Japan last went without nuclear power in May-June 2012 - the first shutdown since 1970 - a year after a massive earthquake and tsunami triggered reactor meltdowns and radiation leaks at the Fukushima facility. The country's nuclear reactors provided close to a third of the electricity to keep the $5 trillion economy going before the Fukushima disaster, and utilities have had to spend billions of dollars importing oil, gas and coal to make up for the shortfall.