A view on identification of thermal-hydraulic phenomena for validation of best-estimate computer codes

Validation of best-estimate codes is a necessary step to prove their applicability to calculate accident scenarios, including the course of events. It shall demonstrate that those physical phenomena, which are important for a scenario, are calculated appropriately. A common list of 113 thermal-hydraulic phenomena is provided, based on previous reports of OECD/NEA-CSNI and IAEA, including Separate Effects Test (SET) facilities and Integral Test facilities of PWRs and BWRs, VVERs, Advanced Reactors, as well as Containment. Added objective of the activity is to show that the list of phenomena is applicable to the major number of water-cooled reactors. Twelve reactor types are considered for the characterization of 47 accident scenarios cross-linked with the identified phenomena. Focus of this paper is on the updated identification of the list of thermal-hydraulic phenomena.