chernobyl-Nuclear-Power-plant

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26 апреля 1986 года произошла авария на Чернобыльской АЭС. Украинская ССР, СССР.

Chernobyl disaster occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in the Ukrainian SSR, USSR.

The Pripyat Amusement Park is an amusement park in the ghost town of Pripyat, Ukraine. It was to be opened 1 May 1986 in time for May Day celebrations, but the Chernobyl disaster occurred on 26 April 1986 and the city of Pripyat was subsequently evacuated. Pripyat remains abandoned to this day.

Radiation levels around the park vary; the liquidators washed radiation into the soil after the helicopters carrying radioactive materials used the grounds as a landing strip, so concreted areas are relatively safe. However, areas where moss has built up are dangerously high; some areas can emit 25 µSv/h, among the highest levels of radiation in the whole of Pripyat.

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Pripyat: A City Frozen In Time (1 of 2)

On April 29th, 1986, three days after the disaster at the Chernobyl Nuclear Power Plant, the government decided to evacuate the nearby city of Pripyat. At the time, Pripyat, which had only been founded 16 years earlier for workers at the plant, was home to nearly 50,000 people. The residents were told they would only be evacuated for a short time, however, despite efforts to clean up the radiation, it has remained unsuitable for human life.

Today, Pripyat stands as a modern day Pompeii, frozen in time by a catastrophic disaster. It is a city of radioactive ruins, slowly being reclaimed by the forest it had displaced. Cold war era posters still adorn the walls of public buildings while children’s’ notebooks remain on their school desks. The Ukrainian government has forbade visitors from entering any of the buildings due to their structural instability, but as my friend and I booked a private tour, our guide was willing to take us into several structures, including two schools, a kindergarten, the palace of culture, the gymnasium, a 16 story apartment building, and the city hospital.

Because the buildings were sealed following the disaster, radiation levels inside the buildings are negligible. Outside, however, countless hotspots remain. At one point, armed with a Geiger counter, I came across beta radiation 220X the level considered suitable for human life. It was exciting…until I considered the implications. Shortly thereafter, we left the ruins and returned to the modern world. 

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After the disaster in Chernobyl’s Reactor #4, radioactive smoke was pouring out of the damaged building, suggesting to scientists that the reactor’s graphite core was on fire. To try to quell the radiation emitting from the core and the graphite fire, several thousand tons of neutron absorbers were dropped from helicopters into the reactor building. Despite the sacrifice the helicopter pilots made (most died within days), it was clear that almost none of the material landed in the core. On 6 May 1986, the smoke and radiation emissions stopped inexplicably. 

Scientists now knew something had happened in the core, but weren’t sure what. The explosion in the reactor threw its 2,000 ton lid into the air. It fell on edge and into the mouth of the reactor and sent chunks of the core scattering. Desperate for information, scientists were sent into the basement of Block 4, searching in rooms despite knowing the reactor could very well have exploded again. A crude, wheeled camera was set up to be sent into areas of extremely high radiation, and scientists eventually discovered a huge mass of sand and nuclear fuel that had fused together, but no one knew where it could have come from as it was deep in the basement. The decision to find a way to inspect the reactor was made.

Holes were drilled in a room adjacent to the reactor so workers could have a better look at the inside. Several theories of what they might find were discussed, but they were all certain of one thing: There would be damaged reactor core. What they found confounded all expectation. The reactor was completely empty. The entire structure of the core had seemingly vanished. 

The decision to continue the hunt for nuclear fuel with humans rather than robots was made because the ferocious amounts of radiation beneath the reactor rendered robots sent to assess the damage useless. Scientists first found concrete, steaming from the heat of nuclear fuel below it. It was then that they saw the lava - a molten mixture of portions of nuclear fuel, fission products, structural materials from the affected part of the reactor, and molten concrete called corium.. Scientists now knew that much of the fuel had escaped the reactor in this manner. It had accumulated in a room beneath the reactor until it reached the edge of the relief valves, then migrated downward to the Steam Distribution Corridor. The corium also flowed to several other places, like the Steam Distribution Channels and Pressure Suppression Pools.

