Definition
A nuclear reactor that produces more fissionable fuel than it consumes by converting non-fissionable material (such as uranium-238) into fissionable material (such as plutonium-239) during operation.
Plain English
A nuclear power source that creates more usable fuel than it burns, by turning otherwise unusable material into new fuel as it runs.
Context Anchor
Seen in discussions of nuclear power, experimental propulsion, and historical nuclear-powered aircraft concepts; it is not a normal cockpit operating term.
Derivation
From 'breed,' meaning to produce or generate offspring. The reactor is named for its ability to 'breed' new fuel from material that could not be used directly.
Why Pilots Care
For most pilots, this term has no direct flight-operating consequence. It matters mainly when reading about aviation history, advanced powerplant concepts, or nuclear-powered aircraft proposals.
Intuition Check
“Breeder” does not mean anything biological here. It means the reactor creates additional usable nuclear fuel while producing power.
Example Sentence 1
Early Cold War research explored whether a breeder reactor could power a long-endurance aircraft without refueling.
Example Sentence 2
The concept allows a reactor to create more usable fuel from material that would otherwise remain inert.