A preliminary report by the UN's International Atomic Energy Agency has stated that the response to the Fukushima nuclear incident was "exemplary" and that nobody has been harmed by radiation exposure resulting from it.

The report was drafted by an IAEA fact-finding team which has just completed a visit to Japan. The team was led by Mike Weightman, the UK Chief Inspector of Nuclear Installations – Britain's top nuclear regulator.

The IAEA team give a brief account of the events of the earthquake – which the affected powerplants resisted without difficulty, despite it being far stronger than they were designed to withstand – and the following tsunami, which caused serious damage at Fukushima Dai'ichi. Only one backup diesel generator survived the enormous wave, at 14m high more than twice as tall as the plant's defences could take.

Now that the situation at the plant has stabilised and investigations inside the reactor buildings have been undertaken, it appears that fuel elements in the worst-hit reactors actually melted down quite soon after most of their cooling equipment was knocked out. This situation is usually assumed to be catastrophic – the very word "meltdown" has come to mean "a rapid or disastrous decline or collapse" – but in fact, apart from putting the reactors beyond economic repair, it has had no serious consequences (as was also the case at Three Mile Island).

As the IAEA notes:

To date no health effects have been reported in any person as a result of radiation exposure from the nuclear accident.

The preliminary report goes on to praise the way the plant staff handled the crisis:

The response on the site by dedicated, determined and expert staff, under extremely arduous conditions has been exemplary and resulted in the best approach to securing safety given the exceptional circumstances.

The operations of the incident command and support base, set up at the nearby "J-Village" football training centre, are particularly highly praised for the careful management of the various workers based there. The careful Japanese practice of having hardened emergency-response centres on site from which to conduct operations during a crisis is also recommended to other nuclear operators worldwide.

The IAEA team bluntly contradicts the many suggestions from the media and anti-nuclear campaigners that information on the incident was or is being withheld or suppressed by the Japanese authorities, or by plant operator TEPCO.

During the IAEA mission, the team of nuclear experts received excellent co-operation from all parties, receiving information from many relevant Japanese ministries, nuclear regulators and operators ... The Japanese Government, nuclear regulators and operators have been extremely open in sharing information and answering the many questions of the mission.

Weightman and his team add that efforts should now be directed at allowing local people to return to their homes and get on with their business. In general the Japanese authorities exercised commendable restraint in the face of overseas suggestions that the evac zone should be enlarged, but it did in the end embark on some compulsory evacuations that were hard to justify on safety grounds. The IAEA seems to suggest that it will be feasible to clean up any long-lasting contamination in the area - for instance from radioisotopic caesium, whose presence resulted in areas of farmland being abandoned following Chernobyl.

The report says:

The planned road-map for recovery of the stricken reactors is important ... It should be seen as part of a wider plan that could result in remediation of the areas off site affected by radioactive releases to allow people evacuated to resume their normal lives. Thus demonstrating to the world what can be achieved in responding to such extreme nuclear events.

In other words, it appears that in the IAEA's opinion not only will nobody be radiologically harmed by the Fukushima incident, but it ought to be possible to ensure that normal life – living, working, farming etc – can resume in the evacuation zone. TEPCO has already stated that it expects to restart two of the Fukushima reactors in due course (both Three Mile Island and Chernobyl resumed operation as power stations following their accidents, too).

A fuller report will be delivered at a summit conference in Vienna later this month. For now the preliminary document and accompanying information can be found here on the IAEA website. ®