Statistical uncertainty analisis applied to the DRAGONv4 code lattice calculations and based on JENDL-4 covariance data
Paper in proceeding, 2012

In this paper, multi-group microscopic cross-section uncertainty is propagated through the DRAGON (Version 4) lattice code, in order to perform uncertainty analysis on k∞ and 2-group homogenized macroscopic cross-sections predictions. A statistical methodology is employed for such purposes, where cross-sections of certain isotopes of various elements belonging to the 172 groups DRAGLIB library format, are considered as normal random variables. This library is based on JENDL-4 data, because JENDL-4 contains the largest amount of isotopic covariance matrixes among the different major nuclear data libraries. The aim is to propagate multi-group nuclide uncertainty by running the DRAGONv4 code 500 times, and to assess the output uncertainty of a test case corresponding to a 17x17 PWR fuel assembly segment without poison. The chosen sampling strategy for the current study is Latin Hypercube Sampling (LHS). The quasi-random LHS allows a much better coverage of the input uncertainties than simple random sampling (SRS) because it densely stratifies across the range of each input probability distribution. Output uncertainty assessment is based on the tolerance limits concept, where the sample formed by the code calculations infers to cover 95% of the output population with at least a 95% of confidence. This analysis is the first attempt to propagate parameter uncertainties of modern multi-group libraries, which are used to feed advanced lattice codes that perform state of the art resonant self-shielding calculations such as DRAGONv4.

JENDL-4 covariance data

DRAGONv4 code

Latin hypercube sampling

Statistical uncertainty analysis

Author

Augusto Hernandéz Solís

Chalmers, Chemical and Biological Engineering, Nuclear Chemistry

Christophe Demaziere

Chalmers, Applied Physics, Nuclear Engineering

Christian Ekberg

Chalmers, Chemical and Biological Engineering, Nuclear Chemistry

Arvid Ödegård Jensen

Chalmers, Chemical and Biological Engineering, Nuclear Chemistry

International Conference on the Physics of Reactors 2012: Advances in Reactor Physics, PHYSOR 2012; Knoxville, TN; United States; 15 April 2012 through 20 April 2012

Vol. 4 2960-2974
978-162276389-4 (ISBN)

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