The Chernobyl Nuclear Disaster

“For the first time ever we have confronted in reality 
the sinister power of uncontrolled nuclear energy”

Mikhail Gorbachev — President of Soviet Union

Overview

The Chernobyl Power Plant in Chernobyl, Ukraine was nuclear-fission-powered and was capable of producing four times the power output of the Huntly power station.

However at 1:23 am on the 26th of April 1986 a failed reactor test resulted in the world's worst nuclear disaster, subsequently displacing over 200 000 people, and instantly killing a further 54 residents and emergency workers.

The Disaster

Your Geiger counter is beeping like mad. The radiation levels are extremely high, we mustn't stay for long. This is the centre of the disaster zone responsible for the immediate deaths of 54 people, 4 000–24 000 who will eventually die, and the thousands more affected by the effects of radiation. Through this section, I'll give a brief run–down of the events leading up to the disaster, the aftermath and the immediate events which followed. Quick, get reading…

 

The events leading up to the disaster

25 April 1986, 1:00 pm

Anatoly Dyatlov (a deputy chief engineer) was preparing to run tests on reactor 4, testing the effects of running the reactor at low power. Control rods were lowered into the reactor, slowing the reaction to half-power.

25 April 1986, 2:00 pm

The next stage was to disable the emergency cooling system. Disabling it breaches the most fundamental of safety protocols.

An electrical official from Kiev (the third largest city in the Soviet Union) was concerned the city would run low on power and requested testing to be resumed at night when the city's power consumption would be lower.

25 April 1986, 11:10 pm

The go-ahead to resume was given. The reactor was slowed once again, this time to the lowest operating power.

26 April 1986, 12:00 am

Engineers noticed the reactor was gradually slowing — It was heading towards shutdown. Anatoly Dyatlov, angry, ordered control rods to be lifted to speed up the reaction. The power levels rose, which started the water pump, causing the water around reactor to be drained. Without water, the reactor began to overheat.

26 April 1986, 1:23 am

Tremors are felt. Suddenly, there was a huge surge in power. In a panic, all the control rods were lowered. The rods jammed, and following that a large explosion occured.

The controls seemed to no longer function. Four engineers ran up to see the aftermath from the roof and saw "the world's worst nuclear disaster". The concrete shield had been uplifted by the pressure of the steam, air rushed in and started an enormous blaze. 50 tons of radioactive particles were expelled into the atmosphere.

 

 

Fighting off the flames

When the local firemen arrived, they were blown away by the scale of the disaster, more firemen were needed. 186 firemen and 81 fire engines came to fight the blaze. However, they did not realise that this wasn't a typical fire which could be put out with water; furthermore, they were unaware of the invisible danger of radiation. By 6:30 am, the fire was still raging. Radiation sickness was evident among many. They felt tired and began to vomit. Gums begun to bleed and their teeth and hair began to fall out. Their skin started to bruise and bleed. Most unfortunately died.

fire fighters

[Left] Monument to all the firemen who risked their lives
[Right] Fire engines used in the operation

The radiation was too high… I started to feel tired, I felt sick. My body and face were glowing…

Boris Aleshaev — Firefighter

 

plant flame

[Left] Aerial view of aftermath
[Right] Helicopter dropping material to quench the flames

The following day

Everything seemed normal. People were walking about normally, and "there were children everywhere". The remaining 3 reactors continued running. Workers came in to work, sceptical at the state of the site, however were reassured that everything was under control.

The government was also fed the same message. Despite this, they flew experts from Moscow to assess the site. The fire burning at 2500°C was estimated to continue burning for weeks and even months. There was a decision to bury the fire in clay, sand, lead and boron.

A conspiracy

People became suspicious and nervous after hearing about the symptoms the firemen were experiencing. No one was told what had happened. Children were given iodine tablets (which protect the body from some harmful types of radiation). Later, policemen ordered people to stay indoors with their windows shut. Still, no one was told why.

The evacuation

Radiation was considered extremely high and dangerous. There was15 000 times more radiation than what a normal person experiences in a year. The radiation released was equal to 100 – 1 000 nuclear bombs.

During the night, government officials ordered buses to evacuate people from Pripyat. On the 29th of April it was announced over the loudspeaker that "[an] unfavorable radiation situation had occurred".

Consequently, a 3 day evacuation was ordered. No one had any idea they were leaving for good.

A 10 km radius exclusion zone was setup and the remaining reactors were shutdown. 5 days later, the exclusion zone was increased to 30 km. Winds carried the radiation north as far as Sweden, 1 500 km away; international alarm bells begun to ring.

evacuation

[Top] Mothers and their children boarding a train
[Bottom] Convoy of buses

 

Post-Disaster

 

The liquidators

Robots were brought in from Germany to clean up the radioactive rubble strewn across the site; but the site was so contaminated with radiation that the robots experienced interference, and were unable to function. As a result, 800 000 humans were brought in as a substitute. These humans were known as liquidators. The radiation level was so high that no liquidator could work for longer than 90 seconds at a time.

Radioactive trees and soil were buried in large concrete tombs and vehicles used in the clean up were abandoned in a large vehicle grave.

liquidators

[Left] Liquidators removing rubble from the Chernobyl plant
[Right] Vehicles used in the clean up laid to rest in this vehicle grave

The sarcophagus

To prevent further contamination, a large concrete shell was built around the reactor. This is known as a sarcophagus — Latin for “stone coffin” — and took around 7 months to construct. Built in a hurry, corners were cut and it is now showing signs of collapsing. A second shelter has been proposed — a 8–9 year project costing an estimated $1.1 billion New Zealand dollars and has an estimated lifespan of 100 years.

Photos of the sarcophagus which entombs the damaged reactor

Photos of the sarcophagus which entombs the damaged reactor

mutations

Radioactive and mutated apple and mutated calf in Chernobyl

The effects on health

There have been at least 1 800 thyroid cancer cases of children who were between 0–14 years at the time of the disaster. Other health defects include premature births, mentally ill children and children with birth defects. Additionally, many were also psychologically affected, turning to drinking and suicide.

Environmental impact

Besides the effects on humans, the Chernobyl disaster also dramatically affected the environment with 150 000 km2 of land contaminated with radioactive material. Mutations in both plants and animals were evident — Leaves changed shape and some animals were born with deformities. Despite this, rare species of moose, birds, beavers, wolves and boars have returned in the absence of humans.

Chernobyl today

The radiation levels have since receded at the Chernobyl power plant and it is possible to arrange day tours of the cities surrounding the Chernobyl plant. The villages and towns remain uninhabited by humans and it is evident nature is taking over many cities and villages. The lack of building and infrastructure maintenance has resulted in foliage growing on buildings and through roads and paths.

A lesson learnt

A hard lesson was learnt on the 26th of April 1986. In the following years, there was a heavier focus on nuclear safety and the safety design of the Soviet designed RMBK reactors (which was used in the Chernobyl power plant) was reviewed and amended. This disaster allowed for scientists to investigate the effects of radioactive pollution and the safest, most efficient clean-up procedure following a nuclear disaster — but most importantly, how to prevent such a disaster from every occuring again.

A classroom and cultural centre square consumed by nature

A classroom and cultural centre square consumed by nature



Short video by Carl Montgomery about his visit to Chernobyl