Design of a Decay Heat Removal System for EFIT Plant

The Integrated Project EUROTRANS, funded by the European Commission as part of the 6^th European framework program, provides the advanced design of a multi purpose research oriented Accelerator Driven System (ADS), called XT-ADS (eXperimenTal-ADS), and the preliminary design of an industrial scale ADS, called EFIT (European Facility for Industrial Transmutation) [1]. EFIT [2] [3] is fuelled with Minor Actinides (U-free fuel) and its main design options overcome the limits of previous ADS projects, particularly as concerns the economic aspects, maintaining meanwhile the high safety level, the high reliability and low investment risks. EFIT is endowed with three different systems to remove decay heat, this paper deals with the Decay Heat Removal System 2 (DHR2). DHR2 mainly consists of an isolation condenser (IC) connected to the secondary side of the Steam Generators (SGs). DHR2 is a passive safety system: system operation is based on condensation of the steam coming from the SG unit and gravity head injection of the condensate back to the SG inlet. The system has been designed to satisfy the following two requirements: • to evacuate the decay power maintaining acceptable values of the vessel and fuel temperature; • to avoid lead solidification also in the configuration of maximum efficiency.