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Nuclear Energy. Key points:. Nuclear energy is harnessed from changes occurring in unstable atomic nuclei. Nuclear energy originates from the splitting of uranium atoms in a process called fission.
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Key points: • Nuclear energy is harnessed from changes occurring in unstable atomic nuclei. • Nuclear energy originates from the splitting of uranium atoms in a process called fission. • Natural radioactivity is the spontaneous disintegration of unstable nuclei, emitting large amounts of energy in the form of ionizing radiation.
The different kinds of ionizing radiation differ in their penetrating and ionizing powers. - Alpha -Beta - Gamma • A sheet of paper can stop alpha rays; on the other hand, it would take a thin sheet of aluminum or almost any other metal to stop beta rays. Gamma rays, however, can be stopped only by thick lead.
Half-life is the time required for one-half of the number of atoms originally present in a radioactive sample to decay. • Ionizing radiation exerts both somatic and genetic effects. Somatic effects affect the victim during his/her lifetime.
Somatic effects includes : - burns - cancer - damages to body tissues, particularly the spleen, bone marrow, lymph nodes - blood-forming tissue • Genetic effects affect the victims through his/her offspring by causing genetic mutation.
Radiation effects are believed to be cumulative. • Ionizing radiation can be both kill and cure. It is used in medical diagnosis and treatment. • Artificial radioactivity is artificially induced nuclear change where the product nucleus is radioactive.
Worldwide Nuclear Power Reactors • There are 440 nuclear power reactors in 31 countries. • 30 more are under construction. • They account for 16% of the world’s electricity. • They produce a total of 351 gigawatts (billion watts) of electricity.
Nuclear Electricity Production by Countries and Regions in Gigawatts (World Total 350 Gigawatts) and percent of electricity
Nuclear fission involves the splitting of a heavy nucleus into two smaller nuclei with a mass ratio of 1:1 to 1:1.5. This happens when the nucleus is bombarded with high-energy particles like neutrons, deuterons, and protons.
Fission means “to divide” • Remember that fission has 2 s’s, therefore it splits into TWO parts
A chain reaction is an ongoing series of fission reactions. Billions of reactions occur each second in a chain reaction.
On earth, nuclear fission reactions take place in nuclear reactors, which use controlled chain reactions to generate electricity.
Nuclear fission when controlled and self-sustained can be made to generate energy that can be harnessed for peaceful uses. This happens in nuclear reactor. • Uncontrolled chain reactions take place during the explosion of an atomic bomb.
The products of nuclear fission reactions are radioactive, but the energy released from these reactions is less harmful to the environment than the use of fossil fuels. • A nuclear power plant is only about 30% efficient. Most of the energy is lost to the environment as waste heat.
Unresolved problems associated with nuclear power plant operation include the following: • Thermal pollution of bodies of water where cooling water is discharged • Processing of spent fuels has associated occupational hazards • Long-lived radioisotopes released during nuclear accident are environmental and health hazards
d. The safe disposal and management of large amounts of nuclear waste produced e. The possibility of human error resulting in nuclear accident • Cleaning up during a nuclear accident is very costly
LAKE AGKO • L
LAKE AGKO • L
LAKE AGKO • L
