I don’t understand it at all

‘When​ you look at it, it looks like any other piece of land. The sun shines on it like on any other part of the earth. And it’s as though nothing had particularly changed in it. Like everything was the way it was thirty years ago.’ This is the first description of the Zone, the enigmatic and forbidden locus of Arkady and Boris Strugatsky’s novel Roadside Picnic (1972), filmed by Andrei Tarkovsky as Stalker (1979). It’s an uncanny match with Serhii Plokhy’s first impression of Chernobyl as a tourist, thirty years after the explosion there in 1986. His young guide knows the site well enough, though the Soviet world of thirty years ago has faded from memory: she maintains that nobody can recall the identity of a figure portrayed on the wall of an abandoned movie theatre, whom Plokhy instantly recognises as Viktor Chebrikov, the head of the KGB from 1982 to 1988. Some of his companions in the tour group have come all the way from Britain to see Chernobyl precisely because of the parallels with the Zone: they are obsessed with the shooter-survival video game S.T.A.L.K.E.R.: Shadow of Chernobyl, in which the area is filled with radioactive mutants.

‘The further we move in time from the disaster,’ Plokhy writes, ‘the more it seems like a myth.’ He aims to replace the myth with history, drawing on newly released archive material and interviews with eyewitnesses. His narrative is thorough and well organised, but consensus is elusive. Those involved were working with different and often contradictory sets of facts, in the service of mutually incomprehensible agendas and ideologies. (Ronald Reagan, for one, believed that the explosion fulfilled a prophecy in the Book of Revelation, on the grounds that Chernobyl took its name from the Ukrainian for ‘wormwood’.) There is still much disagreement about what happened and why; even more alarming, though the emergency was ended, we still don’t know precisely how.

The RBMK (‘high power channel reactor’), the type of nuclear reactor used at Chernobyl, was developed in the 1970s as a more powerful and safer alternative to earlier water-cooled models. It was based on the reactors used to produce weapons-grade plutonium, with a huge turbine built in to capture the heat the fission reaction generated and transform it into electricity. By 1982 RBMKs were in operation all across the European part of the Soviet Union, and generated more than half of its clean electrical power. They were being built in numbers, with an accelerated design and construction schedule of five years. Anatoly Aleksandrov, the president of the Soviet Academy of Scientists, insisted they were so safe you could instal one in Red Square.

In Prypiat, the industrial new town built in the 1970s outside Chernobyl to house the workers at the power plant, the facilities were new and well constructed, including excellent schools, sports stadiums and swimming pools. Its residents enjoyed the benefits of the nuclear industry’s close ties to the military, and in contrast to most Soviet cities at that time there were plentiful supplies of meat, dairy products and vegetables from the lush surrounding farmland. On Friday, 25 April 1986, the workers in Prypiat were preparing for the spring holiday season. Red Saturday, the ‘voluntary’ day of unpaid labour undertaken to celebrate Lenin’s birthday, was behind them and May Day, Easter and the 9 May holiday marking victory in the Second World War, were ahead. It was unseasonably warm.

The systemic problems of the Chernobyl plant, and of RBMKs in general, were known only to a few. In 1979 the KGB had flagged up serious concerns about the construction standards of Reactor No. 2, and in 1982 a fuel channel in Reactor No. 1 had burst during planned repairs, releasing enriched uranium into the core of the reactor. Plant managers and engineers across the Soviet Union privately admitted that RBMKs were ‘dirty’, typically suffering around five minor leaks and malfunctions per year. The worst accident until then had been in 1975 at the Leningrad plant, where a test that involved stopping the reactor led to an unexpected and rapid rise in the radiation rate which required an emergency shutdown. The underlying design flaw – once the water reached boiling point, voids developed in the coolant system that boosted the chain reaction rather than limiting it – was kept under wraps. After the Three Mile Island nuclear accident in the US in 1979, plants in the West adopted higher construction standards and by 1986 cost seven or eight times more than older models. Soviet plants stuck with the old specifications and the old budgets. At Chernobyl, the construction of Prypiat’s public buildings, such as the splendid marble-clad palace of culture, was often prioritised over the nuclear complex.

Reactor No. 4 at Chernobyl was the newest and believed to be the safest. A shutdown and steam turbine test had long been scheduled for 25 April, and had been carefully planned. The powering down of the reactor had begun the night before; its nominal output of 3200 megawatts had been halved, and was to be reduced further: the prescribed power level for the test was 760 MW. The test was supposed to be completed during the day shift, but the Kiev grid had made an emergency request for power, and now the test would have to wait until after 11 p.m. to be carried out, after a rushed handover, by a less experienced crew on the night shift.

