A fuel assembly of a nuclear reactor

 

Used in construction aschehoug fuel assemblies, of which formed the active zone of water-water power reactors. A fuel Assembly includes guide channels having upper and lower pivot bushings. Upper bearing sleeve mounted for interaction with emphasis placed on the upper end of the guide channel. Emphasis is made in the form of a collet having a flange and United with him, clamping elements, on the outer surface of which is located the locking sleeve. Clamping elements collets are located in the annular groove made in the guiding channel. The technical result is to increase the reliability of the node stops, substantially increases the reuse of the fuel Assembly after disassembly, which increases the depth of the burn-up fuel, and also simplifies the Assembly and disassembly of the Assembly. 5 C.p. f-crystals, 6 ill.

The technical field to which the invention relates.

The invention relates to nuclear technology, in particular to designs aschehoug fuel assemblies, of which formed the active zone of water-water energy is based on the lower tip and upper tip, between which is located a beam guiding channels and fuel cells, fixed in the spacer grids (JP 2-22353, G 21 3/33, 04.06.1985). Top tip consists of a bottom transition plate and the upper presser plate, which is spring-loaded relative to the bundle of fuel elements and can slide along the guide channels. All the liners are United at the top attached to them by the stove. The liners are made from an alloy of zirconium, which swells under the action of neutron flux. Therefore, in the fuel Assembly, after standing some time in the active zone, the guide channels are extended. However, due to non-uniformity of neutron flux along the radius of the fuel Assembly and the inhomogeneity of the metal guide channels for the extension will be different. Obviously, over time the operation of the difference in elongation of the guide channels will increase, which may lead to distortion of the upper tip, and also to the curvature of the guide channels. As a result, significantly reduces the reliability of the fuel Assembly and the security of the active zone, as in the curved guide channels possible jamming installed in them regulisanja guide channels it is necessary to reduce the operation time of the fuel assemblies, consequently, the burnup of the fuel. Due to the fact that the upper tip is made permanent, damage to one or more fuel elements for reprocessing send the entire fuel Assembly.

Also known fuel Assembly of a nuclear reactor containing the bundle of fuel elements placed along the length of the fuel Assembly spacer grids, the shank and head, United the guide tubes, which are moved regulating rods (Improvements in Water Reactor Fuel Technology and Utilization, Proceedings of a symposium, Stockholm, 15-19 September 1986, IAEA, Vienna, 1987, p.183). The head in this fuel Assembly are removable. His transition plate is attached to the tops of the guide tubes by means of nuts that Contrada into the slots on the transition plate. This design allows to repair fuel Assembly - remove the nut, remove the head and replace the damaged fuel elements. This reduces the cost of the fuel cycle, because a fuel Assembly with minor injuries, containing enriched uranium cannot be removed prematurely from service. The disadvantage of this design is that all the guide tube is connected to agnosti fuel Assembly because of the possibility of curvature of the guide tubes and the security of the active zone of the nuclear reactor due to jamming control rods in a curved guide tubes, and also affects the economic performance of the fuel cycle, because it limits the depth of the burn-up fuel.

Known fuel Assembly, which has a removable top head is mounted on the guide tubes of zirconium alloy, and the tops of the pipes cut and function as springs (GB 2255669, G 21 3/32, 16.04.1992). When the protrusions on the guide tube is fixed in the holes in the plate head into the tube, insert the locking sleeve, which does not cut the parts of the top of the guide tube to be compressed. This design provides easy removal of the head, which is enough to pull the locking sleeve and removing the head from the guide tubes. In addition, the incisions in the upper part of the guide tubes function as damping devices, compensating the difference in the radiation growth tubes, resting in a common plate. However, such damping devices are negligible. In turn, the incisions in the upper part of the guide tubes weaken their mechanical strength, and a locking sleeve not thecontrary and can fly at an emergency situation associated with rupture of the output pipeline of the first circuit, when the differential pressure fuel Sona.

The closest in technical essence and the achieved result to the described invention is a fuel Assembly of a nuclear reactor containing rigidly connected to the shank of the guide channels, the upper part of which is accommodated in a spring unit including a bottom plate and top plate, each guide channel is located between the plates of the lower and upper bearing bushing, spring, respectively, to the lower plate and the upper plate, the upper support sleeve mounted for interaction with emphasis placed on the upper end of the guide channel above the upper plate (EN 2137223, G 21 3/32, 10.09.1999). In the known fuel Assembly emphasis is made in the form of a nut, the diameter of which is smaller than the diameter of the hole in the top plate. Spring mounted on the guide channels, not only hold the fuel Assembly from surfacing in the coolant flow, but also compensate for the uneven growth of the guide channels and align efforts from the refueling machine unloading a fuel Assembly from the core, while the springs in all cases work in compression. Thus, this design eliminates the curvature of the guide channels, motorcoach provides the use of a fuel Assembly after disassembly and replacement of defective fuel elements, because when loosening the nuts after her operation in conditions of exposure to radiation and elevated temperatures damaged and zakusyvaete her thread.

Therefore, when damage to the threaded connection between the nut and the guide channel for processing, you must submit the entire fuel Assembly, the resource is not selected.

The invention

The present invention is the development and creation of a fuel Assembly of a nuclear reactor, which has improved performance and enhanced economic performance.

The solution of this task is possible obtain a technical result consists in increasing the reliability of the node stops increasing significantly the re-use of the fuel Assembly after disassembly, which increases the depth of the burn-up fuel, as well as to simplify the Assembly-disassembly of the fuel Assembly.

