This paper briefly reviews the molten salt reactor (MSR) concept and explains the key technology innovations that have revived the very concept in the 2000s since the 1960s. The paper compares the origin of the molten-salt reactor concept and how the encouraging results of the aircraft reactor program led to the recognition of the potential of MSR for economical generation of electricity. The role of the MSR experiment was to demonstrate the practicality of this high temperature fluid-fuel concept which seemed so promising on the basis of materials compatibility information and calculated fuel cycle costs. This paper also describes and compares the reactors itself, including the fuel composition, diagram structure, moderators, materials, cost, efficiency, and layout. It further examines the safety hazards overcome in the advanced molten state reactors due to improvements in technology. A review is further extended to the key technology innovations in Transatomics Power’s (TAP) advanced MSR followed by the design pathway chosen instead of a thorium-fuelled reactor. It gives us a comparative analysis which concludes that the advanced MSR being used by TAP proves to be superior to other light water reactors (LWR) by significantly reducing waste. © TJPRC Pvt. Ltd.