The integration of nuclear assessment (neutronics, shielding, and activation) is an essential element to the success of any fusion design and represents a major issue for power plant studies in particular. High fidelity in nuclear results mandates performing state-of-the-art nuclear analyses. This has been achieved in recent years through coupling the computer-aided-design system directly with three-dimensional neutronics codes to preserve all geometrically complex design elements and speed up feedback and iterations. This paper outlines several major nuclear issues addressed for the recently completed ARIES-ACT1 tokamak conceptual power plant study. An integral nuclear approach was deemed necessary to deliver an optimal design. This approach considered the overall configuration, design requirements (including tritium self-sufficiency), smart selection of low-activation material for all components, radial build optimization and definition, and safety and environmental concerns. This paper reports the main results of this integral approach that aims at considering several effects that influence the global behavior of a complex power plant such as ARIES-ACT1.