pull rod, 8 guide sleeve, 9 positioning shaft, 10 driving rod, 11 positioning pin, 12 pawl , 13 rollers

Detailed ways

Below in conjunction with accompanying drawing and specific embodiment the present invention is described in further detail:

A fuel assembly underwater turning mechanism, as shown in Fig. Support 5, pull rod 7, positioning pin 11, positioning shaft 9 are formed, sleeve 2 and ratchet 4 are installed on the support 5 by positioning shaft 9, sleeve 2 and ratchet 4 are fixed together and can rotate around positioning shaft 9 synchronously. The annular baffle 6 with the upper opening is fixed on the bracket 5, and the axis of the annular baffle 6 coincides with the axis of the ratchet 4, that is, the annular baffle 6 and the ratchet 4 are coaxial, so that the end cap connected to the sleeve 2 can be guaranteed 1 always keeps the same distance from the ring baffle 6 during the rotation. The positioning shaft 9 is provided with a vertical hole, and a guide sleeve 8 is arranged directly above the vertical hole. The positioning pin 11 can fall into the vertical hole of the positioning shaft 9 along the guide sleeve 8 in the guide sleeve 8 to realize positioning. Locking of axis 9. The positioning pin 11 is connected on the pull rod 7 , and the positioning pin 11 can be pulled out from the vertical hole of the positioning shaft 9 by applying a pulling force on the pull rod 7 .

Both ends of the sleeve 2 are equipped with end caps 1 , and in this embodiment, rollers 13 are preferably installed on the end caps 1 , so that the friction between the end caps 1 and the annular baffle 6 can be reduced. The driving rod 10 is connected with the ratchet 12, and the ratchet 12 drives the ratchet 4 to rotate in one direction. In order to better prevent the ratchet 4 from rotating in reverse, a non-return pawl 3 is installed on the ratchet 4, and the non-return pawl 3 is on the side of the ratchet 4. Slide on the back of the tooth. When the ratchet 4 reversely rotates, the non-return pawl 3 prevents the ratchet 4 from reversely rotating.

When the end cap 1 of the sleeve 2 rotates to the opening of the annular baffle 6, in order to automatically open the end cap 1 by the self-weight of the end cap 1, the present invention preferably adopts adding a counterweight at one end of the end cap 1. Similarly, a counterweight is added to one end of the ratchet 12 so that the ratchet 12 is always in the meshing state with the ratchet 4 to realize continuous driving of the ratchet 4 .

Action process of the present invention is as follows:

Before the device is rotated, put the fuel assembly into the sleeve 2 with a special gripper for fuel assemblies, pull the pull rod 7 to move the positioning pin 11 upwards out of the vertical hole of the positioning shaft 9, and release the locking of the positioning pin 11 and the positioning shaft 9. The ratchet 4 is driven to rotate through the ratchet 12 connected to the lower end of the drive rod 10 , thereby driving the sleeve 2 to rotate clockwise around the center. When the end cover 1 enters the annular baffle 6, the fuel assembly is sealed into the sleeve 2, and the non-return pawl 3 prevents the ratchet 4 from reversing.

When the sleeve 2 turns 180 degrees, the positioning pin 11 automatically falls into the vertical hole of the positioning shaft 9 in the guide sleeve 8 by gravity to realize locking, and at this time the other end cover 1 of the sleeve 2 slides out of the annular baffle 6 , and is automatically opened under the action of gravity moment to realize the purpose of turning over the fuel assembly, and the fuel assembly can be taken out from the sleeve 2 again by using the special gripper for the fuel assembly.

Claims (4)

1. A fuel assembly underwater turning mechanism, comprising an annular baffle, a drive rod, a sleeve, an end cap, a ratchet, a pawl, a non-return pawl, a bracket, a pull rod, a positioning pin, and a positioning shaft, and is characterized in that the annular The baffle is fixed on the bracket, the sleeve and the ratchet are installed on the bracket through the positioning shaft, and the axis of the annular baffle coincides with the axis of the ratchet. A guide sleeve is arranged at the upper end of the vertical hole of the positioning shaft. The guide sleeve falls into the vertical hole of the positioning shaft, the positioning pin is connected on the pull rod, end caps are installed at both ends of the sleeve, and the driving rod is connected with the ratchet. 2 . The fuel assembly underwater turning mechanism according to claim 1 , wherein rollers are installed on the end cover. 3 . 3. The underwater fuel assembly turning mechanism according to claim 1, wherein a counterweight is installed on the end cover. 4. The fuel assembly underwater turning mechanism according to claim 1, wherein a counterweight is mounted on the pawl.

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