Cocooned Hanford F Reactor

The plutonium for the Trinity device, tested at Los Alamos in New Mexico, and the Fat Man bomb, later dropped on Nagasaki, Japan, was created in the B, D and F reactors. F Reactor is the third Hanford plutonium production reactor to be placed in interim safe storage - called cocooning - by the Bechtel Hanford-led Environmental Restoration Project team. Cocooning involves demolishing the reactor building down to the three-foot-thick concrete shield walls surrounding the reactor core. All openings in the remaining structure are sealed and a new roof is installed.