Japan's Hitachi said Thursday it would more than double its nuclear power business within a decade owing to growing overseas demand and post-disaster work at the crippled Fukushima atomic plant.

The industrial group said the unit's annual sales would reach 360 billion yen ($4.5 billion) in the fiscal year to March 2021, compared with 160 billion yen for its latest fiscal year ended in March.

"Nuclear power is effective energy for a reduction of (carbon dioxide emissions), and the company plans to promote it ... on continued demand worldwide," Hitachi said in its mid-term business plan released Thursday.

The company, which makes everything from microchips to railways, added that it would develop technologies for next-generation nuclear power plants with higher safety standards.

Some growth in the atomic power business would come from decades-long decommisioning operations at the Fukushima Daiichi plant, where reactors were sent into meltdown after being swamped by last year's quake-sparked tsunami.

Japan has switched off its nuclear reactors in the wake of the crisis, using more expensive fossil-fuel alternatives to make up some of the shortfall.

Radiation from Fukushima, in northeastern Japan, was scattered over a large area and spread as far as several hundred kilometres from the power station by wind and rain.

Tens of thousands of people were evacuated from their homes around the plant and swathes of the area remain badly polluted.