Once the shutdown was resumed, irregularities mounted. The level of activity in Reactor No. 4 was controlled using boron, which damps down a fission reaction by absorbing stray neutrons: insert rods made of boron into the reactor core and the power output goes down; withdraw them and it increases. The seven-metre-long control rods were moved by automatic regulators in and out of the core at 40 centimetres per second. On 25 April one of the regulators malfunctioned; the rods were stuck in the core and the power dropped precipitously to 30 MW. Rather than abandon the test, Anatoly Diatlov, Chernobyl’s deputy chief engineer and the man in charge on the night, decided to continue. The operators regained control of the rods and got the power back up to 200 MW, well below the level prescribed for the test, but high enough, Diatlov thought, to stabilise the reactor.

Meanwhile, they had been ignoring a problem with the water supply to the reactor. They switched on the reserve pumps, which solved the immediate difficulty but caused another one: water absorbs neutrons, so increasing the supply made the power fall again. They switched the reserve pumps off again, and in a further effort to maintain power, continued withdrawing the control rods until finally only 9 out of the 167 in use remained in the reactor core. At this point, Plokhy writes, the nuclear reaction was ‘difficult to control and the reactor highly unstable’.

At 1.22 a.m. the level of water in the reactor dropped too far, causing it to boil and turn to steam. The power began to rise rapidly. But Diatlov and his colleagues were focused on the turbine test, which began at 1.23:04 a.m. By 1.23:40, it was over: for what it was worth, the turbine worked fine. But in the 36 seconds it had taken to carry out the test, the reactor had spun out of control. An emergency shutdown was ordered; Plokhy writes that Leonid Toptunov, the 25-year-old engineer who carried out the order, ‘removed the scrap of paper from the button and pressed it’. This caused all the control rods available to descend into the core at once. That might have worked, but there was one last snag. The boron rods were tipped with graphite; as the rods entered the core, the tips displaced still more water from the reactor – water that had been absorbing neutrons and restraining the reaction – before the boron could get to work. This is what had happened at Leningrad in 1975. There was an enormous power surge. The rise in temperature caused the fuel rods to break. The control rods jammed on the fragments, only a third of their way into the core. Having struggled to get above 200 MW for so long, the power output of the reactor now shot up to 30,000 MW in seconds. A hugely inflated proportion of water in the reactor turned to steam, which had, as Plokhy writes, ‘nowhere to go’.

The workers in the control room heard a ‘sudden roar … of a completely unfamiliar kind, very low in tone, like a human moan’. Then there was a blast, and then, a few seconds later, another. Even at this point nobody grasped what had happened. As Plokhy says: ‘No textbook they had ever read suggested that reactors could explode.’ The first explosion had been caused by the excess steam in the core escaping into the external cooling system, destroying the casing of the reactor. The 200 tonne concrete lid on the reactor – its ‘biological shield’ – was blown through the roof of the building, then landed again, off-centre, so that radiation was now being spat into the atmosphere. The second, bigger blast destroyed much of the building and threw chunks of burning radioactive graphite into the air, which scattered across the surrounding area.

Outside, the ground shook. Locals clustered around the pond just a few hundred metres from the turbine hall saw flames shoot into the sky, but continued their night-fishing. Firefighters arrived five minutes after the explosion – they had heard the blasts and seen the flames from the fire department nearby – and climbed onto the turbine hall roof, which they found littered with ‘luminous, silvery pieces of debris of some kind’. The only doctor on call in Prypiat that night was summoned to the site to treat plant workers and firefighters complaining of headaches and nausea. At first he suspected alcohol poisoning, but as he saw more cases he remembered what little he had been taught in medical school about radiation sickness and requested potassium iodide from the hospital.

Meanwhile, back in the control room in the minutes after the explosion, Diatlov was trying to make sense of the readings on the instruments that were still functioning. He believed the reactor had already shut down, and guessed that the control system’s water tank had exploded, in which case the fuel rods would be disintegrating. ‘Cool the reactor at emergency speed,’ he ordered, at which point he discovered that the control rods were jammed and the fission reaction was still going on. He rushed to the turbine hall and found it on fire, stars shining through its collapsed roof. The radiation levels, he realised, must be extreme. He was soaked with water from the broken coolant pipes, and began to feel nauseous and unsteady on his feet. Viktor Briukhanov, the director of the plant, had arrived and wanted to know what had happened. ‘I don’t understand it at all,’ Diatlov replied. It was impossible to admit to his boss that the reactor had exploded. (‘The stress was too great’, the head of Chernobyl’s Communist Party committee admitted a few months later, ‘and our belief that the reactor could not explode was also too great.’) Even the following morning, as the reactor continued to spew fission products – iodine-131, caesium-137 and xenon-133 – into the atmosphere, the bewildered control room operatives remained convinced that ‘we did everything right.’

