Small modular reactors (SMRs) are an experimental type of nuclear fission technology that differ from conventional nuclear reactors. SMRs are smaller and could potentially be factory-built and assembled on-site to provide power for smaller communities or industrial facilities.

In En-ROADS, the best way to model widespread adoption of SMRs is by using the New Zero-Carbon slider. This allows you to set the breakthrough year, commercialization timeline, and initial cost relative to coal. Because SMRs may differ from traditional nuclear power in terms of cost, social acceptance, and political dynamics, this slider lets you explore their impact independently from the Nuclear slider, which represents large-scale, conventional uranium-based nuclear fission.

You can further customize the timeline for SMR development and commercialization, as well as the progress ratio, under Simulation > Assumptions, within the Energy category.

Note that the New Zero-Carbon slider can be used to simulate any emerging clean energy technology that is not yet widely deployed, including, but not limited to, SMRs, nuclear fusion, or thorium-based nuclear fission.