“…The fuel element in an HTGR reactor can be cylindrical, such as in the Dragon reactor 29 ; spherical, such as in the AVR, Xe-100, and HTR-PM reactors [30][31][32][33][34] ; or block-type, as is the case with the AHTR reactor. 22 According to the literature review, studies comparing the use of thorium-based fuel with various driver materials in HTGRs have often been conducted in prismatic block-type HTRs because of the flexible core that can support a wide range of fuel cycles. [35][36][37] Studies for PBR, on the other hand, have been conducted separately, and ThO 2 + UO 2 or ThO 2 + PuO 2 fuels have been widely used.…”