A Methodology for the Quantification of Uncertainty in Best Estimate Code Physical Models

Conference · Sat Jul 01 04:00:00 EDT 2006

OSTI ID:21016418

Vinai, Paolo; Macian, Rafael; Chawla, Rakesh ^[1]

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1. Paul Scherrer Institute, 5232 Villigen PSI (Switzerland)

A novel methodology based on a statistical non-parametric approach is presented in this paper. It can yield more objective quantification of code physical model uncertainty by making use of model performance information obtained from assessment studies of appropriate separate effect-tests. Uncertainties are quantified in the form of estimated probability density functions (pdfs) calculated with a newly developed non-parametric estimator, and, by applying a novel multi-dimensional clustering technique, the methodology takes into account the dependency of a model's uncertainty on system conditions. These uncertainties are the objective input information needed by code uncertainty propagation methodologies applied for assessing the accuracy of best estimate codes in nuclear systems analysis. The new methodology has been applied to the quantification of the uncertainty in the RETRAN-3D void prediction model and then used in the analysis of a double LOCA transient in an integral-test facility. This has clearly demonstrated the basic feasibility of the approach, as well as its advantages in yielding narrower uncertainty bands for quantifying the uncertainty in the code's prediction of the void fraction evolution during the transient. (authors)

• Research Organization: American Nuclear Society, 555 North Kensington Avenue, La Grange Park, IL 60526 (United States)
• OSTI ID: 21016418
• Country of Publication: United States
• Language: English

Related Subjects

21 SPECIFIC NUCLEAR REACTORS AND ASSOCIATED PLANTS
ACCURACY
CHARGES
FORECASTING
INFORMATION
LOSS OF COOLANT
PERFORMANCE
PROBABILITY DENSITY FUNCTIONS
SYSTEMS ANALYSIS
TEST FACILITIES
TRANSIENTS
VOID FRACTION
VOIDS