Nuclear Power Flashcards
what 3 nuclear reactions can be used as a source of energy
radioactive decay
nuclear fission
nuclear fusion
why is nuclear power efficient
is a highly efficient way of producing energy as much less fuel is needed for the same amount of energy
what are 3 cons of nuclear power
-produces nuclear waste which is difficult to store
-an accident could spread radioactive material over a large area
-many people think that it is dangerous so do not want nuclear power stations to be built
what are 2 pros of nuclear power
- stations do not produce carbon dioxide
- supplies will last longer than fossil fuels
what is nuclear fission
is when a large unstable nucleus is split into 2 smaller ones which releases energy
how is nuclear fission used in power stations
a uranium-235 atom is split into 2 smaller nuclei to release energy by shooting it with a neutron. when the nucleus is split 2 daughter cells and extra neutrons will be released which will go on and collide with more nuclei creating a controlled chain reaction, any extra neutrons will be absorbed
how is electricity generated from nuclear power stations in steps
- fuel rods containing uranium undergo nuclear fission releasing thermal energy
- the thermal energy from the nuclear fusion is taken by a coolant to heat water and produce steam
- the steam causes turbines to rotate which turns the generator to generate electricity
- the steam is cooled back into water in a condenser so it can be used again
what are the features of a nuclear reactor core
fuel rod
control rods
moderator
shielding
what are the control rods and what are their purpose
are rods that absorb neutrons to prevent the reaction from speeding up, they can be pushed further in or pulled out to decrease or increase the speed of the reaction
what is a moderator and what is its purpose
is material (often graphite or water) that is used to slow down the neutrons so that the fission can occur
what is shielding made out of and what is its purpose
concrete prevents radiation and stray neutrons from escaping
what happens to the products of nuclear fissions
the radioactive daughter products need to be disposed of safely, they will be stored until the activity decreases to a safe level
what is nuclear fusion
involves the joining of smaller nuclei to form larger nuclei which releases energy
where does nuclear fusion happen naturally
in stars
why is nuclear fusion difficult
the nuclei need to get very close to each other to react however the positive charges on the nuclei repel each other (electrostatic repulsion) so very high temperatures and pressures are needed to overcome those forces
