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April 26, 1986

The Chernobyl Disaster

A reactor exploded in Soviet Ukraine, and the world learned about it from a Swedish shoe scanner

Clay Gilliland, CC BY-SA 2.0, via Wikimedia Commons

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On the morning of the twenty eighth of April, nineteen eighty six, a routine radiation monitor at a nuclear plant in Sweden went off as a worker walked in from outside.

They checked their own reactor first, and found nothing wrong with it. Then they worked out that the contamination was on his shoes, that it had come in from the air, and that the wind that morning was coming from the southeast.

That is how the world found out. Two days after the explosion, from a shoe, in a different country.

Scene 1Twenty three minutes past one

One twenty three and forty seconds in the morning. Reactor number four at the Chernobyl plant in Soviet Ukraine.

The operators are running a safety test. It is a rehearsal for a blackout: they want to know whether the spinning turbine can power the cooling pumps in the seconds before the diesel generators start.

The test has already been delayed for hours, and has been handed to a night shift that did not plan it and did not expect to run it.

They press the button marked A Z five. It is the emergency shutdown. It drives every control rod into the core at once, and it is the thing you press when you want the reaction to stop.

Because of how the rods were built, with graphite on their tips, the first thing they did on the way in was displace water and briefly increase the reaction rather than stop it.

Within seconds the core was at more than a hundred times its rated power.

The Ferris wheel in the Pripyat amusement park, which was due to open on May 1, 1986. The city of 49,000, built for plant workers, was evacuated on April 27 and has stood empty ever since. Photographed in 2010.
The Ferris wheel in the Pripyat amusement park, which was due to open on May 1, 1986. The city of 49,000, built for plant workers, was evacuated on April 27 and has stood empty ever since. Photographed in 2010.Giles Thomas, CC BY-SA 2.0, via Wikimedia Commons (2010)

Scene 2The roof

Two explosions lifted the upper shield of the reactor, a disc of steel and concrete weighing a thousand tonnes, and dropped it back at an angle. The reactor hall was open to the sky.

Burning graphite from the core was thrown across the site and onto the roof of the neighbouring reactor building.

Firefighters arrived five minutes later. They had no protective clothing, no dosimeters worth the name, and no reason to believe this was anything other than a fire.

They scraped glowing chunks of reactor graphite off the roof with their boots. Some described a metallic taste. Several of them were dead within weeks.

A wide view of the Chernobyl Nuclear Power Plant, whose Reactor No. 4 exploded during a botched safety test at 1:23 a.m. on April 26, 1986. Photographed in 2013.
A wide view of the Chernobyl Nuclear Power Plant, whose Reactor No. 4 exploded during a botched safety test at 1:23 a.m. on April 26, 1986. Photographed in 2013.Tiia Monto, CC BY-SA 3.0, via Wikimedia Commons (2013)

Scene 3Thirty six hours

Three kilometres away was Pripyat: a city of forty nine thousand people, built in nineteen seventy to house the plant's workers. The average age was twenty six.

On the morning of the twenty sixth, children went to school. People fished on the cooling channel. There were weddings that afternoon.

Above them an open reactor core was burning in the air.

The evacuation came on the afternoon of the twenty seventh, roughly thirty six hours after the explosion. Twelve hundred buses came from Kyiv. Residents were told to bring documents and enough for three days.

They were never allowed back. The city is still there, and still empty.

That is the entire announcement. Two and a half days, four sentences, no evacuation notice, and no mention that the fire was still burning.

The destroyed Reactor No. 4 under the steel and concrete shelter built to contain the roughly 200 tonnes of melted fuel and debris left inside. Photographed in 2019 before the New Safe Confinement was rolled fully into place.
The destroyed Reactor No. 4 under the steel and concrete shelter built to contain the roughly 200 tonnes of melted fuel and debris left inside. Photographed in 2019 before the New Safe Confinement was rolled fully into place.Mattias Hill, CC BY-SA 4.0, via Wikimedia Commons (2019)

Scene 4The liquidators

Roughly six hundred thousand people were eventually sent into the zone to clean it. They were called liquidators.

On the most contaminated section of roof, robots failed. The radiation destroyed their electronics. So men were sent instead, in lead aprons, running out to shovel graphite for ninety seconds at a time before running back.

Many were conscripts. Many were never told their real dose.

What most of them received afterwards was a certificate confirming they had been there.

Five accounts

Chernobyl is not really disputed as a sequence of events. What is disputed is who it belongs to, and how many people it killed.

