Flashcards
Controlled Nuclear reactors
Flashcards do conjunto (19)
- 1What do Nuclear reactors use rods of?Uranium that are rich in U-235 for fuel and U-238
- 2What type of reaction do fission reactors produce?A chain reaction
The fission produces more neutrons which then induce other nuclei to fission - 3When will neutrons cause a chain reaction?When they are slowed down
Allows them to be captured by the uranium nuclei - 4What are these slowed down neutrons called?Thermal neutrons
- 5What must the U-235 rods be placed in?A moderator such as water to slow down/absorb neutrons
- 6What type of moderator must you use?One which will slow down some neutrons enough so they can cause further fission and keep the reaction going at a steady rate
- 7What happens if you choose a moderator which absorbs more neutrons at a higher temperature?It will decrease the chance of meltdown if the reactor overheats
as it will naturally slow down the reaction - 8What is the critical mass?The amount of fuel to keep the reaction going at a steady rate where one fission follows another
- 9What happens if you have any less then the critical mass (sub-critical mass) ?The reaction will just peter out
- 10What mass of fuel do Nuclear reactors use?A super-critical mass
Where several new fission's normally follow each fission - 11What do Nuclear reactors do to control the rate of fission?Use control rods
- 12How do control rods control the chain reaction?By limiting the number of neutrons in the reactor.
These absorb neutrons so that the rate of fission is controlled - 13What are control rods made up of?A material which absorbs neutrons eg. boron
- 14In an emergency what will the reactor do?Shut down automatically by the release of the control rods into the reactor which will stop the reaction as soon as posssible
- 15What does coolant do?sent around the reactor to remove the heat produced by the fission
- 16What material is the coolant?Often the same water that is being used in the reactor as the moderator
- 17What can the heat from the reactor be used for?To make stream for powering electricity-generating turbines
- 18What is the nuclear reactor surrounded by?A thick concrete case which acts as shielding
- 19What does the shielding do?Prevents radiation escaping and reaching the people who work in the power stations
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- Physics unit 5 FlashCards sobre Controlled Nuclear reactors, criado por sammy414 em 19-02-2014.
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- sammy414
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