A Nuclear Microreactor Nears Reality

ASME’s article presents MARVEL, a 100-kW-thermal microreactor built at Idaho National Laboratory with Department of Energy funding, as a pragmatic take on reactor design that leans on proven technology and the existing supply chain. It is a non-pressurised design with a sodium-potassium liquid-metal coolant that does not vaporise like water and cuts the number of auxiliary and safety systems to qualify. The uranium-zirconium hydride fuel, made by TRIGA International and used in research reactors for over 60 years, has a negative temperature coefficient that shuts its own chain reaction down if it overheats. Electricity is generated by off-the-shelf Stirling engines instead of steam turbines. Before construction begins the team plans to submit a Preliminary Documented Safety Analysis.

For component and certification-service suppliers the project points to a trend: modular microreactors with faster development cycles (the team is aiming for criticality within one to two years) and lower complexity than traditional light-water reactors. A useful case study for anyone in the ASME-compliant supply chain for small-scale nuclear components and for alternative power-conversion systems.