Program - Brookhaven National Laboratory

LC 5 5:00 PM
Uncertainty Study of Nuclear Model Parameters for the n+ 56 Fe Reactions in the Fast
Neutron Region Below 20 MeV
Junfeng Duan, Erwin Alhassan, Cecilia Gustavsson, Stephan Pomp, Henrik Sjöstrand, Michael Osterlund
Division of applied nuclear physics, Department of physics and astronomy, Uppsala University, Box 516,
751 20, Uppsala, Sweden
Arjan Koning, Dimitri Rochman
Nuclear Research and consultancy Group(NRG),P.O. Box 25, 3 Westerduinweg, 1755 ZG Petten, The
Netherlands
With the development of Gen-IV reactors, advanced fuel cycles, transmutation and shielding design, the
need of neutron cross section covariance data (uncertainties and correlations) is becoming increasingly
important. In this work, random parameter variation is applied tothe neutron optical model potential
(OMP) of 56 Fe by using the Total Monte Carlo method [1]. The uncertainties of total, elastic, non-elastic
cross section as well as angular distribution and their correlations have been obtained based on the existing
experimental data. Also, by using a parameter rejection method based on experimental data, a correlation
matrix for the OMP parameters is obtained. The impact of these OMP parameter uncertainties on all
partial channels for n+ 56 Fe reaction is investigated with the TALYS nuclear model code[2]. Furthermore,
the impact of other model parameter uncertainties such as level density and gamma width on each partial
channel is investigated. By using random sampling within the appropriate uncertainty ranges, more than
300 random evaluations of 56 Fe are presented. These are provided for reactor simulation codes for nuclear
data error propagation.
[1] Koning, A.J., and Rochman, D., 2008. Towards sustainable nuclear energy: Putting nuclear physics
to work. Annals of Nuclear Energy 35, p. 2024-230. [2] Koning, A.J., Hilaire S., Duijvestijn, M.C., 2007.
TALYS-1.0. In: Bersillon, O., Gunsing, F., Bauge, E., Jacqmin, R., Leray, S. (Eds.), Proceedings of the
International Conference on Nuclear Data for Science and Technology, Nice, France, 22-27 April, EDP
Sciences, p. 211.
LC 6 5:15 PM
Monte Carlo Sensitivity and Uncertainty Analysis with Continuous-Energy Covariance
Data
Ho Jin Park
Korea Atomic Energy Research Institute
Hyung Jin Shim, Chang Hyo Kim
Seoul National University
In the Monte Carlo (MC) sensitivity and uncertainty (S/U) analysis [1] with continuous-energy cross section
libraries, the sensitivities of a tallied parameter can be estimated based on the multi-group relative
covariance data. In our previous study [2], it was presented that the k uncertainties estimated by using
different continuous-energy cross section libraries but the same multi-group covariance data may be significantly
different each other because of limitation of the relative covariance approach. In order to overcome
the multi-group approximation of the covariance data, we present a method to directly use the covariance
files in the MC sensitivity calculations. The k uncertainties due to the multi-group and continuous-energy
covariance data are compared for various criticality benchmark problems.
Corresponding author: Hyung Jin Shim
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