One big incident that left an un-erasable traces in the history.

1. Chernobyl Disaster
Presenter:
Sheikh Jalal Sajid

2. Background
• Happened on April 26, 1986 at 1:23a.m.
• Has been called the biggest socio-economic
catastrophe in peacetime history
• 50% of the area of Ukraine is in some way
contaminated
• Over 200,000 people had to be evacuated and
resettled
• 1.7 million people were directly affected by the
disaster

4. Contents
•How it happened
•Immediate crisis management
•Impact of disaster:
• Socially
• Evironmentally
• Economically

5. Accident in Reactor-IV
Reactor crew preparing for a test to determine how long
turbines would spin and supply power following a loss of
main electrical power supply
Plants known to be very unstable at low power settings.
Disabling of automatic shutdown mechanisms,
preceded the attempted test early on 26 April.

6. As flow of coolant water diminished, power output
increased.
When the operator moved to shut down the reactor from
its unstable condition arising from previous errors, a
peculiarity of the design caused a dramatic power surge.
The fuel elements ruptured and the resultant explosive
force of steam lifted off the cover plate of the reactor
Releasing fission products to the atmosphere

7. Second explosion threw out fragments of burning fuel and
graphite from the core and allowed air to rush in
Causing the graphite moderator to burst into flames.
Over 1200 tons of Graphite - burned for 9 days, causing
the main release of radioactivity into the environment.
A total of about 14 EBq (1018 Bq) of radioactivity was
released, half of it being biologically-inert noble gases.

8. Summary

10. i. Fighting the Fire
The fire brigade of Pripyat was able to extinguish all the fire, except
the graphite fire inside Reactor 4.
The fire inside Reactor No. 4 continued to burn until 10 May
1986.
Eventually, the graphite fire was extinguished by using
sand, boron, dolomite, clay and lead from airdrops onto the
burning reactor by helicopter.

11. ii. Evacuation
The nearby city of Pripyat was not immediately evacuated.
- a government committee was formed to investigate the accident.
The evacuation was begun a day after the explosion, as
the committee faced with ample evidence of extremely
high levels of radiation and a number of cases of radiation
exposure.

12. iii. Sarcophagus
Even after the fire had been
extinguished, radioactive particles were
still escaping from the reactor core
itself.
The Soviets devised a plan to cover
the entire reactor with a shell that was
to be able to exist forever. The shell
was deemed the Sarcophagus.
Within it, there is about 200 tons of
highly radioactive material which poses
an environmental hazard until it is
better contained.

13. Chernobyl before the
accident
Chernobyl at the time of the
accident
Chernobyl with the
Sarcophagus around
Reactor Number 4

14. Figure: The Chernobyl nuclear plant apparently after they started
to build the sarcophagus in the aftermath of the disaster.

15. • At first, robots were sent for this task.
• But their transistors did not work in that radioactive
environment.
• Then volunteers were sent for the task.
• But they were allowed to stay for 90 seconds or less in
the reactor otherwise their nervous system could break
down.
• The decontamination took place from the beginning May
till the end of Winter 1986.
• Every movable objects around the plant were burried.
iv. Cleanup Efforts

16. About 60,000 buildings had to be
washed with special chemicals,
and even some roofs had to be
replaced.
Special chemicals were
sprayed on streets to
immobilize radioactive
particles.

18. The explosion at Chernobyl acted like a
volcano, blowing radioactive particles far into
the sky.
(a) International Spread of Radioactivity
Wind moved the plume, or cloud of
radioactive particles, all around the world.
Even worse, when the plume passed by
several countries, it began to rain, and
nuclear fallout hit the ground.
Large areas of Belarus, Ukraine, Russia and
beyond were contaminated in varying
degrees.

19. (b) Health of Plant Workers
According to Ukrainian health ministry
officials, 125,000 people were reported dead
as a result of the accident.
In the aftermath of the accident, 237 people
suffered from acute radiation sickness. Most
of these were fire and rescue workers trying
To bring the accident under control
Two people died in the initial steam
explosion, but most deaths from the
accident were attributed to radiation.
135,000 people were evacuated from the
area, including 50,000 from Pripyat.

20. (c) Delayed Health Effects
One of the most delayed effects of the radiation is the induction
of Cancer especially amongst those Russian liquidators who
were exposed to more than 150 mSv.
The people in the area of contamination have suffered a
paralyzing fatalism.

21. The radioactive contamination of aquatic systems therefore became
a major issue in the immediate aftermath of the accident.
(d) Residual Radioactivity In The
Environment
Rivers, lakes and reservoirs
The Chernobyl nuclear power plant lies next to the
Pripyat River which feeds into the Dnieper River reservoir
system, one of the largest surface water systems in
Europe.

22. Flora and fauna
(i)Flora
• After the disaster, four sq. km of pine forest in the immediate
vicinity of the reactor turned ginger brown and died, earning the
name of the “Red Forest”
• Local pine trees grew huge pine cones, with needle-like leaves
10 times heavier than normal.
• Some fruits and vegetables also turned oddly shaped
eg; potato, tomato etc.

23. (ii) Fauna
• Radiation has affected animals living near the site of Ukraine's
Chernobyl nuclear disaster.
• A major effect on the livestock was mutation.
• The livestock was culled and buried.

24. (f) Cost
And about US$400 Million was spent on improvements to the
remaining reactors in Ukraine enhancing their safety.
The total costs including cleanup, resettlement, and compensation
to victims has been estimated to be roughly US$200 Billion.
In the 1986 to 1989 industrial and agricultural losses and insurance
payments estimating US$36 Billion were spent during this period

26. • Today, Pripyat and the surrounding area are not
safe for human habitation.
• The radioactivity in the damaged reactor would
need to be contained for 100,000 years to ensure
safety.
• However, the sarcophagus was designed to last for
only about 30 years.
• This would be a tough challenge not only for today,
but for many future generations.

27. Any Questions??