Multidimensional Space-Time Nuclear-Reactor Kinetics Studies—Part II: Experimental

Experimental data that test the validity of a numerical solution of the transient few-group neutron diffusion and delayed precursor equations in two-dimensional hexagonal geometry are presented. The experiments involve free fall insertion of ²³⁵U-bearing rods into an off-center location of a large critical, heavy-water-moderated lattice. The resulting transient flux tilts are strongly influenced by delayed neutron holdback. The calculated flux tilts agree with the measured flux tilts within the small uncertainty of the measurements. The data and input to the calculations are presented in sufficient detail to allow other methods of solution to be tested.