A lead-cooled fast reactor system for TRU burning is developed, using TRU-U-Zr metallic alloy fuel. This core has a rated thermal power of 900 MWt (372 MWe). The design and analyses covered in this study include neutronics design, thermal-hydraulics analysis, thermal system design, system mechanical design and analysis, system arrangement, passive decay heat removal system evaluation and safety analysis for ATWS events. The gross and net thermal efficiencies are 44.5% and 41.3%. There are two pumps and eight steam generators and they are arranged to provide a proper room for work space in the top of the reactor head. The lead coolant mass in the reactor pool was estimated to be 7,465 ton and this caused the maximum stress of 125 MPa in the top portion of the containment vessel. But, this is below the currently established limit of 165 MPa. Design challenges inherent in the transmutation reactor due to large burnup reactivity swing and high fast neutron fluence are overcome by the introduction of boron carbide within the tie rods with axial cutbacks of 21.8 cm. The maximum coolant speed turns out to be 1.82 m/s and the maximum fuel temperature is only 703 °C in the rated full power condition. The long-term cooling behavior upon the concurrent occurrence of loss of heat sink and loss of flow, the hot pool temperature is maintained below the design limit of 650°C thanks to the improved decay heat removal design with heat transfer enhancement mechanisms. The analysis of ATWSs in the investigated core does not reveal any problem in the view point of fuel temperature, cladding temperature and hot pool temperature. In conclusion, the 900 MWt LFR system in this study does not pose any significant concern except for the seismic loading due to large coolant density and the verification of newly introduced design resolutions for a long-term decay heat removal.
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