In order to achieve the challenging design goal of a future-advanced small modular reactor, this paper suggests newly three concepts for small modular reactor such as a fissile and fertile multiple arrangement, a molten-fueled salt coolant, and a self-adjustable pitch size. The multiple arrangements of fissile and fertile layers makes it possible to enhance breeding fissile isotopes through the optimal placement of the thinner fissile layer between the thicker fertile regions in the core. The second idea of a creative use of molten-fueled salt as a coolant decreases the fuel loading as well as promotes safety significantly even if a severe core accident happens such as the loss of coolant accident. In that case, the reactor maintains the subcritical state owing to loss of molten-fueled salt coolant that contributes loss of neutron source. When the fuel is melt down, it is smeared into coolant that incorporates the molten-fueled salt coolant and both fuel and coolant are circulated simultaneously like the typical molten salt breeder reactor. The third idea of the new small modular reactor is an automatic size change of fuel lattice pitch, which plays an important role on keeping reactivity swing within a specified limit. This self-adjustment of fuel rod and assembly pitch sizes can be realized by using of the shape memory material such as Ti-Ni alloy in the fuel assembly bottom grid. Simulation results of the Monte Carlo depletion calculations indicate that the proposed brand-new small modular reactor system is sufficiently achievable by providing an ultra-long fuel cycle length and a sufficiently low reactivity swing through the optimization of design parameters. Copyright (c) 2017 John Wiley & Sons, Ltd.