What does the "M" in SMR (small modular reactor) stand for?

The "M" in SMR stands for Modular, describing reactors built from standardized components in a factory and then shipped to a site for assembly, rather than custom-engineered on location piece by piece, an approach meant to cut both the enormous cost and the decade-long construction timelines of traditional nuclear plants.

Magnetic has no connection to this term; magnetic confinement is actually a concept from nuclear fusion research, an entirely different technology from the fission reactors SMRs use. Manual would describe the opposite of what SMRs aim for, since the entire point is standardized factory production, not hands-on custom manual assembly.

Companies like NuScale have already won regulatory approval in the US for their small modular reactor designs, but as of now very few commercial units have actually been built and connected to a grid, so the real-world cost and speed advantages are still being proven.