With the unprecedented urbanization in developing countries, the demand for energy is bound to rise and large-scale generation of electricity will be necessary to satisfy the electricity needs. New sources of energy are thus needed due to calls for reduced CO2 emission sources and importance of investing in reliable energy options. It is envisaged that by mid-21st century, fusion will be available as an energy option. This should be employed in the provision of sustainable and environmental friendly energy to meet both the European and global energy requirements.
Inside the sun, fusion reactions take place at extremely high temperatures and massive gravitational pressures.
The sun and stars are powered by fusion hence an important energy that is necessary for the well-being of living things on earth. It is referred to as fusion due to the merging of light atoms, for example, hydrogen under exceedingly high temperatures and pressure. The centre of the sun has extreme conditions, for instance; the temperature is 15 million ºC, and any gas material is converted to plasma, which is regarded as the fourth form of matter; the other three states are solid, liquid and gas.
Plasma is referred to as an ‘electrically-charged gas’ where the negatively charged electrons in atoms are completely isolated from the atomic nuclei that are positively charged. However, plasma is rarely found on earth but 99% of the universe is estimated to exist as plasma.
For the process to be simulated on earth, gases need to be exposed to temperatures of approximately 150 million degrees ºC to completely ionize the atoms. The most easily achievable fusion reaction is the reaction between nuclei of two hydrogen isotopes i.e deuterium and tritium resulting in a helium nucleus that has high energy. Deuterium can be obtained from water while tritium is extracted from the fusion reaction with lithium.
How Fusion takes place
Fusion of two atoms, deuterium and tritium to form a helium nucleus that contains lots of energy.
Scientists have developed devices that can produce temperatures that are 10 times the strength of the sun. To produce such extremely high temperatures, powerful heating must be present and loss of temperature should be kept to a minimum. Thermal loss is enabled by keeping the heated fuel particles away from the vessel lining. To achieve this, a magnetic “cage’’ is created using powerful magnetic fields that prevent the escape of these particles. Confinement of plasma for relatively longer periods is necessary to allow fusion to take place thus produce energy.
A doughnut-shaped container holds the plasma in a tokamak. Special coils create a magnetic field, and the plasma particles are forced to move spirally without coming into contact with the lining of the vessel.
The tokamak is a Russian word referring to a magnetic chamber with a torus shape. Scientists have been successful in the production of gases with temperatures more than 10 times that of the fusion devices. Nevertheless, megawatts of power have been produced within very short periods. The European region has achieved this through the Joint European Torus (JET), largest fusion device globally and currently holds the world record for fusion power.
Currently, approximately 2000 scientists and engineers are working on a number of fusion R&D projects in more than 20 laboratories, including JET.
The European and energy needs of other parts of the world can be satisfied by fusion energy. Nevertheless, an international collaboration on an experimental facility called ITER (meaning ‘the way’ in Latin) is underway. ITER is the world’s largest energy project that seeks to provide a solution to the increasing demand for energy through fusion technology.
Source: Fusion For Energy (Europa)