The critical heat fluxes (CHF) of a 12-ft, axially nonuniform heat flux shape are compared with those of a 6-ft partial length of the same flux shape. For the shape used, the 6-ft partial flux shape predicts the critical heat flux performance of the full 12-ft flux shape. The location of the CHF—and hence the CHF itself—can vary considerably on axially nonuniform flux shapes without appreciably altering the corresponding channel power.