Device and method for a rotary pressing positioning spring of a nuclear fuel rod

Abstract

The present invention belongs to the technical field of nuclear fuel element manufacturing, and particularly relates to a device and method for a rotary pressing and positioning spring of a nuclear fuel rod. This device is a variable-diameter positioning spring device. On the one hand, it meets the technical requirements for the precise positioning of the positioning spring within the cladding tube to ensure the assembly quality of the fuel rod. On the other hand, by designing a new positioning spring device, mass production of the product is achieved, and the production efficiency is improved.

Description

Technical Field

[0001] The invention belongs to the technical field of nuclear fuel element manufacturing, and in particular relates to a device and method for a nuclear fuel rod rotary pressure positioning spring. Background Art

[0002] The invention belongs to the field of manufacturing nuclear fuel elements for nuclear reactors, and specifically relates to an assembly device for producing nuclear fuel rods that meet product technical requirements and product acceptance outline requirements during the assembly process of nuclear fuel rods.

[0003] The existing fuel rod compression spring device needs to complete the following steps when compressing the spring: manually put the spring into the rotating disk → the probe rod compresses the core block → measure the origin → the probe rod withdraws → the rotating disk rotates → the probe rod pushes the spring → a dedicated person manually adjusts and inspects 100% of the time. The whole process is time-consuming and cumbersome. Moreover, when the "probe rod pushes the spring", due to the machining precision defects of the spring positioning rotating disk, the centering performance is not good. If the spring adding hole cannot be accurately controlled to the position of the axial center line of the compression spring device, it is very easy to push the spring or damage the fuel rod tube, or even push the probe rod against the spring adding hole, causing deformation and scrapping.

[0004] Abnormal operating deviations of the existing fuel rod compression spring device head will occur repeatedly, and the deformed and scrapped probe rods are expensive and costly due to high tolerance requirements and great processing difficulty.

[0005] The existing fuel rod compression spring device head push rod has no pressure relief valve, so pressure control is difficult to master. When the pressure is too high, it is very easy to crack the core block and produce debris inside the rod.

[0006] The existing fuel rod compression spring device head mechanism has no control software, and the operator cannot achieve real-time monitoring.

[0007] Fuel assemblies work for a long time in the reactor and are exposed to neutron radiation, high temperature and high pressure, as well as corrosion. Fuel rods are the most basic and core component of fuel assemblies. The quality of their assembly directly affects the quality stability of the assembly during transportation and the safety of its operation in the reactor.

[0008] When the nuclear fuel rod is assembled, its positioning spring is expanded within the specified size D in the cladding tube. In the prior art, the tooling is fixed at the beginning of the spring diameter change and directly pushed into the cladding tube, and the linear micrometer value is converted to position it in the cladding tube. The large diameter end has a pulling deformation to increase the spring wire spacing.

[0009] Due to the diameter of the spring wire, the effect of enlarging the spring wire spacing can be ignored on other products and the effect is very good. However, the effect is very poor when used for this product. The spring wire spacing is enlarged and occupies the position that should belong to the end plug, causing the end plug to not be pressed into place. Summary of the invention

[0010] The object of the present invention is to provide a device and method for a rotary pressing positioning spring of a nuclear fuel rod in view of the above-mentioned defects existing in the prior art. This device is a variable-diameter positioning spring device. On the one hand, it meets the technical requirements for accurately positioning the positioning spring inside the cladding tube to ensure the assembly quality of the fuel rod. On the other hand, by designing a new positioning spring device, mass production of the product is achieved, and the production efficiency is improved.

[0011] The technical solution of the present invention is as follows:

[0012] A device for a rotary pressing positioning spring of a nuclear fuel rod is provided with a knob at the left end of the device. One end of the knob is connected to a measuring probe rod, and the measuring probe rod extends uniformly to the positioning spring. A linear micrometer is provided on the right side of the end where the knob is connected to the measuring probe rod. The other end of the linear micrometer is connected to a cylinder, the other end of the cylinder is connected to a stepping motor, and the other end of the stepping motor is connected to a rotary pressing rod. A positioning block is provided on the measuring probe rod on the right side of the rotary pressing rod;

[0013] For a variable-diameter positioning spring, when being pressed in, the pressing rod rotates in the wire winding direction, exerting a contracting force on the large diameter of the positioning spring;

[0014] When the pressing is in place and the rotary pressing rod withdraws, the stepping motor rotates in the reverse direction, exerting a relaxing force on the large diameter of the positioning spring. Since the positioning spring rotates forward, the stretching of the large diameter section of the positioning spring is controlled, ensuring that the spring wire spacing of the large diameter section of the positioning spring is not affected.

[0015] When being pressed in, the pressing rod rotates 90° in the wire winding direction.

