Final report of the covariance data utilization and promotion WG in the JENDL committee

Covariance Data Utilization and Promotion Working Group, JENDL Committee

The Covariance Data Utilization and Promotion Working Group organized in the JENDL committee has worked for three years to study the following five issues: (1) to identify uncertainties which have not yet been quantified or which are too difficult to be quantified, (2) to identify uncertainties which have been quantified, but whose reasonable bases are too weak, (3) to propose realistic methods to assure the reliability of the covariance data, (4) to propose actions which should be taken in the fields of nuclear data measurement, evaluation and application to promote the covariance data utilization, and (5) to make a recommendation how the covariance data are treated and positioned in Japanese evaluated nuclear data library, JENDL. This final report summarizes the outcomes of this working group. This report is organized as follows. First, the fundamental information/issues on the nuclear data uncertainties are briefly described, and then the current status and issues of the covariance data evaluation and utilization in the fields of the nuclear data measurement, evaluation and application are presented. Furthermore, several methods to assure the reliability of the covariance data are proposed, and finally, some guidelines such that what kind of covariance data provided in the evaluated nuclear data files are desirable, and what kinds of attention the users should take care in utilizing the covariance data are proposed as a conclusion of the working group.