21. It operated as the Integral Fast Reactor prototype. 22. Fast reactor control cannot depend solely on Doppler broadening or on negative void coefficient from a moderator.23. One such proposal calls for a gas-cooled fast reactor that is fueled primarily by plutonium and americium. 24. Fast reactors lack a moderator, and thus lack one of the systems that remove neutrons from the system.25. Some SMRs are " fast reactors " they don t use moderators to slow down the neutrons. 26. Another proposed fast reactor is a fast molten salt reactor, in which the molten salt's moderating properties are insignificant. 27. Another proposed fast reactor is a Molten Salt Reactor, one in which the molten salt's moderating properties are insignificant. 28. A number of reactor designs, like the Integral Fast Reactor , have been designed for this rather different fuel cycle. 29. The GFR base design is a fast reactor , but in other ways similar to a high temperature gas-cooled reactor. 30. The plan is similar to that used following the closure of the Dounreay Fast Reactor in the United Kingdom.
