A theoretical analysis of the reactivities of experimentally measured uniform light-water-moderated and -reflected PuO2 in UO2 lattices and Pu(NO3)4 solutions is presented here. The mixed-oxide single-rod lattices are homogenized by the use of multigroup integral transport theory, and diffusion theory is used for the cylindrical core calculations. The cross sections are derived from the WIMS library. The homogeneous spherical Pu(NO3)4 solutions are analyzed by discrete-ordinates transport theory. Due to the small size of these assemblies, it is necessary that one-dimensional core calculations also be performed with a cross-section energy-group structure that can accurately represent neutron slowing down and thermalization at the core-reflector interface. Due to the uncertainty present in the Battelle Northwest Laboratories analyses of the mixed-oxide lattices, the agreement of our predictions for these lattices with measurement is considered to be more satisfactory. Our reactivity predictions agree generally within +0.6% of measurements for the mixed-oxide lattices and within 1% for the solution systems.