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The Most Dangerous Room in the World

The Most Dangerous Room in the World

The control room of reactor number four at the Chernobyl Power Plant was a maze of control panels. Dials lined every observable surface and the room was a cacophony of beeping, providing the backdrop for a menagerie of engineers, scientists

This was the scene on the evening of 25th April 1986 as workers prepared to run a routine test to determine how long coolant could be pumped into the reactor core in the event of a loss of power. What followed would live long in infamy. A combination of human error and flawed reactor design resulted in a devastating chain of events that led the complete meltdown of the core, major fires and eventually the single worst nuclear accident in human history. Up to 7 million people across Europe were affected by the disaster, with the results of significant exposure to radiation only now being observed in some communities.

How did the meltdown at Chernobyl happen?
The evening began with a simple test to determine how long the reactor’s turbines would continue to spin and allow for water to be pumped into the system to cool the core, in the case of a loss of power.

The test was doomed from the start. It was coordinated by non-nuclear scientists, more aware of the electrical systems and engineering underpinning the plant. Furthermore, there was little communication with the nuclear scientists and hence the impact of the test on the nuclear reactions taking place in the core were not properly assessed.

There was a lax approach to safety in many aspects of the plant and this was on display on that fateful evening in 1986: early in the process the emergency core cooling system, which pumps coolant into the reactor in an emergency to prevent a meltdown, was manually shut down.

The test should perhaps have been abandoned just after midnight, when the power of the system in reactor four fell well below minimum requirements. This was slightly ameliorated by withdrawing a number of control rods, which control the rate of fission reactions taking place.

Due to the design of the reactor, a rapid reduction in power led to a power surge. As the turbine slowed, slightly warmer water entered the active nuclear fission reactor at a slower rate. There, it got hotter and hotter as it came into contact with the active nuclear reactions. The water, which acts to control the nuclear fission by absorbing neutrons crucial to the chain reaction, boiled away.

The power surged higher and higher, fission reactions continued unabated and more and more water boiled into steam.

Water, like all liquids, increases in volume substantially when it is boiled. Therefore, enormous pressures were set up as more and more water boiled. The result was an enormous steam explosion, quickly followed by another due to a build-up of Hydrogen. The contents of the core, structural materials and supporting structures were catapulted in all directions, leading to several fires. The thick smoke and exposed core dumped highly radioactive material around the sight and several hundred miles to the northwest. Attempts to reduce the impact of the disaster only worsened the crisis – sand and other minerals dropped by helicopter targets missed their targets and destroyed surrounding structures and worsened the fallout and attempts to smother the ongoing nuclear reactions may have in fact acted as heat insulators, increasing the heat and reactivity of the meltdown.

In the aftermath of the event, the Soviet government scrambled to complete a cleanup process unlike anything carried out before. Around 600,000 “liquidators” – firefighters, engineers and other workers – were flown in to contain the flow of ionising radiation emitting from the plant and investigate exactly what had gone wrong. The most unlucky crews were required to pick their way through the destroyed core of the reactor and its surrounding rooms. They picked their way through the darkness, directed only by the relentless clicking of their Geiger Counters, which revealed the invisible killer swarming them at all times.

About 6 months after the explosions, workers exploring the rooms directly underneath the reactor reached an area that caused their instruments to scream. Just around the corner was an area so deadly that no living thing could safely go near it. The liquidators constructed a crude camera on wheels and gently pushed it into the near-darkness. What the camera saw was a wrinkled mass of melted nuclear fuel, sand, steel and concrete. It had disintegrated the reactor housing and seeped through the floor, settling in the space below. The mass remained unfathomably hot and released periodic puffs of steam, as if it were taking rasping breaths. Above all, the mass, which came to be known as ‘The Elephant’s Foot’, which despite measuring around one metre across weighed an astonishing two tonnes, was unbelievably radioactive.

Few photographs of this terrifying room exist but, amazingly, one that does was taken by one of the workers, standing just feet from it. The image was taken around ten years after the meltdown and the Elephant’s Foot was only emitting 10% of the radiation it once did. Still, though, just over 8 minutes of exposure would result in a lethal dose. We do not know what happened to the thinly-clad worker interacting with the mass in this photograph, but they would have certainly received a potentially life-changing dose of radiation. The grain throughout the photograph and the ghostly effect of the worker is not an artistic choice. These effects are created by the ionising radiation crackling throughout the room interacting with the photographic film.

[US Department of Energy]

Though the collection of data and photographs may have contributed to an untimely death for this worker, today photographic film is used to save lives for those continuing to work with radiation. Like a canary in the mine, darkening of strips of photographic film worn by scientists and engineers indicates a high level of radiation.

Born from a deadly combination of human error, lax attitudes to safety and poor design, the Elephant’s Foot remains a hazard. It is still hot and continues to eat through its surroundings. Should it penetrate further and reach water supplies, Chernobyl could once again rear its head as a major health emergency.

‘Til next time…

Joe

Are you interested in reading about the untold stories of the Liquidators of Chernobyl?
I recommend reading Voices of Chernobyl by investigative journalist Svetlana Aleixievich, winner of the 2015 Nobel Prize in Literature.

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