Modern Light Water Nuclear Reactors of Generation III+ and Small Modular Reactors: Challenges and Solutions in the Field of Nuclear Fuel and Management

This paper discusses light water cooled reactors (LWR) Generation III+ and small modular reactors (SMR) from the perspective of nuclear fuel characteristics and reactivity control systems. Technological advancements in reactor design have led to improved safety, efficiency, and reliability, particularly through the introduction of passive safety systems and optimization of fuel cycles. Special attention is given to the types of nuclear fuel used in new-generation reactors, including standard UO2 fuel, MOX (mixed oxide fuel composed of plutonium and natural or depleted uranium), and HALEU (high-assay low-enriched uranium with ²³⁵U enrichment between 5% and 20%), along with an analysis of their technical advantages. The section on reactor management addresses the concepts of active and passive safety systems, as well as reactivity control strategies under normal and accident conditions. A comparative analysis of several leading reactor technologies (EPR, AP1000, VVER-1200, NuScale) provides insight into different technical solutions regarding safety systems and fuel cycle management. The paper concludes with an overview of key challenges and future perspectives, with a focus on safety aspects.