New SCALE Sensitivity/Uncertainty Capabilities Applied to Bias Estimation and to Design of MIRTE Reference Experiments
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States)
- Institut de Radioprotection et de Sûrete Nucleaire (ISRN), Fontenay-aux-Roses (France)
New TSUNAMI tools of SCALE 6, TSURFER and TSAR, are demonstrated to examine the bias effects of small-worth test materials, relative to reference experiments. TSURFER is a data adjustment bias and bias uncertainty assessment tool, and TSAR computes the sensitivity of the change in reactivity between two systems to the cross-section data common to their calculation. With TSURFER, it is possible to examine biases and bias uncertainties in fine detail. For replacement experiments, the application of TSAR to TSUNAMI-3D sensitivity data for pairs of experiments allows the isolation of sources of bias that could otherwise be obscured by materials with more worth in an individual experiment. The application of TSUNAMI techniques in the design of nine reference experiments for the MIRTE program will allow application of these advanced techniques to data acquired in the experimental series. The validation of all materials in a complex criticality safety application likely requires consolidating information from many different critical experiments. For certain materials, such as structural materials or fission products, only a limited number of critical experiments are available, and the fuel and moderator compositions of the experiments may differ significantly from those of the application. In these cases, it is desirable to extract the computational bias of a specific material from an integral keff measurement and use that information to quantify the bias due to the use of the same material in the application system. Traditional parametric and nonparametric methods are likely to prove poorly suited for such a consolidation of specific data components from a diverse set of experiments. An alternative choice for consolidating specific data from numerous sources is a data adjustment tool, like the ORNL tool TSURFER (Tool for Sensitivity/Uncertainty analysis of Response Functionals using Experimental Results) from SCALE 6.1 However, even with TSURFER, it may be difficult to examine a single experiment and differentiate bias due to a test material from bias due to other materials such as fuel and moderator. An alternative method is to perform two experiments on the same critical assembly, one with and one without the test material, and examine differences in the biases due to the introduction of the test material. Techniques to extract a computational bias from pairs of replacement experiments and project that bias, with an associated bias uncertainty, to an application system are described herein.
- Research Organization:
- Oak Ridge National Laboratory (ORNL), Oak Ridge, TN (United States); Inst. de Radioprotection et de Sûrete Nucleaire (ISRN), Fontenay-aux-Roses (France)
- Sponsoring Organization:
- USDOE National Nuclear Security Administration (NNSA), Nuclear Criticality Safety Program (NCSP)
- DOE Contract Number:
- AC05-00OR22725
- OSTI ID:
- 979232
- Resource Relation:
- Conference: NCSD 2009-Nuclear Criticality Safety Division Topical Meeting, Richland, WA (United States), 13-17 Sep 2009
- Country of Publication:
- United States
- Language:
- English
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