Nuclear data uncertainty propagation: Perturbation vs. Monte Carlo

Two methods of nuclear data uncertainty propagation are compared, using the same nuclear data uncertainties and criticality-safety benchmarks. The first method, based on perturbation theory uses covariance files, covariance processing and the perturbation card of MCNP. The second method makes use of a large number of MCNP calculations, all alike, but using different random nuclear data libraries, consistent with the covariance files of the first method. The consistency of the nuclear data used by both methods is checked and results for 33 criticality-safety benchmarks are presented. Relatively good agreements are found, but depending on the benchmark cases, differences due to the elastic cross-section, nu-bar, angular and energy distributions are observed. (C) 2011 Elsevier Ltd. All rights reserved.