Uranium content in the corium is easily identified in the photos above by its yellow color. The 4th photo is of the notorious Elephant’s Foot.

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Чернобыльская катастрофа. 26 апреля 1986 года.

Disaster at Chernobyl. April 26, 1986.

The ghost town of Pripyat in November, inside the exclusion zone in Chernobyl.

The Chernobyl disaster (locally Ukrainian: Чорнобильська катастрофа, Chornobylska KatastrofaChornobyl Catastrophe) was a catastrophic nuclear accident that occurred on 26 April 1986 at the Chernobyl Nuclear Power Plant in Ukraine (then officially Ukrainian SSR), which was under the direct jurisdiction of the central authorities in Moscow. An explosion and fire released large quantities of radioactive contamination into the atmosphere, which spread over much of Western USSR and Europe. . It is widely considered to have been the worst nuclear power plant accident in history, and is one of only two classified as a level 7 event on the International Nuclear Event Scale (the other being the Fukushima Daiichi nuclear disaster).

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The reactor’s fuel rods melted and made its hasty escape through the bottom of the reactor, taking the fuel claddings, molten serpentine and molten concrete with it. 

The lava separated into three individual streams as it flowed from the remains of the reactor. The first stream gathered into a layer on the floor of the steam distribution corridor. From there it flowed through the stream distribution channels right into the pressure suppression pools. The second stream entered through the opposite side of the steam distribution corridor. The third flowed to other areas under the reactor.

The most famous example of corium at Chernobyl is the “Elephant’s Foot,” a mass that consists of two metric tons of lava, which gets its name because it literally was in the shape of an elephant’s foot, although I believe degradation over the years has changed its shape.

In the photos labeled with numbers, the number one denotes where the corium in that particular area settled. The last two are of the Elephant’s Foot. 

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Chernobyl Disaster - Chernobyl Nuclear Power Plant - Pripyat, Ukraine

April 26, 1986 - Disaster strikes. A sudden and unexpected power surge in Unit 4 occurred during a systems test.

01:23:40 - Emergency shut down fails. When the shut down was attempted, an exponentially larger spike in power output occurred. This led to a reactor vessel rupture and a series of steam explosions.

01:23:44 - The reactor in Unit 4 runs out of control. Two explosions destroy Unit 4’s core, and the roof of the reactor’s building. The resulting fire disperses radioactive material high into the atmosphere. 

01:28:00 - The first group of 14 firemen arrive on the scene to attempt to extinguish the fires. 

May 6, 1986 - The initial fire in Unit 4 is finally controlled, 10 days after the disaster began. 30 military helicopters flew over the reactor, dropping 2,400 metric tons of lead and 1,800 metric tons of sand to try to smother the fire and absorb the radiation.

May 20, 1986 - Work hastily begins on the sarcophagus (“Shelter Object”) for Unit 4. This massive structure of more than 7,000 tons of metal and 400,000 cubic meters of concrete is meant to confine radioactive material from the destroyed reactor. Roughly 90,000 workers complete its construction in 206 days.

December 15, 2000 - Despite the disaster, the plant’s remaining three nuclear reactors continued to run for years. On December 15, 2000, the last reactor in operation was shut down.

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“There were 3,823 of them. This number I will retain in my memory for the rest of my life.”

‘Liquidator’ is the generic name given to civil and military personnel in the former Soviet Union called upon to handle the consequences of the Chernobyl accident in 1986. They are credited with not only limiting damage from the disaster itself, but averting a greater catastrophe, which was expected if the melted, lava-like nuclear fuel that had escaped the reactor would have melted through the basement floor and came in contact with groundwater, triggering a massive steam explosion.

