Valery Legasov, who led the Soviet delegation, started blandly enough but then abruptly took flight. Speaking with controlled passion, often departing from his prepared text, he gave a chilling account of the series of errors that had spread 200 times as much radioactivity over Europe as was emitted by the Hiroshima and Nagasaki bombs combined.
On came a film taken by helicopter, and we were suddenly looking, as into a live volcano, down through the black crater of the shattered building on to the red and angry reactor core. A coffee break was called and the nuclear barons emerged, ashen-faced and silent after witnessing something they had long insisted was impossible.
All except one. Lord Marshall of Goring, then the driving force behind Britain's nuclear industry as chairman of the Central Electricity Generating Board (CEGB) seemed unmoved. Unhesitatingly, he gathered a group of journalists who had not been in the room and gave them his own account of what had been said. Glasnost might have come to the Soviet nuclear industry, but not, it appeared, to the British one.
Lord Marshall's line was that Legasov had made it clear that the accident had been caused by the faulty design of the reactor, a type unique to the then Soviet Union, thus proving it could not occur elsewhere. I, on the contrary, had just heard the Russian unambiguously blame human error, which can happen anywhere, thus casting doubt on safety everywhere. Yet the CEGB chief insisted that Britain had nothing to learn from Chernobyl.
Ten years on, as the leaders of the world's richest countries meet in Moscow to mark the grim anniversary, it seems that everyone is singing Lord Marshall's song. Eastern and Western ministers and nuclear industries unite in blaming the reactor. Even Greenpeace agrees.
They all have an interest in this. The former Soviet states want Western aid to refurbish their reactors. Western governments want to minimise the fall-out of the catastrophe for their own nuclear industries. The Eastern nuclear industry stands to receive cash, the Western to fill its shrinking order book with refurbishment work. And Greenpeace wants to set an international precedent by getting all the Chernobyl-type reactors shut down.
Yet the accident happened because the reactor's operators made no fewer than six crucial errors, including switching off all the safety systems that should have prevented disaster. Some mistakes seem to have been made because the operating staff had not been told enough about how the reactor worked. Another, admitted Dr Pierre Tanguy, one of the heads of the French nuclear industry, was "the kind of operator error that we all experience in our plants and is hard to eliminate, but, without it, there would have been no accident".
By four seconds past 1.23am on 26 April 1986, the reactor, as Legasov put it, "was free to do as it wished". Its power surged to several hundred times its normal level in the last second of its life, and an explosion blew its 1,000-ton lid clean off. The radioactive material that streamed out still seriously contaminates an area the size of Denmark, Belgium, the Netherlands and Switzerland combined. The cautious National Radiological Protection Board has estimated that some 30,000 will die of cancer across Europe over the next decade as a result.
Certainly the reactor design was unforgiving of these particular errors. Certainly, too, enormous sums of money must be spent on improving Eastern power stations, and on strengthening the shielding round the Chernobyl ruin, which is now in danger of disintegrating, starting a new disaster. But this does not absolve other designs. The world's dominant reactors, the PWRs, are - for example - far more likely to suffer one of the most feared catastrophes of all, a nuclear meltdown.
This is what almost happened at Three Mile Island in Pennsylvania in 1979. The official commission that investigated the accident concluded that the reactor had come within an hour of complete meltdown, and that only sheer luck had avoided it. If anything, the reactor design played a bigger part in initiating the crisis than at Chernobyl, though human errors then made things worse.
"Safety hangs increasingly on the human error factor and we cannot eliminate it," said a leading nuclear engineer after the accident. One witness at Three Mile Island described how "bells were ringing, lights were flashing, and everyone was grabbing and scratching". Joe Kemeny, the chairman of the commission of inquiry, said, perhaps over-optimistically: "The plants are safe: it's the people who aren't."
The nuclear industry insists that things have since improved: only last week the chairman of the World Association of Nuclear Operators was extolling Western "safety culture". But a book published the very day before he spoke undermined him. Inside Sellafield (Quartet, pounds 9) is perhaps the most devastating book yet on the nuclear industry. Partly because of what it says, but mainly because the author, Harold Bolter, was for 16 years company secretary of BNFL, which owns Sellafield, and for even longer its principal apologist and trouble-shooter.
Bolter describes how buildings containing deadly materials were allowed to deteriorate, amid assurances that they were safe. On one occasion he found the wall of a pond containing nuclear waste bulging and threatening to collapse. Buildings have leaked radio- active waste undetected, sometimes for decades, and there have been so many spills that, he says, a hole dug "virtually anywhere" on the site would reveal radioactive contamination. In 1990, cans of plutonium were found to be in danger of bursting, but the incident was kept "under wraps". Most frightening of all, in September 1992, a worker peering by chance into a cell through "a murky observation window" spotted mounds of spilled plutonium. If they had been in different positions, says Bolter, "there would have been a criticality incident" - a nuclear explosion.
He paints an astonishing picture of secrecy and complacency, with Sellafield often failing to inform even the BNFL management of what was going on. Similar attitudes, said the inquiry into Three Mile Island, had made such an accident "inevitable". And the CEGB's Dr Brian Edmundson concluded at the Chernobyl post-mortem that the root cause of the disaster was that the operators had "lost their fear of the reactor".
The more often people are told that accidents are impossible, the less care they will take. I fear that by passing off the Chernobyl disaster as a peculiar function of a particular design, and by underplaying the universal human factor, environmentalists and nuclear industries alike are increasing the likelihood of another catastrophe.Reuse content