What does early submarine steel cutting say about the reactor?

Could the early steel-cutting milestone refer to reactor components that must be prepared first?

Some components begin early, but a material-order date does not establish reactor assembly, and the lead-time estimate is explicitly approximate.

Early steel work can include material for components that will be needed much later. It does not mean that the reactor is already undergoing final assembly. A roughly four-year lead before installation is recalled for reactor work, with an explicit warning that the estimate is from memory. Ordering material, making components, and assembling them are separate stages when interpreting a construction date.