  1. The Soviet state
  2. The liquidators and the evacuated
  3. The epidemiologists
  4. The reactor engineers
  5. Glasnost and the collapse

The turn

Each account leaves out what would most complicate it.

  1. Soviet State / Official Containment

    The Soviet account leaves out the positive void coefficient, the thirty six hours, and the suppressed readings.

    From the record
    The RBMK reactor's positive void coefficient and flawed control-rod design
    The 36-hour delay in evacuating Pripyat
    The suppression of true radiation readings from the affected population
  2. Liquidators and Evacuees

    The liquidators' account leaves out that the containment they built actually worked, and that without them it would have been far worse.

    From the record
    The engineering necessity that drove the liquidator mobilization
    The genuine effectiveness of the containment they accomplished
    Statistical and epidemiological framing of the health outcomes
  3. Scientific / Epidemiological Dispute

    The epidemiological account leaves out the testimonial reality that a confidence interval cannot hold, and it leaves out that the nuclear industry has an interest in the low number.

    From the record
    The individual testimonial reality that statistics cannot capture
    The political stakes for the nuclear industry in a low number
    Non-fatal health and psychological burdens of contamination
  4. Nuclear Industry and Reactor Safety

    The engineers' account leaves out the people almost entirely. It is an account of a machine.

    From the record
    The human and testimonial cost of the disaster
    The industry's own incentive to frame Western designs as categorically safe
    The political and information-control dimensions of the Soviet response
  5. Glasnost and the Fall of the USSR

    And the political account leaves out everything that is not political: the health effects, the emptied towns, and the other causes of Soviet collapse that had nothing to do with a reactor.

    From the record
    The disaster's non-political human and epidemiological dimensions
    The many other causes of Soviet collapse (economic stagnation, Afghanistan, arms race)
    The genuine engineering success of the containment

Close

The reactor is now inside a steel arch, a hundred and eight metres high, moved into place in twenty sixteen. It is designed to last a hundred years, which is not the same as being finished.

Pripyat is still standing. The school, the swimming pool, the fairground with a ferris wheel that was due to open five days after the explosion and never carried a passenger.

The exclusion zone is now, by some measures, one of the more successful wildlife reserves in Europe, which tells you what the main threat to wildlife in Europe usually is.

And the world still found out from a shoe.

The record

By the numbers

Span
1986
Killed
31immediate, Soviet official to 4,000, WHO/IAEA projection…
Displaced
115-350Kevacuated and resettled; roughly 600,000 liquidators; 5…
Place
Ukraine

Key figures

  • Mikhail GorbachevGeneral Secretary of the Communist Party; his glasnost policy was tested and hardened by the state's failure to disclose the disaster1931 to 2022
  • Valery LegasovChemist who led the Soviet delegation to the IAEA in Vienna; presented the accident report, then died by suicide on the second anniversary1936 to 1988
  • Anatoly DyatlovDeputy chief engineer who supervised the fatal test; sentenced to 10 years, maintained the reactor's design was to blame1931 to 1995
  • Viktor BryukhanovPlant director; convicted of gross safety violations and sentenced to 10 years' labor camp1935 to 2021
  • Vasily IgnatenkoPripyat firefighter who died of acute radiation syndrome; his widow Lyudmilla's testimony opens Svetlana Alexievich's oral history1961 to 1986
  • Svetlana AlexievichBelarusian writer whose Voices from Chernobyl collected survivor testimony; awarded the 2015 Nobel Prize in Literature1948 to ?
  • Serhii PlokhyHarvard historian whose Chernobyl history won the 2018 Baillie Gifford Prize; argues the disaster exposed the fatal flaws of the Soviet system1957 to ?

Primary sources

USSR report to the IAEA · Report presented by the USSR at the IAEA Post-Accident Review Meeting, Vienna, August 1986, as quoted by a Commission of the USSR State Committee for the Supervision of Safety in Industry and Nuclear Power in INSAG-7, Annex I (IAEA, 1992), p. 60 · August 1986

“the prime cause of the accident was an extremely improbable combination of violations of instructions and operating rules committed by the staff of the unit.”

A.A. Gromyko · Extraordinary Session of the CC CPSU Politburo, April 28, 1986, working copy (National Security Archive translation, document 4) · April 28, 1986

“The statement should be written in such a way that it does not cause excessive anxiety or panic.”

