Fuel channel for a nuclear power boiling water reactor

A fuel channel for a nuclear power boiling water reactor, the fuel channel being configured to include a bundle of fuel rods with nuclear fuel, the fuel channel being made of sheet materials and having an elongated shape and defining a longitudinal direction and comprises:

• an assembly of four discrete major sides, each of said major sides extending between a first axial end and a second axial end of the fuel channel and each of which have an elongated shape in said longitudinal direction and which are connected to each other such that a corner, which has an elongated shape and which extends in said longitudinal direction, is formed where any two of said major sides that are adjacent to one another, meet;
• wherein said major sides are connected to each other such that the fuel channel has four of said corners;
• wherein each of said major sides defines an inner surface facing an interior area of the fuel channel, and an outer surface facing outwardly from the fuel channel;
• and
• in each of at least two of said corners the sheet materials from two of the major sides that are adjacent to one another, overlap with each other such that each said corner defines a corner region with overlapping sheet materials, said corner region defined by a first of said sheet materials from one of the major sides that are adjacent to one another and an overlapping one of a second of said sheet materials from the other of the major sides that are adjacent to one another;
• wherein said corner region with said overlapping sheet materials extends in said longitudinal direction along at least fifty percent of the length of the fuel channel;
• wherein in each of said at least two corners, said first of said sheet materials and said second of said sheet materials overlap with each other to form an overlapping region in which a space is formed between said first of said sheet materials and said second of said sheet materials;
• wherein in at least one of said corners, an inner one of said overlapping sheet materials is substantially straight, while an outer one of said overlapping sheet materials is configured to form an outer corner shape, such that said space, as seen in a cross section of the fuel channel, has substantially a triangular shape, wherein one corner is bent, or arc shape which is limited by a straight portion of the inner one of said overlapping sheet materials;
• and
• wherein in each said corner having said corner region with said overlapping sheet materials, the inner one of said overlapping sheet materials extends from a first of said major sides to a second, adjacent one of said major sides, wherein the first major side defines a first plane and the second major side defines a second plane, the first plane is perpendicular to the second plane, and the inner one of said overlapping sheet materials extends diagonally from a first point on the first plane to a second point on the second plane to form the space formed between said first of said sheet materials and said second of said sheet materials.