Two British companies have just announced that they are confident they have harnessed the power of fusion to create a self-replenishing power source in a controlled manner, fusion energy is the same process as the sun* uses to function and continue burning with a highly energetic source. On earth, we humans have been trying since the 1950s to create this energy and deliver a clean reaction in a controlled state converting nuclei in plasma reactions with some of the mass being turned into a useable and ongoing energy source.
*fusion accounts for around 85% of the suns energy output, it is estimated
Since the 1950s when the technology was first demonstrated by the UK Atomic energy Authority (UKAEA) with their ZETA fusion reactor, countless industrial bodies and smaller setups have tried in vain to harness this useful energy but been thwarted along the way, the Original ZETA programme shut down in 1968 but certainly paved the way to today’s ongoing progression and scientific with engineering breakthroughs.
There are two main standards that have progressed with the development of fusion reactors but the main object of the process is to combine two lighter atomic nuclei to form a heavier nucleus:
The method that originated in the Soviet Union in the 1950s utilises a vessel that holds the fuel which is normally deuterium and its hydrogen isotopes as well as radioactive tritium to start the reaction (tritium is mined and enriched for use in the reactor vessel and deuterium can be distilled from all forms of water including that of the sea).
The deuterium and tritium are superheated with massive amounts of electricity, the fuel is kept in place with massive powerful magnets whilst the temperature is raised above 100 million Celcius – the atomic nuclei fuse and then vast amounts of energy are released that can be harnessed.
Up til now more energy has been required to start the reaction than it outputs once going, it is hoped eventually to have a system that will run in a controlled manner once the reaction is started using less energy than in the start-up state, fusion reactions are different to nuclear reactions in that they are not self-sustaining but need to be kept going with external factors.
The new generation of experimental reactors known as step reactors (Spherical Tokamak for Energy Production) that followed on from the ZETA reactors are being developed by the UKAEA and they expect to have a working fusion reactor by 2040.
The First light fusion company, on the other hand, is pioneering a quite different approach, instead of superheating the reagents within a strong magnetic field they aim to initiate the fusion process by firing a large number of small copper projectiles at hypersonic speed continually into a small capsule containing the deuterium and tritium fuel, this is a pulsed energy transfer with the energy from each shot ending up in liquid lithium coolant for later reuse.
First light hopes to demonstrate early in 2020 that the system can achieve fusion and even output some ‘gain’, this is where the output power is more than the inputted power used to initiate the reaction, they hope to have a full commercial fusion system running by 2024.
As with nuclear fusion, fusion reactors can have their own set of problems including damage from the constant neutron rays bombarding and escaping the vessels, there is also the very real problem of nuclear waste and possible containment leakage as tritium is a form of ionizing radiation that can be the cause of some cancers, it has a half-life of 12.5 years due to its unstable nature, as with all radioactive isotopes it decays and as it does it emits beta radiation.
With a fusion-fission hybrid system, it is possible to create energy and nuclear byproducts to produce energy and as well as dangerous fissile material, the possible performance of such a system would probably not justify its cost over a normal fissile system, a more likely scenario is that a fusion system would be modified to become a breeder of fissile material that could be used in nuclear bombs and weapons systems.
As with most world-changing technologies there are good and bad sides and in the right hands, a newer and cleaner form of energy production is almost with us that could possibly provide an inexhaustible supply of energy without pollution or adding to the global warming problem, if in careless hands we are at risk from containment leaks and other damaging incidents, if in bad hands, controlled and dirty nuclear bombs or mass pollutants could be created and so a nuclear proliferation risk from fusion reactors are quite real.