Mikhail Gorbachev · CC CPSU Politburo session of July 3, 1986, as recorded in Anatoly S. Chernyaev's notes (National Security Archive translation, document 15) · July 3, 1986

“The [station] personnel are to blame for the accident; but the scale of the accident is due to the design of the reactor.”

Vladimir Gubarev · Letter from the science editor of Pravda to the CC CPSU about his trip to Chernobyl, May 4 to 9, 1986 (National Security Archive translation, document 12) · May 1986

“The situation with radiation in the city was clear within an hour. No planned emergency evacuation measures existed: people did not know what to do.”

A liquidator, as his child reports it · Svetlana Alexievich, Voices from Chernobyl, Children's Chorus, translated by Keith Gessen (Dalkey Archive Press, 2005), as excerpted on NobelPrize.org · 2005

“In parting they shook our hands and gave us certificates of gratitude for our self-sacrifice.”

The Chernobyl Forum · Chernobyl's Legacy: Health, Environmental and Socio-Economic Impacts, second revised version (IAEA, April 2006), p. 15 · 2006

“It is impossible to assess reliably, with any precision, numbers of fatal cancers caused by radiation exposure due to Chernobyl accident.”

World Health Organization · Joint news release, Chernobyl: the true scale of the accident, Geneva · September 5, 2005

“A total of up to 4000 people could eventually die of radiation exposure from the Chernobyl nuclear power plant (NPP) accident nearly 20 years ago, an international team of more than 100 scientists has concluded.”

UNSCEAR · Sources and Effects of Ionizing Radiation, UNSCEAR 2008 Report, Volume II, Annex D, paragraph 98 (United Nations, 2011) · 2011

“The Committee has decided not to use models to project absolute numbers of effects in populations exposed to low radiation doses from the Chernobyl accident, because of unacceptable uncertainties in the predictions.”

International Nuclear Safety Advisory Group · INSAG-7, The Chernobyl Accident: Updating of INSAG-1, Safety Series No. 75-INSAG-7 (IAEA, 1992), conclusion (2), p. 23 · 1992

“The accident is now seen to have been the result of the concurrence of the following major factors: specific physical characteristics of the reactor; specific design features of the reactor control elements; and the fact that the reactor was brought to a state not specified by procedures or investigated by an independent safety body.”

Ian Fairlie and David Sumner · The Other Report on Chernobyl (TORCH), commissioned by Rebecca Harms MEP, Greens/EFA, executive summary, p. 11 · April 2006

“However the statement is misleading, as the figure calculated in the IAEA/WHO report is actually 9,000 fatalities.”

Greenpeace · The Chernobyl Catastrophe: Consequences on Human Health (Greenpeace, Amsterdam, 2006), p. 10 · April 2006

“The most recently published figures indicate that in Belarus, Russia and the Ukraine alone the accident resulted in an estimated 200,000 additional deaths between 1990 and 2004.”

National Report of Ukraine · 20 years after Chornobyl Catastrophe. Future Outlook: National Report of Ukraine (Kyiv, Atika, 2006), p. 8 · 2006

“Radiation contamination maps and radiation level data were classified until 1989.”

Svetlana Alexievich · Nobel Lecture, Swedish Academy, Stockholm · December 7, 2015

“We, Belarusians, had become the people of Chernobyl.”

Mikhail Gorbachev · Turning Point at Chernobyl, Project Syndicate · April 14, 2006

“Indeed, the Chernobyl catastrophe was a historic turning point: there was the era before the disaster, and there is the very different era that has followed.”

A. N. Makukhin, First Deputy Minister of Energy and Electrification of the USSR · Regarding the Accident at Reactor No. 4 of the Chernobyl Nuclear Power Plant, urgent report to the CC CPSU Politburo (National Security Archive translation, document 2) · April 26, 1986

“On 04/26/86 at 1:21 AM during the decommissioning of energy block No. 4 of the Chernobyl NPS during planned maintenance, after the reactor had been stopped, there was an explosion in the upper part of the reactor compartment. According to the director of Chernobyl NPS the explosion caused the collapse of roofs and parts of the wall paneling of the reactor compartment, several panels of the roof in the machine hall and a unit of the auxiliary systems of the reactor compartment, and also a roof fire. At 3:30 AM the fire was extinguished. Measures are being taken by the staff to cool down the active zone of the reactor. In the opinion of the three main administrators under the USSR Ministry of Health, the adoption of special measures, including evacuating the population from the city, is unnecessary.”