"Microreactors are very small, factory fabricated, transportable reactors which could provide power and heat for decentralised generation in civilian, industrial and defence energy sectors. The DOE Microreactor Program, led by Idaho National Laboratory (INL), is carrying out fundamental and applied R&D to reduce the risks associated with new technology performance and manufacturing readiness of microreactors.

The MARVEL design is primarily based on existing technology and will be built using off-the-shelf components allowing for faster construction, DOE has said. It will encompass a 100 kW thermal fission reactor, based on the SNAP-10A design which was developed in the 1960s as a 45 kWt thermal nuclear fission reactor for use in space missions. The sodium-cooled reactor, with natural circulation cooling, will have an operating temperature of 500-550°C and will be fuelled by high-assay low-enriched uranium from available research materials. It will use Stirling engines to transfer energy from the core to make electricity.

DOE said the reactor, which will be built inside the Transient Reactor Test facility (TREAT) at INL, could be installed in less than a year."