Google AI says:
1. What Criticality Actually Is
- A Balanced State: A reactor is "critical" when each fission event releases enough neutrons to cause exactly one additional fission. It is not a runaway process, but a stable one where neutron production equals neutron loss (via absorption or leakage).
- Finite Power Levels: Criticality simply means the reactor is producing a constant power level (like idling an engine). It does not mean it can produce an infinite amount of power, only that the power is steady.
2. Why it is NOT Infinite Energy
- Fuel Depletion (The Finite Resource): Fission converts a very small amount of matter into a tremendous amount of energy, but the fuel (uranium-235) is consumed. Once the fissionable material has "burned up," the reaction stops.