Hundreds of problems have been found at European nuclear plants that would cost 25bn euros (£20bn) to fix, says a leaked draft report, according to BBC News.
The report, commissioned after Japan’s Fukushima nuclear disaster, aimed to see how Europe’s nuclear power stations would cope during extreme emergencies.
The draft says nearly all the EU’s 143 nuclear plants need improving. Anti-nuclear groups say the report’s warnings do not go far enough.
For its part, the regulatory body for European nuclear safety has urged the Commission not to use language that could undermine public confidence.
The report – the wording of which could change before its final version is published – points out that in the EU, 47 nuclear power plants with 111 reactors have more than 100,000 inhabitants living within a circle of 30km.
Four reactors in two unnamed countries would have less than an hour to restore safety functions if electrical power was lost, it adds.
In France, Europe’s largest nuclear power producer which relies on 58 nuclear reactors for 80% of its electricity, specific failings were found in all 58 nuclear reactors.
Earlier this month, a blast of escaping steam burned two people at the Fessenheim power station in eastern France – one of the country’s oldest nuclear reactors which has long been the target of regular anti-nuclear protests.
While the stress tests found deficiencies in many of Europe’s nuclear reactors, campaigners say they failed to address risks in crucial areas, such as ageing technology, terrorist attacks or human error.
As of June, all 143 nuclear plants in the EU were to be re-assessed using criteria covering both natural and man-made hazards.
Some governments have reappraised their nuclear energy strategy in the aftermath of last year’s Fukushima disaster, with Germany deciding to abandon nuclear energy for green technology and cleaner gas- and coal-powered plants by 2022.
Others, like France, have boosted investment in nuclear power since the meltdown.
The Fukushima Daiichi nuclear plant’s cooling systems were knocked out by the 11 March 2011 earthquake and tsunami in Japan. The disaster caused a meltdown at three of the reactors.