Nuclear fission and fusion (4.4) (R) Flashcards
What is nuclear fission?
the splitting of a large and unstable nucleus
2 elements needed
What are common examples of unstable nuclei?
uranium and plutonium
Spontaneous fission is (…)
rare
Usually, what must first happen for nuclear fission to occur?
the unstable nucleus must first absorb a neutron
Describe what happens in nuclear fission
The nucleus undergoing fission splits into two smaller nuclei, roughly equal in size, and emits two or three neutrons plus gamma rays. This process may repeat in a chain reaction.
Energy is released by the fission reaction.
All of the fission products have (…) energy
kinetic
The neutrons related during nuclear fission may go on to start a (…) reaction
chain
What is a chain reaction controlled in?
a nuclear reactor
The chain reaction is controlled in a nuclear reactor to control the (…) released
energy
What is an explosion caused by a nuclear weapon is caused by?
An uncontrolled chain reaction
How is a chain reaction controlled in a nuclear reactor?
In a nuclear reactor there are control rods (made of Boron) that absorb extra neutrons to control energy released
What happens in a chain reaction?
Neutron hits nucleus. Nucleus splits into (2) smaller nuclei and emits 2 or 3 (3 at start of chain reaction) neutrons, these neutrons will then hit some more nuclei and the process repeats.
What is nuclear fusion?
The joining of two light nuclei to form a heavier nucleus
What happens to some of the mass in nuclear fusion?
Some of the mass may be converted into the energy of radiation
How does nuclear fusion apply to stars?
It is how stars release energy when hydrogen atoms fuse to make helium
requires very high temperatures and pressures, hard to replicate and would be costly
Draw a chain diagram?
Big circle represents the nucleus, the smaller circle represents the neutrons emitted
Please note that for the fission reaction, only 3 neutrons can be released, after that 2 or 3 can. The graph is wrong
