Bulletin of the Atomic Scientists: After years of investment, South Africa has abandoned its plan to develop a fleet of electricity-generating pebble bed modular reactors (PBMR), once hyped as the future of nuclear power.Problems with the PBMR aren’t new; a 2008 German report chronicles Germany’s own problems developing the reactor since 1967.China, the only other country still developing PBMR-based power reactor designs, has taken a slower approach, and it is unclear if they have run into problems as well.