An in-depth analysis of the state of Japan's switched-off nuclear power stations showed a large percentage of them would not be able to go online again, Reuters news agency reported Wednesday.

A study compiled on the basis of interviews with experts and input from nuclear operators suggested that as few as a third and at most two thirds of the existing reactors would pass the new stringent safety checks and clear seismological and political hurdles in place after the Fukushima disaster three years ago.

The Reuters survey concluded the world's third-largest economy would remain heavily dependent on imported fuel, straining a trade balance that had been in the red for nearly two years.

Energy mix conundrum

The study expected nuclear energy in the country to eventually account for only some 10 percent of overall power supply, compared with the 30 percent the sector logged by virtue of the 54 nuclear reactors in operation before the tsunami and nuclear disasters.

Reuters said a number of stations at the low end of its calculations could make it impossible to reinstate nuclear as a base-load power source to feed a constant minimum to the national grid.

And because of a much bigger use of fossil fuels, Tokyo looked set to find it much harder to meet targets for reducing greenhouse gas emissions, the survey noted.

hg/hc (Reuters, AP)