LAUSR

Abstract There are many challenges associated with the proper assessment, evaluation, interpretation and use of nuclear data covariance. There are even topics on which the international nuclear data community has not reached a consensus as evidenced by the formation of a subgroup of the Working Party for Nuclear Data Evaluation Cooperation (WPEC) under the auspices of the Nuclear Energy Agency (NEA) dedicated to working on problems in nuclear data covariance. One of those issues is directly reflected in the disclaimer published with the ENDF/B-VIII.0 nuclear data library. This paper documents the effort undertaken to produce an augmented ENDF/B-VIII.0 nuclear data covariance library to be distributed and used with the upcoming release of the SCALE 6.3 code package. SCALE has a history of distributing a covariance library that is an edited version of the published ENDF/B release. The demonstrated need, the approach methodology and some preliminary results were published earlier in a pair of ORNL reports. The major contribution of this paper, in the spirit of scientific transparency and reproducibility, is to carefully document the intent and procedure that were used to create the augmented ENDF/BVIII. 0 covariance library for SCALE 6.3 such that the users of SCALE are clearly informed about how the ENDF/B-VIII.0 covariance library was augmented.