The first test of its kind since the ones carried out at Oak Ridge, Tennessee in the 1960s, its purpose is to learn more about the safe operation of a future Molten Salt Reactor (MSR).
First developed in the United States in the 1950s and '60s, MSRs differ from conventional light-water nuclear reactors in a number of significant ways that make them potentially a safer and more efficient alternative. This is because, though a light-water reactor and an MSR work on the same principle of nuclear fission, they have a fundamentally different engineering design.
In a light water reactor, nuclear fuel is enriched uranium or plutonium set in zirconium-alloy-clad rods immersed in water. This water acts as both the moderator and the coolant for the reactor.