The CEA Paris-Saclay center is one of nine centers belonging to the French Alternative Energies and Atomic Energy Commission (CEA).

The Saclay site, located 20 km south of Paris on the Saclay plateau, is much bigger and was chosen in part to be close to Université Paris-Sud (which today is part of Paris-Saclay University).

[7] The Saclay site was designed by the architect Auguste Perret.

The Osiris and Isis reactors (operated between 1965–2019[10]) inspired the design of Iraq's Osirak [fr] facility.

[11][12] Multiple bacterial species were discovered to thrive in those reactor cores during operation, and may have fed off hydrogen from radiolysis.