AbstractThe neutronics and radiation shielding issues were assessed for the ARIES-RS power plant. The assessment addresses the breeding level, service lifetime, radiation damage, shielding requirements and design, and personnel protection. Major efforts were devoted to fulfil the top-level requirements which include the demonstration of a closed tritium fuel cycle, generation of no radioactive waste greater than Class C, and production of electricity at a competitive cost. The material optimization was one of the themes of this study as it influences the neutronics results and helps meet the requirements while minimizing cost. An important outcome of the neutronics and shielding analyses is the specification of the radial builds that contain key component parameters in terms of sizes and optimal compositions. The shielding system comprises a major element of the fusion power core (FPC). The primary function of the shield is radiation protection: protection of superconducting magnets, vacuum vessel, workers and the public. As an element of the power core, the bulk shield meets other requirements for power production and service lifetime. In addition, it serves as a heat sink for the FW/blanket decay heat during a loss-of-coolant accident. All shielding elements are integrated with the remainder of the FPC to meet the assembly, mechanical support and attachments, and maintenance requirements. The system requirements developed for the shield stem from these essential shielding functions. The work reported herein illustrates the strong impact of numerous factors (such as service lifetime, blanket segmentation, shield optimization, radial builds, and unit costs of materials) on the economics of power production.