How Molten Salt Reactors Work

The Salt

A mixture of lithium fluoride and thorium fluoride, heated to around 700°C. At this temperature, the salt is a clear liquid — the nuclear fuel is dissolved directly in the coolant. No solid fuel rods, no fuel assemblies, no risk of a meltdown in the traditional sense.

“The fuel is already liquid. A ‘meltdown’ is just normal operation.”

The Core

The molten salt flows through a graphite-moderated core. The graphite slows down neutrons to the right speed for the thorium fuel cycle. The reactor operates at atmospheric pressure — unlike conventional reactors that operate at 150 atmospheres.

The Freeze Plug

At the bottom of the reactor sits a plug of frozen salt, kept solid by active cooling. If power fails — for any reason — the plug melts, and the entire fuel inventory drains by gravity into a safe storage tank below. No operator action needed. No backup power needed. Physics handles it.

The Heat Exchanger

The hot salt transfers its heat to a secondary loop, which produces steam at around 550°C. This drives turbines to generate electricity — or the heat can be used directly for industrial processes like hydrogen production or desalination.

How It Compares