LONDON The threat of a radiation leak at a Japanese nuclear power plant reopened the debate on Friday over nuclear safety, with industry experts convinced by the efficiency of new security and green groups fearing disaster.
An earthquake, which hit Japan's northeastern coast and is expected to have killed at least 1,000 people, knocked out the cooling system from one reactor and Tokyo said there could be a small leak.
Thousands of residents were evacuated from the immediate area of the Fukushima plant, about 240 km (150 miles) north of Tokyo.
Industry experts said the precautions taken at Fukushima showed that enhanced security at nuclear power plants should prevent any disaster. But green groups said the threatened leak showed that the risks were still too high.
"I wouldn't expect there to be a radiation emergency ultimately, they may have something to fix but it's a precaution more than anything else," said Sue Ion, former chief technology officer at British Nuclear Fuels, after Japan declared an atomic power emergency.
Altogether, some 11 reactors shut down after the earthquake.
The risk to the Fukushima facility centred on the failure of a cooling facility which had led to a build up of pressure within the reactor core.
Successive layers of security within the plant should prevent any leak of radiation, said Jeremy Gordon, an analyst at the World Nuclear Association based in London.
The nuclear power industry has talked of a renaissance after disasters in the 1970s and 1980s, at Three Mile Island in eastern United States and Chernobyl in Ukraine, crippled its reputation for decades among the general public.
New interest follows the development of more advanced plants, and a new focus on security of supply and carbon emissions. Nuclear plants generate constant, low-carbon power, in contrast to wind and fossil fuels respectively.
"The reactor designs that are up for consideration today are generation three where the safety systems operate at an even higher level," said WNA analyst, Jonathan Cobb.
But environmental groups said the threat of a radiation leak underscored the general risks from atomic energy.
"We've opposed nuclear power for decades, and this is another proof that it can't be safe," said Sven Teske, director of renewable energy at Greenpeace International.
A leading U.S. scientist group said the incident highlighted the grave risk of inadequate back-up power to cooling systems at U.S. facilities.
The Vienna-based International Atomic Energy Agency (IAEA) estimated last month that about 10 countries have decided to introduce nuclear power and started preparatory infrastructure work, up from four in 2008.
Teske said the world could do without nuclear power and rely solely on low-carbon renewable energy.
"A mix of solar, wind, biomass, geothermal and hydropower is enough to supply every country. It's not a matter of technology but policy."
(Additional reporting by Daniel Fineren and Karolin Schaps; writing by Gerard Wynn, editing by Elizabeth Piper)