Flexible Conversion Ratio Fast Reactors

A group led by Professor Todreas and Dr. Hejzlar is developing within a DOE-sponsored project a flexible conversion ratio fast reactor system for time-dependent management of both fissile inventories and higher actinides. The focus of the design effort is on reactor core designs having two conversion ratios: (1) near zero to transmute legacy waste, and (2) near unity to operate in a sustainable closed cycle. Two liquid reactor coolant core candidates are selected for development and cross-comparison. The coolants are lead and liquid salt (as distinguished from molten salt containing molten fuel). Gas coolant core results from an ongoing MIT project and sodium results from Argonne National Laboratory work will be evaluated in comparison with the lead and liquid salt coolant core results. The feasibility of the lead-cooled reactor concept has been established for both conversion ratios, and the design of liquid salt-cooled cores is under development. The liquid salt-cooled concept was found to be more challenging to develop and required some innovative features to overcome neutronic and thermal hydraulic challenges. A patent application for the conceptual design of a liquid salt-cooled reactor that overcomes these challenges was submitted in June 2007.