UN atom safety plan to win backing despite criticism

* Some states disappointed over "weak" IAEA proposals

* U.S., India and others resist mandatory steps--diplomats

* U.S. ambassador denies safety plan watered down

By Fredrik Dahl

VIENNA, Sept 8 (Reuters) - The U.N. atomic agency's 35-nation governing board is expected next week to endorse steps to boost global nuclear safety in the wake of Japan's Fukushima crisis, even though some disappointed diplomats say the proposals have been watered down.

Japan's reactor disaster six months ago spurred a rethink about nuclear energy worldwide and calls for more concerted measures, including beefed-up safety checks of reactors, to make sure such an accident does not recur.

But divisions have since emerged between countries advocating stronger international commitments and others who want to keep safety as a strictly national responsibility.

The first group includes European nations which have turned their back on atomic energy since Fukushima -- such as Germany and Switzerland -- but also France and Canada, both exporters of nuclear technology, and others, diplomats say.

The United States, India, China and Pakistan -- all big nuclear countries -- are among those resisting any moves towards mandatory outside inspections of their atomic energy facilities.

"They have very strong red lines," one European envoy said.

Seeking the middle ground, the International Atomic Energy Agency (IAEA) appears to have gradually lowered its ambitions in a series of drafts over the last few weeks.

The latest versions presented to member states for feedback have put increased emphasis on the voluntary nature of the measures, also regarding the central issue of nuclear plant inspections organised by the IAEA, so-called peer reviews.

"It is weak," another European diplomat said of the six-page document, which will be discussed by the IAEA's board of governors at a Sept. 12-16 meeting in the Austrian capital.

U.S. envoy Glyn Davies rejected such criticism of the plan.

He said all states should "take advantage of peer reviews", but also that they "must at the end of the day" take responsibility for their own nuclear programmes.

"This really will be the beginning of a process that will go on for some time," Davies told reporters about the proposals.

A ministerial conference in June asked the Vienna-based U.N. agency to draw up the action plan to enhance standards both in the way reactors are built to withstand natural disasters and in the way the industry is regulated.

FROM "COMMIT" TO "ENCOURAGED"

IAEA Director General Yukiya Amano proposed at the same meeting that the agency could review 10 percent of the world's some 440 reactors during a three-year period. He also suggested that they could be randomly selected for safety inspections.

"That language was erased by member states. They've made no firm commitment to do any peer reviews," said nuclear expert Mark Hibbs of the Carnegie Endowment for International Peace.

"Reactor safety after Fukushima remains firmly in the hands of sovereign national governments."

Diplomats say the document is still likely to be adopted by consensus next week, even though some critical states may decide to voice their disappointment at the closed-door board meeting.

The political impact of the massive earthquake and huge tsunami that caused Japan's crisis was particularly strong in Europe, highlighted by Germany's move to close all its reactors by 2022 and Italy's vote to ban nuclear power for decades.

Fuel rods in three reactors at the Japanese complex started melting down when power and cooling functions failed, causing radiation leakage and forcing the evacuation of some 80,000 people. It was the world's worst nuclear accident in 25 years.

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.

Regarding these kinds of safety missions, the draft action plan was amended to say that states would be "strongly encouraged to voluntarily host IAEA peer reviews". Earlier, it said they would "commit to periodically invite" them.

In another section, an early text said each nuclear energy country would "host at least one IAEA Operational Safety Review Team (OSART) mission during the coming three years".

Later versions added the word "voluntarily".

Amano told Reuters last month that adoption of the plan would lead to a "steady improvement" in nuclear safety.

Environmental group Greenpeace said nuclear power could never be safe and there was always a risk of "unpredictable" disasters, such as the one that hit Fukushima.

"IAEA has no mandate to enforce any measures ... therefore we can't expect it will come up with any significant improvement on nuclear safety on the ground," said Jan Beranek, head of the group's nuclear campaign.

(Editing by Mark Heinrich)