P2.5 and P2.6 Radiation Flashcards
What must always stay the same in an element?
The number of protons and electrons.
What does the number of protons in a nucleus determine?
What element it is.
What is an ion?
An atom with a charge that has lost or gained an electron.
What is an isotope?
A version of an element with more neutrons than it normally has.
What is ionising radiation?
Radiation that has enough power to make atoms lose electrons and become ions.
What are the three types of radiation?
Alpha, Beta and Gamma
What happens when an atom decays?
It emits alpha, beta and gamma radiation and becomes a smaller nucleus that is stable.
What os the penetration order for different types of radiation?
Gamma, beta, alpha.
What is the ionising order for radiation?
Alpha, beta, gamma.
How can you stop the three types of radiation?
Alpha: Paper or skin
Beta: aluminium
Gamma: Lead
What is nuclear fission?
A uranium 235 atom is split by adding another neutron. This then splits into two daughter nuclei and three more neutrons are released, as well as kinetic and thermal energy.
What are daughter nuclei?
The two nuclei produced during fission.
What are control rods in a nuclear reactors?
They absorb some neutrons
What are fuel rods?
Rods in a nuclear reactor that contain the Uranium235 for the reactions.
What is a moderator?
A material in the core that slows down the fast moving neutrons so that they are more likely to react with another Uranium atom.
How is electricity generated in a nuclear reactor?
The thermal energy is used to heat up water which heats up other water to spin a turbine which produces electricity. The steam is then cooled and the heated water cooled as well.
What is radioactive waste made of?
Daughter nuclei and radioactive isotopes formed in the reaction.
What is nuclear fusion?
When small nuclei combine to create a bigger one.
Where is fusion most commonly found?
In stars.
What elements often combine in fusion to form what?
Hydrogen to form helium - Often Hydrogen2 and Hydrogen3 to make helium and an extra neutron.
What is a common effect of too much radiation exposure?
Cancer.
What can occur in cells as a result of exposure to radiation?
Mutations.
What are the three stages of nuclear waste?
High level waste (HLW)
Intermediate level waste (ILW)
Low level waste (LLW)
For how long does radioactive waste stay at each of the levels?
HLW- 50 years
ILW- >10000 years
LLW- > 10000 years
What is the half-life of an element?
The time it takes for half the nuclei in a sample of it to decay.
What can happen to an element after decaying?
It may become stable.
How do you measure radioactivity?
With a Geiger-Müller tube.
What is background radiation?
Low levels of radiation found naturally.
What is a large contributor to background radiation?
Radon gas.
What are some of the uses of radiation?
Diagnosis of Cancer Treatment of Cancer Irradiating food Sterilising equipment Smoke alarms Tracers in the environment Checking material thicknesses.
