2349878
Description
Flashcards by Aimee Shanks, updated more than 1 year ago
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Created by Aimee Shanks
over 9 years ago
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| Question | Answer |
| Definition of nuclear fission | Splitting up of big atomic nuclei |
| How is it nuclear fission used? | Used to generate electricity using nuclear reactors. A controlled chain reaction takes place in which atomic nuclei split up and release heat. This heats water for steam which then turns a turbine |
| What fuel is usually used in nuclear fission? | uranium-235 or plutonium-239 |
| Info on nuclear reactor fission: | -reactor is surrounded by a large concrete container to absorb some heat and to control it -control rods keep chain reaction under control -coolant cools down system using water -moderator slows down neutrons to create more fission events |
| What are the safety issues regarding nuclear fission? | -chain reaction can become uncontrollable -it produces radioactive waste which is difficult and expensive to dispose |
| Explain how chain reactions happen in nuclear fission | -when nuclear fission happens a slow moving electron is absorbed into the uranium or plutonium nucleus. This makes the nucleus unstable -this causes it to split and spit out 2 or 3 neutrons -this could then lead to being absorbed into another nucleus and therefore keeping the reaction going |
| Definition of nuclear fusion | The joining of small atomic nuclei. This is when the two light nuclei e.g hydrogen join to create a larger nucleus |
| Conditions needed for nuclear fusion? | -very high temperature -high pressure -if these are not high enough they repel each other |
| How much energy does nuclear fusion create? | Lots of energy. More then fission . People are trying to develop reactors for it to create electricity |
| Why can't nuclear fusion be used yet for generating electricity? | - requires extremely high temperatures (around 10,000,000 decree c) to fuse - the high pressure and temps means that it cannot be held in normal containers |
| Where does nuclear fusion happen in nature? | The stars |
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