Thermal-hydraulics analyses of ELSY lead fast reactor with open square core option

Among the next generation of nuclear reactors, well-known as Gen-IV, the LFR (Lead Fast Reactor) is one of the most promising advanced reactor able to comply the principles of sustainability, economics, safety and proliferation resistance. The ELSY project (European Lead-cooled SYstem), funded by the 6th European Framework Programme, aims at investigating the technical/economical feasibility of a high power lead fast reactor with waste transmutation capability.Several innovative design solutions have been proposed at system level and some of them regard the core region with open-assemblies that represents the reference option. To support the design phase and the safety assessment of ELSY, the thermal-hydraulic code RELAP5, modified to treat heavy liquid metals, has been taken into account.The paper deals with the development of the ELSY thermal-hydraulic and point kinetic model for RELAP5 focusing the attention at core assembly level to verify that the temperatures at nominal power conditions stay within the safety limits both in Beginning-of-Cycle (BOC) and in End-of-Cycle (EOC) conditions. Moreover, in order to have a first evaluation of the system behavior in accidental conditions, an Unprotected Loss-of-Flow Accident (ULOF) simulation at BOC has been analysed and discussed.List of acronymsADSAccelerator Driven SystemBOCBeginning-of-CycleDECDesign Extension ConditionEFITEuropean Facility for Industrial TransmutationELSYEuropean Lead-cooled SYstemEOCEnd-of-CycleFAFuel AssemblyFP66th Framework ProgrammeGen-IVGeneration IV (four)GESAGepulste ElektronenStrahlanlage (Pulsed Electron Beam Facility)HXHeat eXchangerICIsolation CondenserLFRLead Fast ReactorLMFRLiquid Metal Fast ReactorPDS-XADSPreliminary Design Studies on eXperimental ADSRVACSReactor Vessel Air Cooling SystemULOFUnprotected Loss-of-FlowW-DHRWater Decay Heat Removal