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GCSE Physics: Topic 7 > Nuclear fission > Flashcards

Flashcards in Nuclear fission Deck (10):

What is nuclear fission?

Splitting of an atomic nucleus into two smaller nuclei


What does fission process results in the emission of?

  • Two or three high-speed neutrons
  • energy - in forms of gamma radiation and kinetic energy of the nuclei and neutrons


Naturally occuring uranium is mostly?

Uranium-238 which which is non-fissionable


What do most nuclear reactors use?

'Enriched' uranium that contains 2-3%

 uranium -235 which is fissionable

some reactors use plutonium-239


What is induced fission?

Occurs when a neutron absorbed by uranium-235 nucleus or plutonium-239 nucleus and nucleus splits 


What is spontaneous fission?

Occurs without a neutron being absorbed


When does a chain reaction occur?

When neutrons released from each fission event

causes further fission events to occur 


What is the result of nuclear reactor being controlled?

One fission neutron per fission, on average, goes on to produce further fission


What is function of control rods in nuclear reactor core?

Absorbs surplus neutrons

the depth of rods in the core is adjusted to maintain a steady chain reactions


How is moderator used in nuclear reactor?

Fast neutrons don't cause further fission so in reactor core

moderator used to slow high-speed neutrons