I'm quite sure that every person who is reading this right now is familiar with what happened at the Chernobyl nuclear power plant.
Here is a short summary, for those among you who come along this blog by coincidence, or would like to refresh their memory.
On the 26th of April in 1986, at 1:23AM (Kiev time zone) two big explosions occurred at the Chernobyl power plant (V.I. Lenin) 40-60 seconds after a test at the plant had started.
A system test, which was ordered by the soviet government, was planned in the night of the 25th of April by the plant staff.
This test was meant to clarify whether the nuclear reactor would have been able to keep the cooling water circulating in case of an emergency shut down.
In order to do so, the turbines and pumps should have generated the needed power to overcome the time until the start of the emergency generator.
BUT there was a design failure known for this type of reactor (RBMK) which left the installation without the supply of cooling water for about 75 seconds, in case of an emergency shut down.
This gave „enough “time to evolve the heat which did lead to the catastrophic failure.
By virtue to this kind of test the automatic shutdown system needed to be deactivated because every working control system would have recognised this test as a problem and an alarm would have been set off.
Actually, the test should have been carried out before taking the reactor into operation. Due to staff problems and the „urge “to finish the construction earlier than expected, this test was skipped!
Additionally, this test should have taken place one shift earlier. Therefore the delay resulted in unprepared / unsuitable / not trained / ,,, staff carrying out the test.
At 1:23 AM the test started.
The main turbine got shut down which started another issue: The turbine had way less torque than expected which caused a high steam evolution due to not enough cooling water being in the reactor.
Above lead to a high reactor performance that the control system tried to avoid with adding control rods.
Due to the higher amount of energy emerging, more water was transformed into steam in the core which provoked a chain reaction.
„Luckily“ the automatic control system could „successfully“ contract the chain reaction with using one control rod after another until it used all 12. Those control rods were not under manual control.
Around 1:23:30 the emergency shut down was activated: The AZ5 button.
The exact reason is not known but most assume that this was a reaction to the even higher power levels which evolved on the base of the chain reaction.
This high-power level caused retracting the manual control rods additionally to the automatic ones above, which needed estimated 18 seconds.
These days it's known that also the control rods were designed with a mistake. The rods inserted by pushing the AZ5 button had a graphite tip, not the neutron uptake cooler used in standard rods, with neutron absorbing boron.
The core overheated and fractured the fuel rods, that blocked the control rods after 1/3 of the insertion.
The energy production went up to 530MW in just a couple of seconds.
The steam pressure raised extremely high as a result, wherefore radioactive material leaked into the cooling water and the channels of the fuel elements were wrecked.
Suddenly the energy production skyrocket to 30GW - this is ten times higher than usual!
The last measured energy level visible on the control panel showed 33GW.
This sudden raise resulted in an uncontrolled increase of the steam pressure with fatal consequences.
An explosion did tear off the 1500 tons heavy reactor cover and pushed it through the roof of the reactor building. This caused the destruction of more fuel rods and several cooling lines of the core, which again emerged a further raise of the thermal power level/production.
Three seconds later a second explosion, triggered by the heated up fuel rods being exposed to oxygen(air), occurred.
Thereby parts of the reactor spread over a huge area which was discovered only at sunrise the next morning.
The wind starts turning it´s direction which carries radioactive cloud north-west.
Around 4:30AM Akimow(power plant provider) is communicating that the reactor is intact and just need to be cooled. This of course wasn´t true.
The Soviet Union didn´t communicate at all what has happened at the plant also due to the reason that they government was 100% informed about what happened.
A couple of hours later Sweden realized a raise in the radioactivity in their environment so they got back to the soviets and started asking question.
A couple of moments later the fire department was alarmed: Fire fighters from the power plant, the town Pripyat and Chernobyl were recruited. In total 42 men.
In the morning of the 26th of April fire fighters tried to put off the fire with pumping water into the reactor what failed.
While also trying to put the fire off from the outside, the helper started recognizing that soot was falling from the sky.
But by that time, they didn’t know that this soot was highly radioactive as well as the graphite pieces which were lying next to the reactor.
The radiation is now 30-40 times higher than the radiation which was released by the nuclear bombs of Hiroshima and Nagasaki together.
Even though the plant got its name from the small-town Chernobyl, the government built another town which was located 2km away from the plant called: Pripyat.
Built in the 1970´s just for the power plant worker and their families, while it was planned to make Chernobyl the biggest operating power plant in the world with 12 reactors in total.
Pripyat was a model town of the Soviet Union which average age was around 26 years at the time of the accident.
As consequence of the accident Pripyat was exposed to high level of radiation.
During the whole day (26th of April) after the accident, 50.000 people weren´t informed by the government about the radiation dangers neither did they receive iodine pills to contract the effects of the radiation.
A couple of hours after the accident the radiation level in Pripyat was 20.000 times higher than usual.
Even though soldiers or military staff was attending, they left the inhabitants unsuspecting.
Just on the 27th of April around 2PM the order to evacuate was given.
