Nuclear fission is the splitting of a heavy nucleus into lighter nuclei and is accompanied by a large release of energy. It can occur through a chain reaction where one fission reaction causes additional reactions. Nuclear fusion is the process where two light nuclei fuse to form a heavier nucleus and occurs at extremely high temperatures in stars. CANDU reactors are Canadian reactors that use deuterium and uranium for induced nuclear reactions.

1. •Nuclear Fission
•Nuclear Fusion
•Induced Nuclear Reaction
•Chain Reaction
•CANDU Reactors
By Jenny Lee

2. • 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.

3. • 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.

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

5. 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

6. 1. C) Chain Reaction
2. A) To increase stability
3. B) Energy

7. •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

8. • 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.

9. • 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

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

11. 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

12. 1. A) Core of Sun
2. C) Canadian Deuterium Uranium
3. B) Energy