These technical results are achieved by the fact that in the fuel Assembly of a nuclear reactor containing rigidly connected to the shank of the guide channels, the upper part of which is accommodated in a spring unit including a bottom plate and top plate, each napravlyu bottom plate and the top plate, moreover, the upper bearing sleeve mounted for interaction with emphasis placed on the upper end of the guide channel above the upper plate, each stop is made in the form of a collet having a flange and United with him, clamping elements, on the outer surface of which is located the locking sleeve, the locking elements collets are located in the annular groove made in the guiding channel and have a cross-sectional profile that corresponds to the cross-sectional profile of the annular groove, with the outer surface of the clamping elements are made in the flange to secure the locking sleeve from moving in the direction of the shank, and from moving in the opposite direction of the fixing sleeve is fixed by means of bent petals made on the flange of the collet.

A distinctive feature of the present invention is that each stop is made in the form of a collet having a flange and United with him, clamping elements, on the outer surface of which is located the locking sleeve, the locking elements collets are located in the annular groove made in the guiding channel, and have a cross sectional profile corresponding to the profile cross suit a bearing for the upper bearing sleeve. To secure the locking sleeve from moving in the direction of the shank on the outer surface of the clamping elements are made in the shoulder, and from moving in the opposite direction of the fixing sleeve is fixed by means of bent petals made on the flange of the collet. Thus, the fixed collet locking sleeve and the locking sleeve is fixed by means of the gripper elements-beads and petals.

In addition, the clamping elements are connected with the collar by means of jumpers made with the possibility of plastic deformation that allows you to install the collets to deflect the clamping elements to the desired position.

For easy removal of the locking sleeve on its outer surface may be made annular groove.

Preferably, the number of clamping elements and bent the petals were equal to 4.

Appropriate cross-sectional profile of the annular groove-side end of the guide channel to perform with a conical chamfer that will enable the deployment of the collet when it is dismantled with less effort.

List of figures

In Fig.1 shows a schematic diagram of the fuel Assembly of Fig.2 shows a section of a fragment of the spring unit, the cops stop during installation, in Fig.5 shows the final position of the elements of emphasis during Assembly of Fig.6 shows a case where the disclosure of the clamping gripper elements.

Information confirming the possibility of carrying out the invention

A fuel Assembly contains rigidly connected to the shank 1 guide channels 2 (conventionally one shown). The upper part of the guide channel 2 is placed in a spring block 3, whereby the head 4 has a possibility of disconnection with the guide channels 2 and the Central tube 5. A fuel Assembly for fixing and spacing of the bundle of fuel elements 6 (conventionally one shown). Fixation of the fuel elements is the spacer bars 7 (conventionally one shown). Spring unit 3 includes a bottom plate 8 and the upper plate 9. Each guide channel 2 is located between the plates 8 and 9 of the lower and upper bearing sleeve 10 and 11. The supporting sleeve 10 and 11 are biased by spring 12, respectively, to the base plate 8 and to the top plate 9. Upper bearing sleeve 11 is installed with the ability to interact with emphasis placed on the upper end of the guide channel 2 is above the upper plate 9. Every stop made in the form of collet 13 having Bua 16. Clamping elements 15 collets are located in the annular groove made in the guide channel 2, and have a cross-sectional profile that corresponds to the cross-sectional profile of the annular groove. On the outer surface of the clamping elements 15 is a flange 17 for fixing the locking sleeve from moving in the direction of the shank 1, and from moving in the opposite direction of the fixing sleeve is fixed by means of bent petals 18, made on the flange 14 of the collet. Clamping elements 15 is connected to the flange 14 of the collet by means of jumpers 19 made with the possibility of plastic deformation. On the outer surface of the locking sleeve 16 is made annular groove 20, which simplifies the operation of the gripping device, particularly when removing the retaining sleeve 16. The cross sectional profile of the annular groove made in the guiding channel 2 from the end of the guide channel is made with a conical chamfer, which simplifies the installation and disassembly of the elements.

Before you install the collets on conduit 2 clamping elements 15 are bent at an angle to the longitudinal axis of the gripper (see Fig.3) or parallel to the longitudinal axis of the collet by deformation of bridges 19. Then the collet ustanavlivatsya 16. Consequently, the clamping elements 15 are annular groove. After sending the locking sleeve 16 to produce the expanding lobes 18. In the collet securely mounted on guide rod. Removing the collet is produced by performing the above steps in reverse order.

The fabrication of this design can be implemented on any known equipment using standard technologies.

Claims

1. A fuel Assembly of a nuclear reactor containing rigidly connected to the shank of the guide channels, the upper part of which is accommodated in a spring unit including a bottom plate and top plate, each guide channel is located between the plates of the lower and upper bearing bushing, spring, respectively, to the lower plate and the upper plate, the upper support sleeve mounted for interaction with emphasis placed on the upper end of the guide channel above the upper plate, characterized in that each stop is made in the form of a collet having a flange and United with him, clamping elements, on the outer surface of which is located the locking sleeve, terminal e is AI profile, corresponding to the cross-sectional profile of the annular groove, with the outer surface of the clamping elements are made in the flange to secure the locking sleeve from moving in the direction of the shank, and from moving in the opposite direction of the fixing sleeve is fixed by means of bent petals made on the flange of the collet.

2. A fuel Assembly under item 1, characterized in that the clamping elements are connected with the collar by means of jumpers made with the possibility of plastic deformation.

3. A fuel Assembly under item 1 or 2, characterized in that on the outer surface of the locking sleeve is made annular groove.

4. A fuel Assembly under item 1, or 2, or 3, characterized in that the number of clamping elements is 4.

5. A fuel Assembly under item 1, or 2, or 3, or 4, characterized in that the number of bent petals equal to 4.

6. A fuel Assembly under item 1 or 2 or 3 or 4 or 5, characterized in that the cross sectional profile of the annular groove-side end of the guide channel is made with a conical chamfer.



 

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