Radioactive pollution, Summaries of Environmental Science

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RADIOACTIVTY AND ITS APPLICATIONS

Dr Manjunatha S

College of Computer and Information Sciences

Majmaah University

KSA

Presentation outlines

• (^) Introduction to radioactivity
• (^) Sources of radionuclides
• (^) Background radiation
• (^) Applications of radioactivity
• (^) Conclusion

Japanese Fukushima nuclear disaster (2011 ),

• (^) Fukushima Daichi, March 11, 2011 An 8.9 magnitude earthquake and subsequent tsunami overwhelmed the cooling systems of an aging reactor along Japan's northeast coastline. The accident triggered explosions at several reactors at the complex, forcing a widespread evacuation in the area around the plant.

August 10. 1985, Russia, the Echo II class submarine suffered an explosion, sending a radioactive cloud of gas into the air. Ten sailors were killed in the incident and 49 people were observed to have radiation injuries.

• (^) One of the worst nuclear accidents till date.
• (^) The accident killed 30 people directly and damaged approximately $7 billion of property.
• (^) A study published in 2005 estimates that there will eventually be up to 4,000 additional cancer deaths related to the accident among those exposed to significant radiation levels.
• (^) Radioactive fallout from the accident was concentrated in areas of Belarus, Ukraine and Russia. Approximately 350,000 people were forcibly resettled away from these areas soon after the accident.

• (^) Chernobyl, April 26, 1986 The Chernobyl disaster is considered to be the worst nuclear power plant disaster in history. On the morning of April 26, 1986, reactor number four at the Chernobyl plant exploded. More explosions ensued, and the fires that resulted sent radioactive fallout into the atmosphere. Four hundred times more fallout was released than had been by the atomic bombing of Hiroshima.

• (^) On August 6, 1945, the uranium-type nuclear weapon, code named "Little Boy" was detonated over Hiroshima with an energy of about 15 kilotons of TNT
• (^) Destroying nearly 50,000 buildings and killing approximately 70,000 people.
• (^) On August 9, a plutonium-type nuclear weapon code named "Fat Man" was used against the Japanese city of Nagasaki with the explosion equivalent to about 20 kilotons of TNT.
• (^) Approximately 35,000 people killed.

What is radioactivity?

Nuclear decay or radioactivity , is the process by

which a nucleus of an unstable atom loses energy

by emitting ionizing radiation.

A material that spontaneously emits this kind of

radiation which includes the emission of alpha

particles, beta particles, gamma rays and

conversion electrons

Why are elements radioactive?

Unstable nucleus:

• (^) Has excess energy.
• (^) Wants to go to “ground

state.”

• (^) Becomes stable by emitting

ionizing radiation.

Alpha Particles (2n, 2p) Beta Particles (e- or +) Photons (hv) (x or gamma rays) Paper Concrete

Radiation Types

The electromagnetic spectrum

Figure courtesy of NASA/JPL-Caltech

Half life and mean life

Half-life is the time required for half of the atoms

of a radioactive material to decay to another

nuclear form.

Mean life is average of all half lives