Patent ID: 7760842

Claim:
A method of estimating when dryout may occur in a nuclear light water reactor of the boiling water reactor kind, which reactor includes a nuclear fuel arrangement, which method is characterised in that it includes: receiving data that indicates operation parameters for the reactor; and processing the data by the use of a formula which expresses the local dryout property of the nuclear reactor, wherein said formula includes at least a first and a second factor, wherein 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 and the second factor is a second function that describes how the dryout property depends on the axial power profile of the nuclear fuel arrangement, wherein said formula also includes a third function, wherein the third function describes how the dryout property depends on the R-factor of the nuclear fuel arrangement, wherein the R-factor is the weighted local power influence from the neighbour nuclear fuel rods, wherein said third function is a factor in the formula, wherein said formula also includes a fourth function, wherein the fourth function describes how the dryout property depends on the pressure of the cooling medium in the nuclear fuel arrangement, and wherein said fourth function is a factor in the formula, wherein the first, second, third and fourth functions independently of each other describe said flow dependence said axial power profile dependence, said R-factor dependence and said pressure dependence respectively.