Revisitation of the studies on covariance data and adjustment analysis: A tribute to M. Salvatores for his great works and remaining future tasks

Abstract Based on the great works of Massimo Salvatores the research studies on the cross-section covariance data and the cross-section adjustment have been revisited, and the important issues and the remaining future tasks have been discussed. On the covariance studies the estimation of the covariance data suitable to predicting neutronics parameters uncertainty has been discussed, and it was found that for MA nuclides covariance data there is a case where the conventional covariance data should be increased. On the adjustment studies the Salvatores report indicated that the negative correlation of after-adjustment covariance data has large effects from numerical calculations, and in this paper the negative correlation effect has been discussed from the theoretical point of view.