## 2 Overview of Microreactors
### Expectations and Challenges  
Microreactors can address energy needs with the advantage of rapid deployment and portability in remote or hard-to-reach areas. Unlike large nuclear power plants, they can be set up and start generating power within a short time, offering significant time and cost savings [228; 229; 229; 116; 161; 120; 121; 162; 163; 164; 165; 166; 167; 168; 169; 170; 171; 172; 173; 174; 175; 176; 177; 178; 179; 180; 181; 182; 183; 184; 185; 186; 187; 188; 189; 190; 191; 192; 193; 194; 195; 196; 197; 198; 199; 200; 201; 202; 203; 204; 205; 206; 207; 208; 209; 210; 211; 212; 213; 214; 215; 216; 217; 218; 219; 220; 221; 223]. Designed to fit standard containers, they can be easily transported using various means of transportation, although this process can present regulatory challenges [225; 229]. Economic analyses evaluate the advantages and costs of microreactors. The Nuclear Energy Institute has conducted cost assessments for microreactor facilities that require long-term operation and periodic refueling [228; 229; 225]. These analyses indicate a wide range of costs, influenced by capital expenditures, credit guarantees, and ownership types [161; 191; 207; 217]. Compared to diesel generators, microreactors stand out for their economic competitiveness. Diesel generators incur high capital costs and fuel requirements, making microreactors a more advantageous long-term option. In terms of electricity production costs, microreactors are generally more competitive [228; 229]. The small size and factory production capabilities of microreactors help reduce costs. As production volumes increase, capital and fuel costs are expected to decrease [229; 228; 229; 25]. Additionally, operational and maintenance costs may also decline. Costs vary depending on distribution conditions and microreactor designs. Ownership type and credit guaranteesalso impact capital costs. The compact size and portability of microreactors reduce setup time and costs, addressing some issues typical of mega projects [25; 29; 228; 229]. Despite the numerous advantages provided by microreactors, several challenges exist. One major challenge is the limited availability of HALEU fuel, essential for the effective operation of microreactors, but currently not available on a large scale [25; 29; 228; 229]. The safety and proliferation risks associated with microreactors can be higher compared to large nuclear power plants. These reactors require stringent implementation of safety standards. Proliferation risks involve concerns about the malicious use of nuclear materials. Therefore, to ensure the safety of microreactors, security measures and regulatory mechanisms that comply with international standards must be developed [25; 29; 228; 229]. Blockchain technology can be utilized to address these issues to some extent [230]. The successful deployment of microreactors heavily depends on the current state and future of nuclear fuels. Most microreactors use HALEU fuel. However, the production of HALEU fuel is currently limited, and commercial supply is not fully established. In the United States, the existing nuclear fuel cycle infrastructure is not suitable for providing new HALEU sources or producing the necessary qualified packaging for HALEU transportation. Therefore, commercial supply is unlikely to be realized until the microreactor market matures. The production of HALEU fuel involves various technical and logistical challenges. Technical challenges include achieving high enrichment levels and safely processing the fuel, while logistical challenges involve the safe transportation and storage of the fuel. To overcome these challenges, it is necessary to increase existing production capacities and establish new production facilities [228; 229]. Several strategies are being developed to increase HALEU production capacity in the future. These strategies include modernizing existing production facilities, establishing new facilities, and fostering international collaborations.