The European Commission called for stress tests every six years on the dozens of nuclear reactors operating in the European Union as it issued new safety rules in the wake of Japan's Fukushima disaster.

"The proposed legislation transmitted to member states aims to 'Europeanise' nuclear safety," said the EU's Energy Commissioner Gunther Oettinger. "We hope it will not be rejected by the states."

The checks on 64 existing nuclear plants in the EU, to be carried out by "peer" teams of EU-wide inspectors rather than left to national experts, aim both to avoid a repeat of the 2011 Fukushima accident and to plan a response should a nuclear emergency occur.

If the proposal is agreed, the failure of a country to comply with safety recommendations issued after the stress tests would leave it open to judicial action and fines by Brussels.

"It's up to member states to decide if they want to produce nuclear energy or not. The fact remains that there are 132 nuclear reactors in operation in Europe today," Oettinger said.

"Our task at the Commission is to make sure that safety is given the utmost priority in every single one of them."

The rules will hopefully be approved in 2014 with member states given 18 months to write them into their own legislation.

Greenpeace however was critical of the new rules, saying they "do little to rule out a European Fukushima".

"The new periodic reviews only offer small improvement on the current 10-year ones and will only test parts of each plant periodically," Greenpeace added in a statement.

A total of 14 EU nations currently run nuclear plants, some with several reactors, and while Germany is shutting down its nuclear energy sector, Poland is planning to join the club.

Two-thirds of the reactors are located within 15 kilometres (nine miles) of towns of more than 100,000 people.

The new proposals also call for national reviews at least every 10 years and recommend that national regulators remain strictly independent from the nuclear industry, avoiding all conflict of interest.

A report in October said immediate safety upgrades costing billions of euros (dollars) were needed in nuclear power plants "nearly everywhere" in Europe.

EU "stress tests" ordered in the aftermath of Fukushima overall showed "satisfactory" safety, with no need for the immediate closure of a single reactor, the report said.

But saying many of the 132 reactors failed even to meet international safety standards, Oettinger confirmed at the time that bringing plants up to scratch could cost anywhere between 10 billion and 25 billion euros ($13 billion-$32 billion).

Last year's stress tests, also carried out in neighbouring Switzerland and Ukraine, aimed to establish whether plants could resist extreme natural disasters such as earthquakes and flooding, as well as airplane crashes.

They found that seismic instruments were either lacking or needed improvement in 121 reactors.