CS656590A3 - Fuel element of a nuclear reactor and process for producing thereof - Google Patents

Description

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BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a nuclear reactor fuel cell with parallel bars, in particular nuclear fuel-containing rods, which are connected by spacers and used in pressurized, boiling and fruiting reactors. The invention is of particular importance for the expansion of fuel rods in modern pressurized water reactors, which have a small distance between fuel rods compared to conventional pressurized water reactors. The invention also relates to a method for producing a spacer for a nuclear reactor fuel cell. A nuclear reactor is known in which the spacers assembled from the mesh meshes are arranged to accommodate each individual rod. Spacers are assembled from sleeves. A quadratic spacer sleeve is placed in each lattice between two octagonal sleeves. In this case, the half sleeves of the spacer sleeves are formed on the main sleeves so that, when the lattice spacer is assembled, the free ends of the legs of the sleeve halves of one sleeve and the free ends of the sleeve half halves of the adjacent main sleeve abut. Their contact points are welded and form longitudinal seams that have little resistance to flow through the fuel cell flowing through. In modern pressurized reactors, it has great difficulty in maintaining the spacing between the fuel rods due to the fact that their distance is much smaller than conventional pressure reactors. It is an object of the present invention to provide a nuclear reactor with a spacer and to provide a method for producing a spacer so that, even at low rod distances, the rods can be reliably held in position relative to each other and as low as possible. SUMMARY OF THE INVENTION The present invention provides a nuclear reactor fuel cell with parallel bars, in particular rods containing nuclear fuel, and a spacer forming a prismatic sleeve, the meshes of which serve to insert individual rods, the sleeve being bent over a web whose loose ends in the assembled receptacles on they are abutting each other and forming portions of the walls of the other objects, the contact points being joined by welding or soldering.

This construction allows for a tight mesh arrangement while not reducing the flow cross section by overlapping or doubling the bonded walls in the spacer eyes. Spacer sleeves can be manufactured with a single piece of sheet metal on vending machines with great precision, while the spacing of the spacer grille can be precisely maintained with suitable mounting and welding equipment.

For using pal. In a modern pressurized water reactor, it is expedient for the sleeves to have the shape of a hexagonal prism and to be wetted from the corners of the sleeves. In contrast to the spacer, where octagonal main sleeves and quadratic spacers are used, this design achieves a substantial simplification and reduction of the flow resistance of the coolant, since the spacer sleeves are eliminated, - preferably the uprights are inclined at their angled ends. It allows the use of very thin plates for sleeves without the need to duplicate or overlap the plates to create a durable weld seam.

In order to minimize the flow resistance of the coolant, it is expedient, according to the invention, to cut out at least one parallel-shaped cut-out in at least one wall and avoid the lamella formed therebetween, thus forming a spring which serves 1? backlash-free mounting for rods in sleeve.

The invention also relates to a method for producing a 'spacer' for a fuel cell of a nuclear reactor with parallel bars, in particular fuel-containing rods. In this process, the expanded sleeve casing is punched out of the metal sheet, which is provided with notches for the uprights and parallel slots to form the lamellae and notches, then it is molded into a prismatic sleeve and the point of contact formed by the jacket is welded or soldered. the webs and the lamellae, and the plurality of collars are mutually assembled in the spacer so that the free ends of the webs abut each other and form partitions of the additional sleeves, the webs being welded together or non-bonded to form a lattice whose mesh serves each to insert one rod . This method can be realized in a simple way, but mainly by cutting and bending machines.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a view of a nuclear reactor fuel cell, FIG. 3 is a plan view of a spacer, FIG. 5 is an enlarged plan view of a sleeve, FIG. 5 is a side view of the sleeve of FIG.

FIG. 1 depicts a fuel cell 1 which comprises fuel rods 6 in a six-sided grid arrangement, a predetermined number of mutually identical fuel cells disposed in a pressure vessel in the core reactor in its core, and flowing in the direction of arrow K bottom up refrigerant. Fuel cell fuel rods 7 are retained in a support assembly consisting of a fuel cell head 6 and a fuel cell 1 and a conduit that lies between the threads and into which the control rods shown are inserted. Spacers 6 ~ 1Λ are fastened to the guide tubes 6, which connect the fuel rods to a bundle and hold them so that they can expand freely, thereby leaving the coolant flow cross section open. uniform heating.

