Feasibility Studies and Scope Analyses for a SUPERSTAR Demonstrator Neutronics Design

A preliminary feasibility study and scope analysis for a demonstrator (demo) of the SUstainable Proliferation-resistance Enhanced Refined Secure Transportable Autonomous Reactor (SUPERSTAR) has been performed. Preliminary core design studies have been carried out focused on maximizing the power level compatibly with natural circulation cooling and transportability requirements, while meeting the foremost goals of (i) providing energy security and proliferation resistance thanks to a long life core design, (ii) minimizing the reactivity swing over the fuel lifetime, and (iii) flattening the radial power profiles, as demanded by the choice of wrapper-less fuel assemblies and by the stringent technological constraints imposed by the short-time-to-deployment feature. Once established appropriate geometrical pin and fuel assembly specifications, a suitable active height allowing the system to be cooled by free-flowing lead has finally been set through parametric T/H analyses. Fuel cycle calculations have been then performed to optimize both the fresh fuel composition and the radial enrichment zoning. Moreover, the use of several absorbing materials has been investigated in order to guarantee enhanced safety by incorporating control elements having a net density greater than that of the surrounding lead coolant. A complete static neutronic characterization of the resulting core has been finally accomplished.