Abstract: The invention concerns a method of estimating when dryout may occur in a nuclear light water reactor of the boiling water reactor kind. The method includes the use of a formula which expresses the local dryout property of the nuclear reactor. The formula includes at least a first and a second factor. The first factor is a first function that describes how the dryout property depends on the flow of the cooling medium through the nuclear fuel arrangement. The second factor is a second function that describes how the dryout property depends on the axial power profile of the nuclear fuel arrangement. The first and the second functions describe said flow dependence and said axial power profile dependence independently of each other. The invention also concerns a nuclear energy plant, a computer program product (23) and a method of operating a nuclear energy plant.

Abstract: The invention concerns a method of estimating when dryout may occur in a nuclear light water reactor of the boiling water reactor kind. The method includes the use of a formula which expresses the local dryout property of the nuclear reactor. The formula includes at least a first and a second factor. The first factor is a first function that describes how the dryout property depends on the flow of the cooling medium through the nuclear fuel arrangement. The second factor is a second function that describes how the dryout property depends on the axial power profile of the nuclear fuel arrangement. The first and the second functions describe said flow dependence and said axial power profile dependence independently of each other. The invention also concerns a nuclear energy plant, a computer program product (23) and a method of operating a nuclear energy plant.

Abstract: A fuel assembly for a pressurized water reactor that includes a bottom nozzle, a plurality of elongated guide thimbles projecting upwardly from the bottom nozzle, an array of fuel rods, a plurality of support grids axially spaced along the guide thimbles, and at least two Intermediate Flow Mixing grids, which may have different configurations of mixing device formations, disposed between pairs of non-uniformly spaced, adjacent support grids at selected locations.