Chernobyl
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Nuclear energy o Radiactivity History o Nuclear power o Chernobyl disaster
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Transcript of Chernobyl
Nuclear energy
o Radiactivity History
o Nuclear power
o Chernobyl disaster
Radiactivity History
X rays discovery
Wilhelm Röntgen• 1895: First detection of a
new kind of radiation in vacuum tubes
• 1901: Nobel Prize in
Physics
Radiactivity discovery
Henri Becquerel• 1896: recognition of a new
property in uranium salts
• 1903: Nobel Prize in
Physics
New elements discovering
Maria Sklodowska and Pierre Curie• 1898: isolation of
Polonium and Radium
• 1903: Nobel prize in Phisics
• 1911: Nobel Prize in Chemistry
Types of radioactivityErnest Rutherford• Scattering in a
magnetic or electrical field
• Nobel prize in Physics (1908)
Types of radiactivity
: massive and positive particles (Helium nuclei). They can be stopped by a sheet of paper
: electrons; stopped by an aluminium shielding
: electromagnetic radiation, reduced by a lead barrier
Atomic models
Ernest Rutherford
• 1911: atomic nucleus with protons and neutrons surrounded by an electron cloud
• Radiactivity: nuclear emission of either energy or subatomic particles
Nuclear power
Nuclear fission
Fission
Splitting of the nucleus of an atom into nuclei of lighter atoms, releasing a great amount of energy
Nuclear fission
o 1938: Lise Meitner, Otto
Hahn y Frederic Strassman (Nobel de Física, 1944), who observed fission of uranium-235 using slow neutrons
235 U + 1 n → 141 Ba + 92 Kr + 3 1 n
Nuclear reactorsEnrico Fermi
• 1934: first nuclear reaction
controlled by slow neutrons
• 1938: Nobel Prize in Physics• 1942: first nuclear reactor• 1945: leading “Manhattan
project”
Nuclear weapons
o August, 6th 1945:
Hiroshima
140,000 dead (December,1945)
o August, 9th 1945:
Nagasaki 70,000 dead
(December 1945)
Nuclear power stations
Plant that generates electricity using the heat released in a nuclear fission process
Nuclear power stations
Nuclear power stations in Spain
Radioactive wastes
High levelo Release a great amount
of heat and radiationo usually long half-lifeo Stored in spent fuel
pools or in dry cask storage
Low activityo No release of heato less than 30 years of
half-life
Chernobyl
Chernobyl
o Nuclear power station, 4 reactor, each of 1 Gwatt.
o Located in Ukraine, near the border
o 10 % of the amount of energy
o No vessel
Accident
April, 26th, 1986
o Chain reaction out of control in reactor 4
o Steam explosiono Hidrogen explosion
which tore the top of the building
Burning
o Graphite and hidrogen burning, due to the oxigen
o Extinguished with 5000 t of sand, lead, clay, etc.
Radiactive fallout
o 5,6 Röntgen/s (lethal dose: 500 Röntgen/h)
o 400 times more than the amount spread in Hiroshima
Radiactive fallout
o Debris removed and collected by hand (40 s)
o 3.9 million km2 polluted by 137Cs (34 % of UK, 44 % of Germany)
Firefighters: liquidatori
Sarcophagus
o Large concrete sarcophagus erected in December
o Supported and controlled by European Union
o New save confinement structure will be built in 2011
Pripyat evacuation
o High radiattion levels detected in Sweden, 1100 km from Chernobyl
o Started on December, 27th
Chernobyl today
• 7 million people affected
• 30,000/60,000 dead people due to the accident
Chernobyl today
Pripyat today
Pripyat today
Prypiat today
Prypiat today
Chernobyl today
o 30 km exclusion zone
o Some people have come back
o Prypiat dead city
New sarcophagus
Conclusions
