P2e: Nuclear radiations Flashcards
Beneficial uses of nuclear radiation (1 + 2 + 3)
alpha - smoke detectors
beta - some tracers; paper thickness gauges
gamma - medical uses - treating cancer(gamma knife), medical tracers; sterilising equipment
How are alpha particles used in smoke alarms? (5)
alpha particles not very penetrative, but very ionising
smoke alarms contain weak source of alpha radiation
alpha radiation ionises air inside alarm, creates small electric current
when smoke enters alarm, current drops, setting off alarm
if no smoke, no change in current, alarm quiet
How are beta particles used in paper mills? (5)
more penetrative, less ionising than alpha; less penetrative, more ionising than gamma
can travel through several sheets of paper
in paper mill, sheets of paper pass between beta source and detector which counts the beta particles
some beta particles don’t pass through; the more thick the paper is, the fewer that get through, so less counts recorded by counter
if counts fall too low, shows paper is too thick, rollers squeeze together
Medical uses of gamma rays (4)
gamma rays very penetrative, not very ionising
gamma knife - movable source of gamma rays, fired into body and focused on tumour; moved around to reduce exposure on healthy
tissue but provide high enough dose to kill tumour cells
sterilising equipment - gamma rays kill bacteria on instruments, making them safe for future operations
medical tracers - weak gamma source swallowed / injected; gamma rays travel around body, camera used to monitor flow to look for
blockages/leaks
Describe the relative penetrating power of alpha, beta and gamma
Alpha - stopped by skin or paper
Beta - stopped by a few mm of aluminium
Gamma - stopped by a few cm of lead
Most ionising to least ionising
alpha, beta, gamma
What does ionising radiation mean?
the radiation causes electrons to be added or removed from atoms, forming charged ions
How can ionisation damage human cells? (5)
when DNA in cell is ionised, it changes interactions in cell
ionised parts repel/attract each other, so cell does not behave as it should
ionisation also initiates chemical reactions that would not normally occur
-such reactions may disrupt the normal behaviour of molecules inside the body(e.g. cause strands of DNA to breka or change)
severe damage to DNA may lead to cancer and cell death
Describe uranium
a non-renewable resource
Describe plutonium(2)
a waste product from nuclear reactors
can be used to make nuclear bombs.
Describe some ways of disposing of radioactive waste(3)
low level waste buried in landfill sites
high level waste encased in glass and buried underground
high level waste can be reprocessed
Advantages of nuclear power (3)
concentrated source of energy - large amounts of electricity can be generated for each kg of fuel used compared to fossil fuels
the fuel is readily available and, unlike fossil fuels, won’t run out for thousands of years
no burning so no polluting gases such as CO2 are produced, so no contribution to global warming or acid rain
Disadvantages of nuclear power (7)
high cost of building and decommissioning the plant
nuclear fuel must be processed before use
nuclear reactors have very slow start up time - takes a long time to increase or decrease amount of electricity they generate
radioactive waste very dangerous to living things
can be very expensive to process radioactive waste
stored waste are terrorist target
risk of accident that could release radioactive waste into environment
Problems of dealing with radioactive waste (5)
remains radioactive for a long time so long term solutions are required
it must be placed in a material resistant or thick enough, to stop gamma penetrating
must be kept out of groundwater, no possibility of it contaminating water supply
must monitor levels of radioactivity for long time as acceptable radioactivity level may change over time
terrorist risk
