Antarctica is often cast as a last wilderness, untouched by humans and set aside for peace and science. Yet it also has a nuclear past that foreshadowed a shift in human interactions with the continent, away from development and towards protection. This paper examines the discourse around the installation and the dismantlement of PM-3A, the first and only large-scale nuclear reactor to have been used on the Antarctic continent. Affectionately known as “Nukey Poo,” the reactor was greeted with optimism by the USA and was seen as a catalyst for a more comfortable and technologically advanced future for the humans at McMurdo Station. This techno-optimism spurred visions of a resource-rich Antarctic future. When it became apparent a decade on that the reactor was too costly and had been leaking, the narration shifted to centre on environmental protection, resulting in the removal of a mountainside of gravel in the name of ecological restoration. The reactor is gone, but not forgotten – the site is designated as a Historic Site and Monument under the Antarctic Treaty System. Spanning from the Cold War to the Madrid Protocol era, the story of Nukey Poo provides a useful lens through which to track the evolution of attitudes towards Antarctica and to reflect on imagined Antarctic futures.