At first, women and children were collected. But the Soviet Union didn’t had enough busses in this region. So, busses and trains from other parts of the country had to come over to evacuate the 50.000 inhibitions of Pripyat.
The line of busses to Pripyat was 25km long.
To start of the evacuation the government told the inhabitants to just take their most important belongings because the evacuation „wouldn’t take longer than 3 days “.
So, most of them just collected official documents like passports, a bit of clothing and one toy the keep their kids calm.
Overall the evacuation did take place calmly and organized. The government kept insisting that they did communicate lees to avoid a mass panic.
Officially 600.00 people were affected by the nuclear accident. The documents are dividing the victims into different categories.
The biggest category is made of 200.000-240.000 saviours, soldiers, policemen and fire fighters which tidied up and contaminated at the plant and the surrounding.
Furthermore there´s a group of 116.000 inhabitants of the area surrounding Chernobyl.
Further 200.000 people were evacuated later in the affected areas of Belarus, the Ukraine and Russia.
Even though 5 million people were still living in areas which were affected by the nuclear accident.
After the nuclear accident occurred a radioactive mess had to be cleared up.
Over all 800.000 people attended in this process. First just the plant staff and the fire fighters. Later, also soldier and workers.
134 of them were so heavily contaminated that they were suffering from radiation sickness.
The estimated number of deaths over the years lays around 2.200 people.
None of the liquidators was informed about the radioactivity they were exposed to especially not the fire fighters.
They didn’t wear any protection clothes due to the fact that the emergency caller was just informed about a simple fire. Not about the reactor core being open.
One task besides putting off the fire in the liquidation process was to tidy up the roof of reactor building number 3.
First the army/ government/ scientists sent robots on the roof which should have cleaned up.
They were operating for a couple of moments but then started to fail due to the high level of radiation.
This was the reason why the responsible sent humans on the roof. They were collecting the radioactive debris and threw them back into the ruin of reactor number 4.
The workers were just allowed to stay 45 seconds on this roof due to the radiation levels being extremely high and lethal. The only protection they had was a lead shield/ vest, a gas mask and gloves.
But the dangerous work had to be done on the basis of another explosion being possible. The fall-out of this third explosion would have made the biggest parts of middle and eastern Europe being uninhabitable.
Now the most important part in the liquidation process:
3 brave man had to dive under the plant because its basement was mostly flooded.
They were called the “suicide squad “.
Just one man who was available by that time knew the location to release the collected water. One of the plant engineers named Alexei Ananenko.
Alongside with Valeri Bezpalov and Boris Baranow, was carrying out the order.
They had the chance to refuse the mission but they „luckily“ didn’t do so.
Those 3 men released the valve in time. With doing so they saved the world from a disaster that would have been exponential.
By the time all three men surfaced under the reactor, they were showing signs of radiation poisoning.
The possibility would have been big, if they failed, that reactor number 3,2 and 1 also would explode under the eruption of a new explosion from reactor number 4.
The last task of the liquidation process was the following:
Miners were recruited to dig a tunnel underneath reactor number 4 within just a couple of weeks.
If the reactor core would have melted to the cooling water or ground water located underneath the reactor it would have contaminated the ground water for the whole region surrounded.
The miners did as well wear protective clothes. But they were avoiding to wear it caused by the heat underneath the reactor.
Most of them didn’t wear shirts. Just pants, gloves, a hat and a mouth cover.
When the tunnel was finished it was filled with concrete.
All liquidators which died within a few weeks were buried in lead coffins which were covered by concrete to not expose too much radiation coming from their bodies to the environment.
With exception of the ex-inhabitants which are visiting the graves yards or those who are visiting Chernobyl as tourists, around 140 people are still living in the exclusion zone.
Most of them are old and „retired “.
Besides that approximately 3000 workers which care for the zone are still living there. Almost the same amount of people is still working in the power plant (of course not active anymore) but living in a town called Slavutych. Most of them are living in the zone for 2 weeks and then leave it for 2 weeks to come back again for the same amount of time.
Pripyat nowadays is an abandoned ghost town bust still spreads its own charm and atmosphere.
It was one of the least towns which wasn’t tore off. Those which were tore off can just be reminded by their place signs next to the streets.
Pripyat and the 30km exclusion zone are guarded by the police and the army, even though looting and robbery still cant be avoided.
Most of it took place in 1991 after the collapse of the Soviet Union.
The whole town was looted and there is not a single apartment which was not haunted by thieves.
One military factory called Jupiter was still in operation in 1997 but is nowadays even more destroyed than most abandoned apartments or schools in town.
The town is full of contemporary regulation signed, books and pictures which mostly are signs of Lenin. They´re everywhere: In the culture place, the hotel, the hospital, the police station as in the kid gardens and schools.
A walk through Pripyat is like a throw back in time with only one difference: no humans and not even a single bird on the sky.
Chernobyl is a good example to see how nature takes all back. It is unique!
Source of all pictures on this side: google.com