DE2128368C3 - Spring element for spacers of nuclear reactor fuel bundles - Google Patents

Description

35

The invention relates to a spring element consisting of four side parts and having a square cross-section for insertion into the crossing points of the spacer grids of nuclear reactor fuel assemblies forming webs, wherein between the upper and the lower portion of each side part of the spring element a spring clip is available, each of which has a support for one in the relevant mesh dei> Forms spacer grid used fuel rod of the fuel assembly

Such a spring element is known from DE-PS 19 30 981

In this spring element, the resilient support points do not influence each other, which is an important one This is the requirement for such spring elements

A disadvantage is that the known spring element is quite expensive. This is not in here First and foremost, a question of production costs, which is much more serious because of the large mass of the Spring element the neutron economy of the nuclear reactor is worsened. That's because the for Spring elements required materials !, for example Inconel, a high neutron absorption cross-section to have.

Difficulties can arise with the well-known «> spring element when it comes to compensation of manufacturing inaccuracies on a larger spring deflection of the resilient support points Because the webs are bent out of a rigid side part, the two ends of the webs can do not change in their distance, so that there is a fairly hard spring characteristic The disadvantage has been mitigated in this known embodiment in that the webs are bent several times are. This makes the spring characteristic softer, but there is now the risk that it will fall into the Permanent deformation occurs at bending points

Spring elements of the type mentioned are also from DE-OS 15 64434 and DE-OS 17 64185 known. Since these spring elements are very complex with regard to their mass and the webs are rigid Side parts are bent out, they have in principle the same disadvantages as that from the DE-OS 19 30 981 known spring element

The invention is based on the object of providing a spring element of the type mentioned at the beginning to improve that it is as simple as possible to construct because of the neutron economy Has the lowest possible mass and in which a good spring characteristic is given without it being a disadvantageous, mutual influence of the resilient Support points comes

According to the invention, this object is achieved by the features of the characterizing part of the claim 1 solved

The advantages of the spring element according to the invention are primarily that two opposite fixed spring clip by changing the height of the spring element to a uniform Can adjust contact pressure without them are hindered by the rest of the spring clip or without affecting the rest of the spring clip would be. If all four spring clips were with at both ends the sections of the spring elements firmly connected, so all spring clips would influence each other.

The two spring clips each connected to a section of the spring elements only at one end are completely independent of each other.

An embodiment of the invention is shown in the drawing and described below. It shows

F i g. 1 a side view of the spring element,

2 shows a plan view of the spring element according to Fig. 1.

As the top view Fig. 2 shows, there is Spring element made up of four side parts 1, 2, 3 and 4. All side parts each have an upper section 5 and a lower section. With two opposite Side panels 2,4 are the top and bottom sections 5, 6 each firmly connected to one another by a spring clip 7, 10. The same spring clips 8, 9 are also available for the two remaining side walls 1, 3, but the spring clips 8, 9 are only here connected on one side to the upper portion of the side walls 1 and 3, while on the each lower section rest longitudinally displaceable. For this purpose, the spring clips 9, 8 are at the lower end slightly bent outwards, which can be seen from FIG. 1 can be found

The spring clips themselves are convexly curved over their length, each with at least one resilient one To form support point for a fuel rod. Furthermore, the spring clips 7, 8, 9, 10 are useful made narrower than the upper and lower sections 5, 6 of the side parts 1, 2, 3 and 4.

In order to prevent excessive deformation of the webs under all circumstances, the upper and lower sections 5 and 6 support points 11 and 12 pushed out against the fuel rods at the maximum permissible deflection of the spring clips 7, 8, 9.10 are applied.

To simplify their production, two side parts 1, 2 and 3, 4 are each made of one at 90 ° bent sheet metal part manufactured

In order to work reliably, the spring elements are with slight play in the crossing points of the Bars used. The mutual influence of the two opposite spring clips that are firmly attached to their upper and lower sections are connected

then compensated by the fact that the spring elements as a result of the play after inserting the fuel rods across the intersection points, that the same force acts on two opposing fuel rods The two remaining spring clips are not affected by the fixed spring clip, because they can each be longitudinally displaced on one section are.

1 sheet of drawings

Claims (3)

Patent claims: 1. Spring element consisting of four side parts with a square cross-section for insertion into the Crossing points of the webs forming the spacer grids of nuclear reactor fuel assemblies, wherein between the upper and lower portions of each side part of the spring element each a spring clip is available, each of which has a support for one in the relevant mesh of the The fuel rod of the fuel assembly used as a spacer grid, characterized in that that with two opposite side parts (1, 3) the upper and lower section is only firmly connected to one another by the spring clip (7, 10), while the remaining Side parts (2, 4) of the spring clip is firmly connected to only one section each while it is on the respective other section rests longitudinally displaceably, and that the spring element with play in the cross points of the webs can be used 2. Spring element according to claim 1, characterized in that the spring clip is narrower than that upper and lower sections (5,6) of the side parts (1,2,3,4) are. 3. Federbment according to claims 1 and 2, characterized in that d & 3 the upper and lower sections (e.g. 5, 6) support points (e.g. 11, 12), against which the fuel rods at the maximum permissible deflection of the spring bend] (7, 8,9,10).