P6 - Radioactive Materials Flashcards
Atom
The smallest part of the element it makes up
What was the 1909 Rutherford-Geiger-Marsden Alpha Scattering Experiment? (2)
An experiment to prove the structure of an atom, during which alpha particles were fired at gold foil
What were the three observations recorder during the 1909 Rutherford-Geiger-Marsden Alpha Scattering Experiment?
- Most alpha particles passed straight through the gold foil undeviated
- A few particles were deflected through small angles
- Even fewer bounced straight back from the foil
What were the three conclusions of the 1909 Rutherford-Geiger-Marsden Alpha Scattering Experiment?
- The atom is mostly empty space since most particles went straight through
- The mass and charge of an atom is concentrated in a small area in he centre of the atom (nucleus)
- The nucleus was positive because the positive alpha particles were repelled
Isotopes
Atoms of the same element with the same number of protons but differing numbers of neutrons
Name the three isotopes of Hydrogen:
Hydrogen = 1 neutron Deuterium = 2 neutron Tritium = 3 neutron
What does ionising radiation do to atoms?
It knocks electrons off and turns atoms into positive ions
Background radiation
Low level ionising radiation that is all around us
What are the 6 main sources of background radiation?
- Gamma rays from the ground and buildings
- Medical Sources
- Radon gas from the ground
- Nuclear power/ weapons testing
- Food and Drink
- Cosmic rays
The amount of radiation emitted by a radioactive source depends on…
The amount of radioactive material present
What are the three types of ionising radiation?
Alpha, Beta and Gamma
What are the properties of alpha radiation? (4) (structure, charge, ionisation, penetration)
- Two protons, two neutrons like a helium nucleus
- 2+ charge
- Highly ionising
- Low penetration
What are the properties of beta radiation? (4) (structure, charge, ionisation, penetration)
- Fast moving election
- 1- Charge
- Medium ionising power
- Medium Penetration
What are the properties of gamma radiation? (3) (structure, ionisation, penetration)
- High frequency electromagnetic wave
- Low ionising power
- High penetration
What materials can be used to absorb each type of ionising radiation? (3)
Alpha particles - Paper
Beta particles - Thin sheet of aluminium
Gamma rays - Thick block of lead/ concrete
How does high intensity radiation affect living cells? (2)
It can kill living cells and cause tissue damage leading to radiation sickness or cause cells to become sterile
How does low intensity radiation affect living cells?
It can affect the genetic makeup of a cells, causing mutations that could lead to cancer
Which type of radiation is dangerous inside the body and why?
Alpha radiation is the most dangerous because it is easily absorbed by cells
Which type of radiation is dangerous outside the body and why?
Beta and Gamma radiation because they can penetrate the body
What is the unit of Radiation absorbed?
A sievert (Sv)
What 4 elements are the most highly susceptible to ionising radiation in the body?
Oxygen, Hydrogen, Nitrogen and Carbon
Radioactive decay
When the radioactivity of of a material decreases over time as the amount of radioactive nuclei decreases
What happens in an atom during beta emission?
A neutron becomes a proton
What does emitting a gamma ray do to an atom?
Release energy only
Half life
The time it takes for half of the nuclei in a radioactive element to decay
What are the four main uses of ionising radiation?
Treating cancer, Sterilising medical instruments, Sterilising food, Detecting tumours
What are radioactive tracers and what type of radiation is used by them and why?
Devices used to detect brain and other tumours; these use beta or gamma radiation so that the skin and tissues can be penetrated
Irradiation
Exposure to radiation
Contamination
When a radioactive material is mixed up with a person or surface
What is a film badge used for?
To measure the level of exposure to radiation someone or something has had
Nuclear fission
When two heavy nuclei are split into two smaller nuclei and energy is released
Nuclear fusion
When two nuclei fuse to form a larger nucleus and energy is released
What two radioactive elements are used to start off nuclear fission reactions?
Uranium and Plutonium
Chain reaction
When the nuclei released from a starting nuclear fission go on to initiate more and more increasing nuclear fissions
What are the three categories of Radioactive waste and give an example of each? (6)
- Low level Waste: contaminated paper/ clothes
- Intermediate level Waste: Chemical sludges, reactor parts
- High level Waste: Spent fuel rods
How is low level radioactive waste disposed of? (3)
Burnt, sealed in containers and buried in landfill
How is intermediate level radioactive waste disposed of? (2)
Shielded, longer half lives are buried deep underground
How is high level radioactive waste disposed of? (3)
Mixed with molten glass, contained in steel drums and stored carefully
Coolant (in terms of nuclear power)
A gas/liquid circulated around a nuclear reactor to absorb heat energy and transfer it to a steam generator
What are nuclear power control rods usually made of?
Boron
What do control rods do in nuclear power and how are they used?
They absorb excess neutrons and are raised or lowered into the reactor to control the fission
Why is nuclear fusion power better than fission power? (3)
- It releases a lot more energy per kg
- It doesn’t release carbon dioxide into the atmosphere
- The reactants (isotopes of hydrogen) are readily available and only needed in small amounts
What is the problem with nuclear fusion?
More energy is consumed producing its ideal conditions than it releases
