•Nuclear Fission•Nuclear Fusion•Induced Nuclear Reaction•Chain Reaction•CANDU Reactors

By Jenny Lee

• NUCLEAR FISSION is the splitting of a more massive nucleus into two less massive nuclei, subatomic particles, and energy.

• Heavy nuclei tend to be unstable, and to increase stability, they split into atoms with lighter nuclei. (Fission)

Fission is accompanied by a very large release of energy.

Fission produces up to 5 neutrons, but 3 is common.

※U-235 absorbs the

neutron and becomes

highly unstable. Then it

produces 3 neutrons and

continues the process.

• CHAIN REACTION is an ongoing process in which one reaction initiates the next reaction. – A nucleus will split an atom, and the atom will produce other

neutrons which will continue the process.

• It can be controlled by materials that absorb neutrons.

※ U-235 absorbs the nucleus and produces two other neutrons. This process continues, and leads to chain reaction.

http://www.youtube.com/watch?v=ekx6gz_s5VM

1. What is the ongoing process in which one reaction initiates the next reaction?

a. Continued Reaction

b. Cause and Effect Reaction

c. Chain Reaction

2. Why does nuclear fission occur?

a. To increase stability

b. To decrease stability

3. Fission is accompanied by a very large release of _______.

a. Gamma Rays

b. Energy

c. Alpha particles

1. C) Chain Reaction

2. A) To increase stability

3. B) Energy

•NUCLEAR REACTIONS are those that involve a change in an atom’s nucleus. •Nuclear Reaction is a process in which an atom’s nucleus changes by gaining or releasing particles or energy.•A nuclear reaction can release all three types of subatomic particles, including gamma rays.•Small change in mass = large change in energy.

•INDUCED (FORCED) NUCLEAR REACTION is when a nuclear reaction is caused by bombarding a nucleus with alpha, beta, or gamma rays.

※ Example of an induced nuclear reaction equation

• CANDU Reactors are Canadian nuclear reactors.

• CANDU Reactor stands for: CANadian Deuterium Uranium reactor.

Deterium is an isotope of Hydrogen-1 that is twice as heavy. It has a proton and a neutron.

• NUCLEAR FUSION is the process in which two low mass nuclei join together to make a massive nucleus.

• Fusion occurs at the core of sun and other stars, where there is sufficient pressure and high enough temperature to force isotopes of Hydrogen to collide with great force.

In the sun, fusion reaction occurs between hydrogen-2 and hydrogen-3. When these two combine, they produce a huge amount of energy.

※Fusion nuclear equation

http://www.youtube.com/watch?v=3rn339v_Q-w

1. Where is one location at which nuclear fusion occurs?

a. Core of Sun

b. Core of Moon

c. Core of Earth

2. What does CANDU stand for?

a. Canadian Diterium Ununtrium

b. Canadian Dioxide Uranium

c. Canadian Deuterium Uranium

3. What is produced when hydrogen-2 and hydrogen-3 are combined?

a. Smoke

b. Energy

c. Gamma Rays

1. A) Core of Sun

2. C) Canadian Deuterium Uranium

3. B) Energy