31. S-PRISM is a commercial implementation of the Integral Fast Reactor developed by Argonne National Laboratory between 1984 and 1994. 32. To maximize the rate at which fast reactors can be deployed, they can be operated in maximum breeding mode. 33. In pyrometallurgical fast reactors , the separated plutonium and uranium are contaminated by actinides and cannot be used for nuclear weapons. 34. A fast reactor uses no moderator, but relies on fission produced by unmoderated fast neutrons to sustain the chain reaction. 35. The concept is generally very similar to sodium-cooled fast reactor , and most liquid-metal reactors have used sodium instead of lead. 36. AERE opted to focus on a lead-cooled 2.5 GWe Molten Salt Fast Reactor ( MSFR ) concept using a chloride. 37. This became less urgent with reduced demand forecasts and increased uranium supplies, and commercial deployment of fast reactors was postponed. 38. To the extent that fuel is reprocessed on-site, as proposed for the Integral Fast Reactor , opportunities for diversion are further limited. 39. In 1962, it became the first fast reactor in the world to supply electricity to a national grid, proving the concept. 40. Liquid metal cooling is also used in most fast neutron reactors including fast breeder reactors such as the Integral Fast Reactor .
