Use of Covariances in a Consistent Data Assimilation for Improvement of Basic Nuclear Parameters in Nuclear Reactor Applications: From Meters to Femtometers

New paradigm for nuclear data evaluation

“…The major correlations are shown and discussed in Ref. [4] but missing ν eliminates the most important factor. Interestingly, the Jezebel benchmark practically does not correlate the PFNS parameters with the remaining ones.…”

“…The advantage of this approach is that all physics constraints are observed and the predictive power of the model is exploited to interpolate and extrapolate to experimentally unexplored quantities and energy regions. Figure 1 illustrates the assimilation of 239 Pu cross sections and Prompt Fission Neutron Spectra (PFNS) to the Jezebel benchmark performed within the exploratory work on the assimilation methodology [4] carried out by a collaboration between Brookhaven and Idaho National Laboratories. In this exercise 53 model parameters were varied out of which 22 were modified.…”