Out of a total of 32 concepts gathered, among them 28 meet the Generation IV requirement of fission based self sustained criticality. Based on the primary design features , six "Concept Sets" are defined as: Liquid Core Reactors, Gas Core Reactors, Non-Conventional Coolant Reactors, Non-Convection Cooled Reactors, Direct Energy Conversion Reactors, and Modular Deployable Reactors. Non-Classical reactor concepts feature higher potential to meet or exceed Gen IV performance goals at somewhat lower technology readiness level. Despite many technology gaps and data uncertainties, there is no lack of innovation and revolutionary ideas in Non-Classical reactor concepts. Several concepts such as gas/vapor core reactors offer promising advances toward the Gen IV goals for sustainability, safety, and economy, and have potential for making significant inroads toward achieving the optimum utilization of nuclear energy. Gas/vapor core reactors set the upper performance potential in sustainability and safety with no insurmountable technology challenge. Evaluations of modular deployable concepts are underway. Direct energy conversion and non-convective cooled nuclear reactor systems are eliminated from further evaluation process.