A man works at the reactor core of a former nuclear power station at the amusement park 'Wunderland Kalkar' (Wonderland Kalkar) in the western city of Kalkar June 20, 2011. Wunderland Kalkar was a nuclear fast breeder, which was completed but never taken online, and in 1995 Dutch investor Hennie van der Most bought it and transformed into an amusement park attracting some 600,000 visitors per year. REUTERS/Ina Fassbender (GERMANY - Tags: SOCIETY)