Nobody​ had any relevant experience and there were no protocols. Only two options were available: denial or panic. As reports spread, bureaucratic sclerosis took hold. At the 27th Party Congress, the Soviet minister of energy, Anatoly Maiorets, had just promised to double the number of Soviet nuclear reactors and to build them in record time. The Ukrainian government told Moscow that an accident had occurred but was under control. Mikhail Gorbachev was told there had been an explosion and a fire at Chernobyl but that the reactor was intact. When Maiorets and his expert colleagues arrived at the scene, they inherited the burden of responsibility from Briukhanov and Diatlov. In impotent fury, one of them kicked a graphite block that was later found to be emitting two thousand roentgens of radiation per hour, a potentially fatal dose. Their eyes smarted and they had difficulty breathing, but they still refused to countenance the idea that the reactor had exploded, and with it the implication that, if the same thing happened at other reactors, most of Europe could be rendered uninhabitable.

It was only when a helicopter flew over the site and had a direct view into the reactor, glowing cherry red with heat, that the truth became impossible to deny. By this time the staff at Prypiat hospital, alarmed by high contamination readings, were scrubbing the wards and corridors. Eventually they realised the radiation was being emitted by their patients. Radiation sickness on this scale had not been witnessed since Hiroshima and Nagasaki. The firefighters who absorbed the highest levels of radiation now had deep tans and were vomiting convulsively. Medics treated them with milk, nitrite injections and potassium iodide until radiation specialists arrived from the Ministry of Health in Moscow. They tested white blood cell counts and identified 28 priority cases; these people were flown immediately to Moscow for treatment. The specialists warned the local medics that symptoms tended to fade but could return with greater severity after a latency period of around ten days.

On the morning of Sunday 27 April, with radiation levels still rising, it was decided that Prypiat had to be evacuated. Many of its residents, who had been assured time and again of their safety from nuclear accidents, refused to believe in the invisible threat. ‘What sort of danger is this?’ they wanted to know. ‘When the Germans were here, that was real danger. But now? It’s sunny and warm; we need to tend our gardens.’ Film footage of a wedding in town that day shows young people in summer clothes playing football on sports fields and eating ice cream, but flashes and sparks in the images are evidence of radioactive particles penetrating the lens. Some residents noticed a metallic smell in the air, and as army trucks and helicopters moved in they had their first presentiment that, as one of them put it, their world was changing ‘from the old, clean world we used to know, into our new poisoned age, the age of Chernobyl’.

The following day, radiation levels in Kiev were five times the norm. The May Day parade was scheduled for the following weekend and tens of thousands would be taking part. Party leaders in Moscow decided to proceed as planned, and Pravda ran a brief official statement claiming that the situation in Chernobyl was improving. On May Day morning, radiation levels rose rapidly, especially on Khreshchatyk, Kiev’s main street (it runs through a valley, which has the effect of concentrating radiation). Some of the marchers noticed that the party members’ podium was half-empty, and wondered ‘where are the energy people?’ Others reported dizziness and dry throats. When the truth finally emerged and the cover-up was exposed, the parade was recalled with a fury that eroded the authority of the regime it had been designed to glorify. As one Kiev resident later wrote to the Ukrainian parliamentary commission: ‘My government deceived and betrayed me. When the Chernobyl disaster took place, I learned of it not from my government but from a foreign one abroad.’

By early May the Soviet media was losing control of the story. On the morning of 28 April the Forsmark nuclear power plant in Sweden had detected high radiation levels emanating from Ukraine. The next day there was a report in the New York Times and a briefing from the CIA announcing the worst nuclear accident in history, with hundreds if not thousands of deaths. Moscow shifted from denial to drastic action. A 30 kilometre exclusion zone was imposed around the site, and the Central Committee ordered helicopter airdrops to cover the exploded reactor with sand, lead, clay and boron, to quell the activity in the reactor. If temperatures and pressure kept rising, the radioactive core would burn its way down to the water table, after which the River Dnieper would carry the contamination into the Black Sea and on to the Mediterranean.

