The BEPU process focusing on Accident Analysis and Chapter 15 of FSAR (NOTE: Acronyms and symbols in the figure not defined in the paper are, in alphabetic order: ITF = Integral Test Facility; SETF = Separate Effect Test Facility; SYS TH = System Thermal-Hydraulics; V & V = Verification and Validation; Ṁ_ECC = Mass flow-rate of injected Emergency Core Cooling; Ṁ_w,COND = Condensed mass flow-rate penetrating the core; Ṁ_S,G = Upward mass flow-rate of steam and gas; T_sat = saturation temperature; T_w = water temperature).