Topic 4- Nuclear Fission and Fusion Flashcards
What is nuclear fission?
The splitting of large, unstable nuclei to form smaller more stable nuclei
Give an example of a fissionable isotope
Uranium- 235
What usually needs to happen to induce fission
The unstable nuclei must absorb a neutron
Spontaneous fission is rare
what is emitted in a fission reaction?
Two smaller nuclei
Two or three neutrons
Gamma rays
Energy
What forms of energy do all fission products have?
Kinetic energy
What takes place during a chain reaction in a nuclear reactor
An unstable nucleus absorbs a neutron
The nucleus undergoes fission and release 2 or 3 further neutrons
These induce more fission which results in a chain reaction
What is the concenquence of an uncontrolled chain reaction?
The rate of fission events becomes to high and result in the production of too much energy
This can lead to a nuclear explosion
What are the three main components of the core a nuclear reactor?
Fuel rods
Control rods
moderator
What is the role of the moderator in a nuclear reactor?
To slow down the neutrons so they are travelling at speeds which allow them to be absorbed by fissile nuclei and cause fission
How is the chain reaction in a fission reactor kept under control?
Control rods are positioned in between the fuel rods
The rate of fission is controlled by moving these rods up and down
The lower the rods are inserted the slower the rate of fission
What term is used to describe nuclei in which fission can be induced through the absorption of slow neutrons
Fissile Nuclei
What is nuclear fission
The joining of two light nuclei to produce a heavier nuclei and release energy
Name two isotopes of hydrogen which are commonly used in nuclear fusion
Deuterium and Tritium
Which releases more energy, nuclear fission or nuclear fusion
nuclear fusion
Explain the difficulty of generating energy through nuclear fusion
Fusion requires very high temperatures which in itself requires large quantities of energy and also requires casing which can withstand them