I've been looking to finish my fusion reactor and ran across a year-old post from Vermilion. I was wondering if this was correct with the new build.

"What?? What are you guys even talking about?
Radiation Shielding can be bought from Polaris Industrial Factories in bulk. Specifically Non-Linear Productions factories and Thermal Interactions Inc factories (planet). The factories will spawn within 1km of a Polaris Trade Station.
The planetary factories can also be found in Trader and Farr space.
Radiation shielding can also be occasionally found in the Abandoned Factory; Looted from Zirax Electronic Factories; Looted from the Engineering section of the Zirax Sector Command.

Reactor Cores can be found rarely in Ultra Rare loot containers; Bought from Electronics Factories (same deal as the Industrial Factories), Bought from Non-Linear Productions as well as the radiation shielding, and one can be found in the Engineering section of the Zirax Sector Command.

Most other parts used in Fusion Reactors can be bought from any of the industrial factories.
Solar Cells can be bought from M.A Corp Advanced; Superconductors from QuantumSTAR; Heat Exchangers from Imperial Arms in small amounts for a high price in the event you can't find a factory."