[ttfkam]

Not only was a design ready to be built, it was built. Went online 39 years ago. Produced 1.2GWe at peak. Not only produced power on its own but reprocessed spent fuel from other nuclear reactors.

Decommissioned 28 years ago. Because it didn't work? No. Because it wasn't safe? No. Because it wasn't reliable? No, it had a 95% availability rate.

It was taken out of service due to political pressure and legal maneuvering, not technical reasons.

https://en.wikipedia.org/wiki/Superph%C3%A9nix

[natmaka]

Facts: Superphénix was a prototype. It didn't reach its goal (reaching the industrial stage). Not a single model of breeder reactor reached it. Mentioning its high availability rate neglects planned shutdowns (planning enough of them improves it). Its load factor in 1996 (just before its shutdown), more relevant, was 0.31, thus well below the minimum viable for an industrial reactor. Some people consider the project to be a success, but no expert or its operator has ever said so (they proclaimed their confidence in their ability to achieve industrial operation by an unspecified date), and its successor, named "ASTRID", launched 12 years later, which was supposed to design and build a reactor for €5 billion, spent more than €700 million on studies alone before being put on hold, so "it worked, but everything has to be redesigned...".