this is a presentation about the chernobyl accident

1. The Chernobyl Disaster
by Sebastian, Ilya and Milan

2. introduction
The Chernobyl disaster was a catastrophic nuclear accident that occurred on April 26,
1986, at the Chernobyl Nuclear Power Plant in the city of Pripyat, Ukraine, then part of the
Soviet Union. It was the result of a combination of human error, design flaws in the
reactor, and a lack of safety measures.
The disaster occurred during a routine test of the plant's reactor number 4, which went
out of control and exploded, releasing a huge amount of radioactive material into the
atmosphere. The explosion caused the reactor's graphite moderator to ignite, creating a
fire that burned for 10 days and spread radiation over a wide area of Europe.

3. The power plant
The construction of the ChNPP started in 1972 and the reactors started entering
commercial operation between 1978 and 1984. They produced 10% of all Ukraine’s
electricity. If the disaster wouldn’t happen the power plant would have 12 reactors.
Each reactor at the Chernobyl plant was a type of nuclear reactor called a
RBMK-1000, which was designed and built exclusively in the Soviet Union. The
RBMK-1000 reactors were graphite-moderated, water-cooled reactors, which were
larger and more powerful than most other nuclear reactors in operation at the time.
The Chernobyl plant was a flagship project of the Soviet nuclear industry and was
seen as a symbol of Soviet technological prowess. However, the design of the
RBMK-1000 reactors at Chernobyl had several design flaws, including a lack of
containment structures and safety features that made them vulnerable to accidents.

4. the accident
The Chernobyl accident occurred on April 26, 1986 at the Chernobyl Nuclear
Power Plant in Ukraine, then part of the Soviet Union. During a routine test of
reactor number 4, operators initiated a series of errors that resulted in a
nuclear chain reaction that went out of control.
Design flaws in the reactor, including a lack of containment structures, led to
a steam explosion and subsequent graphite fire that burned for 10 days,
releasing a large amount of radioactive material into the atmosphere. The
explosion and fire immediately killed two workers at the plant, and 28 more
died within weeks of acute radiation sickness.
The release of radiation forced the evacuation of more than 100,000 people

5. It is unknown if it was their fault that the power out of the plant falls too much at 28 minutes
past midnight on April 26. They tried to increase the power but something is wrong, theyve
never seen this before. This is partly because there’s been a buildup of Xenon during the test.
Its not important to know what Xenon is but when there is too much of it it can cause Xenon
poisoning. It would usually burn away when the reactor is running at full power, but the
slowdown has caused a buildup, and the buildup has caused a further slowdown. That’s a
dangerous loop. It’s because of this over abundance of Xenon that even when they take most
of the control rods out they still can’t get enough power. They shouldn’t have done this. One of
the new operators gets on the phone and asks: “What shall I do? In the program, there are
instructions of what to do, and then a lot of things are crossed out.” The worker on the other
end pauses and then says: “Follow the crossed-out instructions.” They got the power
stabilised, but the shift supervisor, Anatoly Dyatlov, doesn’t think it’s enough. One day he will
lie that he want in the room when mistakes were made, but he was. The reactor is certainly
running at a lower power than is safe for a test, but they carry on anyway on the orders of
Dyatlov, he doesn’t want his reputation to be ruined after another failed test. At 1:24:04 AM the
test really starts, meaning they’re going to simulate a power outage and test the turbines and
generators. This is when all hell breaks loose. What happens is a sudden, serious and massive
increase in power. So serious that someone hits the SCRAM button. At the ChNPP , this was
the AZ-5 button. Its an emergency off-switch that makes all of the control rods drop down to
stop the nuclear reactions. But because of a design flaw there is a huge surge reactivity, the
operators dont know what they have done. The heat creates a massive amount of steam, so in

6. effect of the radiation
The reactor's design flaws, including a lack of containment structures, led to a steam explosion
and subsequent graphite fire that burned for 10 days, releasing a large amount of radioactive
material into the atmosphere. The explosion and fire killed two plant workers immediately, and 28
more died within weeks from acute radiation sickness.
The radiation release forced the evacuation of over 100,000 people from the surrounding area, and
an exclusion zone was established around the plant to prevent further contamination. The disaster
had long-term health and environmental effects, with many people suffering from radiation-related
illnesses and increased rates of cancer and other diseases in the affected areas.

7. health impact
The Chernobyl nuclear accident, which occurred on April 26, 1986 in Ukraine, had a significant
impact on both the immediate and long-term health of the population. The initial explosion and
subsequent fires resulted in the release of large amounts of radioactive material into the
environment, causing acute radiation sickness and death among first responders and workers who
were present on site. According to official reports, 31 people died in the first weeks of the accident
as a direct result of the blast and radiation exposure. However, the long-term health impacts of the
accident are much more difficult to quantify. The release of radioactive material contaminated the
surrounding environment, and people who were exposed to radiation are at increased risk of
developing cancer, especially thyroid cancer. The accident also had a significant psychological
impact on the affected population, as many people were forced to evacuate their homes and leave
their communities.

8. enviromental impact
The Chernobyl nuclear accident, which occurred on April 26, 1986 in the Ukraine, had a
significant environmental impact on the surrounding area and beyond.The explosion and
subsequent fires at the Chernobyl nuclear power plant released large amounts of radioactive
materials into the atmosphere. The wind carried the radioactive particles over a wide area,
contaminating the soil, water, and vegetation.The immediate impact on the environment was
severe. The explosion and fires killed trees and other vegetation in the surrounding area, and the
released radioactive material contaminated the soil, water, and air. The explosion also damaged
the reactor building, which released large amounts of radioactive dust and debris into the
surrounding area.The long-term impact on the environment is still being studied, but there is
evidence of continued contamination in the area. The soil, water, and vegetation in the immediate
vicinity of the Chernobyl site are still contaminated with radioactive isotopes, such as cesium-137
and strontium-90. These isotopes have long half-lives and can remain in the environment for
many years.

9. conclusion
The Chernobyl accident was the worst nuclear accident in history, and its impact on nuclear safety
policy, the perception of nuclear power, and the environment has been profound. It has led to
improvements in reactor safety and emergency response, as well as increased scrutiny of the
nuclear industry and its practices.

10. thanks for your attention