Core design investigation for a SUPERSTAR small modular lead-cooled fast reactor demonstrator

In this paper a preconceptual neutronics design study for a SUstainable Proliferation-resistance Enhanced Refined Secure Transportable Autonomous Reactor (SUPERSTAR) demonstrator is presented. The main goal of achieving the highest realistic power level limited by natural circulation and transportability, while providing energy security and proliferation resistance thanks to a long core lifetime design has been satisfactorily attained. A preliminary core configuration has been developed meeting the foremost requirements of limiting the reactivity swing over the core lifetime to about 1 $ and flattening the radial power profiles, as demanded by the choice of wrapper-less (i.e. without flow ducts) fuel assemblies and by the stringent technological constraints imposed by the requirement of short-term deployment. Reactivity coefficients and kinetic parameters have been evaluated for the reference beginning-of-life, middle-of-life and end-of-life core configurations. Furthermore, the results of thermal-hydraulic analyses of the primary loop have confirmed that the system can be effectively cooled by natural circulation heat transport, all the technological constraints being respected even when incorporating peaking factors.

► SUPERSTAR is a pool-type small modular LFR for international or remote deployment. ► Maximization of the economic performance of a natural circulation transportable LFR. ► Requirements of energy security, proliferation resistance and short-term deployment. ► Design focus: long-life core, reactivity swing minimization, flat power distribution. ► Neutronics performance goals suitably achieved, technological constraints respected.