Twelve Xe-100 units of 80 MW each, in three groups of four, are envisaged if the project reaches a final investment decision, per the companies.
Phasing-in took place at 20% power at 20:41 on October 15, two days later than planned after a fault in non-nuclear voltage measurement circuits.
EDF placed the order in 2019; six further replacement steam generators are under manufacture at MHI's Kobe works for delivery from 2028.
First criticality is targeted for 2027, and the reactor will need 72 to 75 batches of fuel salt to reach it.
The plant at Pątnów would have 1,800 MWe of capacity and be built on the site of an existing coal plant.
The orders cover the CA02, CA03, CA05 and CA20 module scopes for the first AP1000 unit at Lubiatowo-Kopalino.
Fuel loading is targeted within the year, the China News Service reported, with first concrete poured in July 2021 for a 58-month build.