Garigliano was in 1964 the fourth BWR ever worldwide commercial operated, and had the second highest MW-capacity after Dresden Nuclear Power Plant unit 1.

Final shutdown was on 1 March 1982 and the plant was handed to the Italian nuclear decommissioning authority SOGIN on 1 November 1999.

[2] The plant was constructed between November 1, 1959 and January 1, 1963, by Società Elettronucleare Nazionale, taking only four years to build.

The remaining fuel rods were kept in storage in Deposito Avogadro and in 2011 were sent to La Hauge, France to be reprocessed also.In 1999, the property of the plant was transferred to SOGIN, which began to dismantle the plant: the decommissioning is set to end in 2026.

Once reached the brown field status in 2026, the sphere and part of the structure will become a museum, in context of industrial archeology.The radioactive waste will remain on-site until its removal for permanent storage, and the deposits will be demolished, returning the surrounding area to "green field status".

Because of the need to treat liquid waste produced during the dismantling, between 2014 and 2021 SOGIN built a new radwaste to replace the old one which was used during the plant's operating life.

[4] During the late 1960s, the burial of very low-level radioactive waste produced by the plant (such as contaminated protective clothing) was authorized.

[12] Some radioactive waste is being kept in steel drums outside the plant, waiting to be stored in the deposits.