A recent American “mini-series” on Chernobyl, widely watched across the world, presented viewers with the concluding finding that this massive accident had occurred because the reactor design had inherent flaws; flaws that were known but not previously fixed because it was “cheaper” that way. The reactor design in question is the RBMK, and this paper will argue that this design was far from “cheap,” neither then nor now, and that its adoption as the second standard design for the Soviet Union’s nuclear power reactor fleet was based on much more than economic considerations. With the benefit of hindsight, it is easy to forget that reactor designs are always chosen for a multitude of reasons and never solely based on their technical or economic merits. Based on archival research, interviews, and industry publications, I show that approving and building RBMK reactors made good sense at the time, despite later claims to the contrary. Then I take the examples of a small modular reactor (SMR), the proposed NuScale Power Module, and a fast neutron reactor, TerraPower’s proposed Traveling Wave Reactor, to argue that we witness comparable negotiations today, as new designs for reactors (1) attempt to fit into existing safety and regulatory frameworks, (2) navigate security and nonproliferation concerns, and (3) embody visions of a specific sociotechnical order. I conclude that technical designs never occur in a socioeconomic, political, or cultural vacuum; instead, they are developed by people steeped in social norms, regulatory concerns, and economic expectations of a specific time and place. In the spirit of making this point relevant to practitioners, I will suggest ways of making these implicit frameworks visible, to actively and consciously start tweaking them, while staying aware of the implications that technical choices may have on our social expectations and vice versa.