How is reactor safety actually engineered?

Reactor safety is built on defense-in-depth: multiple independent barriers so no single failure can cause disaster — robust fuel, a sealed vessel, a containment building, and redundant cooling. Modern designs go further with inherent and passive safety: cores that naturally slow down as they heat up, and cooling driven by gravity alone, no pumps or power required.

The result is one of the safest forms of energy production ever measured, per unit of electricity. Every hard lesson since the 1961 SL-1 accident has been absorbed into a deep engineering culture — and newer reactors are safer still.