Methods and Issues for the Combined Use of Integral Experiments and Covariance Data: Results of a NEA International Collaborative Study

New approaches to provide feedback from nuclear and covariance data adjustment for effective improvement of evaluated nuclear data files

“…The statistical adjustment was performed using the method described in [2] and widely used in previous studies. This method has been shown to be equivalent to similar adjustment method, as shown by the extensive comparison of [2].…”

“…Subgroup 26 [1] was the starting point to promote data covariance development, to allow meaningful uncertainty analysis and target accuracy requirements; Subgroup 33 [2] has succeeded in providing a deeper understanding of nuclear data and associated covariance adjustment methods, the role of integral experiment uncertainties and of their application. The ongoing WPEC subgroup 39 [3] is intended to provide criteria and practical approaches to use effectively the results of sensitivity analyses and neutron cross section adjustments for feedback to evaluators and differential measurement experimentalists in order to improve without ambiguities the knowledge of neutron cross sections, uncertainties, and correlations to be used in a wide range of applications.…”

Physics challenges for advanced fuel cycle assessment

“…However, for credible assessments of the nuclear data impact on innovative reactor systems design, it is necessary to use accurate, science-based covariance data that should account for the most important reactions of the most important isotopes. This work has been the object of research in many leading laboratories and a summary indication can be found in [24]. The availability of much improved covariance data has allowed to revise the results of [23], as it will be documented in what follows.…”

A stress test on 235U(n, f) in adjustment with HCI and HMI benchmarks

“…The Subgroup SG33 had accomplished a study on "Methods and issues for the combined use of integral experiments and covariance data" [2], which was mainly devoted to the study of the methods of nuclear data adjustment. After that, a further topic "Methods and approaches to provide feedback from nuclear and covariance data adjustment for improvement of nuclear data files" has been studied in SG39 since 2013.…”