On 21 May Yefim Slavsky, the 88-year-old head of the Soviet nuclear programme, was put in charge of ‘burying’ the reactor: sealing it permanently to stop any further emission of radiation. He ordered that the whole reactor building be encased in a concrete ‘sarcophagus’. ‘Whole towns’ rose up in the area, Plokhy writes, ‘new roads and railway lines, as well as entire concrete-production plants’. The highly contaminated square kilometre around the reactor was scrubbed clean, and a concrete wall six metres thick was built around the reactor, to make it safe enough to work in the area. Slavsky’s plan was to cover the reactor with an eight tonne aluminium cupola lowered by helicopter onto the perimeter wall. But the helicopter dropped it from a height of 400 metres on the way to the site, and it smashed. In the end the ceiling of the sarcophagus was made of concrete too. The job was finished by mid-November; 200,000 workers had been used to build the 400,000-tonne structure. They had worked in shifts to minimise their exposure to radiation, but no one was under any illusions: the ‘liquidators’, as they were known, had accepted a sacrificial role in the cause of damage limitation. Many approached it as they had their service in the Red Army, as a moral and patriotic duty, though the authorities undermined their sense of heroism by rewarding conspicuous risk with financial bonuses. One of the divers who released contaminated water from the underground chambers at the plant, when publicly presented with an envelope of cash, crumpled it up in embarrassment. ‘He found it inconvenient to refuse the money,’ but had taken on the risks ‘not thinking of any incentives’. He was dead within weeks.

A rift opened up between the authorities in Ukraine, which advocated openness and energetic solutions, and Moscow, which was focused on controlling information and minimising disruption. Nearly a third of Soviet media coverage was dedicated to countering Western exaggerations of the scale of the disaster. Gorbachev worried that ‘a kind of mass psychosis is developing … the name of Gorbachev is starting to get a thrashing throughout the world in connection with that accident.’ He was being pushed further and faster into glasnost than he wished, but he had little choice.

In early July, the Politburo convened to hear testimony from experts. The systemic failures were largely glossed over; the disaster was blamed on procedural violations by the workers in the control room. Briukhanov and Diatlov were among six staff charged with negligence. Their trial was held that month in Chernobyl; despite the radiation levels, Soviet law stipulated that the proceedings must be held at the site of the alleged crime. Both were sentenced to ten years in prison. (They served five years. Briukhanov is still alive; Diatlov died in 1995 of heart failure.) On 25 August, at a conference of the International Atomic Energy Agency (IAEA) in Vienna, Valerii Legasov of the Kurchatov Institute of Atomic Energy came clean, with a 388-page report that exposed many of the secrets, and the defects, of the Soviet nuclear programme. He received a standing ovation.

The political fallout from Chernobyl contributed to, and perhaps hastened, the collapse of the Soviet Union. On 26 April 1988 the first non-state-controlled rally in living memory assembled on the Maidan in Kiev under banners that read ‘Atomic energy stations out of Ukraine’ and ‘We do not want dead zones.’ From it emerged an ecological pressure group which grew into a People’s Movement of Ukraine, with an ‘eco-nationalist’ agenda that linked the campaign to close Chernobyl with demands for political autonomy. After independence in 1991, however, Ukraine’s economy collapsed along with Russia’s. By 1994 its GDP had halved, and the only way to meet its energy needs was to return to nuclear power. The parliament of eco-nationalists that had enshrined the rights of Chernobyl’s victims in law was obliged to reverse its moratorium on building new nuclear plants. The cost and responsibility for making Chernobyl safe devolved to the international community and the World Bank.

In 2000 the Chernobyl power plant was finally decommissioned. Like the fictional Zone, it has become a silent, abandoned industrial wasteland, slowly being reclaimed by nature. The disaster is both history and myth: it has been exhaustively investigated, yet the basic facts have still not been established. The death toll, for example, has been fixed at just two from the explosions themselves and a further 29 from radiation sickness during the three months afterwards: close to Soviet reports at the time, and far short of the thousands claimed by Western media and intelligence sources. But the long-term figure can only be guessed at. The United Nations’ estimate in 2005 of four thousand deaths is at the low end of a spectrum which extends, in Greenpeace International’s estimate, to ninety thousand. Assessments of the present and future risk continue to diverge. According to Igor Gramotkyn, the current director of the Chernobyl power plant, the site will be a no-go area for at least 20,000 years; other sources think it may be habitable in three centuries, and observe that populations of wolves, bears, beavers and otters are already thriving. By 2000 3.5 million Ukrainians were claiming state benefits as radiation sufferers; yet dozens of elderly former residents have returned to live (and die) in the exclusion zone, and the World Health Organisation has determined that radioactivity-related mutations and birth defects are statistically insignificant.

As for the lessons to be learned from Chernobyl, Plokhy’s conclusion is anything but reassuring. ‘Even today,’ he writes, ‘we do not know which of the strategies the Soviets tried and the technological solutions they implemented actually worked. Could some of them have made things worse? The eruption of the nuclear volcano stopped for reasons that the scientists and engineers could not comprehend, just as they were initially at a loss to explain why the reactor had exploded in the first place.’ There are 11 RBMKs still in operation today, in Kursk, Leningrad and Smolensk.