P2 Topic 6 - Using Radioactive Materials

Question 1

Define half-life.

Answer 1

The half-life of a radioactive isotope is the time taken for half of the nuclei to decay.

Question 2

Name a use of alpha radiation.

Answer 2

Household fire alarms - weak source of alpha radiation in between two electrodes. Source causes ionisation and current flows. Smoke absorbs the radiation so current stops, alarm sounds.

Question 3

Name some uses of gamma radiation?

Answer 3

Sterilisation of food and equipment
Tracers
Thickness gauges
Treating cancer

Question 4

Where is each type of radiation more dangerous to the human body?

Answer 4

Alpha - inside

Beta and gamma - outside

Question 5

How is nuclear waste disposed of properly?

Answer 5

Nuclear waste usually can’t be recycled so it has to be disposed of differently. It also has a very long half-life and therefore takes years for it to become non-radioactive.

Most nuclear power stations get rid of waste through vitrification. The waste is melted down and mixed with other materials to make a type of glass, the liquid glass is poured into steel canisters and buried deep underground.

Another method involves packing the waste in thick metal containers and then burying them in deep holes filled with concrete.

Question 6

Where does background radiation come from?

Answer 6

51% radon gas
14% rocks and building material
12% medical x-Rays
12% food
10% cosmic rays
1% nuclear industry

Question 7

Name some advantages and disadvantages of nuclear power.

Answer 7

Advantages:
Nuclear power is actually quite a safe method of producing electricity
Nuclear power is also very reliable and reduces the need for fossil fuels which are running out
Fossil fuels release CO2 which is a greenhouse gas, as well as sulphur dioxide; nuclear power doesn’t release any of these gases
Huge amounts of energy are produced from relatively small amounts of nuclear material
Nuclear fuel is cheap and readily available

Disadvantages:
Public perception is generally quite negative towards nuclear power
There is the dangers that nuclear waste leaks into lakes and rivers
Power plants also have the danger of leaking, like Chernobyl
Finally, the overall cost of nuclear power is high due to the initial cost of the power plant and the final decommissioning, which can take decades