The manager of Fukushima Daiichi nuclear plant -- the site of the world's worst atomic disaster since Chernobyl in 1986 -- died on Tuesday (July 9) of oesophageal cancer, unrelated to his duties, it was announced by Tepco, the operator of the Fukushima station.

The nuclear plant, north of Tokyo was struck by a magnitude 9.0 quake and tsunami on March 11, 2011. Three reactors melted down and radiation forced tens of thousands of residents to evacuate the area near the plant.

Manager Masao Yoshida was widely credited with preventing the situation from spiralling out of control when he ignored an order from Tepco executives to stop pouring seawater over the reactors to keep them from overheating further.

He was one of a skeleton group of staff, known as the Fukushima 50, who remained at the plant at the height of the crisis, but he rarely spoke publicly about his experiences.

At the plant, the situation took a turn for the worse as radiation levels in groundwater soared, suggesting highly toxic materials from the plant are now close to the Pacific Ocean.

But Japan is forging ahead with attempts to restart idled reactors in the face of a sceptical public, after Fukushima highlighted weak oversight of the industry.

The country may restart several reactors shut down by the Fukushima crisis in about a year, a senior regulator said on Tuesday, a day after new safety rules went into effect designed to avoid a repeat of the disaster.

Getting units restarted is a key government goal to reduce the import bill for fossil fuel to run conventional stations. Only two of Japan's 50 reactors are connected to the grid and operators applied to restart 10 on Monday.

Presented by Adam Justice