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Apr 19 – 22, 2022
Vienna, Austria
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Objectives and Status of Neutronics Sub-exercises of the OECD/NEA Benchmark for Uncertainty Analysis in Modelling for Design, Operation and Safety Analysis of SFRs

Apr 20, 2022, 11:16 AM
Vienna, Austria

Vienna, Austria

ORAL Track 6. Modelling, Simulations, and Digitilization 6.1 Neutronics


Friederike Bostelmann (Oak Ridge National Laboratory)


The OECD/NEA Benchmark for Uncertainty Analysis in Modeling (UAM) for Design, Operation and Safety Analysis of Sodium-cooled Fast Reactors (SFRs) was launched in 2015 to study reactivity feedback coefficients and their uncertainties for a medium-sized 1,000 MWth metallic core and a large 3,600 MWth oxide core. In addition to investigations of the full core level, stand-alone multi-scale neutronics analyses of several sub-exercises on the fuel pin and assembly level were identified to be relevant for a systematic assessment of the influence of nuclear data in fast reactor simulations. Especially when studying simple models, comparisons between computational results using different methods, models, and applied nuclear data libraries can unveil the major drivers of observed differences and obtained uncertainties.
The original specifications were therefore amended by neutronics sub-exercise specifications covering a fuel pin cell, a fuel assembly, and a super cell that includes a central absorber assembly surrounded by fuel assemblies for each of the two reactor designs. The nominal values and corresponding uncertainties of the eigenvalue, reactivity effects, and collapsed cross sections are requested. For the eigenvalue and reactivity effects, the top contributing nuclide-reaction pairs to the calculated output uncertainties are requested as well.
Up to now, 15 contributions to these sub-exercises from 9 international institutions were received. The preliminary results display good agreement in the calculated nominal results for calculations that were based on the same nuclear data library. A similar conclusion was drawn for the comparison of submitted uncertainties: differences in the applied covariance data dominate the cause of differences between results that were obtained using different methods for the neutron transport calculation and uncertainty quantification.
This paper provides an overview of the objective and status of the sub-exercises of the standalone neutronics phase of the UAM SFR benchmark. Preliminary comparisons between submitted results will be presented and preliminary conclusions of this part of the benchmark will be discussed.

Speaker's email address
Speaker's title Ms
Country/Int. organization United States of America
Affiliation/Organization Oak Ridge National Laboratory

Primary author

Friederike Bostelmann (Oak Ridge National Laboratory)


Alexander Aures (GRS) Prof. Andreas Pautz (Paul Scherrer Institut) Chenghui Wan (NECP) Deokjung Lee (UNIST) Emil Fridman (Helmholtz-Zentrum Dresden-Rossendorf) Emil Fridman (HZDR) Ian Hill (OECD/NEA) Ishita Trivedi (NCSU) Jason Hou (NCSU) Kaiyue Zeng (NCSU) Kiril Velkov (GRS) Kostadin Ivanov (NCSU) Lauren Buiron (CEA) Nadine Berner (GRS) Nicolas Stauff (Argonne National Laboratory) Qiao Liang (NECP) Winfried Zwermann (GRS) Xianan Du (UNIST) Youqi Zheng (NECP) Yunki Jo (UNIST)

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