[0016] A method for a rotary pressing positioning spring of a nuclear fuel rod: For a fuel rod with components installed, the length of the artificial placement area of the positioning spring is pre-measured, and then the product is placed on the fixture with the product pipe orifice closely attached to the positioning block, and then the fixture is opened to clamp and position;

[0017] Start the cylinder for measuring the length of the placement area to drive the linear micrometer to move in a straight line. Through the measuring probe rod, the length value of the placement area of the positioning spring is rechecked. After the measurement is completed, the cylinder drives the linear micrometer and the measuring probe rod back to the original position, and the positioning spring is manually placed at the product pipe orifice through the positioning block;

[0018] Then start pressing the positioning spring. The cylinder drives the linear micrometer and the measuring probe rod to move in a straight line. At the same time, the stepping motor drives the rotary pressing rod to rotate in the set direction, and the positioning spring is screwed and pressed into the cladding tube. When the measuring probe rod is compressed to the set value, the stepping motor rotates the rotary pressing rod in the reverse direction, and the cylinder retracts, driving the linear micrometer and the measuring probe rod back to the original position. Finally, the fixture is opened, the product is taken out, rechecked, and the position of the positioning spring in the product is handed over to the next process.

[0019] The beneficial effects of the present invention are as follows:

[0020] This device has been applied to the mass production of fuel rods. The products are verified by X-ray radiography, and the qualified rate is 100%. The products are tested in the reactor and operate well. Description of the Drawings

[0021] Figure 1 It is a schematic diagram of the structure of the present invention;

[0022] In the figure: 1, linear micrometer; 2, stepping motor; 3, positioning block; 4, fixture; 5, product; 6, positioning spring; 7, measuring probe; 8, rotating pressure bar; 9, cylinder. Detailed Description of the Invention

[0023] The present invention will be further described in detail below with reference to the drawings and specific embodiments.

[0024] The rotary pressure positioning spring device for nuclear fuel rods is as Figure 1 shown. Its core part is the rotating pressure bar 8 and the rotating mechanism. A knob is provided at the left end of the device. One end of the knob is connected to the measuring probe 7, and the measuring probe extends uniformly to the positioning spring 6. A linear micrometer 1 is provided on the right side of the end where the knob is connected to the measuring probe 7. The other end of the linear micrometer 1 is connected to the cylinder 9, the other end of the cylinder 9 is connected to the stepping motor 2, the other end of the stepping motor 2 is connected to the rotating pressure bar 8, and a positioning block 3 is provided on the measuring probe 7 on the right side of the rotating pressure bar 8.

[0025] Based on the principle of self-tapping screws, a variable-diameter positioning spring 6 is like a self-tapping screw. When being pressed in, the pressure bar rotates in the wire winding direction (rotates 90°).

[0026] There is a force to contract the large diameter of the positioning spring 6. When the pressing is in place, when the rotating pressure bar 8 withdraws, the stepping motor 2 rotates in the reverse direction, and there is a force to relax the large diameter of the positioning spring 6. Since the positioning spring 6 rotates forward, the stretching of the large diameter section of the positioning spring 6 is controlled.

[0027] It ensures that the spring wire spacing of the large diameter section of the positioning spring 6 is not affected, and thus ensures the space that the end plug of the nuclear fuel rod should have. When used in cooperation with the linear micrometer 1, precise positioning is achieved.

[0028] The method for rotary pressure positioning of the spring is as follows:

[0029] For the fuel rod with components installed, the length of the artificial placement area of the positioning spring 6 is pre-measured, and then the product is placed on the fixture 4. The pipe orifice of the product 5 is closely attached to the positioning block 3, and then the fixture 4 is started to clamp and position, and the cylinder 9 for measuring the length of the placement area is started to drive the linear micrometer 1 to move in a straight line.

[0030] The length value of the placement area of the positioning spring 6 is rechecked by measuring the probe rod 7. After the measurement is completed, the air cylinder 9 drives the linear micrometer 1 and the probe rod 7 back to the original position, and the positioning spring 6 is manually placed at the pipe orifice of the product 5 through the positioning block.

[0031] Then start to press the positioning spring 6. The air cylinder 9 drives the linear micrometer 1 and the probe rod 7 to move in a straight line. At the same time, the stepping motor 2 drives the rotary pressing rod 8 to rotate in the set direction, and the positioning spring 6 is screwed and pressed into the cladding tube.

[0032] When the probe rod 7 is compressed to the set value, the stepping motor 2 rotates the rotary pressing rod 8 in the reverse direction, and the air cylinder 9 retracts, driving the linear micrometer 1 and the probe rod 7 back to the original position.

[0033] Finally, open the fixture 4, take out the product 5, recheck the position of the positioning spring 6 in the product 5, and hand it over to the next process.

Claims

1. A method for rotating a nuclear fuel rod and pressing a positioning spring, assembling the parts of the fuel rod, manually pre-measuring the length of the positioning spring placement area, and then placing the fuel rod on the fixture, with the fuel rod tube mouth close to the positioning block, Features: Then open the clamp to clamp and position, start the measurement of the placement area length, the cylinder drives the linear micrometer to do linear motion, and verifies the length value of the positioning spring placement area through the measuring probe. After the measurement is completed, the cylinder brings the linear micrometer and the measuring probe back to their original position, and the positioning spring is manually placed at the fuel rod tube mouth through the positioning block, and then starts to press the positioning spring, the cylinder drives the linear micrometer and the measuring probe to do linear motion, and at the same time the stepper motor drives the rotating pressure rod to rotate in the set direction, the positioning spring is screwed into the cladding tube, when the measuring probe is compressed to the set value, the stepper motor rotates the rotating pressure rod in the opposite direction, the cylinder retreats, driving the linear micrometer and the measuring probe back to their original position, and finally open the clamp, take out the fuel rod, verify the position of the positioning spring in the fuel rod, and hand it over to the next process.

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