Nuclear Energy

11.3 Notes

Atomic Structure

1.Atomic Structurea. The structure of an atom consists

of protons and neutrons in the nucleus and electrons on the energy levels surrounding the nucleus.

Atomic Structure

i. The electrons in the outermost energy level of the atom, the valence electrons, are involved in forming chemical bonds.

ii.While the nucleus is not involved in forming bonds, it can undergo changes that will release a great amount of energy.

Nuclear Fission

2. Nuclear Fissiona.Nuclear fission is the splitting of the

nucleus of an atom into two or more smaller nuclei. i.This releases a large amount of heat

energy that can be used to generate electricity.

Nuclear Fission

The Process of Nuclear Fission

b. The process of nuclear fission involves a rare isotope of uranium called uranium-235.i. The uranium-235 is then processed into

fuel pellets, which are then placed into rods to make fuel rods.

The Process of Nuclear Fission

ii. When the fuel rods are bombarded with neutrons, a neutron strikes a uranium-235 atom, which causes the nucleus to split and release a large amount of energy and more neutrons.

Fuel Rods

The Process of Nuclear Fission

iii. The release of these neutrons causes a chain reaction, because these neutrons are also striking the nucleus of neighboring U-235 atoms.

iv. This chain reaction of splitting atoms generates a large amount of heat, which if not cooled can cause a “melt down”.

Nuclear Chain Reaction

The Process of Nuclear Fission

v. Water is pumped in to cool the rods, and during this process, some of the water turns to steam, which is used to turn turbines and generate electricity.1. The water is then reused and pumped

back into the fuel rod system.

The Process

The Process of Nuclear Fission

vi. A nuclear reactor is used to control the flow of neutrons and the speed of the reaction, or nuclear fission, taking place.

vii.The product of nuclear fission is depleted and highly radioactive nuclear waste.

The Process of Nuclear Fission

1. Some of this waste may be stored on site or in disposal facilities in the Unites States.

2. The department of energy is creating permanent disposal methods for this nuclear waste.

Nuclear Waste

Nuclear Fusion

3. Nuclear Fusiona.Nuclear fusion is the combination of smaller

nuclei atoms to form a larger nucleus.i.This energy is the type of energy produced by

the sun. In the sun, energy is released when hydrogen nuclei combine and form helium nuclei. These reactions can take place only at temperatures of more than 15 million degrees Celsius.

Nuclear Fusion

Deuterium and Tritium are isotopes of Hydrogen. They undergo fusion to produce helium, heat, and energy.

Nuclear Fusion

b.While this energy is around us all of the time, scientists are still unable to duplicate this process.

c. If a large nuclear fusion reactor would be built, a source of fuel could be hydrogen atoms from ocean water.i. This would create an almost limitless fuel source

and the waste from fusion is much less dangerous than that of fission.