Japan's Kashiwazaki-Kariwa nuclear power plan
Japan's Kashiwazaki-Kariwa nuclear power planReuters

On Monday, Japan's Tokyo Electric Power Company took its No. 6 reactor at the Kashiwazaki-Kariwa nuclear plant off line for maintenance, leaving only one more left to go, out of 54 nuclear reactors that once powered a third of Japan's electrical grid.

The last one, located on the northern island of Hokkaido, is scheduled for shutdown in early May, creating a possible power shortage for the summer months ahead.

The company suffered a major setback when its Fukushima nuclear complex northeast of Tokyo was damaged in the massive 9.0-magnitude earthquake and tsunami that struck the region on March 11, 2011.

The dangers of nuclear energy are still fiercely debated in the wake of the nuclear disaster in which three of Fukushima's six reactors went into partial meltdown.

Radiation leaked into the air, soil and water, with contamination samples discovered as far away as Las Vegas and Boston.

Moreover, none of the other Japanese reactors that are normally shut down for regular checks have been allowed to restart due to concerns about nuclear safety following the disaster, and any that were already shut down, stayed offline.

Until last year, one-third of Japan's electricity was produced by nuclear power plants. But it is not clear when or if any of the reactors will be restarted, and meanwhile Japanese firms have been urged to conserve energy.

The country has temporarily taken a step backward in time, returning to the use of coal and crude oil for production of electricity as the government works to formulate a new energy plan.