Learning Objective:•To review the key areas inpreparation for the P6 Exam. Revision for P6: Radioactive Materials
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 Types of RadiationAlpha• Very ionising• Not very penetrating• Absorbed by paper or dead skin cells• Stopped by only a few centimetres of airBeta• Slightly ionising• Absorbed by aluminium or half a metre of airGamma• Not very ionising• Very penetrating• Absorbed by lead or thick concrete
Efficiency• Efficiency, as a percentage, is worked out by: Useful energy out x100 Total energy in• The more efficient the object is the less energy is wasted or dissipated in an wasteful way• Be able to interpret energy flow diagrams
Background Radiation The dose of radiation is measured in sieverts Sv, or millisieverts mSv.
Contamination IrradiationThis is when the source This is when a sourceis inside the body, or on outside the body affectsyour skin and will affect you – but only when youyou all of the time. are near it.
Damaged – but Radiation repairs itself passes straight through What happens when radiation hits a cell?If it hits a sex It is killed cell it could cause a mutation by The DNA is damaged and changing a the cell develops out of gene control – a cancer has begun
Energy Resources Primary Energy Secondary Energy Source: Source:• A source of energy • A source of energy not made from any that can be distributed other sort of energy easily but has been source manufactured using a• e.g. fossil fuels and primary energy uranium source • e.g. electricity
Renewable: Non-Renewable:Will not run out Fossil Fuels – will rune.g. wind, solar, tides… out; release waste including carbon dioxide; e.g. coal, oil, gas Nuclear Fuels – There are large amounts but not infinite, they release radioactive waste which has to be handled carefully; e.g. Uranium
Fossil Fuel Power StationBe able to label a diagram like this
Nuclear Power StationKnow the differences between these 2 diagrams
Chain ReactionUncontrolled – causes anuclear bomb Controlled – used in a power station
Half Life The half life of a radioactive substance is the amount of time it takes for the activity (amount ofradiation that is given out) to fall to half the previous value.
3 Types of WasteLow Level• e.g. protective clothing and medical equipment• Packed in drums and put in a special landfill siteIntermediate Level• Less dangerous that high level wasteHigh 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
Health and Radioactive MaterialsSome questions will expect you tounderstand and / or discuss:•ALARA•Risks and Benefit•Precautionary Principle•Perceived risk and Actual risk