The Molten Salt Reactor (MSR) is considered one of the most suitable technology for micro mobile reactors due to its low operating pressure (3 ~ 5 atmospheres), which reduces weight and volume compared to pressurized water reactors (PWRs). Unlike PWRs, MSRs use molten salt as both fuel and coolant, enabling compact and transportable designs. This study outlines the conceptual design of a micro mobile MSR and establishes safety criteria for transient states. It proposes strategies for managing the primary loop, intermediate heat transfer system, and air-cooled Balance of Plant (BOP) while addressing thermal and structural constraints, such as maximum temperatures and molten salt freezing points. Control approaches for reactor output and BOP systems are analyzed, highlighting fast response and adaptability to frequent power changes. The study also compares fixed-speed and variable-speed pump operations and provides a framework for operational modes, from high-temperature standby to transport-ready conditions. These findings offer a foundation for efficient, safe, and flexible MSR deployment.

Microreactors, a type of Small Modular Reactor (SMR) under 20 MWt, are being developed globally for use in remote areas, utilizing fourth-generation nuclear technology for enhanced safety. However, there are no established standards for their commercialization. This study reviews road transport regulations for microreactors and proposes necessary design loads and evaluation criteria for their transport. Transport concepts were identified through a review of overseas developments, with requirements derived for both accident and normal conditions. The study also presents an approach for evaluating transport stability based on land-based nuclear plant regulations, considering load conditions from drops and puncture impacts, as well as random vibrations during road transport. This work aims to support the design of mobile reactor transport systems and contribute to new regulatory and licensing procedures for advanced reactors.

The primary focus in the nuclear power market revolves around the advancement of small modular reactors (SMRs) featuring fourth-generation nuclear technology. Microreactors, a subset of SMRs, are characterized by their portability due to their very small size. Despite the accelerated development of microreactors, there are currently no regulations concerning their transportation. To pave the way for future regulatory requirements, existing laws and standards were initially examined. This included a review of basic standards, special conditions of the Road Traffic Act, road transport regulations for nuclear material shipments, and physical protection regulations. Additionally, summaries were provided for design standards related to acceleration loads and vibration tests during road transport and land-based nuclear power plant designs. The anticipated outcome of this study is comprehensive coverage of considerations for designing a transport system for micro-nuclear reactors, providing developers the flexibility to selectively apply them to their specific needs. Furthermore, it is anticipated that this information can serve as fundamental data for establishing licensing requirements in the future.