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Low-Fidelity Cross Section Covariances for 219 Fission Products in the Fast Neutron Region.

DE2007915433

Publication Date	2007
Personal Author	Pigni, M. T.; Herman, M.; Oblozinsky, P.; Rochman, D.
Page Count	56
Abstract	An extensive set of covariances for neutron cross sections in the energy range 5 keV-20 MeV has been developed to provide initial, low-fidelity but consistent uncertainty data for nuclear criticality safety applications. The methodology for the determination of such covariances combines the nuclear reaction model code EMPIRE, which calculates sensitivity to nuclear reaction model parameters, and the Bayesian code KALMAN to propagate uncertainty of the model parameters to cross sections. Taking into account the large scale of the project (219 fission products), only partial reference to experimental data has been made. Therefore, the covariances are, to a large extent, derived from the perturbation of several critical model parameters selected through the sensitivity analysis. These parameters define optical potential, level densities and pre-equilibrium emission. This work represents the first attempt ever to generate nuclear data covariances on such a scale.
Keywords	Fission products Fast neutrons Cross sections Nuclear data collections Radioactive materials Emission Parameters Criticality Safety
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Brookhaven National Lab., Upton, NY. Dept. of Energy Sciences and Technology.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200805
Contract Number	DE-AC02-98CH10886

Low-Fidelity Cross Section Covariances for 219 Fission Products in the Fast Neutron Region.

Low-Fidelity Cross Section Covariances for 219 Fission Products in the Fast Neutron Region.
DE2007915433

Publication Date	2007
Personal Author	Pigni, M. T.; Herman, M.; Oblozinsky, P.; Rochman, D.
Page Count	56
Abstract	An extensive set of covariances for neutron cross sections in the energy range 5 keV-20 MeV has been developed to provide initial, low-fidelity but consistent uncertainty data for nuclear criticality safety applications. The methodology for the determination of such covariances combines the nuclear reaction model code EMPIRE, which calculates sensitivity to nuclear reaction model parameters, and the Bayesian code KALMAN to propagate uncertainty of the model parameters to cross sections. Taking into account the large scale of the project (219 fission products), only partial reference to experimental data has been made. Therefore, the covariances are, to a large extent, derived from the perturbation of several critical model parameters selected through the sensitivity analysis. These parameters define optical potential, level densities and pre-equilibrium emission. This work represents the first attempt ever to generate nuclear data covariances on such a scale.
Keywords	Fission products Fast neutrons Cross sections Nuclear data collections Radioactive materials Emission Parameters Criticality Safety
Source Agency	Technical Information Center Oak Ridge Tennessee
Corporate Authors	Brookhaven National Lab., Upton, NY. Dept. of Energy Sciences and Technology.; Department of Energy, Washington, DC.
Supplemental Notes	Sponsored by Department of Energy, Washington, DC.
Document Type	Technical Report
NTIS Issue Number	200805
Contract Number	DE-AC02-98CH10886