The Fast Flux Test Facility at the Hanford Site in Washington was a 400-megawatt-thermal fast-neutron research reactor built for testing, not power generation. Completed in 1978 and first operated in 1980, it served from 1982 to 1992 as a national center for commercial reactor research, especially breeder-reactor-related work, though it was not itself a breeder reactor. Using liquid sodium coolant, it tested advanced fuels, materials, components, operating practices, and safety designs. Deactivation began in 1993, paused and resumed amid plans for possible tritium production and legal disputes, and by 2005 draining its remaining sodium effectively made it unusable in its existing state. In 2006 it was designated a National Nuclear Historic Landmark.