Download - Chernobyl disaster The worst manmade disaster in human history

Chernobyl Chernobyl disasterdisaster

The worst manmade disaster in The worst manmade disaster in human historyhuman history

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Where is Chernobyl?Where is Chernobyl?

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ChernobylChernobyl

• Built in Built in 1978-19791978-1979

• ChornobylChornobyl

23 May 2007Czech Technical University in

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Reactor Plant ScenarioReactor Plant Scenario

1.1. As the reaction occurs, the uranium As the reaction occurs, the uranium fuel becomes hotfuel becomes hot

2.2. The water pumped through the core in The water pumped through the core in pressure tubes removes the heat from pressure tubes removes the heat from the fuelthe fuel

3.3. The water is then boiled into steamThe water is then boiled into steam

4.4. The steam turns the turbinesThe steam turns the turbines

5.5. The water is then cooledThe water is then cooled

6.6. Then the process repeatsThen the process repeats

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Day of disasterDay of disasterPrior to the explosion the power was cut to the power station to stimulate a power failure. Emergency generators did power up to continue the flow of cold water to keep the nuclear fuel cool. However, because of the time delay between power failure and the generators kicking and because of a power surge once the generators did kick in overheating occurred leading to a series of explosions. It was reactor 4 that experienced the series of explosions releasing radioactive fuel and radioactive material into the atmosphere and surrounding area.

The radiation levels in the worst hit areas of the reactor building were estimated to be 5.6 roentgens (a unit of measurement for exposure to radiation) per second, which is the equivalent to more than 20,000 roentgens and hour. A lethal dose of radiation is around 500 roentgens over 5 hours, so in some areas workers received lethal doses in minutes.

• External fires around the plant were extinguished within 5 hours, but fires within the reactor continued until 10th May 1986. Helicopters were used to drop sand, clay and lead onto the reactor, but also firefighters on the ground were used. The firefighters were not warned about the dangers of radiation and most of them died later because of radiation poisoning.

Despite the massive radiation leak the nearby town of Pripyat was not evacuated for over 24 hours. The town had a population of around 50,000 at the time of the accident. When the evacuation warning eventually came, people were told that it would only be temporary and that they should leave all their belongings behind. However, a 30km exclusion zone still exists around the town, although some older residents have now chosen to move back.

•As well as causing a massive radiation leak around the plant, a radioactive cloud was also released into the atmosphere. The USSR authorities did not notify the world straight away of the accident and it was actually another power station in Sweden that first detected the cloud. The cloud contained 400 times more radioactive material than the Hiroshima bomb that hit Japan. All of Europe received fallout from the cloud, although it is estimated that up to 50% fell on Russia, Belarus and the Ukraine.

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Summary of FactsSummary of Facts• April 26, 1986:April 26, 1986:

– Chernobyl nuclear power Chernobyl nuclear power plantplant• Operator errors cause a Operator errors cause a

reactor explosionreactor explosion• Explosion releases 190 tons Explosion releases 190 tons

of radioactive gasses into of radioactive gasses into the atmospherethe atmosphere

• Fire starts that lasts 10 daysFire starts that lasts 10 days

• People:People: – 7 million lived in 7 million lived in

contaminated areas; 3 contaminated areas; 3 million were childrenmillion were children

• Wind:Wind:– Carries radiation far Carries radiation far

distancesdistances


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Radioactive falloutRadioactive fallout


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Direct CasualtiesDirect Casualties

• 5.5 million people still live 5.5 million people still live in contaminated areasin contaminated areas

• 31 people died in 3 months 31 people died in 3 months of radiation poisoningof radiation poisoning

• 1134 emergency workers 34 emergency workers suffered from acute suffered from acute radiation sicknessradiation sickness

• 25,000 rescue workers died 25,000 rescue workers died since then of diseases since then of diseases caused by radiationcaused by radiation

• Cancer afflicts many othersCancer afflicts many others• Increased birth defects, Increased birth defects,

miscarriages, and stillbirthsmiscarriages, and stillbirths


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Indirect CasualtiesIndirect Casualties

– By the year 2000 By the year 2000 there were 1800 case there were 1800 case of thyroid cancer in of thyroid cancer in children and children and adolescentadolescent

– High number of High number of suicide and violent suicide and violent death among death among Firemen, policemen, Firemen, policemen, and other recovery and other recovery workersworkers


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Environment ImpactEnvironment Impact

• Areas still Areas still impacted today:impacted today:– SoilSoil– Ground WaterGround Water– AirAir– FoodFood

• Crops Crops • LivestockLivestock


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Problems TodayProblems Today

• The SarcophagusThe Sarcophagus– After the disaster, a huge After the disaster, a huge

cement box was built around cement box was built around the radioactive materialthe radioactive material

– It is falling apart!It is falling apart!– According to a 2003 report by According to a 2003 report by

the Russian Atomic Energy the Russian Atomic Energy Minister, Alexander Minister, Alexander Rumyantsev, "the concrete Rumyantsev, "the concrete shell surrounding the shell surrounding the Chernobyl nuclear reactor is Chernobyl nuclear reactor is in real danger of collapsing at in real danger of collapsing at any time."any time."

– A new Sarcophagus is A new Sarcophagus is scheduled to be completed in scheduled to be completed in 20092009

Download - Chernobyl disaster The worst manmade disaster in human history

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