Noun
nuclear reactor in which nuclear fissions are caused by fast neutrons because little or no moderator is used
Source: WordNetDuring his visit, Iyengar was impressed by the plutonium-fueled pulsed fast reactor. Source: Internet
Since water is a moderator, it cannot be used as a coolant in a fast reactor. Source: Internet
The Russian Alfa class submarine uses a lead-bismuth-cooled fast reactor as its main power plant. Source: Internet