The Chernobyl nuclear disaster of 1986 in Ukraine was the worst nuclear power plant accident in history. When the reactor core was damaged during a safety test, it caused two explosions and released large amounts of radioactive material into the atmosphere. Over 100,000 people had to be evacuated from the surrounding area. Many people suffered long-term health effects such as increased cancer rates, and the environment was also contaminated over a large region. The accident highlighted issues with the Soviet nuclear reactor design and lack of safety precautions that led to the disaster.

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2. Nuclear Disaster
 By International Atomic Energy Agency (IAEA), The
Nuclear disaster is "an event that has led to significant
consequences to people, the environment or the
facility”.
The major Nuclear disaster is one in which the
reactor core is damaged and amount of radioactivity
are released such as Chernobyl Disaster.

3. Background
Chernobyl disaster April 26, 1986

4. CONTD
The Chernobyl disaster was a nuclear reactor
accident in the Chernobyl Nuclear Power Plant in
the Ukraine, which used to be a part of the Soviet
Union.
It is considered to be the worst nuclear power
plant disaster in history and the only level 7
instance on the International Nuclear Event Scale.

5. CONTD In Northern
Ukraine
10 miles away
from Belarus
80 miles North
of Kiev

6. CONTD

7. CONTD
Located 11 miles north of the city of Chernobyl
Plant consisted of 4 reactors
Produced 10% of Ukraine’s electricity
Construction began in the 1970’s
Reactor #4 was completed in 1983
At the time of the accident, reactors #5 and #6 were
in progress.

8. Cause of Chernobyl

9. Flawed operating explanation
Having a mistake or weakness
Ignorant of safety requirement
Lack of experience and training
Insufficient communication
Overconfident : only normal electrical
test
Choosing cheapness over safety

10. Second factor is the operators were not
informed about problems with the
reactor.
The designers knew that the reactor was
dangerous in some conditions but
intentionally concealed this information.
The Chernobyl accident in 1986 was the
result of a flawed reactor design that
was operated with inadequately trained
personnel and without proper regard for
safety
Apart from that the two official
explanations, the causes of the accident
is say to be cause by the poor design of
the plant.

11. Poor Design of Plant
Partial containment was bypassed
and went out on the top of reactor
core.
Hot fuel and graphite were exposed
to air
Cesium and radioactive Iodine

12. Sequence of events
Excessive insertion of control rods
Excessive removal of control rods even more
than the operating levels
Commencement of the test at low levels of
power generation
Excessive water flow rate used
Experiment started
Rise in temperature

13. CONTD
SCRAM started
Displacement of coolant due to control rods
Excessive temperature
Fracture of fuel rods
Control rods stuck
Reactor thermal output 30 GW (10 times
normal)

14. CONTD
Sudden increase in steam pressure
Bursting of cooling water pipes
Reactor Lid blown off
Explosion of either hydrogen or the
graphite

15. Day of disaster
25 April 1986
01:00 The preparation for the test
13:47 Lowering of the reactor power halted at 1,600
MWt
14:00 The ECCS was isolated
23:10 The power reduction resumed

16. 26 April 1986
24:00 Operation shift change
24:28 Power level is now 500 MWt and kept
decreasing to 30 MWt
24:40 The operator withdrew some control rods
01:00 Power had risen to 200 MWt
01:03 Connecting the fourth main cooling pump to
the left loop of the system 200 MWt
01:07 Connecting the fourth main cooling pump to
the right of the loop system - this was a violation of
NOP

17. 26 April 1986 (cont.)
01:19 Increased feed water flow to the steam
drums and removed more control rods -violation
of NOP
01:23 The test was started
01:23:10 Automatic rods withdrawn from the core
01:23:21 Two groups of automated control rods
were back to the core.

18. 26 April 1986 (cont.)
01:23:30 Power kept increasing
01:23:40 Emergency button pushed
01:23:44 Power is at 300000 MWth
01:23:48 1st thermal explosion
01:23:55 2nd explosion

20. (a) International Spread of Radioactivity
The explosion at Chernobyl acted like a
volcano, blowing radioactive particles far
into the sky.
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.

21. (b) Health of People
According to Ukrainian health ministry
officials, 125,000 people have died as a
result of the accident, and more deaths are
expected.
Two people died in the initial steam explosion,
but most deaths from the accident were attributed
to radiation.
Over 300,000 people were moved because of
the accident.
An increase of thyroid cancer has been
diagnosed among children in areas of
Belarus, Ukraine and Russia.
Some believe the stress of the accident has
been worse on people than the radiation.

22. (c) Delayed Health Effects
One of the most delayed effects of the
radiation is the induction of cancer.
For example: Solid cancers among Russian
liquidators whom exposed to more than 150
mSv.
The people in the area of contamination have
suffered a paralyzing fatalism.
Man and young boy
operated for thyroid
cancer after Chernobyl
nuclear accident.

23. The Children of Belarus
Children were much more affected by Chernobyl and
the radiation, due to their weaker immune systems.
1991-1992--sickness rate among children almost
tripled
Threat to gene pool—fewer children being born.
The following problems have increased in Belarusian
children:
heart and circulatory diseases, malignant tumors,
and disorders of the nervous system, sensory
organs, of the bone, muscle and connective tissue
system.

24. Children Contd
It is estimated that 1 out of every 4 infants in Belarus
will develop thyroid abnormalities.
The normal rate of thyroid cancer would be only one
in 1 million.
Normally, this is a rare disease, with only 1 case per
year being reported in Belarus before the Chernobyl
accident.
Thyroid cancer can take 10-30 years to show it’s
effects.

25. Children Contd
Normally, this is a rare disease, with
only 1 case per year being reported in
Belarus before the Chernobyl accident.
Thyroid cancer can take 10-30 years to
show it’s effects.
There has been a 2,400% increase in
the rates of thyroid cancer in Belarus
since 1986.

26. The topic of the children of Chernobyl is most shocking and awful.
The increase in leukemia is even worse where there are dozens of
cases of leukemia among the children.
An increase of thyroid cancer has been diagnosed among children in
areas of Belarus, Ukraine and Russia.
These children have to take painful procedures every day to
postpone the fatal moment.
By year 2000, about 4000 cases of thyroid cancer had been
diagnosed in exposed children.
Mutation in newly born children

27. Flora and fauna
(i)Flora
After the disaster, four square kilometres 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 grow huge pine cones, pine needles of the
needle-like leaves 10 times heavier than normal.
 Some fruits and vegetables also affect which causes the
oddly shaped of potato, tomato and so on.

28. Flora and
fauna
(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.
Figure above: These animals suffering
from a serious effect of mutation
Figure above: A cow that
experiencing mutations. This
co having a cleft lip.

29. Economically
In the 1986 to 1989 industrial and agricultural losses and
insurance payments total about US$36 Billion spent during
this period
The total costs including cleanup, resettlement, and
compensation to victims has been estimated to be roughly
US$200 Billion.
The accident, about US$400 Million was spent on
improvements to the remaining reactors at Chernobyl,
considerably enhancing their safety.

30. CONTD
Between 300,000 and 600,000 people were
brought in to clean-up.
Belarus lost 1/5 of its farming lands(700
million dollars a year loss.)
350 industries were lost due to the disaster.

31. Some Picture of the Disaster