[grecy]

China are currently building 27 fission reactors, and the construction time is 7 years.

If it takes 7 years to build something that is known and has been done a couple of hundred times before, I think it's safe to say it will take more than 4 years to build something of similar complexity that has never been done before.

[peutetre]

Helion's reactors are smaller and simpler. They've already built 6 prototypes across the last 11 years. They're building the seventh prototype now.