Critical heat flows in light water reactor fuel elements

An empirical correlation is presented for the computation of critical thermal flow densities derived from own measurements on models with axially even and radially even and uneven heat generation. The results are presented tested on a sample of published experimental data and correlations presented in the literature are critically evaluated. The correlation also includes the influence of axially uneven heat flow distribution on departure nucleate boiling and the measure of safety is given for the rated parameters of the WWER 1000 reactor. (J.B.)