Starting in 1970, this article studies how Chernobyl Nuclear Power Plant was built. It follows the station’s operational history until 1982. During that year, reactor block one suffered a torn reactor channel, four years prior to the well-known catastrophe of 1986. It uncovers the genesis of these accidents by analyzing everyday history at the construction site. Construction relied on long established tools and processes, tried out at large-scale and mostly non-nuclear development areas. Masons, carpenters, and welders dealt with planned quotas and deadlines, material and personnel shortages, as well as a lack of quality management. The tools they used to build this nuclear giant were rather a shock of the old (Edgerton) than futuristic.It uncovers circumstances, non-alignments, and decisions that amounted to a working environment characterized by a technocratic culture. This culture overemphasized the fulfillment of plans and quotas to the detriment of safety as should have been warranted by the nature of a nuclear reactor as specified in plans and regulations. By following the plant’s construction in its everyday struggles, this article shows characteristics of the working culture that evolved on-site and led to the accident of 1982. This innovative approach aids understanding of why and how the catastrophe of 1986 came about—beyond the two standard reasons established in the literature, namely a faulty reactor design and mistakes made by the operators.