Use of 2D/3D data for peak cladding temperature uncertainty studies

In August 1988, the Nuclear Regulatory Commission (NRC) approved the final version of a revised rule on the acceptance of emergency core cooling systems (ECCS). The revised rule allows ECCS analysis based on best-estimate methods provided uncertainties in the prediction of prescribed acceptance limits are quantified and reported. To support the revised rule, the NRC developed the Code Scaling, Applicability, and Uncertainty (CSAU) evaluation methodology. Data from the 2D/3D program have been used in a demonstration of the CSAU methodology in two ways. First, the data were used to identify and quantify biases that are related to the implementation of selected correlations and models in the thermal-hydraulic systems code TRAC-PF1/MOD1 as it is used to calculate the demonstration transient, a large-break loss-of-coolant accident. Second, the data were used in a supportive role to provide insight into the accuracy of code calculations and to confirm conclusions that are drawn regarding specific CSAU studies. Examples are provided illustrating each of these two uses of 2D/3D data