Spacer
A spacer for a fuel assembly for a light water nuclear reactor contains a plurality of intercrossed segments, which form a grid. The segments are formed from first and second metal strips which are assembled and provided with protruding parts or corrugations in such a way that the adjacent protruding parts are embodied in such a way that a flow component perpendicular to a vertical central plane which extends between the metal strips is applied to cold water running out from the flow sub-channel.
1. A spacer for a fuel assembly of a nuclear reactor cooled by light cooling water, comprising:
a multiplicity of crisscrossing webs forming a grid, each of said webs formed of interconnected first and second sheet-metal strips having corrugations shaped asymmetrically in relation to a vertical middle plane running between said sheet-metal strips such that in each case neighboring corrugations form an enclosed flow sub-channel for receiving the cooling water;
said flow sub-channel running oblique to a vertical and having a shape being asymmetric in relation to said vertical middle plane thereby imparting to the cooling water emerging from said flow sub-channel a flow component perpendicular to said vertical middle plane running between said sheet-metal strips; and
said asymmetric shape of said enclosed flow sub-channel and said asymmetric shape of said corrugations being predefined.
2. The spacer according to claim 1 , wherein said flow sub-channel has a first partial channel with a cross section formed by a first corrugation decreasing in a flow direction of the cooling water, and a second partial channel having a cross section formed by a second, neighboring corrugation increasing in the flow direction.
3. The spacer according to claim 1 , wherein:
said first sheet-metal strips have first corrugations alternately disposed in a longitudinal direction of said first sheet-metal strips;
said second sheet-metal strips have second corrugations alternately disposed in a longitudinal direction of said second sheet-metal strips; and
said first and second sheet-metal strips are assembled to form said webs such that each said flow sub-channel is formed by said first and second corrugations.
4. The spacer according to claim 1 , wherein said flow sub-channel has a downstream end and runs oblique to the vertical at least at said downstream end.
5. The spacer according to claim 4 , wherein the cooling water respectively emerging from said flow sub-channels which are mutually neighboring and inclined to a crossing point of two of said webs, have mutually opposed flow components perpendicular to the vertical middle plane such that a swirl flow is produced around said crossing point.
6. The spacer according to claim 5 , wherein swirl flows around mutually neighboring crossing points are respectively directed in an opposed fashion to each other along said web.
7. A fuel assembly comprising:
at least one spacer, containing:
a multiplicity of crisscrossing webs forming a grid, each of said webs formed of interconnected first and second sheet-metal strips having corrugations shaped asymmetrically in relation to a vertical middle plane running between said sheet-metal strips such that in each case neighboring corrugations form an enclosed flow sub-channel running oblique to a vertical and having a shape being asymmetric in relation to said vertical middle plane thereby imparting to cooling water emerging from said flow sub-channel a flow component perpendicular to said vertical middle plane running between said sheet-metal strips;
said asymmetric shape of said enclosed flow sub-channel and said asymmetric shape of said corrugations being predefined.
8. The fuel assembly according to claim 7 , wherein: said asymmetric shape of said corrugations is formed by predefined offset arches.
9. The spacer according to claim 1 , wherein: said asymmetric shape of said corrugations is formed by predefined offset arches.