Lead-cooled fast reactor

The lead-cooled fast reactor is a nuclear reactor design that uses molten lead or lead-bismuth eutectic as its coolant. These materials can be used as the primary coolant because they have low neutron absorption and relatively low melting points. Neutrons are slowed less by interaction with these heavy nuclei (thus not being neutron moderators) so these reactors operate with fast neutrons.

The concept is generally similar to sodium-cooled fast reactors, and most liquid-metal fast reactors have used sodium instead of lead. Few lead-cooled reactors have been constructed, except for the Soviet submarine K-27 and the seven Soviet Alfa-class submarines (though these were beryllium-moderated intermediate energy reactors rather than fast reactors). Some proposed new nuclear reactor designs are lead-cooled.

Fuel designs being explored for this reactor scheme include fertile uranium as a metal, metal oxide or metal nitride.

The lead-cooled reactor design has been proposed as a generation IV reactor. Plans for future implementation of this type of reactor include modular arrangements rated at 300 to 400 MWe, and a large monolithic plant rated at 1,200 MWe.