Analysis of Exponential Experiments with Lattices of Plutonium in Heavy Water

In this paper Pu-Al-D₂O lattice experiments are analyzed with primarily ENDF/B data and methods based on asymptotic theory. The effects of varying the ²³⁹Pu cross sections in the unresolved-resonance range are calculated. The uncertainties associated with the determination of the radial bucklings are reduced with the use of one-dimensional transport calculations in the radial direction and an assumed exponential dependence in the axial direction. Two-dimensional calculations for a few of the lattices are made to calculate relaxation lengths as well as to determine the applicability of one-dimensional or asymptotic theory methods.