Topic 10: Ionising Radiation Flashcards
What is ionising radiation?
It is a naturally occurring phenomenon that is widely used
Ionising radiation can cause pollution. Where can radioactive waste result from?
Past nuclear weapons testing
Nuclear waste disposal
Nuclear power plant accidents
Transport,storage and processing of radioactive materials
5 uses of ionising radiation and nuclear power
Industry
Healthcare
Agriculture
Scientific research
Nuclear fission and fusion
Uses of ionising radiation in industry
Measure thickness of rolled metals/paper
Testing aircraft jet engine turbines
Strengthening polymers
In oil and gas exploration to test rock porosity
How is ionising radiation used in healthcare?
Sterilising surgical equipment
Cancer treatment
X-ray photography and CT scans
How is ionising radiation used in agriculture?
Pest control-stored food sterilisation
To sterilise male insects in pest control
Produce mutations in crop breeding programmes
How is ionising radiation used in scientific research?
Radio-labelled tracers to track the movement of materials within organisms or the environment
Uses of ionising radiation in nuclear fission and fusion
Nuclear weapons
500 nuclear test explosions took place up until 1980
Nuclear electricity-generated by nuclear reactors
Ship propulsion- high energy density nuclear fuel. Don’t need to be refuelled often so useful for submarines
What must be done when deciding to use ionising radiaiton?
A risk benefit analysis
Natural sources of radiation
Cosmic radiation from the sun
Gamma rays from the lithosphere
Internal sources in the body
Radon from the ground
Human activities that are sources of radiation
Medical exposure
Small amounts= occupational exposure, weapons fallout,consumer products, industrial effluent discharge
Cosmic radiation
Natural processes in the sum release large amounts of charged sub-atomic particles
When they reach earths surface they are absorbed which releases hight energy electromagnetic radiation e.g. gamma rays
How can you medically be exposed to ionising radiation?
X rays photography or radiography 9injected with radio-opaque drugs)
High does es or radiation to kill cancerous tissues
Uses of radio-labelled substances to track passages and assess any blockages
Examples of industries where there is more chance of being exposed to radiation
Nuclear facilities, mining,radiologists, dental technicians, research scientists,aircraft flight crews
Consumer products that are sources of radiaiton
Smoke detectors/some camping gas mantles contain radionucleids
Small amounts in ceramic/granite worktops
Fertilisers
What is the exposure to radiation that cant be avoided?
Background radiation
E.g. sun,rocks,food
What affects the impact of ionising radiation?
The properties of the different types of radiaiton
E..g ionising radiaiton with poor penetrating power can be more easily absorbed
RBE
Relative biological effectiveness
Measure of the comparitive effects of different types of ionising radiation on living tissues
More damaging forms of radiation have higher RBEs
Properties of alpha radiation
Easily absorbed
Travels short distances
RBE: 20
Health risks of alpha radiation
Absorbed by clothing/dead skin, so alpha emitters outside the body are usually safe
Ingested emitters are dangerous- cause more concentrated damage
Properties of beta radiation
Absorbed moderately easily
Travel a medium distance
RBE:1
Health risks of Beta radiation
They are moderately dangerous
Sources near the body still pose a risk
Properties for gamma rays
Not easily absorbed
Travel long distances
RBE:1
Health risks of gamma radiaiton
Lower danger
Longer distances of travel mean distant sources are still a risk
Properties of neutrons
Absorbed moderately easily
Travel medium distances
RBE: 2-10
Health risks of neutrons
Very dangerous
Pose a risk even after they have been absorbed
Atoms can be changes when bombardeó with neutrons
Half life
The length of time it takes for the original isotope to decay by half
Danger of isotopes with short half-lives
They release radiation quickly so are dangerous, but not for long
Short term precautions may be sufficient to protect workers & public
Dangers of isotopes with long half-lives
Danger for a long time
Emit small amounts over long period, so danger might be low
What isotopes are particularly concerning?
If they have half-lives of several decades
Rate of release of radiation is high
People can be exposed for most/all their lives
Short term protection ensures are inadequate
Effects of ionising radiation on living tissue
When it is absorbed by living tissues, free radicals are produced which have unpaired electrons and can cause biologically damaging reactions
Impacts of ionising radiation on living tissues other than free radicals/because of free radicals
Damage to cell nuclei- causes changes to DNA
Damage to other parts of the cell- organelles dont function properly
Somatic affects,gonads,chronic,acute
What is exposure?
Involves the absorption of ionising radiation
A person must be close enough to a source of radiation
Contamination
Refers to physically carrying radioactive materials which may cause exposure
Principles of controlling ionising radiation
ALARA
BATNEEC
Strategies to reduce exposure
Closed sources
Materials to absorb radiation
Protective clothing
Distance from the source
Reducing period of exposure
Decontamination
Good waste management
How can workers be monitored for exposeure to radiation?
Personal dosemeters- give readings of current exposure
Photographic film badges measure long term exposure
Air monitors
What other monitoring methods can be used for exposure to radiaiton?
Critical pathway analysis
Critical group monitoring
Environmental monitoring
