NUCLEAR FUEL ASSEMBLY

PURPOSE:To improve heat transfer characteristic of the position at which a CPR is lowered in the vertical direction of a reactor core by providing a turbulent promoting member of coolant at the upstream position of a spacer among fuel rods. CONSTITUTION:When a fuel assembly is installed in a reactor core and nuclear reaction is produced, the coolant which is flowed in from a lower stay plate rises in boiling in a channel box 5. The coolant passes from a first spacer to a fifth spacer successively, encounters a wire grid 6, comes in contact with a metal wire 7 and passes a sixth spacer 2F. Therefore, the upstream side heat transfer characteristic of the sixth spacer 2F can be improved.