Design and performance analysis of 15MWth SCO2-cooled micro reactor

Abstract

Supercritical carbon dioxide (SCO₂)-cooled reactors leverage the drastic variations in thermophysical properties near the critical point to achieve high-density compressor operation and low-density reactor operation. This unique characteristic enables enhanced thermal efficiency at moderate reactor outlet temperature while improving the economic viability and operational safety. Furthermore, SCO₂-based turbomachinery (e.g., turbine and compressor) exhibits exceptional compactness, facilitating modular design and miniaturization potential. These combined advantages have positioned SCO₂-cooled reactor as a prominent research focus in nuclear engineering worldwide. This study presents the comprehensive design and performance evaluation of a 15MW_th SCO₂-cooled Micro Reactor (SCMR-15). The core configuration was optimized through multiphysics modeling, where thermal-hydraulic calculations determined fundamental dimensions, and Monte Carlo simulations using OpenMC code resolved neutronics characteristics and reactivity control mechanisms. Computational analyses demonstrated: (1) The control drum system provides sufficient shutdown margin, exceeding safety requirements; (2) Key performance metrics, including power peaking factor, fuel pellet maximum temperature, and cladding peak temperature, remain well below design thresholds; (3) Inherent safety features are ensured by consistently negative temperature reactivity coefficients and void coefficients.