Most Soviet-time liquidators were coerced to work for a certain, medically reasonable time by means of direct order, motivation, and information on the operation’s life-threatening occupational hazards (including exposure to radiation and hazardous materials and severe stress) being withheld from them. However, thousands of liquidators volunteered of their own accord to participate or to extend their work beyond the initial compulsory term. 

The worst of the radioactive debris was collected inside what was left of the crippled reactor, much of it shoveled in by liquidators wearing heavy protective gear, often assembled by the liquidators themselves as they were not properly equipped to take on this daunting task. They were dubbed “bio-robots” by the military because the robots they initially attempted to use were disabled by the extreme levels of radiation, and it was decided that the only way to go about this was to use humans. 

Nikolai Tarakanov, the general in charge, gave them the following orders: “Now my dear comrades, you’re to go in teams of four, not six. You’ll be given one minute to complete the following mission. Look at your colleagues [pointing to a set of televisions displaying closed-circuit footage of other bio-robots cleaning up debris], they’re running quickly through this opening and then around the corner. You will be accompanied by a lieutenant along the wooden platform, and there’s the operational area. There you’ll find some blocks weighing 40 to 50 kilograms each. Is that clear? Each soldier must take 4 blocks [with their hands]. Carry the 4 blocks to the pit and throw them in, but you mustn’t go too near the edge of the pit. Only as far as this steel railing. They’re doing it correctly - do you see? Are you with me?”

Viktor Popov, a Russian theoretical physicist, was asked in an interview with BBC Horizon, “If anyone had said to you five years ago that you would have to work in areas of radiation - 200 Roentgens, would you have believed them?” He replied, “No, no. This is no place for people - 200 Roentgens, absolutely not. The problem is that we do not have the necessary technology to let people work safely in these conditions, I’m sorry to say. It would be better to ensure that such a catastrophe never happens, then we wouldn’t have to work in such high levels of radiation. But now there’s no alternative. And we know it’s not doing our health any good. Somehow the problem has to be solved - there’s no way around it. In time of war, things are also bad… Bullets are flying around. It’s better to sit at home, but someone has to go to war. This is a similar situation.”

Because of the dissolution of the Soviet Union in the 1990s, evaluating the liquidators’ health is difficult, since they come from various countries. All the figures quoted by various agencies are controversial, although an UNSCEAR report places the total confirmed deaths from radiation, as of 2008, at 64.

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After the massive fire on the roof of Reactor #4 was contained, the Soviet government was now burdened with the difficult task of debris removal and cleanup. The explosion caused the reactor to eject large chunks of its graphite moderators, some with control rod channels still intact, nuclear fuel and other radioactive material onto its roof, and a large amount of debris landed on the roof of the power plant’s 3rd reactor building. 

Initially, workers attempted to clear the debris with foreign robots, but naturally, the robots were no match to the extreme radiation levels and so, the Soviet government employed the use of reservists, referred to as liquidators and “Bio-Robots.” Given the extreme levels of radiation, liquidators worked in very small shifts. They were allowed only 40 seconds to shovel up debris and throw it off the roof. Any more time spent on the roof would expose them to the maximum dose of radiation a human being should receive in their entire life. In addition to manually removing debris from the roofs, the Soviet government sent helicopters to the power plant to drop bags of sand, lead and boric acid into the reactor itself to smother the radiation leaking into the atmosphere. Over 5,000 metric tons of material was dropped, but later inspections reveal that most of the material landed inside the building, but not in the reactor core itself.

Photos 1 & 2: Robots initially used to clear debris and were rendered useless, greatly effected by extreme radiation.

3rd Photo: “Bio-Robots” suiting up for debris removal excursions. The Soviet army did not have adequate uniforms adapted for use in extremely radioactive conditions, so anyone enlisted for cleanup had to cobble together their own uniforms made from lead sheets.

4th Photo: “Bio-Robots” climbing the ladder to the roof of Reactor #3’s building to clear debris.

5th & 6th Photos: “Bio-Robots” clearing debris.