Benefits And Drawbacks Of Using Radioactuve Materials Flashcards
Who and how was radioactivity discovered
Henri becquerel was investigating how uranium emits light after being exposed to the sun. On a cloudy day, he put some uranium into a draw with a photographic plate and when he opened the drawer, the plate had unexpectedly become exposed, he realised that radiation emitted from uranium didn’t need and external energy source. This is radioactivity
How can radiation cause cancer
They ionises celles and change the DNA in its nucleus. This is called a mutation which could cause it to rapidly grow and become cancer.
What safety measures are used when handling and storing radioactive materials
They are kept in lead lined boxes as the radiation is stopped by it. They are also handled with tongs to keep them away from the handler. We also don’t point them at people and in some cases, special suits are worn.
What is HLW and give an example of it
HLW is High level waste and is very radioactive waste material such as waste products in nuclear fission. They can produce large amounts of ionising radiation for over 50 years.
What is ILW and an example
ILW is intermediate level waste and is less radiative than HLW but remains moderately radioactive from 10s of thousands of years. HLW becomes ILW after about 50 years. Another example of ILW is the metal containers that stored the uranium fuel.
What is LLW and example
LLW is low level waste and is slightly radioactive but like ILW it stays like this for tens of thousands of years. It includes clothing and cleaning materials used in power stations.
Why are hospitals a source of LLW
Hospitals are sources of LLW as they use radioactive isotopes in treatment such as radiotherapy for cancer patients.
How is HLW stored
HLW is stored in metal and concrete containers to absorb the radiation. These containers are sealed in glass to make sure no radioactive material escapes. These are put into containers and stored until it becomes ILW
What is ILW stored in
It is stored in steel and concrete containers
How is LLW stored
It is compacted and buried in special landfill sites and can’t be put into normal ones as there is a risk of radioactive material leaking into water or soil.
What is are advantages to nuclear power
It doesn’t create any CO2 so it doesn’t contribute to g tonal warming. It also doesn’t need much fuel so is very efficient
What are disadvantages to nuclear power
It is very expensive to set up the power plant
The production of fuel rods uses lots of energy which may have been sourced from fossil fuels
It is very expensive to store nuclear waste as it can’t be leaked into the environment and needs to be stored for a very long time
If there is a meltdown then radioactive material may be spread over a very large area.
What is nuclear decay and how is it measured
Nuclear materials decay to become more stable. The number of decays per second is measured in becquerels (Bq) 1 Bq is one decay per second.
What is half life
The time it takes for half of a nuclear material to decay. This can be seconds or millions of years. It is the same for however much of an isotope there is.
How is the radioactivity measured
Measured by a Geiger muller tube (GM) which clicks every time ionising radiation is detected
What is the count rate and what is it used for
The count rate is the number of clicks a GM tube makes every second. This can be used to work out the half life of a material from a graph
What is a half life of a material that clicks 600 counts per second at 5 minutes and 300 times at 12 minutes
12-5 = 7 so half life is 7 minutes
What is background radiation
Low level ionising radiation from the environment
What 6 things contribute back ground radiation and what percentage do they contribute
Radon gas 50% Buildings and ground 14% Cosmic rays 10% Medical 14% Nuclear power 0.3% Food and drink 11.5% Other 0.2%
Where does radon come from
Uranium is found in rocks. When this uranium decays, it creates isotopes including radon fas
How are gamma rays used to help detect cancer
A tracer solution containing a source of gamma rays is injected into the body. This builds up in areas of abnormal activity such as where there is cancer. The gamma rays penetrate through the body and are detected by a gamma camera. This shows where there may be cancer
Why can only gamma rays be used to detect cancer
Alpha and beta particles are absorbed by the body so won’t be detected
How can radiotherapy cure cancer
Gamma rays can be aimed towards the cancer and fired in beams, killing the cancer
Uses of radiation (4)
Diagnosing cancer
Treating cancer
Sterilising equipment such as plastic as it kills the microorganisms (they are irradiated)
Irradiating food
Why is some food irradiated
To kill bacteria and organisms on the food. This can slow down its decomposition and make it safer to eat. Foods that are allowed to be irradiated include potatoes, fruit, vegetables, fish and poultry…..
What is a main use of alpha particles and how does it work
Smoke detectors. They contain 2 electrically charged plates, negative and positive and a source of alpha particles (americium-241). The alpha particles ionise the air between the plates which gives out electrons and ions. These are attracted to the oppositely charged plate creating a small circuit. This is always happening unless something absorbs the alpha particles, in which the circuit breaks. When there fire, the smoke absorbs the alpha particles and breaks the circuit. This triggers an alarm.
What is a main use of beta particles and how does it work
When paper is rolled, it needs to be the correct thickness. To do this a beta source is put under the paper and a detector is above it. When the paper is too thin, the detector detects more beta particles so it tells the computer to reduce pressure on the rollers, if it is too thick, the opposite happens.
What is an environmental use of gamma rays and how does it work
Gamma rays can be used to detect leaks in water pipes. A tracer is added to the water which flows through the pipe. A GM tube is moved along the ground above the tube and detects the gamma rays. Where there is a leak, there are more gamma rays and the GM tube detects this.
Why are alpha particles ideal for smoke alarms
Why are beta particles ideal for measuring e thickness of paper
Why are gamma rays ideal for finding leaks in pipes
Alpha particles as they ionise particles fast so lots of electrons are released so the currant stays strong and they can’t penetrate the casing of the alarm so aren’t harmful to anything
Beta particles as the can penetrate enough through paper but at the same time, little enough so not all gets through which can be detected whereas if gamma rays were used, all would get through and if alpha were used, none would get through
Gamma rays as they aren’t as harmful as alpha and beta and can penetrate far so they can be detected through the ground.
