Nuclear fission converts its nuclear energy into huge quantities of heat energy. A nuclear reactor uses this heat to make steam. The steam then turns turbines to generate electricity.
Problems with Nuclear Fission zz
z z
Uranium needs to be mined from the ground as an ore. This activity is expensive and dangerous.
The waste from uranium is radioactive. Radiation can cause mutations in DNA.
Learn more about mutation and radiation in Biological World 4.3
zz
Radioactive material decays very slowly. This means it can continue to cause harm for thousands of years.
zz
The splitting of a uranium isotope causes the release of more neutrons, which can cause further fission. This type of reaction is known as a chain reaction. If a nuclear chain reaction gets out of control, it can cause a large explosion. An uncontrolled chain reaction is the source of energy for an atomic bomb.
People and Science
In 1938, German scientists Fritz Strassman and Otto Hahn discovered nuclear fission by firing neutrons at uranium nuclei. They were the first people to realise that the atom could be split into smaller parts.
Lise Meitner, an Austrian physicist, was also part of this team. Her part in the discovery was overlooked because she was Jewish. Although she had no hand in the making of it, she became known as ‘the mother of the atomic bomb’.
Fig. 24.2.4
Lise Meitner and Otto Hahn in the laboratory
z Fig. 24.2.2
Uranium, the fuel for nuclear fission
24.2
z
Fig. 24.2.3
Radioactive hazard symbol
Isotope versus element
The isotope of uranium used for nuclear fission has a mass number of 235 and an atomic number of 92. Calculate how many neutrons are contained in a nucleus of this isotope. Compare this number with the number of neutrons in a nucleus of the most common isotope of uranium on the periodic table.
