Another Japan Reactor Shuts Down; Only One Left Another Japanese nuclear reactor has been taken off line for maintenance, leaving the country with only one of its 54 reactors operational following last year's devastating earthquake and tsunami. The last reactor is expected to be shut down by early May, raising the possibility of power shortages across the nation as demand increases in the hot summer months. 6 reactor at the Kashiwazaki-Kariwa complex was taken off line early Monday by the Tokyo Electric Power Co. The utility also runs the plant in Fukushima, northeast of Tokyo, that suffered meltdowns, explosions and radiation leaks after the March 11 quake and tsunami.