Leading article: Japan's disaster must prompt a new look at reactor safety

Amid the apocalyptic scenes reaching our television screens from northern Japan, it seems invidious to address just one aspect of this catastrophe or to draw any conclusions – so recently did disaster strike and so comprehensive is the destruction. Already, however, the disaster has posed with a new urgency a question that seemed to have been retreating from global concerns in recent years: how safe, really, is nuclear power?

Japan, given its history, had every reason to be among the most circumspect countries in developing and harnessing nuclear power. Its geography argued for double, treble, the precautions that might be taken anywhere else. And until last week, the safety measures appeared more than adequate. Japan had a safety record, and a reputation for integrating safety into design, that was second to none. The famed national discipline and resilience of the Japanese was seen as an added asset, in the event of anything untoward.

Until now, it had also been possible to cite Japan's experience to rebut fears about the safety of nuclear reactors. There was always something particular about previous nuclear accidents that would not, it was assumed, be replicated in Japan. America's worst nuclear accident, at Three Mile Island, was the consequence of a mechanical failure that caused the reactor core to overheat. New regulations and design changes followed. The most destructive of all nuclear accidents, at Chernobyl, in Ukraine, whose 25th anniversary – by a cruel quirk of fate – will be commemorated in just one month, reflected shortcomings in design, but also the neglect of infrastructure and general indiscipline that attended the last years of the Soviet Union. Nuclear power in Japan, it was widely accepted, was at a whole different level of reliability.

All assumptions about the safety of nuclear power must now be open to challenge. Maybe it will turn out that there was more that Japan's regulators could have done to ensure the safety of the reactors at Fukushima. Already some are highlighting criticisms voiced previously in Japan, alleging trade-offs between safety and cost. It is also possible that the extensive safety measures that were in place minimised the escape of radiation. Officials appeared confident yesterday that a meltdown of the cores of two reactors had been, if not prevented, then contained.

Even the best-case scenario, however, will not suffice to allay the doubts about nuclear power that have nagged so many for so long. Granted that this was a natural disaster far off the scale of anything ever envisaged, even for Japan's fragile geology, the implications are still grave. If the Japanese, with all their understandable inhibitions about anything nuclear and all their world-leading technology, cannot build reactors that are invulnerable to disaster, who can?

This big question reverberated almost immediately in a small way in Britain. With the Coalition committed to a new nuclear power programme – a policy to which the generally anti-nuclear Liberal Democrats reluctantly signed up – the Energy Secretary, Chris Huhne, announced that he had commissioned a report from the UK's Chief Nuclear Inspector on the "implications of the situation in Japan and lessons to be learnt".

Pressed in a subsequent BBC interview, Mr Huhne ducked the possible impact on British public opinion of the situation in Japan, insisting that the public would form its opinion based on the inspector's report. That may reflect wishful thinking on his part. The pictures from Japan, the reports of radiation leaks, the evacuation ordered for 200,000 people within a 20km radius of Fukushima and the memories refreshed by the Chernobyl anniversary will all affect opinion, not just in Britain, but around the world.