Fission slows, and the reactor cannot run out of control.

At least their nuclear reactors can run for that long, supplying all the heat, light, fresh air, fresh water and power they need.

In contrast, American reactors run on "enriched" uranium, which is 2 or 3 percent uranium-235.

Since July 4, 2009 the reactor is not running.

The two reactors in Red Wing have run out of storage space and no place has been found to put the waste.

With heavy water, reactors can run on natural uranium.

The reactor would run on uranium enriched to 20 percent.

Some reactors run hot enough that the gas can directly power a gas turbine.

We are in open sea, there is no traffic about, and the reactor is running at a fraction of its total power.

The situation I've just described applies when the reactor is running with the focusing system switched off.