Chernobyl disaster and what are the lessons we have to learn especially India which having 21 Nuclear Centers or Plants Reference Video Link is given below https://www.youtube.com/watch?v=R9JSGU8MRb0

1. CHERNOBYL
DISASTER
V.Lokeswar Reddy , CE Dept, CBIT Pdtr,

2. ◦Energy neither created or destroy ,
But……………………………………….

4. INTRODUCTION:
◦ Chernobyl disaster was happened on April 26 1986
◦ The Chernobyl disaster was a nuclear accident that occurred on 26 April 1986
at the No. 4 nuclear reactor in the Chernobyl Nuclear Power Plant, near the city
of Pripyat in the north of the Ukrainian SSR.[1][2] It is considered the worst
nuclear disaster in history and is one of only two nuclear energy disasters rated
at seven—the maximum severity—on the International Nuclear Event Scale,
the other being the 2011 Fukushima Daiichi nuclear disaster in Japan.
◦ 100 times more power radio activity than Hiroshima .

6. ◦ Chernobyl consists of Total 6 reactors , disaster happen due to the false in 4 th
reactors .
◦ USSR believe that the Nuclear power is safest to handle and generate the
electricity almost 4000MW from each reactor.

7. The power plant:
◦ The Chernobyl plant used four Soviet-designed RBMK-1000 nuclear reactors — a
design that's now universally recognized as inherently flawed. RBMK reactors
were of a pressure tube design that used an enriched U-235 uranium dioxide fuel
to heat water, creating steam that drives the reactors' turbines and generates
electricity, according to the World Nuclear Association.
◦ In most nuclear reactors, water is also used as a coolant and to moderate the
reactivity of the nuclear core by removing the excess heat and steam, according
to the World Nuclear Association. But the RBMK-1000 used graphite to
moderate the core's reactivity and to keep a continuous nuclear reaction
occurring in the core. As the nuclear core heated and produced more steam
bubbles, the core became more reactive,

9. Reaction process:
1. As the reaction occurs, the uranium fuel becomes hot
2. The water pumped through the core in pressure tubes removes the
heat from the fuel
3. The water is then boiled into steam
4. The steam turns the turbines
5. The water is then
cooled
6. Then the process repeats

10. What happened :
◦ Operators were planning on testing the electrical systems when they turned off vital
control systems, going against the safety regulations. This caused the reactor to
reach dangerously unstable and low-power levels.
◦ Reactor 4 had been shut down the day before in order to perform the maintenance
checks to safety systems during potential power outages, according to the Nuclear
Energy Agency (NEA).
◦ The excess steam was created by the reduction of the cooling water which
caused steam to build up in the cooling pipes — the positive-void coefficient —
which caused an enormous power surge that the operators could not shut down.
The power fell too low, allowing the concentration of xenon-135 to rise.
◦ -The workers continued the test, and in order to control the rising levels of xenon-
135, the control rods were pulled out.

11. ◦ The explosions occurred at 1:23 a.m.
on April 26, destroying reactor 4 and
initiating a booming fire, according to
NEA. Radioactive debris of fuel and
reactor components rained over the
area while fire spread from the
building housing reactor 4 to adjacent
buildings. Toxic fumes and dust were
carried by the blowing wind, bringing
fission products and the noble gas
inventory with it.

12. Reactor design:

13. ◦ Most of the radiation released
from the failed nuclear reactor
was from fission products
iodine-131, cesium-134, and
cesium-137. Iodine-131 has a
relatively short half-life of eight
days, according to UNSCEAR,
but is rapidly ingested through
the air and tends to localize in
the thyroid gland. Cesium
isotopes have longer half-lives
(cesium-137 has a half-life of 30
years) and are a concern for
years after their release into the
environment.

14. ◦ After few months reactor 4 was covered by
the concrete and steel structure to reduce
the emission of radioactive .

15. Lessons from Chernobyl disaster:
• The accident has shown the importance of strict compliance
with the basic and technical safety principles for nuclear power
plants, of continuous safety analysis of operating nuclear power
plants and of their early upgrading in order to eliminate
deviations, of active study and the introduction of leading world
experience, and of taking thorough account of the human factor.
• The accident has demonstrated the need to establish and
support a high-level national emergency response system in
case of man-made accidents.

16. Thank you …………….
◦ “Utilization must and should be satisfy our needs , but not for luxury “ other wise …………….the
below photograph will repeat again.