Small modular reactors (SMRs) are a type of nuclear fission reactor which are smaller than conventional reactors. This allows them to be manufactured at a plant and brought to a site to be assembled. Modular reactors allow for less on-site construction, increased containment efficiency, and enhanced safety due to passive safety features. SMRs have been proposed as a way to bypass financial and safety barriers that have plagued conventional nuclear reactors.
Thorium is more abundant in nature than uranium. It is fertile rather than fissile, and can only be used as a fuel in conjunction with a fissile material such as recycled plutonium. Thorium fuels can breed fissile uranium-233 to be used in various kinds of nuclear reactors. Molten salt reactors are well suited to thorium fuel, as normal fuel fabrication is avoided.