The change in regulation requirements on the Emergency Core Cooling Systems (ECCS) allowing the use of best-estimate codes for licensing accident analysis requires the uncertainty evaluation of calculational results to account for numerical approximations, empirical correlations, plant model …
The Best Estimate Plus Uncertainty (BEPU) methods, and specifically the statistical approach that propagates the input uncertainty to the output results to generate the tolerance intervals, are nowadays used worldwide by engineering organizations to estimate the uncertainties of the code calculations
ENSO offers a step forward in uncertainty analyses by applying it in Severe Accident scenario