Revision for P3: Radioactive Materials

1. Learning Objective: • To review the key areas in preparation for the P3 Exam. Wednesday, 02 April 2014 Revision forP3: Radioactive Materials

2. Nuclear Radiation • Comes from the nucleus • Nucleus contains neutrons and protons • Electrons orbit around the edge Electrons Nucleus Two isotopes of Carbon – both have 6 protons but different numbers of neutrons.

3. 3 Types of Radiation Alpha • Very ionising • Not very penetrating • Absorbed by paper or dead skin cells • Stopped by only a few centimetres of air Beta • Slightly ionising • Absorbed by aluminium or half a metre of air Gamma • Not very ionising • Very penetrating • Absorbed by lead or thick concrete

4. Efficiency • Efficiency, as a percentage, is worked out by: • The more efficient the object is the less energy is wasted or dissipated in an wasteful way • Be able to interpret energy flow diagrams

5. Background Radiation The dose of radiation is measured in sieverts Sv, or millisieverts mSv.

7. Damaged – but repairs itself Radiation passes straight through What happens when radiation hits a cell? If it hits a sex cell it could cause a mutation by changing a gene It is killed The DNA is damaged and the cell develops out of control – a cancer has begun

8. Primary Energy Source: A source of energy not made from any other sort of energy source e.g. fossil fuels and uranium Secondary Energy Source: A source of energy that can be distributed easily but has been manufactured using a primary energy source e.g. electricity Energy Resources

10. Fossil Fuel Power Station Be able to label a diagram like this

11. Nuclear Power Station Know the differences between these 2 diagrams

12. Fission Neutron

13. Chain Reaction Uncontrolled – causes a nuclear bomb Controlled – used in a power station

14. Half Life The half life of a radioactive substance is the amount of time it takes for the activity (amount of radiation that is given out) to fall to half the previous value.

15. 3 Types of Waste Low Level • e.g. protective clothing and medical equipment • Packed in drums and put in a special landfill site Intermediate Level • Less dangerous that high level waste High Level • E.g. spent/old fuel rods • This gets hot as it is so radioactive, it’s kept in a pool of water to absorb the heat

16. Health and Radioactive Materials • Some questions will expect you to understand and / or discuss: • ALARA • Risks and Benefit • Precautionary Principle • Perceived risk and Actual risk