Chain reactions and Nuclear Reactors

Question 1

Define Chain Reaction:

Answer 1

Refers to a process in which neutrons released in a fission reaction produce additional fission in at least one further nucleus. This fission produces additional neutrons in which the process is repeated.

Question 2

What are the two types of chain reactions?

Answer 2

Controlled (Nuclear Reactors), and Uncontrolled (Atomic bombs)

Question 3

Process of Nuclear Reactors:

Answer 3

In nuclear reactors, controlled fission reactions occur to produce thermal energy to vaporize and produce steam which in turn gets work done on a turbine which then powers a generator to produce electricity or nuclear power.

Question 4

Features of a nuclear reactor:

Answer 4

-Fuel Rods
-Moderator
-Control Rods
-Coolant
-Shielding

Question 5

Define enrichment:

Answer 5

Enrichment refers to the process in which uranium ore is refined to increase the concentration of uranium 235.

Question 6

Fuel Cylinders:

Answer 6

Are long cylinders that pack/store pellets of enriched uranium for later use.

Question 7

Moderator:

Answer 7

A material between fuel rods. They are placed to slow down fast-moving neutrons for reactions to occur. (Heavy Water H-2 Ideal) Also, they absorb neutrons if there are too much of them, this is to prevent an uncontrolled chain reaction.

Question 8

Control Rods:

Answer 8

Control rods are used to slow down chain reactions if they are going too fast. They are lowered in between fuel cylinders so they can absorb neutrons to slow or stop the process to prevent uncontrolled chain reactions. (are made of materials such as cadmium, silver, boron, carbide, etc).

Question 9

What is shielding?

Answer 9

Steel case that encloses a nuclear reactor that is surrounded by several metres of concrete to prevent any radiation/ radioactive material from escaping.

Question 10

Radioactive Waste Levels:

Answer 10

Low level - (Protective clothing) Buried underground
Intermediate Level - (Parts of reactors) put in steel drums encased in concrete for storage underground.
High-level - (used fuel) fused into glass blocks and stored underground.

Question 11

Nuclear Fusion:

Answer 11

Occurs when two small nuclei join together to form larger nuclei. The reaction releases 1000x the energy per gram than a fission reaction.