From your link,
> TerraPower must still complete construction, submit an operating license application, and satisfy all applicable safety and regulatory requirements before loading fuel and beginning operations.
I mean that doesn't sound like very big hurdles. It is an inspection of a completed reactor to make sure it wasn't managed and built like trash. Every factory and business and powerplant is subject to an inspection before it can operate. Even most residentual homes require an inspection before people can live in it.
Basically the built plant must pass a rigorous inspection before starting operations. But for that the plant needs to be built!