* Fukushima disaster prompted global nuclear rethink
* IAEA seeks strengthened action to prevent any repeat
* Proposes expansion of international safety checks
By Fredrik Dahl
VIENNA, Aug 15 (Reuters) - The U.N. atomic agency would carry out international safety checks of ten percent of the world's reactor units over a three-year period, under a draft action plan to prevent any repeat of Japan's nuclear crisis.
The document from the International Atomic Energy Agency (IAEA), obtained by Reuters on Monday, outlined a series of measures in 10 areas to help improve global nuclear safety after the Fukushima accident more than five months ago.
While stressing that atomic energy safety was primarily a national responsibility, it signalled a strengthened role for the IAEA and its expert missions to review compliance with international reactor and regulatory standards.
Among the proposed steps in the Nuclear Safety Action Plan, the IAEA would "organize operational safety reviews ... of one nuclear power unit in ten over a period of three years".
It did not give details, but the IAEA has previously suggested plants could be randomly selected for such checks. There are some 440 operating nuclear reactors in the world.
The Vienna-based agency would also conduct regular assessments of national regulatory bodies, the draft said, in an apparent attempt to make sure they were sufficiently independent and resourced to be able to work effectively.
The proposals, aimed at ensuring nuclear plants can withstand extreme events such as the earthquake and tsunami that crippled Fukushima, may prove controversial for states which want to keep safety an issue strictly for national authorities.
The draft builds on the outcome of an IAEA-hosted nuclear safety conference in June. It will be discussed by diplomats of the agency's member states ahead of the U.N. body's decision-making General Conference next month.
The purpose "is to define a programme of work to strengthen the global nuclear safety framework worldwide," the IAEA text said. "Implementation of the actions proposed .... would represent a significant step forward," it added.
Japan's crisis has prompted a rethink of energy policy worldwide, underlined by Germany's decision to close all its reactors by 2022 and Italy's vote to ban nuclear for decades.
Three reactors at the Japanese complex went into meltdown when power and cooling functions failed, causing radiation leakage and forcing the evacuation of some 80,000 people.
But even though IAEA states agree on the need for enhanced nuclear safety, they have voiced differing positions on how much international action is needed.
Nuclear power plant exporters Russia and France have called for stronger international steps, but others are more cautious.
Currently there are no mandatory, international nuclear safety regulations, only IAEA recommendations which national regulators are in charge of enforcing. The U.N. agency conducts review missions, but only at a member state's invitation.
IAEA Director General Yukiya Amano, a veteran Japanese diplomat, faces a difficult task in balancing different views among the agency's some 151 member states.
Under his draft plan, authorities would "promptly undertake a national assessment of safety margins against extreme natural hazards for nuclear power plants ... and to implement the necessary corrective actions."
The IAEA would then conduct "peer reviews of the national assessments," it said.
After the March 11 disaster at Fukushima, Japanese officials came under fire for their handling of the emergency and the authorities have admitted that lax standards and poor oversight contributed to the accident.
The IAEA action plan said states should conduct a national review of their regulatory bodies to ensure their independence. In addition, the IAEA would assess a member state's national regulatory framework every ten years, it said. (Editing by Louise Ireland)