FIG. 2 shows a plan view of a portion of a hexagonal spacer 11 which forms a lattice by assembling prismatic sleeves 12. It serves to insert one fuel rod 2 ~.

As can be seen from FIG. 3, each of the sleeves 12 are bent over the walls 3 which form the wall portions of adjacent sleeves 14, the sleeve assemblies 12 abutting the free ends 13a of the upright. The points of contact 14 are welded together, the webs 14 are tapered at their free ends, which facilitates welding of the thin webs 13. In the manufacture of the sleeve, the expanded casing of the sleeve 12 is cut or punched out of the sheet, e.g. (Fig. 4). In doing so, they simultaneously cut or cut the notches Iq to form the upright 13, and the parallel cuts 5, 6, between which the lamellae form, are bent outwards between the parallel cut-outs 5, 6, thereby forming a spring I which provides a resilient fit for play. By passing the spring 17 from the sheet-forming sheath, the desired soft characteristic is achieved without additional elastic element being inserted into the sleeve 12. After cutting out or simultaneously with cutting out, the notches 1 can be displaced in the shell housing 1, which then serve as bearing elements for the fuel rod 2 housed in the sleeve,

The cut sheet metal 18 is shaped by the field into a prismatic sleeve 12, as shown in FIG. 5. The sides of the sleeve 12 are then welded or bonded. Before or after the connection, avoid the webs I3 and the slats from the sleeve h, then the sleeve becomes cloudy.

For each bar to be accommodated in the sleeve 12, at least a three-point bearing is formed in the housing 12, which comprises at least two indentations 20 and one spring 17. As shown in FIGS. Suitably, the sheet metal part 18 has on the contact sides of the evil, the slot 21 which engages the metal plate 23 on the opposite contact side 21a, 16b when forming the sleeve, thereby forming a forming engagement. 6-11, a predetermined number of Iz is connected to the grid. In this case, the walls 13 of the adjacent sleeves 2 form walls of the new sleeves. As shown, for example, in Fig. 2, by assembling the sleeves 12, 12a, 12b a new sleeve can be formed of 13 to three of the three sleeves 12, 12, 12b. Similarly, it repeats the other sockets. For the spacer eyes, which are on the edge, the longer sleeves Izd with open walls are welded to the Ha frame.

Claims (5)

uí-c-s · .--- ... ,,. ^ ........ ... ........., ........... ...... ... fl / íSí ^ Oli • -ligdl PATENT REQUIREMENTS fgóv "NXAOadl -_______. ..VSO 1, a nuclear reactor fuel cell with rods, in particular rods having a nuclear reactor and a nozzle, can be used to insert individual rods. rods, added from sleeves 1 5 6.5 6 S υ. the webs (13) are bent, the free ends of which (in the assembled sleeves (12) abut against one another and form the strip), the contact points (14) being joined by welding or soldering , 2. The fuel element according to claim 1, characterized in that the sleeve (I2) is in the form of a hexagonal prism and the web (13) is bent out of the clamp edges (I2). 3. A fuel cell according to claim 2, characterized in that the stand (11) is precipitated at the free ends (13a). 4. The fuel cell according to claim 1, characterized in that two parallel cuts (I5, 16) are cut out in at least one wall of the sleeve (I2) and the slat formed therebetween is bent to form a spring (I7) to receive the rod guided by the sleeve ( I2) without will, 5. A fuel cell according to claim 1 or 4, characterized in that at least one groove (20) is formed as a bearing for the rod (2) in the two walls of the sleeve (12). parallel bars, in particular bars containing fuels, in which a sheet of "sleeve (1z)" is cut out or punched out of the sheet, provided with notches (1 ">) for webs (I3) ς and parallel cutouts 15, 16) to form lamellae and notches (20 ), the sheet-metal sheet (18) forming at the granular sleeve, and its interfaces welded or soldered, then the screeds (I3) and lamellae and the predetermined number of sleeves (I2) are assembled in the spacer (6) so that the free ends (13a) the trunk (I3) abut against each other and form part of the walls of the additional sleeves (Izd), the webs (I3) being joined by welding or brazing to form a lattice whose mesh serves each for one rod {2).