The planning and the progress to date of the United Kingdom’s first full-scale decommissioning project, which is dismantling the Windscale Advanced Gas-Cooled Reactor to stage 3 (the “greenfield” site concept), are described. The plant and the facilities that are being constructed to dismantle it are described. Methods used to separate and pack for disposal nonradioactive, low-level, and intermediate-level radioactive waste are summarized.