Nuclear Catastrophes
International Nuclear Event Scale
·
Introduced in 1990 by IAEA
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Enables prompt communication of safety
significance in case of nuclear accidents
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Logarithmic
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There are 7 levels: 3 incident levels and 4
accident levels
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Level 7 – Major accident: Chernobyl, 1986
·
Level 6 – Kyshtym disaster (Mayak, Soviet
Union), 1957
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Level 5 – Three Mile Island US, 1979; Windscale
Fire (UK), 1957
Chernobyl Disaster
Three Mile Island Disaster
2011 Japan Nuclear Disaster
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At the three
reactor units at the Fukushima Daiichi nuclear power station
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Located in the town of Okuma in the Futaba
District of Fukushima Prefecture, Japan. Combined capacity of 4.7 GW.
·
What caused it?
o
The earthquake caused a power failure
o
The subsequent tsunami knocked out the
generators that produced the power
o
Lack of power in turn caused the cooling systems
of the reactors to fail
o
This led to a partial meltdown in the three
reactors
·
Background
o
Fukushima 1 reactor went critical in 1971
o
All the three are Boiling Water Reactors (BWR)
and use demineralised water for cooling nuclear fuel
·
Methods that can be adopted to avoid a meltdown
o
Pump sea water to reduce the heat
o
Boric acid is an excellent neutron absorber.
Using it would reduce the chances of nuclear reactions restarting even if the
fuel is found loose inside the reactor core.
o
Nuclear Safety
·
The disaster has re-ignited the debate on the
safety of nuclear power
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AERB should be made an independent regulator
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Earthquakes
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Ring of fire in the pacific ocean
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Largest Earthquakes by Magnitude
o
Valdivia, Chile,
1960: 9.5
o
Prince Sound Willaim, Alaska, 1964: 9.2
o
Sumatra, Indonesia,
2004: 9.1
o
Kamchatka, USSR,
1952: 9
o
Sendai, Japan,
2011: 9
Tsunami
·
Intensity measured by the Soloviev-Imamura
tsunami intensity scale.
·
Major Tsunamis
o
2011: Japan
o
2004: Indian Ocean
o
1908: Messina, Italy
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