[en] In the 1950's, a series of critical bare sphere experiments was performed using uranyl nitrate solutions poisoned with boron as boric acid. Both the ²³⁵U and ²³³U isotopes were used. These experiments and others without poison have been used as the basis for performing a series of correlations with various code and cross section combinations used at Rockwell Hanford Operations (Rockwell). A selected combination was then used to calculate a set of curves which provide limiting parameters for boron-poisoned ²³⁵U--H₂O mixtures. These curves may be used to provide limits for equipment design of simple geometries or to provide a basis for comparison when designing a more complex system