Small, modular reactors [1] have been the dream of nuclear energy for a long time. The technology was proven a long time ago with nuclear submarines which have an outstanding safety track record. What’s stopping them from entering full scale production is a horrible mix of regulatory red tape and political opposition. Chief among the issues is a regulatory framework which is not designed to certify mass-produced reactors.
No one wants to invest the capital to get a manufacturing plant up and running if regulators aren’t willing to allow completed reactors to be commissioned and begin producing energy at a rate that matches the manufacturing rate. The insistence on treating every nuclear site as a unique project subject to years of environmental surveys and extensive, bespoke planning makes modular reactor designs moot as a technology. This is why every reactor gets a new design: they have to go through the process anyway so they might as well try to max out the production they can achieve at that site.