Best Estimate Plus Uncertainty (BEPU): Status and perspective

The Best Estimate Plus Uncertainty (BEPU) constitutes an approach, a procedure or a framework aimed at making feasible the application of nuclear Thermal-hydraulics to the licensing and the safety evaluation processes of Nuclear Power Plants (NPP). The features of BEPU are such to make attractive its use to address any design and operational issue in NPP technology. BEPU is also the tip of the iceberg of competence in nuclear thermal-hydraulics or a cross-way into the Thermal-hydraulics universe. The triggering idea for BEPU came from the adoption of Best Estimate system thermal-hydraulics (SYS TH) codes for accident analysis in water cooled nuclear reactors. The development of BEPU implies interactions between deterministic and probabilistic analyses also recognized as Deterministic Safety Assessment (DSA) and Probabilistic Safety Assessment (PSA). The present paper deals with an overview of BEPU features and applications including constitutive elements and of sample applications.