The SNR-300 was a fast breeder sodium-cooled nuclear reactor built near the town of Kalkar, North Rhine-Westphalia, Germany.
The site is now the location of a theme park, Wunderland Kalkar, which incorporates much of the power plant buildings into the scenery.
Superphénix, being a prototype reactor, demonstrated reliability issues and had a historical capacity factor of less than 14.4%.
In late 1972, Germany, Belgium and the Netherlands charged the Siemens subsidiary Interatom to build a fast breeder.
On 20 May 1975, the Council of the European Communities established the Joint Undertaking 'Schnell-Brüter- Kernkraftwerksgesellschaft mbH' (SBK).