TY - GEN

T1 - Extensive set of low-fidelity cross sections covariances in fast neutron region

AU - Pigni, M. T.

AU - Herman, M.

AU - Obložinský, P.

PY - 2008

Y1 - 2008

N2 - We produced a large set of neutron cross section covariances in the energy range of 5 keV - 20 MeV. The covariance matrices were calculated for 307 isotopes divided into three major regions: structural materials, fission products, and heavy nuclei. These results have been developed to provide initial, but consistent estimates of covariance data for nuclear criticality safety applications. The methodology for the determination of such covariance matrices is presented. It combines the nuclear reaction model code EMPIRE which calculates sensitivity of cross sections to nuclear reaction model parameters, and the Bayesian code KALMAN that propagates uncertainties of the model parameters to cross sections. Taking into account large number of materials, only marginal reference to experimental data was made. The covariances were derived from the perturbation of several key model parameters selected by the sensitivity analysis. These parameters refer to the optical model potential, the level densities and the strength of the pre-equilibrium emission. This work represents the first try ever to generate nuclear data covariances on such a large scale.

AB - We produced a large set of neutron cross section covariances in the energy range of 5 keV - 20 MeV. The covariance matrices were calculated for 307 isotopes divided into three major regions: structural materials, fission products, and heavy nuclei. These results have been developed to provide initial, but consistent estimates of covariance data for nuclear criticality safety applications. The methodology for the determination of such covariance matrices is presented. It combines the nuclear reaction model code EMPIRE which calculates sensitivity of cross sections to nuclear reaction model parameters, and the Bayesian code KALMAN that propagates uncertainties of the model parameters to cross sections. Taking into account large number of materials, only marginal reference to experimental data was made. The covariances were derived from the perturbation of several key model parameters selected by the sensitivity analysis. These parameters refer to the optical model potential, the level densities and the strength of the pre-equilibrium emission. This work represents the first try ever to generate nuclear data covariances on such a large scale.

UR - http://www.scopus.com/inward/record.url?scp=79953878401&partnerID=8YFLogxK

M3 - Conference contribution

AN - SCOPUS:79953878401

SN - 9781617821219

T3 - International Conference on the Physics of Reactors 2008, PHYSOR 08

SP - 154

EP - 161

BT - International Conference on the Physics of Reactors 2008, PHYSOR 08

PB - Paul Scherrer Institut

T2 - International Conference on the Physics of Reactors 2008, PHYSOR 08

Y2 - 14 September 2008 through 19 September 2008

ER -