CS201253B1 - Supporting structure for supporting and keeping the mutual distance of the fuel elements in the active zone of the water-hydraulic nuclear reactor - Google Patents

Description

BACKGROUND OF THE INVENTION The present invention relates to a support structure for supporting and maintaining the distance between fuel elements in the core of a water-water nuclear reactor, including a drum, to whose punched bottom the lower ends of the support elements are attached to the fuel elements and fuel element spacers.

The support structure according to the invention can be used in high-capacity water-water nuclear reactors.

At present, the main developmental tendency of nuclear power engineering is to increase the performance of nuclear reactors and to increase their technical and economic parameters, with special attention being paid to operational safety and production costs of the main reactor components.

The most promising direction to increase the operational safety and reliability of nuclear reactors is to increase their strength and improve the hydraulic characteristics.

Support structures are known for securing and maintaining the spacing of fuel elements in the core of nuclear reactors having a base member formed by two rigidly connected plates. The feet of the cells of the fissile material pass through the openings in the lower and upper plates, so that their exact position as well as the necessary spacing between them is ensured. The fuel cell feet rest on their own weight and rest on the bottom plate.

The fuel cell feet or shanks are hollow and have side openings for supplying the heat carrier to the fuel cells.

In these known support structures, the length of the fuel cells must be equal to the spacing between the two plates, which increases the overall length of the fuel cells and hence the necessary dimensions of the handling equipment and the external dimensions of the reactor building.

In addition, in these known designs, the plates that hold the fuel elements are flat and must therefore be made sufficiently thick to have sufficient strength and rigidity, and special equipment is necessary to process such plates, which substantially increases the manufacturing cost of the structure.

Another known support structure for supporting and maintaining the mutual spacing of fuel elements in the core of a nuclear reactor, as described in U.S. Pat. No. 3,486,973, comprises a drum in which the bottom ends of the support elements are fastened over the perforated bottom bottom. fuel cells and fuel cell spacers by which the heat transfer medium is supplied to the fuel cells.

The spacers are formed by two plates provided with a plurality of apertures for the passage of the heat transfer fluid to the fuel elements and to hold the upper ends of the support elements and the fuel elements at prescribed distances therebetween.

When this support structure is used in a water-water nuclear reactor, the number of support elements is insufficient to provide the necessary strength and operational reliability of the entire structure.

In addition, the structure comprises two plates which serve as support and spacers for the fuel cells. For the production of these perforated plates, it is necessary to use special production equipment, which considerably complicates the production of the whole structure and increases the purchase costs.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a support structure for supporting and maintaining the distance between fuel elements in the core of a water-water nuclear reactor, which increases operational reliability of the system and simplifies component production while reducing manufacturing costs.

This object is achieved by a support structure according to the invention adapted to support and maintain the mutual distance of the fuel elements in the core of a water-water nuclear reactor, which comprises a perforated bottom drum in which the lower ends of the support elements are fastened; a spacer for maintaining the distance between the fuel elements, wherein the support elements are hollow, have side openings and are located below each fuel element. It is an object of the invention that the upper ends of the support elements are supported against each other and together with the surrounding ring form a spacer.

The invention provides a support structure for supporting and maintaining the mutual distances between the fuel elements in the core of a water-water nuclear reactor, which is much more advantageous than the prior art, since in the present invention there is a support element under each fuel element.

The construction according to the invention is simplified and allows for easier production. This advantage is achieved, in particular, by the fact that the upper ends of the supporting elements are in contact with one another and are supported on one another, being surrounded by a circumferential ring around the periphery of the assembly. No special tools and equipment are required to manufacture the support elements.

An exemplary embodiment of a fuel cell support structure according to the invention is shown in the drawings, wherein FIG. 1 is a longitudinal section through a device for supporting and maintaining mutual distances between fuel cells in the core of a water-water nuclear reactor. 3, an axonometric view of the support element shown on an enlarged scale, and FIG. 4 is an overall axonometric view of the nuclear reactor.

The support structure for supporting and maintaining the mutual distances between the fuel elements 7 in the core of the nuclear reactor consists of a drum 1 (Fig. 1), the bottom 2 of which are formed by openings 3, 4 through which the heat transfer medium can pass into the inner space of the drum. 5 of the support elements 6 are fixed to the bottom 2 of the drum 1 in the openings 4. Above the support elements 6 fuel elements 7 are fastened. The upper ends 8 of the support elements 6 abut one another and the whole assembly is surrounded circumferentially by the peripheral ring 9 fuel cell distance system 7.

The outer surfaces of the upper ends 8 (FIGS. 1, 2) of the support elements 6 are in the form of polyhedra. The inner surface of the peripheral ring 9 is complementary to the peripheral surface of the set of upper ends 8 of the outer support elements 6.

In the upper ends 8 (Figs. 2, 3) of the support elements 6 are located clamping screws 10 (Fig. 3) to remove technological clearances. The lower ends 5 of the support elements 6 are fastened in the openings 4 of the bottom 2 of the drum 1 by means of threaded sleeves 11 which regulate the height position of the support elements 6. Holes 12 are formed in the side walls of the support elements 6 through which the heat transfer substance can pass to the fuel elements 7 ( 1) of a fissile material.

The inlet sockets 13 (FIG. 4) for the heat transfer fluid inlet and the outlet sockets 14 for the heat transfer fluid are formed on the shell 15 of the nuclear reactor.

The support structure according to the invention has the following effect.

The transfer of the heat transfer medium to the nuclear reactor and its removal takes place in the direction of the arrows indicated in FIG. 4, whereby the heat transfer medium is fed through the inlet pipe 13 and is discharged through the outlet pipe 14.

The shape of the bottom profile 2 of the drum 1 (FIG. 4), the location of the bottom 2 in the nuclear reactor jacket 15 and the number and size of the openings 3 (FIG. 1) in the bottom 2 are chosen such that Articles 7, was even and stable.

The heat transfer agent enters through the inlet sleeves 13 (FIG. 4) into the gap between the reactor jacket 15 and the drum 1 and is led through the openings 3, 4 (FIG. 1) into the interior of the drum 1.

The shape of the profile of the curved gap or channel between the bottom 2 of the drum 1 and the wall of the reactor jacket 15 and throttling the flow of the heat carrier in the openings of the drum bottom 2 ensures elimination of pulsations and equalization of the velocity field of the heat carrier below the bottom 2. 3) into the support elements 6 from which it enters the fuel cells 7 (Fig. 1). The heat transfer medium heated in the fuel cells then exits through the exit sleeves 14 out of the nuclear reactor.

The support structure according to the invention has certain technical-economic effects which are achieved by the fact that no special devices and tools are required for the production of this support structure.

Claims (1)

SUBJECT OF THE INVENTION A support structure for supporting and maintaining the mutual distance of fuel cells in the core of a water-water nuclear reactor, comprising a perforated bottom drum in which support members are fastened at their lower ends, over which fuel cells and a spacing system for maintaining the fuel cell distance wherein the support elements are hollow, have side openings and are located below each fuel cell, characterized in that the upper ends (8) of the support elements (6) are leaning against each other and form a spacer together with the surrounding ring (9) system.