at building smaller reactors, which are faster to realize, safer, and at lower cost for a single reactor. Despite the loss of scale advantages and considerably less power output, funding was expected to be easier thanks to the introduction of modular construction and projects with expected shorter timescales. The generic SMR proposal is to swap the economies of unit scale for the economies of unit mass production. Proponents claim that SMRs are less expensive due to the use of standardized modules that can be produced off-site. SMRs do, however, also have some economic disadvantages. Several studies suggest that the overall costs of SMRs are comparable with those of conventional large reactors. Moreover, extremely limited information about SMR modules transportation has been published. Critics say that modular building will only be cost-effective at high quantities of the same types, given the still remaining high costs for each SMR. A high market share is needed to obtain sufficient orders. Proponents say that nuclear energy with proven technology is safe; the nuclear industry contends that smaller size will make SMRs even safer than conventional plants. Critics say that more small reactors pose a higher risk, requiring more transportation of nuclear fuel and increased generation of waste. SMRs require new designs with new technology, the safety of which has yet to be proven. Until 2020, no truly modular SMRs had been built. In May 2020, the first prototype of a floating nuclear power plant with two 30 MWe reactors - the type KLT-40 - started operation in Pevek, Russia. This concept is based on the design of nuclear icebreakers. The operation of the first commercial land-based, 125 MWe demonstration reactor ACP100 (Linglong One) is due to start in China by the end of 2026. General aspects Licensing Once the first unit of a given design is licensed, licensing subsequent units should be drastically simpler, assuming that all units operate identically. Scalability A future power station using SMRs can begin with a single module and expand by adding modules as demand grows. This reduces startup costs associated with conventional designs. Some SMRs have a load-following design such that they can produce less electricity when demand is low. Siting/infrastructure SMRs will require much less land, e.g., the 470 MWe 3-loop Rolls-Royce SMR reactor takes , 10% of that needed for a traditional plant. This unit is too large to meet the definition of a small modular