Abstract:
The core of a pressurized water reactor is assembled in such a way that if the fuel rods on the edge of the core bend, said bending is respectively oriented outwards in a convex manner. When the reactor is in operation, forces arise which increase the size of small gaps between said fuel rods at the expense of greater gaps and counteract the bending effect of said fuel rods.
Abstract:
The invention relates to a fuel element (4) for a pressurised water nuclear reactor. A plurality of fuel rods (10) extending in an axial direction are guided into a plurality of quadratic spacers (12) which are arranged at a distance from each other and are grid-shaped. The edge thereof is formed, respectively, by four edge web pieces (14a, b). At least one spacer (12) has at least two edge web pieces (14a, b) which are different from each other and which are used to produce a force (F) acting upon flowing cooling water (K) on the fuel element (4) on the plane of said spacer (12) in a transversal manner in relation to the axial direction. As a result, a systematic, predetermined deformation of a core (5), comprising said fuel elements, is produced and is taken into account in the configuration thereof .
Abstract:
The invention relates to a fuel element for a compressed water nuclear reactor. Said fuel element contains a plurality of fuel rods that are guided into a plurality of axially interspaced spacers (4) respectively forming a quadratic grid consisting of connecting elements (141-17, 161-17) and comprising a plurality of holes (6) that are arranged in rows (10) and columns (8). A control rod guiding tube (12) is respectively guided through a number of said holes (6), and the spacer (4) is structurally embodied in such a way that when a limiting force acting laterally on the spacer (4) is exceeded, a deformation is triggered exclusively in a region of the spacer (4) located outside an inner region (18) containing the control rod guiding tubes (12).
Abstract:
A fuel element for a pressurized water reactor contains a multitude of fuel rods, which are guided inside a number of axially interspaced spacers (4) that, together, form a square grid having a multitude of holes (6) arranged in rows (10) and columns (8). A supporting tube is passed through a number of these holes and is joined with material fit inside said holes to the spacer (4) that does not contain any fuel. According to the invention, the supporting tubes are spread out in positions (Pa, Pb, Pc) within the grid in such a manner that, with a predetermined number of supporting tubes and a distribution thereof within the grid, which is rotationally symmetric around 90 DEG with regard to a rotation about the central axis of the spacer (4), said central axis being perpendicular to the grid plane, the number of rows (10f) and columns (8f) that do not contain any supporting tubes is minimal. In addition, it is ensured that optionally remaining inner lying rows (10f) and columns (8f) that do not contain any supporting tubes are not situated next to one another.
Abstract:
Disclosed is a fuel element (2) for a pressurized water nuclear reactor, comprising a fuel element base (12) and a support structure for a plurality of fuel rods (4), which is mounted on said fuel element base (12). Cooling water (K) flows between the fuel rods (4) in an axial direction (3), said cooling water (K) flowing into the fuel element base (12) at a non-homogeneous axial speed distribution. A flow-directing structure is provided in the area of the fuel element base (12) for homogenizing the axial speed distribution of the cooling water (K) that enters between the fuel rods (4), thus reducing the risk of the fuel rods being subjected to flow-induced vibrations.
Abstract:
The invention relates to a fuel element (2) for a pressurised water reactor, containing an end part (4) and a spring arrangement (8a, b) which can be impinged upon by pressure by reducing the projection (L) and which protrudes over the end part (4) with a projection (L). Said spring arrangement comprises at least one first spring element (10a, b) and one second spring element (12a, b) which is permanently serially connected. One of the spring elements (10a, b) is prestressed in such a manner that the spring rate (ca, cb) of the spring arrangement (8a, b) is exclusively determined by the other spring element (12a, b) below a predetermined defining force (FGa, FGb).